JP2008191309A - Optical laminate with pressure-sensitive adhesive layer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical laminate with a pressure-sensitive adhesive layer which excels in adhesiveness between the optical laminate and a glass substrate even under hot and humid conditions, avoids foam formation and peeling between the pressure-sensitive adhesive layer and the glass substrate, can suppress a void generation phenomenon caused by shrinkage of an optical film in the optical laminate, and is used for obtaining a liquid crystal display panel excellent in durability. <P>SOLUTION: The optical laminate with the pressure-sensitive adhesive layer is obtained by disposing a pressure-sensitive adhesive layer formed by crosslinking an aliphatic polyester resin (A) on an optical laminate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a protective film such as a cellulose triacetate film, an optical laminate provided with an adhesive layer for bonding an optical laminate coated with an optical film such as a polarizing film and a glass substrate of a liquid crystal cell, In particular, regarding the polarizing plate with the pressure-sensitive adhesive layer, more specifically, it has excellent adhesion between the optical laminate and the glass substrate even under conditions of high temperature and high humidity, and foaming or peeling between the pressure-sensitive adhesive layer and the glass substrate. In addition, the present invention relates to an optical laminate with an adhesive layer for obtaining a liquid crystal display panel having excellent durability, which can suppress white spots caused by shrinkage of an optical film.

Conventionally, a polarizing film, for example, a polarizing plate coated with a cellulose film, for example, a cellulose triacetate film, on both sides of a polarizing film, for example, a polyvinyl alcohol film having a polarizing property, is a liquid crystal component that is aligned between two glass plates. Lamination is performed on the surface of the sandwiched liquid crystal cell to form a liquid crystal display panel. This lamination to the liquid crystal cell surface is performed by pressing and pressing the adhesive layer provided on the polarizing plate surface against the cell surface. This is usually done by
The liquid crystal display panel obtained in this way is widely used as a display device for personal computers, liquid crystal televisions, car navigation systems, etc., and the use environment has become very harsh, and it is used in such harsh environments. However, it is required to have excellent durability.

  For example, in a severe environment such as high temperature and high humidity, a phenomenon such as foaming or peeling generated between the pressure-sensitive adhesive layer and the glass plate becomes a problem. In addition, the polarizing film shrinks in a high temperature and high humidity environment, whereas the pressure-sensitive adhesive layer cannot follow the shrinking of the polarizing film, and light leaks from the peripheral edge of the liquid crystal display panel. The so-called white spot phenomenon is a problem.

  As such countermeasures, various studies have been made on improving the composition of adhesives in acrylic adhesives that have been used conventionally. For example, 57 to 98.8 parts by weight of alkyl (meth) acrylate and 1 to 1 of functional group-containing monomers. 20 to 30 parts by weight, 0.2 to 3 parts by weight of a macromonomer having a (meth) acryloyl group, a glass transition temperature of 40 ° C. or higher, and a number average molecular weight in the range of 2000 to 20000, and at least the alkyl For a liquid crystal device comprising as a main component a copolymer of 0 to 20 parts by weight of another monomer copolymerizable with (meth) acrylate, and having a weight average molecular weight in the range of 500,000 to 2,000,000. A pressure-sensitive adhesive (for example, see Patent Document 1), (A) a (meth) acrylic acid ester homopolymer or copolymer having a weight average molecular weight of 500,000 to 2.5 million, B) a (meth) acrylic acid ester homopolymer or copolymer having a weight average molecular weight of 5,000 or more and less than 500,000 in a weight ratio of 100: 1 to 100: 50, and (A) component and (B) A pressure-sensitive adhesive composition in which at least one of the components is a (meth) acrylic acid ester copolymer having a nitrogen-containing functional group in the molecule (see, for example, Patent Document 2), (A) (meth) acrylic acid ester The content ratio of the bifunctional adduct body and the trifunctional or higher functional adduct body is 100: 0 to 10:90 in terms of weight ratio. A pressure-sensitive adhesive composition containing a crosslinking agent (see, for example, Patent Document 3), (A) a (meth) acrylic acid ester copolymer having a weight average molecular weight of 1,000,000 or more, and 100 parts by weight of (B) Heavy A pressure-sensitive adhesive composition comprising 5 to 100 parts by weight of a (meth) acrylic acid ester oligomer having an average molecular weight of 1,000 to 10,000 and 0.001 to 50 parts by weight of a crosslinking agent component containing (C) a bifunctional crosslinking agent. A thing (for example, refer patent document 4) etc. is proposed.

Japanese Unexamined Patent Publication No. Hei 8-209090 JP 2001-89731 A JP 2001-262103 A JP 2001-335767 A

However, in the disclosed technique of Patent Document 1, although foaming and peeling have been improved to some extent, the white spot phenomenon, which has been particularly emphasized in recent years, has not been considered, and is still satisfactory as a pressure-sensitive adhesive for polarizing plates. It wasn't going to be good.
Further, in the disclosed technique of Patent Document 2, peeling is improved, and although an effect is also observed for the white spot phenomenon, it is a durability evaluation under an environment of 65 ° C., 95% RH, 100 hours. It is not satisfactory and further improvement in durability is required.

  Furthermore, in the disclosed technologies of Patent Documents 3 and 4, foaming and peeling are further improved in the durability evaluation under the environment of 100 ° C., 1000 hours and 60 ° C., 90% RH, 1000 hours, and white spots are further improved. However, in consideration of the actual usage situation of the liquid crystal display panel, even in an environment where the temperature change is repeated in the range of room temperature to high temperature, there is a demand for a product that does not cause foaming, peeling, or white spots. Then it was still not satisfactory.

