JP4883749B2 - Optical member pressure-sensitive adhesive composition, optical member pressure-sensitive adhesive layer and production method thereof, optical member with pressure-sensitive adhesive, and image display device - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition for optical members. Moreover, this invention relates to the adhesive layer for optical members formed with the said adhesive composition for optical members. Furthermore, the present invention relates to an adhesive optical member having the adhesive layer, and further to an image display device such as a liquid crystal display device, an organic EL display device, and a PDP using the adhesive optical member. Examples of the optical member include a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and those in which these are laminated.

  In recent years, liquid crystal display devices are widely used not only for mobile phones and personal computers but also for television applications, and the amount of materials is increasing every moment. Optical members used in these liquid crystal display devices, such as polarizing plates and retardation plates, are attached to liquid crystal cells using an adhesive. Since the material used for the optical member has a large expansion and contraction under a heating condition or a humidifying condition, it tends to be lifted or peeled off after being attached. For this reason, the pressure-sensitive adhesive for optical members is required to have durability that can cope with heating conditions and humidification conditions.

  The trend of the screen size of the liquid crystal display device is that the 13-inch (diagonal 33 cm) is the mainstream in the case of notebook computers, but the 15-inch (diagonal 38 cm) is the mainstream, and the 17-inch (diagonal 43 cm) is the mainstream. ) Is the mainstream. And the liquid crystal display device for television use can be less than half the thickness of the conventional cathode ray tube television, which is about 60 cm in depth. Widespread use as a home television.

  As the screen size of liquid crystal display devices is increasing, the polarizing plate contracts under heating conditions as described above, and the liquid crystal cell is warped. Disturbing color unevenness and deteriorating the uniformity of the screen has emerged as a new problem. One of the problems is that the thickness of the glass, which was about 1.1 mm in the past, has been reduced to 0.7 mm. One of the problems is the flatness of the liquid crystal cell especially when the screen is enlarged. Sex is very important.

  In order to solve the above-mentioned problem, an optical member pressure-sensitive adhesive that incorporates glass warpage is disclosed (for example, see Patent Document 1). In this publication, the warp is reduced by adjusting the gel fraction of the two-layer adhesive. However, in this case, the pressure-sensitive adhesive must be laminated, the thickness of the glass plate is about 1.1 mm, and the size is as small as 120 mm × 90 mm (diagonal 15 cm), taking into account the recent increase in screen size. It is not compatible with the large screen. Moreover, when two optical members are bonded together via a glass plate and the warpage is evaluated, there is a problem that stress is offset by the way of taking the absorption axis of the polarizing plate, and the characteristics cannot be accurately evaluated.

  The above is the case where the contraction of the polarizing plate applies a stress to the liquid crystal cell. On the other hand, the optical member such as the polarizing plate is stressed to change the characteristics of the optical member, thereby causing color unevenness, white spots, etc. May be adversely affected.

  Various materials have been proposed as pressure-sensitive adhesives used for such optical members. For example, attempts have been made to improve the stress relaxation property of an adhesive by blending a low molecular weight polymer with a high molecular weight polymer (see, for example, Patent Documents 2 to 5).

  For example, a pressure-sensitive adhesive composition in which 20 to 200 parts by weight of a low molecular weight polymer having a weight average molecular weight of 30,000 or less is blended with 100 parts by weight of a high molecular weight polymer having a high functional group ratio is proposed (for example, Patent Document 2). reference). According to such a pressure-sensitive adhesive composition, it is disclosed that a high molecular weight component has a three-dimensional structure that prevents foaming and peeling under high temperature and high humidity, and that internal stress accompanying dimensional change of a polarizing plate can be absorbed by a low molecular weight polymer component. ing.

  A pressure-sensitive adhesive composition in which a low molecular weight polymer having a weight average molecular weight of 500,000 or less is blended with a high molecular weight polymer has been proposed (see, for example, Patent Document 3). According to this pressure-sensitive adhesive composition, it is disclosed that stress concentration is alleviated and white spots and color unevenness of the liquid crystal cell are suppressed, and adhesive residue and cloudiness do not occur in the liquid crystal cell after peeling.

  Further, 1 to 50 parts by weight of a low molecular weight polymer having a weight average molecular weight of 5,000 or more and less than 500,000 is blended with 100 parts by weight of a high molecular weight polymer, and either one of the high molecular weight polymer or the low molecular weight polymer has a nitrogen-containing functional A pressure-sensitive adhesive sheet made of a pressure-sensitive adhesive composition containing a group has been proposed (see, for example, Patent Document 4). According to such a pressure-sensitive adhesive composition, it is disclosed that it has excellent durability with an adherend of a nitrogen-containing functional group, is excellent in durability, and can suppress white spots following the expansion and contraction of a polarizing plate. .

  In addition, a pressure-sensitive adhesive composition in which 5 to 100 parts by weight of an acrylic oligomer having a weight average molecular weight of 1,000 to 10,000 and a bifunctional cross-linking agent is added to 100 parts by weight of a high molecular weight polymer has been proposed. (See Patent Document 5). According to such a pressure-sensitive adhesive composition, it is disclosed that durability and white spots can be suppressed by having excellent stress relaxation properties as well as excellent adhesion to an adherend.

  However, since the high molecular weight polymer as described above uses an acrylic polymer having a high glass transition temperature and is designed to maintain durability, the stress relaxation property is still insufficient. In particular, the recent trend toward larger screens is not taken into consideration, and it has been found that the stress relaxation property of the liquid crystal cell when the screen size is increased is not sufficient.

  On the other hand, the optical member used in the above liquid crystal display device has an adhesive on one side, but such an optical member with an adhesive is usually produced in a roll shape and punched into a predetermined size. Therefore, there is also a demand for workability such that the adhesive does not adhere to the cutting blade and chip or stick out of the cut surface.

  As an adhesive for attaching an optical member, an acrylic adhesive is generally used for advantages such as durability and transparency, and a crosslinking treatment is applied to give an appropriate cohesive force. It is normal. Various crosslinking agents are selected and used as the crosslinking method for such an acrylic pressure-sensitive adhesive, and a review of functional groups of the acrylic polymer and the crosslinking method has been published (see Non-Patent Document 1).

  Specific examples of the crosslinking agent for the adhesive for attaching an optical member include isocyanate compounds, epoxy compounds, aldehyde compounds, amine compounds, metal salts, metal alkoxides, ammonium salts, hydrazine compounds, and the like (for example, Patent Document 6). Glycidyl compounds, isocyanate compounds, aziridine compounds, metal chelates and the like are also known (see, for example, Patent Document 7).

  Moreover, although organic peroxide is illustrated as a crosslinking agent of a rubber adhesive and a silicone adhesive, it is not described as a crosslinking agent of an acrylic adhesive (for example, refer nonpatent literature 2).

  On the other hand, a tape adhesive composition comprising a heat reaction product of an acrylic copolymer and an organic peroxide in the range of 1 to 6% by weight is known as peroxide crosslinking of an acrylic adhesive (for example, , See Patent Document 8).

  Furthermore, the pressure-sensitive adhesive layer having a gel fraction of less than 40% by weight blended with an acrylic pressure-sensitive adhesive and 0.01 to 10 parts by weight of an organic peroxide that does not undergo a crosslinking reaction at 60 to 100 ° C. is transferred to the breathable substrate. In addition, a method is disclosed in which a pressure-sensitive adhesive is softened by heating and impregnated into a base material, and then further crosslinked to obtain a breathable pressure-sensitive adhesive (see, for example, Patent Document 9).

  Moreover, the olefin part is also cross-linked to an acrylic polymer obtained by copolymerization of a monomer having an olefin polymer in the side chain with an acrylate using an organic peroxide having a 10-hour half-life of 110 ° C. or less. Has been disclosed (for example, see Patent Document 10).

