JP2007279234A - Method for producing optical member with pressure-sensitive adhesive layer, optical member with pressure-sensitive adhesive layer and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an optical member with a pressure-sensitive adhesive layer excellent in anchoring power to the optical member and excellent also in adhesive durability in a high temperature and high humidity environment. <P>SOLUTION: In the method for producing the optical member 1 with the pressure-sensitive adhesive layer, a photosetting pressure-sensitive adhesive composition layer comprising a photosetting pressure-sensitive adhesive composition 2 which contains (b) 0.01-5 pts.wt. of a polyfunctional vinyl monomer and (c) 0.01-1 pt.wt. of a hydrogen abstraction type radical polymerization photoinitiator, based on (a) 100 pts.wt. of a monomer consisting mainly of 70-99 pts.wt. of an alkyl (meth)acrylate having a 1-14C alkyl group and 1-30 pts.wt. of a vinyl monomer having a polar group, is formed on at least one surface of an optical member, and a pressure-sensitive adhesive layer is formed for the optical member 1 by irradiation with light. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an optical member with an adhesive layer in which an adhesive layer is laminated on at least one surface of an optical member, and an optical member with an adhesive layer. Furthermore, the present invention relates to an image display device such as a liquid crystal display device, an organic EL display device, or a PDP using the optical member with the pressure-sensitive adhesive layer. Examples of the optical member include a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and a laminate of these.

  An optical member used for a liquid crystal display device or the like, such as a polarizing plate or a retardation plate, is attached as an optical member with an adhesive layer in which an adhesive layer is laminated when being attached to a liquid crystal cell. Since the material used for the optical member has a large expansion and contraction under heating and humidification conditions, it tends to float and peel off after being attached. Therefore, there is a demand for a pressure-sensitive adhesive for optical members that can be used even under heating and humidification conditions.

  In addition, when an optical member is attached, a liquid crystal cell, which is an expensive member, is usually peeled off from the liquid crystal cell when a foreign object bites into the bonding surface or the bonding position is misplaced. Will be reused. When such an optical member is peeled from the liquid crystal cell, there is no adhesive residue and the adhesive state does not change or break the liquid crystal cell, that is, the optical member can be easily peeled off. Peelability (reworkability) is required.

  However, when a pressure-sensitive adhesive with an emphasis on durable adhesive force is designed, the adhesive force between the optical member and the pressure-sensitive adhesive layer tends to be insufficient because the pressure-sensitive adhesive layer has a high degree of crosslinking. Therefore, when the optical member expands or contracts under heating conditions or humidification conditions, floating or peeling occurs between the optical member and the adhesive.

  On the other hand, if the design focusing on the anchoring force between the optical member and the pressure-sensitive adhesive layer is used, the pressure-sensitive adhesive layer has a low degree of cross-linking, resulting in insufficient durability and problems such as foaming and floating. To do.

  In order to solve such problems, a method has been proposed in which the surface of the pressure-sensitive adhesive layer is subjected to surface activation treatment such as corona treatment and bonded to an optical member such as a polarizing plate or a retardation plate (patent) Reference 1). According to this method, it is disclosed that the anchoring force between the pressure-sensitive adhesive layer and the optical member is improved, but it does not yet have a sufficient anchoring force level.

  In addition, a method of applying a polyester aqueous dispersion of a specific component on a polyester film before orientation crystallization is completed is disclosed (Patent Document 2). According to this method, it is disclosed that the anchoring force for a polyester film and various coatings applied thereon is improved.

  In addition, as a primer layer, there is a coating layer (Patent Document 3) in which a water-insoluble copolyester and a water-insoluble acrylic resin are independently dispersed as individual particles, and both resins are uniformly dispersed in water. It is disclosed. According to this coating layer, it is disclosed that a high anchoring force for a wide range of paints is improved.

  Further, a pressure-sensitive adhesive sheet with a foamed base material in which a crosslinked primer made of an acrylic polymer having an amino group and an epoxy compound is interposed between a foamed base material mainly composed of a chlorine-containing elastomer and an adhesive layer ( Patent document 4) is disclosed. In this method, it is disclosed that the adhesive layer can be stably used for a long time without impairing the anchoring force of the pressure-sensitive adhesive layer on the base material even under a high temperature environment.

  As examples of the anchor coat layer, a polyacryl ester layer (Patent Document 5), a polyester resin layer (Patent Document 6), an ultraviolet curable epoxy acrylate layer (Patent Document 7), an acrylic resin emulsion, and a polyurethane resin emulsion were used. Although the layer (Patent Document 8) is mentioned, the anchoring force is greatly influenced by the type of the optical member and the type of the pressure-sensitive adhesive, and in many cases, sufficient anchoring force cannot be expressed.

  In addition, the method of providing a single primer between the base material and the pressure-sensitive adhesive layer to improve the anchoring force requires a more complicated manufacturing process than applying the pressure-sensitive adhesive layer directly on the base material. The adhesive strength between the adhesive layer and the pressure-sensitive adhesive layer is not sufficiently improved.

  On the other hand, a method of heat-treating a polarizing plate before bonding an adhesive layer to the polarizing plate has been proposed (Patent Document 9). According to such a method, it is possible to reduce the residual solvent in the triacetyl cellulose that is the protective film of the polarizing plate, which is a factor that hinders the reaction of the isocyanate compound that is the crosslinking agent in the pressure-sensitive adhesive layer. It is disclosed that the cross-linking degree of the agent layer is stabilized and the anchoring force between the pressure-sensitive adhesive layer and triacetyl cellulose is improved.

  Moreover, when bonding the adhesive layer containing an isocyanate type crosslinking agent to the polarizing plate which uses triacetyl cellulose as a protective film, the bonding temperature is set to 50 to 70 ° C., and the bonding temperature is 1 to 40 to 50 ° C. after the bonding. A method of curing for 24 hours has been proposed (Patent Document 10). According to this method, it is disclosed that the anchoring force between the pressure-sensitive adhesive layer and triacetyl cellulose is improved.

  In the methods according to Patent Document 9 and Patent Document 10, the types of pressure-sensitive adhesives and optical members are limited, and even if the methods described in these patent documents are applied to combinations of other pressure-sensitive adhesives and optical members, sufficient investment is possible. There are many cases where force cannot be expressed.

  In addition, when an optical member such as a polarizing plate or a phase difference plate is bonded to an adhesive, it is strongly required that peeling does not occur even under a high temperature and high humidity condition, that is, a high durability adhesive force is required. Various attempts have been made to improve the pressure-sensitive adhesive used to solve the above problems.

