JP2015193711A - Adhesive composition, adhesive polarizing plate, and liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition that achieves both of initial reworkability and high adhesive force under the condition of high temperature or high temperature and high humidity, by compounding a silane coupling agent having such a structure that a connecting chain between an epoxy group and a hydrolyzable silyl group has a specific chain length, as an essential component of an adhesion modifier.SOLUTION: The adhesive composition comprises (A) an acrylic polymer and (B) an adhesion modifier comprising an epoxy group-containing organic silicon compound represented by general formula (1) and/or its partially hydrolyzed product or partially hydrolyzed condensate, in which with respect to 100 parts by mass of (A) component, (B) component is included by 0.001 to 10 parts by mass. In formula (1), X represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R represents a monovalent hydrocarbon group having 1 to 6 carbon atoms; A represents a divalent hydrocarbon group having 6 to 10 carbon atoms; Y represents an epoxy structure group; and n is an integer of 1 to 3.

Description

  The present invention relates to a pressure-sensitive adhesive composition using a novel adhesion modifier, and more specifically, a silane coupling agent having a structure in which a connecting chain of an epoxy group and a hydrolyzable silyl group has a specific chain length. By using it, the proportion of the organic part increases compared to the silane coupling agent used in the existing technology, as a result, the compatibility with the resin is improved and the bonding strength with the matrix resin having a hydroxyl group, Adhesive composition that can improve the initial reworkability dramatically because it has excellent interaction, and the adhesion between the adhesive containing the matrix resin and the substrate is improved, and the hydrolyzability of the silyl group is low. The present invention relates to an adhesive polarizing plate having an adhesive layer formed from the adhesive composition and a liquid crystal display device including the adhesive polarizing plate.

  Silane coupling agents have two or more different functional groups in the molecule and act as an intermediary for linking organic materials and inorganic materials that are usually difficult to bond. One of the functional groups is a hydrolyzable silyl group, and a silanol group is generated in the presence of water, and this silanol group reacts with a hydroxyl group on the surface of the inorganic material to form a chemical bond with the surface of the inorganic material. Other functional groups are organic reactive groups such as vinyl groups, epoxy groups, amino groups, (meth) acrylic groups, and mercapto groups that form chemical bonds with organic materials such as various synthetic resins. Using such properties, they are widely used as organic / inorganic resin modifiers, adhesion aids, various additives, and the like.

  Among the applications of silane coupling agents, the use of adhesives as adhesive modifiers is a typical example. For example, an adhesive used for attaching a liquid crystal cell and an optical film is a liquid crystal display device (LCD). ), The required bonding performance has become sophisticated.

  In the case of LCD, unlike the initial expectation that it is difficult to increase the size of 20 inches or more, the size is rapidly increasing. Major manufacturers have so far focused on the production of small panels of 20 inches or less, but in response to recent trends, they have actively introduced the latest technology and expanded the product range to large sizes of 20 inches or more. .

  Thus, in various optical films, the glass used at the time of manufacturing a liquid crystal display panel tends to be enlarged. However, if a defective product is generated at the time of initial bonding, the optical film is removed from the liquid crystal cell, and the liquid crystal cell is washed and reused, if a conventional adhesive having a high adhesive force is used. Not only is it difficult to remove the optical film due to its strong adhesive force during the re-peeling of the optical film, but also the possibility of destroying expensive liquid crystal cells is high, resulting in a significant increase in production costs. It is supposed to end.

  Therefore, as LCDs become larger, attempts to develop highly functional pressure-sensitive adhesives that achieve various adhesive properties such as adhesiveness and reworkability are continuing. For example, Japanese Patent No. 3022993 (Patent Document 1) proposes an acrylic pressure-sensitive adhesive composition containing epoxysilane for the purpose of providing a polarizing plate having excellent durability in a high-temperature and high-humidity environment. .

  In addition, in Patent Nos. 3533446 (Patent Document 2) and 5262672 (Patent Document 3), not only can the polarizing plate be adhered to the substrate surface with good adhesive strength, but also if necessary, the substrate can be attached to the substrate. In order to peel the polarizing plate from the surface of the substrate without damaging or leaving the adhesive, it contains an acrylic polymer and a compound having a β-ketoester group and a hydrolyzed silyl group or a hydrolyzed condensate thereof. An adhesive composition has been proposed.

  Japanese Patent No. 4771102 (Patent Document 4), Japanese Patent No. 5365609 (Patent Document 5), Japanese Patent No. 5365610 (Patent Document 6), and Japanese Translation of PCT International Publication No. 2008-506028 (Patent Document 7) include: In addition to being able to bond the polarizing plate with good adhesive strength, if necessary, in order to peel off the polarizing plate from the surface of the substrate without damaging the substrate or leaving the adhesive, An adhesive composition containing a compound having a heterocyclic structure group, a urethane or urea linking group and a hydrolyzed silyl group has been proposed.

  In addition, Japanese Patent Application Laid-Open No. 2011-219765 (Patent Document 8), Japanese Patent No. 4840888 (Patent Document 9), and International Publication No. 2010/26995 (Patent Document 10) have low initial adhesive force and are reworkable. An acrylic adhesive containing an organosilicon compound with an alkoxysilyl group at the end of the polyether has been proposed as an adhesive that has excellent adhesive strength under high temperature and humidity after pasting and has excellent durability over the long term. Yes.

  By including such a silane compound, the substrate and the polarizing plate can maintain an appropriate adhesive strength to the extent required in the environment in which the substrate is actually used, and the adhesive strength is not excessively increased by heating or the like. The polarizing plate can be easily peeled off without damaging the liquid crystal element.