  On the other hand, as for the pressure-sensitive adhesive for polarizing plates, it is the current situation that studies on pressure-sensitive adhesives other than acrylic resins have not been sufficiently conducted. Particularly, polyester-based resins have a high glass transition temperature and crystallinity. Since there are many things to have, a polyester resin has not been used as an adhesive for polarizing plates until now.

  Therefore, in the present invention, under such a background, the polyester-based resin pressure-sensitive adhesive is used, and even under high-temperature and high-humidity conditions, the optical laminate, particularly, the adhesive between the polarizing plate and the glass substrate is excellent. Optical with pressure-sensitive adhesive layer for obtaining a liquid crystal display panel with excellent durability, which prevents foaming or peeling between the glass layer and the glass substrate, and suppresses white spots caused by contraction of the polarizing film. It aims at providing a laminated body, especially a polarizing plate with an adhesive layer.

However, as a result of intensive studies in view of such circumstances, the present inventors have used a polyester-based resin that has not been used as an adhesive for optical laminates for the pressure-sensitive adhesive layer, and further crosslinks the polyester-based resin. By using an aliphatic polyester-based resin, excellent adhesion between the optical laminate and the glass substrate, no foaming or peeling occurs between the adhesive layer and the glass substrate, white spots are suppressed, and durability The present invention was completed.
That is, the present invention provides an optical laminate with an adhesive layer, wherein an adhesive layer obtained by crosslinking a crosslinkable aliphatic polyester resin [I] is provided on the optical laminate. The gist.
Furthermore, a second gist of the present invention is a pressure-sensitive adhesive composition for an optical laminate comprising a crosslinkable aliphatic polyester resin [I] as a main component.
Heretofore, it has been thought that aliphatic polyester-based resins cannot provide sufficient durability because the resin itself is soft, and the present invention has found a surprising effect.

  The optical layered body with the pressure-sensitive adhesive layer of the present invention can be used under conditions of high temperature and high humidity by using an aliphatic polyester-based resin pressure-sensitive adhesive instead of the acrylic resin pressure-sensitive adhesive conventionally used as a pressure-sensitive adhesive for optical layered bodies. Even underneath, the adhesive between the optical laminate and the glass substrate is excellent, foaming and peeling do not occur between the adhesive and the glass substrate, and white spots caused by shrinkage of the optical film can be suppressed. Thus, a liquid crystal display panel having excellent durability can be obtained.

The present invention is described in detail below.
The optical layered body with the pressure-sensitive adhesive layer of the present invention is obtained by providing a pressure-sensitive adhesive layer obtained by crosslinking the crosslinkable aliphatic polyester resin [I] on the optical layered body.
The crosslinkable aliphatic polyester resin [I] used in the present invention is an aliphatic polyester resin containing a crosslinkable group and is not particularly limited as long as it is crosslinked by various crosslinking treatments. Absent. For example, in the case of crosslinking with a crosslinking agent as a crosslinking treatment, an aliphatic polyester resin containing a functional group capable of reacting with the crosslinking agent can be exemplified.

  The crosslinkable aliphatic polyester resin [I] in the present invention usually contains a hydroxyl group and / or a carboxyl group at the terminal and / or side chain of the main chain of the molecule. It contains an aliphatic polycarboxylic acid as a) and an aliphatic polyhydric alcohol as an alcohol component (b), and these are polycondensed.

  In addition, it is also possible to contain functional groups other than a hydroxyl group and / or a carboxyl group, and in that case, a compound having a functional group related to an acid component or an alcohol component may be used. Examples of such a functional group include a glycyl group, an isocyanate group, and an amide group.

The acid component (a) of the crosslinkable aliphatic polyester resin [I] in the present invention is not particularly limited as long as it is an aliphatic polyvalent carboxylic acid. For example, succinic acid, glutaric acid, adipic acid, azelain Saturated dicarboxylic acids such as acid, sebacic acid, decanedicarboxylic acid, and octadecanedicarboxylic acid, and unsaturated dicarboxylic acids such as fumaric acid, maleic acid, itaconic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, hexahydrophthalic acid, and dimer acids And aliphatic dicarboxylic acid (a1).
Among these, it is preferable to use a saturated dicarboxylic acid, and particularly from the viewpoint of effectively suppressing white spots occurring in the optical film, the number of carbon atoms is 2 to 20 (particularly preferably 4 to 15, more preferably 5 to 5). The saturated dicarboxylic acid of 10) is preferably used, adipic acid and sebacic acid are preferably used, and adipic acid is particularly preferably used.
These aliphatic carboxylic acids may be used alone or in combination of two or more.

  In the present invention, as the acid component (a), a trivalent or higher polyvalent carboxylic acid (a2) such as 1,2,4-butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, etc. It is preferable to use a polyvalent carboxylic acid or the like from the viewpoint of improving the crosslinking density and improving the durability.

  In the present invention, aromatic carboxylic acids such as terephthalic acid, isophthalic acid and 1,5-naphthalenedicarboxylic acid can be used as long as the effects of the present invention are not impaired. In order not to cause the phenomenon, it is better not to use an aromatic carboxylic acid.