However, an example in which the pressure-sensitive adhesive to be bonded to the optical member stabilizes characteristics by crosslinking with a peroxide, has little change with time, and improves productivity has not been known yet.
Japanese Patent Laid-Open No. 7-294731 JP-A-10-279907 JP 2001-109771 A JP 2001-89731 A JP 2001-335767 A JP 2003-49141 A JP-A-8-199131 Japanese Patent Publication No. 35-4876 JP 2000-17237 A JP 2003-13027 A Adhesive Handbook (2nd edition), edited by Adhesive Tape Industry Association, 1995.10.12. Page 147 Adhesive Handbook (2nd edition), edited by Adhesive Tape Industry Association, 1995.10.12. Pages 121 and 159

  The present invention provides durability against long-term severe conditions, relaxation of stress caused by dimensional changes of optical members (polarizing plates, liquid crystal cells (glass), etc.) (warping of liquid crystal cells (glass)), and re-peeling It aims at providing the adhesive composition for optical members excellent in property.

  Moreover, an object of this invention is to provide the adhesive layer for optical members formed with the said adhesive composition for optical members. Furthermore, an object of the present invention is to provide a pressure-sensitive adhesive optical member having the pressure-sensitive adhesive layer, a manufacturing method thereof, and an image display device using the pressure-sensitive adhesive optical member.

  In order to achieve the above-mentioned object, the present inventors have intensively studied the constitution of the pressure-sensitive adhesive composition, and as a result, found that the above-mentioned object can be achieved by using the following pressure-sensitive adhesive composition for optical members. It came to be completed.

That is, the pressure-sensitive adhesive composition for optical members of the present invention is
As a monomer unit,
Radical polymerizable monomer (A1) whose homopolymer has a glass transition temperature of −70 to −55 ° C. and 40 to 95% by weight, and Radical polymerizable monomer (A2) whose homopolymer has a glass transition temperature of −50 to 0 ° C. ) 100 parts by weight of a radically polymerizable monomer (A) comprising 5 to 60% by weight,
0.1 to 3 parts by weight of unsaturated carboxylic acid monomer (B), and
0.01 to 3 parts by weight of a monomer (C) containing a hydroxyl group,
Containing 100 parts by weight of (meth) acrylic polymer having a glass transition temperature of −45 ° C. or less,
It is characterized by containing 0.01 to 5 parts by weight of an isocyanate-based crosslinking agent.

  According to the present invention, as shown in the results of Examples, the above-mentioned (meth) acrylic polymer having a glass transition temperature of −45 ° C. or less and comprising a specific monomer unit composition, and a specific amount of an isocyanate-based crosslinking agent An optical member with a pressure-sensitive adhesive using a pressure-sensitive adhesive composition for an optical member, which has excellent durability even when stored in a severe condition for a long period of time or when stored under high temperature and high humidity conditions, Stress relieving property due to dimensional change such as a polarizing plate, in particular, a large liquid crystal cell is excellent in removability without causing warpage or color unevenness.

  Although the details of the reason why the pressure-sensitive adhesive composition for optical members exhibits such properties are not clear, the (meth) acrylic polymer having the monomer composition is used as a base polymer, and a specific amount of an isocyanate crosslinking agent is blended. As a result, it becomes excellent in durability without impairing stress relaxation properties, and as a result, when a long time such as passing through various processes after pasting the optical member to the liquid crystal cell or in a high temperature and high humidity state Even when stored, especially for large liquid crystal cells, warpage of the liquid crystal cell (glass) is suppressed in addition to durability, and it is presumed that it has excellent removability without causing color unevenness. The

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

  The (meth) acrylic polymer used in the present invention has a radically polymerizable monomer (A1) having a glass transition temperature of -70 to -55 ° C of 40 to 95% by weight and a glass transition temperature of the homopolymer of-. It is a high molecular weight product mainly composed of a radical polymerizable monomer (A2) consisting of 5 to 60% by weight of a radical polymerizable monomer (A2) at 50 to 0 ° C., and more specifically, the radical polymerization as a monomer unit. 100 parts by weight of the functional monomer (A), 0.1 to 3 parts by weight of the unsaturated carboxylic acid monomer (B), and 0.01 to 3 parts by weight of the monomer (C) containing a hydroxyl group. It is a (meth) acrylic polymer having a transition temperature of −45 ° C. or lower. By using such a polymer as the base polymer of the pressure-sensitive adhesive composition for an optical member, it has excellent relaxation properties against stress caused by dimensional change of the optical member such as a polarizing plate, and color unevenness and whiteness of the polarizing plate caused by residual stress. It is possible to obtain an optical member pressure-sensitive adhesive layer in which the occurrence of leakage or the like is suppressed.

  In the pressure-sensitive adhesive composition for an optical member of the present invention, it is preferable to contain 0.01 to 5 parts by weight of an isocyanate-based crosslinking agent with respect to 100 parts by weight of the (meth) acrylic polymer, and 0.015 to 3 weights. More preferably, it is contained in an amount of 0.02 to 1 part by weight. When the content is less than 0.01 parts by weight, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the pressure-sensitive adhesive composition becomes small, and sufficient weather resistance and heat resistance may not be obtained, Moreover, it may cause glue residue. On the other hand, when the content exceeds 5 parts by weight, the crosslinking is excessive, the cohesive strength of the polymer is increased, the fluidity is lowered, the wettability to the adherend is insufficient, and peeling may be caused. .

  In the pressure-sensitive adhesive composition for an optical member of the present invention, the composition preferably contains 0.02 to 2 parts by weight of a peroxide with respect to 100 parts by weight of the (meth) acrylic polymer. More preferably, it is contained in an amount of 0.1 to 0.5 parts by weight. If less than 0.02 parts by weight, the progress of the crosslinking reaction may be inadequate and may be inferior in durability. On the other hand, if it exceeds 2 parts by weight, the crosslinking structure may be excessive and inferior in adhesiveness. Neither is preferred.

  In the pressure-sensitive adhesive composition for an optical member of the present invention, the cross-linking agent is preferably a hexamethylene diisocyanate compound. The hexamethylene diisocyanate compound in the present invention includes hexamethylene diisocyanate and hexamethylene diisocyanate isocyanurate, burette, adduct, and allophanate type compounds. In addition, the isocyanate group of hexamethylene diisocyanate may be an isocyanate regenerating functional group that is temporarily protected with a blocking agent.

  On the other hand, the pressure-sensitive adhesive layer for an optical member of the present invention includes, for example, a step of forming a layer made of the pressure-sensitive adhesive composition for an optical member according to any one of the above on a single-sided or double-sided surface on a release-treated support, It is obtained by using a production method including a step of heat-treating a layer made of the pressure-sensitive adhesive composition for optical members so that the decomposition amount of the peroxide in the pressure-sensitive adhesive composition for optical members is 75% by weight or more. be able to. By using such a production method, it is possible to obtain a pressure-sensitive adhesive layer for an optical member that balances the above-described excellent removability, durability, and stress relaxation properties in a balanced manner.

  Furthermore, in the pressure-sensitive adhesive layer for optical members obtained in the above production method, the gel fraction of the pressure-sensitive adhesive layer for optical members is preferably 45 to 90% by weight.

  Moreover, the pressure-sensitive adhesive layer for optical members of the present invention is characterized by being formed by crosslinking the pressure-sensitive adhesive composition for optical members described above. According to the pressure-sensitive adhesive layer for an optical member of the present invention, since the pressure-sensitive adhesive composition having the above-described effects is crosslinked, the pressure-sensitive adhesive layer is excellent in durability, removability, and stress relaxation properties. Therefore, it is particularly useful as a re-peelable pressure-sensitive adhesive layer for optical members.

