JP2005344014A - Method for adjusting peel strength, adhesive layer for optical member and method for producing the same, optical member with adhesive and image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily adjusting peel strength of a silicone release liner without using a silicone component such as a heavy release agent, to provide an adhesive layer for optical members which has excellent durability and suitable peel strength and a method for producing the same, and to provide an optical member with an adhesive having the adhesive layer and an image display device using the same. <P>SOLUTION: The method for adjusting peel strength of a silicone release liner comprises the steps of providing an adhesive composition layer containing a base polymer and a peroxide on a release-treated surface of the silicone release liner and thermally decomposing a part or all of the peroxide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for adjusting the release force of a silicone release liner, an adhesive layer for an optical member in which an adhesive layer is laminated on the release-treated surface of a silicone release liner, a method for producing the same, and an optical member with an adhesive. Furthermore, the present invention relates to an image display device such as a liquid crystal display device, an organic EL display device, and a PDP using the optical member pressure-sensitive adhesive layer. Examples of the optical member include a polarizing plate, a retardation plate, an optical compensation film, a brightness enhancement film, and those in which these are laminated.

  An optical member used for a liquid crystal display device or the like, for example, a polarizing plate or a retardation plate is attached to a liquid crystal cell using an adhesive. Usually, an optical member with an adhesive in which an adhesive layer is laminated on an optical member is used. Since the material used for the optical member has a large expansion and contraction under heating and humidification conditions, it tends to float and peel off after being attached. For this reason, the pressure-sensitive adhesive for optical members is required to have durability that can cope with heating conditions and humidification conditions.

  Further, these optical members with pressure-sensitive adhesives usually show smoothness integrated with a release liner that has been subjected to a silicone release treatment. As the release liner for the optical member with the pressure-sensitive adhesive, a release liner in which a PET film is precisely coated with silicone is used because it is excellent in transparency, heat resistance and smoothness and has few appearance defects.

  This silicone release liner is removed when it is no longer needed, but if the release force of the silicone release liner is too high when it is removed, it will be difficult to remove when the release liner is removed, while if it is too small, it will be punched. Thus, there arises a problem that the release liner floats or peels off during the optical member manufacturing process, and an appropriate peeling force is required.

As a method for adjusting the appropriate peeling force, for example, a method of changing the amount of the silicone component used has been proposed (see, for example, Patent Documents 1 and 2). However, if the release force is adjusted by using, for example, a heavy release agent for the silicone component, the heavy release agent may be transferred to the adhesive surface and deteriorate the adhesive properties. Further, it has been found that when the silicone release liner is wound with a raw fabric, the heavy release agent is transferred to the back surface, causing problems when the release liner is peeled off.
JP-A-6-298875 JP 2000-199199 A

  Then, the objective of this invention aims at providing the adjustment method of the peeling force of a silicone release liner easily, without using silicone components, such as a heavy release agent. Another object of the present invention is to provide a pressure-sensitive adhesive layer for optical members that is excellent in durability and has an appropriate peeling force, and a method for producing the same. Furthermore, it is providing the optical member with an adhesive which has the said adhesive layer, and an image display apparatus using the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the above-described object can be achieved by using the following method as a method for adjusting the release force of the silicone release liner, and the present invention has been completed. .

  That is, the method for adjusting the release force of the silicone release liner of the present invention includes a step of providing a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on the release-treated surface of the silicone release liner, and a part of the peroxide or And the step of thermally decomposing the whole.

  The method for producing a pressure-sensitive adhesive layer with a silicone release liner according to the present invention includes the step of providing a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on the release-treated surface of a silicone release liner. A method comprising the step of adjusting the release force of a silicone release liner.

  According to the method for adjusting the release force of the silicone release liner of the present invention, as shown in the results of Examples, a step of forming a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide, and a part of the peroxide Alternatively, the release force of the silicone release liner can be easily adjusted by using a method for adjusting the release force of the silicone release liner including the step of thermally decomposing the whole. Although the details of why the release force of the silicone release liner can be easily adjusted by the above adjustment method are not clear, the hydrogen abstraction reaction in the silicone molecule by radical active species generated by thermal decomposition of the peroxide in the pressure-sensitive adhesive composition It is estimated that the silicone surface is modified as a result.

  In the method for adjusting the peel strength of the silicone release liner, it is preferable to thermally decompose 1 to 20 μmol of the peroxide with respect to 1 g of the pressure-sensitive adhesive composition. By adjusting the amount of peroxide, an appropriate peeling force can be expressed and the peeling force can be adjusted.

  The method for producing a pressure-sensitive adhesive layer with a silicone release liner according to the present invention includes the step of providing a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on the release-treated surface of a silicone release liner. A method comprising the step of adjusting the release force of a silicone release liner. By using this production method, it is possible to obtain a pressure-sensitive adhesive layer for an optical member that is excellent in durability and has an appropriate peeling force.

  In the production method of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive composition contains, as a base polymer, a (meth) acrylic polymer having 80 parts by weight or more of a (meth) acrylic acid alkyl ester in 100 parts by weight of the monomer component. Is preferred. By using this pressure-sensitive adhesive composition, it is possible to obtain a pressure-sensitive adhesive layer for an optical member that is excellent in durability and has an appropriate peeling force.

  Moreover, in the manufacturing method of the said adhesive layer, 0.01-1 weight part of silane coupling agents can be contained in 100 weight part of adhesive compositions. By using this pressure-sensitive adhesive composition, it is possible to obtain a pressure-sensitive adhesive layer for an optical member that is excellent in durability and has an appropriate peeling force.