  However, the performance required of pressure-sensitive adhesives to support the large-size trend of LCDs is that the initial adhesive force when attached to glass is low and not only has excellent reworkability, but also needs to exhibit high adhesiveness under high temperature and high humidity. If this is not the case, bubbles and peeling may occur and durability may be weakened.

  JP-A-8-199144 (Patent Document 11) discloses a silane-based compound in order to provide a pressure-sensitive adhesive composition having little change over time in cohesive force and adhesive force even under high temperature and high humidity, and having excellent curved surface adhesive force. There has been proposed a technique of blending a curing agent with an acrylic resin obtained by polymerizing an acrylic monomer in the presence of.

  By compounding this silane compound, the substrate and the polarizing plate can maintain an appropriate adhesive strength to the extent required in the environment where they are actually used, and the adhesive strength is not excessively increased by heating, It is described that the polarizing plate can be easily peeled without damaging the liquid crystal element.

  However, it can be said that it is preferable that the adhesive force is high, there is no bubble or peeling phenomenon, and the durability is excellent, rather than the small change with time of the cohesive force and adhesive force under high temperature and high humidity. That is, it shows an appropriate initial adhesive strength that can be re-peeled at the initial stage when it is pasted on glass, but it does not need to be peeled off as time passes, so it maintains a strengthened and stabilized adhesive strength. Can be said to be necessary.

  From this point of view, it cannot be said that the reworkability that can be improved by the adhesive modifier composed of the organosilicon compound described in Patent Documents 2 to 10, the moisture resistance after bonding, the adhesive strength, etc. are sufficient. There is room for improvement.

  From the above, there has been a demand for the development of a well-balanced pressure-sensitive adhesive that retains initial reworkability and high adhesive strength under high temperature and high humidity.

Japanese Patent No. 3022993 Japanese Patent No. 3533446 Japanese Patent No. 5262672 Japanese Patent No. 4771102 Japanese Patent No. 5365609 Japanese Patent No. 5365610 Special table 2008-506028 gazette JP 2011-219765 A Japanese Patent No. 4840888 International Publication No. 2010/26995 JP-A-8-199144

  The present invention has been made in view of the above circumstances, and when pasted on an adherend such as glass, the initial adhesive force is low and excellent in reworkability, and after pasting, under high temperature or high temperature and high humidity conditions. Adhesive composition capable of forming a pressure-sensitive adhesive layer excellent in long-term durability with increased adhesion to an adherend such as glass, a pressure-sensitive adhesive polarizing plate having a pressure-sensitive adhesive layer formed from this pressure-sensitive adhesive composition, and It aims at providing the liquid crystal display device which has this adhesion polarizing plate.

  As a result of intensive studies to achieve the above object, the present inventor uses, as an adhesion modifier, a silane coupling agent containing a structure in which a connecting chain of an epoxy group and a hydrolyzable silyl group has a specific chain length. As a result, the proportion of the organic portion increases compared to the silane coupling agent used in the existing technology, so the compatibility with the resin is improved and the bonding strength with the matrix resin having a hydroxyl group, mutual It has been found that a pressure-sensitive adhesive that is excellent in action and can simultaneously achieve both initial reworkability and high adhesive strength at high temperature or high temperature and high humidity because the hydrolyzability of the silyl group is low, and the present invention is made. It came.

（式中、Ｘは水素原子又は炭素数１〜４のアルキル基であり、Ｒは炭素数１〜６の一価炭化水素基であり、Ａは炭素数６〜１０の二価炭化水素基であり、Ｙはエポキシ構造基であり、ｎは１〜３の整数である。）
で表されるエポキシ基含有有機ケイ素化合物及び／又はその部分加水分解物もしくは部分加水分解縮合物からなる接着性改質剤と
を含有し、（Ａ）成分１００質量部に対して、（Ｂ）成分が０．００１〜１０質量部の割合であることを特徴とする粘着剤組成物。
〔２〕
上記式（１）におけるＹのエポキシ構造基が、グリシジルオキシ基又はシクロヘキセンオキシド構造基であることを特徴とする〔１〕記載の粘着剤組成物。
〔３〕
（Ｂ）成分のエポキシ基含有有機ケイ素化合物が、下記一般式（２）

