JP2016004242A - Laminate and polarizing plate using the laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an active energy ray-curable adhesive that enables a (meth) acrylic resin film comprising a cross-linked elastic body and a resin film such as a polarizer to be bonded together conveniently and strongly to prepare a laminate, thereby providing an optical film laminate having excellent durability and productivity and a polarizing plate using the laminate.SOLUTION: A laminate comprises a (meth) acrylic resin film layer 3 comprising a cross-linked elastic body, an ultraviolet-curable adhesive layer 2 having a specific composition, and a polarizer layer 1.

Description

  The present invention relates to a laminate and a polarizing plate using the laminate. In particular, the present invention relates to a laminate having a (meth) acrylic resin film layer containing a crosslinked elastic body, and a polarizing plate using the laminate.

  In a liquid crystal display device, usually two polarizing plates are arranged on both sides of a liquid crystal cell. The polarizing plate generally has a polarizer protective film bonded to both sides of the polarizer, and a film made of a cellulose-based material is usually used as the polarizer protective film. In recent years, a polarizer protective film made of a (meth) acrylic material has been proposed for the purpose of improving durability.

  Adhesives or pressure-sensitive adhesives (also called pressure-sensitive adhesives) are widely used for bonding such optical films. Usually, when a film made of a cellulose-based material is bonded to a polarizer, a water-based adhesive such as a polyvinyl alcohol-based adhesive is used.

  In general, a (meth) acrylic film is poor in hydrophilicity compared to a cellulose film, and therefore, when a water-based adhesive is used for bonding with a polarizer, there is a problem that the adhesive strength is not sufficient. For this reason, it has been proposed that a (meth) acrylic film is subjected to a hydrophilic treatment (corona discharge treatment or plasma treatment) or an easy-adhesion layer is provided in order to improve adhesion (for example, Patent Document 1). However, there is a problem that performing such a process complicates the process and increases the cost.

  On the other hand, since the (meth) acrylic film has a low strength, a treatment such as biaxial stretching is performed to improve the strength, but there is still a problem that the strength is not sufficient. Therefore, the use of a (meth) acrylic resin containing a crosslinked elastic body has been studied. A film using such a (meth) acrylic resin containing a cross-linked elastic body may be inferior in adhesiveness as compared with a film not containing a cross-linked elastic body, and there is a problem that easy adhesion treatment becomes difficult. .

  In order to avoid these problems, for example, Patent Document 2 discloses an acrylic or polyurethane adhesive instead of an aqueous adhesive. Since these are bonded by wet lamination using a coating solution containing an acrylic or polyurethane adhesive and a solvent, a solvent drying step is required after bonding, and there is a problem that productivity is low.

  Furthermore, instead of these adhesives, it has been proposed to bond with an active energy ray-curable adhesive such as ultraviolet rays that does not require a solvent drying step (for example, Patent Document 3). However, the active energy ray-curable adhesive exemplified here is highly compatible with the base material, and depending on the (meth) acrylic resin film containing the crosslinked elastic body, the adhesiveness to the polarizer may be inferior.

JP 2007-127893 A Japanese Patent Application Laid-Open Publication No. 2004-144943 JP 2010-23310 A

  In view of the problems in the prior art described above, the present invention provides an active energy that can easily and firmly bond a (meth) acrylic resin film containing a crosslinked elastic body and a resin film such as a polarizer to create a laminate. An object of the present invention is to provide an optical film laminate excellent in durability and productivity and a polarizing plate using the laminate by providing a wire curable adhesive.

  As a result of extensive studies by the present inventors, the (meth) acrylic resin film containing a cross-linked elastic body and a polarizer are laminated using an ultraviolet curable adhesive having a specific composition, so that The present invention has been completed by finding out that the problems can be solved.

  That is, this invention relates to the laminated body which consists of a (meth) acrylic-type resin film layer containing a crosslinked elastic body, the ultraviolet curable adhesive layer which has a specific composition, and a polarizer layer.

  In a preferred embodiment, the ultraviolet curable adhesive is an acrylic resin.

  In a preferred embodiment, the crosslinked elastic body is a core-shell type elastic body having a core layer made of a rubber-like polymer and a shell layer made of a glass-like polymer.

In a preferred embodiment, the orientation birefringence of the (meth) acrylic resin film is −1.7 × 10 ⁻⁴ to 1.7 × 10 ⁻⁴ .

  In a preferred embodiment, the retardation value of the (meth) acrylic resin film has an in-plane retardation Δnd of 5.0 nm or less and a thickness direction retardation Rth of 20.0 nm or less.

In a preferred embodiment, the (meth) acrylic resin film has a photoelastic coefficient of −10 × 10 ⁻¹² to 10 × 10 ⁻¹² Pa ⁻¹ .

  According to another situation of this invention, the polarizing plate which has a laminated body which consists of a (meth) acrylic-type resin film layer containing a crosslinked elastic body, a ultraviolet curable adhesive layer, and a polarizer layer is provided.

  According to the present invention, a (meth) acrylic resin film containing a cross-linked elastic body and a resin film such as a polarizer can be laminated with an ultraviolet curable adhesive. An optical film laminate with good characteristics can be produced with high productivity.

1 is a schematic cross-sectional view of a polarizing plate according to one preferred embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described, but the present invention is not limited to these embodiments.

A. (Meth) acrylic resin film containing crosslinked elastic body The (meth) acrylic resin film containing crosslinked elastic body contains (meth) acrylic resin.

  The (meth) acrylic resin film is obtained, for example, by melt-extruding a resin component containing a (meth) acrylic resin as a main component.

  As said (meth) acrylic-type resin, 90 degreeC or more is preferable, as for Tg (glass transition temperature), 105 degreeC or more is more preferable, and 120 degreeC or more is further more preferable. By including a (meth) acrylic resin having a Tg of 90 ° C. or higher as a main component, it becomes excellent in heat resistance and durability.

  Any appropriate (meth) acrylic resin can be adopted as the (meth) acrylic resin. For example, poly (meth) acrylic acid ester such as polymethyl methacrylate, methyl methacrylate- (meth) acrylic acid copolymer, methyl methacrylate- (meth) acrylic acid ester copolymer, methyl methacrylate-acrylic acid ester -(Meth) acrylic acid copolymer, (meth) acrylic acid methyl-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate-cyclohexyl methacrylate copolymer) And methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, poly (meth) acrylic acid C1-6 alkyl ((meth) acrylic acid ester-based resin having an alkyl group having 1 to 6 carbon atoms) such as poly (meth) acrylic acid methyl. More preferably, a methyl methacrylate resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

  Moreover, as a (meth) acrylic resin having higher heat resistance, a (meth) acrylic resin having a glutaric anhydride structure, a (meth) acrylic resin having a lactone ring structure, and a (meth) glutimide structure (meth) Examples thereof include acrylic resins and (meth) acrylic resins having an N-substituted maleimide structure.

  Among these, (meth) acrylic resins having a glutarimide structure are particularly preferable.

  Examples of the (meth) acrylic resin having a glutarimide structure include JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, JP-A-2006-328334, and JP-A-2006. No. 337491, JP-A 2006-337492, JP-A 2006-337493, JP-A 2006-337569, JP-A 2007-009182, etc. Resin.

