JPWO2019124255A1 - Manufacturing method of liquid crystal display protective plate - Google Patents

Abstract

The present invention provides a method for manufacturing a liquid crystal display protective plate having a functional layer, in which the in-plane retardation value is within a suitable range and the visibility of the liquid crystal display through a polarizing filter is good. The method for manufacturing the liquid crystal display protective plate (1) of the present invention includes a step (X) of preparing a resin plate (16X) and a step (Y) of attaching a functionality-imparting film (17) to the resin plate (16X). ) And. The step (Y) is carried out under the condition that the temperature of the resin plate (16X) does not exceed 60 ° C. The in-plane retardation value (R1) of the resin plate (16X) is 50 to 210 nm, the in-plane retardation value (R2) of the liquid crystal display protective plate (1) is 50 to 210 nm, and the resin plate (16X). The ratio (R2 / R1) of the in-plane retardation value (R2) of the liquid crystal display protective plate (1) to the in-plane retardation value (R1) is 0.9 to 1.1.

Description

The present invention relates to a method for manufacturing a liquid crystal display protective plate.

A liquid crystal display and a touch panel display in which a liquid crystal display and a touch panel are combined may be provided with a protective plate on the front side thereof in order to prevent scratches on the surface. In the present specification, this protective plate is referred to as a "liquid crystal display protective plate".
As a liquid crystal display protective plate, a cured film having scratch resistance (hard coat property) and / or low reflectivity for improving visibility and glare are suppressed on the surface of a resin plate composed of at least one thermoplastic resin layer. A laminated body in which various functional layers such as an antiglare film, an antifouling film that suppresses the adhesion of dirt, an antistatic film that suppresses the adhesion of dust, and a transparent conductive film that imparts the necessary conductivity to the touch panel are formed. It is being considered for use.
For example, Patent Document 1 discloses a scratch-resistant resin plate that includes a methacrylic resin plate and a cured film formed on at least one surface thereof and is suitable as a display window protective plate for a portable information terminal. (Claims 1, 2, 7, etc.). Patent Document 2 describes a polycarbonate resin laminate for a liquid crystal display cover, which includes a laminate in which a methacrylic resin layer is laminated on one surface of a polycarbonate resin layer, and a cured film formed on the methacrylic resin layer of the laminate. It is disclosed (claim 1).

Examples of the method for manufacturing the resin plate include an injection molding method and an extrusion molding method.
As a method for forming the functional layer, a method of applying a liquid curable composition containing a thermosetting compound or an active energy ray-curable compound and curing the coating film by heating or irradiation with active energy rays (Patent Document 1, Patent Document 1, 2); A method in which a functional material or a precursor of a functional material is dispersed or dissolved in water, an organic solvent, or the like, and dried or heated; a PET (polyethylene terephthalate) film having a functional layer formed in advance on the surface. Examples thereof include a method of laminating resin films such as the above with an adhesive or an adhesive.
A drying step or heating step for adjusting the warpage state, etc., and a thermoforming step of performing shape processing such as curved surface processing on the resin plate before forming the functional layer or the resin plate after forming the functional layer. Etc. may be implemented.

The liquid crystal display protective plate is installed on the front side (viewer side) of the liquid crystal display, and the viewer sees the screen of the liquid crystal display through the protective plate. Here, since the liquid crystal display protective plate hardly changes the polarization property of the light emitted from the liquid crystal display, when the screen is viewed through a polarizing filter such as polarized sunglasses, the angle formed by the polarization axis of the emitted light and the transmission axis of the polarizing filter In some cases, the screen becomes dark and the visibility of the image is reduced. Therefore, a liquid crystal display protective plate capable of suppressing a decrease in visibility of an image when viewing the screen of a liquid crystal display through a polarizing filter has been studied. For example, Patent Document 3 describes a scratch-resistant resin plate having a cured film formed on at least one surface of a resin substrate, and has an in-plane retardation value (hereinafter, also referred to as “Re value”) of 85 to 5. A liquid crystal display protective plate having a thickness of 300 nm is disclosed (claim 1).

Japanese Unexamined Patent Publication No. 2004-299199 Japanese Unexamined Patent Publication No. 2006-103169 Japanese Unexamined Patent Publication No. 2010-0857978

The resin plate used for the liquid crystal display protective plate may be out of the desired range due to a decrease in the Re value due to heat applied after the resin plate is manufactured, such as in the process of forming a functional layer. In this case, in particular, the visibility of the image when the liquid crystal display is visually recognized through a polarizing filter such as polarized sunglasses may be significantly reduced.

The present invention has been made in view of the above circumstances, and provides a functional layer in which the in-plane retardation value (Re value) is within a suitable range and the visibility of the liquid crystal display through the polarizing filter is good. An object of the present invention is to provide a method for manufacturing a liquid crystal display protective plate.

The present invention provides the following methods for manufacturing a liquid crystal display protective plate [1] to [5].
[1] A method for manufacturing a liquid crystal display protective plate, comprising a step (X) of preparing a resin plate and a step (Y) of attaching a functionalizing film to the resin plate.
The step (Y) is carried out under the condition that the temperature of the resin plate does not exceed 60 ° C.
The in-plane retardation value (R1) of the resin plate is 50 to 210 nm.
The in-plane retardation value (R2) of the liquid crystal display protective plate is 50 to 210 nm.
The liquid crystal display protection in which the ratio (R2 / R1) of the in-plane retardation value (R2) of the liquid crystal display protection plate to the in-plane retardation value (R1) of the resin plate is 0.9 to 1.1. How to make a board.

[2] The method for manufacturing a liquid crystal display protective plate according to [1], wherein the resin plate is a thermoplastic resin laminate in which a methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer.

[3] Step (X) is
A step of co-extruding the thermoplastic resin laminate in which the methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer from a T-die in a molten state.
The molten thermoplastic resin laminate is sandwiched between the first cooling roll and the second cooling roll while forming a bank, and the thermoplastic resin laminate is wound around the second cooling roll, and then a third. The process of cooling by wrapping it around a cooling roll,
The method for manufacturing a liquid crystal display protective plate according to [2], which includes a step of picking up the thermoplastic resin laminate after cooling with a pick-up roll.

[4] The functionalizing film is obtained by laminating a base film and at least one functional layer on the surface of the base film.
The method for manufacturing a liquid crystal display protective plate according to any one of [1] to [3], wherein the in-plane retardation value (R3) of the base film is 10 nm or less.
[5] The method for manufacturing a liquid crystal display protective plate according to [4], wherein the base film is made of an acrylic resin or a triacetyl cellulose-based resin.

According to the present invention, a method for manufacturing a liquid crystal display protective plate having a functional layer, in which the in-plane retardation value (Re value) is within a suitable range and the visibility of the liquid crystal display through a polarizing filter is good. Can be provided.

It is a schematic sectional view of the liquid crystal display protection plate of 1st Embodiment which concerns on this invention. It is a schematic cross-sectional view of the liquid crystal display protection plate of the 2nd Embodiment which concerns on this invention. It is a schematic diagram of the manufacturing apparatus of the extruded resin plate of one Embodiment which concerns on this invention.

