KR102207421B1 - Adhesive composition, adhesive polarizing plate and liquid crystal display device - Google Patents

Abstract

(X는 수소 원자 또는 탄소수 1 내지 4의 알킬기이고, R은 탄소수 1 내지 6의 1가 탄화수소기이고, A는 탄소수 6 내지 10의 2가 탄화수소기이고, Y는 에폭시 구조기이고, n은 1 내지 3의 정수임)
로 표시되는 에폭시기 함유 유기 규소 화합물 및/또는 그의 부분 가수분해물 또는 부분 가수분해 축합물을 포함하는 접착성 개질제
를 함유하고, (A) 성분 100질량부에 대하여, (B) 성분이 0.001 내지 10질량부의 비율인 점착제 조성물을 제공한다.
본 발명의 점착제 조성물은, 에폭시기와 가수분해성 실릴기의 연결쇄가 특정한 쇄 길이인 구조를 포함하는 실란 커플링제를 접착성 개질제 필수 성분으로서 배합함으로써, 초기 리워크성과, 고온 또는 고온 다습하에서의 고접착력을 양립할 수 있다. The present invention (A) an acrylic polymer,
(B) General formula (1)

(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, A is a divalent hydrocarbon group having 6 to 10 carbon atoms, Y is an epoxy structural group, and n is 1 Is an integer of 3)
An adhesion modifier comprising an epoxy group-containing organosilicon compound represented by and/or a partial hydrolyzate or partial hydrolyzed condensate thereof
It contains, with respect to 100 parts by mass of the component (A), to provide a pressure-sensitive adhesive composition in which the component (B) is 0.001 to 10 parts by mass.
The pressure-sensitive adhesive composition of the present invention contains a silane coupling agent having a structure in which the linking chain of the epoxy group and the hydrolyzable silyl group is a specific chain length, as an essential component of the adhesion modifier, so that initial rework property and high adhesion under high temperature or high temperature and humidity Are compatible.

Description

Adhesive composition, adhesive polarizing plate, and liquid crystal display device {ADHESIVE COMPOSITION, ADHESIVE POLARIZING PLATE AND LIQUID CRYSTAL DISPLAY DEVICE}

The present invention relates to a pressure-sensitive adhesive composition using a novel adhesive modifier, and more particularly, by using a silane coupling agent having a structure in which the linking chain of the epoxy group and the hydrolyzable silyl group is a specific chain length, Compared to the silane coupling agent, the organic portion occupies a larger proportion, and as a result, the compatibility with the resin is improved, and the bonding strength and interaction with the matrix resin having a hydroxyl group are excellent. Therefore, the adhesive and the substrate containing the matrix resin In addition to improving the adhesion of the silyl group, since the hydrolyzability of the silyl group is low, an adhesive composition capable of dramatically improving the initial rework property, an adhesive polarizing plate having an adhesive layer formed from the adhesive composition, and the adhesive polarizing plate. It relates to a liquid crystal display device.

The silane coupling agent has two or more different functional groups in the molecule, and functions as an intermediary for connecting an organic material and an inorganic material, which are usually difficult to couple. One of the functional groups is a hydrolyzable silyl group, and a silanol group is generated by the presence of water, and the 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. In addition, other functional groups are organic reactive groups such as vinyl, epoxy, amino, (meth)acrylic and mercapto groups that form chemical bonds with organic materials such as various synthetic resins. Using these properties, they are widely used as modifiers, adhesion aids, and various additives for organic and inorganic resins.

Among the uses of silane coupling agents, the use of pressure-sensitive adhesives as adhesive modifiers is one of the representative ones. For example, the pressure-sensitive adhesive for attaching a liquid crystal cell and an optical film is used to increase the size of a liquid crystal display (LCD) and widen it. Accordingly, the required adhesion performance is becoming highly advanced.