  The content of the (meth) acrylic resin in the (meth) acrylic resin film is preferably 50 to 100% by weight, and more preferably 50 to 99% by weight. When the content of the (meth) acrylic resin in the (meth) acrylic resin film is less than 50% by weight, heat resistance and transparency may not be sufficient.

  The (meth) acrylic resin film contains a crosslinked elastic body in order to improve the mechanical strength of the (meth) acrylic resin. Such a crosslinked elastic body is produced by a known polymerization method such as suspension polymerization, dispersion polymerization, emulsion polymerization, solution polymerization or bulk polymerization. In particular, in order to produce a crosslinked elastic body having a core-shell structure as described below, it is preferable to use a polymerization method such as suspension polymerization, dispersion polymerization, or emulsion polymerization.

  As the cross-linked elastic body, a core-shell type elastic body having a core layer made of a rubbery polymer and a shell layer made of a glassy polymer (hard polymer) is preferable. Furthermore, the core layer made of a rubbery polymer may have one or more layers made of a glassy polymer as the innermost layer or the intermediate layer.

  The Tg of the rubber-like polymer constituting the core layer is preferably 20 ° C. or less, more preferably −60 to 20 ° C., further preferably −60 to 10 ° C. If the Tg of the rubbery polymer constituting the core layer exceeds 20 ° C., the mechanical strength of the (meth) acrylic resin may not be sufficiently improved. The glassy polymer (hard polymer) constituting the shell layer has a Tg of preferably 50 ° C. or higher, more preferably 50 to 140 ° C., and still more preferably 60 to 130 ° C. When Tg of the glassy polymer constituting the shell layer is lower than 50 ° C., the heat resistance of the (meth) acrylic resin may be lowered.

  The content ratio of the core layer in the core-shell type elastic body is preferably 30 to 95% by weight, more preferably 50 to 90% by weight. The ratio of the glassy polymer layer in the core layer is 0 to 60%, preferably 0 to 45%, more preferably 10 to 40% with respect to 100% by weight of the total amount of the core layer. The content ratio of the shell layer in the core-shell type elastic body is preferably 5 to 70% by weight, more preferably 10 to 50% by weight.

  The core-shell type elastic body may contain any appropriate other component as long as the effects of the present invention are not impaired.

  Any appropriate polymerizable monomer may be used as the polymerizable monomer for forming the rubber-like polymer constituting the core layer.

  The polymerizable monomer forming the rubbery polymer preferably contains an alkyl (meth) acrylate. In 100% by weight of the polymerizable monomer that forms the rubbery polymer, the alkyl (meth) acrylate is preferably contained in an amount of 50% by weight or more, more preferably 50 to 99.9% by weight, and more preferably 60 to 99.%. More preferably, the content is 9% by weight.

  Examples of the alkyl (meth) acrylate include ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, and lauroyl. Examples thereof include alkyl (meth) acrylates having 2 to 20 carbon atoms in the alkyl group, such as (meth) acrylate and stearyl (meth) acrylate. These alkyl groups may have an alicyclic or aromatic cyclic substituent, a branched structure, or a functional group. Among these, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate and the like are preferable, butyl acrylate, 2-ethylhexyl acrylate and isononyl acrylate are more preferable. These may be used alone or in combination of two or more.

  The polymerizable monomer forming the rubbery polymer preferably contains a polyfunctional monomer having two or more vinyl groups in the molecule. Among the polymerizable monomers forming the rubber-like polymer, the polyfunctional monomer having 2 or more vinyl groups in the molecule is preferably contained in an amount of 0.01 to 20% by weight, preferably 0.1 to 20% by weight. More preferably, it is contained 0.1 to 10% by weight, more preferably 0.2 to 5% by weight.

  Examples of the polyfunctional monomer having two or more vinyl groups in the molecule include aromatic divinyl monomers such as divinylbenzene, ethylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, hexanediol di ( Alkane polyols such as (meth) acrylate, oligoethylene glycol di (meth) acrylate, trimethylolpropane di (meth) acrylate, trimethylolpropane tri (meth) acrylate, urethane di (meth) acrylate, epoxy di ( Examples thereof include (meth) acrylate and triallyl isocyanurate. Examples of the polyfunctional monomer having different reactive vinyl groups include allyl (meth) acrylate, diallyl maleate, diallyl fumarate, diallyl itaconate, and the like. Among these, ethylene glycol dimethacrylate, butylene glycol diacrylate, and allyl methacrylate are preferable. These may be used alone or in combination of two or more.

  The polymerizable monomer that forms the rubber-like polymer may include the above alkyl (meth) acrylate and another polymerizable monomer copolymerizable with a polyfunctional monomer having two or more vinyl groups in the molecule. . In the polymerizable monomer forming the rubber-like polymer, the other polymerizable monomer is preferably contained in an amount of 0 to 49.9% by weight, and more preferably 0 to 39.9% by weight.

  Examples of the other polymerizable monomer include aromatic vinyl such as styrene, vinyl toluene and α-methylstyrene, vinyl cyanide such as aromatic vinylidene, acrylonitrile and methacrylonitrile, vinylidene cyanide, methyl methacrylate and urethane acrylate. And urethane methacrylate. Moreover, as another polymerizable monomer, a monomer having a functional group such as an epoxy group, a carboxyl group, a hydroxyl group, and an amino group may be used. Specifically, examples of the monomer having an epoxy group include glycidyl methacrylate, and examples of the monomer having a carboxyl group include methacrylic acid, acrylic acid, maleic acid, and itaconic acid. Examples of the monomer having a hydroxyl group include 2-hydroxyethyl methacrylate and 2-hydroxyethyl acrylate. Examples of the monomer having an amino group include diethylaminoethyl methacrylate and diethylaminoethyl acrylate. These may be used alone or in combination of two or more.

  The polymerizable monomer forming the rubbery polymer may be used in combination with a small amount of a chain transfer agent. As such a chain transfer agent, widely known agents can be used, and examples thereof include alkyl mercaptans such as octyl mercaptan, dodecyl mercaptan, t-dodecyl mercaptan, thioglycolic acid derivatives, and the like.

  Any appropriate polymerizable monomer may be used as the polymerizable monomer forming the glassy polymer constituting the shell layer and the glassy polymer layer in the core layer.

  The polymerizable monomer forming the glassy polymer preferably contains at least one monomer selected from alkyl (meth) acrylates and aromatic vinyl monomers. In 100% by weight of the polymerizable monomer forming the glassy polymer, it is preferable that at least one selected from alkyl (meth) acrylate and aromatic vinyl monomer is included in an amount of 50 to 100% by weight, and in an amount of 60 to 100% by weight More preferably.

  As said alkyl (meth) acrylate, a C1-C8 thing of an alkyl group is preferable. These alkyl groups may have an alicyclic or aromatic cyclic substituent, a branched structure, or a functional group. Examples of such alkyl (meth) acrylates include methyl acrylate, methyl methacrylate, ethyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Among these, methyl methacrylate is particularly preferable. These may be used alone or in combination of two or more.

  Examples of the aromatic vinyl monomer include styrene, vinyl toluene, α-methyl styrene and the like. Among these, styrene is preferable. These may be used alone or in combination of two or more.