The alcohol component (b) of the crosslinkable aliphatic polyester resin [I] in the present invention is not particularly limited as long as it is an aliphatic polyhydric alcohol.
For example, neopentyl glycol, 2-methyl-1,3-propanediol, 2-methyl-2-ethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2 -Propyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-methyl-2,4-pentanediol, 2,4 -Glycol (b1) having a hydrocarbon group in a side chain such as diethyl-1,5-pentanediol, 1,3,5-trimethyl-1,3-pentanediol, 2-methyl-1,6-hexanediol, Ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, , 8-octanediol, 1,9-nonanediol, linear aliphatic glycols such as 1,10-decanediol, polyethylene glycol, polypropylene glycol, polytetramethylene obtained by ring-opening polymerization of ethylene oxide, propion oxide, tetrahydrofuran, etc. And polyether diols such as glycol.

Among these, from the viewpoint of preventing crystallization, glycol (b1) having a hydrocarbon group in the side chain, particularly neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol is particularly used. It is preferable.
These aliphatic polyhydric alcohols may be used alone or in combination of two or more.

  In the present invention, as the alcohol component (b), a trihydric or higher polyhydric alcohol (b2) such as trimethylolethane, trimethylolpropane, glycerin, pentaerythritol, 1,2,4-butanetriol, 1, Use of 2,5-pentanetriol, 1,2,6-hexanetriol or the like is preferable from the viewpoint of improving the crosslinking density and improving the durability.

  In the present invention, the content ratio of the acid component (a) and the alcohol component (b) in the crosslinkable aliphatic polyester resin [I] preferably includes 1 to 2 equivalents of an alcohol component per equivalent of the acid component. It is more preferable to contain 1.2 to 1.7 equivalents. If the content of the alcohol component (b) is too small, the acid value tends to be high and it becomes difficult to increase the molecular weight, and if it is too much, the yield tends to decrease.

  In the crosslinkable aliphatic polyester resin [I] in the present invention, the crosslinkable aliphatic polyester resin [I] may contain 30 to 55 mol% of a structural site derived from the aliphatic dicarboxylic acid (a1). More preferably, it is more preferable to contain 40-50 mol%.

Further, in the crosslinkable aliphatic polyester resin [I] in the present invention, a structural site derived from glycol (b1) having a hydrocarbon group in the side chain is added in the crosslinkable aliphatic polyester resin [I] in an amount of 5 to 50. It is preferable to contain mol%, and it is more preferable to contain 10-45 mol%.
If the content is too small, crystallization occurs and it tends to be difficult to bond the optical film to the glass substrate. If the content is too large, it tends to be difficult to obtain a high molecular weight aliphatic polyester resin.

  Furthermore, in the present invention, a structural site derived from a trihydric or higher polyhydric alcohol component and / or a trivalent or higher polyvalent carboxylic acid component is added in an amount of 0.01 to 1 mol% in the crosslinkable aliphatic polyester resin [I]. It is preferable to contain from the point which improves a gel fraction and improves durability.

  The crosslinkable aliphatic polyester resin [I] used in the present invention can be obtained by subjecting an acid component (a) and an alcohol component (b) to a polycondensation reaction by a known method in the presence of a catalyst.

In the polycondensation reaction, an esterification reaction is first performed, and then a condensation reaction is performed.
In such esterification reaction, a catalyst is used. Specifically, titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, antimony-based compounds such as antimony trioxide, germanium-based catalysts such as germanium oxide, zinc acetate, Examples thereof include manganese acetate and dibutyltin oxide, and one or more of these are used. Among these, tetrabutyl titanate is preferable from the viewpoint of high catalyst activity, and acid value germanium is preferable from the viewpoint of avoiding coloring.

  The blending amount of the catalyst is preferably 1 to 10,000 ppm, more preferably 10 to 5000 ppm, and still more preferably 10 to 3000 ppm with respect to all copolymer components. If the blending amount is too small, the polymerization reaction tends not to proceed sufficiently. If the blending amount is too large, there is no advantage such as shortening the reaction time, and side reactions tend to occur.

About the temperature at the time of esterification, 160-260 degreeC is preferable, 180-250 degreeC is more preferable, 200-250 degreeC is further more preferable. If the temperature is too low, the reaction tends not to proceed sufficiently, and if it is too high, side reactions such as decomposition tend to occur.
The pressure during the esterification reaction is usually preferably a normal pressure.

  After the esterification reaction has been carried out, a condensation reaction is then carried out. The conditions at this time are such that a catalyst similar to the above esterification reaction is further added in an equivalent amount, and the reaction temperature is preferably 220. It is preferable that the reaction system is gradually reduced in pressure to ˜260 ° C., more preferably 230 to 250 ° C., and the reaction is finally carried out at 5 hPa or less. If the reaction temperature is too low, the reaction tends not to proceed sufficiently. Conversely, if the reaction temperature is too high, side reactions such as decomposition tend to occur.

  The number average molecular weight of the crosslinkable aliphatic polyester resin [I] used in the present invention is preferably 5,000 or more, particularly preferably 10,000 or more, and further preferably 20,000 or more. If the number average molecular weight is too small, sufficient cohesive force as an adhesive cannot be obtained, and heat resistance and mechanical strength tend to be lowered. In addition, the upper limit of the number average molecular weight is usually 100,000.

  The weight average molecular weight of the crosslinkable aliphatic polyester resin [I] used in the present invention is preferably 10,000 or more, particularly preferably 20,000 or more, and further preferably 50,000 or more. When the weight average molecular weight is too small, sufficient cohesive force as an adhesive cannot be obtained, and heat resistance and mechanical strength tend to be lowered. The upper limit of the weight average molecular weight is usually 500,000.