"Liquid crystal display protection plate"
The present invention relates to a method for manufacturing a liquid crystal display protective plate having a resin plate and a functionalizing film attached to at least one surface of the resin plate. The liquid crystal display protective plate can be suitably used for a liquid crystal display and a touch panel display in which a liquid crystal display and a touch panel are combined.
The resin plate is preferably a thermoplastic resin laminate in which a methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer. The polycarbonate resin-containing layer is a layer containing a polycarbonate resin (PC), and the methacrylic resin-containing layer is a layer containing a methacrylic resin (PM). Polycarbonate resin (PC) is excellent in impact resistance, and methacrylic resin (PM) is excellent in gloss, transparency, and surface hardness. Therefore, the liquid crystal display protective plate of the present invention including the resin plate in which these resins are laminated is excellent in gloss, transparency, impact resistance, and surface hardness.

(Resin plate)
<Methyl resin-containing layer>
The methacrylic resin-containing layer contains one or more methacrylic resins (PM). A methacrylic resin (PM) is a homopolymer or copolymer containing a structural unit derived from one or more methacrylic acid esters. From the viewpoint of transparency, the content of the methacrylic acid ester monomer unit in the methacrylic acid resin (PM) is preferably 50% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more. It may be 100% by mass.

Preferred methacrylic acid esters include, for example, methyl methacrylate (MMA), ethyl methacrylate, butyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate; monocyclic aliphatic methacrylate. Hydrocarbon ester; Examples thereof include methacrylic acid polycyclic aliphatic hydrocarbon ester. From the viewpoint of transparency, the methacrylic resin (PM) preferably contains MMA units, and the content of MMA units in the methacrylic resin (PM) is preferably 50% by mass or more, more preferably 80% by mass or more, particularly. It is preferably 90% by mass or more, and may be 100% by mass.

The methacrylic resin (PM) may contain structural units derived from one or more other monomers other than the methacrylic acid ester. Other monomers include methyl acrylate (MA), ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate and the like. Acrylic acid esters; styrenes; acrylonitrile, methacrylonitrile; maleic anhydride, phenylmaleimide, cyclohexylmaleimide; and the like. Of these, MA is preferable from the viewpoint of transparency. For example, a copolymer of MMA and MA has excellent transparency and is preferable. The content of MMA in this copolymer is preferably 80% by mass or more, more preferably 85% by mass or more, particularly preferably 90% by mass or more, and may be 100% by mass.

The methacrylic resin (PM) is preferably obtained by polymerizing one or more methacrylic acid esters containing MMA and, if necessary, other monomers. When a plurality of types of monomers are used, usually, a plurality of types of monomers are mixed to prepare a monomer mixture, and then polymerization is performed. The polymerization method is not particularly limited, and from the viewpoint of productivity, radical polymerization methods such as a massive polymerization method, a suspension polymerization method, a solution polymerization method, and an emulsion polymerization method are preferable.

The weight average molecular weight (Mw) of the methacrylic resin (PM) is preferably 40,000 to 500,000. When the Mw is 40,000 or more, the methacrylic resin-containing layer is excellent in scratch resistance and heat resistance, and when the Mw is 500,000 or less, the methacrylic resin-containing layer is excellent in moldability.
In the present specification, unless otherwise specified, "Mw" is a standard polystyrene-equivalent value measured using gel permeation chromatography (GPC).

The methacrylic resin-containing layer can contain methacrylic resin (PM) and, if necessary, one or more other polymers.
For example, the methacrylic resin-containing layer can be made of a methacrylic resin composition (MR) containing a methacrylic resin (PM) and an SMA resin (S) (hereinafter, also simply referred to as a resin composition (MR)).
As used herein, the term "SMA resin" includes structural units derived from one or more aromatic vinyl compounds and structural units derived from one or more acid anhydrides containing maleic anhydride (MAH). More preferably, it is a copolymer containing a structural unit derived from a methacrylic acid ester.
The methacrylic resin composition (MR) can preferably contain 5 to 80% by mass of the methacrylic resin (PM) and 95 to 20% by mass of the SMA resin (S).

The SMA resin (S) is a copolymer containing a structural unit derived from one or more aromatic vinyl compounds and one or more acid anhydrides containing MAH.
Aromatic vinyl compounds include styrene (St); nuclear alkyl-substituted styrenes such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, and 4-tert-butylstyrene; α-methylstyrene. And α-alkyl substituted styrenes such as 4-methyl-α-methylstyrene; Of these, styrene (St) is preferable from the viewpoint of availability. From the viewpoint of transparency and moisture resistance of the resin composition (MR), the content of the aromatic vinyl compound monomer unit in the SMA resin (S) is preferably 50 to 85% by mass, more preferably 55 to 82. It is by mass, particularly preferably 60 to 80% by mass.
As the acid anhydride, at least maleic anhydride (MAH) can be used from the viewpoint of availability, and if necessary, other acid anhydrides such as citraconic anhydride and dimethyl maleic anhydride can be used. From the viewpoint of transparency and heat resistance of the resin composition (MR), the content of the acid anhydride monomer unit in the SMA resin (S) is preferably 15 to 50% by mass, more preferably 18 to 45% by mass. %, Especially preferably 20 to 40% by mass.

The SMA resin (S) can contain structural units derived from one or more kinds of methacrylic ester monomers in addition to aromatic vinyl compounds and acid anhydrides. Examples of the methacrylic acid ester unit include structural units capable of forming a methacrylic resin (PM), and MMA is preferable from the viewpoint of heat resistance and transparency of the SMA resin (S). From the viewpoint of the transparency of the resin plate, the content of the methacrylate ester monomer unit in the SMA resin (S) is preferably 1 to 35% by mass, more preferably 3 to 30% by mass, and particularly preferably 5 to 5% by mass. It is 26% by mass. In this case, the content of the aromatic vinyl compound monomer unit is preferably 50 to 84% by mass, and the content of the acid anhydride monomer unit is preferably 15 to 49% by mass.

The SMA resin (S) may have a structural unit derived from an aromatic vinyl compound, an acid anhydride, and a monomer other than the methacrylate ester. As the other monomer, those described above can be used in the description of the methacrylic resin (PM). The content of the other monomer unit in the SMA resin (S) is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

The SMA resin (S) is obtained by polymerizing an aromatic vinyl compound, an acid anhydride, a methacrylic acid ester if necessary, and another monomer if necessary. In this polymerization, usually, a plurality of kinds of monomers are mixed to prepare a monomer mixture, and then the polymerization is carried out. The polymerization method is not particularly limited, and a radical polymerization method such as a massive polymerization method and a solution polymerization method is preferable from the viewpoint of productivity.

The Mw of the SMA resin (S) is preferably 40,000 to 300,000. When the Mw is 40,000 or more, the methacrylic resin-containing layer is excellent in scratch resistance and impact resistance, and when the Mw is 300,000 or less, the methacrylic resin-containing layer is excellent in moldability.