  Furthermore, the pressure-sensitive adhesive layer for an optical member of the present invention has a workability (punching workability) without causing the pressure-sensitive adhesive to adhere to the cutting blade and chip or protrude from the cut surface when punching. Is also excellent.

  Moreover, in the said adhesive member layer for optical members, it is preferable that the gel fraction of the said adhesive member layer for optical members is 45 to 90 weight%.

  Furthermore, the optical member with pressure-sensitive adhesive of the present invention is characterized in that the above-mentioned pressure-sensitive adhesive layer for optical members is formed on one side or both sides of the optical member. According to the optical member with an adhesive of the present invention, the optical member with an adhesive having excellent durability, removability, and stress relaxation properties is provided since the adhesive layer having the above-described effects is provided.

  In addition, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP or the like using the above optical member with an adhesive, and even if stored for a long period of time or in a high temperature / high humidity state, Even when the optical display device is peeled off and the image display apparatus is reused, high durability without foaming is exhibited, and the adhesive force is not increased, and the film can be easily peeled off without adversely affecting the apparatus.

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

That is, the pressure-sensitive adhesive composition for optical members of the present invention is
As a monomer unit,
Radical polymerizable monomer (A1) whose homopolymer has a glass transition temperature of −70 to −55 ° C. and 40 to 95% by weight, and Radical polymerizable monomer (A2) whose homopolymer has a glass transition temperature of −50 to 0 ° C. ) 100 parts by weight of a radically polymerizable monomer (A) comprising 5 to 60% by weight,
0.1 to 3 parts by weight of unsaturated carboxylic acid monomer (B), and
0.01 to 3 parts by weight of a monomer (C) containing a hydroxyl group,
Containing 100 parts by weight of (meth) acrylic polymer having a glass transition temperature of −45 ° C. or less,
It is characterized by containing 0.01 to 5 parts by weight of an isocyanate-based crosslinking agent.

  In the (meth) acrylic polymer in the present invention, the homopolymer has a glass transition temperature of −70 to −55 ° C. and 40 to 95% by weight of the radical polymerizable monomer (A1), and the homopolymer has a glass transition temperature of −50. It is a high molecular weight body mainly comprising a radical polymerizable monomer (A) consisting of 5 to 60% by weight of a radical polymerizable monomer (A2) at ˜0 ° C., and more specifically, as the monomer unit, the radical polymerizable monomer Glass transition comprising 100 parts by weight of monomer (A), 0.1 to 3 parts by weight of unsaturated carboxylic acid monomer (B), and 0.01 to 3 parts by weight of monomer (C) containing a hydroxyl group A (meth) acrylic polymer having a temperature of −45 ° C. or lower.

  In the radically polymerizable monomer (A) of the present invention, the homopolymer has a glass transition temperature of −70 to −55 ° C., the radical polymerizable monomer (A1) of 40 to 95% by weight, and the homopolymer has a glass transition temperature of − It consists of 5 to 60% by weight of the radically polymerizable monomer (A2) that is 50 to 0 ° C., and 50 to 95% by weight of the radically polymerizable monomer (A1) and the glass transition temperature of the homopolymer is −50 to 0 ° C. The radical polymerizable monomer (A2) is preferably composed of 5 to 50% by weight.

  As the radical polymerizable monomer (A1), a radical polymerizable monomer whose homopolymer has a glass transition temperature of −70 to −55 ° C. is used. Examples of such a monomer include heptyl acrylate, isononyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, and the like. These monomers may be used alone or in combination of two or more.

  As the radical polymerizable monomer (A2), a radical polymerizable monomer having a glass transition temperature of -50 to 0 ° C. is used. Examples of such a monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and isoamyl hexyl acrylate. These monomers may be used alone or in combination of two or more.

  In addition, the glass transition temperature of each homopolymer in this invention and the glass transition temperature of a copolymer were measured using the DSC (differential scanning calorie | heat amount) analyzer. In the temperature raising process, the temperature at which heat absorption starts is defined as the glass transition temperature (Tg).

  In the above (meth) acrylic polymer, the unsaturated carboxylic acid monomer (B) in the present invention is contained as a monomer unit in an amount of 0.1 to 3 parts by weight with respect to 100 parts by weight of the radical polymerizable monomer. 0.2 to 3 parts by weight is preferable, and 0.3 to 2.5 parts by weight is more preferable. When the content exceeds 3% by weight, the adhesive force to the liquid crystal cell may be excessively increased. On the other hand, when the content is less than 0.1% by weight, the durability may be adversely affected.

  Examples of the unsaturated carboxylic acid monomer (B) 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. These monomers may be used alone or in combination of two or more.

  Furthermore, as the unsaturated carboxylic acid monomer (B), for example, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride may be appropriately used.

  The monomer (C) containing a hydroxyl group in the present invention is contained in an amount of 0.01 to 3 parts by weight as a monomer unit in 100 parts by weight of the radical polymerizable monomer in the (meth) acrylic polymer. 0.05 to 2 parts by weight is preferable, and 0.1 to 2 parts by weight is more preferable. If the content exceeds 3% by weight, the crosslinking density with the isocyanate cross-linking agent may increase, and the stress relaxation may be inferior. On the other hand, if the content is less than 0.01% by weight, the reaction with the isocyanate cross-linking agent may occur. May be detrimental and adversely affect durability.

  The monomer (C) containing a hydroxyl group refers to one represented by the following general formula (I).

  (In the formula (I), R is an alkyl group having 2 to 6 carbon atoms and containing at least one hydroxyl group.)

  More specifically, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 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, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether, etc. That. These monomers may be used alone or in combination of two or more.

  Other polymerizable monomers other than the above-mentioned radical polymerizable monomer (A), unsaturated carboxylic acid monomer (B), and monomer (C) containing a hydroxyl group are the glass transition point and peelability of the (meth) acrylic polymer. A polymerizable monomer or the like for adjusting the viscosity can be used as long as the effects of the present 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. It has a functional group that acts as a crosslinking point and improves adhesive strength such as components that improve strength and heat resistance, amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine, and vinyl ether monomers. Ingredients 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, (meth And acryloyloxynaphthalene sulfonic acid.

  Examples of the phosphoric acid group-containing monomer include 2-hydroxyethylacryloyl 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, chloromethyl styrene, α-methyl styrene, and the like.

  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. Examples thereof include amide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide and the like.

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

  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.

  In the present invention, other polymerizable monomers may be used alone or in admixture of two or more, but the total content is 100 parts by weight of the radical polymerizable monomer (A). Is preferably 0 to 10 parts by weight, and more preferably 0 to 5 parts by weight.

  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 desirably has a weight average molecular weight of 1,000,000 or more, preferably 1,200,000 or more, more preferably 1,500,000 or more. When the weight average molecular weight is less than 1,000,000, the durability tends to be poor, and the adhesive force tends to occur 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. In addition, a weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  In addition, because the adhesive performance is easily balanced, the glass transition temperature (Tg) of the (meth) acrylic polymer is −45 ° C. or lower (usually −100 ° C. or higher), preferably −48 ° C. or lower, more preferably − It is desirable that it is 50 degrees C or less. When the glass transition temperature is higher than −45 ° C., particularly when the screen is enlarged, stress relaxation due to dimensional change of the optical member (polarizing plate, liquid crystal cell (glass), etc.) (liquid crystal cell (glass) (Warp) may be insufficient. 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, Examples include redox initiators combined with reducing agents. The present invention is not limited to.

  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 0.6 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.