The degree of dispersion (weight average molecular weight / number average molecular weight) of the crosslinkable aliphatic polyester resin [I] used in the present invention is not particularly limited, but is preferably 2 or more, and is 2.2 to 10. It is more preferable. The upper limit of the degree of dispersion is usually 20. If the degree of dispersion is too low, the durability tends to decrease, and if it is too high, gelation tends to occur and the durability tends to decrease. The degree of dispersion is determined by the content of the trivalent or higher polyvalent carboxylic acid and / or the trihydric or higher polyhydric alcohol for constituting the crosslinkable aliphatic polyester resin [I], and the condensation reaction conditions (temperature, The degree of vacuum, stirring, reaction time, etc.) can be adjusted.
For example, when the content ratio of a trivalent or higher polyvalent carboxylic acid and / or a trivalent or higher polyhydric alcohol for constituting the crosslinkable aliphatic polyester resin [I] is increased, the degree of dispersion tends to increase. In addition, in the condensation reaction, the degree of dispersion is increased by increasing the temperature and the degree of vacuum or extending the reaction time.

  The glass transition temperature of the crosslinkable aliphatic polyester resin [I] used in the present invention is preferably −10 ° C. or lower, and more preferably −20 ° C. or lower. The lower limit of the glass transition temperature is usually preferably -80 ° C, and more preferably -70 ° C. If the temperature is too high, the flexibility is lost and the optical film tends to be peeled off from the glass substrate. If the temperature is too low, the optical film tends to cause white spots.

The crosslinkable aliphatic polyester resin [I] used in the present invention is preferably one that does not crystallize, and even if crystallization occurs, the crystallization temperature is 0 ° C. or lower, particularly −30 ° C. or lower. preferable. If the temperature is too high, the optical film tends to be peeled off from the glass substrate.
Also, the crystallization energy is preferably as low as possible, preferably 35 J / g or less, particularly 20 J / g or less, more preferably 15 J / g or less. If this energy is too large, the optical film tends to be peeled off from the glass substrate.

  In the present invention, the above-mentioned crosslinkable aliphatic polyester resin [I] is preferably an aliphatic polyester resin having a functional group capable of reacting with a crosslinker [II] described later, and the pressure-sensitive adhesive layer also. The aliphatic polyester resin is preferably crosslinked with a crosslinking agent [II].

  The crosslinking agent [II] may be any compound having a functional group that reacts with the functional group contained in the crosslinkable aliphatic polyester resin [I]. Examples thereof include polyisocyanate compounds and polyepoxy compounds. Can be mentioned. Among these, a polyisocyanate compound is preferable from the viewpoint that both the durability and the point of effectively suppressing the white spot phenomenon of the optical film can be achieved in a balanced manner.

  Examples of such polyisocyanate compounds include tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, and hydrogenated xylylene diisocyanate, and trimethylolpropane. And polyisocyanate isocyanate adducts such as tolylene diisocyanate adduct, hexamethylene diisocyanate adduct and isophorone diisocyanate adduct.

In addition, as this polyisocyanate type compound, the thing by which the isocyanate part was blocked by phenol, lactam, etc. can also be used.
Moreover, these crosslinking agents [II] may be used independently and may be used together 2 or more types.

  The amount of the crosslinking agent [II] used can be appropriately selected depending on the molecular weight of the crosslinkable aliphatic polyester resin [I] and the purpose of use, but usually the functional group contained in the crosslinkable aliphatic polyester resin [I]. It is preferable that the reactive group contained in the crosslinking agent [II] contains 0.2 to 10 equivalents of the crosslinking agent with respect to 1 equivalent, and more preferably 0.8 to 8 equivalents. 1 to 5 equivalents are more preferable. When the number of equivalents of the reactive group contained in the crosslinking agent [II] is too small, the cohesive force tends to be insufficient and sufficient durability tends not to be obtained. It tends to be difficult to match.

  In the present invention, the crosslinking agent [II] is blended with the crosslinkable aliphatic polyester resin [I], and the crosslinking is carried out. After chain extension with isocyanate, crosslinking with an isocyanate adduct of a polyhydric alcohol is preferable in terms of effectively suppressing white spots due to film shrinkage and improving heat resistance.

  In the present invention, it is also preferable that the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer contains the silane compound [III] from the viewpoint of improving the adhesion to the optical laminate. About content, 0.001-10 weight part with respect to 100 weight part of crosslinkable aliphatic polyester-type resin [I], Especially 0.01-1 weight part, Furthermore, 0.03-0.8 weight. Part. If the content is too small, the effect of addition tends not to be obtained, and if the content is too large, the compatibility with the crosslinkable aliphatic polyester resin [I] tends to be poor and adhesive strength and cohesive strength tend not to be obtained.

  The silane compound [III] is not particularly limited, and examples thereof include epoxy silane, acrylic silane, mercapto silane, and hydroxyl silane. Among these, an epoxy silane compound is particularly preferably used.

  Specific examples of such epoxy silane compounds include, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and γ-glycidoxypropyl. Examples include methyldimethoxysilane, methyltri (glycidyl) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like, among which γ-glycid Xylpropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β- (3,4 epoxycyclohexyl) ethyltrimethoxysilane are preferred.

  In the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer in the present invention, other pressure-sensitive adhesives, urethane resins, rosins, rosin esters, hydrogenated rosin esters, phenol resins, aromatic modifications are within the range not impairing the effects of the present invention. A tackifier such as a terpene resin, an aliphatic petroleum resin, an alicyclic petroleum resin, a styrene resin, or a xylene resin, or a known additive can be added.