  The polymerizable monomer forming the glassy polymer may contain a polyfunctional monomer having two or more vinyl groups in the molecule. In 100% by weight of the polymerizable monomer forming the glassy polymer, the polyfunctional monomer having two or more vinyl groups in the molecule is preferably contained in an amount of 0 to 10% by weight, and contained in an amount of 0 to 8% by weight. It is more preferable that 0 to 5% by weight is contained.

  Specific examples of the polyfunctional monomer having two or more vinyl groups in the molecule include the same ones as described above.

  The polymerizable monomer forming the glassy polymer may contain the above alkyl (meth) acrylate and another polymerizable monomer copolymerizable with a polyfunctional monomer having two or more vinyl groups in the molecule. good. In 100% by weight of the polymerizable monomer forming the glassy polymer, the other polymerizable monomer is preferably contained in an amount of 0 to 50% by weight, and more preferably 0 to 40% by weight.

  Examples of the other polymerizable monomer include vinyl cyanide such as acrylonitrile and methacrylonitrile, vinylidene cyanide, alkyl (meth) acrylates other than those described above, urethane acrylate, and urethane methacrylate. Moreover, you may have functional groups, such as an epoxy group, a carboxyl group, a hydroxyl group, and an amino group. Examples of the monomer having an epoxy group include glycidyl methacrylate, and examples of the monomer having a carboxyl group include methacrylic acid, acrylic acid, maleic acid, itaconic acid, and the like, and have a hydroxyl group. Examples of the monomer include 2-hydroxy methacrylate and 2-hydroxy acrylate, and examples of the monomer having an amino group include diethylaminoethyl methacrylate and diethylaminoethyl acrylate. These may be used alone or in combination of two or more.

  Furthermore, it is also preferable to use a small amount of a known chain transfer agent similar to that used for the rubbery polymer layer as the polymerizable monomer forming the glassy polymer.

  As a manufacturing method of the core-shell type elastic body in the present invention, any appropriate method capable of manufacturing core-shell type particles can be adopted.

  For example, a polymerizable monomer forming a rubbery polymer constituting the core layer is suspended or emulsion-polymerized to produce a suspension or emulsion dispersion containing rubbery polymer particles, and then the suspension Alternatively, a core-shell type having a multilayer structure in which a polymerizable monomer that forms a glassy polymer constituting a shell layer is added to an emulsified dispersion and radically polymerized, and the surface of rubbery polymer particles is coated with the glassy polymer. The method of obtaining an elastic body is mentioned. Here, the polymerizable monomer that forms the rubber-like polymer and the polymerizable monomer that forms the glassy polymer may be polymerized in one stage, or may be polymerized in two or more stages by changing the composition ratio. Also good.

  In order to secure the physical property balance of the (meth) acrylic resin film of the present invention, it is desirable to appropriately control the structure of the core-shell type elastic body.

  As a preferable structure of the core-shell type elastic body, for example, (a) a soft and rubbery core layer and a hard and glassy shell layer are used, and the core layer is a (meth) acrylic crosslinked elastic polymer layer. (B) The rubber-like core layer has a multilayer structure having one or more glass-like layers inside, and further has a shell layer on glass outside the core layer. . By appropriately selecting the monomer species of each layer, various physical properties (mechanical properties, optical properties, particularly orientation birefringence and photoelastic coefficient) of the (meth) acrylic resin can be arbitrarily controlled. The soft rubbery layer has a polymer glass transition temperature of less than 20 ° C, preferably less than 0 ° C, and the hard glassy layer has a polymer glass transition temperature of 0 ° C or higher, preferably Is preferably 20 ° C. or higher.

  Specific examples of the more preferable structure of the core-shell type elastic body include, for example, (i) the shell layer of the core-shell type elastic body contains 3% by weight or more of alkyl acrylate, more preferably 10% by weight or more, and further preferably 15% by weight. (Ii) the shell layer of the core-shell type elastic body comprises two or more layers having different alkyl acrylate contents, and the total amount of alkyl acrylate is more preferably 10% by weight or more. Is a non-cross-linked methacrylic resin containing 15% by weight or more, (iii) a glassy weight in which the core layer of the core-shell type elastic body is polymerized with a mixture of alkyl methacrylate, polyfunctional monomer, alkyl mercaptan, and other monomers as appropriate. In the presence of the coalescence layer, acrylic acrylate, polyfunctional monomer, alkyl Having a multilayer structure in which a rubbery polymer layer is formed by polymerizing a mixture of mercaptans and other monomers as appropriate; (iv) the core layer of the core-shell type elastic body uses an organic peroxide as a redox polymerization initiator In the presence of a polymerized glassy polymer layer, it has a multilayer structure in which a polymerized rubbery polymer layer is formed using a peracid (persulfuric acid, perphosphate, etc.) as a pyrolytic initiator. The thing etc. are illustrated. Such a preferable core-shell type elastic body structural element may have only one, or two or more plural design elements may be used in combination. By having such a structure, the core-shell type elastic body can be easily dispersed well in the (meth) acrylic resin of the present invention, and there are few defects due to non-dispersion and aggregation when a film is formed. In addition, it is excellent in toughness, heat resistance, transparency and appearance, and further, whitening due to temperature change and stress is suppressed, and a film with excellent quality can be obtained.

  When the core-shell type elastic body in the present invention is produced by emulsion polymerization, suspension polymerization or the like, a known polymerization initiator can be used. Particularly preferred polymerization initiators include persulfates such as potassium persulfate, ammonium persulfate and ammonium persulfate, perphosphates such as sodium perphosphate, organic azo compounds such as azobisisobutyronitrile, cumene hydroperoxide Hydroperoxide compounds such as tertiary butyl hydroperoxide, 1,1 dimethyl-2-hydroxyethyl hydroperoxide, peresters such as tertiary butyl isopropyloxycarbonate and tertiary butyl peroxybutyrate, benzoyl peroxide, Examples thereof include organic peroxide compounds such as dibutyl peroxide and lauryl peroxide. These may be used as thermal decomposition polymerization initiators, and as redox polymerization initiators in the presence of a catalyst such as ferrous sulfate and a water-soluble reducing agent such as ascorbic acid or sodium formaldehyde sulfoxylate. It may be selected appropriately according to the monomer composition to be polymerized, the layer structure, the polymerization temperature condition, and the like.

  When the core-shell type elastic body in the present invention is produced by emulsion polymerization, it can be produced by ordinary emulsion polymerization using a known emulsifier. Known emulsifiers include, for example, anionic properties such as sodium alkyl sulfonate, sodium alkylbenzene sulfonate, sodium dioctyl sulfosuccinate, sodium lauryl sulfate, fatty acid sodium, and polyoxyethylene lauryl ether sodium phosphate. Nonionic surfactants such as surfactants, reaction products of alkylphenols, aliphatic alcohols with propylene oxide, and ethylene oxide are shown. These surfactants may be used alone or in combination of two or more. Furthermore, if necessary, a cationic surfactant such as an alkylamine salt may be used. Among these, from the viewpoint of improving the thermal stability of the obtained core-shell type elastic body, polymerization is carried out using a phosphate ester salt (alkali metal or alkaline earth metal) such as sodium polyoxyethylene lauryl ether phosphate. It is preferable to do. The core-shell type elastic latex obtained by emulsion polymerization is spray-dried or, as is generally known, coagulating the polymer by adding an electrolyte or an organic solvent as a coagulant to the latex, and appropriately heating, washing, An operation such as separation of the aqueous phase is carried out to dry the polymer, and a bulky or powdery core-shell type elastic body is obtained. As the coagulant, known ones such as water-soluble electrolytes and organic solvents can be used. However, from the viewpoint of improving the thermal stability at the time of molding of the obtained copolymer and productivity, magnesium chloride or sulfuric acid is used. It is preferable to use a magnesium salt such as magnesium or a calcium salt such as calcium acetate or calcium chloride.

