JP4715517B2 - Microcapsule type adhesive composition - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention provides a microcapsule type adhesive composition capable of imparting a loosening prevention effect and adhesion (hereinafter referred to as a loosening prevention) by preliminarily applying to a joint surface of a screwed portion such as a screw, bolt or nut. It is about.

  Various types of anti-loosening adhesives that are applied in advance to a threaded surface (thread) of a screwing member such as a screw, bolt, or nut have been known (Patent Documents 1 to 7). As a typical example of these loosening prevention adhesives, a microcapsule enclosing one component of a two-component curable epoxy resin (epoxy resin curing agent or epoxy resin curing agent such as amine), the other component and a binder component There is known a liquid microcapsule type adhesive in which is dissolved or dispersed in an organic solvent or a solvent such as water. These liquid adhesives are generally applied to the screwing surface (thread) of the screwing member, and then dried and solidified to form an apparent solid film, thereby forming a screwing member with an adhesive layer. Convenience such as stability during storage and ease of handling can be obtained.

  However, these conventional microcapsule type adhesives have insufficient adhesion to the threaded surface (thread) of the threaded member, or the adhesive applied to the threaded surface deteriorates over time and tightens. The problem caused by the low storage stability such as an increase in the insertion torque was caused, and further, the adhesive using the organic solvent had the disadvantage that it might cause environmental pollution. For example, when the adhesive layer is formed on the screw member with an adhesive using polyvinyl alcohol as the binder resin, there is a disadvantage that the performance cannot be prevented because it swells with moisture or the like.

In addition, when the adhesive layer is formed with an adhesive using a polyacetal resin as a binder resin, the above-mentioned problems are solved, but there is a tendency that tightening resistance increases due to deterioration over time, and screw assembly is difficult. Problems such as difficulty may occur. Furthermore, when polyvinyl alcohol or polyacetal resin is used as the binder resin, since these binder resins have low gas permeability, only the surface is dried in the drying process after the adhesive is applied to the screwed portion. When the solvent is formed and the solvent remains inside, the coating film becomes uneven and the appearance is liable to be impaired.
Japanese Examined Patent Publication No. 45-11051 Japanese Examined Patent Publication No. 52-46399 JP-A-2-308776 JP-A-53-11883 Japanese Patent Laid-Open No. 7-331187 Japanese Patent Laid-Open No. 10-130587 JP 2003-194032 A

The present invention solves the above problems, is excellent in preservability as an adhesive composition, does not drip when applied during screwing, and does not cause coating unevenness when dried The purpose is to provide. Furthermore, the present invention is a microcapsule type in which the dried coating film after coating is in close contact with a metal surface and encapsulates an epoxy resin with little increase in tightening torque due to change over time, and an aqueous loosening prevention adhesive composition The purpose is to provide goods.
Furthermore, this invention provides the screwing member which has the precoat adhesive layer for loosening prevention formed with the said adhesive composition, and its manufacturing method.

As a result of intensive studies, the present inventors have obtained the knowledge that the above-mentioned problems can be solved by combining predetermined microcapsules, a binder resin emulsion having a pH of 6 to 13, an amine-based curing agent, and a hydrolyzed neutralized product. .
Accordingly, the present invention provides a microcapsule (A) containing an epoxy resin as a core material and an aldehyde resin or urea resin as a wall material; an emulsion (B) containing a binder resin having an emulsifying ability and having a pH of 6 to 13; Or water-dispersible amine-based curing agent (C); and hydrolyzed neutralized product of copolymer of alkyl vinyl ether and maleic anhydride, or alkyldiene crosslinking of copolymer of alkyl vinyl ether and maleic anhydride There is provided a microcapsule type adhesive composition comprising a product hydrolyzed neutralized product (D).
Further, according to the present invention, there is provided a pre-coating adhesive layer for preventing loosening, characterized in that the pre-coated adhesive layer is formed by applying the microcapsule-type adhesive composition to the surface of the screw member and drying it. Provided is a method for manufacturing a screw member.
Furthermore, the present invention provides a screwing member having a precoat adhesive layer for preventing loosening, having a precoat adhesive layer formed by applying the microcapsule type adhesive composition to the surface of the screwing member and drying it. I will provide a.

  The microcapsule type adhesive of the present invention has excellent storage stability with little deterioration such as capsule swelling and curing of the adhesive component of the composition itself in the liquid composition state before application. Moreover, there is an effect that there is little dripping when applying and processing the adhesive composition on the threaded portion, and suppressing the occurrence of unevenness of the coating film during drying. Further, by using an emulsion having a pH of 6 to 13 as a binder, excellent effects such as stability during coating and prevention of corrosion of the adherend were obtained.