The resin composition (MR) is obtained, for example, by mixing a methacrylic resin (PM) and a SMA resin (S). Examples of the mixing method include a melt mixing method and a solution mixing method. In the melt mixing method, a single-screw or multi-screw kneader; an open roll, a Banbury mixer, a melt kneader such as a kneader, or the like is used, and if necessary, an inert gas such as nitrogen gas, argon gas, or helium gas is used. Melt kneading can be performed in an atmosphere. In the solution mixing method, the methacrylic resin (A) and the SMA resin (S) can be dissolved in an organic solvent such as toluene, tetrahydrofuran, and methyl ethyl ketone and mixed.

The methacrylic resin-containing layer is composed of a methacrylic resin composition (MR), and the methacrylic resin composition (MR) contains methacrylic resin (PM), SMA resin (S), and, if necessary, one or more other polymers. Can include.
The other polymer is not particularly limited, and other thermoplastic resins such as polyolefins such as polyethylene and polypropylene, polyamide, polyphenylene sulfide, polyetheretherketone, polyester, polysulfone, polyphenylene oxide, polyimide, polyetherimide, and polyacetal. ; Examples include thermosetting resins such as phenol resin, melamine resin, silicone resin, and epoxy resin. The content of the other polymer in the methacrylic resin-containing layer is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less.

The methacrylic resin-containing layer can contain various additives, if necessary. Additives include antioxidants, heat deterioration inhibitors, UV absorbers, light stabilizers, lubricants, mold release agents, polymer processing aids, antistatic agents, flame retardants, dyes / pigments, organic pigments, and light diffusion. Examples thereof include agents, matting agents, impact resistance modifiers such as core-shell particles and block copolymers, and phosphors. The content of the additive can be appropriately set as long as the effect of the present invention is not impaired. For example, the content of the antioxidant is 0.01 to 1 part by mass, the content of the ultraviolet absorber is 0.01 to 3 parts by mass, and the light stabilizer is 100 parts by mass with respect to 100 parts by mass of the resin constituting the methacrylic resin-containing layer. The content of the above is preferably 0.01 to 3 parts by mass, the content of the lubricant is preferably 0.01 to 3 parts by mass, and the content of the dye / pigment is preferably 0.01 to 3 parts by mass.

When the methacrylic resin (PM) contains another polymer and / or an additive, the timing of addition may be during or after the polymerization of the methacrylic resin (PM).
When the methacrylic resin composition (MR) contains other polymers and / or additives, the timing of addition may be at the time of polymerization of the methacrylic resin (PM) and / or the SMA resin (S), or a mixture of these resins. It may be time or after mixing.

From the viewpoint of the stability of the heat-melting molding, melt volume flow rate of the constituent resin of a methacrylic resin containing layer (MVR) is preferably 0.5~20cm ^3/10 min. In the present specification, the MVR of the constituent resin of the methacrylic resin-containing layer is a value measured under the conditions of 230 ° C. and a load of 37.3 N in accordance with IS0-1133.

<Polycarbonate resin-containing layer>
The polycarbonate resin-containing layer contains one or more types of polycarbonate resin (PC). The polycarbonate resin (PC) is preferably obtained by copolymerizing one or more divalent phenols and one or more carbonate precursors. The production method includes an interfacial polymerization method in which an aqueous solution of dihydric phenol and an organic solvent solution of a carbonate precursor are reacted at an interface, and a reaction between the dihydric phenol and the carbonate precursor under high temperature, reduced pressure, and solvent-free conditions. The ester exchange method and the like can be mentioned.

Examples of the divalent phenol include 2,2-bis (4-hydroxyphenyl) propane (commonly known as bisphenol A), 1,1-bis (4-hydroxyphenyl) ethane, and 1,1-bis (4-hydroxyphenyl) cyclohexane. 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) sulfide, and bis (4-hydroxyphenyl) Hydroxyphenyl) sulfone and the like, with bisphenol A being preferred. Examples of the carbonate precursor include carbonyl halides such as phosgene; carbonate esters such as diphenyl carbonate; and haloformates such as dihaloformates of divalent phenols.

The Mw of the polycarbonate resin (PC) is preferably 10,000 to 100,000, more preferably 20,000 to 70,000. When Mw is 10,000 or more, the polycarbonate resin-containing layer is excellent in impact resistance and heat resistance, and when Mw is 100,000 or less, the polycarbonate resin-containing layer is excellent in moldability.

A commercially available product may be used as the polycarbonate resin (PC). Sumika Stylon Polycarbonate Co., Ltd. "Calibre (registered trademark)" and "SD Polyca (registered trademark)", Mitsubishi Engineering Plastics Co., Ltd. "Upiron / Novarex (registered trademark)", Idemitsu Kosan Co., Ltd. "Taflon (registered trademark)" "Trademark)" and "Panlite (registered trademark)" manufactured by Teijin Chemicals Ltd. can be mentioned.

The polycarbonate resin-containing layer can contain one or more other polymers and / or various additives, if necessary. As the other polymer and various additives, the same ones as described above can be used in the description of the methacrylic resin-containing layer. The content of the other polymer in the polycarbonate resin-containing layer is preferably 15% by mass or less, more preferably 10% by mass or less, and particularly preferably 5% by mass or less. The content of the additive can be appropriately set as long as the effect of the present invention is not impaired. The content of the antioxidant is 0.01 to 1 part by mass, the content of the ultraviolet absorber is 0.01 to 3 parts by mass, and the content of the light stabilizer is 0 with respect to 100 parts by mass of the polycarbonate resin (PC). It is preferable that the content is 0 to 1 to 3 parts by mass, the content of the lubricant is 0.01 to 3 parts by mass, and the content of the dye / pigment is 0.01 to 3 parts by mass.
When the other polymer and / or the additive is added to the polycarbonate resin (PC), the timing of addition may be during or after the polymerization of the polycarbonate resin (PC).

From the viewpoint of the stability of the heat-melting molding, melt volume flow rate of the constituent resin of the polycarbonate resin-containing layer (MVR) is preferably 1 to 20 cm ^3/10 min. In the present specification, the MVR of the constituent resin of the polycarbonate resin-containing layer is a value measured under the conditions of 300 ° C. and a load of 11.8 N in accordance with IS0-1133.

<Thickness of resin plate and each layer>
The total thickness of the resin plate used for the liquid crystal display protective plate of the present invention is preferably 0.4 to 2 mm, more preferably 0.5 to 1.5 mm. If it is too thin, the rigidity may be insufficient, and if it is too thick, it may hinder the weight reduction of the liquid crystal display or the touch panel display including the liquid crystal display.
The thickness of the methacrylic resin-containing layer is not particularly limited, and is preferably 20 to 200 μm, more preferably 25 to 150 μm, and particularly preferably 30 to 100 μm, because the balance between scratch resistance and impact resistance is excellent. The thickness of the polycarbonate resin-containing layer is preferably 0.3 to 4.9 mm, more preferably 0.6 to 2.9 mm.

<Laminate structure>
The resin plate included in the liquid crystal display protective plate of the present invention may have another resin layer as long as the methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer. The laminated structure of the resin plate includes a two-layer structure of a polycarbonate resin-containing layer and a methacrylic resin-containing layer; a three-layer structure of a methacrylic resin-containing layer, a polycarbonate resin-containing layer, and a methacrylic resin-containing layer; -A three-layer structure of another resin layer; another resin layer-a methacrylic resin-containing layer-a three-layer structure of a polycarbonate resin-containing layer; and the like.
Since both sides of the resin plate have excellent scratch resistance and the occurrence of warpage of the resin plate due to changes in humidity or the like is suppressed, the resin plate has a laminated structure in which methacrylic resin-containing layers are laminated on both sides of the polycarbonate resin-containing layer. Is preferable.