  In addition, as an emulsifier used when an acrylic polymer is produced by an emulsion polymerization method, for example, sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, polyoxyethylene alkyl ether ammonium sulfate, polyoxyethylene alkyl phenyl ether sodium sulfate And nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, polyoxyethylene-polyoxypropylene block polymer, and the like. 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 for optical members of the present invention is based on the (meth) acrylic polymer as described above.

  In the pressure-sensitive adhesive composition for optical members of the present invention, an isocyanate-based crosslinking agent is used. Further, the isocyanate-based crosslinking agent refers to an isocyanate compound having two or more isocyanate groups (including isocyanate-regenerating functional groups in which the isocyanate group is temporarily protected by blocking agent or quantification) in one molecule.

  Examples of the isocyanate compound 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, examples of the isocyanate compound include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, Aromatic diisocyanates such as 4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), tri Methylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Coronate HL), hexamethylene diisocyanate Over the door of the isocyanurate body (Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HX), and the like, such as isocyanate adducts such as. Furthermore, adducts of various polyols of these isocyanate compounds can be mentioned. These isocyanate compounds may be used alone or in combination of two or more.

  Among these, the crosslinking agent is preferably an aliphatic isocyanate compound, particularly a hexamethylene diisocyanate compound, particularly from the viewpoint of non-yellowing and stress relaxation. In addition, aliphatic isocyanate compounds are highly reactive with carboxyl groups and hydroxyl groups, can be crosslinked even in small amounts, and have high crosslinking efficiency.

  Hexamethylene diisocyanate compounds are meant to include, for example, hexamethylene diisocyanate and other types of compounds such as isocyanurates, burettes, adducts, and allophanates of hexamethylene diisocyanate. In addition, the isocyanate group of hexamethylene diisocyanate may be an isocyanate regenerating functional group that is temporarily protected with a blocking agent. Furthermore, in order to increase the anchoring force with respect to the optical member, an isocyanate compound that suppresses the reactivity with the polymer, such as an adduct body of diisocyanate trimethylolpropane, can be used in combination.

  Further, from the viewpoint of weather resistance, isocyanurate type compounds are more preferable. From the viewpoint of adhesion to optical members, burette type compounds are more preferable, and these may be used in combination.

  The amount of the isocyanate-based crosslinking agent used is preferably 0.01 to 5 parts by weight of the isocyanate-based crosslinking agent, based on 100 parts by weight of the (meth) acrylic polymer, and 0.03 to 3 parts by weight. It is more preferable to contain, and it is still more preferable to contain 0.05-1 weight part. When the content is less than 0.01 parts by weight, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive force of the pressure-sensitive adhesive composition becomes small, and sufficient weather resistance and heat resistance may not be obtained, Moreover, it may cause glue residue. On the other hand, when the content exceeds 5 parts by weight, the crosslinking is excessive, the cohesive strength of the polymer is increased, the fluidity is lowered, the wettability to the adherend is insufficient, and peeling may be caused. .

  Further, when an aliphatic isocyanate compound is used in order to improve non-yellowing and stress relaxation properties, the amount of the isocyanate crosslinking agent used is 50% by weight or more, preferably 60% by weight or more, more preferably 65% by weight or more. It is preferable to use it.

  The peroxide of the present invention can be used as appropriate as long as it generates radical active species by heating and allows the crosslinking of the base polymer of the pressure-sensitive adhesive composition to proceed, but taking into consideration workability and stability. It is preferable to use a peroxide having a one-minute half-life temperature of 80 ° C. to 160 ° C., and more preferable to use a peroxide having a 90 ° C. to 140 ° C. If the half-life temperature for 1 minute is too low, the reaction proceeds at the time of storage before coating and drying, and the viscosity may become high and the coating may become impossible. On the other hand, if the half-life temperature is too high, Since the temperature becomes high, side reactions occur, and a large amount of unreacted peroxide remains, which may cause cross-linking over time.

  Examples of the peroxide used in the present invention include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.), di (4-t-butylcyclohexyl) peroxydicarbonate ( 1 minute half-life temperature: 92.1 ° C.), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C.), t-butyl peroxyneodecanoate (1 minute half-life temperature: 103.5 ° C.), t-hexyl peroxypivalate (half-life temperature for 1 minute: 109.1 ° C.), t-butyl peroxypivalate (half-life temperature for 1 minute: 110.3 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116.4 ° C.), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C.), 1,1,3,3-tetramethylbutyl Oxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C), dibenzoyl peroxide (half-minute for 1 minute) Period temperature: 130.0 ° C.), t-butyl peroxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.). Especially, since the crosslinking reaction efficiency is excellent, di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.), dilauroyl peroxide (1 minute half-life temperature: 116. 4 ° C), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C) and the like are preferably used.

  The peroxide may be used alone, or two or more kinds may be mixed and used, but the total content is 0.1% relative to 100 parts by weight of the (meth) acrylic polymer. It is preferably 02 to 2 parts by weight, more preferably 0.05 to 1 part by weight, and even more preferably 0.08 to 0.6 parts by weight. If less than 0.02 parts by weight, the progress of the crosslinking reaction may be inadequate and may be inferior in durability. On the other hand, if it exceeds 2 parts by weight, the crosslinking structure may be excessive and inferior in adhesiveness. Neither is preferred.

  In addition, when a peroxide is used as a polymerization initiator, it is possible to use the remaining peroxide for the crosslinking reaction without being used in the polymerization reaction. If necessary, it can be added again and used in a predetermined amount of peroxide.

  The peroxide half-life is an index representing the decomposition rate of the peroxide, and means the time until the remaining amount of peroxide is reduced to half. The decomposition temperature for obtaining a half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer catalog, for example, “Organic peroxide catalog 9th edition by Nippon Oil & Fats Co., Ltd.” (May 2003) ".

  In addition, as a measuring method of the peroxide decomposition amount which remained after the reaction process, it can measure by HPLC (high performance liquid chromatography), for example.

  More specifically, for example, about 0.2 g of the pressure-sensitive adhesive composition after the reaction treatment is taken out, immersed in 10 ml of ethyl acetate, extracted by shaking at 25 ° C. and 120 rpm for 3 hours with a shaker, and then at room temperature. Leave for 3 days. Next, 10 ml of acetonitrile was added, shaken at 120 rpm at 25 ° C. for 30 minutes, and about 10 μl of the extract obtained by filtration through a membrane filter (0.45 μm) was injected into the HPLC for analysis. The amount of peroxide can be set.

  In this invention, it is preferable to adjust the addition amount of a crosslinking agent so that the gel fraction of the bridge | crosslinked adhesive layer may be 45 to 90 weight%, and it is 47 to 85 weight% of a crosslinking agent so that it may become 47 to 85 weight%. It is more preferable to adjust the addition amount, and it is more preferable to adjust the addition amount of the crosslinking agent so as to be 50 to 80 wt%. When the gel fraction is less than 45% by weight, the durability tends to be inferior, and when it exceeds 90% by weight, the stress relaxation property tends to be inferior.

In the present invention, the gel fraction means that the dry weight W ₁ (g) of the pressure-sensitive adhesive layer is wrapped in a microporous tetrafluoroethylene film (the weight of the film is W ₂ (g)) and then immersed in ethyl acetate. The agent layer is taken out from ethyl acetate, the weight W ₃ (g) after drying is measured, and the value is calculated by the following formula.

Gel fraction (% by weight) = [(W ₃ −W ₂ ) / W ₁ ] × 100 (% by weight)

More specifically, W ₁ (g) (about 0.1 g) was collected from the pressure-sensitive adhesive layer after crosslinking. Next, the pressure-sensitive adhesive layer is wrapped in a microporous tetrafluoroethylene film (the weight of the film is W ₂ (g)), and the pressure-sensitive adhesive layer is immersed in ethyl acetate (about 50 ml) at about 23 ° C. for 2 days. The soluble component was extracted. Then removed the pressure-sensitive adhesive layer, and dried for 2 hours at 130 ° C., the weight W ₃ of the obtained adhesive layer and the film _(g) was measured. The gel fraction (% by weight) was determined by applying W _{1 to} W ₃ to the above formula. After coating, the gel fraction was measured after storage for 7 days at room temperature (approximately 23 ° C.).