  As a means for enhancing the durable adhesive strength of the pressure-sensitive adhesive layer under high temperature and high humidity, a method of crosslinking the pressure-sensitive adhesive layer is generally known, but sufficient curing time is required to completely complete the gelation. There was a problem that productivity was lowered.

  Moreover, in order to balance foaming and peeling of the pressure-sensitive adhesive layer due to shrinkage of the optical member at high temperature, there is a method of increasing the molecular weight of the solvent-type acrylic pressure-sensitive adhesive used for the pressure-sensitive adhesive layer. There was a problem that the viscosity increased and the coating property of the pressure-sensitive adhesive decreased.

  Among these, 100 parts by weight of acrylic monomer, 5 to 200 parts by weight of acrylic high molecular weight polymer having a weight average molecular weight of 100,000 or more, 0.01 to 2 parts by weight of polymerization photoinitiator, and a crosslinking agent, After casting an acrylic pressure-sensitive adhesive composition substantially free of water and solvent on a support such as a release film, and forming a pressure-sensitive adhesive layer on the support by light irradiation, the pressure-sensitive adhesive layer is A manufacturing method for obtaining an optical member with an adhesive layer by transferring to an optical member is disclosed (Patent Document 11).

  However, since the pressure-sensitive adhesive layer is produced by the above-described transfer process, the adhesive strength of the pressure-sensitive adhesive layer to the optical member, that is, the anchoring force is insufficient, and throwing and breaking at the interface between the optical member and the adhesive layer tends to occur. Met.

  Also disclosed is a method of directly applying an alcohol-soluble UV-curable pressure-sensitive adhesive layer to an optical member such as a polarizing plate or a retardation plate (Patent Document 12).

As described above, various methods have been tried to improve the anchoring force between the pressure-sensitive adhesive layer and the optical member and the durability adhesive force under high temperature and high humidity, but both methods are compared with the case where the method is not performed. Then, although it is improved to some extent, there is a case where the effect is not obtained at all when the adhesive is changed or depending on the type of the optical member.
JP-A-7-174918 Japanese Patent Publication No. 4-73466 JP-A-6-293875 JP 7-331194 A Japanese Patent Laid-Open No. 10-20118 JP 2003-49148 A JP-A-6-265723 JP 2003-307624 A Japanese Patent Laid-Open No. 9-227841 JP-A-11-199838 Japanese Patent Laid-Open No. 2002-241707 JP-A-2-137922

  The present invention has been made in view of the above-described conventional problems, and is excellent in the anchoring force of the pressure-sensitive adhesive layer to the optical member and has an excellent adhesive strength under high temperature and high humidity. It aims at providing the manufacturing method of.

  As a result of intensive studies to achieve the above object, the present inventors have formed a photocurable pressure-sensitive adhesive composition layer composed of a photocurable pressure-sensitive adhesive composition on one surface of an optical member, and are irradiated by light irradiation. In the method for obtaining an optical member with an adhesive layer, it was found that by using a photocurable adhesive composition having a specific polymerization photoinitiator, an optical member with an adhesive layer that achieves the above problems can be obtained. Completed the invention. That is, the present invention is as follows.

  1. (A) For 100 parts by weight of a monomer mainly composed of 70 to 99 parts by weight of an alkyl (meth) acrylate having 1 to 14 carbon atoms in the alkyl group and 1 to 30 parts by weight of a vinyl monomer having a polar group, (B) A photocurable pressure-sensitive adhesive composition comprising 0.01 to 5 parts by weight of a polyfunctional vinyl monomer and (c) 0.01 to 1 part by weight of a hydrogen abstraction type radical polymerization photoinitiator. A method for producing an optical member with a pressure-sensitive adhesive layer, comprising forming a photocurable pressure-sensitive adhesive composition layer on at least one surface of an optical member, and forming a pressure-sensitive adhesive layer on the optical member by irradiating light.

  2. 2. The method for producing an optical member with an adhesive layer according to claim 1, wherein (c) the hydrogen abstraction type radical polymerization photoinitiator is a benzophenone-based or thioxanthone-based radical polymerization photoinitiator.

  3. The method for producing an optical member with an adhesive layer according to claim 1 or 2, wherein the optical member is made of a resin film constituting a retardation plate or a polarizing plate.

  4). (A) a step of partially polymerizing the component (a) to obtain a monomer mixture containing a partial polymer, and (b) 0.01 to 1 part by weight of a polyfunctional vinyl monomer in the monomer mixture And (c) 0.01 to 1 part by weight of a hydrogen abstraction type radical polymerization photoinitiator to prepare a photocurable pressure-sensitive adhesive composition (B) to prepare a photocurable pressure-sensitive adhesive composition. The manufacturing method of the optical member with an adhesive layer in any one of Claims 1-3 characterized by the above-mentioned.

  5. The pressure-sensitive adhesive according to claim 4, wherein in the step (A) of obtaining the monomer mixture containing the partial polymer, the proportion of the partial polymer in the monomer mixture is 10 to 40% by weight. A method for producing a layered optical member.

  6). In the step (A) of obtaining a monomer mixture containing the partial polymer, a radical polymerization photoinitiator different from the component (c) is added to the component (a), and the single polymer containing the partial polymer is irradiated by light irradiation. A method for producing an optical member with an adhesive layer according to claim 4 or 5, wherein a mixture of monomers is obtained.

  7). The multifunctional vinyl monomer is added so that the insoluble fraction of the pressure-sensitive adhesive layer is 5 to 70% by weight, The optical member with the pressure-sensitive adhesive layer according to any one of claims 1 to 6 Production method.

  8). The optical member with an adhesive layer obtained by the manufacturing method of the optical member with an adhesive layer in any one of Claims 1-7.

  9. The anchoring force between the adhesive layer and the optical member of the optical member with the adhesive layer is 20 (N / 25 mm) or more, and the optical member with the adhesive layer is attached to the bakelite plate with a contact area of 10 mm × 20 mm. The deviation distance (mm) after 1 hour when a load of 500 g is applied after being allowed to stand at 80 ° C. for 30 minutes is 0.2 (mm) or less. The optical member with an adhesive layer of description.

  10. An image display device using at least one optical member with an adhesive layer according to claim 8 or 9.

  According to the method for producing an optical member with an adhesive layer of the present invention, an optical member with an adhesive layer having excellent anchoring force between the adhesive layer and the optical member and having a high durability adhesive force under high temperature and high humidity. Obtainable.