Next, each component constituting the present invention will be described below.
As the epoxy resin constituting the core material of the microcapsule (A) in the present invention, a water-insoluble or hardly soluble epoxy resin having an epoxy group in the molecule is used. This water insolubility or poor solubility can be confirmed by, for example, clouding when the epoxy resin is added to water and stirred. Specific examples of such an epoxy resin include a bisphenol A type epoxy resin obtained by reacting bisphenol A and epichlorohydrin, a bisphenol F type epoxy resin obtained by reacting bisphenol F and epichlorohydrin, and a novolac resin. There are phenol novolac resins obtained by reacting with epichlorohydrin.
Examples of the wall material of the microcapsule (A) in the present invention include melamine resin, urea resin, polyurethane resin, polyurea resin, polyamide resin, epoxy resin, gelatin and the like.

  The microcapsule (A) can be prepared using a known technique such as an interfacial polymerization method, an in-situ method, a spray drying method, or a coacervation method. As a method for producing the microcapsules of the present invention, an in-situ method is particularly preferable in order to obtain the strength and density of the capsule wall membrane. In the in-situ method, the epoxy resin is dispersed in water, the particle size is adjusted, urea, etc., and a prepolymer that can be formalin or a wall film are added to the aqueous dispersion, and the pH is adjusted. After the acidic condition, the capsule wall film is formed by heating and stirring to cause a polymerization reaction.

The binder resin used for the emulsion (B) in the present invention is not particularly limited as long as it is a binder that forms a film after drying and fixes the microcapsule (A) to the screwed portion. Specific examples of the binder resin include acrylic resins, urethane resins, butadiene resins, and vinyl acetate resins that have good adhesion to metals. Examples of specific products of the binder resin include Boncoat DC-118 (acrylic; pH = 8, Dainippon Ink and Chemicals), Luck Star DA-401 (butadiene based; pH = 8, Dainippon Ink and Chemicals). And Bondick 1530 (urethane type; pH = 8, manufactured by Nippon Ink Chemical Co., Ltd.).
The emulsion containing the acrylic resin is obtained by dispersing an acrylic polymer obtained by emulsion polymerization in water. In general, in emulsion polymerization of a resin emulsion, an electrolyte substance is added to an aqueous medium for particle size control. The acrylate monomer used in the emulsion polymerization is easily copolymerized with a wide range of monomers. The acrylic polymer that forms a stable emulsion includes an acrylic ester monomer polymer composed of only the acrylic ester monomer, and the acrylic ester monomer and other monomers such as methacrylate ester, vinyl acetate, styrene, acrylonitrile, It is a copolymer with acrylic acid.

Moreover, the emulsion containing the said vinyl acetate resin can be manufactured by emulsion polymerization which adds a vinyl acetate monomer continuously, heating and stirring an emulsifier or a protective colloid, a polymerization initiator, and a neutralizer aqueous solution. The vinyl acetate monomer can be homopolymerized or copolymerized with many monomers and copolymerized with acrylic acid ester, maleic acid ester, fumaric acid ester, fatty acid vinyl ester, ethylene and the like.
There are various production methods for the urethane resin emulsion. In the phase inversion emulsification method, a polyol component is reacted with an isocyanate to prepare a polymerized polyurethane resin having a hydroxyl group, then diluted with a solvent such as toluene, and an aqueous emulsifier solution is added dropwise to this and stirred. To produce by emulsification. In the blocked isocyanate method, a prepolymer having an isocyanate group at the terminal obtained by reacting an excess equivalent amount of isocyanate with a polyol component is treated with a blocking agent such as ketoximes or phenols to block the terminal isocyanate group, An emulsifier aqueous solution is added dropwise thereto and stirred to produce an emulsion. In the prepolymer method, an emulsifier is used, and a prepolymer having a terminal isocyanate group is mechanically emulsified in water, reacted at a particle interface using a chain extender, and polymerized. In the self-emulsification method, a polar group is introduced into a polymer, the polymer is made into a self-emulsifying type, and it is produced without using an emulsifier.
The pH of the emulsion (B) prepared using the binder resin is preferably 6-13. If the pH is lower than 6, the binder resin may react with the amine of the amine-based curing agent (C) to change the emulsified and dispersed state, resulting in a significant increase in viscosity, which may make it impossible to apply and process the threaded portion. It is not preferable. On the other hand, when the pH exceeds 13, there is a concern about the influence of corrosion or the like on the metal parts, which is not preferable.

