JP4744179B2 - Adhesive composition, adhesive layer and method for producing the same, and adhesive sheets - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition. More specifically, the present invention relates to a pressure-sensitive adhesive composition that can exhibit excellent pressure-sensitive adhesive properties after a crosslinking reaction, particularly excellent in curved surface adhesiveness, and excellent in long-term durability. Moreover, this invention relates to the adhesive layer formed with the said adhesive composition, and its manufacturing method. Furthermore, this invention relates to the adhesive sheet and the optical member with an adhesive which have the said adhesive layer.

  In industries such as electrical / electronics, architecture, and automobiles, adhesive tapes and sheets are often used for bonding various parts as the variety of products increases. In particular, acrylic pressure-sensitive adhesives are often used because they can easily change the weather resistance, transparency, non-coloring property, or adhesive properties.

  On the other hand, external appearances of these electric products, automobiles, architectures, etc. are increasingly adopting curved surfaces with emphasis on their design. When various parts are bonded to such a curved surface structure, a force that causes the various parts to return to the original form works, so that peeling may occur when the adhesive is resistant.

  Furthermore, these adhesives are essential, although the adhesive strength does not change even after long-term storage and the adhesive properties are stable. In addition, it is also required that the pressure-sensitive adhesive not be colored due to long-term use or heat treatment process.

  Various attempts have been made for such applications. For example, an adhesive is disclosed from an amine compound having a plurality of hydroxyl groups and a polyisocyanate compound in an acrylic polymer having no hydroxyl group (see, for example, Patent Document 1). In addition, a pressure-sensitive adhesive composition comprising an acrylic polymer and a xylene resin, a chlorinated compound, a tackifier, and a crosslinking agent is disclosed (for example, see Patent Document 2). Furthermore, an acrylic pressure-sensitive adhesive obtained by copolymerizing a specific cyclic acrylamide is disclosed (for example, see Patent Document 3). Also disclosed is a method in which a photopolymerization initiator and a crosslinking agent such as isocyanate are contained in a mixture of a monomer and a polymer and cast onto a support to perform photopolymerization (see, for example, Patent Document 4). Furthermore, a pressure-sensitive adhesive composed of a polymer, an isocyanate-based crosslinking agent, a compound having an unsaturated double bond, and a photoinitiator, and a pressure-sensitive adhesive sheet crosslinked with an isocyanate-based crosslinking agent is attached to a wafer and unsaturated double bonds are irradiated by ultraviolet irradiation. There is disclosed a method of reacting a compound having a photoinitiator with a photoinitiator to promote cross-linking and reduce adhesive strength (see, for example, Patent Documents 5 and 6).

  Further, an adhesive is transferred and applied to an optical member used in a liquid crystal display device, such as a polarizing plate or a retardation plate, and the optical member is attached to the liquid crystal cell. Such an optical member expands and contracts greatly under conditions of high heat and high humidity, so that it tends to float and peel off, and the pressure-sensitive adhesive is required to have durability corresponding to this.

  For improving durability, generally, a method of crosslinking the pressure-sensitive adhesive is used, but with an isocyanate-based crosslinking agent or the like, crosslinking is not completed after coating and drying, and aging treatment is necessary. Yes. In addition, the processing time of the aging process is required from one day to one week, and if the cutting process of the next process is performed without sufficiently performing the aging process, the adhesive may adhere to the cutting blade. If the cut pieces are overlapped, they may get stuck between the top and bottom. Further, if heating is performed to promote the aging treatment, the dimensional change of the polarizing plate and the retardation plate occurs, and optical distortion tends to occur.

  In addition, when the optical member is attached to the liquid crystal cell, when the dust is bitten by mistake or misalignment occurs, it is preferable that the liquid crystal cell is reused by removing the optical member. For this purpose, it is necessary that the liquid crystal cell can be easily peeled without changing the gap of the liquid crystal cell at the time of peeling or without being in an adhesive state. In addition, the technique of simply improving the adhesion state with emphasis on durability is inferior in such removability.

  However, even if these techniques are used, there is no one that can sufficiently achieve both the long-term durability and the curved surface adhesion described above.

For example, in the above-mentioned Patent Documents 4 to 6 and the like, there has been disclosed a method in which crosslinking by radicals generated by ultraviolet rays and crosslinking by an isocyanate-based crosslinking agent are used together. In Patent Document 4, although the photopolymerization initiator generates radicals, it is used not for the crosslinking reaction but for the polymerization reaction. When used in the application of the present invention, the influence of the monomer remaining at the time of polymerization is used. It is difficult to exhibit long-term durability. In Patent Documents 5 to 6, the crosslinking of the polymer is carried out with an isocyanate-based crosslinking agent, and UV crosslinking is used to reduce the adhesive strength with the bonded wafer. Phenomenon such as inferiority is seen.
JP 2003-238922 A JP-A-10-158619 JP-A-6-172729 JP 2002-241707 A Japanese Examined Patent Publication No. 6-105752 JP 2004-3198110 A

  Therefore, the present invention, in order to cope with the above-mentioned conventional problems, exhibits excellent adhesive properties after the crosslinking treatment, in particular, excellent in curved surface adhesion, and is also non-coloring and durable in long-term storage, heating conditions, and high-temperature treatment. Another object of the present invention is to provide a re-peelable pressure-sensitive adhesive composition.

  Moreover, an object of this invention is to provide the adhesive layer formed with the said adhesive composition, and its manufacturing method. Furthermore, an object of this invention is to provide the adhesive sheet which has the said adhesive layer, and an optical member with an adhesive.

  In order to achieve the above-mentioned object, the present inventors have intensively studied the constitution of the pressure-sensitive adhesive composition. As a result, the (meth) acrylic polymer having a specific monomer composition contains an isocyanate cross-linking agent and a photo-crosslinking agent. By using a specific amount of the agent composition, it exhibits excellent adhesive properties after cross-linking treatment, in particular excellent in curved surface adhesion, and also has excellent non-coloring properties and weather resistance even during long-term storage, heating conditions, and high-temperature treatment. The inventors have found that a peelable pressure-sensitive adhesive composition can be obtained, and have completed the present invention.

That is, the pressure-sensitive adhesive composition of the present invention is
As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ₁ ) COOR ₂ (where R ₁ is hydrogen or a methyl group, and R ₂ is an alkyl group having 2 to 14 carbon atoms). For 100 parts by weight of (meth) acrylic polymer containing 50 to 99.95% by weight of monomer and 0.05 to 5% by weight of hydroxyl group-containing (meth) acrylic monomer,
It is characterized by containing 0.02 to 2 parts by weight of an isocyanate-based crosslinking agent and 0.02 to 2 parts by weight of a photocrosslinking agent.

  According to the present invention, as shown in the results of the examples, by crosslinking a pressure-sensitive adhesive composition comprising a (meth) acrylic polymer having a specific monomer composition, a specific amount of an isocyanate crosslinker and a photocrosslinker, Excellent curved surface adhesion, easy to peel off from the liquid crystal cell when stored in harsh conditions for long periods of time or stored under high temperature and high humidity conditions, excellent durability, and long-term non-coloring properties The pressure-sensitive adhesive sheet has

  Although the details of the reason why the pressure-sensitive adhesive composition exhibits such properties are not clear, the (meth) acrylic polymer is crosslinked with a specific amount of an isocyanate-based crosslinking agent and a photo-crosslinking agent, thereby ) Acrylic polymers have a structure in which both crosslinking by a photocrosslinking agent (photocrosslinking) and crosslinking by an isocyanate crosslinking agent (isocyanate crosslinking) exist. At this time, the above-mentioned characteristics are not sufficiently expressed by photocrosslinking or isocyanate crosslinking alone, and it is presumed that good long-term durability and curved surface adhesion can be arranged side by side as a result of the presence of both cross-linked structures. .

  This is because the main chain cross-linking (photo-crosslinking), which has excellent relaxation properties due to radiation irradiation, and the strong urethane bond (isocyanate cross-linking) with the isocyanate cross-linking agent coexist in a well-balanced manner to relieve sufficient cohesive force and stress on the adhesive. It is presumed to show a possible behavior. Furthermore, for this reason, when the said adhesive composition is used by making an optical member into a support body, it will be estimated that it becomes an optical member with an adhesive excellent in favorable durability, workability, and removability.

  The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer. The (meth) acrylate refers to acrylate and / or methacrylate.