（式中、Ｘ、Ｒ、ｎは〔１〕の定義の通りである。）
で表されるものであることを特徴とする〔１〕又は〔２〕記載の粘着剤組成物。
〔４〕
（Ａ）（ａ）炭素数１〜１２のアルキル基を有する（メタ）アクリル酸エステルモノマー９０〜９９．９質量部と、（ｂ）架橋可能な官能基を含むビニル系モノマー及び／又は（メタ）アクリル系モノマー０．１〜１０質量部とを共重合して得られるアクリル系ポリマー：１００質量部、
（Ｂ）〔１〕〜〔３〕のいずれかに記載の接着性改質剤：０．００１〜１０質量部、
（Ｃ）多官能性架橋剤：０．０１〜１０質量部
を含むことを特徴とする〔１〕〜〔３〕のいずれかに記載の粘着剤組成物。
〔５〕
上記（ｂ）成分の架橋可能な官能基を含むビニル系モノマー又は（メタ）アクリル系モノマーが、２−ヒドロキシエチル（メタ）アクリレート、３−ヒドロキシプロピル（メタ）アクリレート、４−ヒドロキシブチル（メタ）アクリレート、ジエチレングリコールモノ（メタ）アクリレート、ジプロピレングリコールモノ（メタ）アクリレート、（メタ）アクリロキシプロピルトリメトキシシラン、（メタ）アクリロキシプロピルトリエトキシシラン、（メタ）アクリロキシプロピルメチルジメトキシシラン、（メタ）アクリロキシプロピルメチルジエトキシシラン、（メタ）アクリロキシメチルトリメトキシシラン、（メタ）アクリロキシメチルトリエトキシシラン、（メタ）アクリロキシメチルメチルジメトキシシラン、（メタ）アクリロキシメチルメチルジエトキシシラン、（メタ）アクリル酸、（メタ）アクリル酸二量体、イタコン酸、マレイン酸及びマレイン酸無水物からなる群より選ばれる１種以上のモノマーである〔４〕記載の粘着剤組成物。
〔６〕
（Ｃ）成分の多官能性架橋剤が、イソシアネート系化合物、エポキシ系化合物、アジリジン系化合物及び金属キレート系化合物からなる群より選ばれる１種以上の架橋剤である〔４〕又は〔５〕記載の粘着剤組成物。
〔７〕
偏光フィルムと、この偏光フィルムの片面又は両面に〔１〕〜〔６〕のいずれかに記載の粘着剤組成物から形成される粘着剤層とを有することを特徴とする粘着偏光板。
〔８〕
更に、保護層、反射層、位相差板、光視野角補償フィルム及び輝度向上フィルムからなる群より選択される１種以上の層を有する〔７〕記載の粘着偏光板。
〔９〕
一対のガラス基板間に液晶が封入された液晶セルと、この液晶セルの片面又は両面に貼着された〔７〕又は〔８〕記載の粘着偏光板とを有する液晶パネルを含むことを特徴とする液晶表示装置。 Therefore, this invention provides the following adhesive composition, an adhesive polarizing plate, and a liquid crystal display device.
[1]
(A) an acrylic polymer;
(B) The following general formula (1)

(In the formula, X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and A is a divalent hydrocarbon group having 6 to 10 carbon atoms. Y is an epoxy structural group, and n is an integer of 1 to 3.)
An epoxy group-containing organosilicon compound and / or an adhesive modifier composed of a partially hydrolyzed product or a partially hydrolyzed condensate thereof, and (A) 100 parts by mass of component (B) A pressure-sensitive adhesive composition, wherein the component is a proportion of 0.001 to 10 parts by mass.
[2]
The pressure-sensitive adhesive composition according to [1], wherein the epoxy structural group of Y in the formula (1) is a glycidyloxy group or a cyclohexene oxide structural group.
[3]
The (B) component epoxy group-containing organosilicon compound has the following general formula (2):

(In the formula, X, R, and n are as defined in [1].)
The pressure-sensitive adhesive composition according to [1] or [2], which is represented by:
[4]
(A) (a) 90 to 99.9 parts by mass of a (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms, and (b) a vinyl monomer and / or (meta ) Acrylic polymer obtained by copolymerizing 0.1 to 10 parts by mass of acrylic monomer: 100 parts by mass,
(B) Adhesive modifier according to any one of [1] to [3]: 0.001 to 10 parts by mass,
(C) Polyfunctional crosslinking agent: The pressure-sensitive adhesive composition according to any one of [1] to [3], comprising 0.01 to 10 parts by mass.
[5]
The vinyl monomer or (meth) acrylic monomer containing the crosslinkable functional group of the component (b) is 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) Acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltriethoxysilane, (meth) acryloxypropylmethyldimethoxysilane, (meth ) Acryloxypropylmethyldiethoxysilane, (meth) acryloxymethyltrimethoxysilane, (meth) acryloxymethyltriethoxysilane, (meth) acryloxymethylmethyldimethoxysilane, (meth) acrylic [4] The monomer according to [4], which is one or more monomers selected from the group consisting of xylmethylmethyldiethoxysilane, (meth) acrylic acid, (meth) acrylic acid dimer, itaconic acid, maleic acid and maleic anhydride. Adhesive composition.
[6]
[4] or [5], wherein the polyfunctional crosslinking agent as component (C) is one or more crosslinking agents selected from the group consisting of isocyanate compounds, epoxy compounds, aziridine compounds and metal chelate compounds. Adhesive composition.
[7]
An adhesive polarizing plate comprising a polarizing film and an adhesive layer formed from the adhesive composition according to any one of [1] to [6] on one or both surfaces of the polarizing film.
[8]
The adhesive polarizing plate according to [7], further comprising one or more layers selected from the group consisting of a protective layer, a reflective layer, a retardation plate, a light viewing angle compensation film, and a brightness enhancement film.
[9]
It includes a liquid crystal panel having a liquid crystal cell in which liquid crystal is sealed between a pair of glass substrates, and an adhesive polarizing plate according to [7] or [8] attached to one or both surfaces of the liquid crystal cell, Liquid crystal display device.

  The pressure-sensitive adhesive composition of the present invention is obtained by blending a silane coupling agent containing a structure in which a connecting chain of an epoxy group and a hydrolyzable silyl group has a specific chain length as an essential component of an adhesive modifier, thereby performing initial reworking. And high adhesive strength under high temperature or high humidity.

  Hereinafter, the present invention will be specifically described. In the present invention, the “silane coupling agent” is included in the “organosilicon compound”.

The pressure-sensitive adhesive composition according to the present invention contains (A) an acrylic polymer and (B) an adhesion modifier.
Hereinafter, the acrylic polymer as the component (A) and the adhesion modifier as the component (B) will be described in detail.