  The content of the core-shell type elastic body in the (meth) acrylic resin film of the present invention preferably includes 1 to 40 parts by weight of the core-shell type elastic body with respect to 100 parts by weight of the (meth) acrylic resin. Preferably it is 2-35 weight part, More preferably, it is 3-25 weight part. When the content of the core-shell type elastic body is less than 1 part by weight, the mechanical strength of the (meth) acrylic resin is not sufficiently improved. When the content exceeds 40 parts by weight, the heat resistance of the (meth) acrylic resin is low. May decrease.

  As a preferable particle diameter of the core-shell type elastic body, the particle diameter of the soft core layer is preferably 1 to 500 nm, more preferably 10 to 400 nm, further preferably 50 to 300 nm, 70 It is especially preferable that it is -300 nm. When the particle diameter of the core layer of the core-shell type elastic body is less than 1 nm, the mechanical strength of the (meth) acrylic resin is not sufficiently improved, and when it is larger than 500 nm, the heat resistance of the (meth) acrylic resin And transparency may be impaired.

  The particle diameter of the core layer of the core-shell type elastic body was determined by measuring a film obtained by molding a compound obtained by blending a core-shell cross-linked elastic body and Sumipex EX at a weight ratio of 0:50 with a transmission electron microscope (JEM-JEM- 1200 EX), an acceleration voltage of 80 kV, and a RuO4 stained ultrathin section method were used to randomly select 100 rubber particle images from the obtained photographs, and the average value of the particle diameters was determined.

The (meth) acrylic resin film of the present invention is better as the orientation birefringence is smaller, and is preferably from −1.7 × 10 ⁻⁴ to 1.7 × 10 ⁻⁴ . By using such a resin, the retardation value of the (meth) acrylic protective film can be reduced.

The (meth) acrylic resin film of the present invention preferably has a smaller photoelastic coefficient, preferably −10 × 10 ⁻¹² to 10 × 10 ⁻¹² Pa ⁻¹ , and −4 × 10 ⁻¹² to 4 × 10 ^−12. Pa- ¹ is more preferable.

  The (meth) acrylic resin film may contain other thermoplastic resins in addition to the (meth) acrylic resin. Other thermoplastic resins include olefin polymers, vinyl halide polymers, styrene polymers, ester polymers, amide polymers, imide polymers, polycarbonate polymers, and cellulose ester polymers. Or a copolymer containing these structures.

  0-50 weight% is preferable and, as for the content rate of the other thermoplastic resin in a (meth) acrylic-type resin film, 0-30 weight% is more preferable.

  The (meth) acrylic resin film may contain any additive as necessary. Examples of additives include stabilizers such as antioxidants, light-resistant stabilizers, weather-resistant stabilizers, and heat stabilizers, ultraviolet absorbers, flame retardants, antistatic agents, fillers, plasticizers, and lubricants.

  Although there is no restriction | limiting in particular as a manufacturing method of a (meth) acrylic-type resin film, For example, a (meth) acrylic-type resin, a crosslinked elastic body, another polymer, an additive, etc. are mixed by arbitrary appropriate methods. In addition, it can be formed into a film.

  The mixing method is not particularly limited, and examples thereof include a method in which the film raw material is premixed and then melt-kneaded in a kneader or an extruder, and a method in which the film raw material is dissolved in a solvent and mixed. It is done. At the time of mixing, filter filtration may be performed using a known appropriate method in order to reduce and remove foreign substances.

  Examples of the film forming method include any appropriate film forming method such as a solution casting method, a melt extrusion method, a calendar forming method, and a compression forming method. Of these molding methods, the melt extrusion method is preferred from the balance between cost and performance.

  Examples of the melt extrusion method include a T-type die method and an inflation method. The molding temperature is preferably 150 to 350 ° C, more preferably 200 to 300 ° C.

  When film-forming by the T-type die method, a melt filter, a gear pump, and a T-type die are attached to the tip of a single screw extruder or twin screw extruder as necessary, and the molten resin extruded into a film shape is A roll-shaped film can be produced by appropriately bringing it into contact with a cooling roll, a cooling belt, a touch roll or the like and transporting and winding it while cooling.

  The (meth) acrylic resin film may be an extruded film (unstretched film) or a stretched film. The stretched film may be either a uniaxially stretched film or a biaxially stretched film. In the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used.

  The stretching temperature is preferably in the vicinity of the glass transition temperature of the thermoplastic resin composition that is the film raw material, specifically, (Tg-20 ° C) to (Tg + 100 ° C) is preferable, and (Tg) to (Tg + 50 ° C). Is more preferable. If the stretching temperature is less than (Tg−20 ° C.), the film is likely to break and stretching may not be performed sufficiently. If it exceeds (Tg + 100 ° C.), the film may melt.

  Although there is no restriction | limiting in particular in the draw ratio, 1.1 to 10 times are preferable and 1.4 to 5 times are more preferable. If the draw ratio is less than 1.1 times, the effect of improving the strength by drawing is not sufficient.

  When the (meth) acrylic resin film is a film made of a resin containing a cross-linked elastic body in a (meth) acrylic resin, since the film has excellent mechanical strength, an unstretched film, a uniaxially stretched film, Any of biaxially stretched films can be suitably used.

  The smaller the retardation value of the (meth) acrylic resin film, the better, the in-plane retardation Δnd is preferably 5.0 nm or less, the thickness direction retardation Rth is preferably 20.0 nm or less, Δnd is 2.0 nm or less, and Rth is 5 0.0 nm or less is more preferable, Δnd is 1.0 nm or less, and Rth is more preferably 3.0 nm or less. If the value of the phase difference is equal to or greater than these values, the optical characteristics may be deteriorated.

  The thickness of the (meth) acrylic resin film is preferably 5 to 200 μm, and more preferably 10 to 100 μm. When the thickness is less than 5 μm, sufficient strength cannot be obtained, and when the thickness exceeds 200 μm, the transparency is lowered and the drying of the adhesive solvent (water, etc.) is delayed, and the thickness of the polarizing plate May become thicker.

  In order to increase the affinity with the adhesive, corona discharge treatment, plasma treatment, ozone treatment, ultraviolet irradiation, flame treatment, chemical treatment, and the like may be performed. Of these, corona discharge treatment and plasma treatment are preferred.

B. Ultraviolet curable adhesive layer The ultraviolet curable adhesive layer is formed by applying an ultraviolet curable adhesive to a (meth) acrylic resin film containing a crosslinked elastic body, and then irradiating it with ultraviolet rays to cure.