  On the other hand, the method for producing a pressure-sensitive adhesive sheet with a silicone release liner according to the present invention includes a step of providing a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on the release-treated surface of a silicone release liner. In the sheet manufacturing method, the release force of the silicone release liner is adjusted to be in the range of 0.1 to 0.4 N / 50 mm by the step of thermally decomposing part or all of the peroxide. To do. By using this production method, it is possible to obtain pressure-sensitive adhesive sheets with a silicone release liner that have excellent durability and an appropriate peeling force.

  On the other hand, the pressure-sensitive adhesive layer for optical members of the present invention is produced by the above method. Since the pressure-sensitive adhesive layer of the present invention exhibits the above-described effects, by using the pressure-sensitive adhesive layer of the present invention, it is possible to obtain pressure-sensitive adhesive sheets for optical members that have excellent durability and an appropriate peeling force. Therefore, it is particularly useful as a re-peelable pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive sheet for optical members of the present invention is obtained by forming a pressure-sensitive adhesive layer produced by the above method on a release liner. According to the pressure-sensitive adhesive sheet for optical members of the present invention, the pressure-sensitive adhesive sheet for optical members having excellent durability and an appropriate peeling force is provided because the pressure-sensitive adhesive layer having the above-described effects is provided.

  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 pressure-sensitive adhesive of the present invention, since the pressure-sensitive adhesive layer having the above-described effects is provided, the optical member with pressure-sensitive adhesive has excellent durability and an appropriate peeling force.

  Further, 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 optical member with an adhesive, and does not cause peeling or foaming even when stored in a high temperature and high humidity state. Even when the image display device is reused by peeling off the optical member due to durability, the adhesive force does not increase, and it has a function of easily peeling without adversely affecting the device.

  The method for adjusting the release force of the silicone release liner according to the present invention includes a step of providing a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on the release-treated surface of the silicone release liner, and a part or all of the peroxide. And the step of thermally decomposing them.

  In the step of providing the layer of the pressure-sensitive adhesive composition of the present invention, hot-melt coating that does not use a dispersion solvent of the pressure-sensitive adhesive composition may be used, but a dispersion solvent is used to improve the coating accuracy. It is preferable.

  The dispersion solvent is not particularly limited, and for example, organic solvents such as toluene, ethyl acetate, alcohols, and ketones, water, and the like can be appropriately used. Further, coating using the solvent used for polymer polymerization directly is also possible, and a solvent may be added as appropriate. These solvents may be used alone or in combination of two or more.

  As shown in “Adhesive Handbook (2nd edition), P174, edited by Adhesive Tape Industry Association, 1995.10.12”, the silicone release liner has a condensation reaction type silicone release agent (for example, a base polymer at both ends). A polydimethylsiloxane having a hydroxyl group, a polymethylhydrosiloxane siloxane as a crosslinking agent, and a tin-based catalyst as a catalyst are generally used, and an addition reaction type silicone release agent (for example, both ends as a base polymer) A polydimethylsiloxane having a hydroxyl group in which a part of the methyl group is substituted with a vinyl group, a polymethylhydrosiloxane siloxane as a crosslinking agent, and a platinum catalyst as a catalyst are generally used) However, the present invention is not particularly limited, and any release agent is used. It may be a release liner.

  The peroxide of the present invention can be appropriately used as long as it generates radical active species by heating and reacts with the silicone of the release liner. However, in consideration of workability and stability, it has a half-life of 1 minute. It is preferable to use a peroxide having a temperature of 80 ° C to 160 ° C, and it is more preferable to use a peroxide having a temperature of 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. 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 and the like, for example, the organic peroxide catalog 9th edition (Nippon Yushi Co., Ltd.) (May 2003).

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

  The pressure-sensitive adhesive composition in the present invention is applied to a release liner that has been subjected to a release treatment and then dried to form a layer of the pressure-sensitive adhesive composition. Moreover, you may transfer the layer of the adhesive composition formed on the other base material to a peeling liner.

  In the peeling force adjusting method in the present invention, in addition to adjusting the amount of peroxide, the decomposition treatment temperature and the decomposition treatment time are important.

  The peroxide decomposition amount in the present invention is preferably 1 to 20 μmol, more preferably 2 μmol to 16 μmol, and further preferably 2 μmol to 12 μmol with respect to 1 g of the pressure-sensitive adhesive composition. If the amount of peroxide decomposition is less than 1 μmol, the peel force tends to be too small. On the other hand, if it is more than 20 μmol, the peel force tends to be too large, which is not preferable.

  The peroxide is preferably used in an amount of 0.02 to 2 parts by weight, more preferably 0.05 to 1 part by weight, based on 100 parts by weight of the pressure-sensitive adhesive composition. When the amount is less than 0.02 parts by weight, the peeling force of the separator tends to be too small. On the other hand, when the amount is more than 2 parts by weight, the peeling force tends to be too large, and the peroxide layer is overoxidized. Since a large amount of the material remains, the adhesive property may change over time.

  With respect to the decomposition treatment temperature and the decomposition treatment time of the peroxide, the amount of decomposition of the peroxide is 1 μmol to 20 μmol, preferably 2 μmol to 16 μmol, more preferably 2 μmol to 12 μmol per 1 g of the pressure-sensitive adhesive composition. If it can be controlled, there is no particular problem, but if a temperature of 170 ° C. or higher is applied, a side reaction may occur. The temperature at the time of drying may be used as it is as the decomposition treatment temperature, or the decomposition treatment may be performed after drying. The processing time is set in consideration of productivity and workability, but is usually about 0.2 to 20 minutes, and preferably about 0.5 to 10 minutes.

  Although it will not specifically limit as an adhesive composition used for this invention if it has adhesiveness applicable to what was mentioned above, The adhesive composition which uses a (meth) acrylic-type polymer as a base polymer is preferable.