  In addition, the photocrosslinking agent in the present invention refers to a compound that generates radical active species upon irradiation with radiation (particularly ultraviolet irradiation).

  Furthermore, the isocyanate-based crosslinking agent in the present invention is an isocyanate compound having two or more isocyanate groups (including isocyanate-regenerating functional groups in which isocyanate groups are temporarily protected by a blocking agent or quantification) in one molecule. Say.

The (meth) acrylic polymer in the present invention has, as a monomer unit, a general formula CH ₂ ═C (R ₁ ) COOR ₂ (where R ₁ is hydrogen or a methyl group, R ₂ is an alkyl group having 2 to 14 carbon atoms). Is a copolymer having a (meth) acrylic monomer as a main component, and by using such a polymer as a base polymer of the pressure-sensitive adhesive composition, the pressure-sensitive adhesive has a good balance of adhesiveness and durability. A layer can be obtained.

  The pressure-sensitive adhesive composition of the present invention contains 0.02 to 2 parts by weight of an isocyanate crosslinking agent with respect to 100 parts by weight of the (meth) acrylic polymer, but contains 0.05 to 1 part by weight. It is preferable to contain, and it is more preferable to contain 0.06-0.8 weight part.

  Moreover, in the adhesive composition of this invention, although it contains 0.02-2 weight part of photo-crosslinking agents with respect to 100 weight part of said (meth) acrylic-type polymers, it is 0.05-1 weight part. It is preferable to contain, and it is more preferable to contain 0.06-0.8 weight part.

  In the pressure-sensitive adhesive composition of the present invention, the isocyanate-based crosslinking agent is preferably an aliphatic and / or alicyclic isocyanate-based crosslinking agent. In the present invention, since the photocrosslinking agent generates radical active species upon irradiation, when the aromatic isocyanate compound is used, the cured pressure-sensitive adhesive layer may be colored. Is particularly preferable in applications where

  Moreover, in the adhesive composition for optical members of this invention, it is preferable to contain 0.01-1 weight part of silane coupling agents further with respect to 100 weight part of said (meth) acrylic-type polymers, 0.02-0 More preferably, it is contained in an amount of .6 parts by weight, and more preferably 0.05 to 0.3 parts by weight. By adding an appropriate amount of the silane coupling agent, the adhesion to the adherend and the durability can be more reliably improved.

  In addition, the pressure-sensitive adhesive layer of the present invention is characterized in that it is formed by crosslinking the pressure-sensitive adhesive composition described above. According to the pressure-sensitive adhesive layer of the present invention, since the pressure-sensitive adhesive composition exhibiting the above-described effects is crosslinked, it has excellent pressure-sensitive adhesive layer characteristics, particularly curved surface adhesion, durability, and long-term non-coloring properties. It becomes an excellent pressure-sensitive adhesive layer.

  Furthermore, in the said adhesive layer, it is preferable that the gel fraction of the said adhesive layer is 50 to 90 weight%.

  On the other hand, the pressure-sensitive adhesive layer of the present invention includes, for example, a step of forming a layer made of any of the above-mentioned pressure-sensitive adhesive compositions on one or both sides of a support, and irradiation of the layer made of the pressure-sensitive adhesive composition with radiation. It can obtain by using the manufacturing method including the process to process. By using such a production method, it is possible to obtain a pressure-sensitive adhesive layer that is excellent in the above-mentioned pressure-sensitive adhesive layer characteristics, in particular, curved surface adhesiveness, and in durability and long-term non-colorability.

  In the present invention, the radiation irradiation treatment refers to a treatment for decomposing the photocrosslinking agent by irradiation to generate radicals to crosslink the base polymer.

  The radiation used for the radiation irradiation treatment is particularly preferably ultraviolet rays.

  Moreover, in the adhesive layer obtained in the said manufacturing method, it is preferable that the gel fraction of the said adhesive layer is 50 to 90 weight%.

  On the other hand, the pressure-sensitive adhesive sheets of the present invention are characterized in that the pressure-sensitive adhesive layer is formed on one side or both sides of a support. According to the pressure-sensitive adhesive sheets of the present invention, since the pressure-sensitive adhesive layer having the above-described effects is provided, the pressure-sensitive adhesive layer characteristics, particularly curved surface adhesion, are excellent, and durability, workability, removability, and long-term non- The pressure-sensitive adhesive sheets are excellent in colorability.

  In addition, in this invention, sheets mean a planar material and usually include what is called a film or a tape. Moreover, a double-sided adhesive tape (double-sided tape), a double-sided adhesive sheet, etc. may be sufficient.

  Moreover, the optical member with an adhesive of the present invention is characterized in that the above-mentioned adhesive layer is formed on one side or both sides of the optical member. According to the optical member with the pressure-sensitive adhesive of the present invention, since the pressure-sensitive adhesive layer having the above-described effects is provided, it has excellent pressure-sensitive adhesive layer characteristics, particularly curved surface adhesion, durability, workability, removability, and long-term performance. It becomes an optical member with an adhesive excellent in non-coloring property.

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

That is, the pressure-sensitive adhesive composition of the present invention is
As a monomer unit, a (meth) acrylic group represented by the general formula CH ₂ = C (R ₁ ) COOR ₂ (where R ₁ is hydrogen or a methyl group, and R ₂ is an alkyl group having 2 to 14 carbon atoms). For 100 parts by weight of (meth) acrylic polymer containing 50 to 99.95% by weight of monomer and 0.05 to 5% by weight of hydroxyl group-containing (meth) acrylic monomer,
It is characterized by containing 0.02 to 2 parts by weight of an isocyanate-based crosslinking agent and 0.02 to 2 parts by weight of a photocrosslinking agent.

In the present invention, the monomer unit is represented by the general formula CH ₂ ═C (R ₁ ) COOR ₂ (where R ₁ is hydrogen or a methyl group, and R ₂ is an alkyl group having 2 to 14 carbon atoms). A (meth) acrylic polymer containing 50 to 99.95% by weight of a (meth) acrylic monomer and 0.05 to 5% by weight of a hydroxyl group-containing (meth) acrylic monomer is used.

The (meth) acrylic polymer used in the present invention has the general formula CH ₂ ═C (R ₁ ) COOR ₂ (where R ₁ is hydrogen or a methyl group, and R ₂ is an alkyl group having 2 to 14 carbon atoms). The main component is a (meth) acrylic monomer represented by:

In the above general formula, R ₁ is hydrogen or a methyl group. In the above general formula, R ₂ is an alkyl group having 2 to 14 carbon atoms, preferably 4 to 12 carbon atoms, and more preferably 4 to 9 carbon atoms. The alkyl group for R ₂ may be either linear or branched, but is preferably branched because of its low glass transition point.

Specific examples of the (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ₁ ) COOR ₂ include, for example, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl ( (Meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate , 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate , N-dode Le (meth) acrylate, isomyristyl (meth) acrylate, n- tridecyl (meth) acrylate, etc. n- tetradecyl (meth) acrylate. Of these, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and the like are preferably used.

In the present invention, the above-mentioned (meth) acrylic monomer represented by the general formula CH ₂ ═C (R ₁ ) COOR ₂ may be used alone or in combination of two or more. The content as a whole is 50 to 99.95% by weight, preferably 60 to 99% by weight, and preferably 70 to 98% by weight in the whole monomer of the (meth) acrylic polymer. More preferred. If the amount of the (meth) acrylic monomer is too small, the adhesiveness is poor, which is not preferable.

  The total content of the (meth) acrylic polymer used in the present invention is 0.05 to 5% by weight, preferably 0, of the hydroxyl group-containing (meth) acrylic monomer in the whole monomer of the (meth) acrylic polymer. 0.07 to 2% by weight, more preferably 0.1 to 1.5% by weight. If the content of the hydroxyl group-containing (meth) acrylic monomer is less than 0.05% by weight, the long-term durability is lowered. On the other hand, if the hydroxyl group-containing (meth) acrylic monomer exceeds 5% by weight, it is hard. Since curved surface adhesiveness falls, it is not preferable.

  Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. , 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N -Methylol (meth) acrylamide, N-hydroxy (meth) acrylamide, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. And the like.