  Examples of the ultraviolet curable adhesive used in the present invention include an adhesive utilizing a photo radical polymerization reaction such as a (meth) acrylate adhesive, an ene / thiol adhesive, an unsaturated polyester adhesive, and an epoxy adhesive. And an adhesive using a photocationic polymerization reaction such as an adhesive, an oxetane adhesive, an epoxy / oxetane adhesive, and a vinyl ether adhesive.

  Among these, as the ultraviolet curable adhesive used in the present invention, an adhesive utilizing a photo radical polymerization reaction is preferable, and a (meth) acrylate adhesive is more preferable.

  In the photocationic curable adhesive, examples of the curable component include an epoxy compound, a vinyl ether compound, and an oxetane compound, and among these, an epoxy compound and an oxetane compound are preferable. Furthermore, an adhesive using an epoxy compound and an oxetane compound in combination is more preferable.

  As the epoxy compound, various compounds can be used as long as they have an epoxy group. Specifically, dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl- 3,4-epoxycyclohexanecarboxylate, di (3,4-epoxycyclohexyl) adipate, bisphenol A type epoxy resin, halogenated bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol S diglycidyl ether, bisphenol F Type epoxy resin, 1,6-hexanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, compound in which both ends of polybutadiene are glycidyl etherified, o-, m P-cresol novolak type epoxy resin, phenol novolak type epoxy resin, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, polybutadiene internal epoxidation product, styrene-butadiene copolymer double bond is partially epoxidized A compound obtained by epoxidizing a part of a polyisoprene of a block copolymer of an ethylene-butylene copolymer and a polyisoprene (for example, L-207 manufactured by KRATON), 4 Examples include compounds having a structure in which a vinyl group of a ring-opening polymer of vinylcyclohexene oxide is epoxidized [for example, EHPE3150 manufactured by Daicel Chemical Industries, Ltd.] and epoxidized vegetable oil.

  As the oxetane compound, various compounds having an oxetanyl group can be used. Specifically, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, di [2- (3-Oxetanyl) butyl] ether, 1,4-bis [(3-ethyloxetane-3-yl) methoxy] benzene, 1,3-bis [(3-ethyloxetane-3-yl) methoxy] benzene, 1 , 2-bis [(3-ethyloxetane-3-yl) methoxy] benzene, 4,4′-bis [(3-ethyloxetane-3-yl) methoxy] biphenyl, 2,2′-bis [(3- Ethyl-3-oxetanyl) methoxy] biphenyl, 3,3 ′, 5,5′-tetramethyl [4,4′-bis (3-ethyloxetane-3-yl) methoxy] biphenyl, , 7-bis [(3-ethyloxetane-3-yl) methoxy] naphthalene, 1,6-bis [(3-ethyloxetane-3-yl) methoxy] -2,2,3,3,4,4, 5,5-octafluorohexane, 3 (4), 8 (9) -bis [(1-ethyl-3-oxetanyl) methoxymethyl] -tricyclo [5.2.1.02.6] decane, 1,2 -Bis [2-[(1-ethyl-3-oxetanyl) methoxy] ethylthio] ethane, 4,4′-bis [(1-ethyl-3-oxetanyl) methyl] thiodibenzenethioether, 2,3-bis [ (3-Ethyloxetane-3-yl) methoxymethyl] norbornane, 2-ethyl-2-[(3-ethyloxetane-3-yl) methoxymethyl] -1,3-O-bis [(1-ethyl-3 -Oxetanyl) L] -propane-1,3-diol, 2,2-dimethyl-1,3-O-bis [(3-ethyloxetane-3-yl) methyl] -propane-1,3-diol, 2-butyl- 2-ethyl-1,3-O-bis [(3-ethyloxetane-3-yl) methyl] -propane-1,3-diol, 1,4-O-bis [(3-ethyloxetane-3-yl ) Methyl] -butane-1,4-diol, 2,4,6-O-tris [(3-ethyloxetane-3-yl) methyl] cyanuric acid, bisphenol A and 3-ethyl-3-chloromethyloxetane ( OXC)) etherified product (BisAOX), bisphenol F and OXC etherified product, phenol novolak and OXC etherified product, cresol novolak and OXC etherified product, oxetani Silsesquioxane and 3-ethyl-3-hydroxymethyl oxetane of silicon alkoxide and the like.

  These compounds may be used alone or in combination of two or more.

  As the photocationic polymerization initiator used in the photocationic curable adhesive, various compounds can be used as long as they generate an acid capable of cationic polymerization upon irradiation with ultraviolet rays.

  Specific examples thereof include onium salts such as diazonium salts, iodonium salts, sulfonium salts, selenium salts, pyridinium salts, ferrocenium salts, phosphonium salts, and thiopyrinium salts.

  In the present invention, the composition becomes excellent in curability, and the cured product has less yellowing, and the photocationic polymerization initiator is a sulfonium salt such as an aromatic sulfonium salt or a dialkylphenacylsulfonium salt. Are preferred, more preferred are aromatic sulfonium salts, and particularly preferred are triarylsulfonium salts.

  When an onium salt photocationic polymerization initiator such as an iodonium salt or a sulfonium salt is used, examples of the anion include BF4-, AsF6-, SbF6-, PF6-, and B (C6F5) 4-, preferably SbF6-. And PF6-. The cationic photopolymerization initiator is available as a commercial product.

Examples of the triarylsulfonium salt include Dow Chemical Japan Co., Ltd., Syracure UVI-6990, UVI-6922, UVI-6974, etc., Asahi Denka Kogyo Co., Ltd. Adekaoptomer SP-150, SP-152, Examples thereof include SP-170 and SP-172, and WPAG-593, WPAG-596, WPAG-640, and WPAG-641 manufactured by Wako Pure Chemical Industries, Ltd.
Examples of aromatic iodonium salts include GE Toshiba Silicone UV-9380C, Rhodia PHOTOINITITOR 2074, Wako Pure Chemical Industries, Ltd. WPI-016, WPI-116, and WPI-113, Ciba Specialty Chemicals Co., Ltd. IRGACURE250 manufactured by the company is mentioned.

  In the present invention, by using a photocationic polymerization accelerator in combination, the curability of the composition can be increased or the adhesive strength of the cured product can be improved. Examples of the photocationic polymerization accelerator include a photoradical polymerization initiator that generates radicals upon irradiation with ultraviolet light, and a photocationic polymerization sensitizer.

  Examples of the radical photopolymerization initiator include the same as those described below.

  Examples of the cationic photopolymerization sensitizer include anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone, acridone derivatives such as N-methylacridone and N-butylacridone, anthracene, and 9,10-dialkoxyanthracene. , 9-alkoxyanthracene, anthracene derivatives, perylene, phenothiazine and the like. These may be used alone or in combination.

  In order to produce the optical film laminate of the present invention, an ultraviolet curable adhesive containing a compound containing a radical polymerizable reactive group is preferable because of high productivity, and transparency and weather resistance are also good. For this reason, an ultraviolet curable (meth) acrylate adhesive is preferable.

  The (meth) acrylate adhesive will be further described in detail. The (meth) acrylate adhesive contains a monomer or oligomer having one or more (meth) acryloyl groups in the molecule and a radical photopolymerization initiator as essential components. The (meth) acrylate-based adhesive may further contain an additive or the like as necessary.