(A) Acrylic polymer (A) As an acrylic polymer of a component, (a) (meth) acrylic acid ester monomer 90-19.9 mass part which has a C1-C12 alkyl group; (b) Crosslinkable A (meth) acrylic copolymer obtained by copolymerizing 0.1 to 10 parts by mass of a vinyl monomer and / or a (meth) acrylic monomer containing a functional group is preferably used.

  Here, the (a) (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms used in the composition of the present invention is 90 to 99.9 mass out of 100 mass parts of the monomer to be copolymerized. Part, particularly 91 to 99 parts by weight, and if the content is less than 90 parts by weight, the initial adhesive force may be reduced, and if it exceeds 99.9 parts by weight, the cohesive force is reduced and the durability is decreased. May cause problems.

  The (a) component (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms is other than the (b) component (meth) acrylic monomer containing a crosslinkable functional group. An alkyl ester having 1 to 12 carbon atoms of (meth) acrylic acid can be used, and an alkyl ester having 2 to 8 carbon atoms is more preferable. That is, in the alkyl (meth) acrylate, the cohesive strength of the pressure-sensitive adhesive may be reduced if the alkyl group is in a long chain form. Therefore, the carbon number of the alkyl group is 1 in order to maintain the cohesive strength at high temperatures. The range of -12 is preferable, More preferably, it is the range of 2-8.

  Such (meth) acrylic acid ester monomers include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) ) Acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, and the like. You may mix and use the above.

  (B) The vinyl monomer and (meth) acrylic monomer containing the crosslinkable functional group of the component react with the crosslinking agent so that the cohesive force of the adhesive is not broken under high temperature or high temperature and high humidity conditions. Provides cohesive strength or adhesive strength due to chemical bonding. Component (b) is used in an amount of 0.1 to 10 parts by weight, particularly 1 to 9 parts by weight, based on 100 parts by weight of the monomer to be copolymerized, and less than 0.1 parts by weight. In some cases, cohesive failure tends to occur under high temperature and high humidity. When the amount exceeds 10 parts by mass, the compatibility is remarkably reduced, surface migration occurs, and the fluidity decreases while the cohesive force increases and stress increases. Mitigation ability may decrease.

  Examples of the vinyl monomer or (meth) acrylic monomer having a crosslinkable functional group as the component (b) include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl ( Monomers containing hydroxyl groups such as (meth) acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, (meth) acrylic acid, (meth) acrylic acid dimer, itaconic acid, maleic acid and maleic anhydride Monomers containing a carboxyl group such as (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltriethoxysilane, (meth) acryloxypropylmethyldimethoxysilane, (meth) acryloxypropylmethyldiethoxysilane, (Me ) Monomers containing hydrolyzable silyl groups such as acryloxymethyltrimethoxysilane, (meth) acryloxymethyltriethoxysilane, (meth) acryloxymethylmethyldimethoxysilane, (meth) acryloxymethylmethyldiethoxysilane, etc. Although it is mentioned, it is not restricted to these. The said monomer can be used individually by 1 type or in mixture of 2 or more types.

  In the present invention, when the acrylic copolymer is produced, other copolymerizable monomers are further used in order to adjust the glass transition temperature of the pressure-sensitive adhesive composition and to impart other functionality. Can do. Specifically, copolymerizable monomers such as acrylonitrile, styrene, glycidyl (meth) acrylate and vinyl acetate can be used. The blending ratio of these copolymerizable monomers is preferably 0.1 to 9.9 parts by mass, more preferably 0.5 to 8 parts by mass, out of 100 parts by mass of the monomer to be copolymerized.

  The viscoelastic properties of the pressure-sensitive adhesive composition are mainly based on the molecular weight, molecular weight distribution, or molecular structure abundance of the polymer chain, and are particularly determined by the molecular weight. Therefore, the (meth) acrylic copolymer used in the present invention is used. The molecular weight (weight average molecular weight: Mw) of the polymer is preferably 800,000 to 2,000,000, more preferably 900,000 to 1.9 million. The weight average molecular weight is a standard polystyrene equivalent value measured by gel permeation chromatography (GPC). If the molecular weight is too small, the desired viscoelastic properties may not be obtained. If the molecular weight is too large, the viscosity of the polymer becomes very high and handling becomes difficult, which may reduce productivity.

  Such a copolymer can be produced through a normal radical copolymerization process. In the present invention, the polymerization method of the polymer is not particularly limited, and the polymer can be produced by a general method such as a solution polymerization method, a photopolymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. Among these, the solution polymerization method is preferable from the viewpoint of productivity. In this case, the polymerization temperature is preferably 50 to 140 ° C. and the reaction time is preferably 1 to 24 hours. It is preferable to add the initiator in a state where the monomers are uniformly mixed.

（式中、Ｘは水素原子又は炭素数１〜４のアルキル基であり、Ｒは炭素数１〜６の一価炭化水素基であり、Ａは炭素数６〜１０の二価炭化水素基であり、Ｙはエポキシ構造基であり、ｎは１〜３の整数である。） (B) Adhesive modifier [organosilicon compound (silane coupling agent)]
The adhesive modifier which is a basic component of the present invention is an epoxy group-containing organosilicon compound represented by the following general formula (1) and / or a partial hydrolyzate or partial hydrolyzate condensate thereof.

(In the formula, X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and A is a divalent hydrocarbon group having 6 to 10 carbon atoms. Y is an epoxy structural group, and n is an integer of 1 to 3.)