  As the (meth) acrylic acid alkyl ester used as the monomer component of the base polymer, an ester with an alcohol having 12 or less carbon atoms is used. Particularly preferred are (meth) acrylic monomers having an alkyl group having 4 to 12 carbon atoms.

  Examples of the (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, t-butyl (meth) acrylate, and isobutyl (meth). Acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate N-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, and the like. These acrylic monomers may be used alone or in combination of two or more.

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

  As the (meth) acrylic polymer, a (meth) acrylic polymer having 80 parts by weight or more of (meth) acrylic acid alkyl ester in 100 parts by weight of the monomer component is particularly preferable.

  The ratio of the (meth) acrylic acid alkyl ester in the (meth) acrylic polymer is preferably 80 parts by weight or more (for example, about 80 to 99.8 parts by weight) in 100 parts by weight of the monomer component, 85 It is more preferable that the amount is at least parts by weight (for example, about 85 to 99.5 parts by weight). If it is less than 80 parts by weight, the stress relaxation property is poor, which is not preferable.

  In the present invention, a functional group-containing monomer containing a functional group such as a hydroxyl group can be used. The kind of the functional group can be appropriately selected.

  Specific examples of the functional group-containing monomer include (meth) acrylic acid, itaconic acid, maleic acid, crotonic acid, maleic anhydride, 2- (meth) acryloyloxyethyl succinic acid, and 2- (meth) acrylic acid. Carboxyl group-containing monomers such as leuoxyethylphthalic acid or anhydrides thereof, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, N- Amide group-containing monomers such as butoxymethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3 -Hydroxybutyl (meta Hydroxyl group-containing monomers such as acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, amino group-containing monomers such as dimethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, Examples include glycidyl group-containing monomers such as glycidyl (meth) acrylate, (meth) acrylonitrile, N- (meth) acryloylmorpholine, N-vinyl-2-pyrrolidone and the like.

  Although the said functional group containing monomer may be used independently and may be combined, the content as a whole is 0.01-20 weight part in 100 weight part of monomer components of a (meth) acrylic-type polymer. It is preferable that it is 0.05 to 10 parts by weight. When the content of the functional group-containing monomer is less than 0.01 parts by weight, it is not preferable because crosslinking is insufficient and durability may be inferior. On the other hand, when the content of the functional group-containing monomer exceeds 20% by weight, the adhesive force to the liquid crystal cell or the like tends to be too large, which is not preferable.

  The (meth) acrylic polymer used in the present invention has a weight average molecular weight of 100,000 to 5,000,000, preferably 200,000 to 4,000,000, more preferably 300,000 to 3,000,000. When the weight average molecular weight is smaller than 100,000, the adhesive force tends to be generated due to a decrease in the cohesive force of the pressure-sensitive adhesive composition. On the other hand, when the weight average molecular weight exceeds 5,000,000, the fluidity of the polymer is lowered, the wetting to the polarizing plate becomes insufficient, and air remains between the pressure-sensitive adhesive composition layer such as the release liner and the optical member. There is a tendency to cause. The weight average molecular weight in the present invention refers to that obtained by measurement by GPC (gel permeation chromatography).

  The glass transition temperature (Tg) of the (meth) acrylic polymer is 0 ° C. or lower (usually −100 ° C. or higher), preferably −10 ° C. or lower. When the glass transition temperature is higher than 0 ° C., the polymer is difficult to flow and the wetting of the polarizing plate is insufficient, and air tends to remain between the polarizing plate and the pressure-sensitive adhesive composition layer of the surface protective film. is there. In addition, Tg of a (meth) acrylic-type polymer can be adjusted in the said range by changing suitably the monomer component and composition ratio to be used. The glass transition temperature (Tg) in this invention says what was obtained by measuring with the measuring method using a dynamic viscoelasticity apparatus.

  The polymerization method of the (meth) acrylic polymer used in the present invention is not particularly limited, and can be appropriately polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization or the like. In addition, the obtained polymer may be any of a random polymer, a block polymer, and the like. For example, when using solution polymerization, 0.01 to 0.2 parts by weight of a polymerization initiator such as azobisisobutyronitrile is blended with 100 parts by weight of a monomer, and a polymerization solvent such as ethyl acetate is used. And a predetermined (meth) acrylic-type polymer can be obtained by making it react at 50-70 degreeC for 8 to 30 hours under nitrogen stream.

  In the present invention, a peroxide can also be used as a polymerization initiator in the polymerization of a (meth) acrylic polymer or the like. In such a case, there is a case where the polymer does not react during the polymerization reaction and then remains in the layer of the pressure-sensitive adhesive composition. May be adjusted. At this time, the remaining amount of the unreacted peroxide can be quantified, and a peroxide can be added as necessary to obtain a predetermined peroxide amount.

  As the silane coupling agent in the present invention, those conventionally known can be used without particular limitation. For example, epoxy groups such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane -Containing silane coupling agent, 3-aminopropyltrimethoxysilane, N-2- (aminoethyl) -3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethylbutylidene) propylamine Amino group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane, (meth) acrylic group-containing silane coupling agents such as 3-methacryloxypropyltriethoxysilane, and isocyanates such as 3-isocyanatopropyltriethoxysilane Such as group-containing silane coupling agent.

  In the present invention, the silane coupling agent is blended in an amount of 0.01 to 1 part by weight, preferably 0.02 to 0.6 part by weight, based on 100 parts by weight of the solid content of the acrylic polymer. When the blending amount increases, the adhesive strength to the liquid crystal cell or the like increases and the removability may decrease. On the other hand, when it is too small, the durability may decrease.