<In-plane retardation value (R1) of the resin plate>
Details will be described later, but in order to improve the visibility of the liquid crystal display through a polarizing filter such as polarized sunglasses, in the present invention, the in-plane retardation value (R2) of the finally manufactured liquid crystal display protective plate. ) Is 50 to 210 nm. Therefore, in the present invention, the in-plane retardation value (R1) of the resin plate used for manufacturing the liquid crystal display protective plate is set to 50 to 210 nm.

(Functionalizing film)
The functionalizing film attached to the surface of the resin plate may be any one capable of imparting various functions, and is preferably a base film and at least one functional layer laminated on the surface of the base film. ..
The in-plane retardation value (R3) of the base film of the functionalizing film is preferably 10 nm or less. If the in-plane retardation value (R3) of the base film is 10 nm or less and sufficiently smaller than the in-plane retardation value (R1) of the resin plate, the final retardation of the liquid crystal display protective plate is obtained. It is easy to control the value (R2) within the above range.

As the material of the base film, a known material can be used, and examples thereof include polyethylene terephthalate (PET), triacetyl cellulose (TAC) resin, polycarbonate resin, acrylic resin, and polyolefin. Above all, since the in-plane retardation value (R3) of the base film can be made smaller and the final retardation value (R2) of the liquid crystal display protective plate can be easily controlled within the above range, TAC and acrylic resins Etc. are preferable. Acrylic resins are particularly preferable from the viewpoint that warpage due to water absorption is unlikely to occur.

The functional layers include a hardened film having scratch resistance (hard coat property) and / or low reflectivity for improving visibility, an antiglare film that suppresses glare, an antifouling film that suppresses dirt adhesion, and dust. Examples thereof include an antistatic film that suppresses adhesion, a transparent conductive film that imparts conductivity necessary for a touch panel, and the like. A plurality of functional layers may be imparted to the resin plate.

The thickness of the functional layer can be appropriately designed according to the desired function and the like.
For example, the thickness of the scratch-resistant (hard coatable) cured film (scratch-resistant layer) is preferably 2 to 30 μm, more preferably 3 to 10 μm. If it is too thin, the surface hardness will be insufficient, and if it is too thick, cracks may occur due to bending during the manufacturing process.
For example, the thickness of the low-reflection cured coating (low-reflection layer) is preferably 80 to 200 nm, more preferably 100 to 150 nm. If it is too thin or too thick, the low reflection performance may be insufficient.

The method of forming the functional layer on the surface of the base film is not particularly limited.
For example, the surface of the base film is cured by applying a curable composition containing a thermosetting compound or an active energy ray-curable compound, preferably in a liquid state, and curing the coating film by heating or irradiation with active energy rays. A film can be formed. The active energy ray-curable compound is a compound having a property of being cured by being irradiated with an active energy ray such as an electron beam and ultraviolet rays. Examples of the thermosetting composition include a polyorganosiloxane type and a crosslinked acrylic type. Examples of the active energy ray-curable composition include a curable compound such as a monofunctional or polyfunctional acrylate-based monomer or oligomer and a photopolymerization initiator. The cured film can be formed by using a commercially available hard coating agent. As another method for forming a functional layer on the surface of a base film, a functional material or a precursor of the functional material is used in water, an organic solvent, or the like. Examples thereof include a method of applying a dispersed or dissolved liquid and drying or heating.

(Implementation of Liquid Crystal Display Protective Plate)
1 and 2 are schematic cross-sectional views of the liquid crystal display protective plate of the first and second embodiments according to the present invention. In the figure, reference numerals 1 and 2 are liquid crystal display protective plates, reference numerals 16X and 16Y are resin plates, reference numeral 17 is a functionalizing film, reference numeral 21 is a polycarbonate resin-containing layer, and reference numerals 22, 22A and 22B are methacrylic resin-containing layers and reference numerals. Reference numeral 24 indicates a base film, and reference numeral 24 indicates a functional layer. The liquid crystal display protective plate 1 of the first embodiment is formed by laminating a functionalizing film 17 on one surface of a resin plate 16X having a two-layer structure of a polycarbonate resin-containing layer 21-methacrylic resin-containing layer 22. The liquid crystal display protective plate 2 of the second embodiment functions on one surface of the resin plate 16Y having a three-layer structure of the first methacrylic resin-containing layer 22A-polycarbonate resin-containing layer 21-2nd methacrylic resin-containing layer 22B. The sex-imparting film 17 is bonded together. The functionality-imparting film 17 is formed by laminating at least one functional layer 24 on the surface of the base film 23. In the liquid crystal display protective plates 1 and 2, the resin plate 16X or 16Y and the base film 23 of the functionality-imparting film 17 are bonded together.
The design of the resin plate, the functionalizing film, and the liquid crystal display protective plate can be changed as appropriate. For example, in FIG. 1, the functionality-imparting film 17 is bonded to the methacrylic resin-containing layer 22 side of the resin plate 16X, but the functionality-imparting film 17 is bonded to the polycarbonate resin-containing layer 21 side of the resin plate 16X. May be good.

(In-plane retardation value (R2) of the liquid crystal display protective plate)
Since the visibility of the liquid crystal display through a polarizing filter such as polarized sunglasses is improved, the in-plane retardation value (R2) of the liquid crystal display protective plate is set to 50 to 210 nm. Whether it is smaller or larger than this range, the visibility of the liquid crystal display through the polarizing filter may be poor. Specifically, when R2 exceeds 210 nm, when the liquid crystal display is visually recognized through a polarizing filter, the difference in transmittance of each wavelength in the visible light range becomes large, and various colors appear to be mixed, and the image is visually recognized. It becomes difficult. When R2 is less than 50 nm, the transmittance of all wavelengths in the visible light range is greatly reduced, resulting in an overall black image, which makes it difficult to visually recognize. In the range of R2 of 50 to 210 nm, the larger the value, the brighter the image tends to be, and the smaller the value, the smaller the number of colors that are mixed and visually recognized tends to be reduced. In particular, when the liquid crystal display is visually recognized through the polarizing filter, the balance between brightness and color is good and the visibility is excellent. Therefore, R2 is preferably 60 to 200 nm, more preferably 80 to 180 nm, and particularly preferably 100 to 150 nm. is there.

[Manufacturing method of liquid crystal display protective plate]
The method for manufacturing a liquid crystal display protective plate of the present invention includes a step (X) of preparing a resin plate and a step (Y) of attaching a functionalizing film to the resin plate.