  The reason why an optical member for an adhesive layer excellent in anchoring force between the adhesive layer and the optical member is obtained by the method for producing an optical member with an adhesive layer of the present invention is not clear, but prior to polymerization, photocurable type Since the pressure-sensitive adhesive composition layer is formed on the optical member, the formed photocurable pressure-sensitive adhesive composition layer follows the minute irregularities on the surface of the optical member and is reliably applied to the surface of the optical member. Since the photocurable pressure-sensitive adhesive composition layer is polymerized by photopolymerization to form a pressure-sensitive adhesive layer, the adhesion between the pressure-sensitive adhesive layer and the optical member is improved, and the anchoring force is effectively increased. Seem.

  Further, when the photocurable pressure-sensitive adhesive composition layer is irradiated with light by the hydrogen abstraction type radical polymerization photoinitiator contained in the pressure-sensitive adhesive layer of the present invention, the hydrogen abstraction type radical polymerization photoinitiator is It is considered that radicals are generated, and the radicals extract hydrogen from the polymer forming the surface of the optical member to cause a radical initiation reaction.

  Starting from this initiation reaction, the intermolecular cross-linking reaction between the pressure-sensitive adhesive layer and the optical member proceeds, and the anchoring force between the pressure-sensitive adhesive layer and the optical member is effectively increased. It is presumed that the durable adhesive strength can be increased.

  Hereinafter, the configuration of the present invention will be described in detail.

  The manufacturing method of the optical member with an adhesive layer of this invention is 1-30 weight part of vinyl monomers which have (a) C1-C14 alkyl (meth) acrylate 70-99 weight part and a polar group in an alkyl group. (B) 0.01 to 5 parts by weight of a polyfunctional vinyl monomer, and (c) 0.01 to 1 part by weight of a hydrogen abstraction type radical polymerization photoinitiator, A photocurable pressure-sensitive adhesive composition layer comprising a photocurable pressure-sensitive adhesive composition comprising: an optical member; The manufacturing method of the optical member with an adhesive layer which forms a layer, and an optical member with an adhesive layer are related.

  Examples of the alkyl (meth) acrylate as the component (a) include methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, 2-ethylhexyl, isooctyl, isononyl, and isodecyl. Straight chain or branched having 1 to 20, preferably 4 to 18 carbon atoms such as a group, dodecyl group, lauryl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicodecyl group And those using one or more esters of acrylic acid or methacrylic acid having an alkyl group.

  Moreover, there is no limitation in particular as a vinyl monomer which has a polar group contained in (a) component, What is necessary is just to be copolymerizable with the said alkyl (meth) acrylate.

  Specific examples include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid and other carboxyl group-containing monomers; maleic anhydride, itaconic anhydride Acid anhydride monomers such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, (meth) Hydroxyl group-containing monomers such as 8-hydroxyoctyl acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl (meth) acrylate; styrene sulfonic acid, Allyl sul Sulfonic acid group-containing monomers such as acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate, (meth) acryloyloxynaphthalenesulfonic acid; Phosphoric acid group-containing monomers such as hydroxyethyl acryloyl phosphate; Amide monomers such as (meth) acrylamide, N-methylolacrylamide, acryloylmorpholine; N- (meth) acryloyloxymethylenesuccinimide, N- (meth) acryloyl-6-oxy Succinimide monomers such as hexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide; vinyl acetate, N-vinyl pyrrolidone, N-vinyl carboxylic acid amide , Vinyl monomers such as styrene and N-vinylcaprolactam; acrylonitrile, methacrylonitrile, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, fluorine ( Examples include acrylate monomers such as (meth) acrylate, silicone (meth) acrylate, and 2-methoxyethyl acrylate.

  The composition of the monomer (a) is 70 to 99 parts by weight of alkyl (meth) acrylate and 30 to 1 weight of vinyl monomer having a polar group with respect to 100 parts by weight of the total amount of the monomer (a). It is made to contain in the ratio of a part. Preferably, the alkyl (meth) acrylate is 80 to 99 parts by weight, the vinyl monomer having a polar group is 20 to 1 part by weight, more preferably, the alkyl (meth) acrylate is 90 to 98 parts by weight, and the vinyl monomer having a polar group is 10 It is contained at a ratio of ˜2 parts by weight.

  In addition, the photocurable pressure-sensitive adhesive composition before photopolymerization is prepared in advance so as to adjust the viscosity of the photocurable pressure-sensitive adhesive composition to a viscosity suitable for coating. In addition, the monomer mixture obtained by the step (A) of partially photopolymerizing a vinyl monomer having a polar group to obtain a monomer mixture containing a partial polymer may be used. Alternatively, a thickening polymer can be blended.

 In order to partially photopolymerize the alkyl (meth) acrylate as the component (a) and the vinyl monomer having a polar group, a polymerization photoinitiator can be added to the component (a). Although a general polymerization photoinitiator can be used as the polymerization photoinitiator used for this, it is preferable to use a radical polymerization photoinitiator different from the component (c) described later.

  Specifically, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone (Irgacure 907 made by Ciba Geigy), benzyldimethyl ketal (Irgacure 651 made by Ciba Geigy), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184 made by Ciba Geigy), diethoxyacetophenone (First Cure DEAP made by First Chemical), 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocur 1173 made by Ciba Geigy), 1- (4-isopropylphenyl) ) -2-hydroxy-2-methylpropan-1-one (Darocur 1116), 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one (Darocur 953), 4- (2- Hydro Ciethoxy) phenyl (2-hydroxy-2-propyl) ketone (Irgacure 2959 from Ciba Geigy) and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone (Irgacure 369 from Ciba Geigy), 4 Acetophenones such as phenoxydichloroacetophenone, 4-t-butyl-dichloroacetophenone, 4-t-butyl-trichloroacetophenone, diethoxyacetophenone, mixed photoinitiator (Darocur 2273), acrylic ketone-containing photoinitiator (Darocur 1664), etc. -Based polymerization photoinitiators; benzoin ether-based polymerization photoinitiators such as benzoin methyl ether, benzoin isopropyl ether and 2,2-dimethoxy-1,2-diphenylethane-1-one; anisole methyl ether Any substituted benzoin ether polymerization photoinitiators; substituted acetophenone polymerization initiators such as 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxy-cyclohexyl-phenylketone; 2-methyl- Substituted alpha ketol polymerization initiators such as 2-hydroxypropiophenone; aromatic sulfonyl chlorides such as 2-naphthalenesulfonyl chloride; 1-phenyl-1,1-propanedione-2- (o-ethoxycarbonyl) -oxime, etc. The photoactive oxime can be used.

  Here, as the polymerization photoinitiator used when partially photopolymerizing the monomer mixture, it is not preferable to use the hydrogen abstraction type radical polymerization photoinitiator as the component (c). This is because the hydrogen abstraction reaction proceeds from the partially polymerized product, which may increase the molecular weight and cause gelation.