  In order to adjust to a predetermined gel fraction, it is necessary to fully consider the influence of the crosslinking treatment temperature and the crosslinking treatment time as well as adjusting the addition amount of the peroxide and the crosslinking agent.

  The adjustment of the crosslinking treatment temperature and the crosslinking treatment time is, for example, preferably set so that the decomposition amount of the peroxide contained in the optical member pressure-sensitive adhesive composition is 75% by weight or more, and 80% by weight or more. More preferably, the setting is more preferably 85% by weight or more. When the amount of peroxide decomposition is less than 75% by weight, the amount of peroxide remaining in the pressure-sensitive adhesive composition for optical members increases, and as a result, a crosslinking reaction over time occurs even after the crosslinking treatment. In some cases, the gel fraction exceeds 90% by weight, which is not preferable.

  More specifically, for example, at a crosslinking treatment temperature of 1 minute half-life temperature, the decomposition amount of peroxide is 50% by weight in 1 minute, and the decomposition amount of peroxide is 75% by weight in 2 minutes. A crosslinking treatment time of 2 minutes or more is required. For example, if the half-life of the peroxide at the crosslinking treatment temperature (half-life) is 30 seconds, a crosslinking treatment time of 1 minute or more is required. For example, the half-life of the peroxide at the crosslinking treatment temperature If the (half time) is 5 minutes, a crosslinking treatment time of 10 minutes or more is required.

  Thus, the crosslinking treatment temperature and crosslinking treatment time can be calculated by theoretical calculation from the half-life (half-life time) assuming that the peroxide is linearly proportional to the peroxide used. It can be adjusted as appropriate. On the other hand, the higher the temperature, the higher the possibility of side reactions, so the crosslinking treatment temperature is preferably 170 ° C. or lower.

  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.

  In the pressure-sensitive adhesive composition for an optical member of the present invention, a silane coupling agent may be appropriately added as an optional component. As such a silane coupling agent, known ones can be appropriately used without particular limitation.

  For example, epoxy such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane Group-containing silane coupling agent, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propyl Amino group-containing silane coupling agents such as amines, (meth) acryl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane, and 3-isocyanatopropyltriethoxysilane Insiane Such as preparative group-containing silane coupling agent. Use of such a silane coupling agent is preferable for improving durability.

  The silane coupling agent may be used alone or in combination of two or more, but the total content is based on 100 parts by weight of the monomer mixture of the (meth) acrylic polymer. The content is preferably 0.01 to 1 part by weight, more preferably 0.02 to 0.6 part by weight, and still more preferably 0.05 to 0.3 part by weight. When the amount is less than 0.01 part by weight, it is difficult to improve the durability. On the other hand, when the amount exceeds 1 part by weight, the adhesion to the liquid crystal cell tends to increase and the removability is poor.

  Furthermore, the pressure-sensitive adhesive composition for optical members of the present invention may contain other known additives, such as powders such as colorants and pigments, dyes, surfactants, plasticizers, and adhesive properties. Giving agents, surface lubricants, leveling agents, softeners, antioxidants, anti-aging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, foils, etc. Can be added as appropriate according to the intended use.

  On the other hand, the pressure-sensitive adhesive layer for optical members of the present invention is formed by crosslinking the pressure-sensitive adhesive composition for optical members as described above. At that time, the pressure-sensitive adhesive composition for optical members is generally crosslinked after the application of the pressure-sensitive adhesive composition for optical members, but the pressure-sensitive adhesive for optical members comprising the pressure-sensitive adhesive composition for optical members after crosslinking. It is also possible to transfer the layer to an optical member or the like.

  The method for forming the pressure-sensitive adhesive layer for the optical member on the optical member (or separator, support film, 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. It is prepared by a method of removing and forming a pressure-sensitive adhesive layer on an optical member, or a method of applying the pressure-sensitive adhesive composition on an optical member and drying and removing a polymerization solvent to form a pressure-sensitive adhesive layer on the optical member. The Thereafter, curing (aging treatment) may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. In addition, when the pressure-sensitive adhesive composition is coated on an optical member (or separator, support film, etc.) to produce pressure-sensitive adhesive sheets, it can be uniformly coated on the optical member (or separator, support film, etc.) One or more solvents (solvents) other than the polymerization solvent may be newly added to the composition.

  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 for optical members of this invention, the well-known method used for manufacture of adhesive sheets is used. Specifically, for example, methods such as roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, extrusion coat method using a die coater, etc. Is given.

  Further, for example, a step of forming a layer made of the pressure-sensitive adhesive composition for an optical member described above on one side or both sides on a release-treated support (a release-treated sheet), and the pressure-sensitive adhesive for the optical member The optical member of the present invention can be obtained by using a manufacturing method including a step of heat-treating a layer made of the pressure-sensitive adhesive composition for optical members so that the decomposition amount of peroxide in the composition is 75% by weight or more. A pressure-sensitive adhesive layer can be obtained. By using such a production method, it is possible to obtain a pressure-sensitive adhesive layer for an optical member that balances the above-described excellent removability, durability, and stress relaxation properties in a balanced manner.

  In addition, in this invention, it produces so that the thickness after drying of the said adhesive layer for optical members may be set to 2-500 micrometers, Preferably it is about 5-100 micrometers.

  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 Suitable thin leaf bodies such as these laminates can be mentioned, and a plastic film is preferably used from the viewpoint of excellent surface smoothness.

  The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer. Examples thereof include a coalesced 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 an optical member with an adhesive, and the process can be simplified.

  Moreover, the optical member with an adhesive of this invention forms the adhesive layer for optical members which has said structure on the single side | surface or both surfaces of an optical member.

  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, examples of the optical member include a polarizing plate. As the polarizing plate, one having a transparent protective film on one side 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, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film can also be formed as a cured layer of 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 in the 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 applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. with an appropriate ultraviolet curable resin such as acrylic or silicone It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  Anti-glare treatment is applied for the purpose of preventing the external light from being reflected on the surface of the polarizing plate and obstructing the visibility of the light transmitted through the polarizing plate. For example, the surface is roughened by 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 blending 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.

  In addition, examples of the optical member of the present invention include 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 the formation of is mentioned. 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. Moreover, 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.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. 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 according to the purpose of use, such as for the purpose of compensating for coloring or viewing angle due to birefringence of various wavelength plates and liquid crystal layers, for example. 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 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 (reflection type) polarizing plate and a retardation plate. An optical member such as an elliptically polarizing plate is advantageous in that it is excellent in quality stability, laminating workability, etc., and can improve the manufacturing efficiency of a liquid crystal display device or the like.

  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 tilted alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, or a film obtained by obliquely aligning a liquid crystal polymer. Can be given. 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 enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected from the surface of the brightness enhancement film is further inverted through a reflective layer provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. The brightness can be improved by increasing the amount of light transmitted through the improvement 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. is there. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and accordingly, the amount of light that can be used for liquid crystal image display is reduced, 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 directly incident on a polarizer, but from the point of suppressing absorption loss, the circularly polarized light is converted into linearly polarized light through a retardation plate. It is preferably incident on the 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 that has a reflection wavelength different from each other and has an arrangement structure in which two layers or three or more layers are overlapped to obtain a layer that reflects 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. There is an advantage that the manufacturing process of the liquid crystal display device and the like can be improved because of excellent stability and assembly work. 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, each layer such as an optical member or an adhesive layer of the adhesive optical member of the present invention includes, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, a nickel complex compound, and the like. 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.