  The total content of the (meth) acrylic polymer used in the present invention can contain an unsaturated carboxylic acid in the whole monomer of the (meth) acrylic polymer. When an unsaturated carboxylic acid is used, its content is preferably 0.2 to 15% by weight, more preferably 0.5 to 10% by weight, and 1 to 7% by weight. Further preferred. If the content of the unsaturated carboxylic acid is less than 0.5% by weight, the effect of improving the adhesiveness due to the unsaturated carboxylic acid may be inferior, and the durability may be adversely affected. On the other hand, the content of the unsaturated carboxylic acid may be If it exceeds 15% by weight, it becomes hard and the curved surface adhesiveness is lowered, which is not preferable.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Of these, acrylic acid and methacrylic acid are particularly preferably used.

  In the (meth) acrylic polymer of the present invention, as a monomer other than the above-mentioned (meth) acrylic monomer, a polymerizable monomer for adjusting the glass transition point and peelability of the (meth) acrylic polymer is used. It can be used as long as the effects of the invention are not impaired.

  Examples of other polymerizable monomers used in the (meth) acrylic polymer of the present invention include aggregation of sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, and the like. Functional group that acts as a crosslinking base point for improving adhesive strength, such as components that improve strength and heat resistance, acid anhydride group-containing monomers, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, and vinyl ether monomers And a (meth) acrylic monomer having an alkyl group having 1 or 15 carbon atoms can be used as appropriate. These monomer compounds may be used alone or in admixture of two or more.

  Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth). Examples include acryloyloxynaphthalene sulfonic acid.

  Examples of the phosphate group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

  Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

  Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl laurate, vinyl pyrrolidone and the like.

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and styrene derivatives.

  Examples of the acid anhydride group-containing monomer include maleic anhydride and itaconic anhydride.

  Examples of amide group-containing monomers include acrylamide, methacrylamide, diethyl acrylamide, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N-diethyl acrylamide, N, N-diethyl methacryl. Amides, N, N′-methylenebisacrylamide, N, N-dimethylaminomethylacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, N- (meth) acryloylmorpholine and the like. .

  Examples of the amino group-containing monomer include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, (meth) acrylic acid aminoalkyl ester, and the like.

  Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

  Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl ether.

  Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether, and the like.

  Examples of the (meth) acrylic monomer having an alkyl group having 1 or 15 carbon atoms include methyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, and the like.

  In the present invention, other polymerizable monomers may be used alone or in combination of two or more.

  Furthermore, examples of copolymerizable monomers other than the above include silane monomers containing silicon atoms. Examples of the silane monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, and the like.

  The silane monomer may be used alone, or two or more kinds may be mixed and used. However, the total content of the silane monomer is 0.00 with respect to 100 parts by weight of the (meth) acrylic polymer. It is preferable that it is 1-3 weight part, and it is more preferable that it is 0.5-2 weight part. Copolymerization of a silane monomer is preferable for improving durability.

  The (meth) acrylic polymer used in the present invention preferably has a weight average molecular weight of 600,000 or more, more preferably 700,000 to 3,000,000, and even more preferably 800,000 to 2,000,000. When the weight average molecular weight is less than 600,000, the durability is poor, and the adhesive strength may be generated due to the reduced cohesive force of the pressure-sensitive adhesive composition. On the other hand, from the viewpoint of workability, the weight average molecular weight is preferably 3 million or less. The weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated in terms of polystyrene.

  Moreover, for the reason that it is easy to balance the adhesive performance, the glass transition temperature (Tg) of the (meth) acrylic polymer is −10 ° C. or lower (usually −100 ° C. or higher), preferably −20 ° C. or lower. . When the glass transition temperature is higher than 0 ° C., the polymer is difficult to flow and the wetting to the polarizing plate is insufficient, which may cause blistering generated between the polarizing plate and the pressure-sensitive adhesive composition layer of the pressure-sensitive adhesive sheet. is there. In addition, the glass transition temperature (Tg) of a (meth) acrylic-type polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

  For the production of such a (meth) acrylic polymer, a known radical polymerization method such as solution polymerization, bulk polymerization, and emulsion polymerization can be appropriately selected. Further, the (meth) acrylic polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  In solution polymerization, for example, ethyl acetate, toluene or the like is used as a polymerization solvent. As a specific example of solution polymerization, the reaction is carried out under an inert gas stream such as nitrogen, as a polymerization initiator, for example, azobisisobutyronitrile 0.01 to 0.2 parts per 100 parts by weight of the total amount of monomers. Addition of parts by weight is usually performed at about 50 to 70 ° C. for about 8 to 30 hours.

  The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used.

  Examples of the polymerization initiator used in the present invention include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis [2- ( 5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (N, N′-dimethyleneisobutylamidine ), 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057), azo initiators, potassium persulfate, ammonium persulfate Persulfate such as di (2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di- sec-butyl peroxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1, 1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t- Hexylperoxy) peroxide initiators such as cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, peroxides such as a combination of persulfate and sodium bisulfite, a combination of peroxide and sodium ascorbate, Redox initiators combined with reducing agents can be listed , But it is not limited thereto.

  The polymerization initiator may be used alone or in combination of two or more, but the total content is 0.005 to 1 part by weight with respect to 100 parts by weight of the monomer. Is preferably about 0.02 to 0.5 parts by weight.

  In the present invention, a chain transfer agent may be used in the polymerization. By using a chain transfer agent, the molecular weight of the acrylic polymer can be appropriately adjusted.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol.

  These chain transfer agents may be used alone or in admixture of two or more, but the total content is 0.01-0. About 1 part by weight.

  Examples of the emulsifier used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzene sulfonate, ammonium polyoxyethylene alkyl ether sulfate, sodium polyoxyethylene alkyl phenyl ether sulfate, and polyoxy Nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer are listed. These emulsifiers may be used alone or in combination of two or more.

  Furthermore, as reactive emulsifiers, as emulsifiers into which radical polymerizable functional groups such as propenyl groups and allyl ether groups are introduced, specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05 BC-10, BC-20 (Daiichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE10N (Asahi Denka Kogyo Co., Ltd.) and the like. Reactive emulsifiers are preferable because they are incorporated into the polymer chain after polymerization and thus have improved water resistance. The amount of the emulsifier used is more preferably 0.3 to 5 parts by weight and 0.5 to 1 part by weight with respect to 100 parts by weight of the monomer in view of polymerization stability and mechanical stability.

  The pressure-sensitive adhesive composition of the present invention is based on the (meth) acrylic polymer as described above.

  The pressure-sensitive adhesive composition of the present invention is characterized by containing an isocyanate-based crosslinking agent. These crosslinking agents may be used alone or in combination of two or more.

  Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

  More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylene polyphenyl isocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.), tri Methylolpropane / hexamethylene diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene dii Isocyanurate of cyanate (product name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.), polyether polyisocyanate, polyester polyisocyanate, and adducts of these with various polyols, isocyanurate bond, burette bond And polyisocyanates polyfunctionalized with allophanate bonds.

  Among the above-mentioned isocyanate-based crosslinking agents, it is preferable to use aliphatic and / or alicyclic isocyanate-based crosslinking agents, particularly in applications where transparency and non-coloring properties are required. These crosslinking agents may be used alone or in combination of two or more.

  Examples of the aliphatic isocyanate-based crosslinking agent include aliphatic isocyanate compounds. For example, butylene diisocyanate such as butylene-1,2-diisocyanate, butylene-1,3-diisocyanate, butylene-1,4-diisocyanate, hexamethylene-1,2-diisocyanate, hexamethylene-1,3-diisocyanate, hexamethylene -1,4-diisocyanate, hexamethylene-1,5-diisocyanate, hexamethylene diisocyanate such as hexamethylene-1,6-diisocyanate, hexamethylene-2,5-diisocyanate, trimethylolpropane / hexamethylene diisocyanate trimer addition Such as products (made by Nippon Polyurethane Industry Co., Ltd., trade name Coronate HL), isocyanurate of hexamethylene diisocyanate (made by Japan Polyurethane Industry Co., Ltd., trade name Coronate HX) Aneto acids, adducts of various polyols, isocyanurate bond, biuret bond, polyisocyanates obtained by multi-functionalized with such allophanate bond. These compounds may be used alone or in combination of two or more.