  Monomers having one or more (meth) acryloyl groups in the molecule include monofunctional acrylic monomers having one (meth) acryloyl group in the molecule, and two or more (meth) acryloyl groups in the molecule. The polyfunctional acrylic monomer which has can be mention | raise | lifted.

  Examples of monofunctional acrylic monomers include isooctyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, and methoxytriethylene glycol (meth) acrylate. , (Meth) acrylate, 2-ethylhexyl carbitol (meth) acrylate, ethoxyethyl (meth) acrylate, tricyclodecane (meth) acrylate, dicyclopentenyl (meth) acrylate, isobornyl (meta) ) Acrylate, adamantyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) Acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, N- (meth) acryloyloxyethyl hexahydrophthalimide, ω-carboxypolycaprolactone Examples include (meth) acrylate, monohydroxyethyl phthalate (meth) acrylate, and (meth) acrylic acid dimer.

  Examples of polyfunctional acrylic monomers include neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol hydroxypivalic acid di (meth) acrylate, and caprolactone-modified neopentyl glycol hydroxypivalic acid. Di (meth) acrylate, alkylene oxide modified neopentyl glycol di (meth) acrylate, alkylene oxide modified 1,6-hexanediol di (meth) acrylate, neopentyl glycol modified trimethylolpropane di (meth) acrylate, polyethylene glycol di ( (Meth) acrylate, polypropylene glycol di (meth) acrylate, tricyclodecane dimethylol di (meth) acrylate, dicyclopentanyl di ( Acrylate), trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, aliphatic modified dipentaerythritol penta (meth) acrylate having 2 to 5 carbon atoms, aliphatic modified dipenta having 2 to 5 carbon atoms Erythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, pentaerythritol tetra (meth) acrylate, tris [(meth) acryl Roxyethyl] isocyanurate, caprolactone-modified tris [(meth) acryloxyethyl] isocyanurate, ditrimethylolpropane tetra (meth) acrylate, etc. .

  Examples of the oligomer having one or more (meth) acryloyl groups in the molecule include epoxy (meth) acrylate, polyester (meth) acrylate, and urethane (meth) acrylate.

  Epoxy (meth) acrylate is obtained by reaction of an epoxy resin and (meth) acrylic acid. Examples of the epoxy resin include bisphenol type epoxy resins such as bisphenol A type epoxy resin and bisphenol F type epoxy resin, and novolak type epoxy resins. Examples of the bisphenol A type epoxy resin include Epicoat 827 (trade name, the same applies hereinafter), Epicoat 828, Epicoat 1001, Epicoat 1004, etc. manufactured by Japan Epoxy Resin Co., Ltd. Etc. Examples of the novolak type epoxy resin include Epicoat 152 and Epicoat 154.

  Polyester (meth) acrylate is obtained by reaction of polyester polyol and (meth) acrylic acid. The polyester polyol is obtained by a reaction between a polyhydric alcohol and a polybasic acid. Examples of the polyhydric alcohol include neopentyl glycol, ethylene glycol, propylene glycol, 1,6-hexanediol, trimethylolpropane, pentaerythritol, tricyclodecane dimethylol, bis- [hydroxymethyl] -cyclohexane and the like. Examples of the polybasic acid include succinic acid, phthalic acid, hexahydrophthalic anhydride, terephthalic acid, adipic acid, azelaic acid, tetrahydrophthalic anhydride and the like.

  Urethane (meth) acrylates can be obtained by three-way reaction of polyol, organic polyisocyanate and hydroxy (meth) acrylate compound, or two of organic polyisocyanate and hydroxy (meth) acrylate compound without using polyol Those obtained by the reaction of Polyols include polyether polyols such as polypropylene glycol and polytetramethylene glycol, polyester polyols obtained by the reaction of the polyhydric alcohol and the polybasic acid, and the reaction of the polyhydric alcohol, the polybasic acid and ε-caprolactone. And a polycarbonate polyol (for example, a polycarbonate polyol obtained by a reaction of 1,6-hexanediol and diphenyl carbonate). Examples of the organic polyisocyanate include isophorone diisocyanate, hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, diphenylmethane-4,4'-diisocyanate, and dicyclopentanyl diisocyanate. Those obtained by the reaction of the three parties or those obtained by the reaction of the two parties may be used alone, or both may be used in combination.

  As a monomer having a (meth) acryloyl group used in the present invention, lauryl (meth) acrylate, stearyl (meth) acrylate, (meth) acrylate of an alkylene oxide modified product of a phenol derivative, from the viewpoints of viscosity and solubility, 2-ethylhexyl carbitol (meth) acrylate, ethoxyethoxyethyl (meth) acrylate, tricyclodecane (meth) acrylate, dicyclopentenyl (meth) acrylate, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2- Hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, etc. are preferred. Among them, lauryl (meth) acrylate, (meth) acrylate of phenol derivative modified with alkylene oxide, isobornyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (Meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxy-3-phenoxypropyl (meth) acrylate are particularly preferred.

  As the oligomer having a (meth) acryloyl group used in the present invention, urethane (meth) acrylate is particularly preferably used. As the polyol to be used, polyether polyol, caprolactone polyol, polycarbonate polyol and the like are preferable from the viewpoint of heat resistance and water resistance. Moreover, as organic polyisocyanate, isophorone diisocyanate, xylene diisocyanate, etc. are preferable from points, such as heat resistance.

  The radical photopolymerization initiator which is the other essential component of the (meth) acrylate adhesive will be described in detail. The photoradical polymerization initiator is a compound that generates a radical that is a polymerization initiating species by irradiation with ultraviolet rays.

  Examples of the radical photopolymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 2-methyl-1- [4- (methylthio)] phenyl] -2. -Acetophenone photopolymerization initiators such as morpholinopropan-1-one, benzoin photopolymerization initiators such as benzoin, benzoin ether, benzyldimethyl ketal, benzoin alkyl ether, benzophenone, benzoylbenzoic acid, phenylbenzophenone, hydroxybenzophenone, etc. Benzophenone photopolymerization initiators, thioxanthone photopolymerization initiators such as thioxanthone, chlorothioxanthone, methylthioxanthone, ethylthioxanthone, propylthioxanthone, fluorothioxanthone, glyoxy Ester ethers, acyl oxime esters, acylphosphine oxides, bisacylphosphine oxides, and the like.

  In order to further increase the reactivity of the (meth) acrylate adhesive, an aromatic amine such as an aliphatic amine or Michler's ketone, diethylaminophenone, ethyl dimethylaminobenzoate, or isoacyldimethyldimethylbenzoate is used as a photopolymerization initiation assistant. It can also be added as.

  Adhesives include compounds having radically polymerizable reactive groups other than (meth) acryloyl groups, polymer polymers, plasticizers, silane coupling agents, polymerization inhibitors, leveling agents, surface lubricants, erasing agents as necessary. Additives such as foaming agents, light stabilizers, antioxidants, antistatic agents and fillers can be incorporated.