  In addition to the above organosilicon compound alone, the adhesive modification component includes the structure in which the hydrolyzable silyl group part is partially hydrolyzed, and the partial hydrolyzed condensate that is further oligomerized by intermolecular condensation. Is included in the adhesive modification component.

  Specific examples of the alkyl group having 1 to 4 carbon atoms in X include a methyl group, an ethyl group, a propyl group, and a butyl group, and these may be linear or branched. A methyl group and an ethyl group are preferable from the viewpoint of easy availability of raw materials and productivity.

  Specific examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms in R include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group as the alkyl group. These may be linear, branched or cyclic. Moreover, a phenyl group is mentioned as an aryl group. A methyl group is preferable from the viewpoint of easy availability of raw materials and productivity.

  Specific examples of the divalent hydrocarbon group having 6 to 10 carbon atoms in A include alkylene groups such as a hexylene group, a heptylene group, an octylene group, a nonalene group, and a decylene group. These may be linear or branched. Preferably, it is a linear octylene group from the viewpoint of easy availability of raw materials. The structural part is the main structure of the present invention, and the existing technology is generally a propylene group, and it is an essential factor that the chain length is longer than that.

  Specific examples of the epoxy structural group in Y are a glycidyloxy group or a cyclohexene oxide structural group, and more preferably a glycidyloxy group from the viewpoint of availability of raw materials.

（式中、Ｘ、Ｒ、ｎは上記と同義である。）
で示される。
更に好ましくは、原料の入手の容易性、生産性の観点からＸがメチル基、ｎ＝３であるものである。 From these points, as a more preferable structure of the epoxy group-containing organosilicon compound, the following general formula (2)

(In the formula, X, R, and n are as defined above.)
Indicated by
More preferably, X is a methyl group and n = 3 from the viewpoint of easy availability of raw materials and productivity.

  In the pressure-sensitive adhesive composition of the present invention, 0.001 to 10 parts by mass of the (B) adhesion modifying component is blended with 100 parts by mass of the (A) acrylic polymer. If it is less than the lower limit, the desired adhesive modification effect does not appear, and if it exceeds the upper limit, the effect is saturated, the cost effectiveness is reduced, and the original silane coupling agent is This is not preferable because the effect of improving the adhesion is increased, and the initial adhesion may be excessive.

[Adhesive composition]
The pressure-sensitive adhesive composition of the present invention comprises the above components (A) and (B) as essential components, but preferably further contains (C) a polyfunctional crosslinking agent, and more specifically,
(A) Acrylic polymer: 100 parts by mass,
(B) Adhesive modifier: 0.001 to 10 parts by mass,
(C) Polyfunctional crosslinking agent: It is preferable to contain 0.01-10 mass parts.

  Here, in the pressure-sensitive adhesive composition of the present invention, the polyfunctional crosslinking agent as the component (C) plays a role of increasing the cohesive force of the pressure-sensitive adhesive by reacting with a carboxyl group, a hydroxyl group or the like. The content of the crosslinking agent is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the copolymer (A). If the amount is too large, aggregation may be severe, and it may be difficult to form an adhesive sheet or the like. If the amount is too small, the desired effect of improving the cohesive force may not be obtained.

  As the polyfunctional crosslinking agent, an isocyanate-based, epoxy-based, aziridine-based, metal chelate-based crosslinking agent or the like can be used, and among them, the isocyanate-based crosslinking agent is easy to use. Examples of the isocyanate crosslinking agent include tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoform diisocyanate, tetramethylxylene diisocyanate, naphthalene diisocyanate, and a reaction product of these with a polyol such as trimethylol propane (trimethylol propane tri Range isocyanate adducts, etc.).

  Epoxy crosslinking agents include ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N, N ′, N′-tetraglycidylethylenediamine, glycerin diglycidyl ether, glycerin triglycidyl ether, polyglycerin polyglycidyl luter. And sorbitol-based polyglycidyl ether.

  Examples of the aziridine-based crosslinking agent include N, N′-toluene-2,4-bis (1-aziridinecarboxide), N, N′-diphenylmethane-4,4′-bis (1-aziridinecarboxide), and triethylene. Examples include melamine, bisisoprotaloyl-1- (2-methylaziridine), and tri-1-aziridinylphosphine oxide.

  Examples of the metal chelate-based crosslinking agent include compounds in which a polyvalent metal such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and vanadium is coordinated to acetylacetone or ethyl acetoacetate.

  Moreover, in order to adjust adhesive performance, the tackifier resin can further be added to the adhesive composition of this invention. The content can be used in the range of 1 to 100 parts by mass, particularly 5 to 90 parts by mass with respect to 100 parts by mass of the (A) (meth) acrylic copolymer. At this time, if the amount is less than 1 part by mass, the effect of adjustment may be insufficient. If the amount exceeds 100 parts by mass, the regularity or cohesion of the pressure-sensitive adhesive may be reduced.

  Examples of tackifying resins include (hydrogenated) hydrocarbon resins, (hydrogenated) rosin resins, (hydrogenated) rosin ester resins, (hydrogenated) terpene resins, (hydrogenated) terpene phenol resins, polymerized rosins. Resins, polymerized rosin ester resins, and the like can be used, and these can be used alone or in admixture of two or more.

  In addition to the above components, a low molecular weight material such as a plasticizer and a leveling agent, an epoxy resin, a curing agent, and the like can be mixed and used as an additional component as necessary, as long as the object of the present invention is not impaired. Agents, antioxidants, decolorizers, reinforcing agents, fillers, antifoaming agents, surfactants, and the like can be appropriately added and used according to general purposes.