  Examples of the alicyclic (alicyclic) isocyanate crosslinking agent include alicyclic isocyanate compounds. For example, isopentone diisocyanate, cyclopentylene-1,2-diisocyanate, cyclopentylene diisocyanate such as cyclopentylene-1,3-diisocyanate, cyclohexylene-1,2-diisocyanate, cyclohexylene-1,3-diisocyanate, cyclohexene Cyclohexylene diisocyanate such as silene-1,4-diisocyanate, norbornene diisocyanate, hydrogenated xylylene diisocyanate, diisocyanates such as 4,4'-dicyclohexylmethane diisocyanate, adducts with various polyols, isocyanurate bond, burette bond And polyisocyanates polyfunctionalized with allophanate bonds. These compounds may be used alone or in combination of two or more.

  The amount of the isocyanate-based crosslinking agent used is appropriately selected depending on the balance with the (meth) acrylic polymer to be crosslinked and further depending on the intended use as the pressure-sensitive adhesive sheet.

  In the pressure-sensitive adhesive composition of the present invention, it is preferable that 0.02 to 2 parts by weight of the isocyanate-based crosslinking agent is contained with respect to 100 parts by weight of the (meth) acrylic polymer, and 0.05 to 1 part by weight is contained. More preferably, it is more preferably 0.08 to 0.8 parts by weight. If it is less than 0.02 parts by weight, the cohesive force may be insufficient and the durability may be inferior. On the other hand, if it exceeds 2 parts by weight, crosslinking may be excessively formed and the adhesion may be inferior.

  The photocrosslinking agent of the present invention can be appropriately used as long as it generates radical active species by irradiation with radiation (particularly ultraviolet irradiation) to advance the crosslinking of the base polymer of the pressure-sensitive adhesive composition.

  Specific examples of the photocrosslinking agent include hydroxy ketones, benzyl dimethyl ketals, amino ketones, acylphosphine oxides, benzophenones, trichloromethyl group-containing triazine derivatives, and the like.

  Specific examples of the trichloromethyl group-containing triazine derivative include 2- (p-methoxyphenyl) -4,6-bis- (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis- ( Trichloromethyl) -s-triazine, 2- (4′-methoxy-1′-naphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (4′-methoxyphenyl) -6-triazine, 2,4-trichloromethyl (4'-methoxynaphthyl) -6-triazine, 2,4-trichloromethyl (piperonyl) -6-triazine, 2,4-trichloromethyl (4'-methoxystyryl) -6-triazine and the like. In addition, since a polyfunctional photocrosslinking agent having a plurality of radical generation points in the molecule such as 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer, crosslinking efficiency is good. preferable.

  It is preferable to use photosensitizers, such as an acetophenone type compound, a phosphine oxide type compound, an imidazole type compound, for example with the said photocrosslinking agent. By using a photosensitizer, it is possible to crosslink efficiently.

  Examples of the acetophenone compound include 4-diethylaminoacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-benzyl-2-dimethylamino-4′-morpholinobutyrophenone, 2-hydroxy-2-methyl-1-phenylpropane-1 -One, 2,2-dimethoxy-1,2-diphenylethane-1-one and the like.

  Examples of phosphine oxide compounds include phenylbis (2,4,6-trimethylbenzoyl) -phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2,4,6-trimethylbenzoylphenylethoxy. Examples include phosphine oxide.

  Examples of the imidazole compound include 2-p-dimethylphenyl-4-phenyl-imidazole, 4,5-bis-p-biphenyl-imidazole, and 2,2′-bis (2-methylphenyl) -4,4 ′. , 5,5'-tetraphenyl-1,2'-biimidazole, 2,2'-bis (2-chlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole, Examples include 2,2'-bis (2,4-dichlorophenyl) -4,4 ', 5,5'-tetraphenyl-1,2'-biimidazole.

  The photocrosslinking agent may be used alone, or two or more kinds may be mixed and used. However, the total content is 100 parts by weight of the (meth) acrylic polymer. It is preferable to contain 0.02 to 2 parts by weight of a crosslinking agent, more preferably 0.05 to 1 part by weight, and even more preferably 0.08 to 0.8 parts by weight. . If the amount is less than 0.02 parts by weight, there is a case where the crosslinking formation due to irradiation becomes insufficient, and a pressure-sensitive adhesive layer with good durability may not be formed. In some cases, the layer becomes hard and the followability to the dimensional change of the polarizing plate is deteriorated. Polyfunctional monomers and oligomers may be used for cross-linking adjustment, but can be used in consideration of adhesiveness.

  In this invention, it is preferable to adjust the addition amount of an isocyanate type crosslinking agent and a photocrosslinking agent so that the gel fraction of the bridge | crosslinked adhesive layer may be 50 to 90 weight%, and 55 to 85 weight% More preferably, the addition amount of the crosslinking agent is adjusted so that the addition amount of the crosslinking agent is adjusted to 60 to 80% by weight. When the gel fraction is less than 50% by weight, the cohesive force is reduced, so durability and curved surface adhesion may be inferior, and when it exceeds 90% by weight, adhesion may be inferior.

The gel fraction of the pressure-sensitive adhesive composition in the present invention means that after the dry weight W ₁ (g) of the pressure-sensitive adhesive layer is immersed in ethyl acetate, the insoluble content of the pressure-sensitive adhesive layer is taken out from the ethyl acetate and dried. The weight W ₂ (g) was measured, and the value calculated as (W ₂ / W ₁ ) × 100 was taken as the gel fraction (% by weight).

More specifically, for example, W ₁ (g) (about 500 mg) was collected from the pressure-sensitive adhesive layer after crosslinking. Next, the pressure-sensitive adhesive layer was immersed in ethyl acetate at about 23 ° C. for 7 days, and then the pressure-sensitive adhesive layer was taken out and dried at 130 ° C. for 2 hours. W ₂ (g) of the obtained pressure-sensitive adhesive layer Was measured. By applying W ₁ and W ₂ to the above formula, the gel fraction (% by weight) was determined.

  In order to adjust the gel fraction to a certain level, the amount of photo-crosslinking agent and isocyanate-based cross-linking agent should be adjusted, and the effect of cross-linking conditions (radiation dose, irradiation time, heat treatment temperature, heat time, etc.) It is necessary to consider sufficiently.

  Moreover, this crosslinking process may be performed at the temperature at the time of the drying process of an adhesive layer, and you may carry out by providing a crosslinking process process separately after a drying process.

  The crosslinking treatment time can be set in consideration of productivity and workability, but is usually about 0.2 to 20 minutes, preferably about 0.5 to 10 minutes.

  A silane coupling agent can be used in the pressure-sensitive adhesive composition of the present invention. When an optical member is used as a support and affixed to a glass adherend such as a liquid crystal panel, it may be effective in considering its adhesiveness, particularly adhesiveness under high temperature and high humidity conditions. As the silane coupling agent, known ones can be appropriately used without particular limitation.

  Specifically, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltri Epoxy group-containing silane coupling agents such as methoxysilane, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3- Amino group-containing silane coupling agents such as dimethylbutylidene) propylamine, (meth) acryl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-isocyanatopropyl Triethoxysilane etc. Such Inshianeto group-containing silane coupling agent. The use of such a silane coupling agent is preferable because the heat and moisture resistance is improved particularly when glass is used for the adherend.

  The silane coupling agent may be used alone or in combination of two or more, but the total content is 100 parts by weight of the (meth) acrylic polymer. It is preferable to contain 0.01 to 1 part by weight of a silane coupling agent, more preferably 0.02 to 0.6 part by weight, and 0.05 to 0.3 part by weight. More preferably. If it is less than 0.01 part by weight, the durability may be inferior, while if it exceeds 1 part by weight, the adhesive force to an optical member such as a liquid crystal cell may increase and the removability may be inferior.

  Furthermore, the pressure-sensitive adhesive composition of the present invention may contain other known additives, such as powders such as colorants and pigments, dyes, surfactants, plasticizers, tackifiers, Use surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, foils, etc. It can be added appropriately depending on the application. Moreover, you may employ | adopt the redox system which added a reducing agent within the controllable range. These additives may be used alone or in admixture of two or more.

  On the other hand, the pressure-sensitive adhesive layer of the present invention is formed by crosslinking the pressure-sensitive adhesive composition as described above. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer comprising the crosslinked pressure-sensitive adhesive composition to a support or the like. is there.

  The method for forming the pressure-sensitive adhesive layer on the support (or separator, etc.) is not particularly limited. For example, the pressure-sensitive adhesive composition is applied to a release-treated separator, and the polymerization solvent is dried and removed to remove the pressure-sensitive adhesive layer. It is produced by a method of transferring the composition to a support, or a method of applying the pressure-sensitive adhesive composition to the support and drying and removing the polymerization solvent to form a pressure-sensitive adhesive layer on the support. In addition, when an adhesive composition is applied on a support (or separator, etc.) to produce an adhesive sheet, it is polymerized in the composition so that it can be uniformly applied on the support (or separator, etc.). One or more solvents (solvents) other than the solvent may be newly added.