In the case of LCD, contrary to the initial expectation that it is difficult to increase the size of 20 inches or more, it is rapidly increasing in size. Major manufacturers have been focusing on the production of small panels of 20 inches or less so far, but in line with the recent trend, they are actively introducing the latest technologies and expanding their product range to large sizes of 20 inches or more.

As described above, in various optical films, the glass used in the manufacture of a liquid crystal display panel tends to increase in size. However, when a defective product occurs at the time of initial attachment, the optical film is removed from the liquid crystal cell, and the liquid crystal cell is washed and reused. If a conventional pressure-sensitive adhesive having high adhesive strength was used, the optical film was removed again. Not only is it difficult to remove the optical film due to its strong adhesion, but there is a high possibility of destroying an expensive liquid crystal cell, resulting in a significant increase in production cost.

Accordingly, with the increase in the size of LCDs, attempts to develop high-functional pressure-sensitive adhesives that are compatible with various adhesive performances such as adhesiveness and rework property have been continued. For example, Japanese Patent No. 3022993 (Patent Document 1) proposes an acrylic pressure-sensitive adhesive composition containing an epoxy silane for the purpose of providing a polarizing plate excellent in durability under a high temperature and high humidity environment.

In addition, Japanese Patent No. 3533446 (Patent Document 2) and Japanese Patent No. 55262672 (Patent Document 3) not only allow a polarizing plate to be adhered to the surface of the substrate with good adhesive strength, but also damage the substrate if necessary. Since the polarizing plate is peeled off the surface of the substrate without coating or leaving the pressure-sensitive adhesive, a pressure-sensitive adhesive composition comprising an acrylic polymer, a compound having a β-ketoester group and a hydrolyzed silyl group, or a hydrolyzed condensate thereof has been proposed.

Japanese Patent No. 4771102 (Patent Document 4), Japanese Patent No. 5365609 (Patent Document 5), Japanese Patent No. 5365610 (Patent Document 6), Japanese Patent Publication No. 2008-506028 (Patent Document 7) In addition, since the polarizing plate can be adhered to the surface of the substrate with good adhesive strength, and if necessary, the polarizing plate is peeled from the surface of the substrate without damaging the substrate or leaving an adhesive, so the acrylic polymer and the heterocyclic structure group , A pressure-sensitive adhesive composition comprising a compound having a urethane or urea linking group and a hydrolyzed silyl group is proposed.

In addition, in 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), the initial adhesive strength was low and reworked. An acrylic pressure-sensitive adhesive comprising an organosilicon compound having an alkoxysilyl group at the end of a polyether has been proposed as a pressure-sensitive adhesive having excellent properties and enhanced adhesive strength under high temperature and high humidity after attachment, and has excellent long-term durability.

By containing such a silane compound, the substrate and the polarizing plate can maintain an appropriate adhesive strength as required in an environment in which they are actually used, and the adhesive strength is not excessively increased by heating or the like, so that it does not damage the liquid crystal element and is easily It is believed that the polarizing plate can be peeled off.

However, in order to support the large tendency of LCD, the performance required for the pressure-sensitive adhesive is low in initial adhesion when adhering to glass, excellent reworkability, and high adhesion needs to be expressed under high temperature and high humidity. If not, there is a fear that air bubbles or peeling may occur, resulting in weak durability.

In Japanese Patent Laid-Open No. 8-199144 (Patent Document 11), an acrylic monomer in the presence of a silane-based compound in order to provide a pressure-sensitive adhesive composition having a small cohesive force and adhesive force with time change even under high temperature and high humidity, and excellent curved surface adhesion. A technique of blending a curing agent in an acrylic resin obtained by polymerization of

By blending this silane compound, the substrate and the polarizing plate can maintain an appropriate adhesive strength as required in an environment in which they are actually used, and the adhesive strength is not excessively increased by heating or the like, and the liquid crystal element is not damaged. It is described that it is possible to peel off the polarizing plate.