  The pressure-sensitive adhesive composition of the present invention is more excellent in heat resistance by appropriately crosslinking a (meth) acrylic polymer. As the crosslinking agent used in the present invention, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, a metal chelate compound, and the like are used. Among these, an isocyanate compound and an epoxy compound are particularly preferably used mainly from the viewpoint of obtaining an appropriate cohesive force. In particular, in the production of a polymer, a hydroxyl group is introduced into the polymer by copolymerizing a hydroxyl group-containing monomer such as 2-hydroxyethyl acrylate, and a polyisocyanate compound is used as a crosslinking agent for the polymer. preferable. These compounds may be used alone or in combination.

  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, 2,4-tolylene diisocyanate, Aromatic isocyanates such as 4,4′-diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene Diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), isocyanurate of hexamethylene diisocyanate Body (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) isocyanate adducts such as, such as diisocyanate adduct of the polyol, and the like. These compounds may be used alone or in combination.

  Examples of the epoxy compound include N, N, N ′, N′-tetraglycidyl-m-xylenediamine (trade name: TETRAD-X, manufactured by Mitsubishi Gas Chemical Company) and 1,3-bis (N, N-diglycidyl). Aminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.). These compounds may be used alone or in combination.

  Examples of the melamine resin include hexamethylol melamine. Examples of the aziridine derivative include a commercially available product name HDU (manufactured by Mutual Pharmaceutical Company), a product name TAZM (manufactured by Mutual Pharmaceutical Company), and a product name TAZO (manufactured by Mutual Pharmaceutical Company). These compounds may be used alone or in combination.

  Examples of the metal chelate compound include aluminum, iron, tin, titanium, and nickel as metal components, and acetylene, methyl acetoacetate, and ethyl lactate as chelate components. These compounds may be used alone or in combination.

  The content of the crosslinking agent used in the present invention is usually about 0.01 to 5 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer, but the gel content after crosslinking with the crosslinking agent is 45 to 95% by weight. It is preferable to adjust the amount of the crosslinking agent so as to be%, and it is more preferable to adjust the amount of the crosslinking agent so as to be 50 to 85% by weight. When the gel content is lower than 45% by weight, problems such as foaming occur in the heating test, and the cohesive force of the pressure-sensitive adhesive composition tends to be reduced, which tends to cause adhesive residue. On the other hand, when the gel content is higher than 95% by weight, the cohesive force of the pressure-sensitive adhesive composition tends to increase and the adhesiveness tends to be poor.

  The gel content of the pressure-sensitive adhesive composition in the present invention indicates the ratio of the cross-linked portion in the pressure-sensitive adhesive layer as the degree of crosslinking.

The method for measuring the gel content is shown below. About 0.1 g of the pressure-sensitive adhesive layer immediately after the crosslinking treatment was taken and weighed to obtain the weight part W ₁ (g) of the pressure-sensitive adhesive layer. Next, the pressure-sensitive adhesive layer is wrapped in a microporous tetrafluoroethylene film (the weight of the film after wrapping is defined as W ₂ (g)), immersed in about 50 ml of acetic acid at about 25 ° C. for 2 days, Was extracted and removed. Next, the pressure-sensitive adhesive layer was taken out from ethyl acetate, and the weight W ₃ (g) after drying at 110 ° C. for 1 hour was measured. From these measured values, the gel fraction (% by weight) of the pressure-sensitive adhesive layer was determined according to the following formula. Moreover, the gel fraction after storing for 1 week at room temperature after coating was measured.

Gel fraction (% by weight) = (W ₃ −W ₂ / W ₁ ) × 100
The pressure-sensitive adhesive composition of the present invention has the above (meth) acrylic polymer as a base polymer.

  In the pressure-sensitive adhesive layer in the present invention, as optional components, in addition to the above components, various tackifiers such as phenol resin, terpene-phenol resin, terpene resin, xylene resin, rosin, hydrogenated rosin, calcium carbonate, carbon black, etc. Powders such as inorganic fillers, lubricants, anti-aging agents, colorants, pigments, surfactants, plasticizers, antifoaming agents, light stabilizers, thixotropic agents, UV absorbers, low molecular weight polymers, surface lubricants, Leveling agents, antioxidants, polymerization inhibitors, heat stabilizers, hydrolysis stabilizers and other stabilizers, metal powders, particles, foils, and the like can be used as appropriate. These arbitrary components may be used individually by 1 type, or may use 2 or more types.

  The thickness of the pressure-sensitive adhesive layer used in the present invention is preferably 2 μm to 500 μm after drying, and more preferably 5 μm to 100 μm. When the thickness is smaller than 2 μm, the adhesive strength to the optical member becomes insufficient, and when the thickness exceeds 500 μm, the adhesive strength is saturated, which is not economical, and the adhesive sticks out or causes cohesive failure and is difficult to peel.

  The pressure-sensitive adhesive layer of the present invention is formed by forming a pressure-sensitive adhesive layer containing such a pressure-sensitive adhesive composition on a silicone release liner that has been subjected to a release treatment. At that time, the formation of the pressure-sensitive adhesive layer is generally carried out by volatilizing the solvent after application of the pressure-sensitive adhesive composition solution, but the pressure-sensitive adhesive layer obtained by volatilizing the solvent from the pressure-sensitive adhesive composition solution is peeled off. It can also be formed by transferring to a treated substrate or the like. Further, a pressure-sensitive adhesive layer may be formed by applying a pressure-sensitive adhesive composition by a roll coater such as a reverse coater or a gravure coater, a curtain coater, a lip coater, a die coater, a roll brush, a spray coat, an air knife coat method, or the like. . Further, for example, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction after application. In addition, when applying the pressure-sensitive adhesive composition to the release-treated silicone release liner, one or more solvents other than the polymerization solvent are newly added to the composition so that the adhesive composition can be uniformly applied onto the release-treated substrate. May be. Examples of the release liner subjected to the release treatment include a silicone release liner obtained by subjecting a PET film to a silicone release treatment.