(Step (X))
The resin plate can be produced by a known method such as a cast molding method, an injection molding method, or an extrusion molding method, and the extrusion molding method is preferable in terms of excellent production efficiency, and the coextrusion molding method is particularly preferable.
The constituent resins of the polycarbonate resin-containing layer and the methacrylic resin-containing layer are each heated and melted, and a wide discharge port is provided in the state of a thermoplastic resin laminate in which the methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer. It is co-extruded from the T-die having it in a molten state.
Examples of the laminating method include a feed block method of laminating before the inflow of the T-die, a multi-manifold method of laminating inside the T-die, and the like. The multi-manifold method is preferable from the viewpoint of improving the interfacial smoothness between the layers of the resin plate and from the viewpoint of excellent thickness accuracy of each layer.

The molten thermoplastic resin laminate co-extruded from the T-die is cooled using a plurality of cooling rolls. In the present invention, three or more cooling rolls adjacent to each other are used, and a molten thermoplastic resin laminate is placed between the nth (where n ≧ 1) cooling roll and the n + 1th cooling roll. Cooling is performed by repeating the operation of sandwiching and winding around the n + 1th cooling roll a plurality of times from n = 1. For example, when three cooling rolls are used, the number of repetitions is two.

Examples of the cooling roll include a metal roll and an elastic roll having a metal thin film on the outer peripheral portion (hereinafter, also referred to as a metal elastic roll). Examples of the metal roll include a drilled roll and a spiral roll. The surface of the metal roll may be a mirror surface, or may have a pattern, unevenness, or the like. The metal elastic roll is composed of, for example, a shaft roll made of stainless steel or the like, a metal thin film made of stainless steel or the like covering the outer peripheral surface of the shaft roll, and a fluid sealed between the shaft roll and the metal thin film. , Elasticity can be exhibited by the presence of fluid. The thickness of the metal thin film is preferably about 2 to 5 mm. The metal thin film preferably has flexibility, flexibility, and the like, and preferably has a seamless structure without weld joints. A metal elastic roll provided with such a metal thin film has excellent durability, and if the metal thin film is mirror-finished, it can be handled in the same manner as a normal mirror-finished roll, and a pattern, unevenness, etc. can be imparted to the metal thin film. It is easy to use because it becomes a roll that can transfer the shape of the film.

The resin plate obtained after cooling is picked up by a pick-up roll. The above coextrusion, cooling, and take-back steps are carried out continuously.

FIG. 3 shows a schematic view of a manufacturing apparatus including a T-die 11, first to third cooling rolls 12 to 14, and a pair of take-back rolls 15 as an embodiment. The thermoplastic resin laminate co-extruded from the T-die 11 is cooled by using the first to third cooling rolls 12 to 14, and is taken up by a pair of take-up rolls 15. In the illustrated example, the third cooling roll 14 is a "cooling roll on which the thermoplastic resin laminate is finally wound (hereinafter, also simply referred to as a final cooling roll)".
The fourth and subsequent cooling rolls may be installed adjacent to the subsequent stage of the third cooling roll 14. In this case, the cooling roll on which the thermoplastic resin laminate is wound last is the "last cooling roll". A transport roll can be installed between the plurality of cooling rolls adjacent to each other and the take-up roll as needed, but the transport roll is not included in the "cooling roll".
The configuration of the manufacturing apparatus can be appropriately redesigned as long as it does not deviate from the gist of the present invention.

Since the in-plane retardation value (R2) of the finally manufactured liquid crystal display protective plate is 50 to 210 nm, in the present invention, the in-plane retardation value (R1) of the resin plate is 50 to 210 nm. As described above, the resin plate is manufactured.
"Letteration" is the phase difference between light in the direction of the molecular backbone and light in the direction perpendicular to it. Generally, a polymer can be obtained by heating and melt molding to obtain an arbitrary shape, but it is known that the molecules are oriented by the stress generated in the process of heating and cooling to generate retardation. Therefore, in order to control the retardation, it is necessary to control the orientation of the molecule. The orientation of the molecules is generated, for example, by the stress during molding near the glass transition temperature of the polymer. In addition, in this specification, "letteration" means in-plane lettering unless otherwise specified.
The orientation of the molecules can be controlled by optimizing the production conditions in the process of extrusion molding, whereby the in-plane retardation value (R1) of the resin plate after extrusion molding can be optimized.

In the present specification, unless otherwise specified, the "peripheral speed ratio" is the ratio of the peripheral speed of any other cooling roll or take-up roll to the second cooling roll. The peripheral speed of the second cooling roll is expressed as V2, the peripheral speed of the third cooling roll is expressed as V3, and the peripheral speed of the take-up roll is expressed as V4.
For example, the amount of banks, the overall temperature (TT) of the thermoplastic resin laminate at the position where it is peeled off from the last cooling roll, the peripheral speed of the take-up roll (V4), and the peripheral speed of the second cooling roll (V2). By adjusting the peripheral speed ratio (V4 / V2) or the like, the in-plane retardation value (R1) of the resin plate can be controlled within a desired range.

In the present specification, the "bank" is a resin pool formed in the gap between the first cooling roll and the second cooling roll. The larger the bank amount, the larger the in-plane retardation value (Re value) tends to increase. The reason is that when the molten resin flows from the position where the resin pool is generated to the minimum gap between the first cooling roll and the second cooling roll, the molecules are oriented due to the difference in the flow velocity inside the resin as the resin cools. I think that the. By relatively increasing the amount of resin supplied to the cooling roll or relatively decreasing the rotation speed of the cooling roll, it is possible to adjust the bank relatively large.

The overall temperature (TT) of the thermoplastic resin laminate at the position where it is peeled off from the last cooling roll (third cooling roll in FIG. 3) is preferably -2 ° C. or higher with respect to the glass transition temperature of the polycarbonate resin-containing layer. The temperature is preferably adjusted to -2 ° C to + 20 ° C, particularly preferably + 0.1 ° C to + 20 ° C, and most preferably + 0.1 ° C to + 15 ° C.
If the TT is too low with respect to the glass transition temperature of the polycarbonate resin-containing layer, the shape of the final cooling roll (third cooling roll in FIG. 3) is transferred to the resin plate, and the warp may increase. On the other hand, if the TT is too high with respect to the glass transition temperature of the resin layer in contact with the last cooling roll (third cooling roll in FIG. 3), the surface property of the resin plate may deteriorate.

The larger the peripheral speed ratio (V4 / V2), the more the Re value tends to increase. The reason is presumed as follows. Under the condition that the TT is adjusted to a temperature of preferably -2 ° C. or higher, more preferably -2 ° C. to + 20 ° C. with respect to the glass transition temperature of the polycarbonate resin-containing layer, the peripheral speed ratio of the take-up roll is increased and the resin plate is used. When a large tensile stress is applied to the resin, the Re value is presumed to increase because the resin molecules are in the temperature range where they are likely to be oriented.
The TT is controlled to a temperature of preferably -2 ° C. or higher, more preferably -2 ° C. to + 20 ° C. with respect to the glass transition temperature of the polycarbonate resin-containing layer, and the peripheral speed ratio (V4 / V2) is adjusted within a suitable range. By doing so, the Re value can be controlled within a suitable range. Specifically, in the production method of the present invention, the peripheral speed ratio (V4 / V2) is preferably 0.98 or more and less than 1.0. When the peripheral speed ratio (V4 / V2) is 1.0 or more, the Re value may exceed 210 nm. If the peripheral speed ratio (V4 / V2) is less than 0.98, Re may be less than 50 nm. From the viewpoint of optimizing the Re value, the peripheral velocity ratio (V4 / V2) is more preferably 0.985 to 0.995.