However, it can be said that it is preferable that the adhesive force is higher than that of the cohesive force and the adhesive force change over time under high temperature and high humidity, and there are no bubbles or peeling phenomenon, and that the durability is excellent. That is, the initial adhesion to the glass exhibits an adequate initial adhesive strength enough to be re-peelable, but as time passes, there is no need for peeling, so it can be said that it is necessary to maintain a strengthened and stabilized adhesive force.

From this point of view, the adhesion modifier containing the organosilicon compound described in Patent Documents 2 to 10 cannot be said to have sufficient rework properties that can be improved, moisture resistance after adhesion, adhesion, etc., and there is room for improvement. Remains.

From the above, development of a balanced pressure-sensitive adhesive that maintains initial rework properties and high adhesive strength under high temperature and high humidity has been desired.

Japanese Patent No. 3022993 Japanese Patent No. 3533446 Japanese Patent No. 5262672 Japanese Patent No. 4771102 Japanese Patent No. 5365609 Japanese Patent No. 5365610 Japanese Patent Publication No. 2008-506028 Japanese Patent Publication No. 2011-219765 Japanese Patent No. 4840888 International Publication No. 2010/26995 Japanese Patent Publication (Hei) 8-199144

The present invention has been made in view of the above circumstances, and when it is attached to an adherend such as glass, the initial adhesive strength is low, and the rework property is excellent, and after attaching, the adhesion to the adherend such as glass under the conditions of high temperature or high temperature and high humidity is improved. An object of the present invention is to provide a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer excellent in long-term durability, a pressure-sensitive adhesive polarizing plate having a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, and a liquid crystal display having the pressure-sensitive adhesive polarizing plate.

The inventors of the present invention repeated intensive studies to achieve the above object, and as a result of using a silane coupling agent having a structure in which the linking chain of the epoxy group and the hydrolyzable silyl group has a specific chain length, as an adhesion modifier, Compared to the silane coupling agent, the organic portion occupies a larger proportion, so the compatibility with the resin is improved, the bonding strength and interaction with the matrix resin having a hydroxyl group are excellent, and the hydrolysis of the silyl group is lowered. It was discovered that a pressure-sensitive adhesive capable of achieving both workability and high adhesion under high temperature or high temperature and high humidity was obtained, and the present invention was completed.

Accordingly, the present invention provides the following pressure-sensitive adhesive composition, an adhesive polarizing plate, and a liquid crystal display.

(1) (A) an acrylic polymer,

(B) the following general formula (1)

(Wherein, 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, A is a divalent hydrocarbon group having 6 to 10 carbon atoms, and Y is an epoxy structural group, n is an integer of 1 to 3)

Adhesion modifier comprising an organosilicon compound containing an epoxy group represented by and/or a partially hydrolyzed or partially hydrolyzed condensate thereof

A pressure-sensitive adhesive composition containing 0.001 to 10 parts by mass of the component (B) with respect to 100 parts by mass of the component (A).

[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] In the above [1] or [2], the epoxy group-containing organosilicon compound of the component (B) is represented by the following general formula (2)

(In the formula, X, R, and n are the same as the definition of [1])

Adhesive composition, characterized in that it is represented by.

[4] in any one of [1] to [3] above,

(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 including a crosslinkable functional group and/or 0.1 to 10 (meth)acrylic monomers Acrylic polymer obtained by copolymerizing parts by mass: 100 parts by mass,

(B) the adhesive modifier according to any one of the above [1] to [3]: 0.001 to 10 parts by mass,

(C) Multifunctional crosslinking agent: 0.01 to 10 parts by mass

Adhesive composition comprising a.

[5] In [4], the vinyl-based monomer or (meth)acrylic monomer containing a crosslinkable functional group of the component (b) is 2-hydroxyethyl (meth)acrylate or 3-hydroxypropyl (meth) )Acrylate, 4-hydroxybutyl(meth)acrylate, diethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, (meth)acryloxypropyltrimethoxysilane, (meth)acrylic Oxypropyltriethoxysilane, (meth)acryloxypropylmethyldimethoxysilane, (meth)acryloxypropylmethyldiethoxysilane, (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethyltriethoxysilane , (Meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, (meth)acrylic acid, (meth)acrylic acid dimer, itaconic acid, maleic acid and maleic anhydride selected from the group consisting of A pressure-sensitive adhesive composition of one or more monomers.