  The pressure-sensitive adhesive sheets of the present invention use a silicone release liner formed so that the thickness of the pressure-sensitive adhesive layer is usually 2 to 500 μm, preferably about 5 to 100 μm, a plastic film such as a polyester film, paper, It is formed on one side or both sides of various supports made of a porous material such as a nonwoven fabric, and is in the form of a sheet or tape.

  The support constituting the pressure-sensitive adhesive sheet is preferably a resin film having heat resistance and solvent resistance and flexibility. Applying the adhesive composition by roll coater such as reverse coater and gravure coater, curtain coater, lip coater, die coater, roll brush, spray coat, air knife coat method, etc., because the support has flexibility Can be wound up into a roll.

  The resin for forming the support film as the support is not particularly limited as long as it can be formed into a sheet or film. For example, polyethylene, polypropylene, poly-1-butene, poly-4-methyl -1-pentene, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, polyolefin film such as ethylene / vinyl alcohol copolymer, polyethylene Polyester film such as terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinyl chloride Den film, polycarbonate film, fluorine-containing resins such as polyfluoroethylene, polyimide, nylon, cellulose and the like.

  In addition, in order to improve the adhesiveness between an adhesive layer and a support film, you may perform corona treatment etc. on the surface of a support film. Moreover, you may perform a back surface process to a support film.

  The thickness of the film is usually about 5 to 200 μm, preferably about 10 to 100 μm.

  The manufacturing method of the adhesive layer for optical members of this invention includes the process of apply | coating on the silicone release liner which peeled the said adhesive composition, and making it dry, and carrying out the thermal decomposition process of the said peroxide. This step is as described above.

In the optical member of the present invention, the pressure-sensitive adhesive layer formed by the above-described production method is formed by forming a pressure-sensitive adhesive layer on one side or both sides of an optical member such as a polarizing plate.
When the pressure-sensitive adhesive layer is exposed on the surface, it is appropriately protected with a peeled sheet or the like until it is put to practical use.

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

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. Examples thereof include polyene-based oriented films such as those obtained by adsorbing 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, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the transparent protective film. The transparent protective film can also be formed as a cured layer of 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, transparent protection of 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 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 method or a compounding method of transparent fine particles. Examples of the fine particles to be included in the formation of the surface fine concavo-convex structure include a conductive material made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle diameter of 0.5 to 50 μm. Transparent fine particles such as inorganic fine particles, organic fine particles composed of a crosslinked or uncrosslinked polymer, etc. may be used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

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

  The optical member of the present invention includes, for example, a liquid crystal display device such as a reflecting plate, a semi-transmissive plate, a retardation plate (including wavelength plates such as 1/2 and 1/4), a viewing angle compensation film, and a brightness enhancement film. What becomes an optical layer which may be used for formation of this is mention | raise | lifted. These can be used alone as the optical member of the present invention, and can be laminated on the polarizing plate for practical use and used in one or more layers.

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

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. Moreover, the transparent protective film contains fine particles so as to have a surface fine concavo-convex structure and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. The transparent protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it, and light and dark unevenness can be further suppressed. The reflective layer having a fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film can be formed by, for example, depositing a metal by an appropriate method such as a vacuum deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the transparent protective layer.

  The reflection plate can be used as a reflection sheet in which a reflection layer is provided on an appropriate film according to the transparent film, instead of directly applying to the transparent protective film of the polarizing plate. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which 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 are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or by obliquely depositing silicon oxide. This is done by developing and heat treatment.

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

  The viewing angle compensation film is a film for widening the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a viewing angle compensation phase difference plate, for example, a phase difference plate, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and contracting the polymer film under the action of the contraction force by heating, or a film obtained by obliquely aligning a liquid crystal polymer. Is mentioned. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

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

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to 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 on the surface of the brightness enhancement film is further inverted through a reflective layer or the like 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. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly, resulting in a dark image. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer 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., the brightness unevenness of the display screen is reduced at the same time, 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. It is preferable to make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region has, for example, a retardation layer that functions as a quarter-wave plate for light-color light having 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, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as a visible light region by combining two or more layers having different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or 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 a liquid crystal display device or the like can be improved because of excellent stability and assembly work. For the lamination, an appropriate adhesive means such as a pressure-sensitive adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

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

  The pressure-sensitive adhesive optical member of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. In other words, 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 structure having various combinations such as a laminate of such a light-emitting layer and an electron injection layer made of a perylene derivative, or a stack 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.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In addition, the evaluation items in Examples and the like were measured as follows. In the examples,% is based on weight.

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

Device: HLC-8120GPC, manufactured by Tosoh Corporation
column:
Sample column: G7000H _XL + GMH _XL + GMH _XL manufactured by Tosoh Corporation
Flow rate: 0.8ml / min
Injection volume: 100 μl
Column temperature: 40 ° C
Eluent: THF
Injection sample concentration: 0.1% by weight
Detector: differential refractometer The weight average molecular weight was calculated in terms of polystyrene.

<Measurement of peroxide decomposition amount>
The amount of peroxide decomposition after the thermal decomposition treatment was measured by HPLC (high performance liquid chromatography).

