TWI854006B - Adhesive tape - Google Patents

Abstract

The present invention provides an adhesive tape which can suppress the increase of the adhesive force to the adherend even when placed under high temperature conditions, and can sufficiently reduce the adhesive force to the adherend by irradiating active energy rays, so that the adherend can be easily debonded without contaminating the adherend. The adhesive tape of the present invention is an adhesive tape having a thin sheet substrate through which active energy rays can pass and an adhesive layer disposed on the surface of the thin sheet substrate, the adhesive layer containing an acrylic adhesive polymer having a carbon-carbon double bond and a functional group, a photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent that reacts with the functional group, and a filler, and the filler has a strength of 20 MPa or more at 30% deformation in a micro compression test.

Description

Adhesive tape

The present invention relates to an adhesive tape, and more particularly to an adhesive tape for temporarily fixing electronic components, which is used to bond electronic components during processing and to debond them after high-temperature processing.

In recent years, adhesive tapes have been frequently used in the manufacturing process of industrial products. The adhesive tapes used in these processes are mostly required to adhere well during use and be easily removed after use. Based on these expectations, there is a known technology that allows the adhesive of the tape to be easily removed by applying heat or active energy rays to the adhesive after use to produce a chemical reaction. Generally, active energy rays refer to non-thermal energy such as light and radiation. And generally, the reaction mechanism caused by active energy rays is different from the reaction mechanism caused by heat.

Patent document 1 describes a radiation-curable adhesive tape used for wafer fixation when semiconductor wafers are cut. The adhesive layer of the radiation-curable adhesive tape contains spherical particles of acrylic resin polymer. Therefore, since the bonding force is sufficiently reduced by radiation irradiation, even large components will not be stretched after radiation irradiation and can be easily picked up.

Patent document 2 describes an adhesive composition that has both high-level adhesion and reworkability for use in surface protection films for displays, optical parts, or substrates. The adhesive composition of the surface protection film contains a hydroxyl-containing urethane prepolymer, a multifunctional (meth)acrylate, a thermal radical initiator, a crosslinking agent, and a photoradical initiator. Therefore, the adhesion will not be too large, and by light irradiation, the adhesion during peeling is reduced compared to the adhesion state, so that it can have both high-level adhesion and reworkability, and can also reduce the occurrence of adhesive layer peeling. [Prior technical document] [Patent document]

[Patent Document 1] Japanese Patent Publication No. 9-8109 [Patent Document 2] Japanese Patent Publication No. 2019-104870

[Invent a method to solve the problem]

The objects to be bonded by the adhesive tape in the above steps are mostly glass or silicon wafers. In recent years, micro LED displays have attracted much attention as the next generation of display devices. However, in the manufacture of these micro LED displays, in order to accurately arrange the LED chips on the display substrate surface and to transport them with good precision, the transfer technology using bonding tape or adhesive tape is under consideration. These electronic components are sometimes processed under high temperature conditions of about 160°C or above. Examples include processes such as solder reflow processing steps (e.g., reflow temperature 260°C) or curing steps of the sealing resin for primary sealing (e.g., curing temperature 165°C).

The radiation-curable adhesive tape of Patent Document 1 may increase the bonding strength of the adhesive layer to the adherend when temporarily placed under high temperature (e.g., above 160°C), and may not sufficiently decrease the bonding strength even when irradiated with radiation.

The adhesive composition of Patent Document 2 is a urethane adhesive, and its initial adhesive force is relatively low. When the adhesive composition is used for temporary fixing of electronic parts, it may deviate from a specific position during processing or transportation, or even peel off, depending on the size or weight of the electronic parts to be bonded. In addition, since the adhesive composition of Patent Document 2 contains a low molecular weight multifunctional (meth)acrylate, there is a risk of contaminating electronic parts, or when temporarily placed at high temperatures (e.g., above 160°C), the adhesive layer may have a greater adhesive force on the bonded object, and even if irradiated with radiation, the adhesive force may not be sufficiently reduced.

The present invention is to solve the above-mentioned problem. Its purpose is to provide an adhesive tape that can suppress the increase of the bonding force to the adherend even when placed under high temperature conditions, and can sufficiently reduce the bonding force to the adherend by irradiating active energy rays, so that the adherend can be easily debonded without contaminating the adherend. [Means for solving the problem]

The present invention provides an adhesive tape having a sheet-like substrate through which active energy rays can pass and an adhesive layer disposed on the surface of the sheet-like substrate. The adhesive layer contains an acrylic adhesive polymer having a carbon-carbon double bond and a functional group, a photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent that reacts with the functional group, and a filler. The filler has a strength of 20 MPa or more at 30% deformation in a micro-compression test.

In the above aspect, the thermal polymerization initiator is preferably contained in an amount ranging from 0.1 to 31.0 parts by mass relative to 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group.

Furthermore, when the average particle size of the filler is set to R (μm) and the thickness of the adhesive layer is set to D (μm), the ratio of R to D (R/D) is preferably in the range of 0.20 to 1.00.

Furthermore, it is preferred that the average particle size of the filler is in the range of 2-30 μm.

Furthermore, the filler is preferably contained in an amount ranging from 1.0 to 62.0 parts by mass relative to 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group.

Furthermore, it is preferred that the carbon-carbon double bond content of the acrylic adhesive polymer having carbon-carbon double bonds and functional groups is in the range of 0.40-1.85 mmol/g.

Furthermore, it is preferred that the adhesive layer comprises an oligomer having a carbon-carbon double bond.

Furthermore, it is preferred that the oligomer having carbon-carbon double bonds has two or more carbon-carbon double bonds, a carbon-carbon double bond equivalent is in the range of 250 to 1,400, and a weight average molecular weight is in the range of 1,500 to 4,900.

Furthermore, it is preferred that the oligomer having a carbon-carbon double bond is contained in an amount of at most 120 parts by mass relative to 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group.

Furthermore, the above-mentioned adhesive tape is preferably suitable for use as an adhesive tape for temporarily fixing electronic components. [Effect of the invention]

According to the present invention, an adhesive tape is provided that can suppress the increase of the adhesive force to the object to be adhered even when placed under high temperature conditions, and can sufficiently reduce the adhesive force to the object to be adhered by irradiating active energy rays. As a result, electronic parts such as components processed under high temperature conditions using the adhesive tape of the present invention can be easily detached from the adhesive tape after irradiating active energy rays. That is, after being temporarily fixed with the adhesive tape, the electronic parts processed under high temperature conditions can eventually be detached from the adhesive tape without contamination or damage.

The adhesive tape of the present invention comprises a sheet-like substrate and an adhesive layer disposed on the surface of the sheet-like substrate. The adhesive layer can be disposed on one side or on both sides of the sheet-like substrate.

[Flake-like substrate] The sheet-like substrate is not particularly limited as long as it is a material that can transmit active energy rays and has strength to withstand the use environment. Specific examples include homopolymers or copolymers of α-olefins such as polyethylene, polypropylene, ethylene-propylene copolymer, polybutene-1, poly-4-methylpentene-1, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-acrylic acid copolymer, ionomer, etc., chlorinated vinyl homopolymers or copolymers such as polyvinyl chloride, chlorinated ethylene-vinyl acetate copolymer, chlorinated ethylene-ethylene-vinyl acetate copolymer, fluorinated ethylene-ethylene copolymer, vinylidene fluoride-ethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer, etc., engineering plastics such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polymethyl methacrylate, etc., alone or in mixture. Among them, polyethylene terephthalate is preferred from the viewpoint of wide availability and heat resistance. The thickness of the sheet-like substrate is generally 5 to 200 μm, preferably 10 to 100 μm.

[Adhesive layer] An active energy ray-curing adhesive is used in the adhesive layer. Active energy ray-curing adhesives have an appropriate adhesive force that can fully fix the adherends, but since the storage elastic modulus of the adhesive increases significantly due to a three-dimensional crosslinking reaction caused by exposure to active energy rays, and the glass transition temperature also increases, the volume of the adhesive also shrinks, so the adhesive force to the adherend is greatly reduced. This makes it easier to debond the adherend, and at this time, it is difficult for the adhesive to remain on the adherend. Active energy ray-curing adhesives contain functional groups such as carbon-carbon double bonds that show reactivity by irradiation with active energy rays.

The active energy ray-curable adhesive used in the present invention contains an acrylic adhesive polymer, a photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent, and a filler. Generally, an active energy ray-reactive group (carbon-carbon double bond) is contained in the acrylic adhesive polymer.

The adhesive layer is formed on the thin sheet substrate, for example, by a coating method. That is, the active energy ray-curing adhesive is diluted with an organic solvent such as toluene, ethyl acetate, etc. to obtain an adhesive layer coating liquid. Next, the obtained adhesive layer coating liquid is coated on the surface of the thin sheet substrate and dried and hardened to form the adhesive layer. It is preferred to bond the adhesive layer to a thin sheet substrate that has been subjected to a demolding treatment. Alternatively, the adhesive layer coating liquid may be temporarily coated on the surface of the thin sheet substrate that has been subjected to a demolding treatment and dried, and then transferred to the thin sheet substrate and hardened to form the adhesive layer. The thickness of the adhesive layer is not particularly limited, but is generally 5 to 100 μm, preferably 10 to 30 μm, and more preferably 20 to 30 μm.

In order to improve the adhesion between the adhesive layer and the sheet-like substrate, the surface of the sheet-like substrate may be subjected to corona treatment, plasma treatment, or application of a primer composition, and then the adhesive layer coating liquid may be applied to the surface of the sheet-like substrate.

(Acrylic adhesive polymer) Acrylic adhesive polymers are used to bond the adhesive layer of adhesive tape to electronic parts during processing of electronic parts of the adherend. Acrylic adhesive polymers are used for those with carbon-carbon double bonds in the molecule. When the adherend is debonded, the carbon-carbon double bonds are irradiated with active energy rays to cause free radical addition reactions, which highly crosslink the polymer chains, increase the storage elastic modulus of the adhesive layer, and also increase the glass transition temperature, so that the deformation rate of the adhesive layer during peeling (debonding) is reduced. Since the volume is also shrunk, the effect of reducing the adhesion of the adhesive layer is improved.