  Examples of the support used in the pressure-sensitive adhesive sheets of the present invention include plastic substrates such as polyethylene terephthalate (PET) and polyester film, and porous materials such as paper and nonwoven fabric.

  The plastic substrate is not particularly limited as long as it can be formed into a sheet shape or a film shape. For example, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene Polyolefin films such as propylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyethylene terephthalate, polyethylene naphthalate, poly Polyester film such as butylene terephthalate, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate Such as ball titanate film, and the like. The thickness of the film is usually about 4 to 100 μm, preferably about 4 to 25 μm.

  For plastic substrates, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agents, mold release with silica powder, etc., acid treatment, acid treatment, alkali treatment, primer treatment, Anti-adhesive treatment such as corona treatment, plasma treatment and ultraviolet treatment, coating type, kneading type, vapor deposition type and the like can also be carried out.

  Examples of the solvent used in the present invention include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, isopropanol, water and the like. . These solvents may be used alone or in combination of two or more.

  Moreover, as a formation method of the adhesive layer of this invention, the well-known method used for manufacture of adhesive sheets is used. Specifically, for example, by roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples thereof include an extrusion coating method.

  For example, the process of forming the layer which consists of one of the above-mentioned adhesive compositions in one side or both surfaces of a support body (sheet | seat), and the process of carrying out radiation treatment of the layer which consists of the said adhesive composition By using the production method including the pressure-sensitive adhesive layer of the present invention, the pressure-sensitive adhesive layer of the present invention can be obtained. By using such a production method, it is possible to obtain a pressure-sensitive adhesive layer in which the above-mentioned excellent pressure-sensitive adhesive properties, particularly curved surface adhesiveness, durability, and long-term non-colorability are arranged in a balanced manner.

  Examples of the radiation used for the radiation irradiation include ultraviolet rays and electron beams, among which ultraviolet rays are particularly preferable. When performing the above-mentioned radiation irradiation treatment, there is no need to use an inert gas atmosphere or to cover the coating film with a cover film that blocks oxygen, and the work efficiency is excellent.

  When ultraviolet rays are used as radiation, for example, low pressure mercury lamp, high pressure mercury lamp, ultra high pressure mercury lamp, metal halide lamp, chemical lamp, black light lamp, mercury-xenon lamp, excimer lamp, short arc lamp, helium / cadmium laser Argon laser, excimer laser, sunlight and the like can be used as the light source for light irradiation. Among them, it is preferable to use a low-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, or the like.

  Moreover, although the wavelength of an ultraviolet-ray can be suitably selected according to the grade of required bridge | crosslinking, it is preferable that it is 200-500 nm, it is more preferable that it is 250-480 nm, and it is 300-480 nm. Is more preferable.

Irradiation conditions in the case of using ultraviolet rays can be appropriately determined depending on the type of the polymer and the photocrosslinking agent, but it is usually preferably in the range of 0.2 to 10 J / cm ² , and 0.3 to 7 J / cm more preferably in the range of cm ^2, and more preferably in the range of 0.5~5J / cm ^2.

  Moreover, the irradiation amount of these ultraviolet rays says the total light quantity of UVA (320-390 nm), UVB (280-320 nm), and UVC (250-260 nm) measured with "UV power pack" (made by EIT).

  The temperature at the time of ultraviolet irradiation is not particularly limited, but is preferably 140 ° C. or lower in consideration of the heat resistance of the support.

  The surface of the pressure-sensitive adhesive layer may be subjected to easy attachment treatment such as corona treatment or plasma treatment.

  In the present invention, the pressure-sensitive adhesive layer is prepared so as to have a thickness after drying of 2 to 500 μm, preferably about 5 to 100 μm.

  When the pressure-sensitive adhesive is exposed on such a surface, the pressure-sensitive adhesive layer may be protected with a release-treated sheet (release sheet, separator, release liner) until it is put to practical use.

  Examples of the constituent material of the separator (release sheet, release liner) include plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester films, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foils, and Although suitable thin leaf bodies, such as these laminates, can be mentioned, a plastic film is preferably used in terms of excellent surface smoothness.

  The plastic film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-polymer are used. Examples thereof include a polymer film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm.

  For the separator, if necessary, mold release and antifouling treatment with a silicone type, fluorine type, long chain alkyl type or fatty acid amide type release agent, silica powder, etc., coating type, kneading type, vapor deposition type It is also possible to carry out antistatic treatment such as. In particular, when the surface of the separator is appropriately subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, the peelability from the pressure-sensitive adhesive layer can be further improved.

  In the above production method, the release-treated sheet (release sheet, separator, release liner) can be used as it is as a separator for pressure-sensitive adhesive sheets, and the process can be simplified.

  The pressure-sensitive adhesive sheets of the present invention are formed by forming a pressure-sensitive adhesive layer having the above-described structure on one side or both sides of a support. Since the pressure-sensitive adhesive sheets of the present invention are provided with a pressure-sensitive adhesive layer having the above-described effects, they are excellent in pressure-sensitive adhesive layer characteristics, in particular, curved surface adhesion, durability, and long-term non-coloring properties. .

  The optical member with pressure-sensitive adhesive of the present invention is obtained by forming a pressure-sensitive adhesive layer on one side or both sides of an optical member such as a polarizing plate from the pressure-sensitive adhesive layer formed by the above production method.

  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 polarizers include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films, and two colors such as iodine and dichroic dyes. Examples include polyene-based oriented films such as those obtained by adsorbing volatile substances and uniaxially stretched, polyvinyl alcohol dehydrated products, and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as 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 and the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing. In addition to washing the polyvinyl alcohol film surface with dirt 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, may be performed while dyeing, or may be dyed with iodine after stretching. 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, (meth) acrylic polymers such as polymethyl methacrylate, polystyrene, acrylonitrile / styrene copolymer (AS resin) And styrene-based polymers such as, and polycarbonate-based polymers. 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 thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, and silicone.

  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 the resin composition or the like can be used.

  Although the thickness of a protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin layer property. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

  Moreover, it is preferable that a protective film has as little color as possible. Therefore, Rth = [(nx + ny) / 2−nz] · d (where nx and ny are the main refractive index in the plane of the film, 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 preferable. 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 by 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 through 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 hard coat layer, an antireflection treatment, an antisticking treatment, or a treatment for diffusion or antiglare.

  Hard coat treatment is performed for the purpose of preventing scratches on the polarizing plate surface, and for example, transparently protects the cured film with excellent hardness and sliding properties with an appropriate UV curable resin such as acrylic and 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.

  Anti-glare treatment is applied for the purpose of preventing external light from reflecting on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, roughening by sandblasting or embossing It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a method or a compounding method of transparent fine particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive composed of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle size of 0.5 to 50 μm. Transparent fine particles such as inorganic fine particles and organic fine particles made of a crosslinked or uncrosslinked polymer may be 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 retardation 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 of this is mention | raise | lifted. These can be used alone as the optical member of the present invention, and can be laminated on the polarizing plate for practical use and used in 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). Thus, there is an advantage that it is easy to reduce the thickness of the liquid crystal display device. 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, if 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 side of a transparent protective film matted as necessary. Moreover, the transparent protective film contains fine particles so as to have a surface fine concavo-convex structure and a reflective layer having a fine concavo-convex structure thereon. 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. The transparent protective film containing fine particles also 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 of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film can be formed by, for example, depositing metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the transparent 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 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, etc. prevents the decrease in reflectance due to oxidation, and thus the long-term sustainability of the initial reflectance. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The transflective polarizing plate can be obtained by using a transflective 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 can save the energy of using a light source such as a backlight in a bright atmosphere, and is useful for forming a liquid crystal display device that can be used with a built-in light source 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 the 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 a 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 various copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become oriented products (stretched films) 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 main-chain liquid crystalline polymers include nematic-oriented polyester-based liquid crystalline polymers, discotic polymers, and cholesteric polymers that have a structure in which a mesogenic group is bonded to a spacer portion that imparts flexibility. It is done. 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 can be obtained by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as one obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate or one obtained by obliquely depositing silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation depending on the purpose of use, such as for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer or compensation of viewing angle, etc. In this case, the retardation plate may be laminated to control optical characteristics such as retardation.