  The polymerization photoinitiator used when partially photopolymerizing the vinyl monomer having an alkyl (meth) acrylate and a polar group is 0.01 to 5 parts by weight with respect to 100 parts by weight of the monomer. Added. More preferably, it is used in a ratio of 0.03 to 3 parts by weight, and more preferably 0.03 to 1 part by weight.

  When the addition amount of the polymerization photoinitiator is decreased, the polymerization rate as a partially polymerized product is too low. Conversely, when the addition amount is too large, the polymerization rate may be too high.

  The proportion of the partial polymer in the monomer mixture is preferably 10 to 40% by weight, more preferably 10 to 30% by weight, still more preferably 15 to 25% by weight, based on the monomer mixture. It is. When a plurality of these polymerization photoinitiators are used, all of them are added in the above ratio.

  The weight average molecular weight of the partially polymerized product is 100,000 to 5,000,000, preferably 500,000 to 3,000,000, and more preferably 800,000 to 2,000,000.

  On the other hand, as the polymer for thickening used to adjust the photocurable pressure-sensitive adhesive composition to a viscosity suitable for coating, the monomer (a) is copolymerized with acrylic acid, acrylamide, acrylonitrile, acryloylmorpholine and the like. Acrylic polymer, styrene butadiene rubber (SBR), isoprene rubber, styrene butadiene block copolymer (SBS), ethylene-vinyl acetate copolymer, acrylic rubber, polyurethane, polyester and the like can be used.

  These thickening polymers are used in an amount of 40 parts by weight or less based on 100 parts by weight of the monomer (a). Preferably it is used in the range of 5 to 40 parts by weight.

  Next, as the polyfunctional vinyl monomer as the component (b) to be added as the photocurable pressure-sensitive adhesive composition, for example, trimethylolpropane tri (meth) acrylate, tripropylene glycol diacrylate, pentaerythritol di (meth) Acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate 1,2-ethylene glycol di (meth) acrylate, 1,6-hexanediol (meth) diacrylate, 1,12-dodecanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, Scan phenol A diglycidyl ether diacrylate, tetraethylene glycidyl Koji acrylate, the like hydroxypivalic acid neopentyl glycol diacrylate, and it is of course not limited thereto.

  In the present invention, the amount of the polyfunctional vinyl monomer as the component (b) in the photocurable pressure-sensitive adhesive composition is a monomer mixture containing the monomer or partial polymer of the component (a). It is used in the range of 0.01 to 5 parts by weight, preferably 0.03 to 3 parts by weight, and more preferably 0.03 to 1 part by weight with respect to 100 parts by weight.

  When the polyfunctional vinyl monomer is used in such a range, a good cohesive force can be maintained even in a high temperature environment and the holding power is improved, but the invention is not limited to this range.

  If the content of the polyfunctional vinyl monomer is too small, sufficient cohesive force under high temperature conditions cannot be obtained. If the content is too large, the crosslink density increases and peeling becomes easy.

  The amount of the polyfunctional vinyl monomer that is component (b) in the photocurable pressure-sensitive adhesive composition varies slightly depending on the number of functional groups, but the photocurable pressure-sensitive adhesive composition is substantially polymerized. It is preferable to add so that the insoluble fraction of the pressure-sensitive adhesive layer when completed is 5 to 70% by weight, preferably 10 to 60% by weight, more preferably 20 to 50% by weight.

  The insoluble fraction is obtained by weighing a polymerized cured product, putting it in ethyl acetate, leaving it at room temperature for one week or more, taking out only the insoluble matter, and drying and removing the solvent contained in the insoluble matter. , Weighed, insoluble fraction = insoluble weight / initial weight × 100 (% by weight).

  Next, a hydrogen abstraction type radical polymerization photoinitiator is used as (c). The radical polymerization photoinitiator generates radicals by light irradiation, pulls out hydrogen from a hydrogen donor, and causes a radical initiation reaction.

  Examples of the hydrogen abstraction type radical polymerization photoinitiator (c) include benzophenone, benzoylbenzoic acid, methyl o-benzoylbenzoate, 4-methylbenzophenone, 4-phenylbenzophenone, hydroxybenzophenone, acrylated benzophenone, and 4-phenyl. Benzophenone, 4-benzoyl-4′-methyl-diphenyl sulfide, 3,3′-dimethyl-4-methoxybenzophenone and 2,4,6-trimethylbenzophenone (trade name “ESACURE TZT” manufactured by Nippon Sebel Hegner) , 4- (13-acryloyl-1,4,7,10,13-pentaoxatridecyl) (manufactured by Daicel Cytec Co., Ltd., trade name “Ebecryl P36”)-benzophenone-based polymerization photoinitiators such as benzophenone; Thioxant 2-chlorothioxanthone (manufactured by Nippon Sebel Hegner Co., Ltd., trade name “SPEEDCURE CTX”), 3-methylthioxanthone, 2,4-dimethylthioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4- Examples include thioxanthone polymerization photoinitiators such as diisopropylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and 2-methylthioxanthone, but are not limited thereto. Use things.

  The hydrogen abstraction type radical polymerization photoinitiator (c) is 0.01 to 5 parts by weight, preferably 100 parts by weight of the monomer mixture containing the monomer or partial polymer as the component (a). Is used in the range of 0.03 to 3 parts by weight, more preferably 0.03 to 1 part by weight. In order to develop a sufficient anchoring force for the optical member of the pressure-sensitive adhesive layer by light irradiation, the amount is preferably 0.1 parts by weight or more.

  In addition to the above, the photocurable pressure-sensitive adhesive composition has optional components such as an isocyanate group, an epoxy group, an aziridinyl group, an oxazoline group, and a carbodiimide group that can react with the polar functional group of the polar group-containing monomer. Various conventionally known additives such as a crosslinkable compound having a group, a tackifier, a plasticizer, a softener, a filler, a pigment, a dye, and an anti-aging agent, as long as the photopolymerization by light irradiation is not inhibited. Can be blended.

  In this invention, after forming the photocurable adhesive composition layer which consists of a photocurable adhesive composition prepared in this way on one surface of an optical member, it photopolymerizes by irradiating light.

  As the optical member, those used for forming an image display device such as a liquid crystal display device are used, and the type thereof is not particularly limited. For example, the optical member includes a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. Examples thereof include polyene-based oriented films such as those obtained by adsorbing an active substance and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products.

  Among these, a polarizer made of a dichroic material such as a polyvinyl alcohol film and iodine is preferable. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length.

  If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  In addition to washing polyvinyl alcohol film surface stains and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there.

  Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is preferable.