  Examples of the compound having a radical polymerizable reactive group other than (meth) acryloyl group include N-vinylpyrrolidone, N-vinylformamide, N-vinylcaprolactone, acryloylmorpholine, N, N-dimethylacrylamide, N-isopropylacrylamide, N , N-diethylacrylamide, N-hydroxyethylacrylamide, 2-acrylamido-2-methylpropanesulfonic acid and the like. Among these compounds, N-vinylpyrrolidone, acryloylmorpholine, and N, N-dimethylacrylamide have low viscosity and high solubility, and can be suitably used in the present invention.

  Examples of the polymer include polyester-based, polycarbonate-based, polyacrylic-based, polyurethane-based, and polyvinyl-based resins.

  Examples of the plasticizer include dioctyl phthalate, diisononyl phthalate, dioctyl adipate, tricresyl phosphate, epoxidized soybean oil, trioctyl trimellitic acid, chlorinated paraffin, and the like. Examples of the silane coupling agent include alkyl-based, amine-based, (meth) acrylate-based, isocyanate-based, epoxy-based, and thiol-based agents. Examples of the polymerization inhibitor include methoquinone, methylhydroquinone, phenothiazine and the like. Examples of the leveling agent, surface lubricant, and antifoaming agent include organic polymer-based, silicon-based, and fluorine-based agents. Examples of the antioxidant include hindered amines, hindered phenols, and polymer phenols. Examples of the antistatic agent include quaternary ammonium type, polyether type, and conductive powder. Examples of the filler include silica gel, titanium oxide, alumina, and conductive powder. The amount of these additives used is appropriately determined within the above range according to the purpose.

  In the present invention, the ultraviolet curable adhesive is cured by irradiation with ultraviolet rays. Various ultraviolet rays can be used.

  Although the ultraviolet light source is not particularly limited, for example, sunlight, low-pressure mercury lamp, medium-pressure mercury lamp, high-pressure mercury lamp, ultra-high pressure mercury lamp, metal halide lamp, etc. can be used. Mercury lamps and metal halide lamps are preferred.

  As a form of ultraviolet irradiation, there are a sample conveyance type in which ultraviolet irradiation is performed while a sample is conveyed, and a sample fixing type in which the sample is irradiated in a fixed state. In the present invention, any method can be selected, but a sample transport type having a transport mechanism such as a conveyor is preferable in terms of productivity and area increase.

  Although there is no restriction | limiting in particular in the irradiation of the ultraviolet-ray in this invention, It is preferable that the peak illumination intensity in 365 nm is 1000 mW / cm <2> or less, and 600 mW / cm <2> or less is more preferable. When the peak illuminance exceeds 1000 mW / cm 2, there is a possibility that each film is thermally deformed or the absorbance of the polarizing plate is lowered. Further, the integrated light quantity is preferably 400 mJ / cm 2 or more, and more preferably 600 mJ / cm 2 or more. If the integrated light quantity is 400 mJ / cm 2 or less, the adhesiveness becomes insufficient and the laminate may be peeled off.

  The peak illuminance is the maximum value of illuminance at the time of ultraviolet irradiation. In particular, in the case of the sample conveyance type, since the sample passes under the ultraviolet light source, if the relationship between the irradiation time and the illuminance is graphed, a convex mountain shape is formed, and the peak is the peak illuminance. Further, the integrated light amount is a product of illuminance and irradiation time, and when the relationship between irradiation time and illuminance is graphed, the area is the integrated light amount.

  In order to change the ultraviolet illuminance, it is generally used to change the output of the lamp, change the distance between the lamp and the sample, or arrange a filter between the lamp and the sample. Further, in order to change the integrated light quantity, it is necessary to change the illuminance or the irradiation time or both.

  Heat may be applied simultaneously with ultraviolet irradiation to promote curing, but in any case, the surface temperature of the laminate is preferably kept at about room temperature, more preferably not exceeding 50 ° C. . When the surface temperature of a laminated body exceeds 50 degreeC, a linearly-polarizing plate and a resin film may deform | transform and may impair the external appearance of a laminated body.

C. 1 is a schematic sectional view of a laminate according to a preferred embodiment of the present invention.

  The laminate 4 is obtained by laminating the polarizer 1, the adhesive layer 2, and the (meth) acrylic resin film 3 in this order.

C-1. Polarizer As the polarizer 1, for example, a uniaxially stretched film obtained by adsorbing a dichroic substance such as iodine or a dichroic dye on a hydrophilic film such as a polyvinyl alcohol film is preferably used. Although there is no restriction | limiting in particular in the thickness of these polarizers, it is about 1-80 micrometers.

  A polarizer uniaxially stretched by adsorbing iodine to a polyvinyl alcohol film is produced, for example, by immersing polyvinyl alcohol in an iodine aqueous solution and then stretching.

  The polyvinyl alcohol film may be washed with water before dyeing as necessary. Occurrence of uneven dyeing can be prevented by washing the polyvinyl alcohol film with water.

  Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching.

C-2. Adhesive Layer As an adhesive for forming the adhesive layer 2, B.I. The suitable ultraviolet curable adhesive illustrated in (1) can be used.

  In order to further improve the adhesiveness, various coupling agents and tackifiers may be added to the adhesive. As the coupling agent, a silane coupling agent is preferable. In addition, an ultraviolet absorber, an antioxidant, a heat stabilizer, a hydrolysis stabilizer, and the like may be added.

  The thickness of the adhesive layer formed from the adhesive composition is set according to the composition of the adhesive composition and the like. 10-300 nm is preferable and 20-150 nm is especially preferable from an adhesive viewpoint.

C-3. (Meth) acrylic resin film The (meth) acrylic resin film 4 is obtained by melt-extruding a resin component containing a (meth) acrylic resin as a main component, as described above.
C-4. Other
When using a 2nd protective film as a polarizing plate, arbitrary appropriate protective films can be used. Representative examples of the material forming the second protective film include cellulose polymers such as triacetyl cellulose and cycloolefin polymers. The 2nd protective film may be formed with the material similar to said (meth) acrylic-type resin film. The second protective film and the polarizer are bonded with any appropriate adhesive.

D. Manufacturing method Arbitrary appropriate methods can be employ | adopted as a manufacturing method of the laminated body of this invention. Hereinafter, one embodiment will be described. The polarizer and the (meth) acrylic resin film are laminated via an adhesive layer.

  As described above, at least one side of the (meth) acrylic resin film (side on which the polarizer is disposed) can be subjected to surface treatment as necessary. In this case, the surface treatment described above is performed before forming the adhesive layer. The surface treatment is preferably corona discharge treatment or plasma treatment. By performing the corona discharge treatment, the adhesion and adhesion between the polarizer and the (meth) acrylic resin film can be further improved. The corona discharge treatment is performed under any appropriate conditions. For example, the corona discharge electron dose is preferably 50 to 150 W / m 2 / min, more preferably 70 to 100 W / m 2 / min.

  The polarizer and the (meth) acrylic resin film are laminated via an adhesive layer. Specifically, after applying the adhesive composition on one side of either the polarizer or the (meth) acrylic resin film, the polarizer and the (meth) acrylic resin film are bonded together and dried. Is mentioned. Examples of the method for applying the adhesive composition include a roll method, a spray method, and an immersion method. The drying temperature is typically 5 to 150 ° C, preferably 30 to 120 ° C. The drying time is typically 120 seconds or longer, preferably 300 seconds or longer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited by these Examples. In addition, the evaluation method of a (meth) acrylic-type resin film is as follows.