[6] In the above [4] or [5], the multifunctional crosslinking agent of the component (C) is at least one crosslinking agent selected from the group consisting of an isocyanate compound, an epoxy compound, an aziridine compound and a metal chelate compound. Phosphorus 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 at least one layer selected from the group consisting of a protective layer, a reflective layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film.

[9] A liquid crystal panel comprising a liquid crystal cell in which a liquid crystal is enclosed between a pair of glass substrates, and an adhesive polarizing plate according to the above [7] or [8] adhered to one or both sides of the liquid crystal cell. Liquid crystal display device.

The pressure-sensitive adhesive composition of the present invention contains a silane coupling agent having a structure having a specific chain length of the linking chain between the epoxy group and the hydrolyzable silyl group as an essential component of the adhesion modifier, so that the initial rework property and high adhesion under high temperature or high temperature and humidity are improved. Compatible.

Hereinafter, the present invention will be described in detail. In addition, in the present invention, the "silane coupling agent" is included in the "organic silicon compound".

The pressure-sensitive adhesive composition according to the present invention contains (A) an acrylic polymer and (B) an adhesive modifier.

Hereinafter, the acrylic polymer of the component (A) and the adhesive modifier of the component (B) will be described in detail.

(A) acrylic polymer

As the acrylic polymer of the component (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; (b) A (meth)acrylic copolymer obtained by copolymerizing 0.1 to 10 parts by mass of a vinyl-based monomer and/or a (meth)acrylic monomer containing a crosslinkable 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 preferably contained in an amount of 90 to 99.9 parts by mass, particularly 91 to 99 parts by mass, out of 100 parts by mass of the monomer to be copolymerized. If the content is less than 90 parts by mass, the initial adhesive strength may decrease, and if the content exceeds 99.9 parts by mass, a problem may occur in durability due to a decrease in cohesive strength.

In addition, the (meth)acrylic acid ester monomer having an alkyl group having 1 to 12 carbon atoms of the component (a) is other than the (meth)acrylic monomer containing the crosslinkable functional group of the component (b), and the number of carbon atoms of the (meth)acrylic acid It is possible to use an alkyl ester having 1 to 12, more preferably an alkyl ester having 2 to 8 carbon atoms. That is, in the alkyl (meth)acrylate, if the alkyl group has a long chain form, the cohesive strength of the pressure-sensitive adhesive may be lowered. Therefore, in order to maintain the cohesive strength under high temperature, the alkyl group preferably has a carbon number of 1 to 12, and more preferably Is in the range of 2 to 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, etc. These may be mentioned, and these may be used alone or in combination of two or more.

(b) The vinyl-based monomer and the (meth)acrylic monomer containing a crosslinkable functional group of the component react with the crosslinking agent to prevent destruction of the cohesive strength of the pressure-sensitive adhesive under high temperature or high temperature and high humidity conditions. Is given. The blending amount of the monomer of the component (b) is preferably used in an amount of 0.1 to 10 parts by mass, particularly 1 to 9 parts by mass, based on 100 parts by mass of the monomer to be copolymerized, and when it is less than 0.1 parts by mass, cohesive failure under high temperature and humidity is likely to occur. In some cases, if it exceeds 10 parts by mass, the suitability decreases significantly, causing surface migration to occur, and the fluidity decreases, while the cohesive force increases, thereby reducing the stress relaxation ability.