  About 0.2 g of each pressure-sensitive adhesive composition before and after the decomposition treatment was taken out, immersed in 10 ml of ethyl acetate, extracted with shaking at 25 ° C. and 120 rpm for 3 hours, and then allowed to stand at room temperature 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 decrease in the peroxide amount was defined as the peroxide decomposition amount.

Equipment: HPL CCPM / UV8000, manufactured by Tosoh Corporation
column:
Sample column; manufactured by MACHEREY-NAGEL, NUCLEOSIL 7C18 (4.6 mmφ × 250 mm)
Flow rate: 1.0ml / min
Column pressure: 41 Kg / cm ²
Column temperature: 40 ° C
Eluent: Water / acetonitrile = 30/70
Injection volume: 10 μl
Injection sample concentration: 0.01% by weight
Detector: UV detector (230 nm)
<Measurement of peel strength of release liner>
The peelable force of the release liner was measured when the produced optical member with a release liner cut to a size of 50 mm in width and 100 mm in length was peeled off at a peeling speed of 300 mm / min (peeling angle 180 °) with a universal tensile testing machine. . The measurement was performed in an environment of 23 ° C. × 50% RH. When the peeling force is less than 0.1 N / 50 mm, the peeling force is too small, and thus a problem such as the release liner floating easily occurs in a manufacturing process such as punching. On the other hand, when it is larger than 0.4 N / 50 mm, the peeling force becomes too large, and thus the problem that peeling of the release liner becomes difficult during actual use tends to occur.

<Durability evaluation>
The produced optical member (12-inch size) was attached to an alkali-free glass plate (manufactured by Corning, trade name Corning 1737, 250 × 350 mm, thickness: 0.7 mm), and 30 minutes at 50 ° C. and a pressure of 0.5 MPa. Autoclaving was performed. Then, after storing at 60 ° C. × 90% RH for 500 hours, the sample was returned to room temperature to obtain an evaluation sample. The state of adhesion to the glass plate after this treatment was confirmed and evaluated according to the following criteria.

The optical member did not float or peel off: ○
The optical member was lifted or peeled off: ×
(Example 1)
95 parts by weight of butyl acrylate, 3.0 parts by weight of acrylic acid, 0.10 parts by weight of 2-hydroxyethyl acrylate, 0.050 part by weight of 2,2-azobisisobutyronitrile and 200 parts by weight of ethyl acetate After putting into a four-necked flask equipped with an introduction tube and a cooling tube, and sufficiently purging with nitrogen, a polymerization reaction is carried out at 55 ° C. for 20 hours with stirring under a nitrogen stream, and a high molecular weight acrylic having a weight average molecular weight of 1,570,000. A solution of polymer A was obtained.

  Dibenzoyl peroxide (1 minute half-life: 130.0 ° C.) 0.15 parts by weight with respect to 100 parts by weight of the acrylic polymer A solution (solid content), 3-glycidoxypropyl as a silane coupling agent 0.080 parts by weight of trimethoxysilane and 0.60 part by weight of an isocyanate-based crosslinking agent (coronate L, manufactured by Nippon Polyurethane Co., Ltd.) consisting of a tolylene diisocyanate adduct of trimethylolpropane as a crosslinking agent were uniformly mixed. A pressure-sensitive adhesive composition was prepared.

  The pressure-sensitive adhesive composition was applied to a 38 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)) having a silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm. It was dried at 150 ° C. for 2 minutes and subjected to peroxide decomposition treatment, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel content of the pressure-sensitive adhesive layer was 69%, and the amount of peroxide decomposed was 7.56 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 2)
An optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 1 except that 0.30 part by weight of dibenzoyl peroxide was used instead of 0.15 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 82%, and the amount of peroxide decomposed was 11.74 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 3)
In Example 1, instead of using a polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)), a polyethylene terephthalate film (Mitsubishi Polyester, MRN38 (condensation reaction type silicone)) was used. An optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 1. The gel content of the pressure-sensitive adhesive layer was 70%, and the amount of peroxide decomposed was 7.50 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

Example 4
100 parts by weight of isooctyl acrylate, 1.0 part by weight of 2-hydroxybutyl acrylate, 0.10 part by weight of 2,2-azobisisobutyronitrile, and 200 parts by weight of ethyl acetate are provided with a nitrogen introduction tube and a cooling tube. The solution was charged into a four-necked flask, sufficiently purged with nitrogen, and then subjected to a polymerization reaction at 55 ° C. for 20 hours with stirring under a nitrogen stream to obtain a solution of a high molecular weight acrylic polymer B having a weight average molecular weight of 1,750,000. It was.

  Dibenzoyl peroxide (1 minute half-life: 130.0 ° C.) 0.15 parts by weight with respect to 100 parts by weight of the acrylic polymer B solution (solid content), 3-glycidoxypropyl as a silane coupling agent 0.10 parts by weight of trimethoxysilane and 0.10 parts by weight of an isocyanate-based crosslinking agent (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) consisting of a tolylene diisocyanate adduct of trimethylolpropane as a crosslinking agent were uniformly mixed. A pressure-sensitive adhesive composition was prepared.

  The pressure-sensitive adhesive composition was applied to a 38 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)) having a silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm. It was dried at 150 ° C. for 2 minutes and subjected to peroxide decomposition treatment, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel content of the pressure-sensitive adhesive layer was 79%, and the amount of peroxide decomposed was 8.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 5)
In Example 4, an optical member with an adhesive was prepared in the same manner as in Example 4 except that 0.30 part by weight of dibenzoyl peroxide was used instead of 0.15 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 83%, and the amount of peroxide decomposed was 12.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 6)
70 parts by weight of 2-ethylhexyl acrylate, 29 parts by weight of butyl acrylate, 1.0 part by weight of acrylic acid, 0.050 part by weight of 2,2-azobisisobutyronitrile and 200 parts by weight of ethyl acetate were added to a nitrogen inlet tube, After putting into a four-necked flask equipped with a cooling tube and sufficiently purging with nitrogen, a polymerization reaction is carried out at 55 ° C. for 20 hours with stirring under a nitrogen stream, and a high molecular weight acrylic polymer C having a weight average molecular weight of 1,460,000 is obtained. Solution was obtained.