  Thus, in the present invention, the pressure-sensitive adhesive layer is obtained by crosslinking the pressure-sensitive adhesive composition containing the crosslinkable aliphatic polyester resin [I], preferably the crosslinker [II], more preferably the silane compound [III]. Is provided on the optical laminate to obtain an optical laminate with a pressure-sensitive adhesive layer. In the optical laminate with a pressure-sensitive adhesive layer, a release sheet is further provided on the surface opposite to the optical laminate of the pressure-sensitive adhesive layer. Is preferably provided.

  Although it does not specifically limit as a manufacturing method of this optical laminated body with an adhesive layer, (1) After apply | coating an adhesive composition on an optical laminated body and drying, it pastes a release sheet further. It is preferable to manufacture by the method or (2) the method of sticking an optical laminated body after apply | coating and drying an adhesive composition on a release sheet, and peeling off this release sheet when using for a practical use. Used.

  In such coating, it is preferable to dilute and apply in a solvent, and the dilution concentration is preferably 20 to 50% by weight, particularly preferably 25 to 40% by weight. The solvent is not particularly limited as long as it dissolves the crosslinkable aliphatic polyester resin [I], the crosslinking agent [II], and the silane compound [III]. For example, methyl acetate, ethyl acetate, Ester solvents such as methyl acetoacetate and ethyl acetoacetate, ketone solvents such as acetone and methyl isobutyl ketone, and aromatic solvents such as toluene and xylene can be used. Among these, ethyl acetate is preferably used from the viewpoints of solubility, drying property, price, and the like.

  The gel fraction of the pressure-sensitive adhesive layer produced by the above method is preferably 70% or more from the viewpoint of durability and white spots resistance, and particularly preferably 80% or more. If the gel fraction is too low, durability and white spots due to insufficient cohesive force tend to deteriorate. The upper limit of the normal gel fraction is 100%.

  Moreover, although the thickness of the adhesive layer obtained is not specifically limited, 10-40 micrometers is preferable and 20-30 micrometers is especially preferable. If the thickness is too thin, the adhesive physical properties tend to be difficult to stabilize, and if it is too thick, adhesive residue tends to occur.

  Since the optical layered body with the pressure-sensitive adhesive layer of the present invention has a release sheet directly or after peeling off the release sheet, the surface of the pressure-sensitive adhesive layer is bonded to a glass substrate and used for, for example, a liquid crystal display board. is there.

  The optical laminate in the present invention is not particularly limited, and examples thereof include a polarizing plate, a retardation plate, an elliptically polarizing plate, an optical compensation film, a brightness enhancement film, and those in which these are laminated. However, the polarizing plate is particularly effective in the present invention.

  The polarizing plate used in the present invention is usually obtained by laminating a cellulose triacetate film as a protective film on both sides of a polarizing film, and the polarizing film has an average polymerization degree of 1,500 to 10,000, saponification. A uniaxially stretched film dyed with an aqueous solution of iodine-potassium iodide or a dichroic dye (2 to 10 times, preferably 3 A draw ratio of about 7 times) is used.

  Polyvinyl alcohol resins are usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, but small amounts of unsaturated carboxylic acids (including salts, esters, amides, nitriles, etc.), olefins, vinyl ethers, A component copolymerizable with vinyl acetate, such as a saturated sulfonate, may be contained. Moreover, what is called polyvinyl acetal resin and polyvinyl alcohol derivatives, such as polybutyral resin, polyvinyl formal resin, etc. which reacted polyvinyl alcohol with aldehydes in presence of an acid is mentioned.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further more concretely, this invention is not limited to a following example, unless the summary is exceeded.
In the examples, “parts” and “%” mean weight basis unless otherwise specified.
The methods for measuring glass transition temperature, crystallinity, crystallization energy, number average molecular weight, weight average molecular weight, and degree of dispersion are as follows.

<Glass transition temperature>
The test piece is heated and cooled at a rate of 10 ° C./min from room temperature, the calorific value is measured with a differential scanning calorimeter, two extension lines are drawn on the endothermic curve or exothermic curve, and 1 between the extension lines. The temperature at the intersection of the / 2 line and the endothermic curve or exothermic curve was taken as the glass transition temperature.

<Crystallinity>
The test piece was heated and cooled from room temperature at a rate of 10 ° C./min, the calorific value was measured with a differential scanning calorimeter, and the top of the exothermic peak was taken as the crystallization temperature.

<Crystalization energy>
The test piece was heated and cooled from room temperature at a rate of 10 ° C./min, the calorific value was measured with a differential scanning calorimeter, and the area of the exothermic peak was calculated.

<Number average molecular weight, weight average molecular weight>
The weight average molecular weight and the number average molecular weight are average molecular weights in terms of standard polystyrene molecular weight, and are used in high performance liquid chromatography (manufactured by Nippon Waters Co., Ltd., “Waters 2695 (separation module)” and “Waters 2414 (detector)”). Column: Shodex GPC KF-806L (exclusion limit molecular weight: 2 × 10 ⁷ , separation range: 100 to 2 × 10 ⁷ , theoretical plate number: 10,000 plates / pack, filler material: styrene-divinylbenzene copolymer, The particle size was measured by using three filler particles having a particle diameter of 10 μm.
<Dispersity>
It was calculated from the weight average molecular weight and the number average molecular weight.