  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. What was used as optical members, such as a polarizing plate, has the advantage that it is excellent in quality stability, lamination workability, etc., and can improve manufacturing efficiency, such as a liquid crystal display device.

  The viewing angle compensation film is a film for widening the viewing angle so that an 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 a support in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and contracting the polymer film under the action of the contraction force by heating, or a film obtained by obliquely aligning a liquid crystal polymer. Is 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 viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of 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 be incident to obtain transmitted light in a predetermined polarization state, and light other than the predetermined polarization state is reflected without being transmitted. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer provided on the rear side thereof, and re-incident on the brightness enhancement film, and 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 transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display by supplying polarized light that is difficult to absorb into 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 it depends 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 is reduced accordingly, resulting in a dark image. In the brightness enhancement film, light having a polarization direction that is absorbed by the polarizer is reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflection layer provided on the rear side thereof. Repeatedly re-enter the brightness enhancement film, and the brightness enhancement film transmits only polarized light whose polarization direction is such that the polarization direction of 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 may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized 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. Thus, while maintaining the brightness of the display screen 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., at the same time, the unevenness of the brightness of the display screen is reduced, 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.

  As the brightness enhancement film, for example, a dielectric multilayer thin film or a multilayer laminate of thin film films having different refractive index anisotropy, such as a characteristic that transmits linearly polarized light having a predetermined polarization axis and reflects other light. Such as a cholesteric liquid crystal polymer alignment film or a film substrate whose alignment liquid crystal layer is supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate ones such as those shown 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 incident on the polarizing plate with the polarization axis aligned as it is, 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 a 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 has, for example, a retardation layer that functions as a quarter-wave plate for light-color light with a wavelength of 550 nm and other retardation characteristics. The phase difference layer shown, for example, the phase difference layer which functions as a half-wave plate, etc. can be obtained by the method of superimposing. 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, a cholesteric liquid crystal layer having a structure in which two or three or more layers are overlapped with a combination of those having different reflection wavelengths can be obtained to reflect circularly polarized light in a wide wavelength range such as a visible light region. 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 three or more optical layers like 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. It is excellent in stability and assembly work, and has the advantage of improving the manufacturing process of a liquid crystal display device and the like. For the lamination, an appropriate adhesive means such as a pressure-sensitive 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.

  In addition, in each layer such as an optical member or an adhesive layer of the adhesive optical member of the present invention, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex compound, etc. What gave the ultraviolet absorptivity by systems, such as a system processed with a ultraviolet absorber, etc. may be used.

  The pressure-sensitive adhesive optical member of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an adhesive optical member, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses the optical member by invention, It can apply to the former. As the liquid crystal cell, for example, an arbitrary type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which an adhesive optical member is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the optical member by this invention can be installed in the one side or both sides of a liquid crystal cell. When optical members are provided on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer of appropriate parts such as a diffuser plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffuser plate, and a backlight at an appropriate position. Alternatively, two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative or the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Or a combination of such a light emitting layer and an electron injection layer composed of a perylene derivative, or a combination of these hole injection layer, light emitting layer, and electron injection layer. Are known.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light particularly when the phase difference plate is a quarter wavelength plate and the angle formed by the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

  Hereinafter, examples and the like specifically showing the configuration and effects of the present invention will be described, but the present invention is not limited to these. In addition, the evaluation item in an Example etc. measured as follows.

<Measurement of molecular weight>
The weight average molecular weight of the obtained (meth) acrylic polymer was measured by GPC (gel permeation chromatography).

Analyzing device: manufactured by Tosoh Corporation, HLC-8120GPC
Data processing device: GPC-8020 manufactured by Tosoh Corporation
column:
Sample column;
Made by Tosoh Corporation, G7000H _XL -H + GMH _XL -H + GMH _XL
Column size: 7.8 mmφ x 30 cm each (total 90 cm)
Flow rate: 0.8ml / min
Injection sample concentration: about 0.1% by weight
Injection volume: 100 μl
Column temperature: 40 ° C
Eluent: Tetrahydrofuran Detector: Differential refractometer (RI)
The molecular weight was calculated in terms of polystyrene.

<Measurement of gel fraction>
W ₁ g (about 0.1 g) of the pressure-sensitive adhesive layer prepared in each Example / Comparative Example was taken out and immersed in ethyl acetate at room temperature (about 25 ° C.) for 1 week. Thereafter, the pressure-sensitive adhesive layer (insoluble matter) subjected to the immersion treatment was taken out from ethyl acetate, and the weight W ₂ g after drying at 130 ° C. for 2 hours was measured, and the value calculated as (W ₂ / W ₁ ) × 100 was obtained. The gel fraction (% by weight) was used.

<Measurement of adhesive strength of double-sided adhesive tape>
The prepared double-sided adhesive tape is attached to a polyester film (thickness: 38 μm) to make a backing film, cut to a size of 25 mm in length × 100 mm in width and sanded with sandpaper (# 280) as an adherend, 2 kg on a stainless steel plate The sample was attached by reciprocating 1 roll and stored at 23 ° C. × 50% RH for 20 minutes to obtain a sample for evaluation.

  The adhesive force (N / 25 mm) when the sample for evaluation was peeled off at a peeling speed of 300 mm / minute peeling angle of 180 ° was measured with a universal tensile tester. The measurement was performed in an environment of 23 ° C. × 65% RH.

<Measurement of curved surface adhesion>
After the prepared double-sided adhesive tape is attached to an aluminum plate (10 mm x 90 mm, thickness: 0.5 mm), it is attached to an acrylic cylinder with a diameter of 300 mm, and how much the double-sided adhesive tape can relieve the force of returning the aluminum plate It was measured and evaluated. The evaluation criteria are as follows.
When the distance from the cylinder is less than 1 mm: ○
When the distance from the cylinder is 1 mm or more: ×

<Durability evaluation>
The prepared double-sided adhesive tape was attached to an aluminum plate (10 mm × 90 mm, thickness: 0.5 mm), then attached to an acrylic cylinder with a diameter of 300 mm, stored in an atmosphere of 100 ° C. for 300 hours, and then room temperature (about The sample for evaluation was obtained. The curved surface adhesiveness of the evaluation sample was measured and evaluated. The evaluation criteria are as follows.
When the distance from the cylinder is less than 1 mm: ○
When the distance from the cylinder is 1 mm or more: ×

<Evaluation of coloring>
Three produced pressure-sensitive adhesive layers were stacked to form a pressure-sensitive adhesive layer having a thickness of 150 μm, cut into a size of 50 mm in length × 50 mm in width, and used as a sample for evaluation before heat treatment. Next, heat treatment was performed at 110 ° C. for 100 hours. Then, it returned to room temperature (about 25 degreeC), and was set as the sample for evaluation after heat processing.

  The color difference of the sample for evaluation is measured with an instantaneous multiphotometer (manufactured by Otsuka Electronics Co., Ltd., MCPD3000, standard light source: CIE-D65, viewing angle: 2 °), and the colorability is evaluated using the sample for evaluation before and after the heat treatment. I did. The color difference calculation method and the evaluation criteria for colorability are as follows.

The color difference is a value represented by ΔE ^* ab,
Delta] E ^* ab = _{^{[(L * 2 -L * 1)}} 2 + (a * 2 -a * 1) 2 + (b * 2 -b * 1) 2 ] ^1/2
Calculated by
Here, L ^* , a ^* , and b ^* are values defined in the CIE 1976 color system,
L ^* ₂ , a ^* ₂ , and b ^* ₂ are L ^* , a ^* , and b ^* of the sample for evaluation after heat treatment at 110 ° C. for 100 hours,
L ^* ₁ , a ^* ₁ , and b ^* ₁ are L ^* , a ^* , and b ^* , respectively, of the sample for evaluation before heat treatment at 110 ° C. for 100 hours.

The evaluation criteria for color difference and colorability are as follows.
When the color difference (ΔE ^* ab) is less than 1.5: ○
When the color difference (ΔE ^* ab) is 1.5 to 2.0: Δ
When the color difference (ΔE ^* ab) exceeds 2.0: ×

<Measurement of adhesive strength of optical member>
The produced optical member was cut into a size of 25 mm in length and 100 mm in width, and adhered to a non-alkali glass plate (Corning Corp., 1737, thickness: 1.0 mm) as an adherend by reciprocating 2 kg of rolls at 50 ° C. After autoclaving for 30 minutes under the condition of × 0.25 MPa, the sample was stored at 23 ° C. × 50% RH for 3 hours to obtain an evaluation sample (a).