  Dibenzoyl peroxide (1 minute half-life: 130.0 ° C.) 0.15 parts by weight with respect to 100 parts by weight of the acrylic polymer C solution (solid content), 3-glycidoxypropyl as a silane coupling agent 0.10 parts by weight of trimethoxysilane and 0.60 part by weight of an isocyanate-based crosslinking agent (coronate L, manufactured by Nippon Polyurethane Co., Ltd.) consisting of a tolylene diisocyanate adduct of trimethylolpropane as a crosslinking agent were uniformly mixed. A pressure-sensitive adhesive composition was prepared.

  The pressure-sensitive adhesive composition was applied to a 38 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)) having a silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm. It was dried at 150 ° C. for 2 minutes and subjected to peroxide decomposition treatment, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel content of the pressure-sensitive adhesive layer was 61%, and the amount of peroxide decomposed was 9.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 7)
In Example 6, an optical member with an adhesive was prepared in the same manner as in Example 6 except that 0.30 part by weight of dibenzoyl peroxide was used instead of 0.15 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 74%, and the amount of peroxide decomposed was 13.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 8)
70 parts by weight of 2-ethylhexyl acrylate, 30 parts by weight of butyl acrylate, 1.0 part by weight of acrylic acid, and 0.070 part by weight of 3-acryloxypropyltriethoxysilane were added to the reactive emulsifier Aqualon HS-10 (Daiichi Kogyo Seiyaku Co., Ltd.). In addition to 25 parts by weight of water to which 2.0 parts by weight were added, the mixture was emulsified with a homomixer to obtain an emulsion. Next, after putting into a four-necked flask equipped with a nitrogen introduction tube and a cooling tube and replacing with nitrogen for 1 hour, 30 parts by weight of water and 0.10 parts by weight of initiator VA-057 (manufactured by Wako Pure Chemical Industries, Ltd.) In addition, the above emulsion was then added dropwise over 4.5 hours while maintaining the reaction system at 59 ° C. to conduct a polymerization reaction. After completion of the reaction, ammonia was added to adjust the pH to 8, and an emulsion type acrylic polymer D solution was obtained.

  0.15 parts by weight of dibenzoyl peroxide (1 minute half-life: 130.0 ° C.) with respect to 100 parts by weight of the acrylic polymer D solution (solid content), 3-glycidoxypropyl as a silane coupling agent A pressure-sensitive adhesive composition was prepared by uniformly mixing 0.10 parts by weight of trimethoxysilane.

  The pressure-sensitive adhesive composition was applied to a 38 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)) having a silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm. It was dried at 150 ° C. for 2 minutes and subjected to peroxide decomposition treatment, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel content of the pressure-sensitive adhesive layer was 72%, and the amount of peroxide decomposed was 12.4 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

Example 9
0.15 parts by weight of di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life temperature: 92.1 ° C.) with respect to 100 parts by weight of the acrylic polymer A solution (solid content), silane Isocyanate-based cross-linking agent (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) consisting of 0.080 parts by weight of 3-glycidoxypropyltrimethoxysilane as a coupling agent and a tolylene diisocyanate adduct of trimethylolpropane as a cross-linking agent A pressure-sensitive adhesive composition was prepared by uniformly mixing 60 parts by weight.

  The pressure-sensitive adhesive composition was applied to a 38 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)) having a silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm. It was dried at 150 ° C. for 2 minutes and subjected to peroxide decomposition treatment, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel content of the pressure-sensitive adhesive layer was 81%, and the amount of peroxide decomposed was 8.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Example 10)
1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.) 0.30 parts by weight of silane based on 100 parts by weight of the acrylic polymer A solution (solid content) Isocyanate-based cross-linking agent (Coronate L, manufactured by Nippon Polyurethane Co., Ltd.) consisting of 0.075 parts by weight of 3-glycidoxypropyltrimethoxysilane as a coupling agent and a tolylene diisocyanate adduct of trimethylolpropane as a cross-linking agent A pressure-sensitive adhesive composition was prepared by uniformly mixing 60 parts by weight.

  The pressure-sensitive adhesive composition was applied to a 38 μm-thick polyethylene terephthalate film (manufactured by Mitsubishi Polyester, MRF38 (addition reaction type silicone)) having a silicone release treatment so that the dry thickness of the pressure-sensitive adhesive layer was 25 μm. It was dried at 150 ° C. for 2 minutes and subjected to peroxide decomposition treatment, transferred to a polarizing film, and used as an optical member with an adhesive of the present invention. The gel content of the pressure-sensitive adhesive layer was 72%, and the amount of peroxide decomposed was 5.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 1)
In Example 1, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 1 except that dibenzoyl peroxide was not added. The gel content of the pressure-sensitive adhesive layer was 62%.

(Comparative Example 2)
In Example 1, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 1 except that 0.60 part by weight of dibenzoyl peroxide was used instead of 0.15 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 88%, and the amount of peroxide decomposed was 22.2 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 3)
In Example 3, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 3 except that dibenzoyl peroxide was not added. The gel content of the pressure-sensitive adhesive layer was 59%.

(Comparative Example 4)
In Example 4, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 4 except that dibenzoyl peroxide was not added. The gel content of the pressure-sensitive adhesive layer was 75%.