Examples of vinyl monomers or (meth)acrylic monomers containing a crosslinkable functional group of the component (b) include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl Monomers containing hydroxyl groups such as (meth)acrylate, diethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, etc., (meth)acrylic acid, (meth)acrylic acid dimer, itaconic acid, maleic acid And a monomer containing a carboxyl group such as maleic anhydride, (meth)acryloxypropyltrimethoxysilane, (meth)acryloxypropyltriethoxysilane, (meth)acryloxypropylmethyldimethoxysilane, (meth)acryloxy Propylmethyldiethoxysilane, (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethyltriethoxysilane, (meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, etc. Monomers containing a hydrolyzable silyl group of, but are not limited thereto. The monomers may be used alone or in combination of two or more.

In addition, in the present invention, other copolymerizable monomers may be further used in order to control the glass transition temperature of the pressure-sensitive adhesive composition during production of the acrylic copolymer and to impart other functionality. 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, based on 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 of the polymer chain, the molecular weight distribution, or the amount of molecular structure, and in particular, it is determined by the molecular weight, so the molecular weight (weight average) of the (meth)acrylic copolymer used in the present invention Molecular weight: Mw) is preferably 800,000 to 2 million, more preferably 900,000 to 1.9 million. In addition, the weight average molecular weight is a standard polystyrene conversion value measured by gel permeation chromatography (GPC). If the molecular weight is too small, there is a concern that desired viscoelastic properties may not be obtained, and if the molecular weight is too large, the viscosity of the polymer becomes too high and handling property becomes difficult, and thus productivity may decrease.

Such a copolymer can be prepared through a conventional radical copolymerization process. In the present invention, the polymerization method of the polymer is not particularly limited, and can be prepared by a general method such as a solution polymerization method, a photopolymerization method, a bulk polymerization method, a suspension polymerization method, and 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 an initiator in a state in which the monomers are uniformly mixed.

(B) adhesion modifier [organic silicon compound (silane coupling agent)]

The adhesion modifier which is the main 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 hydrolyzed condensate thereof.

(Wherein, 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, A is a divalent hydrocarbon group having 6 to 10 carbon atoms, and Y is an epoxy structural group, n is an integer of 1 to 3)

As an adhesion-modifying component, a structure in which a hydrolyzable silyl group portion is partially hydrolyzed in addition to the above organosilicon compound alone, or a partially hydrolyzed condensate formed into an oligomer by condensation between molecules also exhibit the same performance. Included in the ingredients.

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

Specific examples of the monovalent hydrocarbon group having 1 to 6 carbon atoms for 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 phantom. Moreover, a phenyl group is mentioned as an aryl group. Preferably, a methyl group is preferred from the viewpoint of easiness of obtaining raw materials and productivity.

Specific examples of the divalent hydrocarbon group having 6 to 10 carbon atoms in A above include an alkylene group such as a hexylene group, a heptylene group, an octylene group, a nonylene group, and a decylene group. These may be straight or branched. Preferably, it is a linear octylene group from the easiness of obtaining a raw material. In addition, this structural part is the main structure of the present invention, and the conventional technology is generally a propylene group, and a longer chain length is an essential factor.

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 availability of raw materials.

In terms of these, as a more preferable structure of the epoxy group-containing organosilicon compound, the following general formula (2)

(Wherein, X, R, and n are the same as above)

Represented by

More preferably, X is a methyl group and n=3 from the viewpoint of easiness of obtaining raw materials and productivity.

In the pressure-sensitive adhesive composition of the present invention, 0.001 to 10 parts by mass of the (B) adhesive modifying component is blended with respect to 100 parts by mass of the acrylic polymer (A). If it is less than the above lower limit, the desired adhesive modification effect is not exhibited, and if it exceeds the upper limit, the effect is saturated and the relative cost effect decreases, as well as the effect of the adhesion improvement effect of the original silane coupling agent. It is not preferable because there is a risk of excessive initial adhesion.