  The adhesive force (N / 25 mm) when the sample for evaluation (a) was peeled off at a peeling speed of 300 mm / min and a peeling angle of 90 ° was measured with a universal tensile tester. The measurement was performed in an environment of 23 ° C. × 50% RH.

  Further, after the autoclave treatment, the sample was stored at 70 ° C. for 6 hours and then stored at 23 ° C. × 50% RH for 3 hours to obtain a sample (b) for evaluation.

  The adhesive force (N / 25 mm) when the sample for evaluation (b) was peeled off at a peeling speed of 300 mm / min and a peeling angle of 90 ° was measured with a universal tensile tester, and the value was defined as the adhesive strength after heating. . The measurement was performed in an environment of 23 ° C. × 50% RH.

<Evaluation of durability of optical member>
The produced optical member (12-inch size) was attached to an alkali-free glass plate (Corning Corp., 1737, thickness: 0.5 mm), and autoclaved for 30 minutes under the condition of 50 ° C. × 0.5 MPa. Thereafter, the sample was stored at 60 ° C. × 90% RH for 500 hours and then returned to room temperature (25 ° C.) to obtain a sample for evaluation. The state of adhesion to the glass plate after this treatment was confirmed and evaluated according to the following criteria.
When the optical member does not float, peel off, or foam: ○
When the optical member floats, peels off or foams: ×

<Evaluation of workability>
The produced optical member was subjected to a punching process using a press machine without performing an aging process. The state of the cutting blade during the processing was visually evaluated. The evaluation criteria are as follows.
When there is no adhesion / breakage of the adhesive layer: ○
When adhesion / breakage of adhesive layer is observed: ×

<Preparation of (meth) acrylic polymer>
[Acrylic polymer (A)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 80 parts by weight of butyl acrylate, 15 parts by weight of 2-ethylhexyl acrylate, 5 parts by weight of acrylic acid, 0.2-hydroxyethyl acrylate 0.2 After adding 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator and 200 parts by weight of ethyl acetate as a polymerization initiator, introducing nitrogen gas while gently stirring, and replacing with nitrogen for one hour, A polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at 55 ° C. to prepare an acrylic polymer (A) solution. The acrylic polymer (A) had a weight average molecular weight of 1,750,000.

[Acrylic polymer (B)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 70 parts by weight of butyl acrylate, 29.5 parts by weight of 2-ethylhexyl acrylate, 0.5 part by weight of acrylic acid, 6-hydroxyhexyl Charge 0.15 parts by weight of acrylate, 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 200 parts by weight of ethyl acetate. After the substitution, a polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at 55 ° C. to prepare an acrylic polymer (B) solution. The acrylic polymer (B) had a weight average molecular weight of 1,700,000.

[Reference Example 1]
(Preparation of adhesive solution)
To 100 parts by weight of the solid content of the acrylic polymer (A) solution, 0.3 parts by weight of trimethylolpropane adduct of tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate L) as a crosslinking agent, and 2-hydroxy- 0.1 parts by weight of 2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Lamberti, Esacure KIP 150) was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (1). did.

(Production of double-sided adhesive tape)
The acrylic pressure-sensitive adhesive solution (1) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester Co., Ltd., thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 2.3 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness after drying of 50 μm.

Subsequently, the said adhesive layer was transcribe | transferred to both surfaces of the nonwoven fabric (basis weight 14g / m < ² >), and the double-sided adhesive tape which uses a nonwoven fabric as a support body was produced. In addition, the gel fraction of the said adhesive layer was 61 weight%.

[Example 1]
(Preparation of adhesive solution)
With respect to 100 parts by weight of the solid content of the acrylic polymer (A) solution, 0.3 part by weight of trimethylolpropane adduct of isophorone diisocyanate (Mitsui Takeda Chemicals, Takenate D-140N) as a crosslinking agent, and 2- Add 0.08 parts by weight of hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Lamberti, Esacure KIP 150) and mix and stir uniformly to obtain an acrylic adhesive solution (2) Was prepared.

(Production of double-sided adhesive tape)
The acrylic pressure-sensitive adhesive solution (2) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 1.8 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 50 μm after drying.

Subsequently, the said adhesive layer was transcribe | transferred to both surfaces of the nonwoven fabric (basis weight 14g / m < ² >), and the double-sided adhesive tape which uses a nonwoven fabric as a support body was produced. In addition, the gel fraction of the said adhesive layer was 66 weight%.

[Example 2]
(Preparation of adhesive solution)
0.2 parts by weight of isocyanurate ring trimer of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate HX) as a crosslinking agent with respect to 100 parts by weight of the solid content of the acrylic polymer (B) solution, and 2-hydroxy 0.15 part by weight of 2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Lamberti, Esacure KIP 150) was added and mixed and stirred uniformly to prepare an acrylic adhesive solution (3). Prepared.

(Production of double-sided adhesive tape)
The acrylic pressure-sensitive adhesive solution (3) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light quantity: 2.0 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 50 μm after drying.

Subsequently, the said adhesive layer was transcribe | transferred to both surfaces of the nonwoven fabric (basis weight 14g / m < ² >), and the double-sided adhesive tape which uses a nonwoven fabric as a support body was produced. In addition, the gel fraction of the said adhesive layer was 71 weight%.

Example 3
(Preparation of adhesive solution)
0.2 parts by weight of an isocyanurate ring trimer of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate HX) as a crosslinking agent with respect to 100 parts by weight of the solid content of the acrylic polymer (B) solution, and 2,4 -Trichloromethyl- (piperonyl) -6-triazine (manufactured by PANCHIM, triazine PP) (0.2 parts by weight) was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (4).

(Production of double-sided adhesive tape)
The acrylic pressure-sensitive adhesive solution (4) is applied to one side of a polyethylene-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light quantity: 2.0 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 50 μm after drying.

Subsequently, the said adhesive layer was transcribe | transferred to both surfaces of the nonwoven fabric (basis weight 14g / m < ² >), and the double-sided adhesive tape which uses a nonwoven fabric as a support body was produced. In addition, the gel fraction of the said adhesive layer was 68 weight%.

[Comparative Example 1]
(Preparation of adhesive solution)
The use amount of the trimethylolpropane adduct of tolylene diisocyanate was changed to 0.8 parts by weight, and the 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer was used. An acrylic pressure-sensitive adhesive solution (5) was prepared in the same manner as in Reference Example 1 except that was not used.

(Production of double-sided adhesive tape)
The acrylic pressure-sensitive adhesive solution (5) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 2.3 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness after drying of 50 μm.

Subsequently, the said adhesive layer was transcribe | transferred to both surfaces of the nonwoven fabric (basis weight 14g / m < ² >), and the double-sided adhesive tape which uses a nonwoven fabric as a support body was produced. In addition, the gel fraction of the said adhesive layer was 59 weight%.

[Comparative Example 2]
(Preparation of adhesive solution)
The trimethylolpropane adduct of tolylene diisocyanate was not used and the amount of 2-hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer used was changed to 0.15 parts by weight. An acrylic pressure-sensitive adhesive solution (6) was prepared in the same manner as in Reference Example 1 except that it was used.

(Production of double-sided adhesive tape)
The acrylic pressure-sensitive adhesive solution (6) was applied to one side of a polyethylene-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 2.3 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness after drying of 50 μm.

Subsequently, the said adhesive layer was transcribe | transferred to both surfaces of the nonwoven fabric (basis weight 14g / m < ² >), and the double-sided adhesive tape which uses a nonwoven fabric as a support body was produced. In addition, the gel fraction of the said adhesive layer was 61 weight%.

上記方法に従い、作製した両面粘着テープの接着力の測定、ならびに曲面接着性、耐久性、および着色性の評価を行った。得られた結果を表１に示す。

According to the said method, the adhesive force of the produced double-sided adhesive tape was measured, and curved surface adhesiveness, durability, and coloring property were evaluated. The obtained results are shown in Table 1.