[Example 1]
In a four-necked separable flask equipped with a thermometer, stirrer, distillation tube and condenser, 201.7 g (1.0 mol) of sebacic acid, 143.9 g of 2-butyl-2-ethyl-1,3-propanediol (0.90 mol), 1,4-butanediol 53.0 g (0.59 mol), trimethylolpropane 1.3 g (0.0097 mol) and tetra-n-butyl titanate 0.15 g were charged, The esterification reaction was carried out by heating at 260 ° C. for 150 minutes, then the pressure in the reaction system was gradually reduced to 133 Pa after 10 minutes, and the reaction was further continued for 240 minutes while continuing to reduce the pressure, to obtain aliphatic polyester resin [I-1] Got.
The resulting aliphatic polyester resin [I-1] has a number average molecular weight of 46,000, a weight average molecular weight of 135,000, a dispersity of 2.9, a glass transition temperature of −50 ° C. or less, and crystallization. It was not something.
This aliphatic polyester resin [I-1] was charged into a four-necked separable flask equipped with a thermometer, a stirrer, and a reflux condenser, dissolved in ethyl acetate, and then isophorone diisocyanate was added to the aliphatic polyester resin [I- 1] 1.4 parts per 100 parts (solid content) and 0.3 parts of dibutyltin dilaurate were charged and reacted at 75 ° C. for 15 hours to give a polyester resin-based polyurethane resin ethyl acetate solution having a resin content of 35% [I- 1 ′] was obtained.
This 35% polyester resin-based polyurethane resin ethyl acetate solution [I-1 ′] was mixed with a 55% ethyl acetate solution of tolylene diisocyanate adduct of trimethylolpropane as a cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., “Coronate L”). 5.6 parts of -55E ") and 0.035 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co.," KBM403 ") as a silane compound were added and mixed. Thereafter, it was applied to a polyester release sheet so that the thickness after drying was 25 μm, dried at 100 ° C. for 3 minutes, transferred onto a polarizing plate (thickness 190 μm), and subjected to 4 under conditions of 40 ° C. and dry. The film was aged for a day to obtain a polarizing plate with an adhesive layer.

[Example 2]
In a four-necked separable flask equipped with a thermometer, stirrer, distillation tube, and condenser, 126.5 g (0.63 mol) of sebacic acid, PTXG-1800 (polyether glycol of tetrahydrofuran and neopentyl glycol: Asahi Kasei) Fiber: hydroxyl value 62.34) 202.6 g (0.11 mol), neopentyl glycol 46.9 g (0.45 mol), ethylene glycol 22.7 g (0.37 mol), trimethylolpropane 1.3 g (0.0097 mol) and 0.15 g of tetra-n-butyl titanate were added, heated at 150 to 260 ° C. for 150 minutes to carry out an esterification reaction, and then the pressure of the reaction system was gradually reduced to 133 Pa after 10 minutes. The reaction was further continued for 90 minutes while continuing to reduce the pressure to obtain an aliphatic polyester resin [I-2].
The resulting aliphatic polyester resin [I-2] had a number average molecular weight of 18,000, a weight average molecular weight of 75,000, a degree of dispersion of 4.2, a glass transition temperature of −50 ° C. or less, and crystallization. It was not something.
This aliphatic polyester resin was charged into a four-necked separable flask equipped with a thermometer, a stirrer, and a reflux condenser, dissolved in ethyl acetate, and then isophorone diisocyanate was added to 100 parts of aliphatic polyester resin [I-2] ( 1.4 parts of solid content) and 0.3 parts of dibutyltin dilaurate were further added and reacted at 75 ° C. for 15 hours to obtain a polyurethane resin ethyl acetate solution [I-2 ′] based on a polyester resin of 30% polyester resin. .
Polyester resin-based polyurethane resin ethyl acetate solution [I-2 ′] having a resin content of 30% was mixed with a 55% ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane as a cross-linking agent (“Coronate L As a silane compound, γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM403”) was added in an amount of 0.030 part and mixed. Thereafter, it was applied to a polyester release sheet so that the thickness after drying was 25 μm, dried at 100 ° C. for 3 minutes, transferred onto a polarizing plate (thickness 190 μm), and subjected to conditions of 40 ° C. and dry. Aging was performed for 4 days to obtain a polarizing plate with an adhesive layer.

[Example 3]
In a four-necked separable flask equipped with a thermometer, a stirrer, a distillation tube and a condenser, 220.7 g (1.51 mol) of adipic acid, 94.4 g (0.91 mol) of neopentyl glycol, 83. 9 g (1.35 mol), trimethylolpropane 1.0 g (0.0074 mol), and germanium oxide 0.10 g were charged and heated at 150 to 260 ° C. for 150 minutes for esterification, and then the pressure of the reaction system Was gradually reduced to 133 Pa after 10 minutes, and the reaction was further continued for 300 minutes while continuing to reduce the pressure to obtain an aliphatic polyester resin [I-3].
The resulting aliphatic polyester resin [I-3] has a number average molecular weight of 44,000, a weight average molecular weight of 113,000, a dispersity of 2.6, a glass transition temperature of −43 ° C., and does not crystallize. It was a thing.
After dissolving this aliphatic polyester resin [I-3] with ethyl acetate so that the resin content is 45%, a 55% ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane as a crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., As a silane compound, 7.2 parts of “Coronate L-55E”) and 0.045 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM403”) were added and mixed. Thereafter, it was applied to a polyester release sheet so that the thickness after drying was 25 μm, dried at 100 ° C. for 3 minutes, transferred onto a polarizing plate (thickness 190 μm), and subjected to conditions of 40 ° C. and dry. Aging was performed for 4 days to obtain a polarizing plate with an adhesive layer.