  In order to improve the anchoring force when such an optical member is bonded to the above-mentioned pressure-sensitive adhesive layer, the surface of the optical member may be subjected to easy attachment treatment such as corona treatment or plasma treatment, or undercoating treatment.

  The optical member with pressure-sensitive adhesive of the present invention is characterized by having the above-described configuration, and has a pressure-sensitive adhesive layer that exhibits the above-described effects, so that the pressure-sensitive adhesive has excellent durability, removability, and stress relaxation properties. It becomes an attached optical member.

  In addition, the image display device of the present invention is a liquid crystal display device, an organic EL display device, a PDP or the like using the above optical member with an adhesive, and even if stored for a long period of time or in a high temperature / high humidity state, Even when the optical display device is peeled off and the image display apparatus is reused, high durability without foaming is exhibited, and the adhesive force is not increased, and the film can be easily peeled off without adversely affecting the apparatus.

  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 molecular weight 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;
(Meth) acrylic polymers;
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 glass transition temperature (Tg)>
The glass transition temperature (Tg) was measured with a DSC (Differential Scanning Calorimetry) analyzer.

Analyzer: Seiko Electronics Co., Ltd., DSC6200
Sample weight: 7-13mg
Temperature increase rate: 10 ° C / min
Nitrogen flow rate: 60-70 ml / min
Cooling method: Use liquid nitrogen

  Moreover, the actual measurement result of the glass transition temperature (Tg) of each homopolymer is shown below.

Tg of 2-ethylhexyl acrylate homopolymer: -64 ° C
Tg of homopolymer of n-butyl acrylate: -46 ° C
Tg of homopolymer of isooctyl acrylate: -62 ° C
None of them contains carboxylic acid as a monomer unit.

<Measurement of gel fraction>
W ₁ (g) (about 0.1 g) was collected from the crosslinked pressure-sensitive adhesive layer prepared in each Example / Comparative Example, and then the pressure-sensitive adhesive layer was wrapped in a microporous tetrafluoroethylene film (weight of the film). W ₂ (g)), and the pressure-sensitive adhesive layer was immersed in ethyl acetate (about 50 ml) at about 23 ° C. for 2 days to extract soluble components. Then removed the pressure-sensitive adhesive layer, and dried for 2 hours at 130 ° C., the weight W ₃ of the obtained adhesive layer and the film _(g) was measured. The gel fraction (% by weight) was determined by applying W _{1 to} W ₃ to the following formula.

Gel fraction (% by weight) = [(W ₃ −W ₂ ) / W ₁ ] × 100 (% by weight)
After coating, the gel fraction was measured after storage for 7 days at room temperature (approximately 23 ° C.).

<Evaluation of durability (humidification test)>
The produced optical member was cut into a size of 24 cm in length and 32 cm in width (15-inch size) and pasted on an alkali-free glass plate (Corning Corp., 1737, size: 25 × 35 cm, thickness: 0.7 mm), Autoclaving was performed at 50 ° C. and a pressure of 0.5 MPa for 15 minutes. Thereafter, the sample was stored for 500 hours in an atmosphere of 60 ° C. × 90% RH and then returned to room temperature (about 25 ° C.) to obtain a sample for evaluation.

  The adhesion state of the sample for evaluation to the glass plate was visually observed and evaluated. The evaluation criteria are as follows.

The optical member did not float or peel off. : ○
The optical member was lifted or peeled off. : ×

<Evaluation of durability (heat resistance test)>
The produced optical member was cut into a size of 24 cm in length and 32 cm in width (15-inch size) and pasted on an alkali-free glass plate (Corning Corp., 1737, size: 25 × 35 cm, thickness: 0.7 mm), Autoclaving was performed at 50 ° C. and a pressure of 0.5 MPa for 15 minutes. Then, after storing at 80 ° C. for 500 hours, the sample was returned to room temperature (about 25 ° C.) to obtain an evaluation sample.

  The adhesion state of the sample for evaluation to the glass plate was visually observed and evaluated. The evaluation criteria are as follows.

The optical member did not float or peel off. : ○
The optical member was lifted or peeled off. : ×

<Evaluation of uneven color>
The produced optical member was cut into a size of 24 cm in length and 32 cm in width (15-inch size), and polarized on both sides of an alkali-free glass plate (Corning Corp., 1737, size: 25 × 35 cm, thickness: 0.7 mm). The plate was attached so that the absorption axis of the plate was orthogonal, and autoclaved at 50 ° C. and a pressure of 0.5 MPa for 15 minutes. Then, after storing at 90 ° C. for 500 hours, the sample was returned to room temperature (about 25 ° C.) to obtain an evaluation sample.

Color unevenness did not occur. : ○
Color unevenness occurred. : ×

<Evaluation of warpage of glass plate>
The produced optical member was cut into a size of 24 cm in length and 32 cm in width (15-inch size), and polarized on both sides of an alkali-free glass plate (Corning Corp., 1737, size: 25 × 35 cm, thickness: 0.7 mm). The plate was attached so that the absorption axis of the plate was orthogonal, and autoclaved at 50 ° C. and a pressure of 0.5 MPa for 15 minutes. Then, after storing at 90 ° C. for 100 hours, the sample was returned to room temperature (about 25 ° C.) to obtain an evaluation sample.

  The warpage of the four corners of the glass of the evaluation sample was measured with a displacement meter (Z4W-V25R, manufactured by OMRON Corporation), and an average value was calculated. The evaluation criteria are as follows.

When average value of warpage of glass plate is less than 5 mm: ○
When the average value of the warp of the glass plate is 5 mm or more: ×

<Preparation of (meth) acrylic polymer>
[Acrylic polymer (A)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 80 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of n-butyl acrylate, 2.5 parts by weight of acrylic acid, 2-hydroxyethyl 0.1 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 were charged, and nitrogen substitution was performed by introducing nitrogen gas while gently stirring. Thereafter, a polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare an acrylic polymer (A) solution. The acrylic polymer (A) had a weight average molecular weight of 2.3 million and a glass transition temperature (Tg) of −57 ° C.

[Acrylic polymer (B)]
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 70 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of n-butyl acrylate, 0.5 parts by weight of acrylic acid, 2-hydroxyethyl 0.1 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 were charged, and nitrogen substitution was performed by introducing nitrogen gas while gently stirring. Thereafter, a polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare an acrylic polymer (B) solution. The acrylic polymer (B) had a weight average molecular weight of 22.3 million and a glass transition temperature (Tg) of −55 ° C.

[Acrylic polymer (C)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 50 parts by weight of isooctyl acrylate, 50 parts by weight of n-butyl acrylate, 1 part by weight of acrylic acid, 2-hydroxyethyl acrylate After charging 08 parts by weight, 0.1 part by weight of 2,2′-azobisisobutyronitrile and 200 parts by weight of ethyl acetate as a polymerization initiator, nitrogen gas was introduced while gently stirring, and the flask was purged with nitrogen. The polymerization temperature was kept at around 55 ° C. for 15 hours to prepare an acrylic polymer (C) solution. The acrylic polymer (C) had a weight average molecular weight of 2520,000 and a glass transition temperature (Tg) of −50 ° C.

[Acrylic polymer (D)]
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 65 parts by weight of 2-ethylhexyl acrylate, 35 parts by weight of n-butyl acrylate, 0.8 part by weight of acrylic acid, 2-hydroxybutyl Charge 0.3 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, and introduce nitrogen gas while gently stirring to replace the nitrogen. Thereafter, a polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare an acrylic polymer (D) solution. The acrylic polymer (D) had a weight average molecular weight of 198,000 and a glass transition temperature (Tg) of −48 ° C.