The method for producing the acrylic adhesive polymer having a carbon-carbon double bond and a functional group is not particularly limited, but a common example is a method in which a (meth)acrylate is copolymerized with an unsaturated compound containing a functional group to obtain a copolymer, and a compound having a functional group capable of undergoing an addition reaction with the functional group of the copolymer and a carbon-carbon double bond is subjected to an addition reaction.

The functional group referred to here refers to a thermally reactive functional group that can coexist with a carbon-carbon double bond. Examples of such functional groups are functional groups that thermally react with active hydrogen groups such as hydroxyl, carboxyl, and amine groups, and active hydrogen groups such as glycidyl groups. The so-called active hydrogen group refers to a functional group having an element other than carbon, such as nitrogen, oxygen, or sulfur, and a hydrogen directly bonded thereto.

As the above-mentioned addition reaction, there are methods such as reacting the hydroxyl groups located at the side chains of the above-mentioned copolymer with an isocyanate compound having a (meth)acryloyloxy group (e.g., 2-methacryloyloxyethyl isocyanate), reacting the carboxyl groups located at the side chains of the above-mentioned copolymer with glycidyl (meth)acrylate, or reacting the glycidyl groups located at the side chains of the above-mentioned copolymer with (meth)acrylic acid. In addition, during the above-mentioned reactions, the above-mentioned acrylic adhesive polymer is crosslinked by a crosslinking agent described later, and in order to increase the molecular weight, functional groups such as hydroxyl groups, carboxyl groups, or glycidyl groups are left in advance. In this way, an acrylic adhesive polymer having an active energy ray reactive group (carbon-carbon double bond) such as a (meth)acryloyloxy group and a functional group can be obtained.

In the above addition reaction, a polymerization inhibitor is preferably used to maintain the active energy line reactivity of the carbon-carbon double bond. As such polymerization inhibitor, a quinone polymerization inhibitor such as hydroquinone monomethyl ether is preferred. The amount of the polymerization inhibitor is not particularly limited, but is generally 0.01 to 0.1 parts by mass relative to the total amount of the base polymer and the radiation-reactive compound.

The acrylic adhesive polymer preferably has a weight average molecular weight of 100,000 to 2,000,000, and more preferably 300,000 to 1,500,000. When the weight average molecular weight of the acrylic adhesive polymer is less than 100,000, it is difficult to obtain a solution of the adhesive composition with a high viscosity of several thousand to tens of thousands of cP in consideration of the coating property, so it is not good. In addition, there is a possibility of reduced adhesion, insufficient retention of the adherend during processing, or contamination of the adherend during debonding. On the other hand, when the weight average molecular weight exceeds 2,000,000, it does not particularly cause a problem in the properties of the adhesive tape, but it is difficult to mass produce the acrylic adhesive polymer. For example, the acrylic adhesive polymer may gel during synthesis, which is not good. Here, the weight average molecular weight refers to a standard polystyrene conversion value measured by gel permeation chromatography.

The acrylic adhesive polymer preferably has a carbon-carbon double bond content of 0.10~2.00 mmol/g, more preferably 0.40~1.85mmol/g. When the carbon-carbon double bond content of the acrylic adhesive polymer is less than 0.10mmol/g, even if it is irradiated with active energy rays, the photo-radical crosslinking reaction is not sufficiently induced, and as a result, the bonding force cannot be sufficiently reduced, and the bonded object is difficult to debond. On the other hand, when the carbon-carbon double bond content exceeds 2.00mmol/g, it does not particularly become a problem in terms of the properties of the adhesive tape, but it is not practical from the perspective of the storage stability of the adhesive tape against light. In addition, the carbon-carbon double bond content of the acrylic adhesive polymer can be calculated by measuring the iodine value of the acrylic adhesive polymer.

The main skeleton of the acrylic adhesive polymer is composed of a copolymer containing an alkyl (meth)acrylate monomer and a monomer containing an active hydrogen group and/or a monomer containing a glycidyl group. Examples of the alkyl (meth)acrylate monomer include hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecanyl (meth)acrylate, octadecyl (meth)acrylate, and the like, which have 6 to 18 carbon atoms; or pentyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, ethyl (meth)acrylate, methyl (meth)acrylate, and the like, which have 5 or less carbon atoms. Examples of the monomer containing an active hydrogen group include hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, carboxyl group-containing monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc., acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride, (meth)acrylamide, N,N-dimethylformamide, etc. Amide monomers such as 1,2-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxymethylpropane (meth)acrylamide, N-methoxymethyl (meth)acrylamide, and N-butoxymethyl (meth)acrylamide, and amino group-containing monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and tert-butylaminoethyl (meth)acrylate, etc., are used. Examples of glycidyl group-containing monomers include glycidyl (meth)acrylate. The content of the heat-reactive functional groups that can coexist with the carbon-carbon double bond is not particularly limited, but is preferably in the range of 5 to 50 mass % relative to the total amount of the copolymerized monomer components.

Specific examples of the copolymers obtained by copolymerization include copolymers of 2-ethylhexyl acrylate and acrylic acid, copolymers of 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate, and terpolymers of 2-ethylhexyl acrylate, methacrylic acid, and 2-hydroxyethyl acrylate, but the present invention is not particularly limited thereto.

The acrylic adhesive polymer may contain other copolymer monomers as needed for the purpose of improving cohesion and heat resistance. Specific examples of such other copolymer monomers include cyano monomers such as (meth)acrylonitrile, olefin monomers such as ethylene, propylene, isoprene, butadiene, isobutylene, styrene monomers such as styrene, α-methylstyrene, vinyl toluene, vinyl ester monomers such as vinyl acetate, vinyl propionate, vinyl ether monomers such as methyl vinyl ether, ethyl vinyl ether, halogen-containing monomers such as vinyl chloride, vinylidene chloride, methoxyethyl (meth)acrylate, and the like. The present invention also includes monomers containing alkoxy groups such as ethoxyethyl (meth)acrylate, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, and N-(meth)acryloylmorpholine. These other copolymerizable monomer components may be used alone or in combination of two or more.

(Crosslinking oligomer) The above-mentioned adhesive layer preferably contains an oligomer having a carbon-carbon double bond. When the adhesive layer is irradiated with active energy rays, the oligomers cause addition reactions between the oligomers or between the oligomers and the above-mentioned acrylic adhesive polymer in the adhesive layer and are highly crosslinked. As a result, compared with the case where the adhesive layer does not contain a crosslinking oligomer, the storage elastic modulus and glass transition temperature of the adhesive layer are further increased and the volume is also more shrunk, so that when the adherend is debonded, the effect of reducing the adhesion of the adhesive layer is improved. Examples of crosslinking oligomers include photopolymerizable multifunctional oligomers.

The crosslinking oligomer preferably has two or more carbon-carbon double bonds. Furthermore, the crosslinking oligomer preferably has a weight average molecular weight of 1,000 to 5,000, more preferably 1,500 to 4,900. If the weight average molecular weight of the crosslinking oligomer is less than 1,000, there is a risk of contaminating the bonded material when the amount of the crosslinking oligomer is too large. Furthermore, when the amount of carbon-carbon double bonds in the crosslinking oligomer is too small, the bonding strength to the bonded material increases excessively when placed under high temperature conditions, and there is a risk that the bonding strength may not be sufficiently reduced even when irradiated with active energy rays during debonding. On the other hand, if the weight average molecular weight of the crosslinking oligomer exceeds 5,000, the amount of carbon-carbon double bonds in the crosslinking oligomer is small, the degree of hardening and shrinkage of the adhesive layer is small, and there is a risk that the effect of further reducing the adhesion may not be obtained. The weight average molecular weight here refers to the standard polystyrene conversion value measured by a gel permeation chromatograph.

The double bond equivalent of the crosslinking oligomer is preferably in the range of 150 to 1,500, more preferably in the range of 250 to 1,400, and even more preferably in the range of 250 to 490. When the double bond equivalent of the crosslinking oligomer is less than 150, the crosslinking density of the adhesive layer becomes higher when irradiated with active energy rays, and the flexural elastic modulus becomes too high. Therefore, when the adherend is lifted up by the adhesive tape and peeled off from the adhesive tape, if the mechanical strength of the adherend is relatively low (specifically, a semiconductor chip or thin film glass, etc.), there is a risk that the adherend may break. In addition, when the content of the cross-linking oligomer is high, there is a possibility that the storage stability against light may deteriorate. On the other hand, if the double bond equivalent of the cross-linking oligomer exceeds 1,500, the degree of hardening and shrinkage of the adhesive layer is small, and there is a possibility that the effect of further reducing the bonding force cannot be obtained. Here, the double bond equivalent is defined by the formula: double bond equivalent = molecular weight / number of double bonds in the same molecule. The value of the double bond equivalent defined by the above formula can be calculated from the amount of double bonds in the sample quantified based on the iodine value measured in accordance with JIS K0070:1992 and the mass or molecular weight of the sample. When the sample may contain multiple components, each component is separated as necessary, and the double bond equivalent is calculated by measuring the iodine value of each separated component.

Preferred crosslinking oligomers include polyacrylate oligomers, polyether oligomers, polyester oligomers, polyurethane oligomers, and other photopolymerizable multifunctional oligomers. Among them, polyurethane oligomers are preferred from the viewpoints of reducing adhesive leaching and improving adhesion to the adherend at high temperatures, and aliphatic polyurethane oligomers are more preferred from the viewpoint of easy control of reactivity. These photopolymerizable multifunctional oligomers may be used alone or in combination of two or more.

Examples of the polyacrylate oligomer include hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trihydroxymethylpropane tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy (meth)acrylate, and oligoester (meth)acrylate.

Examples of the polyether oligomer include polyethylene glycol, polypropylene glycol, polybutylene glycol, and end-capped products thereof having one or both ends capped with an end-capping agent such as methyl, phenyl, or (meth)acrylate.

Examples of polyester oligomers include ε-caprolactone and end-capped products thereof having one or both ends capped with an end-capping agent such as methyl, phenyl, or (meth)acrylate.