  For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film can also be formed as a cured layer of an acrylic, urethane, acrylic urethane, epoxy, silicone, or other thermosetting or photocurable resin.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing an unsubstituted phenyl and a thermoplastic resin having a nitrile group.

  A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of a resin composition or the like can be used.

  The thickness of the protective film can be appropriately determined, but is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

  Moreover, it is preferable that the protective film is as colored as possible. Therefore, Rth = [(nx + ny) / 2−nz] · d (where nx and ny are the main refractive index in the film plane, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a retardation value in the film thickness direction of −90 nm to +75 nm is preferably used.

  By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +60 nm, and particularly preferably −70 nm to +45 nm.

  As the protective film, a cellulose polymer such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. A triacetyl cellulose film is particularly suitable.

  In addition, when providing a protective film on both sides of a polarizer, the protective film which consists of the same polymer material may be used for the front and back, and the protective film which consists of a different polymer material etc. may be used.

  The polarizer and the protective film are usually in close contact with each other via an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a treatment for the purpose of hard coat layer, antireflection treatment, antisticking, diffusion or antiglare.

  Hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film is applied to a cured film excellent in hardness, sliding properties, etc. with an appropriate photo-curing resin such as acrylic or silicone. It can be formed by a method of adding to the surface of the film.

  The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. Or by adding a fine concavo-convex structure on the surface of the transparent protective film by an appropriate method such as a blending method of transparent fine particles.

  Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like having an average particle diameter of 0.5 to 70 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, and the like are used.

  When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  The optical member of the present invention includes, for example, a liquid crystal display device such as a reflection plate, a semi-transmission plate, a phase difference plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, and a brightness enhancement film. What becomes an optical layer which may be used for formation is mention | raise | lifted.

  These can be used alone as the optical member of the present invention, and can be used by laminating the polarizing plate for practical use, or one or more layers.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on a plate, or a polarizing plate in which a brightness enhancement film is further laminated on a polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned.

  The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one surface of a transparent protective film matted as necessary.

  In addition, the transparent protective film may contain fine particles to form a surface fine uneven structure, and a reflective layer having a fine uneven structure on the surface. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness.

  In addition, the transparent protective film containing fine particles has an advantage that incident light and its reflected light are diffused when passing through it and light and dark unevenness can be further suppressed.

  The reflective layer with a fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film can be formed by, for example, an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a deposition method or a plating method. It can be performed by a method of directly attaching to the surface of the protective layer.

  The reflection plate can be used as a reflection sheet in which a reflection layer is provided on an appropriate film according to the transparent film instead of the method of directly applying to the transparent protective film of the polarizing plate.

  Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectivity from being lowered by oxidation, and thus to maintain the initial reflectivity for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer.

  A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed.

  In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light.

  In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done.

  Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film, and a liquid crystal polymer alignment layer supported by the film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary copolymer, graft copolymer Examples thereof include polymers and blends. These polymer materials become an oriented product (stretched film) by stretching or the like.

  Examples of the liquid crystalline polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. It is done.

  Specific examples of the main chain type liquid crystalline polymer include, for example, a nematic alignment polyester liquid crystalline polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogen group is bonded to a spacer portion that imparts flexibility. .

  Specific examples of the side chain type liquid crystalline polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment imparting paraffin through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogen moiety composed of a substituted cyclic compound unit.

  These liquid crystalline polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or by obliquely depositing silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination.

  Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them sequentially in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflective) polarizing plate and a retardation plate. An optical member such as a polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of excellent quality stability and lamination workability.

  The viewing angle compensation film is a film for widening the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. Examples of such a viewing angle compensation phase difference plate include a phase difference plate, an alignment film such as a liquid crystal polymer, and an alignment layer such as a liquid crystal polymer supported on a transparent substrate.

  A normal retardation film uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation film used as a viewing angle compensation film is biaxially stretched in the plane direction. Polymer films with birefringence, biaxially stretched films such as polymers with birefringence with a controlled refractive index in the thickness direction that are uniaxially stretched in the plane direction and also stretched in the thickness direction, etc. Used.

  Examples of the inclined alignment film include a film obtained by bonding a heat-shrinkable film to a polymer film and stretching or / and shrinking the polymer film under the action of the shrinkage force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. Can be mentioned.

  The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  Also, from the point of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which an optically anisotropic layer composed of a liquid crystal polymer alignment layer, particularly a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without passing through the predetermined polarization state. The

  The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer provided behind the brightness enhancement film and re-entered on the brightness enhancement film, and a part or all of the light is transmitted as light in a predetermined polarization state. Luminance can be improved by increasing the amount of light that passes through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer.

  That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly, resulting in a dark image.

  The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer or the like provided on the rear side thereof. Repeatedly re-entering the brightness enhancement film, and the brightness enhancement film transmits only the polarized light whose polarization direction is such that the polarization direction of the light reflected and inverted between the two can pass through the polarizer. Therefore, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate can also be provided between the brightness enhancement film and the reflective layer. The light in the polarization state reflected by the brightness enhancement film is directed to the reflection layer or the like, but the installed diffusion plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarization state and becomes a non-polarization state.

  That is, the diffuser plate returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the natural light state is directed to the reflection layer and the like, reflected through the reflection layer and the like, and again passes through the diffusion plate and reenters the brightness enhancement film.

  In this way, by providing a diffuser plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., while maintaining the brightness of the display screen, at the same time reducing the unevenness of the brightness of the display screen, A uniform and bright screen can be provided. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayered thin film of dielectric material or a multilayered laminate of thin film films having different refractive index anisotropies. Such as a cholesteric liquid crystal polymer alignment film or an alignment liquid crystal layer that is supported on a film substrate, and reflects light of either left-handed or right-handed circular polarization and transmits other light. Appropriate things, such as a thing, can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is directly incident on the polarizing plate with the polarization axis aligned, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made.

  On the other hand, in a brightness enhancement film of a type that emits circularly polarized light such as a cholesteric liquid crystal layer, it can be incident on the polarizer as it is, but from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable to make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. A phase difference layer, for example, a phase difference layer that functions as a half-wave plate, can be used to superimpose. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as a visible light region by combining two or more layers having different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or more optical layers as in the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or transflective polarizing plate and a retardation plate are combined may be used.

  The optical member in which the optical layer is laminated on the polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of a liquid crystal display device or the like can be improved because of excellent stability and assembly work.

  For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  Below, the manufacturing method of the optical member with an adhesive layer of this invention is demonstrated, referring FIG.1 and FIG.2. It is not limited to the manufacturing method of these FIG.1 and FIG.2.