[Acrylic polymer (E)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by weight of n-butyl acrylate, 0.08 parts by weight of 2-hydroxyethyl acrylate, and 2,2′- as a polymerization initiator Charge 0.1 parts by weight of azobisisobutyronitrile and 200 parts by weight of ethyl acetate, introduce nitrogen gas while gently stirring and replace with nitrogen, and then maintain the liquid temperature in the flask at around 55 ° C. for 15 hours. A polymerization reaction was performed to prepare an acrylic polymer (E) solution. The acrylic polymer (E) had a weight average molecular weight of 31110,000 and a glass transition temperature (Tg) of −46 ° C.

[Acrylic polymer (F)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 100 parts by weight of isooctyl acrylate, 0.08 part by weight of 2-hydroxyethyl acrylate, 2,2′-azo as a polymerization initiator Charge 0.1 parts by weight of bisisobutyronitrile and 200 parts by weight of ethyl acetate, introduce nitrogen gas with gentle stirring and replace with nitrogen, and then maintain the liquid temperature in the flask at around 55 ° C. for 15 hours. Reaction was performed and the acrylic polymer (F) solution was prepared. The acrylic polymer (F) had a weight average molecular weight of 2,370,000 and a glass transition temperature (Tg) of −62 ° C.

[Acrylic polymer (G)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 100 parts by weight of n-butyl acrylate, 5 parts by weight of acrylic acid, and 2,2′-azobisisobutyroyl as a polymerization initiator After 0.1 parts by weight of nitrile and 200 parts by weight of ethyl acetate were charged, nitrogen gas was introduced while gently stirring to replace the nitrogen, and then the polymerization temperature was kept at around 55 ° C. for 15 hours to conduct a polymerization reaction. An acrylic polymer (G) solution was prepared. The acrylic polymer (G) had a weight average molecular weight of 2.93 million and a glass transition temperature (Tg) of −38 ° C.

[Acrylic polymer (H)]
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and cooler, 100 parts by weight of isooctyl acrylate, 2.5 parts by weight of acrylic acid, 0.08 part by weight of 2-hydroxyethyl acrylate, polymerization start 2,2′-Azobisisobutyronitrile and 200 parts by weight of ethyl acetate were charged as agents, and nitrogen gas was introduced into the flask while gently stirring and nitrogen substitution was performed. The polymerization reaction was carried out for 15 hours while maintaining the temperature at around 0 ° C. to prepare an acrylic polymer (H) solution. The acrylic polymer (H) had a weight average molecular weight of 1.85 million and a glass transition temperature (Tg) of −53 ° C.

[Acrylic polymer (I)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 30 parts by weight of isooctyl acrylate, 70 parts by weight of n-butyl acrylate, 2.5 parts by weight of acrylic acid, 2-hydroxyethyl acrylate 0.08 parts by weight, 2,2′-azobisisobutyronitrile 0.1 part by weight as a polymerization initiator, and 200 parts by weight of ethyl acetate were charged, and nitrogen gas was introduced while gently stirring to replace the nitrogen. A polymerization reaction was carried out for 15 hours while maintaining the liquid temperature in the flask at around 55 ° C. to prepare an acrylic polymer (I) solution. The acrylic polymer (I) had a weight average molecular weight of 2.63 million and a glass transition temperature (Tg) of −42 ° C.

[Acrylic polymer (J)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 50 parts by weight of isooctyl acrylate, 50 parts by weight of n-butyl acrylate, 5 parts by weight of acrylic acid, 2-hydroxyethyl acrylate 1 part by weight, 0.1 part by weight of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 200 parts by weight of ethyl acetate were charged, and nitrogen gas was introduced while gently stirring, and the flask was purged with nitrogen. The polymerization temperature was kept at around 55 ° C. for 15 hours to prepare an acrylic polymer (J) solution. The acrylic polymer (J) had a weight average molecular weight of 2520,000 and a glass transition temperature (Tg) of −43 ° C.

[Example 1]
(Preparation of pressure-sensitive adhesive solution for optical members)
A trimethylolpropane adduct body of 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and hexamethylene diisocyanate as a crosslinking agent (100 parts by weight of the solid content of the acrylic polymer (A) solution) 0.1 part by weight of Mitsui Takeda Chemical Co., Ltd., D-160N) was added and uniformly mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (1).

(Preparation of optical member with adhesive)
The acrylic pressure-sensitive adhesive solution (1) is applied to one side of a polyethylene-treated polyethylene terephthalate film (manufactured by Toray Industries, Inc., thickness: 38 μm) and heated at 130 ° C. for 3 minutes. A 25 μm pressure-sensitive adhesive layer was formed.

  Subsequently, the said adhesive layer was transcribe | transferred to the surface of the polarizing film, and the optical member with an adhesive was produced. In addition, the gel fraction of the said adhesive layer was 62 weight%.

[Example 2]
(Preparation of pressure-sensitive adhesive solution for optical members)
Except that 0.1 parts by weight of the hexamethylene diisocyanate trimethylolpropane adduct was used, except that 0.1 parts by weight of an isocyanurate of hexamethylene diisocyanate (D-170HN, manufactured by Mitsui Takeda Chemical Co., Ltd.) was used. An acrylic pressure-sensitive adhesive solution (2) was prepared in the same manner as in Example 1.

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (2) was used in place of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 63 weight%.

Example 3
(Preparation of pressure-sensitive adhesive solution for optical members)
The acrylic pressure-sensitive adhesive was prepared in the same manner as in Example 1 except that 0.3 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) was further added to the acrylic pressure-sensitive adhesive solution (1). Solution (3) was prepared.

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (3) was used instead of the acrylic adhesive solution (1). Here, the decomposition amount of the peroxide calculated by theoretical calculation was about 88% by weight. In addition, the gel fraction of the said adhesive layer was 76 weight%.

Example 4
(Preparation of pressure-sensitive adhesive solution for optical members)
100 parts by weight of the solid content of the acrylic polymer (B) solution, 0.1 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a buret body of hexamethylene diisocyanate as a crosslinking agent (Takeshi Mitsui) Chemical Co., Ltd., D-165N) 0.1 parts by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (4).

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (4) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 62 weight%.

Example 5
(Preparation of pressure-sensitive adhesive solution for optical members)
An acrylic pressure-sensitive adhesive was prepared in the same manner as in Example 4 except that 0.2 parts by weight of dibenzoyl peroxide (half-life of 1 minute: 130 ° C.) was further added to the acrylic pressure-sensitive adhesive solution (4). Solution (5) was prepared.

(Preparation of optical member with adhesive)
An optical member with an adhesive was produced in the same manner as in Example 1 except that the acrylic adhesive solution (5) was used instead of the acrylic adhesive solution (1). Here, the decomposition amount of the peroxide calculated by theoretical calculation was about 88% by weight. In addition, the gel fraction of the said adhesive layer was 75 weight%.

Example 6
(Preparation of pressure-sensitive adhesive solution for optical members)
100 parts by weight of the solid content of the acrylic polymer (C) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a hexamethylene diisocyanate burette body (Takeshi Mitsui) as a crosslinking agent Chemical Co., Ltd., D-165N) 0.1 part by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (6).

(Preparation of optical member with adhesive)
An optical member with an adhesive was produced in the same manner as in Example 1 except that the acrylic adhesive solution (6) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 65 weight%.

Example 7
(Preparation of pressure-sensitive adhesive solution for optical members)
An acrylic pressure-sensitive adhesive was prepared in the same manner as in Example 6 except that 0.2 parts by weight of dibenzoyl peroxide (half-life of 1 minute: 130 ° C.) was further added to the acrylic pressure-sensitive adhesive solution (6). Solution (7) was prepared.