Examples of polyurethane oligomers include macropolyols such as polyether polyols, polyester polyols, polycarbonate polyols, and polybutadiene polyols, and urethane polyols such as reaction products of polyisocyanate monomers, and urethane acrylates such as reaction products of hydroxy (meth)acrylate monomers such as hydroxyethyl (meth)acrylate, phenyl glycidyl ether acrylate, pentaerythritol triacrylate, and glycerol dimethacrylate, and polyisocyanate monomers such as methylene diisocyanate, toluene diisocyanate, and isophorone diisocyanate, or the above-mentioned urethane polyols.

When the adhesive layer includes a crosslinking oligomer, the mixing ratio of the crosslinking oligomer is preferably 120 parts by weight or less, and more preferably 11 to 100 parts by weight, per 100 parts by weight of the acrylic adhesive polyol. When the mixing ratio of the crosslinking oligomer exceeds 120 parts by weight, it is not preferred because the adhesion to the adherend cannot be maintained during processing at high temperature. In addition, there is a risk of contaminating the surface of the adherend after debonding.

(Crosslinking agent) The adhesive layer of this embodiment further contains a crosslinking agent for increasing the molecular weight of the acrylic adhesive polymer. Such crosslinking agents are not particularly limited, and known crosslinking agents having functional groups that can react with the functional groups of the acrylic adhesive polymer, such as hydroxyl, carboxyl, and glycidyl groups, can be used. Specific examples include polyisocyanate crosslinking agents, epoxy crosslinking agents, aziridine crosslinking agents, melamine resin crosslinking agents, urea resin crosslinking agents, acid anhydride compound crosslinking agents, polyamine crosslinking agents, carboxyl-containing polymer crosslinking agents, etc. Among them, polyisocyanate crosslinking agents are preferably used from the viewpoint of reactivity and wide availability. These crosslinking agents can be used alone or in combination of two or more. The amount of the crosslinking agent is preferably in the range of 0.01 to 5.00 parts by mass, more preferably in the range of 0.10 to 3.00 parts by mass, relative to 100 parts by mass of the acrylic adhesive polymer. If the amount of the crosslinking agent is too much, depending on the type of the acrylic adhesive polymer, there is a risk that the adhesive force between the adhesive tape and the adherend will be reduced, or there is a risk that the uncrosslinked components will contaminate the adherend.

(Thermal polymerization initiator) Thermal polymerization initiator senses the heat during high temperature processing, especially after the adherend is attached to the adhesive tape, and is used to initiate a thermal free radical crosslinking reaction of a part of the carbon-carbon double bonds of the acrylic adhesive polymer or crosslinking oligomer, crosslinking the adhesive layer, and the storage elastic modulus and glass transition temperature also increase and harden compared to the state before the heat. As a result, the active energy ray-curing adhesive of the present invention containing a thermal polymerization initiator can greatly suppress the phenomenon that is typically seen in the previous active energy ray-curing adhesive that does not contain a thermal polymerization initiator, that is, when placed under high temperature conditions, the adhesive layer softens and is wetted by the adherend, causing the bonding force to the adherend to increase excessively. Furthermore, depending on the composition, the adhesive force to the adherend can also be substantially reduced before the active energy ray irradiation during debonding. In addition, in this state, the carbon-carbon double bonds of the active energy ray-curing adhesive are not necessarily completely consumed, but a portion of the carbon-carbon double bonds remain. Therefore, when the active energy ray is irradiated during debonding, the photo-radical crosslinking reaction of the remaining carbon-carbon double bonds proceeds through the photopolymerization initiator described later, so that the adhesive layer further hardens and shrinks, and finally the self-adhesive tape will not contaminate the adherend and damage it, and it can be easily peeled off. Furthermore, since the adhesive layer is mainly composed of an acrylic adhesive polymer, even if a free radical crosslinking reaction proceeds in a portion of the adhesive layer as described above, the adhesive force to the adherend can be maintained as much as possible during processing under high temperature conditions.

As the thermal polymerization initiator, a compound that generates free radical active species by heating is preferred, such as peroxide, azo compound or persulfate, etc. Among them, peroxide is preferred because it is easy to use appropriately according to the processing temperature of the object to be bonded.

Specific examples of peroxides include t-butyl hydroperoxide (10-hour half-life temperature: 167° C.), isopropylbenzene hydroperoxide (same: 158° C.), diisopropylbenzene hydroperoxide (same: 145° C.), p-menthane hydroperoxide (same: 128° C.), di-t-butyl peroxide (same: 124° C.), di(2-t-butylperoxyisopropyl)benzene (same: 119° C.), diisopropylbenzene peroxide (same: 117° C.), t-butyl peroxybenzoate (same: 104° C.), dibenzoyl peroxide (same: 74° C.), t-butyl peroxy-2-ethylhexanoate (same: 72° C.), t-hexyl peroxy-2-ethylhexanoate (same: 70° C.), etc. These may be used alone or in combination of two or more.

Examples of azo compounds include 1,1-azobis(cyclohexane-1-carbonitrile) (10-hour half-life temperature 88°C), 4,4'-azobis(4-cyanovaleric acid) (same 68°C), 2,2'-azobis(2-methylbutyronitrile) (same 67°C), 2,2'-azobis(2-methylpropionic acid) dimethyl ester (same 66°C), 2,2'-azobis(isobutyronitrile) (same 65°C), 2, Compounds such as 2'-azobisdimethylvaleronitrile (same as 52°C), 1,1'-azobis(1-acetyloxy-1-phenylethane) (same as 61°C), 2,2'-azobisisobutyric acid dimethyl ester (same as 67°C), azoisopropylbenzene, 2-(tert-butylazo)-2-cyanopropane, 2,2'-azobis(2,4,4-trimethylpentane), and 2,2'-azobis(2-methylpropane). These compounds may be used alone or in combination of two or more.

Examples of persulfate include sodium persulfate (10-hour half-life temperature: 71°C), ammonium persulfate (same: 62°C), sodium persulfate (same: 71°C), etc. These may be used alone or in combination of two or more.

The 10-hour half-life temperature of the thermal polymerization initiator used can be appropriately selected according to the processing temperature of the adherend. For example, when the processing temperature is 165-200°C, the 10-hour half-life temperature of the thermal polymerization initiator used is preferably in the range of 60-125°C. If the 10-hour half-life temperature is too low relative to the processing temperature, the adhesion to the adherend is too low when placed at the processing temperature, and there is a risk of affecting the processing operation (position shift or fall-off of the adherend). On the other hand, if the 10-hour half-life temperature is too high relative to the processing temperature, the effect of suppressing the increase of the adhesion to the adherend when placed at the processing temperature is reduced, and there is a risk that the adhesion will not be sufficiently reduced even if the active energy line is irradiated during debonding.

The amount of the thermal polymerization initiators used in the present invention is preferably in the range of 0.1 to 31.0 parts by mass, and more preferably in the range of 1.0 to 20.0 parts by mass, relative to 100 parts by mass of the acrylic adhesive polymer.

If the amount of the thermal polymerization initiator added is less than 0.1 parts by mass, the reactivity to heat is insufficient and the curing of the adhesive becomes insufficient. As a result, the increase in the adhesive force when placed under high temperature conditions cannot be fully suppressed, and there is a risk that it will be difficult to peel off the adherend even if the active energy beam is subsequently irradiated. On the other hand, if the amount of the thermal polymerization initiator added exceeds 31.0 parts by mass, the adhesive force to the adherend when placed under high temperature conditions is excessively reduced, and there is a risk of affecting the processing operation. In addition, there is a risk of contaminating the adherend.

(Photopolymerization initiator) The photopolymerization initiator is irradiated with active energy rays to the adhesive layer when the adhesive is released, and starts to cause the carbon-carbon double bonds of the acrylic adhesive polymer or crosslinking oligomer remaining in the adhesive layer after being placed under high temperature conditions to crosslink. As a result, the adhesive layer further hardens and shrinks under the irradiation of active energy rays, and the bonding force to the adhesive is reduced. As a photopolymerization initiator, a compound that generates free radical active species by ultraviolet rays is preferred. Specific examples include benzoyl ether-based initiators such as benzoyl methyl ether, benzoyl ethyl ether, benzoyl propyl ether, benzoyl isopropyl ether, benzoyl isobutyl ether, etc.; benzophenone-based initiators such as benzophenone, benzoyl benzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, and polyvinyl benzophenone; α-hydroxycyclohexyl phenyl ketone, 4-(2-hydroxyethoxy)benzene; Aromatic ketone-based initiators such as 2-hydroxy-2-propyl ketone, α-hydroxy-α,α'-dimethylacetophenone, methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, 2-methyl-1-[4-(methylthio)-phenyl]-2-pyrolinepropane-1, etc.; aromatic acetal-based initiators such as benzyl dimethyl acetal, etc. Initiators; thiothione-based initiators such as thiothione, 2-chlorothiothione, 2-methylthiothione, 2-ethylthiothione, 2-isopropylthiothione, 2-dodecylthiothione, 2,4-dichlorothiothione, 2,4-dimethylthiothione, 2,4-diethylthiothione, 2,4-diisopropylthiothione, etc.; biphenylacetyl-based initiators such as biphenylacetyl; benzoin-based initiators such as Benzoin-based initiators; α-keto compounds such as 2-methyl-2-hydroxypropiophenone; aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenylketone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; camphorquinone-based compounds; halogenated ketone-based compounds; acylphosphine oxide-based compounds; acylphosphonate-based compounds. These compounds may be used alone or in combination of two or more.