  The manufacturing method of the adhesive composition of this invention is not specifically limited, It can obtain by mixing above described component (A)-(C) and another arbitrary component by a normal method. The mixing condition is preferably 10 minutes to 10 hours at 10 to 150 ° C. In this case, the polyfunctional epoxy group-containing organosilicon compound can be added and used in the blending step after the polymerization of the (meth) acrylic copolymer, and the (meth) acrylic copolymer production step Even when added in, the same effect is exhibited. In addition, the polyfunctional cross-linking agent can be uniformly coated when the functional group cross-linking reaction of the cross-linking agent hardly occurs in the blending process for forming the pressure-sensitive adhesive layer obtained by curing the pressure-sensitive adhesive composition. It becomes. After the coating, when a drying and aging process is performed, a crosslinked structure is formed, and an adhesive layer having elasticity and strong cohesion is obtained.

  The pressure-sensitive adhesive composition of the present invention thus obtained is applied to an adherend such as a glass plate, a plastic film, paper and the like, and is 25 to 150 ° C., 20 to 90% RH, 5 minutes to 5 hours, particularly The pressure-sensitive adhesive layer can be formed by curing at 40 to 80 ° C. and 25 to 60% RH for 10 minutes to 3 hours.

  The pressure-sensitive adhesive composition of the present invention is desirably used after sufficiently removing components that induce bubbles such as volatile components and reaction residues. When the crosslinking density and molecular weight are excessively low and the elastic modulus of the pressure-sensitive adhesive layer is excessively low, small bubbles existing between the adherend and the pressure-sensitive adhesive layer such as a glass plate in a high temperature state become large, A scatterer is formed inside the pressure-sensitive adhesive layer. Further, when an adhesive layer having an excessively large elastic modulus is used for a long period of time, a peeling phenomenon occurs at an end portion of the adhesive layer (sheet) due to an excessive crosslinking reaction.

  In consideration of the optimum physical balance, the crosslink density of the pressure-sensitive adhesive layer is suitably 5 to 95% by mass, particularly 7 to 93% by mass. The cross-linking density refers to a value obtained by mass% of the amount of a portion where a cross-linked structure that is not dissolved in a solvent is formed by a generally known method for measuring the gel content of an adhesive. At this time, when the cross-linking density of the pressure-sensitive adhesive layer is less than 5% by mass, the cohesive force of the pressure-sensitive adhesive layer is lowered, and there is a possibility that problems of adhesion durability such as bubbles or peeling may occur. When it exceeds, it may not be attached tightly and durability may be weakened.

[Adhesive polarizing plate]
Next, a pressure-sensitive adhesive polarizing plate including a pressure-sensitive adhesive layer obtained by applying and curing the pressure-sensitive adhesive composition on one side or both sides of a polarizing film or the like will be described.
The pressure-sensitive adhesive polarizing plate of the present invention has a polarizing film or polarizing element, and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on one or both sides of the polarizing film or polarizing element. It does not specifically limit about the polarizing film or polarizing element which comprises a polarizing plate. Examples of the polarizing film include a film obtained by stretching a film made of a polyvinyl alcohol resin containing a polarizing component such as iodine or a heterochromatic dye, and the thickness of these polarizing films is not limited. , Can be molded to a normal thickness.

  Examples of the polyvinyl alcohol resin include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, and a saponified product of an ethylene / vinyl acetate copolymer.

  In the present invention, the method for forming the pressure-sensitive adhesive layer on the polarizing film is not particularly limited, and the pressure-sensitive adhesive composition is directly applied to the surface of the polarizing film using a bar coater and dried. A method of applying the composition to the surface of the peelable substrate and drying it, and then transferring the pressure-sensitive adhesive layer formed on the surface of the peelable substrate to the surface of the polarizing film and then aging can be employed. . In this case, drying is preferably 25 to 150 ° C. and 20 to 90% RH for 5 minutes to 5 hours, and aging is preferably 25 to 150 ° C. and 20 to 90% RH for 5 minutes to 5 hours.

  The thickness of the pressure-sensitive adhesive layer is not particularly limited, but is usually preferably 0.01 to 100 μm, more preferably 0.1 to 50 μm. When the thickness of the pressure-sensitive adhesive layer is smaller than the above range, the effect as the pressure-sensitive adhesive layer may be insufficient, and when the thickness is larger than the above range, the effect of the pressure-sensitive adhesive layer may be saturated and the cost may be increased.

  The polarizing film (adhesive polarizing plate) having the pressure-sensitive adhesive layer of the present invention thus obtained has additional functions such as a protective layer, a reflective layer, a phase difference plate, a light viewing angle compensation film, and a brightness enhancement film. One or more layers providing the above can be laminated.

  In particular, on both surfaces of a polarizing film having a pressure-sensitive adhesive layer, a cellulose film such as triacetyl cellulose, a polycarbonate film, a polyester film such as a polyethylene terephthalate film, a polyethersulfone film, polyethylene, polypropylene, and a copolymer thereof. A multilayer film or the like on which a protective film such as a polyolefin-based film is laminated can be formed. At this time, the thickness of these protective films is not particularly limited, and can be formed to a normal thickness.