[Example 4]
The aliphatic polyester resin [I-3] obtained in Example 3 was charged into a four-necked separable flask equipped with a thermometer, a stirrer, and a reflux condenser, dissolved in ethyl acetate, and then isophorone diisocyanate was added to the polyester. Preparation of 1.4 parts of 100 parts of resin (solid content), 0.3 parts of dibutyltin dilaurate, and reaction at 75 ° C. for 15 hours, polyurethane resin ethyl acetate solution based on polyester resin with 30% resin content [I-3 '] Got.
A 55% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct as a crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., “Coronate L”) was used as a crosslinking agent. -55E ") 4.8 parts and 0.030 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.," KBM403 ") as a silane compound was added and mixed. Thereafter, it was applied to a polyester release sheet so that the thickness after drying was 25 μm, dried at 100 ° C. for 3 minutes, transferred onto a polarizing plate (thickness 190 μm), and subjected to conditions of 40 ° C. and dry. Aging was performed for 4 days to obtain a polarizing plate with an adhesive layer.

[Comparative Example 1]
A four-necked round bottom flask was equipped with a reflux condenser, a stirrer, a dropping funnel and a thermometer. 94 parts of n-butyl acrylate, 5 parts of methyl acrylate, 1 part of acrylic acid, 80 parts of ethyl acetate, 45 parts of acetone, polymerization As an initiator, 0.03 part of azobisisobutyronitrile was charged, and the temperature in the reaction vessel was raised to 70 ° C. and reacted for 2 hours. Then, 0.03 parts of azobisisobutyronitrile dissolved in 80 parts of ethyl acetate was added and reacted for 2 hours, and further 0.03 parts of azobisisobutyronitrile was dissolved in 80 parts of ethyl acetate. And reacted for 3 hours. After completion of the reaction, the mixture was diluted with ethyl acetate and toluene (weight mixing ratio of ethyl acetate and toluene = 50: 50) to give a resin content of 19% and a weight average molecular weight of 1,650,000 (the ratio of each designated molecular weight was 100 An acrylic resin solution having a dispersity of 8 and a glass transition temperature of −50 ° C. was obtained with 55% over 10,000, 17% between 500,000 and 1,000,000, 15% between 100,000 and 500,000, and 13% below 100,000. .
0.19 parts of a 55% ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane (Nippon Polyurethane Co., Ltd., “Coronate L-55E”) as a crosslinking agent in an acrylic resin solution having a resin content of 19%, silane As a compound, 0.019 part of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM403”) is added and mixed, and then the polyester release sheet is dried to a thickness of 25 μm. It was applied and dried at 100 ° C. for 3 minutes. Then, it was transferred onto a polarizing plate (thickness 190 μm) and aged for 7 days under conditions of 23 ° C. and 50% RH to obtain a polarizing plate with an adhesive layer.

[Comparative Example 2]
In a four-necked separable flask equipped with a thermometer, stirrer, distillation tube and condenser, isophthalic acid 38.4 g (0.23 mol) sebacic acid 187.1 g (0.93 mol), neopentyl glycol 108.4 g (1.04 mol), 1,4-butanediol 52.1 g (0.58 mol), 1,6-hexanediol 11.9 g (0.10 mol), trimethylolpropane 2.0 g (0.015 mol) ) And tetra-n-butyl titanate (0.15 g), heated at 150 to 260 ° C. for 120 minutes to carry out the esterification reaction, and then gradually reduced the pressure of the reaction system to 133 Pa after 10 minutes, and further reduced pressure Then, the reaction was carried out for 120 minutes to obtain an aromatic-containing polyester resin.
The obtained aromatic-containing polyester resin had a number average molecular weight of 30,000, a dispersity of 2.8, a glass transition temperature of −50 ° C., and was not crystallized.
The aromatic polyester resin was charged into a four-necked separable flask equipped with a thermometer, a stirrer, and a reflux condenser, dissolved in ethyl acetate, and then isophorone diisocyanate was added to 100 parts of polyester resin (solid content). .4 parts and 0.3 parts of dibutyltin dilaurate were added and reacted at 75.degree. C. for 15 hours to obtain a polyester resin-based polyurethane resin ethyl acetate solution having a resin content of 35%.
Polyester resin-based polyurethane resin ethyl acetate solution having a resin content of 35% and 5% ethyl acetate solution of trimethylolpropane tolylene diisocyanate adduct as a cross-linking agent (“Coronate L-55E” manufactured by Nippon Polyurethane Co., Ltd.) .6 parts, 0.0035 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM403”) as a silane compound, mixed, and then dried on a polyester release sheet. Was applied to a thickness of 25 μm and dried at 100 ° C. for 3 minutes. Then, it was transferred onto a polarizing plate (thickness 190 μm) and aged for 4 days under conditions of 40 ° C. and dry to obtain a polarizing plate with an adhesive layer.

  Moreover, the sample for gel fractions was obtained by the method similar to the above using the polyethylene terephthalate film (thickness 38 micrometers) instead of the polarizing plate. After cutting the obtained sample to 40 × 40 mm, the release sheet is peeled off and the pressure-sensitive adhesive layer side is bonded to a 50 × 100 mm SUS mesh sheet (200 mesh), and then to the longitudinal direction of the SUS mesh sheet. The sample was wrapped from the center and wrapped in a sample, and then the gel fraction was measured by the change in weight when immersed in a sealed container containing 250 g of toluene.

  The polarizing plate was laminated with a cellulose triacetate film having a thickness of 80 μm on both sides of a 30 μm-thick polyvinyl alcohol polarizing film (average polymerization degree 1700, average saponification degree 99 mol%, iodine staining, 4-fold stretching). A polarizing plate (a polyvinyl alcohol polarizing film was cut at 233 mm × 309 mm by tilting the stretching axis direction by 45 degrees: equivalent to 15 inches) was used.