As the above-mentioned photopolymerization initiator, commercially available products can also be used. Specific examples include 1-hydroxy-cyclohexyl-phenyl ketone (trade name Omnirad 184, manufactured by IGM Resins B.V.), bis(2,4,6-trimethylbenzyl)-phenylphosphine oxide 1-hydroxy-cyclohexyl-ketone (trade name Omnirad 819, manufactured by IGM Resins B.V.), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name Omnirad 369, manufactured by IGM Resins B.V.), 2-benzyl-2-dimethylamino-4'-morpholinophenylbutyrophenone (trade name Omnirad 369E, manufactured by IGM Resins B.V.), and 1-hydroxy-cyclohexyl-phenyl ketone (trade name Omnirad 819, manufactured by IGM Resins B.V.). B.V.), 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholin-4-yl-phenyl)-butane-1-one (trade name Omnirad379EG, IGM Resins B.V.), etc. Among them, Omnirad 369, Omnirad 369E, and Omnirad 379EG are preferably used from the viewpoint of heat resistance that free radical active species can be sufficiently generated even when placed under high temperature conditions by irradiation with ultraviolet rays, etc.

The amount of the photopolymerization initiators added is preferably in the range of 0.1 to 10.0 parts by mass, more preferably 0.5 to 5.0 parts by mass, and even more preferably 1.0 to 2.0 parts by mass relative to 100 parts by mass of the acrylic adhesive polymer.

If the amount of the photopolymerization initiator added is less than 0.1 parts by weight, the photoreactivity to the active energy ray is insufficient, so the adhesive does not harden or shrink sufficiently, and there is a risk that it will be difficult to peel off the adherend even if the active energy ray is irradiated. On the other hand, if the amount of the photopolymerization initiator added exceeds 10.0 parts by weight, the effect is saturated, which is not good from the perspective of economics.

Furthermore, compounds such as dimethylaminoethyl methacrylate and isopentyl 4-dimethylaminobenzoate may be added to the adhesive as sensitizers for the photopolymerization initiators.

(Filler) Filler is the adhesive layer that crosslinks, hardens, and shrinks due to the irradiation of active energy rays, which reduces the contact area of the adhesive layer with the object being bonded. As a result, the effect of reducing the adhesive's bonding force to the object being bonded is further enhanced.

The strength of the filler at 30% deformation in the micro compression test is 20MPa or more, preferably 20-70MPa, and more preferably 29-70MPa. If the filler's strength at 30% deformation is less than 20MPa, the adhesive layer will not sufficiently reduce the contact area of the adherend. As a result, after being placed under high temperature conditions, even if irradiated with active energy rays, the adhesion force will not be sufficiently reduced, and there is a risk that it will be difficult to peel off the adherend.

The strength of the filler of the present invention at 30% deformation in the micro-compression test is a value measured using a micro-compression tester "MCT-510" (product name) manufactured by Shimadzu Corporation. Specifically, it is measured by the following method. First, the filler to be used is dispersed in ethanol, and then the dispersion of the filler is applied to the sample table of the micro-compression tester (material: SKS material flat plate) and dried to prepare the measurement sample. Next, an independent filler is selected with the optical microscope of MCT-510, and the particle size (diameter) dn (unit: mm) of the selected filler is measured with the particle size measurement optical mark of MCT-510. Next, a pressure piece (diameter 50μm diamond flat piece) was lowered to the selected filler vertex at a constant load speed (9.6841mN/sec) until the maximum load reached 490mN. The load was gradually applied to the filler. The load Pn (unit: N) at the point when the previously measured filler particle size (diameter) was displaced by 30% was calculated based on JIS R 1639-5:2007 by the following formula (1). The test was performed 5 times for each filler, and the average value of the three data excluding the maximum and minimum values was set as the strength at 30% deformation in the micro-compression test. The test was performed in an environment of 23±5℃ and 50±10%RH. In the present invention, the measurement is carried out in an environment of 23°C and 50%RH.

Fn=2.48×Pn/(π・dn ² ) Formula (1)

The filler has a specific strength (hardness), so when the adhesive layer is cross-linked, hardened, and shrunk by the irradiation of active energy rays, the contact area of the adhesive layer with the object being bonded is reduced, thereby further contributing to the effect of reducing the bonding force of the adhesive layer with the object being bonded.

In the relationship between the size of the filler and the thickness of the adhesive layer, when the average particle size of the filler is set to R (μm) and the thickness of the adhesive layer is set to D (μm), the ratio of R to D (R/D) is preferably in the range of 0.20 to 1.00, more preferably 0.40 to 0.80, and even more preferably 0.50 to 0.80. When the ratio of R to D (R/D) is less than 0.20, the adhesive layer may not sufficiently reduce the contact area of the adherend. As a result, after being placed under high temperature conditions, even if the active energy line is irradiated, the adhesion force is not sufficiently reduced, and there is a risk that the adherend may be difficult to peel off. On the other hand, when the ratio of R to D (R/D) exceeds 1.00, the adhesion between the adhesive layer and the sheet-like substrate may deteriorate. In addition, the initial adhesion to the adherend before irradiation with the active energy ray is reduced, and the adherend cannot be fully held, which may affect the processing (position shift or fall off of the adherend).

When the thickness of the adhesive layer is preferably in the range of 10-30 μm, the average particle size of the filler is preferably in the range of 2-30 μm, more preferably 4-24 μm, and even more preferably 5-24 μm. If the average particle size of the filler is in the above range, the effect of reducing the contact area of the adhesive layer with the adherend can be more significantly exhibited. The average particle size referred to in the present invention refers to the median diameter of the 50% diameter value (D 50%) of the cumulative fraction based on volume, obtained by adding a filler and a dispersant to a solvent that does not dissolve or swell the filler and dispersing the particles by ultrasonic dispersion using a laser scattering particle size distribution analyzer (e.g., particle size distribution measuring device "Model LA- ₉₂₀ " manufactured by Horiba, Ltd.), in which the particle size distribution is measured, and the integral volume is calculated from the smallest particle.

The filler is preferably contained in an amount of 1.0 to 62.0 parts by mass, more preferably 1.5 to 50.0 parts by mass, and even more preferably 2.0 to 10.0 parts by mass relative to 100 parts by mass of the acrylic adhesive polymer. If the filler content is less than 1.0 parts by mass, the adhesive layer may not sufficiently reduce the contact area of the adherend. As a result, even if the adherend is exposed to active energy rays after being placed under high temperature conditions, it may be difficult to peel off the adherend. On the other hand, if the filler content exceeds 62.0 parts by mass, the adhesion between the adhesive layer and the sheet-like substrate may deteriorate. In addition, the initial adhesion to the adherend before irradiation with the active energy ray is reduced, and the adherend cannot be fully held, which may affect the processing (position shift or fall off of the adherend). By containing the above filler in the above range, the effect of reducing the contact area of the adhesive layer to the above adherend can be more significantly demonstrated.

In this embodiment, as fillers, crosslinked particles of acrylic polymers widely used in various applications such as coloring ingredients, additives for coatings, optical materials, cosmetics, and molding resins can be used. Examples of methods for producing crosslinked particles of acrylic polymers include a method of producing a polymer in a uniform reaction system, pulverizing and classifying the polymer, a method of finely dispersing the monomer in a reaction solvent such as an aqueous medium that does not substantially dissolve the monomer, and polymerizing the acrylic monomer finely dispersed in the aqueous medium in an oily state to produce the acrylic polymer, and a method of adding acrylic polymer fine particles (seed particles) of the same kind to the acrylic polymer fine particles while polymerizing the acrylic monomer in the heterogeneous system, and reacting the acrylic monomer on the acrylic polymer fine particles so that the acrylic polymer fine particles are impregnated with the acrylic monomer to grow the acrylic polymer fine particles.

Specifically, acrylic monomers such as methyl methacrylate, methyl acrylate, butyl acrylate, butyl methacrylate, etc. are used alone or in combination, and emulsion polymerization is carried out in the presence of a crosslinking agent to synthesize a polymer of acrylic resin with a three-dimensional structure, which is dehydrated and then spray-pulverized for production. As a crosslinking agent, multifunctional vinyl compounds such as divinylbenzene, ethylene glycol dimethacrylate, and trihydroxymethylpropane triacrylate are used. The acrylic resin polymer obtained in this way is a spherical particle with a weight average molecular weight of about 20,000 to 1,000,000. In order to more significantly show the effect of reducing the contact area of the adhesive layer to the above-mentioned adherend, the aspect ratio of the above-mentioned filler is preferably about 0.8 to 1.2.

As the filler, if the strength at 30% deformation in the micro compression test is 20MPa or more, there is no particular limitation on the material, shape, cross-linking, non-cross-linking, etc. In addition to the cross-linked particles of the acrylic polymer, resin particles such as cross-linked (meth)acrylate-styrene copolymer particles, cross-linked polystyrene particles, cross-linked (meth)acrylate butyl ester-styrene copolymer particles, silicone resin particles, or inorganic particles such as aluminum oxide and silicon oxide can also be used. In addition, the active energy ray-curing adhesive used in the present invention may contain a small amount of filler whose strength at 30% deformation in the micro compression test is less than 20MPa, in addition to the filler whose strength at 30% deformation in the micro compression test is 20MPa or more, within the scope that does not impair the effect of the present invention. [Example]

The present invention is more specifically described by the following embodiments, but the present invention is not limited thereto.

1. Preparation of adhesive tape (Example 1) <Thin sheet substrate> As a thin sheet substrate, a PET film (trade name: E5100) with a thickness of 100 μm manufactured by Toyobo Co., Ltd. was prepared. In addition, a corona treatment was applied to the surface of the thin sheet substrate on the side where the adhesive layer was formed to improve adhesion.

<Peeling film> As a peeling film, a 50 μm thick peeling film (trade name: HY-S06) manufactured by Dongshan Film Co., Ltd. was prepared.

<Preparation of acrylic adhesive polymer A> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), and methacrylic acid (MAA) were prepared. These copolymer monomers were mixed in a copolymerization ratio of 2-EHA/2-HEA/MAA = 73 mass%/25 mass%/2 mass%, and a base polymer was synthesized by solution free radical polymerization using ethyl acetate as a solvent. Next, for 100 parts by weight of the solid content of the base polymer, 15 parts by weight of 2-isocyanatoethyl methacrylate (MOI) having an isocyanate group and an active energy line-reactive carbon-carbon double bond as an active energy line-reactive compound was prepared and reacted with a part of the hydroxyl group of 2-HEA to synthesize an acrylic adhesive polymer A having a carbon-carbon double bond in the side chain (solid content concentration: 30% by weight). In addition, in the above reaction, 0.05 parts by weight of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer A was 800,000 as measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). And the carbon-carbon double bond content was 0.84 mmol/g.