[Adhesive composition]

Although the pressure-sensitive adhesive composition of the present invention contains the components (A) and (B) as essential components, it is preferable to further contain (C) a multifunctional crosslinking agent, and more specifically

(A) acrylic polymer: 100 parts by mass,

(B) adhesive modifier: 0.001 to 10 parts by mass,

(C) Multifunctional crosslinking agent: 0.01 to 10 parts by mass

It is preferable to contain.

Here, in the pressure-sensitive adhesive composition of the present invention, the multifunctional crosslinking agent of the component (C) serves to increase the cohesive strength of the pressure-sensitive adhesive by reacting with a carboxyl group or a hydroxyl group. The content of the crosslinking agent is preferably 0.01 to 10 parts by mass, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the copolymer of the component (A). If too much, cohesion is severe, and molding into a pressure-sensitive adhesive sheet or the like may be difficult, and if too small, the desired effect of improving cohesive strength may not be obtained.

An isocyanate-based, epoxy-based, aziridine-based, metal chelate-based crosslinking agent or the like can be used as the polyfunctional crosslinking agent, and among them, an isocyanate-based crosslinking agent is easy to use. As an isocyanate crosslinking agent, tolylene diisocyanate, xylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, isoform diisocyanate, tetramethylxylene diisocyanate, naphthalene diisocyanate, and reaction products of these with polyols such as trimethylolpropane (Trimethylolpropane tolylene diisocyanate adduct, etc.), etc. are mentioned.

Ethylene glycol diglycidyl ether, trimethylolpropane triglycidyl ether, N,N,N',N'-tetraglycidylethylenediamine, glycerin diglycidyl ether, glycerin triglycidyl ether , Polyglycerin polyglycidyl ether, sorbitol polyglycidyl ether, and the like.

Examples of azylidine crosslinking agents include N,N'-toluene-2,4-bis(1-azylidinecarboxside), N,N'-diphenylmethane-4,4'-bis(1-azylidinecarboxy) De), triethylene melamine, bisisoprotaloyl-1-(2-methylazylidine), tri-1-azilidinylphosphine oxide, etc. are mentioned.

Examples of the metal chelate crosslinking agent include compounds in which polyvalent metals such as aluminum, iron, zinc, tin, titanium, antimony, magnesium, and vanadium are incorporated in acetylacetone or ethyl acetoacetate.

Further, to the pressure-sensitive adhesive composition of the present invention, a tackifying resin may be further added to adjust the adhesion performance. The content thereof can be used in the range of 1 to 100 parts by mass, particularly 5 to 90 parts by mass, based on 100 parts by mass of the (A) (meth)acrylic copolymer. At this time, if it is less than 1 part by mass, the control effect may be insufficient, and if it exceeds 100 parts by mass, the compatibility or cohesiveness of the pressure-sensitive adhesive may be lowered.

Examples of tackifier resins include (hydrogenated) hydrocarbon resins, (hydrogenated) rosin resins, (hydrogenated) rosin ester resins, (hydrogenated) terpene resins, (hydrogenated) terpenephenol resins, polymerized rosin resins, and polymerized rosin Ester resin etc. can be used, and these can be used individually by 1 type or in mixture of 2 or more types.

In addition to the above components, low molecular weight substances such as plasticizers and leveling agents, epoxy resins and curing agents, etc., may be mixed and used as additional components as necessary, within the range that does not impair the object of the present invention, and ultraviolet stabilizers, antioxidants, and colorants (除色劑), reinforcing agent, filler, antifoaming agent, surfactant, etc. can be appropriately added and used according to the general purpose.

The method for producing the pressure-sensitive adhesive composition of the present invention is not particularly limited, and is obtained by mixing the aforementioned components (A) to (C) and other optional components by a conventional method. The mixing conditions are 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 polymerization of the (meth)acrylic copolymer, and the same effect is exhibited even when added during the manufacturing step of the (meth)acrylic copolymer. In addition, in the blending process of the multifunctional crosslinking agent to form a pressure-sensitive adhesive layer obtained by curing the pressure-sensitive adhesive composition, uniform coating becomes possible when the functional group crosslinking reaction of the crosslinking agent hardly occurs. After coating and drying and aging, a crosslinked structure is formed, and a pressure-sensitive 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, plastic film, paper, etc., and is applied at 25 to 150°C, 20 to 90% RH for 5 minutes to 5 hours, particularly 40 to 80°C, 25 to 60 The pressure-sensitive adhesive layer can be formed by curing at %RH for 10 minutes to 3 hours.