  Next, the release sheet of the polarizing plate with the pressure-sensitive adhesive layer obtained in Examples 1 to 4 and Comparative Examples 1 and 2 was peeled off, and the pressure-sensitive adhesive layer side was made of an alkali-free glass plate (Corning, “Corning 1737”). )), And after laminating the polarizing plate and the glass plate, autoclave treatment (50 ° C., 0.5 MPa, 20 minutes) is performed, and then foaming, peeling, and blanking phenomenon in the following durability test are performed. Evaluation was performed. The evaluation criteria are as follows.

〔An endurance test〕
(1) Heat test 90 ° C, 500 hours durability test (2) Moisture and heat resistance test 60 ° C, 90% RH, 500 hours durability test (3) Temperature change repetition test After leaving at -30 ° C for 30 minutes, at 70 ° C Endurance test for 300 cycles, with 30 minutes of operation as one cycle

〔Evaluation criteria〕
(Foam)
○: No foaming is observed Δ: Foaming with a diameter of less than 100 μm is slightly observed ×: Foaming with a diameter of 100 μm or more is often observed (peeling)
○ ・ ・ ・ No peeling △ ・ ・ ・ Peeling less than 1mm or floating streaks × ・ ・ ・ Peeling more than 1mm (white spots)
○… No white spots are seen △… White spots are slightly generated × ・ ・ ・ White spots are largely generated on the four sides

The charge composition ratios of the pressure-sensitive adhesive layer compositions of Examples and Comparative Examples are summarized in Table 1.
Table 2 shows the evaluation results obtained according to the above evaluation method.

(*1) ｎ−ブチルアクリレート：メチルアクリレート：アクリル酸
＝９４：５：１（重量比）

(* 1) n-butyl acrylate: methyl acrylate: acrylic acid = 94: 5: 1 (weight ratio)

In Examples 1 to 4 using a crosslinkable aliphatic polyester resin in the pressure-sensitive adhesive composition, Example 4 in which adipic acid was used as an acid component and chain extension was performed was foaming and peeling in any item in the durability test. It was found that this was very useful for obtaining a liquid crystal display panel having no durability and no white spots.
In addition, regarding Examples 1 and 2 using sebacic acid as the acid component and Example 3 using adipic acid but not performing chain extension, foaming, peeling, and white spots were slightly observed in the heat test. However, it was a level which can be used industrially as an adhesive for optical members.
In Comparative Example 1 in which an acrylic resin was used for the pressure-sensitive adhesive composition, slight foaming, peeling, and white spots were observed in the heat resistance test. Further, in the temperature change repeatability test, many foams were observed, and an effect of a level sufficient for use in optical member applications was not obtained.
In Comparative Example 2 where an aromatic-containing polyester resin was used for the pressure-sensitive adhesive composition, foaming and peeling did not occur in any item in the durability test. However, large white spots occurred on the four sides, and a sufficient level of effect for use in optical member applications could not be obtained.

  The present invention has excellent adhesion between the optical laminate and the glass substrate even under high temperature and high humidity conditions, and does not cause foaming or peeling between the pressure-sensitive adhesive layer and the glass substrate. Therefore, it is very useful for obtaining a liquid crystal display panel having excellent durability.

Claims (12)

  An optical laminate with an adhesive layer, wherein an adhesive layer obtained by crosslinking a crosslinkable aliphatic polyester resin [I] is provided on the optical laminate.   The optical laminate with an adhesive layer according to claim 1, wherein the adhesive layer is an adhesive layer obtained by crosslinking the crosslinkable aliphatic polyester resin [I] with the crosslinking agent [II].   The optical laminated body with an adhesive layer according to claim 1 or 2, wherein the crosslinkable aliphatic polyester resin [I] is an aliphatic polyester resin having a functional group capable of reacting with the crosslinking agent [II].   The crosslinkable aliphatic polyester-based resin [I] contains an aliphatic dicarboxylic acid (a1) having 2 to 20 carbon atoms as the acid component (a). Laminated body.   The optical laminate with an adhesive layer according to any one of claims 1 to 4, wherein the crosslinkable aliphatic polyester resin [I] contains a glycol (b1) having a hydrocarbon group in the side chain as an alcohol component (b). body.   The crosslinkable aliphatic polyester resin [I] contains a trivalent or higher polyvalent carboxylic acid (a2) as the acid component (a) and / or a trihydric or higher polyhydric alcohol (b2) as the alcohol component (b). The optical laminated body with an adhesive layer in any one of Claims 1-5 formed.   The number average molecular weight of crosslinkable aliphatic polyester-type resin [I] is 5,000 or more, The optical laminated body with an adhesive layer in any one of Claims 1-6.   The optical laminated body with an adhesive layer according to any one of claims 1 to 7, wherein the crosslinkable aliphatic polyester resin [I] is cross-linked after being chain-extended with polyisocyanate.   The optical laminated body with an adhesive layer in any one of Claims 1-8 in which the adhesive composition which forms an adhesive layer contains silane type compound [III] further.   The optical layered product with an adhesive layer according to any one of claims 1 to 9, wherein a gel fraction of the adhesive layer is 70% or more.   The optical laminated body is a polarizing plate, The optical laminated body with an adhesive layer in any one of Claims 1-10.   A pressure-sensitive adhesive composition for an optical laminate, comprising a crosslinkable aliphatic polyester resin [I] as a main component.