<Preparation of adhesive solution (adhesive composition)> 333.3 parts by mass of the acrylic adhesive polymer A solution prepared above (solid content converted to 100 parts by mass) was mixed with 3.0 parts by mass of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) manufactured by Soken Chemical Co., Ltd., and after uniform stirring, diacyl peroxide peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator was mixed in the following proportions: 9.0 parts by mass (3.6 parts by mass as solid content), 1.5 parts by mass of α-aminophenalkoxide-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 0.53 parts by mass (0.4 parts by mass as solid content) of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content concentration: 75% by mass) manufactured by TOSOH as a crosslinking agent were diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30% by mass.

<Adhesive tape preparation> Next, the adhesive solution prepared above was applied to the corona treated surface of the PET film to a dry film thickness of 30 μm, and dried. A peeling film was attached to the adhesive layer and rolled up to prepare an adhesive tape. After the adhesive layer was formed on the sheet-like substrate, it was aged for 120 hours in an environment of 40°C, and the acrylic adhesive polymer was crosslinked with a crosslinking agent to heat harden, thereby preparing an adhesive tape for evaluation.

(Example 2) An adhesive tape was prepared in the same manner as in Example 1 except that the preparation of the adhesive solution was changed as follows.

<Preparation of adhesive solution (adhesive composition)> For the solution of acrylic adhesive polymer A prepared above, 333.3 parts by mass (solid content converted to 100 parts by mass), 42.7 parts by mass of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group: 6, double bond equivalent: 250) manufactured by Negami Industries, and crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) were mixed in the following ratios: 3.0 parts by weight, after uniform stirring, 3.0 parts by weight (1.2 parts by weight in terms of solid content) of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by weight, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator, 1.5 parts by weight of α-aminophenanone-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 1.5 parts by weight of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content: 75% by weight) manufactured by TOSOH as a crosslinking agent were prepared in the following proportions: 0.53 mass parts (0.4 mass parts as solid content) was diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30 mass %.

(Example 3) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer B described below was used as the acrylic adhesive polymer and the preparation of the adhesive solution was changed to the following.

<Preparation of acrylic adhesive polymer B> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. The copolymer monomers were mixed in a copolymerization ratio of 2-EHA/2-HEA = 75 mass%/25 mass%, and a base polymer was synthesized by solution free radical polymerization using ethyl acetate as a solvent. Next, 15 mass parts of 2-isocyanatoethyl methacrylate (MOI) having an isocyanate group and an active energy line-reactive carbon-carbon double bond as an active energy line-reactive compound was prepared for 100 mass parts of the solid content of the base polymer, and reacted with a part of the hydroxyl group of 2-HEA to synthesize an acrylic adhesive polymer B having a carbon-carbon double bond in the side chain (solid content concentration: 30 mass%). In the above reaction, 0.05 parts by weight of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer B was 800,000 as measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran), and the carbon-carbon double bond content was 0.84 mmol/g.

<Preparation of adhesive solution (adhesive composition)> For 333.3 parts by mass of the acrylic adhesive polymer B solution prepared above (converted to 100 parts by mass in terms of solid content), 3.0 parts by mass of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) manufactured by Soken Chemical Co., Ltd. were mixed, and after uniform stirring, diacyl peroxide peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator was mixed in the following proportions: 3.0 parts by mass (1.2 parts by mass as solid content), 1.5 parts by mass of α-aminophenalkoxide-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 0.53 parts by mass (0.4 parts by mass as solid content) of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content concentration: 75% by mass) manufactured by TOSOH as a crosslinking agent were diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30% by mass.

(Example 4) An adhesive tape was prepared in the same manner as in Example 3 except that the preparation of the adhesive solution was changed as follows.

<Preparation of adhesive solution (adhesive composition)> For the solution of acrylic adhesive polymer B prepared above, 333.3 parts by mass (solid content converted to 100 parts by mass), 11.2 parts by mass of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group: 6, double bond equivalent: 250) manufactured by Negami Industries, and crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) were mixed in the following ratios: 3.0 parts by weight, after uniform stirring, 3.0 parts by weight (1.2 parts by weight in terms of solid content) of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by weight, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator, 1.5 parts by weight of α-aminophenanone-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 1.5 parts by weight of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content: 75% by weight) manufactured by TOSOH as a crosslinking agent were prepared in the following proportions: 0.53 mass parts (0.4 mass parts as solid content) was diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30 mass %.

(Example 5) An adhesive tape was prepared in the same manner as in Example 4 except that the amount of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industries was changed to 42.7 parts by mass.

(Example 6) An adhesive tape was prepared in the same manner as in Example 4, except that the amount of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group number: 6, double bond equivalent: 250) manufactured by Negami Industries was changed to 100.0 parts by mass, and the amount of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was changed to 1.5 parts by mass.

(Example 7) An adhesive tape was prepared in the same manner as in Example 6 except that the amount of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industries was changed to 120.0 parts by mass.

(Example 8) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer C described below was used as the acrylic adhesive polymer.

<Preparation of acrylic adhesive polymer C> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. The copolymer monomers were mixed in a copolymerization ratio of 2-EHA/2-HEA = 75 mass%/25 mass%, and a base polymer was synthesized by solution free radical polymerization using ethyl acetate as a solvent. Next, 100 mass parts of the solid content of the base polymer were prepared with 10 mass parts of 2-isocyanatoethyl methacrylate (MOI) having an isocyanate group and an active energy line-reactive carbon-carbon double bond as an active energy line-reactive compound, and reacted with a part of the hydroxyl group of 2-HEA to synthesize an acrylic adhesive polymer C having a carbon-carbon double bond in the side chain (solid content concentration: 30 mass%). In the above reaction, 0.05 parts by weight of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer C was 800,000 as measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran), and the carbon-carbon double bond content was 0.58 mmol/g.

(Example 9) An adhesive tape was prepared in the same manner as in Example 8 except that the preparation of the adhesive solution was changed as follows.

<Preparation of adhesive solution (adhesive composition)> For the solution of acrylic adhesive polymer C prepared above, 333.3 parts by mass (solid content converted to 100 parts by mass), 42.7 parts by mass of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group: 6, double bond equivalent: 250) manufactured by Negami Industries, and crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) were mixed in the following ratios: 3.0 parts by weight, after uniform stirring, 3.0 parts by weight (1.2 parts by weight in terms of solid content) of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by weight, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator, 1.5 parts by weight of α-aminophenanone-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 1.5 parts by weight of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content: 75% by weight) manufactured by TOSOH as a crosslinking agent were prepared in the following proportions: 0.53 mass parts (0.4 mass parts as solid content) was diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30 mass%.

(Example 10) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer D described below was used as the acrylic adhesive polymer and the preparation of the adhesive solution was changed to the following.

<Preparation of acrylic adhesive polymer D> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. The copolymer monomers were mixed in a copolymerization ratio of 2-EHA/2-HEA = 55 mass%/45 mass%, and a base polymer was synthesized by solution free radical polymerization using ethyl acetate as a solvent. Next, 35 mass parts of 2-isocyanatoethyl methacrylate (AOI) having an isocyanate group and an active energy line-reactive carbon-carbon double bond as an active energy line-reactive compound was prepared for 100 mass parts of the solid content of the base polymer, and reacted with a part of the hydroxyl group of 2-HEA to synthesize an acrylic adhesive polymer D having a carbon-carbon double bond in the side chain (solid content concentration: 30 mass%). In the above reaction, 0.05 parts by weight of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer D was 700,000 as measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). The carbon-carbon double bond content was 1.83 mmol/g.

<Preparation of adhesive solution> For the solution of acrylic adhesive polymer D prepared above, 333.3 parts by mass (solid content converted to 100 parts by mass) was mixed with 3.0 parts by mass of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) manufactured by Soken Chemical Co., Ltd., and after uniform stirring, diacyl peroxide peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1℃) manufactured by NOF Corporation as a thermal polymerization initiator was mixed in the following proportions: 0.3 parts by mass (0.12 parts by mass as solid content), 1.5 parts by mass of α-aminophenalkoxide-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 0.53 parts by mass (0.4 parts by mass as solid content) of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content concentration: 75% by mass) manufactured by TOSOH as a crosslinking agent were diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30% by mass.

(Example 11) An adhesive tape was prepared in the same manner as in Example 10 except that the preparation of the adhesive solution was changed as follows.

<Preparation of adhesive solution (adhesive composition)> For the solution of acrylic adhesive polymer D prepared above, 333.3 parts by mass (solid content converted to 100 parts by mass), 42.7 parts by mass of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group: 6, double bond equivalent: 250) manufactured by Negami Industries, and crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) were mixed in the following ratios: 3.0 parts by weight, after uniform stirring, 3.0 parts by weight (1.2 parts by weight in terms of solid content) of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by weight, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator, 1.5 parts by weight of α-aminophenanone-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 1.5 parts by weight of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content: 75% by weight) manufactured by TOSOH as a crosslinking agent were prepared in the following proportions: 0.53 mass parts (0.4 mass parts as solid content) was diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30 mass%.

(Example 12) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer E described below was used as the acrylic adhesive polymer and the preparation of the adhesive solution was changed to the following.

<Preparation of acrylic adhesive polymer E> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA) and 2-hydroxyethyl acrylate (2-HEA) were prepared. The copolymer monomers were mixed in a copolymerization ratio of 2-EHA/2-HEA = 78 mass%/22 mass%, and a base polymer was synthesized by solution free radical polymerization using ethyl acetate as a solvent. Next, 7 mass parts of 2-isocyanatoethyl methacrylate (MOI) having an isocyanate group and an active energy line-reactive carbon-carbon double bond as an active energy line-reactive compound was prepared for 100 mass parts of the solid content of the base polymer, and reacted with a part of the hydroxyl group of 2-HEA to synthesize an acrylic adhesive polymer E having a carbon-carbon double bond in the side chain (solid content concentration: 30 mass%). In the above reaction, 0.05 parts by weight of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer E was 800,000 as measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran). The carbon-carbon double bond content was 0.41 mmol/g.