  The manufacturing method of the optical member with an adhesive layer of this invention is the process (1) of forming a photocurable adhesive composition layer on an optical member, and forms an adhesive layer with respect to the said optical member by light irradiation. A step (2) of performing, and a drying step (3) of the pressure-sensitive adhesive layer formed on the optical member.

(Step (1) of forming a photocurable pressure-sensitive adhesive composition layer)
FIGS. 1A to 1C and FIGS. 2A to 2C show a process of forming a photocurable pressure-sensitive adhesive composition layer on an optical member.

  In FIG. 1A, reference numeral 1 denotes an optical member. In FIG. 1B, 2 indicates a photocurable pressure-sensitive adhesive composition layer. (B) of FIG. 1 has shown the process of laminating | stacking the photocurable adhesive composition layer 2 by apply | coating a photocurable adhesive composition directly on the optical member 1. FIG.

  In FIG. 1C, reference numeral 3 denotes a peeling film. (C) of FIG. 1 has shown the process of bonding the peeling film 3 further on the photocurable adhesive composition layer 2 laminated | stacked on the optical member 1 in said (b).

  On the other hand, FIG. 2 has shown the other example which forms a photocurable adhesive layer in an optical member. In FIG. 2A, reference numeral 3 denotes a peeling film. In FIG. 2B, 2 indicates a photocurable pressure-sensitive adhesive composition layer. (B) of FIG. 2 shows the process of forming the photocurable adhesive composition layer 2 on the peeling film 3 by applying the photocurable adhesive composition layer 2 on the peeling film 3. ing.

  In FIG. 2C, 1 indicates an optical member. (C) of FIG. 2 has shown the process of bonding and laminating the optical member 1 on the photocurable adhesive composition layer 2 formed on the peeling film 3 in said (b).

  Here, the coating method of the photocurable pressure-sensitive adhesive composition in the step (1) of forming the photocurable pressure-sensitive adhesive composition layer is not particularly limited, and a normal method can be adopted. Examples thereof include a slot die method, a reverse gravure coating method, a micro gravure method, a dip method, a spin coating method, a brush coating method, a roll coating method, and a flexographic printing method.

  As a coater used at the time of application, any coating method such as a commonly used reverse coater, roll coater such as a gravure coater, curtain coater, lip coater, die coater, knife coater can be adopted.

  As the release film 3, a film that blocks oxygen and transmits light, for example, a film in which a release agent such as silicone is coated on a film such as polyethylene terephthalate can be used.

  As another method not using the peeling film 3, light irradiation can be performed in an inert gas atmosphere such as nitrogen gas instead of using the peeling film 3 shown in FIG. In this case, the photocurable pressure-sensitive adhesive composition layer 2 in FIG. 1 (d), which will be described later, in the state shown in FIG. 1 (b) without being bonded to the release film 3 shown in FIG. 1 (c). Can be irradiated with light.

  In an inert gas atmosphere, it is desirable that oxygen is not present as much as possible, and the oxygen concentration is preferably 5000 ppm or less. When the amount of dissolved oxygen is large, the amount of radicals generated is suppressed, the polymerization does not proceed sufficiently, and the resulting polymer polymerization rate, molecular weight and molecular weight distribution may be adversely affected.

(Step (2) of forming an adhesive layer on the optical member by light irradiation)
In FIG.1 and FIG.2 (d), 4 has shown light irradiation. FIG. 1 and FIG. 2 (d) show the light from the upper surface side of the peeling film 3 in a state where the peeling film 3 is bonded to the photocurable pressure-sensitive adhesive composition layer 2 formed on the optical member 1. The process of irradiating 4 is shown.

  Moreover, (e) of FIG. 1 and (e) of FIG. 2 have shown the layer containing the adhesive layer 6 obtained by hardening the photocurable adhesive composition 2 by the light irradiation 4. FIG.

  In the present invention, the light irradiation 4 is usually performed by ultraviolet irradiation. For the ultraviolet lamp used for ultraviolet irradiation, electromagnetic radiation having a spectral distribution in the wavelength range of 180 to 460 nm, preferably in the wavelength range of 300 to 400 nm is used, but electromagnetic radiation having a longer wavelength or shorter wavelength may be used. Good.

  Examples of ultraviolet light sources include general lamps such as chemical lamps, black lights (manufactured by Toshiba Lighting & Technology Corp.), mercury arcs, carbon arcs, low pressure mercury lamps, medium / high pressure mercury lamps, ultrahigh pressure mercury lamps, metal halide lamps, etc. Is used.

  The light illuminance in the present invention is set to the target illuminance by adjusting the distance from the light lamp to the photocurable pressure-sensitive adhesive composition and the voltage, and is specifically determined by the method disclosed in JP-A-2003-13015. In addition, the light irradiation in each step is divided into a plurality of stages, whereby the adhesion performance can be adjusted more precisely.

That is, the light irradiation in the present invention includes a first step of performing light irradiation with a light illuminance of 30 mW / cm ² or more, and then a second step of performing light irradiation with a light illuminance lower than that of the first step to substantially complete the polymerization reaction. The polymerization rate of the pressure-sensitive adhesive layer of the photocurable pressure-sensitive adhesive composition is at least 70% by the method or the first step of performing light irradiation with a light illuminance of 30 mW / cm ² or more, and then light irradiation with a light illuminance lower than that of the first step. The second step is followed by a method of performing a third step of substantially completing the polymerization reaction by irradiating with light having an illuminance of 30 mW / cm ² or more.

  Of these, light lamps such as low-pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, metal halide lamps, etc. are used for light irradiation in the first and third steps, and chemical lamps are used for light irradiation in the second step. A light lamp such as a black light is used.

  The light illuminance of light in each step is set to the target illuminance by adjusting the distance from the light lamp to the photocurable adhesive composition and the voltage.

  In addition, the light irradiation in each process is divided into a plurality of stages, whereby the adhesive performance can be adjusted more precisely.

(Drying process (3) of the pressure-sensitive adhesive layer formed on the optical member)
In the present invention, a pressure-sensitive adhesive layer containing substantially no unreacted monomer can be formed by the light irradiation, but when the unreacted monomer remains, an optical part with a pressure-sensitive adhesive layer is added as necessary. Unreacted monomer can be removed by heating and drying.

  FIG. 1 (f) and FIG. 2 (f) show a drying process of the pressure-sensitive adhesive layer formed on the optical member. Moreover, (f) of FIG. 1 and (f) of FIG. 2 have shown the state which peeled the peeling film 3 from the adhesive layer 6 obtained by the said light irradiation (2).

  Reference numeral 5 indicates heating. In the present invention, unreacted monomers that have not been cured by light irradiation can be removed from the pressure-sensitive adhesive layer 6 by this drying step.