(Comparative Example 5)
In Example 4, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 4 except that 0.60 part by weight of dibenzoyl peroxide was used instead of 0.15 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 79%, and the amount of peroxide decomposed was 24.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 6)
In Example 5, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 5 except that dibenzoyl peroxide was not added. The gel content of the pressure-sensitive adhesive layer was 60%.

(Comparative Example 7)
In Example 5, an optical member with an adhesive was prepared in the same manner as Example 5 except that 0.60 part by weight of dibenzoyl peroxide was used instead of 0.30 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 78%, and the amount of peroxide decomposed was 21.0 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 8)
In Example 8, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 8 except that dibenzoyl peroxide was not added. The gel content of the pressure-sensitive adhesive layer was 63%.

(Comparative Example 9)
In Example 8, an optical member with an adhesive was prepared in the same manner as in Example 8, except that 0.60 part by weight of dibenzoyl peroxide was used instead of 0.15 part by weight of dibenzoyl peroxide. The gel content of the pressure-sensitive adhesive layer was 78%, and the amount of peroxide decomposed was 23.1 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 10)
In Example 2, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 2 except that no silane coupling agent was added. The gel content of the pressure-sensitive adhesive layer was 82%, and the amount of peroxide decomposed was 11.74 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 11)
In Example 8, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 8 except that the silane coupling agent was not added. The gel content of the pressure-sensitive adhesive layer was 78%, and the amount of peroxide decomposed was 12.4 μmol with respect to 1 g of the pressure-sensitive adhesive composition.

(Comparative Example 12)
In Example 1, 0.30 part by weight of 2,2′-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd., azo initiator) was used instead of 0.15 part by weight of dibenzoyl peroxide. Except for the above, an optical member with a pressure-sensitive adhesive was produced in the same manner as in Example 8. The gel content of the pressure-sensitive adhesive layer was 72%.

  According to the said method, said evaluation of the produced optical member with an adhesive was performed. The obtained results are shown in Table 1.

  The compound types (peroxides and azo compounds) in Table 1 are as follows.

a) Peroxide P:
Dibenzoyl peroxide b) peroxide Q:
Di (4-t-butylcyclohexyl) peroxydicarbonate c) peroxide R:
1,1-di (t-hexylperoxy) cyclohexane d) Azo compound S:
2,2′-Azobisisobutyronitrile From the results in Table 1 above, in the step of forming the pressure-sensitive adhesive layer on the silicone release liner according to the production method of the present invention, the step of decomposing the peroxide on the release liner (Examples 1 to 10), in all Examples, the pressure-sensitive adhesive layer for an optical member, which is excellent in durability and the release force of the silicone release liner is easily adjusted to an appropriate release force, and an adhesive using the same An attached optical member could be obtained (see FIG. 1).

  On the other hand, in the case where the step of decomposing peroxide on the release liner was not included (Comparative Examples 1, 3 to 4, 6, 8, and 12), all of the release liners were excellent in durability. The peeling force was less than 0.1 N / 50 mm, and the adhesive force was insufficient. Further, when the peroxide decomposition amount is more than 20 μmol (Comparative Examples 2, 5, 7, 9), although the durability is excellent, the release force of the release liner is greater than 0.4 N / 50 mm in all cases. The peeling force became too large. On the other hand, when the silane coupling agent was not included (Comparative Examples 10 to 11), although it had an appropriate peeling force, it was a result that the durability was poor in any case.

  Therefore, it was confirmed that the pressure-sensitive adhesive layer for an optical member having excellent durability and appropriate peeling force and an optical member with a pressure-sensitive adhesive using the same were obtained by the method for producing a pressure-sensitive adhesive layer of the present invention.

Relationship diagram between peroxide decomposition amount and peeling force in Examples etc.

Claims (10)

  Release of a silicone release liner comprising a step of providing a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on a release-treated surface of a silicone release liner, and a step of thermally decomposing part or all of the peroxide Force adjustment method.   The method according to claim 1, wherein 1 to 20 µmol of the peroxide is thermally decomposed with respect to 1 g of the pressure-sensitive adhesive composition.   A method for producing a pressure-sensitive adhesive layer comprising a step of forming a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on a release-treated surface of a silicone release liner, comprising the step of adjusting the release force of a silicone release liner The manufacturing method of an adhesive layer with a silicone release liner.   The pressure-sensitive adhesive layer according to claim 3, wherein the pressure-sensitive adhesive composition contains, as a base polymer, a (meth) acrylic polymer having 80 parts by weight or more of a (meth) acrylic acid alkyl ester in 100 parts by weight of a monomer component. Production method.   The manufacturing method of the adhesive layer in any one of Claims 3-4 in which the said adhesive composition contains 0.01-1 weight part of silane coupling agents in 100 weight part of adhesive compositions. In the method for producing pressure-sensitive adhesive sheets with a silicone release liner, comprising a step of forming a layer of a pressure-sensitive adhesive composition containing a base polymer and a peroxide on a release-treated surface of a silicone release liner,
Method for producing pressure-sensitive adhesive sheets with a silicone release liner, wherein the release force of the silicone release liner is adjusted to be in the range of 0.1 to 0.4 N / 50 mm by the step of thermally decomposing part or all of the peroxide .   The adhesive layer for optical members manufactured by the method in any one of Claims 3-5.   The adhesive sheet for optical members which has the adhesive layer for optical members manufactured by the method in any one of Claims 3-5.   8. An optical member with an adhesive, wherein the optical member pressure-sensitive adhesive layer according to claim 7 is formed on one side or both sides of an optical member. An image display device using at least one optical member with an adhesive according to claim 9.

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