<Preparation of adhesive solution> For the solution of acrylic adhesive polymer E prepared above, 333.3 parts by mass (solid content converted to 100 parts by mass), 50.0 parts by mass of urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group: 6, double bond equivalent: 250) manufactured by Negami Industries, Ltd. and crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55MPa) were mixed in the following ratios: 3.0 parts by weight, after uniform stirring, 3.0 parts by weight (1.2 parts by weight in terms of solid content) of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by weight, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator, 1.5 parts by weight of α-aminophenanone-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 1.5 parts by weight of isocyanate-based crosslinking agent A (trade name: Coronate L, solid content: 75% by weight) manufactured by TOSOH as a crosslinking agent were prepared in the following proportions: 0.53 mass parts (0.4 mass parts as solid content) was diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 30 mass%.

(Example 13) An adhesive tape was prepared in the same manner as in Example 5 except that 1.5 parts by weight of hindered phenol antioxidant A (trade name: Irganox 1010) manufactured by BASF Corporation of Japan was further added to the adhesive solution as an antioxidant.

(Example 14) An adhesive tape was prepared in the same manner as in Example 5 except that the amount of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, degree of crosslinking: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was changed to 1.5 parts by mass.

(Example 15) An adhesive tape was prepared in the same manner as in Example 5 except that the amount of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, degree of crosslinking: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was changed to 50.0 parts by mass.

(Example 16) An adhesive tape was prepared in the same manner as in Example 5 except that the amount of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, degree of crosslinking: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was changed to 61.2 parts by mass.

(Example 17) An adhesive tape was prepared in the same manner as in Example 5 except that the crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was replaced with the crosslinked acrylic filler B (trade name: Chemisnow MX-1000, average particle size: 10 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 56 MPa) manufactured by Soken Chemical Co., Ltd.

(Example 18) An adhesive tape was prepared in the same manner as in Example 5, except that the crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was replaced with the crosslinked acrylic filler C (trade name: Chemisnow MX-500, average particle size: 5 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 56 MPa) manufactured by Soken Chemical Co., Ltd., and the thickness of the adhesive layer was changed to 25 μm.

(Example 19) An adhesive tape was prepared in the same manner as in Example 5 except that the dry thickness of the adhesive layer was changed to 25 μm.

(Example 20) An adhesive tape was prepared in the same manner as in Example 5 except that the amount of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was changed to 0.3 parts by mass (0.12 parts by mass in terms of solid content).

(Example 21) An adhesive tape was prepared in the same manner as in Example 5, except that the amount of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was changed to 50.0 parts by mass (20.0 parts by mass in terms of solid content).

(Example 22) An adhesive tape was prepared in the same manner as in Example 4 except that the amount of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was changed to 75.8 parts by mass (30.3 parts by mass in terms of solid content).

(Example 23) An adhesive tape was prepared in the same manner as in Example 5 except that the diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was replaced with the peroxyester-based peroxide B (trade name: Perbutyl O, solid content: 100% by mass, 10-hour half-life temperature: 72.1°C) manufactured by NOF Corporation and the mixing amount was set to 1.2 parts by mass.

(Example 24) An adhesive tape was prepared in the same manner as in Example 5 except that the diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was replaced with the dialkyl peroxide-based peroxide C (trade name: Perbutyl D, solid content: 100% by mass, 10-hour half-life temperature: 123.7°C) manufactured by NOF Corporation and the mixing amount was set to 1.2 parts by mass.

(Example 25) An adhesive tape was prepared in the same manner as in Example 4 except that the diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was replaced with the non-cyanide-based polymerization initiator A (trade name: OTAZO-15, solid content: 100% by mass, 10-hour half-life temperature: 61°C) manufactured by Otsuka Chemical Co., Ltd., and the mixing amount was set to 0.6 parts by mass.

(Example 26) An adhesive tape was prepared in the same manner as in Example 4 except that the diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was replaced with an azo-based polymerization initiator B (trade name: AIBN, solid content: 100% by mass, 10-hour half-life temperature: 65°C) manufactured by Otsuka Chemical Co., Ltd. and the amount thereof was set to 0.6 parts by mass.

(Example 27) An adhesive tape was prepared in the same manner as in Example 5 except that the α-aminophenanone photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. was replaced with the α-hydroxyphenanone photopolymerization initiator B (trade name: Omnirad 184) manufactured by IGM Resins B.V.

(Example 28) An adhesive tape was prepared in the same manner as in Example 5 except that the α-aminophenanone-based photopolymerization initiator A (trade name: Omnirad 369) manufactured by IGM Resins B.V. was replaced with the bisacylphosphine oxide-based photopolymerization initiator C (trade name: Omnirad 819) manufactured by IGM Resins B.V.

(Example 29) An adhesive tape was prepared in the same manner as in Example 24 except that urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, number of functional groups: 6, double bond equivalent: 250) manufactured by Negami Industries was replaced with urethane acrylate oligomer B (trade name: Art Resin UN-904, weight average molecular weight: 4,900, number of functional groups: 10, double bond equivalent: 490) manufactured by Negami Industries.

(Example 30) An adhesive tape was prepared in the same manner as in Example 5, except that urethane acrylate oligomer A (trade name: Art Resin UN-3320HA, weight average molecular weight: 1,500, functional group number: 6, double bond equivalent: 250) manufactured by Negami Industries was replaced by urethane acrylate oligomer C (trade name: UV-7000B, weight average molecular weight: 3,500, functional group number: 2.5, double bond equivalent: 1,400) manufactured by Mitsubishi Chemical Corporation, and the amount of diacyl peroxide-based peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation was changed to 9.0 parts by mass (3.6 parts by mass in terms of solid content).

(Example 31) An adhesive tape was prepared in the same manner as in Example 5 except that the weight average molecular weight of the acrylic adhesive polymer B was adjusted to 300,000 by controlling the concentration of the initiator. The carbon-carbon double bond content of the acrylic adhesive polymer F was 0.84 mmol/g.

(Example 32) An adhesive tape was prepared in the same manner as in Example 5 except that the weight average molecular weight of the acrylic adhesive polymer B was adjusted to 1.5 million by controlling the initiator concentration and polymerization time. The carbon-carbon double bond content of the acrylic adhesive polymer G was 0.82 mmol/g.

(Example 33) An adhesive tape was prepared in the same manner as in Example 5 except that the crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was replaced with the crosslinked acrylic filler G (trade name: Techpolymer BM30X-12, average particle size: 12 μm, strength at 30% deformation in micro compression test: 29 MPa) manufactured by Sekisui Chemicals Co., Ltd.

(Example 34) An adhesive tape was prepared in the same manner as in Example 5 except that the crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was replaced with the crosslinked acrylic filler D (trade name: Art Pearl J-4P, average particle size: 2.2 μm, crosslinking degree: low, strength at 30% deformation in micro compression test: 70 MPa) manufactured by Negami Industries, Ltd., and the dry thickness of the adhesive layer was changed to 10 μm.

(Comparative Example 1) An adhesive tape was prepared in the same manner as in Example 2 except that crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. and diacyl peroxide peroxide A (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation were not added.

(Comparative Example 2) An adhesive tape was prepared in the same manner as in Example 5 except that crosslinked acrylic filler A manufactured by Soken Chemical Co., Ltd. (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) and diacyl peroxide peroxide A manufactured by NOF Corporation (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) were not added.

(Comparative Example 3) An adhesive tape was prepared in the same manner as in Example 5 except that the acrylic adhesive polymer H without a carbon-carbon double bond was used as the acrylic adhesive polymer.

<Preparation of acrylic adhesive polymer H> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA), methyl acrylate (MA), and methacrylic acid (MAA) were prepared. These copolymer monomers were mixed in a copolymerization ratio of 2-EHA/2-HEA/MA/MAA=10 mass%/10 mass%/78 mass%/2 mass%, and acrylic adhesive polymer H (solid concentration: 35 mass%) was synthesized by solution free radical polymerization using ethyl acetate as a solvent. In addition, in the above reaction, 0.05 mass parts of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer H was 800,000 as measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran).

(Comparative Example 4) An adhesive tape was prepared in the same manner as in Example 5 except that crosslinked acrylic filler A manufactured by Soken Chemical Co., Ltd. (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) was not added.

(Comparative Example 5) An adhesive tape was prepared in the same manner as in Example 5 except that the cross-linked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, cross-linking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was replaced with the cross-linked urethane filler A (trade name: JB-400CB, average particle size: 15 μm, strength at 30% deformation in micro compression test: 8.5 MPa) manufactured by Negami Industries Co., Ltd.

(Comparative Example 6) An adhesive tape was prepared in the same manner as in Example 27 except that diacyl peroxide-based peroxide A manufactured by NOF Corporation (trade name: Nyper BMT-K40, solid content: 40% by mass, 10-hour half-life temperature: 73.1°C) was not added.

(Comparative Example 7) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer I without a carbon-carbon double bond was used as the acrylic adhesive polymer and the preparation of the adhesive solution was changed to the following.

<Preparation of acrylic adhesive polymer I> As copolymer monomer components, 2-ethylhexyl acrylate (2-EHA), n-butyl acrylate (BA), and 2-hydroxyethyl acrylate (2-HEA) were prepared. The copolymer monomers were mixed in a copolymerization ratio of 2-EHA/BA/2-HEA = 20 mass %/75 mass %/5 mass %, and ethyl acetate was used as a solvent to synthesize acrylic adhesive polymer I (solid concentration: 35 mass %) by solution free radical polymerization. In addition, in the above reaction, 0.05 mass parts of hydroquinone monomethyl ether was used as a polymerization inhibitor. The weight average molecular weight of the synthesized acrylic adhesive polymer I was measured by gel permeation chromatography (GPC, solvent: tetrahydrofuran) and was 800,000.