  The curing agent used in the present invention can be used without particular limitation as long as the epoxy resin is rapidly cured at room temperature during curing and the curing agent does not volatilize in a coated state. As the curing agent that meets these conditions, a non-volatile, water-soluble or water-dispersible amine-based curing agent (C) is preferable. Examples of the amine curing agent (C) include dimerization reacted with imidazole, 1,3-bis-4-piperidylpropane, 1,6-hexanediamine, methylenedianiline, substituted alkylenediamine, and alkylenediamine. Nonvolatile amines such as liquid polyamides of unsaturated fatty acids (Versamid 125), non-volatile solid amine salts obtained by reacting volatile liquid amines with acids, amine addition compounds, and water-soluble or water-dispersible polyamide resins, etc. is there.

  Hydrolysis neutralized product of alkyl vinyl ether and maleic anhydride copolymer used in the present invention, or hydrolyzed neutralized product of alkyl diene crosslinked product of copolymer of alkyl vinyl ether and maleic anhydride (D), This adhesive is added for the purpose of preventing sagging during application processing to the threaded portion. The alkyl group of the alkyl vinyl ether may be linear or branched, and preferably has 1 to 18 carbon atoms. Examples of the hydrolyzed neutralized product include a copolymer hydrolyzed product of methyl vinyl ether and maleic anhydride, an inorganic base such as sodium hydroxide and potassium hydroxide, an organic base such as aqueous ammonia and triethanolamine. Neutralized with a decadiene cross-linked product of a copolymer of methyl vinyl ether and maleic anhydride neutralized with an inorganic base such as sodium hydroxide or potassium hydroxide, or an organic base such as aqueous ammonia or triethanolamine. is there.

  Various additives can be added to the microcapsule type adhesive of the present invention as required. Examples of the additive include silica, alumina, talc, calcium carbonate, mica, kaolin and other fillers, carbon black, titanium oxide, phthalocyanine compounds and other organic, inorganic pigments, dyes, plasticizers, surfactants, There are antifoaming agents.

  An example of the manufacturing method of this adhesive composition is given. First, an alkyldiene cross-linked product of a copolymer of alkyl vinyl ether and maleic anhydride is dissolved in ion-exchanged water heated to 80 ° C., and after cooling, neutralized with triethanolamine. Next, silica powder as a filler and titanium oxide as a pigment are added and stirred. Subsequently, an amine compound as a curing agent, an emulsion such as an acrylic resin having a pH of 6 to 13, and a pigment are added and stirring is continued. Finally, an epoxy resin microcapsule is added and stirred until the capsule is uniform so that the capsule is not broken, whereby the adhesive composition of the present invention can be produced. In addition, the manufacturing method of this composition can be changed as needed by properties, such as the kind and addition amount of an additive component corresponding to the specific use, or the viscosity of a product.

The blending ratio in the present adhesive composition is 10 to 60 parts, preferably 10 to 50 parts, particularly preferably 30 to 50 parts, and 1 to 40 parts, preferably 1 to 20 parts , of an emulsion in weight ratio. , (Particularly preferably 5 to 20 parts), amine hardener 1 to 50 parts, preferably 1 to 35 parts, and the hydrolysis neutralized product is 0.1 to 10 parts (particularly preferably 5 to 10 parts) ) . The water added to the adhesive composition is preferably 5 to 100 parts, particularly 60 to 80 parts.

Example 1
(1) Preparation of hydrolysis neutralized product of alkyldiene cross-linked product of copolymer of methyl vinyl ether and maleic anhydride:
Add 10 g of alkyldiene cross-linked product of a copolymer of methyl vinyl ether and maleic anhydride (trade name STABILEEZE QM; Tricrystal Co., Ltd.) into 1 L of water, heat to 80 ° C. with stirring, dissolve over 1 hour I let you. Next, after cooling to room temperature, 10 g of triethanolamine was added to obtain a hydrolyzed neutralized product of an alkyldiene crosslinked product of a copolymer of gelled methyl vinyl ether and maleic anhydride.
(2) Preparation of microcapsule component:
1000 g of epoxy resin (Epicoat 828; manufactured by Japan Epoxy Resin Co., Ltd.) was dispersed in 1500 g of water. After adjusting the pH of the suspension to 3 with hydrochloric acid, 200 g of melamine resin prepolymer was added and reacted at 80 ° C. for 3 hours. After cooling, the mixture was neutralized with sodium hydroxide, dehydrated with a centrifugal dehydrator, and dried to obtain microcapsules having an average particle size of 50 μm and an epoxy resin content of 80%.