(Step (Y))
In the step (Y), the functionality-imparting film is attached to the surface of the resin plate prepared in the step (X).
As a method of directly forming the functional layer on the resin plate instead of the method of laminating the functional imparting film, a roll coater, a die coater, a flow coater or the like is used to form a functional material or a precursor of the functional material. Examples thereof include a method of applying a liquid coating liquid containing the coating liquid, a method of applying a liquid coating liquid containing a functional material or a precursor of the functional material by a dip method, and a vapor phase method such as a vapor deposition method. The method of directly forming the functional layer on the resin plate generally includes a step of heating the resin plate at a relatively high temperature for drying or curing of the coating liquid or vapor formation. Due to this relatively high temperature heating step, the in-plane retardation value (Re value) of the resin plate may decrease, and the Re value may be out of the preferable range.
In the present invention, as compared with the method of directly forming the functional layer on the resin plate, the bonding of the functional imparting film capable of imparting the functional layer at a lower temperature is adopted. Further, in order to suppress a decrease in the in-plane retardation value (Re value) of the resin plate due to heating, the temperature of the resin plate does not exceed 60 ° C., preferably 50 ° C., more preferably 40 ° C. Laminate under no conditions.
In the production method of the present invention, a functionalizing film can be attached to a resin plate by using an adhesive or an adhesive, if necessary. A certain amount of heat is required for bonding in order to spread the adhesive or the adhesive thinly and uniformly on the resin plate. However, the temperature of the resin plate should not exceed 60 ° C. In order to maintain the temperature of the resin plate in the bonding process at 60 ° C. or lower, an adhesive that does not require irradiation of energy rays and heating at a temperature exceeding 60 ° C. is used in the bonding process.
The temperature of the resin plate does not have to exceed 60 ° C. in the bonding step, and heating to 60 ° C. or higher during the production of the functionalizing film, for example, when forming the functional layer on the base film, is applied to the resin plate. There is no particular problem because it is not affected by.

In the manufacturing method of the present invention, by carrying out the laminating step under the condition that the resin plate does not exceed 60 ° C., the decrease in the in-plane retardation value of the resin plate in the laminating step is suppressed, and the in-plane of the resin plate is suppressed. The ratio (R2 / R1) of the in-plane retardation value (R2) of the liquid crystal display protective plate to the retardation value (R1) of is 0.9 to 1.1. When R2 / R1 is in this range, the change in the in-plane retardation value (Re value) of the resin plate in the bonding process is small, and the in-plane retardation value (R2) of the liquid crystal display protective plate is in a suitable range. It can be easily controlled within (specifically, within the range of 50 to 210 nm).
As described above, the in-plane retardation value (R3) of the base film of the functionalizing film is preferably 10 nm or less. If the in-plane retardation value (R3) of the base film is 10 nm or less and sufficiently smaller than the in-plane retardation value (R1) of the resin plate, the surface of the liquid crystal display protective plate obtained after the bonding step The retardation value (R2) in the above can be easily controlled within a suitable range (specifically, within a range of 50 to 210 nm), which is preferable.

The method for manufacturing a liquid crystal display protective plate of the present invention may have steps other than the above steps (X) and (Y), if necessary. The decrease in the in-plane retardation value of the resin plate due to heat is suppressed, and the finally obtained in-plane retardation value (R2) of the liquid crystal display protective plate is within a suitable range (specifically, 50 to 210 nm). In order to easily control the temperature within the range), it is preferable that the temperature of the resin plate does not exceed 60 ° C. in other steps as well.

As described above, according to the method for manufacturing a liquid crystal display protective plate of the present invention, the in-plane letter of the resin plate in the bonding step is performed by performing the bonding step under the condition that the resin plate does not exceed 60 ° C. A liquid crystal display having a functional layer that suppresses a decrease in the ration value (Re value), has an in-plane retardation value (R2) within a preferable range, and has good visibility of the liquid crystal display that has passed through a polarizing filter. A protective plate can be manufactured.

[Use]
Liquid crystal display protective plates are, for example, ATMs of financial institutions such as banks; vending machines; televisions; mobile information terminals (PDAs) such as mobile phones (including smartphones), personal computers, and tablet-type personal computers, digital audio players, and mobile phones. It is suitable as a protective plate for a liquid crystal display or a touch panel display used in digital information devices such as game machines, copy machines, fax machines, and car navigation systems.

Examples and comparative examples according to the present invention will be described.
[Evaluation items and evaluation methods]
The evaluation items and evaluation methods are as follows.
(MVR)
The MVR of the resin was measured according to ISO-1133 using a melt indexer (“TAKARA L241-153”, manufactured by Techno Seven Co., Ltd.).

(In-plane retardation value (Re value))
A 100 mm square test piece was cut out from a resin plate, a functionalizing film, or a liquid crystal display protective plate. After the test piece was left in an environment of 25 ° C. ± 3 ° C. for 10 minutes or more, the Re value was measured using "WPA-100 (-L)" manufactured by Photonic Lattice Co., Ltd. The measurement point was the central part of the test piece.

(Pencil hardness)
In order to evaluate the scratch resistance of the liquid crystal display protective plate having a hard coat layer (cured film) formed on the surface, a table-movable pencil scratch tester (model P, manufactured by Toyo Seiki Co., Ltd.) was used to evaluate the surface of the resin plate. The pencil scratch hardness was measured on the surface of the liquid crystal display protective plate on the hard coat layer (cured film) side. Under the conditions of an angle of 45 ° and a load of 750 g, the pencil core was pressed against the surface of the measurement target and scratched, and the presence or absence of scratches was confirmed. The hardness of the pencil lead gradually increased, and the hardness of the lead, which was one step softer than the time when the scar was generated, was used as the scratch resistance data.

(Anti-reflective)
In order to evaluate the antireflection property of the liquid crystal display protective plate having the low reflective layer formed on the surface, the spectral reflectance measuring machine (model PC-3100) was used for the resin plate and the liquid crystal display protective plate having the low reflective layer formed on the surface, respectively. , Shimadzu Corporation) was used to evaluate the lowest reflectance in the wavelength range of 380 to 780 nm. In the liquid crystal display protective plate, the surface on the low reflection layer side was irradiated with light to perform the measurement. The antireflection effect was evaluated according to the following criteria.
◯ (Good): The minimum reflectance was less than 1.5%.
Δ (possible): The minimum reflectance was 1.5% or more.

(Visibility when wearing polarized sunglasses)
A 100 mm square test piece was cut out from a resin plate or a liquid crystal display protective plate using a running saw. Next, a color liquid crystal display was placed at a position 35 cm away from the eyes to display an image. Then, the test piece was placed parallel to the screen of the display at a position 30 cm away from the eyes in front of the liquid crystal display.
First, the image was visually observed by passing the test piece in the thickness direction without wearing polarized sunglasses. Next, with the polarized sunglasses worn, the head was tilted to the left and right with the face facing the image, and the image was visually observed in the same manner as described above. Visibility was evaluated according to the following criteria.
○ (Good): There was no significant change in the appearance of the image depending on whether or not polarized sunglasses were worn, and the image could be visually recognized without any problem regardless of whether or not polarized sunglasses were worn.
X (defective): When the neck was tilted at a certain angle while wearing polarized sunglasses, the image became dark or darkly colored, and the visibility of the image deteriorated.