<Optical characteristics>
The in-plane retardation Δnd and the thickness direction retardation Rth were measured using KOBRA-WR manufactured by Oji Scientific Instruments. Visible light transmittance (total light transmittance) was measured using a Nippon Denshoku Industries Co., Ltd. haze meter (HAZE METER).

<Adhesion strength>
A T-type peel test was performed in accordance with JIS K 6854.

(Production Example 1)
<Manufacture of cross-linked elastic body>
A mixture of the following composition was charged into a glass reactor, heated to 80 ° C. while stirring in a nitrogen stream, and then a monomer mixture consisting of 25 parts of methyl methacrylate and 1 part of allyl methacrylate and t-butyl hydro 25% of the mixed solution with 0.1 part of peroxide was charged all at once, and polymerization was performed for 45 minutes.
220 parts deionized water
Boric acid 0.3 parts
Sodium carbonate 0.03 parts Sodium N-lauroyl sarcosinate 0.09 parts Sodium formaldehyde sulfoxylate 0.09 parts Ethylenediaminetetraacetic acid-2-sodium 0.006 parts Ferrous sulfate 0.002 parts

  Subsequently, the remaining 75% of the mixture was continuously added over 1 hour. After completion of the addition, the polymerization was completed by maintaining at the same temperature for 2 hours. During this period, 0.2 part of sodium N-lauroyl sarcosinate was added. The polymerization conversion rate (polymerization amount / monomer charge amount) of the obtained innermost layer crosslinked methacrylic polymer latex was 98%.

  The innermost layer polymer latex thus obtained was kept at 80 ° C. in a nitrogen stream, and after adding 0.1 part of potassium persulfate, a single unit consisting of 41 parts of n-butyl acrylate, 9 parts of styrene, and 1 part of allyl methacrylate. The monomer mixture was added continuously over 5 hours. During this time, 0.1 part of potassium oleate was added in three portions. After completing the addition of the monomer mixture, 0.05 part of potassium persulfate was further added and held for 2 hours in order to complete the polymerization. The resulting rubber particles had a polymerization conversion rate of 99% and a particle size of 225 nm.

  The obtained rubber particle latex was kept at 80 ° C., 0.02 part of potassium persulfate was added, and then a monomer mixture of 14 parts of methyl methacrylate and 1 part of n-butyl acrylate was continuously added over 1 hour. After completion of the addition of the monomer mixture, the mixture was held for 1 hour to obtain a graft copolymer latex. The polymerization conversion rate was 99%.

  The obtained graft copolymer latex was kept at 80 ° C., and a monomer mixture of 5 parts of methyl methacrylate and 5 parts of n-butyl acrylate was continuously added over 0.5 hours. The rubber-containing graft copolymer latex was obtained by holding for 1 hour after the addition of the monomer mixture was completed. The polymerization conversion rate was 99%. The obtained rubber-containing graft copolymer latex was subjected to salting out coagulation, heat treatment, and drying with calcium chloride to obtain a white powdery crosslinked elastic body.

(Manufacture of (meth) acrylic resin film)
Pellets of 90 parts by weight of parapet HR-S {copolymerization monomer weight ratio = methyl methacrylate / methyl acrylate = 99/1} and 10 parts by weight of the crosslinked elastic body obtained in Production Example 1 are supplied to a biaxial extruder. And melt extruded into a sheet at about 280 ° C. to obtain a film having a thickness of 100 μm. This unstretched film was stretched 1.6 times in length and 1.6 times in width under a temperature condition of 130 ° C. to obtain a (meth) acrylic resin film (thickness 40 μm, in-plane retardation Δnd 0.8 nm, thickness direction) A phase difference Rth of 1.5 nm was obtained.

(Bonding of PVA and (meth) acrylic resin film)
The adhesive composition LVA-5 (manufactured by Arakawa Chemical Industries, Ltd.) was applied to the (meth) acrylic resin film so that the thickness after drying was 50 nm. Thereafter, a polyvinyl alcohol film Boblon-EX (film thickness: 12 μm) and a (meth) acrylic protective film made by Nippon Synthetic Chemical are laminated through an adhesive composition, and the following conditions are satisfied with an ultraviolet ray irradiation apparatus made by Eye Graphics. The layered product was obtained by UV irradiation.
Peak intensity: 335 mW / cm 2
Integrated light quantity: 790 mJ / cm2
Light source: Metal halide lamp

  A polyvinyl alcohol film and a (meth) acrylic resin film were bonded in the same manner as in Example 1 except that the side of the (meth) acrylic film in contact with the adhesive was subjected to corona treatment.

(Corona discharge treatment)
One side of the (meth) acrylic resin film was subjected to corona discharge treatment (corona discharge electron irradiation amount: 77 W / m 2 / min).

  A polyvinyl alcohol film and a (meth) acrylic resin film were bonded in the same manner as in Example 1 except that RC29-322 (manufactured by DIC) was used as the adhesive composition.

  A polyvinyl alcohol film and a (meth) acrylic resin film were bonded in the same manner as in Example 1 except that Z-5822-1 (manufactured by Aika Kogyo Co., Ltd.) was used as the adhesive composition.

(Comparative Example 1)
As an adhesive composition, 100 parts by weight of an acetoacetyl group-containing polyvinyl alcohol resin (average polymerization degree: 1200, saponification degree: 98.5 mol%, acetoacetyl group modification degree: 5 mol%) is 100% by weight of methylolmelamine 20 A polyvinyl alcohol film and a (meth) acrylic resin film were prepared in the same manner as in Example 1 except that the weight part was dissolved in pure water at a temperature of 70 ° C. and an aqueous solution having a solid content of 1.0% was used. Pasted.

  As is clear from Table 1, the laminates produced in the examples were excellent in adhesion, but the laminates produced in the comparative examples were inferior in adhesion. From this, it is clear that an optical film laminate excellent in durability and productivity can be obtained by using an ultraviolet curable adhesive.

  The polarizing plate of the present invention can be suitably used for image display devices such as liquid crystal display devices and self-luminous display devices.

1 Polarizer 2 Adhesive Layer 3 (Meth) Acrylic Resin Film 4 Polarizing Plate

Claims (6)

  A laminate comprising a (meth) acrylic resin film layer containing a crosslinked elastic body, an ultraviolet curable adhesive layer, and a polarizer layer.   The laminate according to claim 1, wherein the crosslinked elastic body is a core-shell type elastic body having a core layer made of a rubber-like polymer and a shell layer made of a glass-like polymer. The (meth) orientation birefringence of the acrylic resin film is 1.7 × ^{10 -4} from -1.7 × ^{10 -4,} the laminated body according to any one of claims 1-2.   The retardation value of the (meth) acrylic protective film has an in-plane retardation Δnd of 5.0 nm or less and a thickness direction retardation Rth of 20.0 nm or less. Laminated body. The laminated body as described in any one of Claims 1-4 whose photoelastic coefficient of the said (meth) acrylic-type resin film has -10 * 10 <^-12> to 10 * 10 <^-12> Pa < ^{-1 >} .   The polarizing plate which has a laminated body as described in any one of Claims 1-5.

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