(Example 2)
Uniformly add 10 g of hydrolyzed neutralized alkyldiene copolymer of methyl vinyl ether and maleic anhydride copolymer prepared in Example 1 and 10 g of silica powder (crystallite AA) to 70 g of ion-exchanged water. Stir for 30 minutes. 30 g of 1-3 dipiperidyl propane and pH = 7.5 butadiene emulsion (trade name Luck Star DA401; manufactured by Dainippon Ink and Chemicals, Inc.) and 80% epoxy resin content prepared in Example 1 were added thereto. 40 g of microcapsules were added and mixed to obtain an adhesive composition.

(Example 3)
Instead of using a pH = 8.0 acrylic emulsion (trade name Boncoat DC-118; manufactured by Dainippon Ink & Chemicals, Inc.) instead of the pH = 7.5 butadiene emulsion used in Example 2, An adhesive composition was obtained by the same procedure as in Example 2.

(Comparative Example 1)
An adhesive composition was obtained by the same procedure as in Example 2, except that the addition of the hydrolysis neutralized product of the alkyldiene crosslinked product of the copolymer of methyl vinyl ether and maleic anhydride was omitted.

(Comparative Example 2)
The same procedure as in Example 2 was used except that an acrylic emulsion (trade name Polytron U-154; manufactured by Asahi Kasei Kogyo Co., Ltd.) having a pH of 4.0 was used instead of the butadiene emulsion having a pH of 7.5. An adhesive composition was obtained.

(Comparative Example 3)
The adhesive composition was prepared by the same procedure as in Example 2 except that a water-soluble polyacetal resin (trade name S-REC KW-10; manufactured by Sekisui Chemical Co., Ltd.) was used instead of the butadiene emulsion having pH = 7.5. Got.

(Comparative Example 4)
An adhesive composition was obtained by adjusting in the same procedure as in Example 2 except that polyvinyl alcohol (GOHSENOL GH-20; manufactured by Nippon Gosei Kagaku) was used instead of the butadiene emulsion having pH = 7.5.

(Comparative Example 5)
An adhesive composition was obtained by the same procedure as in Example 2 except that fumed silica (Aerosil # 200; manufactured by Nippon Aerosil Co., Ltd.) was used instead of the butadiene emulsion having pH = 7.5.

Example 4
The adhesive composition prepared in Examples 1 and 2 was applied to a chromated iron bolt (M = 10 mm; as defined in JIS B 1180), 60 minutes at room temperature, and then 20 minutes at 80 ° C. Bolts were dried and precoated with adhesive. Next, the following test was performed.
Torque test: The tightening torque when the manufactured adhesive pre-coated bolt was tightened to a chromated iron nut (JIS B 1180 standard) was measured. Further, after tightening with a predetermined torque (29.4 N · m) and allowing to stand at 25 ° C. for 48 hours, the average value of n = 5 when the nut was loosened was measured as the breaking torque.
The adhesive compositions were stored at 25 ° C. for 30 days. This adhesive was applied and dried as described above, a bolt precoated with the adhesive was manufactured, and tightening torque and breaking torque were measured (tested after storage as an adhesive composition). Furthermore, the breaking torque and fastening resistance when the bolt pre-coated with this adhesive was promoted for storage at 40 ° C. for 30 days were measured (tested after storage as a pre-coated bolt). The results are shown in Table 1.

(Comparative Example 6)
An adhesive pre-coated bolt was manufactured by the method described in Example 4 using the adhesive composition manufactured in Comparative Examples 1-5. Next, the performance of the adhesive composition and the manufactured bolt were measured by the method described in Example 4. The results are shown in Table 1.

In addition, the symbol in a table | surface means the following.
○: Good ×: Poor-: Not measured * 1 Since there were many capsule drop-offs during tightening, measurements were not made except for the initial test.
* 2 Gelation occurred during storage of the formulation, so no actual measurements were made except for the initial test.
* 3 It was manufactured in Example 1.

  As is clear from Table 1, in Examples 2 and 3, a high breaking torque was exhibited and stabilized immediately after production, after being stored as an adhesive composition, and after being stored as a pre-coated bolt. Breaking torque and tightening resistance are shown. Therefore, it is clear that the microcapsule type adhesive composition of the present invention is superior in stability as an adhesive composition and stability in tightening resistance as compared with the comparative adhesive composition.