[material]
The materials used are as follows.
<Methacrylic resin (PM)>
(PM1) polymethyl methacrylate (PMMA), manufactured by Kuraray Co., Ltd. "Parapet (registered trademark) HR" (MVR: 2.0cm ^3/10 minutes).
<Methyl resin composition (MR)>
(MR1)
30 parts by mass of the above methacrylic resin (PM1) and 70 parts by mass of "Registfy R-200" (styrene (St) -maleic anhydride (MAH) -methyl methacrylate (MMA) copolymer) manufactured by Denki Kagaku Kogyo Co., Ltd. Was supplied to the hopper of the twin-screw extruder, melt-kneaded at a cylinder temperature of 230 ° C., and extruded to obtain a pellet-shaped methacrylic resin composition (MR1).
<Polycarbonate resin (PC)>
(PC1) by Sumika scan Tyrone polycarbonate Co., Ltd. "SD polycarbonate (registered trademark) PCX" (MVR: ^8cm 3/10 min., And a glass transition temperature: 151 ℃).

[Reference Example 1] (Manufacturing and evaluation of resin plate (RP1))
The resin plate was extruded using the manufacturing apparatus as shown in FIG.
Acrylic resin (PM1) melted using a 150 mmφ single-screw extruder (manufactured by Toshiba Machine Co., Ltd.), polycarbonate (PC1) melted using a 150 mmφ single-screw extruder (manufactured by Toshiba Machine Co., Ltd.), and 150 mmφ single-screw A methacrylic resin (PM1) melted using an extruder (manufactured by Toshiba Machine Co., Ltd.) is laminated via a multi-manifold type die, and a three-layer structure thermoplastic resin laminate is co-extruded from the T die to obtain the first -Cooling was performed using a third cooling roll, and the resin plate obtained after cooling was taken up by a pair of take-up rolls.
The first cooling roll and the third cooling roll were metal rigid rolls, and the second cooling roll was a metal elastic roll. The amount of banks formed between the first cooling roll and the second cooling roll was kept small (condition that the amount of banks was small). The peripheral speed ratio (V3 / V2) between the second cooling roll and the third cooling roll is adjusted to 1.003, and the peripheral speed ratio (V4 / V2) between the second cooling roll and the take-up roll is set to 0.995. It was adjusted. The overall temperature (TT) of the thermoplastic resin laminate at the position where the thermoplastic resin laminate is peeled off from the last cooling roll (specifically, the third cooling roll) is the temperature of the second cooling roll and the third cooling roll. Was adjusted to 130 ° C. by controlling. The measurement of TT was performed using an infrared radiation thermometer, and the measurement location was the central portion in the width direction of the resin plate.
As described above, a resin plate (RP1) having a three-layer structure having a laminated structure of a methacrylic resin-containing layer (surface layer 1) -polycarbonate resin-containing layer (inner layer) -methacrylic resin-containing layer (surface layer 2) was obtained. The composition and thickness of the two methacrylic resin-containing layers were the same. The thickness of each layer of the methacrylic resin (PM1) / polycarbonate resin (PC1) / methacrylic resin (PM1) at the central portion in the width direction of the resin plate was 75 μm / 850 μm / 75 μm. The average thickness (TC) of the entire resin plate was 1 mm, and the width of the resin plate was about 1500 mm. The obtained resin plate is cut to a length of about 1000 mm along the extrusion direction, and both ends in the width direction are cut and removed to a width of about 100 mm, respectively, and a rectangular sample resin plate of about 1000 mm × about 1300 mm is used for evaluation. Got
Table 1 shows the laminated structure of the obtained resin plates, main molding conditions, and evaluation results. In the reference examples, examples, and comparative examples shown in Tables 1 and 2, the manufacturing conditions not described were set as common conditions. In the reference example shown in Table 1, the bank amount was set to either "small" or "large". The bank amount was adjusted by changing the resin supply amount to the cooling roll, and the size of the bank amount was relatively evaluated visually.

[Reference Examples 2 to 4] (Manufacturing and evaluation of resin plates (RP2) to (RP4))
It has a laminated structure of methacrylic resin-containing layer (surface layer 1) -polycarbonate resin-containing layer (inner layer) -methacrylic resin-containing layer (surface layer 2) in the same manner as in Reference Example 1 except that the laminated structure and / or molding conditions are changed. Resin plates (RP2) to (RP4) having a three-layer structure were obtained. Table 1 shows the laminated structure of the obtained resin plates, main molding conditions, and evaluation results.

[Manufacturing Example 1-1] (Manufacturing of base film (BF1-1))
Using a composition consisting of a block copolymer of methyl methacrylate (MMA) and butyl acrylate (BA) (“Clarity” manufactured by Claret Co., Ltd.) and a methacrylic resin (PM1), a base having a thickness of 40 μm by a known method. A film (BF1-1) was produced.
[Manufacturing Example 1-2] (Manufacturing of base film (BF1-2))
A 40 μm-thick base film (BF1-2) was produced by a known method using a composition (“Parapet GR” manufactured by Kuraray Co., Ltd.) composed of crosslinked acrylic rubber particles and methacrylic resin (PM1).

[Production Examples 2-1 and 2-2] (Production of Scratch Resistant Films (F1-1) and (F1-2))
An ultraviolet curable hard coat liquid (UV-1700B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) containing urethane acrylate as a curable compound is applied to one surface of the base film (BF1-1) obtained in Production Example 1-1. Then, the coating film is cured by irradiating ultraviolet rays using an ultraviolet irradiation lamp to form a hard coat layer (cured film) having a thickness of 4 μm, and a scratch resistance imparting film (F1-1) which is a functional imparting film is formed. ) Was manufactured (Production Example 2-1). As a result of measuring the temperature of the base film with an infrared radiation thermometer at any time during the above step, the maximum temperature was about 100 ° C.
By the same method, a 4 μm-thick hard coat layer (cured film) is formed on one surface of the base film (BF1-2) obtained in Production Example 1-2 to provide a functionalizing film. A scratch-imparting film (F1-2) was produced (Production Example 2-2).

[Manufacturing Example 3] (Manufacturing of low reflectivity-imparting film (F2))
SiO ₂ sol (DTP-1 manufactured by Sumitomo Osaka Cement Co., Ltd.) was applied to one surface of the base film (BF1-1) obtained in Production Example 1-1, dried and cured by heating, and 100 nm thick. The low-reflection layer (F2), which is a functional-imparting film, was produced. As a result of measuring the temperature of the base film with an infrared radiation thermometer at any time during the above step, the maximum temperature was about 90 ° C.