(Preparation of optical member with adhesive)
An optical member with an adhesive was produced in the same manner as in Example 1 except that the acrylic adhesive solution (7) was used instead of the acrylic adhesive solution (1). Here, the decomposition amount of the peroxide calculated by theoretical calculation was about 88% by weight. In addition, the gel fraction of the said adhesive layer was 77 weight%.

Example 8
(Preparation of pressure-sensitive adhesive solution for optical members)
To 100 parts by weight of the solid content of the acrylic polymer (D) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and an isocyanurate of hexamethylene diisocyanate as a crosslinking agent (Takeshi Mitsui) Chemical Co., Ltd., D-170HN) 0.04 parts by weight and tolylene diisocyanate trimethylolpropane adduct (0.03 parts by Mitsui Takeda Chemical Co., D-101N) are added and mixed and stirred uniformly. 0.1 parts by weight of dibenzoyl peroxide (1 minute half-life: 130 ° C.) was added to prepare an acrylic pressure-sensitive adhesive solution (8).

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (8) was used instead of the acrylic adhesive solution (1). Here, the decomposition amount of the peroxide calculated by theoretical calculation was about 88% by weight. In addition, the gel fraction of the said adhesive layer was 71 weight%.

[Comparative Example 1]
(Preparation of pressure-sensitive adhesive solution for optical members)
100 parts by weight of the solid content of the acrylic polymer (E) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a hexamethylene diisocyanate burette body as a cross-linking agent (Takeshi Mitsui) Chemical Co., Ltd., D-165N) 0.1 part by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (9).

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (9) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 60 weight%.

[Comparative Example 2]
(Preparation of pressure-sensitive adhesive solution for optical members)
100 parts by weight of the solid content of the acrylic polymer (F) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a buret body of hexamethylene diisocyanate as a crosslinking agent (Takeda Mitsui) Chemical Co., Ltd., D-165N) 0.1 part by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (10).

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (10) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 65 weight%.

[Comparative Example 3]
(Preparation of pressure-sensitive adhesive solution for optical members)
100 parts by weight of the solid content of the acrylic polymer (G) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a hexamethylene diisocyanate burette body (Takeshi Mitsui) as a crosslinking agent Chemical Co., Ltd., D-165N) 0.4 part by weight was added and mixed and stirred uniformly to try to prepare an acrylic pressure-sensitive adhesive solution (11). The optical part could not be produced.

[Comparative Example 4]
(Preparation of pressure-sensitive adhesive solution for optical members)
100 parts by weight of the solid content of the acrylic polymer (H) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a buret body of hexamethylene diisocyanate as a crosslinking agent (Takeda Mitsui) Chemical Co., Ltd., D-165N) 0.1 part by weight was added and mixed and stirred uniformly to prepare an acrylic pressure-sensitive adhesive solution (12).

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (12) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 68 weight%.

[Comparative Example 5]
(Preparation of pressure-sensitive adhesive solution for optical members)
To 100 parts by weight of the solid content of the acrylic polymer (I) solution, 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and a trimethylolpropane adduct of hexamethylene diisocyanate as a crosslinking agent ( 0.1 part by weight of Mitsui Takeda Chemical Co., Ltd., D-160N) was added and uniformly mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (13).

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (13) was used in place of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 69 weight%.

[Comparative Example 6]
(Preparation of pressure-sensitive adhesive solution for optical members)
A trimethylolpropane adduct body of 0.1 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent and hexamethylene diisocyanate as a crosslinking agent (100 parts by weight of the solid content of the acrylic polymer (J) solution) 0.1 part by weight of Mitsui Takeda Chemical Co., Ltd., D-160N) was added and uniformly mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution (14).

(Preparation of optical member with adhesive)
An optical member with an adhesive was produced in the same manner as in Example 1 except that the acrylic adhesive solution (14) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 71 weight%.

[Comparative Example 7]
(Preparation of pressure-sensitive adhesive solution for optical members)
Instead of using 0.1 parts by weight of the trimethylolpropane adduct of hexamethylene diisocyanate, 0.005 parts by weight of trimethylolpropane adduct of hexamethylene diisocyanate (D-160N, Mitsui Takeda Chemical Co., Ltd.) was used. Prepared an acrylic pressure-sensitive adhesive solution (15) in the same manner as in Example 1.

(Preparation of optical member with adhesive)
An optical member with an adhesive was prepared in the same manner as in Example 1 except that the acrylic adhesive solution (15) was used instead of the acrylic adhesive solution (1). In addition, the gel fraction of the said adhesive layer was 20 weight%.

  According to the said method, durability (humidification test, heat test) of the produced optical member with an adhesive, color unevenness, and the curvature of the glass plate were evaluated. The obtained results are shown in Table 1.

  From the results of Table 1 above, when the pressure-sensitive adhesive optical member produced according to the present invention was used (Examples 1 to 8), in any of the examples, durability (exfoliation and It has been revealed that foaming does not occur) and that the stress caused by the dimensional change of the optical member (polarizing plate) is excellent, and there is no adverse effect (color unevenness) on the liquid crystal display state.

  On the other hand, when using an optical member with an adhesive that does not satisfy the configuration of the present invention (Comparative Examples 1 to 7), in any Comparative Example, durability after high-temperature and high-humidity treatment, stress relaxation, and As a result, it was not possible to make all of the suppression of color unevenness side by side, and it became clear that it was not suitable for an optical member with an adhesive, especially when the screen was enlarged.

As described above, the optical member with a pressure-sensitive adhesive of the present invention has excellent removability, durability, and stress relaxation property even when stored under severe processing conditions, and suppresses occurrence of color unevenness. It was found that the optical member with pressure-sensitive adhesive had both stress relaxation properties and durability, with warpage suppressed even when screened.

Claims (8)

As a monomer unit,
Radical polymerizable monomer (A1) whose homopolymer has a glass transition temperature of −70 to −55 ° C. and 40 to 95% by weight, and Radical polymerizable monomer (A2) whose homopolymer has a glass transition temperature of −50 to 0 ° C. ) 100 parts by weight of a radically polymerizable monomer (A) comprising 5 to 60% by weight,
0.1 to 3 parts by weight of unsaturated carboxylic acid monomer (B), and
0.01 to 3 parts by weight of a monomer (C) containing a hydroxyl group,
Containing 100 parts by weight of (meth) acrylic polymer having a glass transition temperature of −45 ° C. or less,
An adhesive composition for optical members, comprising 0.01 to 0.1 parts by weight of an isocyanate-based crosslinking agent and 0.02 to 2 parts by weight of a peroxide.   The pressure-sensitive adhesive composition for an optical member according to claim 1, wherein the crosslinking agent is a hexamethylene diisocyanate compound.   The process of forming the layer which consists of an adhesive composition for optical members of Claim 1 or 2 on the single side | surface or both surfaces on the support body which carried out peeling process, and decomposition | disassembly of the peroxide in the said adhesive composition for optical members And a step of heat-treating the layer made of the pressure-sensitive adhesive composition for optical members so that the amount is 75% by weight or more.   The pressure-sensitive adhesive layer for optical members obtained by the production method according to claim 3, wherein the pressure-sensitive adhesive layer for optical members has a gel fraction of 45 to 90% by weight.   A pressure-sensitive adhesive layer for optical members, wherein the pressure-sensitive adhesive composition for optical members according to claim 1 or 2 is crosslinked.   The pressure-sensitive adhesive layer for optical members according to claim 5, wherein the pressure-sensitive adhesive layer for optical members has a gel fraction of 45 to 90% by weight. An optical member with an adhesive for an optical member for the pressure-sensitive adhesive layer and characterized by being formed on one or both sides of the optical member according to any one of claims 4-6.   An image display device using at least one optical member with an adhesive according to claim 7.