<Preparation of adhesive solution> For the solution of acrylic adhesive polymer I prepared above, 303.0 parts by mass (100 parts by mass based on solid content) were mixed with 100 parts by mass of multifunctional acrylate A (epoxyisocyanuric acid triacrylate, trade name: A-9300, molecular weight: 423, functional group: 3, double bond equivalent: 141) manufactured by Shin-Nakamura Chemical Industry Co., Ltd. and 2.0 parts by mass of crosslinked acrylic filler D (trade name: Art Pearl J-4P, average particle size: 2.2μm, crosslinking degree: low, strength at 30% deformation in micro compression test: 70MPa) manufactured by Negami Industry Co., Ltd., and after uniformly stirring, IGM Resins as a photopolymerization initiator were mixed with the following ratio: 1.0 parts by mass of α-hydroxyphenanone photopolymerization initiator D (trade name: Omnirad 184) manufactured by B.V. and 4.0 parts by mass of isocyanate crosslinking agent B (trade name: Coronate L, solid content concentration: 75% by mass) manufactured by TOSOH as a crosslinking agent (3.0 parts by mass based on solid content) were diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 33% by mass.

(Comparative Example 8) An adhesive tape was prepared in the same manner as in Comparative Example 7 except that the crosslinked acrylic filler D (trade name: Art Pearl J-4P, average particle size: 2.2 μm, crosslinking degree: low, strength at 30% deformation in micro compression test: 70 MPa) manufactured by Negami Industries was replaced with the crosslinked acrylic filler E (trade name: Art Pearl J-7P, average particle size: 6 μm, crosslinking degree: low, strength at 30% deformation in micro compression test: 69 MPa) manufactured by Negami Industries, and the blending amount was set to 20 parts by mass.

(Comparative Example 9) An adhesive tape was prepared in the same manner as in Comparative Example 8 except that the amount of crosslinked acrylic filler E (trade name: Art Pearl J-7P, average particle size: 6μm, crosslinking degree: low, strength at 30% deformation in micro compression test: 69MPa) manufactured by Negami Industries was set to 60 parts by mass.

(Comparative Example 10) An adhesive tape was prepared in the same manner as in Comparative Example 9 except that the crosslinked acrylic filler E (trade name: Art Pearl J-7P, average particle size: 6μm, crosslinking degree: low, strength at 30% deformation in micro compression test: 69MPa) manufactured by Negami Industries was replaced with the crosslinked acrylic filler F (trade name: Art Pearl GR-600 transparent, average particle size: 10μm, crosslinking degree: medium, strength at 30% deformation in micro compression test: 60MPa) manufactured by Negami Industries.

(Comparative Example 11) An adhesive tape was prepared in the same manner as in Comparative Example 10 except that the amount of crosslinked acrylic filler F (trade name: Art Pearl GR-600 transparent, average particle size: 10 μm, degree of crosslinking: medium, strength at 30% deformation in micro compression test: 60 MPa) manufactured by Negami Industries was set to 80 parts by mass.

(Comparative Example 12) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer was not used and the preparation of the adhesive solution was changed as follows.

<Preparation of adhesive solution> For 167 parts by mass (solid content converted to 100 parts by mass) of urethane prepolymer A (trade name: CYABINE SH-101, hydroxyl value: 18 mgKOH/g, solid content concentration: 60%) manufactured by TOYO CHEM, multifunctional acrylate B (dipentaerythritol polyacrylate [a mixture of 5-functional and 6-functional acrylates], trade name: A-9550, hydroxyl value: 53 mgKOH/g, double bond equivalent [mass per 1 mol of double bond prepolymer]: 110 g/mol) manufactured by Shin-Nakamura Chemical Industry Co., Ltd. was mixed in the following ratio: 75 parts by weight of the mixture was stirred uniformly, and then mixed in the following proportions: 1.5 parts by weight of peroxydicarbonate peroxide D (trade name: PeroylTCP, solid content: 100% by weight, 10-hour half-life temperature: 40.8°C) manufactured by NOF Corporation as a thermal polymerization initiator, 2.0 parts by weight of acylphosphine oxide photopolymerization initiator E (trade name: Omnirad TPO H) manufactured by IGM Resins B.V. as a photopolymerization initiator, 5.0 parts by weight of ionic liquid antistatic agent A (trade name: FC4400) manufactured by 3M Japan as an antistatic agent, and 1.5 parts by weight of isocyanate crosslinking agent B (trade name: Coronate 100) manufactured by TOSOH Corporation as a crosslinking agent. L-45E, solid content concentration: 45% by mass 32.9 parts by mass (14.8 parts by mass as solid content) was diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 33% by mass.

(Comparative Example 13) An adhesive tape was prepared in the same manner as in Comparative Example 12 except that the amount of peroxydicarbonate peroxide D (trade name: PeroylTCP, solid content: 100 mass %, 10-hour half-life temperature: 40.8°C) manufactured by NOF Corporation was changed to 10.0 mass parts, and the amount of isocyanate crosslinking agent B (trade name: Coronate L-45E, solid content: 45 mass %) manufactured by TOSOH Corporation was changed to 49.3 mass parts (22.2 mass parts in terms of solid content).

(Comparative Example 14) An adhesive tape was prepared in the same manner as in Example 1 except that the acrylic adhesive polymer was not used and the preparation of the adhesive solution was changed as follows.

<Preparation of adhesive solution> Urethane prepolymer B (trade name: CYABINE SH-109, solid content concentration 64% by mass) manufactured by TOYO CHEM was mixed with 75 parts by mass of multifunctional acrylate C (pentaerythritol tetraacrylate, trade name: SR295, functional group: 4, double bond equivalent: 88) manufactured by CYTOMER, and after uniform stirring, diacyl peroxide peroxide A (trade name: Nyper BMT-K40, solid content concentration: 40% by mass, 10-hour half-life temperature: 73.1°C) manufactured by NOF Corporation as a thermal polymerization initiator was mixed in the following proportions: 9.38 parts by mass (3.75 parts by mass as solid content), 2 parts by mass of acylphosphine oxide-based photopolymerization initiator E (trade name: Omnirad TPO H) manufactured by IGM Resins B.V. as a photopolymerization initiator, and 32.9 parts by mass (14.8 parts by mass as solid content) of isocyanate crosslinking agent B (trade name: Coronate L-45E, solid content concentration: 45% by mass) manufactured by TOSOH as a crosslinking agent were diluted with ethyl acetate and stirred to prepare an adhesive solution with a solid content concentration of 33% by mass.

(Comparative Example 15) An adhesive tape was prepared in the same manner as in Comparative Example 14 except that the amount of isocyanate crosslinking agent B (trade name: Coronate L-45E, solid content: 45% by mass) manufactured by TOSOH was changed to 49.3 parts by mass (22.2 parts by mass in terms of solid content).

(Comparative Example 16) An adhesive tape was prepared in the same manner as in Comparative Example 15, except that 2.0 parts by weight of crosslinked acrylic filler A (trade name: Chemisnow MX-2000, average particle size: 20 μm, crosslinking degree: standard, strength at 30% deformation in micro compression test: 55 MPa) manufactured by Soken Chemical Co., Ltd. was further mixed into the adhesive solution.

2. Evaluation method of adhesive tape The adhesive tapes prepared in Examples 1 to 34 and Comparative Examples 1 to 16 were cut into pieces 25 mm wide and used as test pieces.

2.1 Initial adhesion test For each test piece of the above adhesive tape, an adhesion test (peeling adhesion test) was performed on the glass plate in normal state (before heat treatment) according to the method described in Adhesive tape and adhesive sheet test method (JIS Z 0237 (2009)).

Specifically, the peeling film of the adhesive tape was peeled off and attached to a glass plate with a fully cleaned surface without trapping bubbles. After being pressed by a roller with a mass of 2000g at a speed of 5mm/second, it was placed in an environment of temperature 23℃ and humidity 50%RH for 20 minutes as a test sample. Then, a tensile tester was used to peel off the glass plate in the 90° direction at a speed of 300mm/minute to measure the initial adhesion to the glass plate. In addition, the environment during attachment and measurement was set to a temperature of 23℃ and a humidity of 50%RH.

The initial adhesion in normal state is not particularly limited, but based on the ease of attachment to the adherend and the retention of the adherend during processing, it is preferably 0.5N/10mm or more. If the adhesion increases when placed under high temperature conditions, it is more preferably set in the range of 0.5N/10mm to 3.5N/10mm.

The initial adhesion under normal conditions is evaluated based on the following criteria, with ○ being considered acceptable.

○: 0.5N/10mm or more ×: Less than 0.5N/10mm

2.2 Adhesion test after heat treatment For each test piece of the above adhesive tape, the adhesion test (peeling adhesion test) after heat treatment on the glass plate was carried out in accordance with the method described in the adhesive tape and adhesive sheet test method (JIS Z 0237 (2009)) in the same way as the initial adhesion test.

Specifically, after peeling off the peeling film of the adhesive tape, it is attached to the fully cleaned glass plate in a way that does not trap bubbles, and then a roller with a mass of 2000g is pressed back and forth once at a speed of 5mm/second. Then, the glass plate with the adhesive tape attached is stored under the following three added treatment conditions and taken out, and placed in an environment of temperature 23℃ and humidity 50%RH for more than 2 hours as a test sample. Then, using a tensile testing machine, the glass plate is peeled off at a speed of 300mm/minute in the 90° direction, and the adhesion of the glass plate after heat treatment is measured. In addition, the environment during attachment and measurement is set to a temperature of 23℃ and a humidity of 50%RH.

Heat treatment condition (1): 165°C for 1 hour Heat treatment condition (2): 165°C for 3 hours Heat treatment condition (3): 200°C for 1 hour

As for the adhesion after heat treatment, it is preferably 0.5N/10mm or more from the viewpoint of maintaining the adherend during processing under high temperature conditions. If the adhesion reduction effect of subsequent active energy ray irradiation is taken into consideration, it is more preferably set in the range of 0.5N/10mm~2.5N/10mm.

The adhesion after heat treatment is evaluated according to the following criteria, and ○ is considered acceptable.