  The microcapsule adhesive composition of the present invention can be applied to a member having a threaded portion such as a bolt, a screw, or a nut to form a precoat adhesive layer for preventing loosening. However, the microcapsule-type adhesive composition of the present invention can be used as long as it can be pressurized to such an extent that microcapsules can be broken between adherends, and there is no limitation on its use. Accordingly, the planar members can be bonded together by applying pressure to the adhesive composition of the present invention to such an extent that the microcapsules can be broken.

Claims (12)

Microcapsules (A) 10 to 50 containing an epoxy resin as a core material and one or more resins selected from an aldehyde resin, a melamine resin, a urea resin, a polyurethane resin, a polyurea resin, a polyamide resin, or an epoxy resin as a wall material comprising a binder resin having emulsifying ability, emulsion is pH6~13 (B) 1~20 parts by weight; parts by weight of a water-soluble or water-dispersible amine-based curing agent (C) 1 to 50 parts by weight; and alkyl A microcapsule type adhesive composition comprising 0.1 to 10 parts by weight of a hydrolyzed neutralized product (D) of a crosslinked alkyldiene copolymer of vinyl ether and maleic anhydride . The microcapsule type adhesive composition according to claim 1, further comprising 5 to 100 parts by weight of water (E).   The microcapsule type adhesive composition according to claim 1, wherein the epoxy resin used as a core material of the microcapsule (A) is a water-insoluble or poorly water-soluble epoxy resin.   The microcapsule type adhesive composition according to claim 1, wherein the binder resin contained in the emulsion (B) is an acrylic resin, a urethane resin, a butadiene resin, or a mixture thereof that can form a film after drying. .   The microcapsule type adhesive composition according to claim 1, wherein the amine-based curing agent (C) is non-volatile or hardly volatile. The epoxy resin as a core material, aldehyde resins, melamine resins as the wall material, urea resins, polyurethane resins, polyurea resins, polyamide resins, or microcapsules (A) 10 to 50 parts by weight of an epoxy resin; binder having emulsifying ability 1 to 20 parts by weight of an emulsion (B) containing a resin and having a pH of 6 to 13; 1 to 50 parts by weight of a water-soluble or water-dispersible amine-based curing agent (C); and a copolymer of alkyl vinyl ether and maleic anhydride A microcapsule type adhesive composition containing 0.1 to 10 parts by weight of a hydrolyzed neutralized product (D) of a polymer alkyldiene crosslinked product is applied to the surface of a screw member; and precoated by drying. A method for producing a screw member having a pre-coating adhesive layer for preventing loosening, wherein an adhesive layer is formed.   The manufacturing method of the screwing member which has the precoat adhesive layer for loosening prevention of Claim 6 whose epoxy resin used as a core material of the said microcapsule (A) is a water-insoluble or slightly water-soluble epoxy resin. .   The precoat adhesive layer for loosening prevention according to claim 6, wherein the binder resin contained in the emulsion (B) is an acrylic resin, a urethane resin, a butadiene resin, or a mixture thereof capable of forming a film after drying. The manufacturing method of the screwing member which has this.   The manufacturing method of the screwing member which has the precoat adhesive bond layer for loosening prevention of Claim 6 whose said amine type hardening | curing agent (C) is non-volatile or hardly volatile.   The manufacturing method of the screwing member which has a precoat adhesive layer for locking prevention according to claim 6, wherein the screwing member is a member having a screwing surface selected from the group consisting of a bolt, a screw and a nut. 10-50 parts by weight of microcapsules (A) containing epoxy resin as the core material and aldehyde resin, melamine resin, urea resin, polyurethane resin, polyurea resin, polyamide resin, or epoxy resin as the wall material; 1 to 20 parts by weight of an emulsion (B) containing a resin and having a pH of 6 to 13; 1 to 50 parts by weight of a water-soluble or water-dispersible amine-based curing agent (C); and a copolymer of alkyl vinyl ether and maleic anhydride precoated by and dried; containing hydrolyzate neutralized product (D) 0.1 to 10 parts by weight of alkyl diene crosslinked product of a polymer, a microcapsule type adhesive composition was applied to the surface of the threaded member A screw member having a pre-coating adhesive layer for preventing loosening, in which an adhesive layer is formed.   The screw member having a precoat adhesive layer for locking according to claim 11, wherein the screw member is a member having a screw surface selected from the group consisting of a bolt, a screw, and a nut.