  From the results of Table 1 above, it can be seen that when the double-sided pressure-sensitive adhesive tape produced according to the present invention is used (Examples 1 to 3), the curved surface adhesiveness is excellent in any of the Examples. Moreover, it became clear that it has durability after long-term high-temperature and high-humidity treatment, and the adhesive layer is not colored. Further, in Reference Example 1, although the colorability was slightly inferior to that of the Example, the curved surface adhesiveness and durability could be arranged in a balanced manner as compared with the Comparative Example, and it could be used without any problem depending on the intended use.

  On the other hand, when the double-sided pressure-sensitive adhesive tape that does not satisfy the configuration of the present invention is used (Comparative Examples 1 and 2), in any of the comparative examples, durability after high-temperature and high-humidity treatment, colorability and curved surface adhesiveness are achieved. As a result, it was not possible to arrange them in a balanced manner, and it became clear that they were not suitable for pressure-sensitive adhesive sheets for use in the present invention.

Example 4
(Preparation of adhesive solution)
To 100 parts by weight of the solid content of the acrylic polymer (A) solution, 0.3 parts by weight of trimethylolpropane adduct of tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate L) as a crosslinking agent, and 2-hydroxy- 0.1 parts by weight of 2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Lamberti, Esacure KIP 150) and 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Chemical) as a silane coupling agent Kogyo Co., Ltd., KBM403) 0.1 part by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (7).

(Production of optical member)
The acrylic adhesive solution (7) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 2.3 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 20 μm after drying.

  Next, the pressure-sensitive adhesive layer is transferred to one side of a polarizing plate (polyvinyl alcohol film impregnated with iodine, stretched, and a triacetyl cellulose film is bonded to both sides via an adhesive), and optical with pressure-sensitive adhesive is applied. A member was prepared. In addition, the gel fraction of the said adhesive layer was 61 weight%.

Example 5
(Preparation of adhesive solution)
With respect to 100 parts by weight of the solid content of the acrylic polymer (A) solution, 0.3 part by weight of trimethylolpropane adduct of isophorone diisocyanate (Mitsui Takeda Chemicals, Takenate D-140N) as a crosslinking agent, and 2- 0.08 part by weight of hydroxy-2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Lamberti, Esacure KIP 150), and 3-isocyanatopropyltriethoxysilane (Shin-Etsu Chemical) as a silane coupling agent 0.05 parts by weight of KBE-9007) manufactured by Kogyo Co., Ltd. was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (8).

(Production of optical member)
The acrylic pressure-sensitive adhesive solution (8) was applied to one side of a polyethylene-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 1.8 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 20 μm after drying.

  Next, the pressure-sensitive adhesive layer is transferred to one side of a polarizing plate (polyvinyl alcohol film impregnated with iodine, stretched, and a triacetyl cellulose film is bonded to both sides via an adhesive), and optical with pressure-sensitive adhesive is applied. A member was prepared. In addition, the gel fraction of the said adhesive layer was 68 weight%.

Example 6
(Preparation of adhesive solution)
0.2 parts by weight of isocyanurate ring trimer of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate HX) as a crosslinking agent with respect to 100 parts by weight of the solid content of the acrylic polymer (B) solution, and 2-hydroxy 0.15 parts by weight of 2-methyl- [4- (1-methylvinyl) phenyl] propanol oligomer (Lamberti, Esacure KIP 150), and 3-glycidoxypropyltrimethoxysilane (Shin-Etsu) as a silane coupling agent Chemical Industry Co., Ltd., KBM-403) 0.1 part by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (9).

(Production of optical member)
The acrylic pressure-sensitive adhesive solution (9) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light quantity: 2.0 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 50 μm after drying.

  Next, the pressure-sensitive adhesive layer is transferred to one side of a polarizing plate (polyvinyl alcohol film impregnated with iodine, stretched, and a triacetyl cellulose film is bonded to both sides via an adhesive), and optical with pressure-sensitive adhesive is applied. A member was prepared. In addition, the gel fraction of the said adhesive layer was 71 weight%.

[Comparative Example 3]
(Preparation of adhesive solution)
An acrylic pressure-sensitive adhesive solution (10) was prepared in the same manner as in Example 4 except that the 3-glycidoxypropyltrimethoxysilane was not used.

(Preparation of optical member with adhesive)
An optical member with an adhesive was produced in the same manner as in Example 4 except that the acrylic adhesive solution (10) was used instead of the acrylic adhesive solution (7). In addition, the gel fraction of the said adhesive layer was 60 weight%.

[Comparative Example 4]
(Preparation of adhesive solution)
To 100 parts by weight of the solid content of the acrylic polymer (A) solution, 0.8 part by weight of a trimethylolpropane adduct of tolylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., Coronate L) as a crosslinking agent, and a silane coupling agent As an acrylic pressure-sensitive adhesive solution (11), 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM-403) was added and uniformly mixed and stirred.

(Production of optical member)
The acrylic adhesive solution (11) was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (Mitsubishi Chemical Polyester, thickness: 38 μm), heated at 140 ° C. for 3 minutes, Ultraviolet irradiation (irradiation light amount: 1.8 J / cm ² ) was performed with a metal halide lamp to form an adhesive layer having a thickness of 20 μm after drying.

  Next, the pressure-sensitive adhesive layer is transferred to one side of a polarizing plate (polyvinyl alcohol film impregnated with iodine, stretched, and a triacetyl cellulose film is bonded to both sides via an adhesive), and optical with pressure-sensitive adhesive is applied. A member was prepared. In addition, the gel fraction of the said adhesive layer was 59 weight%.

上記方法に従い、作製した粘着剤付光学部材の接着力の測定、耐久性、および加工性の評価を行った。得られた結果を表２に示す。

According to the said method, the adhesive force measurement of the produced optical member with an adhesive, durability, and evaluation of workability were performed. The obtained results are shown in Table 2.

  From the results of Table 2 above, when the optical member with pressure-sensitive adhesive prepared according to the present invention is used (Examples 4 to 6), it is excellent in removability before and after heat treatment in any of the Examples. Recognize. Moreover, it became clear that it has durability after long-term high-temperature and high-humidity treatment and is excellent in workability.

  On the other hand, when using an optical member with an adhesive that does not satisfy the configuration of the present invention (Comparative Examples 3 to 4), in any of the comparative examples, re-peelability before and after the heat treatment, and after the high temperature and high humidity treatment As a result, durability and processability could not be arranged in a balanced manner, and it became clear that the sheet was not suitable for pressure-sensitive adhesive sheets for use of the present invention.

Claims (9)

One general formula _{CH 2 = C (R 1)} COOR 2 ( provided that, _{R 1} is hydrogen or a methyl group, _{R 2} is an alkyl group having 2 to 14 carbon atoms) represented by (meth) acrylic monomer 50 in 99.95% by weight, and with respect to the hydroxyl group-containing (meth) Ru consists of 0.05 to 5 wt% acrylic monomer as a monomer unit (meth) 100 parts by weight of the acrylic polymer,
Isocyanate crosslinking agent 0.02 to 2 parts by weight, and Ri Na contain photocrosslinking agent 0.02 to 2 parts by weight,
The isocyanate crosslinking agent is, aliphatic and / or alicyclic isocyanate crosslinking agent pressure-sensitive adhesive composition according to der characterized Rukoto. The pressure-sensitive adhesive composition according to claim 1, further comprising 0.01 to 1 part by weight of a silane coupling agent with respect to 100 parts by weight of the (meth) acrylic polymer. Pressure-sensitive adhesive layer, characterized in that by crosslinking a pressure-sensitive adhesive composition according to claim 1 or 2. The pressure-sensitive adhesive layer according to claim 3 , wherein the pressure-sensitive adhesive layer has a gel fraction of 50 to 90% by weight. Production of a pressure-sensitive adhesive layer comprising a step of forming a layer made of the pressure-sensitive adhesive composition according to claim 1 or 2 on one side or both sides of a support, and a step of subjecting the layer made of the pressure-sensitive adhesive composition to radiation irradiation treatment. Method. The method for producing a pressure-sensitive adhesive layer according to claim 5 , wherein the pressure-sensitive adhesive layer has a gel fraction of 50 to 90% by weight. The method for producing an adhesive layer according to claim 5 or 6 , wherein the radiation is ultraviolet rays. Adhesive sheet, characterized in that by forming a pressure-sensitive adhesive layer according to one or both sides of a support to claim 3 or 4. An optical member with an adhesive, wherein the adhesive layer according to claim 3 or 4 is formed on one side or both sides of an optical member.