○: 0.5N/10mm or more ×: Less than 0.5N/10mm

2.3 Adhesion test after ultraviolet (UV) irradiation Using the test samples prepared in 2.1 (before heat treatment: normal state) and 2.2 (after heat treatment: 3 conditions), the adhesion test (peeling adhesion test) after ultraviolet (UV) irradiation on the glass plate was carried out in the same manner as the initial adhesion test according to the method described in Adhesive tapes and adhesive sheets test methods (JIS Z 0237 (2009)).

Specifically, for the test samples prepared in 2.1 (before heat treatment) and the test samples prepared in 2.2 (after heat treatment), a high-pressure mercury lamp (model H04-L21) manufactured by EYE GRAPHIC was used to irradiate ultraviolet light (UV) from the side where the adhesive tape was attached at a cumulative light amount of 500mJ/ ^cm2 . Then, a tensile tester was used to peel off the glass plate in the 90° direction at a speed of 300mm/min, and the adhesion to the glass plate after ultraviolet light (UV) irradiation was measured. In addition, the environment during attachment and measurement was set to a temperature of 23℃ and a humidity of 50%RH.

In the normal state before heat treatment, as the adhesive force after ultraviolet (UV) irradiation, it is preferably as small as possible in consideration of the phenomenon of increased adhesive force when placed under high temperature conditions. Specifically, it is preferably set to 0.10N/10mm or less, and more preferably set to 0.05N/10mm or less.

The adhesion after UV irradiation in normal state before heat treatment was evaluated according to the following judgment criteria, and the evaluation of ○ was qualified.

○: 0.10N/10mm or less ×: more than 0.10N/10mm

After the heat treatment, the adhesion after ultraviolet (UV) irradiation is preferably 0.25N/10mm or less (lower limit: 0N/10mm), and more preferably 0.10N/10mm or less, if the degree of easy debonding (peeling) is considered without contaminating or damaging the adherend.

The adhesion after heat treatment and UV irradiation was evaluated according to the following criteria, with ○ being considered acceptable.

○: 0.25N/10mm or less ×: more than 0.25N/10mm

2.4 Evaluation of the contamination of the glass plate surface When measuring the adhesion after UV irradiation in 2.3 above, the contamination of the peel-off plate surface after removing each adhesive tape was evaluated.

Specifically, the surface of the glass substrate was observed visually and under a microscope, and the state of the adhesive composition residue area relative to the adhesive tape attachment area was evaluated according to the following criteria. ◎ or ○ was considered acceptable.

◎: The total area of the residue is less than 1% of the area of the adhesive tape ○: The total area of the residue is 1% or more and less than 5% of the area of the adhesive tape △: The total area of the residue is 5% or more and less than 25% of the area of the adhesive tape ×: The total area of the residue is 25% or more of the area of the adhesive tape

3. Overall evaluation of adhesive tapes The overall evaluation of adhesive tapes was evaluated based on the following criteria. An evaluation of A or B indicates that the adhesive tapes are usable for temporary fixing of electronic components in practice and are considered acceptable.

A: Adhesion rating is all ○, and contamination rating is all ◎ B: Adhesion rating is all ○, and contamination rating is at the qualified level and includes ○ C: Adhesion rating is all ○, and contamination rating includes △, or adhesion rating includes × and contamination rating is △~◎ D: Regardless of adhesion rating, contamination rating includes ×

Tables 1 to 6 show the composition of the adhesive layer of the adhesive tape. Tables 7 to 12 show the characteristics and evaluation results of the adhesive layer of the adhesive tape.

As shown in Tables 7 to 10, the adhesive tapes of Examples 1 to 34, in which the adhesive layer contains an acrylic adhesive polymer having a carbon-carbon double bond and a functional group, a photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent, and a filler having a strength of 20 MPa or more at 30% deformation in a micro-compression test, have obtained good results in all evaluation items of initial adhesion, adhesion after ultraviolet (UV) irradiation, and contamination of the glass plate surface after debonding under any condition. It can be seen that the adhesive tape of this embodiment is used as an adhesive tape for temporary fixing of electronic parts that must be processed under high temperature conditions of about 165 to 200°C, for example.

In contrast, as shown in Tables 11-12, the adhesive layer did not meet the requirements of the adhesive tapes of Comparative Examples 1-16 of the present embodiment, and any evaluation result of the evaluation items of initial adhesion, adhesion after ultraviolet (UV) irradiation, and contamination state of the glass plate surface after debonding was confirmed to be worse than that of the adhesive tapes of Examples 1-34.

Specifically, the adhesive tapes of Comparative Examples 1 and 2, which do not contain fillers and thermal polymerization initiators in the adhesive layer, have a significantly increased adhesive force during the heat treatment under more severe heat treatment conditions 2 and 3, compared with Examples 2 and 5. Therefore, even after subsequent irradiation with ultraviolet rays (UV), the adhesive force is not sufficiently reduced. In addition, the adhesive tape of Comparative Example 1 clearly shows contamination on the surface of the glass plate.

The adhesive tape of Comparative Example 3, in which an acrylic adhesive polymer without a carbon-carbon double bond is used as the acrylic adhesive polymer in the adhesive layer, has a significantly increased adhesive force under any heat treatment condition compared with Examples 2, 5, 9, 11, 31, and 32. Therefore, even after subsequent irradiation with ultraviolet rays (UV), the adhesive force is not sufficiently reduced. In addition, the adhesive tape of Comparative Example 1 clearly shows contamination on the surface of the glass plate.

The adhesive tape of Comparative Example 4, in which the adhesive layer does not contain fillers, does not sufficiently reduce the adhesive force even when irradiated with ultraviolet rays (UV) in the more severe heat treatment conditions 2 and 3 compared with Example 5. In addition, slightly more contamination was observed on the surface of the glass plate.

The adhesive tape of Comparative Example 5, in which the cross-linked urethane filler in the adhesive layer has a strength of 8.5 MPa, which is lower than 20 MPa, at 30% deformation in the micro-compression test, does not sufficiently reduce the adhesive force even when irradiated with ultraviolet rays (UV) in the more severe heat treatment conditions 2 and 3, compared with Example 5.

The adhesive tape of Comparative Example 6, in which the adhesive layer does not contain a thermal polymerization initiator, has a higher adhesive force during the heat treatment under more severe heat treatment conditions 2 and 3 than Example 5. Therefore, even after subsequent ultraviolet (UV) irradiation, the adhesive force is not sufficiently reduced. In heat treatment condition 3, slightly more contamination is observed on the surface of the glass plate.

Although the adhesive layer contains fillers, the adhesive tapes of Comparative Examples 7 to 11, which use an acrylic adhesive polymer without a carbon-carbon double bond as the acrylic adhesive polymer, use a multifunctional acrylate instead of a urethane acrylate oligomer, and do not contain a thermal polymerization initiator, have a significantly increased adhesive force during the heat treatment under any heat treatment condition compared to the Example, so the adhesive force is not sufficiently reduced even after subsequent ultraviolet (UV) irradiation. In addition, contamination of the glass plate surface is clearly observed.

Although the adhesive layer contains fillers, the adhesive tapes of Comparative Examples 12 to 15, which use urethane prepolymers and multifunctional acrylates instead of acrylic adhesive polymers and urethane acrylate oligomers and do not contain fillers, clearly observed contamination of the glass plate surface under any heat treatment condition compared with the Example. It was also observed that the adhesive force was not sufficiently reduced even after irradiation with ultraviolet rays (UV). Furthermore, in the adhesive tapes of Comparative Examples 13 to 15, the initial adhesive force was reduced under any heat treatment condition.

Compared with the adhesive tape of Comparative Example 15, which contains fillers, the adhesive force of Comparative Example 16 after ultraviolet (UV) irradiation is within the acceptable level under any heat treatment condition, but the initial adhesive force is low, and contamination of the glass plate surface is clearly observed.

Claims (6)

An adhesive tape having a sheet-like substrate through which active energy rays can pass and an adhesive layer disposed on the surface of the sheet-like substrate, wherein the adhesive layer contains an acrylic adhesive polymer having a carbon-carbon double bond and a functional group, a photopolymerization initiator, a thermal polymerization initiator, a crosslinking agent that reacts with the functional group, and a filler, wherein the functional group is at least one functional group selected from a hydroxyl group, a carboxyl group, and a glycidyl group, and the amount of the crosslinking agent is 0.01 to 5.00 parts by weight relative to 100 parts by weight of the acrylic adhesive polymer. The filler has a low thermal conductivity and a low thermal conductivity in a micro-compression test. The strength at 30% deformation is above 20MPa, the average particle size is 2~30μm, the average particle size is set as R (μm), and when the thickness of the adhesive layer is set as D (μm), the ratio of R to D (R/D) is in the range of 0.20~1.00, and the filler is contained in the range of 1.5~61.2 mass parts relative to 100 mass parts of acrylic adhesive polymer having carbon-carbon double bonds and functional groups, and the carbon-carbon double bond content of the acrylic adhesive polymer having carbon-carbon double bonds and functional groups is in the range of 0.40~1.85mmol/g. The adhesive tape of claim 1 contains the aforementioned thermal polymerization initiator in an amount ranging from 0.1 to 31.0 parts by mass relative to 100 parts by mass of the acrylic adhesive polymer having a carbon-carbon double bond and a functional group. The adhesive tape of claim 1 or 2, wherein the adhesive layer comprises an oligomer having a carbon-carbon double bond. As in the adhesive tape of claim 3, the aforementioned oligomer having carbon-carbon double bonds contains more than 2 carbon-carbon double bonds, the carbon-carbon double bond equivalent is in the range of 250 to 1,400, and the weight average molecular weight is in the range of 1,500 to 4,900. The adhesive tape of claim 3, wherein the aforementioned oligomer having a carbon-carbon double bond is contained in an amount of up to 120 parts by mass relative to 100 parts by mass of the aforementioned acrylic adhesive polymer having a carbon-carbon double bond and a functional group. As in any one of claim items 1 to 3, the adhesive tape is an adhesive tape for temporarily fixing electronic components.