  The method of heating 5 in the main drying step (3) is not particularly limited, and normal heating means can be employed. For example, a hot air fan, an electric heater, an IR heater, etc. are mentioned. Usually, drying temperature is about 20-150 degreeC, Preferably it is the range of 20-130 degreeC. The drying time is about 10 to 300 seconds, preferably 30 to 180 seconds.

  In FIG.1 (g) and FIG.2 (g), 7 has shown the optical member with an adhesive layer.

  This invention provides the optical member with an adhesive layer obtained by the manufacturing method of the said optical member with an adhesive layer, and an image display apparatus using at least one this.

  The anchoring force for the pressure-sensitive adhesive layer of the optical member with the pressure-sensitive adhesive layer is 20 N / 25 mm or more, preferably 21 N / 25 mm or more, and more preferably 22 N / 25 mm or more. In addition, the optical member with the adhesive layer was attached to a bakelite plate with a contact area of 10 mm × 20 mm, left standing at 80 ° C. for 30 minutes, and then a displacement distance after 1 hour when a load of 500 g was applied ( mm) is 0.2 (mm) or less, preferably 0.1 (mm) or less.

  By making such a range, since the anchoring force between the pressure-sensitive adhesive layer and the optical member is excellent, for example, it is possible to provide an optical member that has excellent reworkability and can withstand use under high temperature and high humidity. it can.

  Next, specific examples of the present invention will be described. However, it goes without saying that the present invention is not limited to these examples.

Example 1
To a mixed monomer solution consisting of 95 parts by weight of 2-ethylhexyl acrylate and 5 parts by weight of acrylic acid as a vinyl monomer having a polar group, 2,2-dimethoxy-1,2-diphenylethane-1-one (manufactured by Ciba-Gaiky Corp.) A solution containing 0.05 parts by weight of a trade name “IRGACURE 651” and 0.05 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone (Ciba Gaiky Co., Ltd., trade name “IRGACURE 184”) was added to a four-necked flask. And a monomer containing 20% by weight of a partially polymerized product having a weight average molecular weight of 1.4 million by heating to a constant internal bath temperature of 60 ° C. in a nitrogen atmosphere and exposing it to ultraviolet rays to partially photopolymerize. A mixture (viscosity 15 poise) was obtained.

  To 100 parts of this partially polymerized monomer mixture, 0.2 parts by weight of trimethylolpropane triacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “V # 295”), as a hydrogen abstraction type radical photoinitiator, A photocurable pressure-sensitive adhesive composition was prepared by uniformly mixing 0.1 part by weight of 2,4,6-trimethylbenzophenone (trade name “ESACURE TZT” manufactured by Nippon Sebel Hegner Co., Ltd.).

  This adhesive composition was applied to a three-layer polarizing plate composed of triacetyl cellulose / polyvinyl alcohol / triacetyl cellulose so that the thickness after light irradiation was 25 μm, and a release mold having a thickness of 25 μm was further formed thereon. The treated polyethylene terephthalate film was covered with the release-treated surface on the coating layer side and shielded from oxygen.

From the upper surface side of this sheet, a metal halide lamp (80 mW / cm ² ) was used to irradiate ultraviolet rays having a light illuminance of 70 mW / cm ² (measured with Topcon UVR-T1 having a peak sensitivity maximum wave of 350 nm) for 10 seconds (irradiation in the first step). . Subsequently, using a black light (15 mW / cm ² ), ultraviolet rays having a light illuminance of 6 mW / cm ² were irradiated for 60 seconds (irradiation in the second step). Subsequently, using a metal halide lamp (80 mW / cm ² ), ultraviolet rays having a light illuminance of 70 mW / cm ² were irradiated for a necessary time until the polymerization rate reached 98%, to obtain an optical member with an adhesive layer.

(Example 2)
In Example 1, a pressure-sensitive adhesive layer was obtained by the same operation as Example 1 except that 2-chlorothioxanthone (manufactured by Nippon Sebel Hegner Co., Ltd., trade name “SPEDCURE CTX”) was used as the hydrogen abstraction type radical photoinitiator. An attached optical member was obtained.

(Example 3)
In Example 1, 4- (13-acryloyl-1,4,7,10,13-pentaoxatridecyl) -benzophenone as an acryloylbenzophenone derivative as a hydrogen abstraction type radical photoinitiator, (Daicel Cytec Co., Ltd.) An optical member with an adhesive layer was obtained by the same operation as in Example 1 except that the product name “Ebecryl P36”) was used.

(Comparative Example 1)
In Example 1, the optical member with an adhesive layer was obtained by the same operation as Example 1 except not including a hydrogen abstraction type radical photoinitiator.

(Comparative Example 2)
In Example 1, a polyethylene terephthalate film / photo-curing pressure-sensitive adhesive composition which was applied on a polyester film having a thickness of 25 μm instead of a three-layer laminated polarizing plate and irradiated with light, that is, a release treatment. A layer of polyethylene / terephthalate film is irradiated with light to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer is transferred to a three-layer polarizing plate. An optical member was obtained.

(Comparative Example 3)
In the comparative example 2, the optical member with an adhesive layer was obtained by the same operation as the comparative example 2 except not containing a hydrogen abstraction type radical photoinitiator.

(Comparative Example 4)
In Comparative Example 3, a primer (manufactured by Nippon Shokubai Co., Ltd., trade name “Polyment NK-380”) was applied to a three-layer polarizing plate so that the thickness after drying was 0.3 μm. After drying, an optical member with a pressure-sensitive adhesive layer was obtained by the same operation as in Comparative Example 3 except that the photocurable pressure-sensitive adhesive composition was applied.

  The following items were evaluated for the optical member with the pressure-sensitive adhesive layer obtained in each Example and each Comparative Example.

(Molecular weight)
It is the weight average molecular weight (Mw) of the partial polymer obtained by GPC (gel permeation chromatography). (Apparatus: manufactured by Tosoh Corporation, trade name “HLC-8020”, column: manufactured by Tosoh Corporation, trade name “TSKgel GMH _HR- H (20)”, solvent: tetrahydrofuran, standard substance: polystyrene)

(Throwing property test)
An ITO (indium / Sn oxide) vapor deposition film was bonded to the adhesive surface side of the obtained optical member with an adhesive layer, left in an atmosphere of 60 ° C. × 90% relative humidity for 1 day, and then cut to a width of 25 mm. The 180 ° peel adhesive strength (N / 25 mm, peel rate 300 mm / min) of the pressure-sensitive adhesive layer with respect to the polarizing plate was measured using a universal tensile tester (Minebea Corp., TCM-1kNB). The results are shown in Table 1.