[Example 1-1] (Manufacturing and evaluation of liquid crystal display protective plate)
On one surface of the resin plate (RP1) obtained in Reference Example 1, the base film side of the scratch-resistant film (F1-1) obtained in Production Example 2-1 was attached to an acrylic adhesive (CT manufactured by DIC). A liquid crystal display protective plate was manufactured by laminating at 40 ° C. using -3088).
Table 2 shows the types of the resin plate and the functionalizing film used, the temperature of the resin plate in the bonding process, the evaluation results of the used resin plate and the functionalizing film, and the evaluation results of the obtained liquid crystal display protective plate.

[Examples 1-2, 2-1 and 2-2, 3 to 7] (Manufacturing and evaluation of liquid crystal display protective plate)
A liquid crystal display protective plate was manufactured in the same manner as in Example 1-1 except that the type of the resin plate used, the functionalizing film, and the temperature of the resin plate in the bonding step were changed.
Table 2 shows the types of the resin plate and the functionalizing film used, the temperature of the resin plate in the bonding process, the evaluation results of the used resin plate and the functionalizing film, and the evaluation results of the obtained liquid crystal display protective plate.

[Comparative Example 1] (Manufacturing and evaluation of liquid crystal display protective plate)
An ultraviolet curable hard coat solution (UV-1700B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) containing urethane acrylate as a curable compound is applied to one surface of the resin plate (RP1) obtained in Reference Example 1 and irradiated with ultraviolet rays. The coating film was cured by irradiating ultraviolet rays with a lamp to form a hard coat layer (cured film) having a thickness of 4 μm. As a result of measuring the temperature of the resin plate with an infrared radiation thermometer at any time during the above step, the maximum temperature was about 100 ° C.
Table 2 shows the types of resin plates used, the main components of the coating liquid used to form the functional layer, the temperature of the resin plate in the functional layer forming process, the resin plates used and the evaluation results of the obtained liquid crystal display protective plate. Shown.

[Comparative Examples 2 to 4] (Manufacturing and evaluation of liquid crystal display protective plate)
A liquid crystal display protective plate was manufactured in the same manner as in Comparative Example 1 except that the type of resin plate used was changed.
Table 2 shows the types of resin plates used, the main components of the coating liquid used to form the functional layer, the temperature of the resin plate in the functional layer forming process, the resin plates used and the evaluation results of the obtained liquid crystal display protective plate. Shown.

[Comparative Examples 5 to 7] (Manufacturing and evaluation of liquid crystal display protective plate)
A liquid crystal display protective plate was manufactured in the same manner as in Example 1-1 except that the type of the resin plate used, the functionalizing film, and the temperature of the resin plate in the bonding step were changed.
Table 2 shows the types of the resin plate and the functionalizing film used, the temperature of the resin plate in the bonding process, the evaluation results of the used resin plate and the functionalizing film, and the evaluation results of the obtained liquid crystal display protective plate.

[Summary of results]
In Reference Examples 1 to 4, resin plates (RP1) to (RP4) having an in-plane retardation value (R1) of 50 to 210 nm could be produced by adjusting the extrusion molding conditions.
In Examples 1-1, 1-2, 2-1 and 2-2, 3 to 7, the temperature of the resin plate exceeds 60 ° C. with respect to the resin plate obtained in any of Reference Examples 1 to 4. A liquid crystal display protective plate having a functional layer was manufactured by laminating a functionalizing film under no conditions. In all of these examples, the decrease in the in-plane retardation value (Re value) of the resin plate in the bonding step was small, and all of the obtained resin plates had the in-plane retardation value of the liquid crystal display protective plate. (R2) was 50 to 210 nm. It was confirmed that all of the obtained liquid crystal display protective plates had improved pencil hardness or antireflection property as compared with those before the functionalizing film was attached, and were imparted with the desired functions. All of the obtained liquid crystal display protective plates had good visibility of the liquid crystal display through the polarizing filter.

In Comparative Examples 1 to 4, a functional layer was directly formed on the resin plate obtained in any of Reference Examples 1 to 4 without using a functionalizing film. Since it was heated to 100 ° C. in the functional layer forming step, the in-plane retardation value (Re value) of the resin plate was significantly reduced, and all the obtained resin plates had the in-plane retardation value (Re value) of the liquid crystal display protective plate. R2) was less than 50 nm. All of the obtained liquid crystal display protective plates had poor visibility of the liquid crystal display through the polarizing filter.

In Comparative Examples 5 to 7, a functional imparting film was attached to the resin plate obtained in any of Reference Examples 1 to 4 under the condition that the temperature of the resin plate exceeded 60 ° C. to form a liquid crystal display protective plate. Manufactured. In all of these comparative examples, the in-plane retardation value (Re value) of the resin plate was significantly reduced in the bonding process, and the obtained liquid crystal display protective plates were all visually recognized by the liquid crystal display through the polarizing filter. The sex was poor.

The present invention is not limited to the above-described embodiments and examples, and the design can be appropriately changed as long as the gist of the present invention is not deviated.

This application claims priority on the basis of Japanese application Japanese Patent Application No. 2017-241586 filed on December 18, 2017, and incorporates all of its disclosures herein.

1, 2 Liquid crystal display protection plate 11 T-die 12 1st cooling roll (1st cooling roll)
13 Second cooling roll (second cooling roll)
14 Third cooling roll (third cooling roll)
15 Take-up roll 16, 16X, 16Y Resin plate 17 Functionality-imparting film 21 Polycarbonate resin-containing layer 22, 22A, 22B Methacrylic resin-containing layer 23 Base film 24 Functional layer

Claims (5)

A method for manufacturing a liquid crystal display protective plate, which includes a step (X) of preparing a resin plate and a step (Y) of attaching a functionalizing film to the resin plate.
The step (Y) is carried out under the condition that the temperature of the resin plate does not exceed 60 ° C.
The in-plane retardation value (R1) of the resin plate is 50 to 210 nm.
The in-plane retardation value (R2) of the liquid crystal display protective plate is 50 to 210 nm.
The liquid crystal display protection in which the ratio (R2 / R1) of the in-plane retardation value (R2) of the liquid crystal display protection plate to the in-plane retardation value (R1) of the resin plate is 0.9 to 1.1. How to make a board. The method for manufacturing a liquid crystal display protective plate according to claim 1, wherein the resin plate is a thermoplastic resin laminate in which a methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer. Step (X) is
A step of co-extruding the thermoplastic resin laminate in which the methacrylic resin-containing layer is laminated on at least one surface of the polycarbonate resin-containing layer from a T-die in a molten state.
The molten thermoplastic resin laminate is sandwiched between the first cooling roll and the second cooling roll while forming a bank, and the thermoplastic resin laminate is wound around the second cooling roll, and then a third. The process of cooling by wrapping it around a cooling roll,
The method for manufacturing a liquid crystal display protective plate according to claim 2, further comprising a step of picking up the thermoplastic resin laminate after cooling with a pick-up roll. The functionalizing film is obtained by laminating a base film and at least one functional layer on the surface of the base film.
The method for manufacturing a liquid crystal display protective plate according to any one of claims 1 to 3, wherein the in-plane retardation value (R3) of the base film is 10 nm or less. The method for manufacturing a liquid crystal display protective plate according to claim 4, wherein the base film is made of an acrylic resin or a triacetyl cellulose-based resin.

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