[Liquid Crystal Display]
The adhesive polarizing plate of the present invention can be applied to general liquid crystal display devices in general, and the type of the liquid crystal panel is not particularly limited. In particular, it is preferable to configure a liquid crystal display device including a liquid crystal panel in which the adhesive polarizing plate of the present invention is bonded to one or both sides of a liquid crystal cell in which liquid crystal is sealed between a pair of glass substrates.

  In addition to the polarizing film described above, the pressure-sensitive adhesive composition of the present invention is an industrial sheet, particularly a reflective sheet, a structural pressure-sensitive adhesive sheet, a photographic pressure-sensitive adhesive sheet, a lane display pressure-sensitive adhesive sheet, an optical pressure-sensitive adhesive product, and an electronic component. Can be used for any purpose. Further, the present invention can also be applied to application fields having the same concept of action, such as laminate products having a multi-layer structure, that is, general commercial adhesive sheet products, medical patches, and heating activations.

  The pressure-sensitive adhesive composition of the present invention is a (meth) acrylic pressure-sensitive adhesive containing a silane coupling agent having a coordinating functional group, and has a low initial adhesive force when attached to glass or the like. Excellent, adhesive strength after wet heat treatment after pasting is sufficiently high, and excellent long-term durability.

  EXAMPLES Hereinafter, although a synthesis example, an Example, and a comparative example are shown and this invention is demonstrated in more detail, this invention is not limited to these Examples.

[(A) Acrylic polymer synthesis example]
In a 1 L separable flask equipped with a stirrer, reflux condenser, dropping funnel and thermometer, 98.1 g of n-butyl acrylate (BA), 0.6 g of acrylic acid (AA), 2-hydroxyethyl methacrylate (2-HEMA) ) 1.3 g was charged, and 100 g of ethyl acetate was charged as a solvent and dissolved. Thereafter, nitrogen gas bubbling was performed for 1 hour to remove oxygen, and the reaction system was purged with nitrogen and maintained at 62 ° C. Into this, 0.03 g of azobisisobutyronitrile as a polymerization initiator was added while stirring and reacted at 62 ° C. for 8 hours to obtain a (meth) acrylic copolymer as a base polymer.

[Examples and Comparative Examples]
With respect to 100 parts by mass of (A) acrylic polymer: (meth) acrylic copolymer obtained in Synthesis Example, (B) Adhesive modifier: A-1 to 4 and B-1 to 3 below Trimethylolpropane tolylene diisocyanate adduct (TDI) as a silane coupling agent and (C) polyfunctional crosslinking agent were mixed in the blending composition shown in Table 1 to obtain an adhesive composition.
After the obtained pressure-sensitive adhesive composition was coated on a release paper and dried, a uniform pressure-sensitive adhesive layer of 25 μm was obtained. The pressure-sensitive adhesive layer produced in this way was subjected to pressure-sensitive adhesive processing on an iodine-type polarizing plate having a thickness of 185 μm, and then the obtained polarizing plate was cut into an appropriate size and used for each evaluation.

  About the test piece of the manufactured polarizing plate, it evaluated about the change of adhesive force on durability, glass adhesiveness, rework property, heat resistance, or heat-and-moisture resistance conditions through the evaluation test method shown below, and the result is shown in Tables 2-4. Indicated.

シランＢ−３：両末端アルコキシシリル変性ＰＯ型ポリエーテル化合物
（カネカ（株）製サイリルＳＡＴ１０） In Table 1, abbreviations are as follows.
TDI: cross-linking agent, tolylene diisocyanate adduct of trimethylolpropane silane A-1: glycidoxyoctyltrimethoxysilane silane A-2: glycidoxyoctylmethyldimethoxysilane silane A-3: glycidoxyoctyltriethoxysilane Silane A-4: Glycidoxyhexyltrimethoxysilane silane B-1: Glycidoxypropyltrimethoxysilane
(KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.)
Silane B-2:

Silane B-3: Both end alkoxysilyl-modified PO type polyether compound
(Sailyl SAT10 manufactured by Kaneka Corporation)

Evaluation test <durability>
A polarizing plate (90 mm × 170 mm) coated with an adhesive was attached to a glass substrate (110 mm × 190 mm × 0.7 mm) with the optical absorption axes crossed on both sides to obtain a test piece. At this time, the applied pressure was about 5 kgf / cm ³ , and the work was performed in a clean room so that bubbles and foreign matters were not generated.
In order to evaluate the moisture resistance and heat resistance characteristics of this test piece, after leaving it for 1,000 hours under the condition of 60 ° C./90% relative humidity, the presence or absence of generation of bubbles or peeling was confirmed. Regarding heat resistance, after standing at 80 ° C./30% relative humidity for 1,000 hours, bubbles and peeling were observed. In addition, before evaluating the state of a test piece, it left still at room temperature (25 degreeC) for 24 hours. The results are shown in Table 2.
Evaluation criteria for durability evaluation are as follows.
○: No bubbles or exfoliation phenomenon △: Air bubbles or exfoliation phenomenon slightly present ×: Many bubbles or exfoliation phenomena exist

<Glass adhesive strength, adhesive strength change under high temperature and high temperature and humidity conditions>
After the polarizing plate coated with the adhesive was aged for 7 days at room temperature (23 ° C./60% RH), the polarizing plate was cut into 1 inch × 6 inch size, and a 2 kg rubber roller was used. Affixed to a non-alkali glass having a thickness of 0.7 mm. After storing at room temperature, the initial adhesive force was measured after 1 hour, then aged at 50 ° C. for 4 hours, and then stored at room temperature for 1 hour, and then the adhesive force was measured. The results are shown in Table 2.