(Durable adhesive strength under high temperature and high humidity)
The obtained optical member with an adhesive layer was cut into a width of 10 mm to prepare a sample. Each sample was affixed to a bakelite plate with a contact area of 10 mm × 20 mm, left at 80 ° C. for 30 minutes, and then the displacement distance (mm) after 1 hour when a load of 500 g was applied was measured. The results are shown in Table 1.
The evaluation results described above are also shown in Table 1 below.

上記表１の結果により、水素引き抜き型ラジカル重合光開始剤を含む光硬化型粘着剤組成物からなる光硬化型粘着剤組成物層を、光学部材の一面に形成して製造した粘着剤層付光学部材（実施例１，２，３）は、水素引き抜き型ラジカル重合光開始剤を用いない直写塗工により得られた粘着剤層付光学部材（比較例１）よりも、投錨力、高温高湿下における耐久接着力ともに向上していることがわかる。また、水素引き抜き型ラジカル重合光開始剤を含む光硬化型粘着剤組成物からなる粘着剤層を転写により光学部材の一面に形成して製造した粘着剤層付光学部材（比較例２）、水素引き抜き型ラジカル重合光開始剤を含まず光硬化型粘着剤組成物を転写塗工により光学部材の一面に形成して製造した粘着剤層付光学部材（比較例３）においては、投錨力、高温高湿下における耐久接着力ともに大きく低下していることがわかる。また、下塗剤を一層設けた転写塗工により得られた粘着剤層付光学部材（比較例４）においては、投錨力をある程度確保することができるものの、高温高湿下における耐久接着力が実施例１〜３に比して低下している結果になった。従って、本発明の粘着剤層付光学部材は、投錨力、高温高湿下における耐久接着力共に、優れていることが確認できた。

With the result of the said Table 1, with the adhesive layer which formed the photocurable adhesive composition layer which consists of a photocurable adhesive composition containing a hydrogen abstraction type radical polymerization photoinitiator on one surface of an optical member The optical member (Examples 1, 2 and 3) has a higher anchoring force and higher temperature than the optical member with an adhesive layer (Comparative Example 1) obtained by direct-coating without using a hydrogen abstraction type radical polymerization photoinitiator. It can be seen that the durability adhesion under high humidity is improved. Also, an optical member with a pressure-sensitive adhesive layer (Comparative Example 2) produced by forming a pressure-sensitive adhesive layer comprising a photocurable pressure-sensitive adhesive composition containing a hydrogen abstraction type radical polymerization photoinitiator on one surface by transfer, hydrogen In the optical member with a pressure-sensitive adhesive layer (Comparative Example 3) produced by forming a photocurable pressure-sensitive adhesive composition on one surface of the optical member by transfer coating without containing a pull-out type radical polymerization photoinitiator, the anchoring force and the high temperature It can be seen that the durability adhesive strength under high humidity is greatly reduced. Moreover, in the optical member with the pressure-sensitive adhesive layer (Comparative Example 4) obtained by transfer coating with a single layer of primer, the anchoring force can be secured to some extent, but the durable adhesive force under high temperature and high humidity has been implemented. The result was lower than in Examples 1-3. Therefore, it was confirmed that the optical member with the pressure-sensitive adhesive layer of the present invention was excellent in both anchoring force and durable adhesive force under high temperature and high humidity.

Example of manufacturing method of optical member with adhesive Other example of manufacturing method of optical member with adhesive

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical member 2 Photocurable adhesive composition 3 Peeling film 4 Light irradiation 5 Heating 6 Adhesive layer 7 Optical member with an adhesive

Claims (10)

  (A) For 100 parts by weight of a monomer mainly composed of 70 to 99 parts by weight of an alkyl (meth) acrylate having 1 to 14 carbon atoms in the alkyl group and 1 to 30 parts by weight of a vinyl monomer having a polar group, (B) A photocurable pressure-sensitive adhesive composition comprising 0.01 to 5 parts by weight of a polyfunctional vinyl monomer and (c) 0.01 to 1 part by weight of a hydrogen abstraction type radical polymerization photoinitiator. A method for producing an optical member with a pressure-sensitive adhesive layer, comprising forming a photocurable pressure-sensitive adhesive composition layer on at least one surface of an optical member, and forming a pressure-sensitive adhesive layer on the optical member by irradiating light.   2. The method for producing an optical member with an adhesive layer according to claim 1, wherein (c) the hydrogen abstraction type radical polymerization photoinitiator is a benzophenone-based or thioxanthone-based radical polymerization photoinitiator.   The method for producing an optical member with an adhesive layer according to claim 1 or 2, wherein the optical member is made of a resin film constituting a retardation plate or a polarizing plate.   (A) a step of partially polymerizing the component (a) to obtain a monomer mixture containing a partial polymer, and (b) 0.01 to 1 part by weight of a polyfunctional vinyl monomer in the monomer mixture And (c) 0.01 to 1 part by weight of a hydrogen abstraction type radical polymerization photoinitiator to prepare a photocurable pressure-sensitive adhesive composition (B) to prepare a photocurable pressure-sensitive adhesive composition. The manufacturing method of the optical member with an adhesive layer in any one of Claims 1-3 characterized by the above-mentioned.   The pressure-sensitive adhesive according to claim 4, wherein in the step (A) of obtaining the monomer mixture containing the partial polymer, the proportion of the partial polymer in the monomer mixture is 10 to 40% by weight. The manufacturing method of an optical member with an agent layer.   In the step (A) of obtaining a monomer mixture containing the partial polymer, a radical polymerization photoinitiator different from the component (c) is added to the component (a), and the single polymer containing the partial polymer is irradiated by light irradiation. A method for producing an optical member with an adhesive layer according to claim 4 or 5, wherein a mixture of monomers is obtained.   The multifunctional vinyl monomer is added so that the insoluble fraction of the pressure-sensitive adhesive layer is 5 to 70% by weight, The optical member with the pressure-sensitive adhesive layer according to any one of claims 1 to 6 Production method.   The optical member with an adhesive layer obtained by the manufacturing method of the optical member with an adhesive layer in any one of Claims 1-7.   The anchoring force between the pressure-sensitive adhesive layer and the optical member of the optical member with the pressure-sensitive adhesive layer is 20 N / 25 mm or more, and the optical member with the pressure-sensitive adhesive layer is attached to the bakelite plate with a contact area of 10 mm × 20 mm. The pressure-sensitive adhesive according to claim 8, wherein a deviation distance (mm) after 1 hour when a load of 500 g is applied after standing at a constant temperature for 30 minutes is 0.2 (mm) or less. Optical member with agent layer. An image display device using at least one optical member with an adhesive layer according to claim 8 or 9.

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