In order to see the degree of increase in adhesive strength under high temperature and high temperature and high humidity conditions, after aging according to time under the conditions of 60 ° C./30% RH and 60 ° C./90% RH, respectively, it is allowed to cool at room temperature for 1 hour. The adhesive strength was measured. The results are shown in Tables 3 and 4.
At this time, a tensile tester was used to measure the adhesive strength, and the peel strength was measured at a speed of 300 mm / min and an angle of 180 °.

<Reworkability>
After a polarizing plate (90 mm × 170 mm) coated with a pressure-sensitive adhesive was attached to a glass substrate (110 mm × 190 mm × 0.7 mm), it was aged at room temperature for 1 hour (initial adhesive force) and 50 ° C. × 4 hours, After allowing to cool at room temperature for 1 hour, the polarizing plate was peeled off from the glass. The results are shown in Table 2.
Evaluation criteria for reworkability are as follows.
○: Removable easily △: Removable slightly difficult ×: Unpeelable, glass breakage

  Regarding polarizing plates to which the adhesives of Examples and Comparative Examples were applied, evaluation results on durability, glass adhesion, reworkability, changes in adhesive strength under high temperature and high temperature and humidity obtained through the above evaluation methods Are shown in Tables 2 to 4 below.

Comparative Example 1 does not contain an adhesion modifier and does not exhibit sufficient adhesion after heat curing. Comparative Example 2 is a case where an epoxy silane coupling agent, which is an existing technology, is used. Since the epoxy-silyl linking chain of the compound is propylene and the hydrophobic property of the whole molecule is low, the initial adhesive force is too high and rework is performed. Sex does not appear. Comparative Examples 3 and 4 are existing silane materials that contribute to reworkability and adhesion after curing, but the final adhesion strength after curing is insufficient and reliability is lacking. In Comparative Example 5, the effect is insufficient because there are too few adhesive modifier components used. On the other hand, in Comparative Example 6, since the amount used was too large, unnecessary adhesion was developed from the beginning, and the reworkability was insufficient.
From the above, it is proved that the composition of the present invention is a pressure-sensitive adhesive composition excellent in initial rework, exhibiting sufficient adhesion with glass by high temperature and high temperature and high humidity treatment, and excellent in long-term durability. To do.

Claims (9)

(A) an acrylic polymer;
(B) The following general formula (1)

(In the formula, X is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, R is a monovalent hydrocarbon group having 1 to 6 carbon atoms, and A is a divalent hydrocarbon group having 6 to 10 carbon atoms. Y is an epoxy structural group, and n is an integer of 1 to 3.)
An epoxy group-containing organosilicon compound and / or an adhesive modifier composed of a partially hydrolyzed product or a partially hydrolyzed condensate thereof, and (A) 100 parts by mass of component (B) A pressure-sensitive adhesive composition, wherein the component is a proportion of 0.001 to 10 parts by mass.   The pressure-sensitive adhesive composition according to claim 1, wherein the epoxy structural group of Y in the formula (1) is a glycidyloxy group or a cyclohexene oxide structural group. The (B) component epoxy group-containing organosilicon compound has the following general formula (2):

(Wherein X, R and n are as defined in claim 1).
It is represented by these, The adhesive composition of Claim 1 or 2 characterized by the above-mentioned. (A) (a) 90 to 99.9 parts by mass of a (meth) acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms, and (b) a vinyl monomer and / or (meta ) Acrylic polymer obtained by copolymerizing 0.1 to 10 parts by mass of acrylic monomer: 100 parts by mass,
(B) Adhesive modifier according to any one of claims 1 to 3: 0.001 to 10 parts by mass,
(C) Polyfunctional crosslinking agent: 0.01-10 mass parts is contained, The adhesive composition of any one of Claims 1-3 characterized by the above-mentioned.   The vinyl monomer or (meth) acrylic monomer containing the crosslinkable functional group of the component (b) is 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) Acrylate, diethylene glycol mono (meth) acrylate, dipropylene glycol mono (meth) acrylate, (meth) acryloxypropyltrimethoxysilane, (meth) acryloxypropyltriethoxysilane, (meth) acryloxypropylmethyldimethoxysilane, (meth ) Acryloxypropylmethyldiethoxysilane, (meth) acryloxymethyltrimethoxysilane, (meth) acryloxymethyltriethoxysilane, (meth) acryloxymethylmethyldimethoxysilane, (meth) acrylic 5. The monomer according to claim 4, which is at least one monomer selected from the group consisting of xylmethylmethyldiethoxysilane, (meth) acrylic acid, (meth) acrylic acid dimer, itaconic acid, maleic acid and maleic anhydride. Adhesive composition.   The pressure-sensitive adhesive according to claim 4 or 5, wherein the polyfunctional crosslinking agent of component (C) is one or more crosslinking agents selected from the group consisting of isocyanate compounds, epoxy compounds, aziridine compounds and metal chelate compounds. Agent composition.   A pressure-sensitive adhesive polarizing plate comprising a polarizing film and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to any one of claims 1 to 6 on one side or both sides of the polarizing film.   Furthermore, the adhesive polarizing plate of Claim 7 which has 1 or more types of layers selected from the group which consists of a protective layer, a reflection layer, a phase difference plate, a light viewing angle compensation film, and a brightness enhancement film.   9. A liquid crystal comprising a liquid crystal panel having a liquid crystal cell in which liquid crystal is sealed between a pair of glass substrates, and the adhesive polarizing plate according to claim 7 or 8 attached to one or both surfaces of the liquid crystal cell. Display device.