It is preferable to use the pressure-sensitive adhesive composition of the present invention after sufficiently removing components that cause bubbles such as volatile components and reaction residues therein. When the crosslinking density or molecular weight is excessively low, and the elastic modulus of the adhesive layer is excessively low, small bubbles existing between the adhesive layer and the adherend such as a glass plate in a high temperature state become large, forming a scattering body inside the adhesive layer. do. In addition, when the pressure-sensitive adhesive layer having an excessively large elastic modulus is used for a long period of time, a peeling phenomenon occurs at the end portion of the pressure-sensitive adhesive layer (sheet) due to an excessive crosslinking reaction.

In addition, when the optimum physical balance is considered, the crosslinking density of the pressure-sensitive adhesive layer is suitably in the range of 5 to 95% by mass, particularly 7 to 93% by mass. The crosslinking density refers to a value obtained by mass% of the amount of a portion having a crosslinked structure that is not dissolved in a solvent by a generally known method of measuring the gel content of an adhesive. At this time, if the crosslinking density of the pressure-sensitive adhesive layer is less than 5% by mass, the cohesive strength of the pressure-sensitive adhesive layer is lowered, and there is a concern that problems of adhesion durability such as bubbles or peeling may occur, and if it exceeds 95% by mass, it is not properly adhered and thus durable. There are cases where this weakens.

[Adhesive polarizing plate]

Next, an adhesive polarizing plate including an adhesive layer obtained by coating and curing the adhesive composition on one or both surfaces 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 a polarizing element, and a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on one or both surfaces of the polarizing film or polarizing element. It does not specifically limit about a polarizing film or a polarizing element which comprises a polarizing plate. Examples of polarizing films include films obtained by stretching a film containing a polyvinyl alcohol-based resin by containing a polarizing component such as iodine or a dichroic dye and stretching, and the thickness of these polarizing films is also not limited, and the thickness of these polarizing films is not limited. Can be molded.

Polyvinyl alcohol-based resins include polyvinyl alcohol, polyvinyl formal, polyvinyl acetal, and saponified products of ethylene/vinyl acetate copolymer.

In the present invention, the method of forming the pressure-sensitive adhesive layer on the polarizing film is not particularly limited, and a method of applying and drying the pressure-sensitive adhesive composition directly on the surface of the polarizing film using a bar coater or the like, and the pressure-sensitive adhesive composition once a peelable substrate After coating on the surface and drying, a method of transferring the pressure-sensitive adhesive layer formed on the surface of the releasable base material to the surface of the polarizing film, and then aging may be employed. In this case, drying is preferably 5 minutes to 5 hours at 25 to 150°C and 20 to 90% RH, and aging is preferably 5 minutes to 5 hours at 25 to 150°C and 20 to 90% RH.

In addition, the thickness of the pressure-sensitive adhesive layer is not particularly limited, but it is usually preferably 0.01 to 100 µm, and more preferably 0.1 to 50 µm. If the thickness of the pressure-sensitive adhesive layer is less than the above range, the effect as the pressure-sensitive adhesive layer may be insufficient, and if it is larger than the above range, the effect of the pressure-sensitive adhesive layer may be saturated and the cost may increase.

In addition, in the polarizing film (adhesive polarizing plate) having the pressure-sensitive adhesive layer of the present invention thus obtained, at least one layer providing additional functions such as a protective layer, a reflective layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film is laminated. can do.

Particularly, on both sides of a polarizing film having an 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 copolymers thereof A multilayer film in 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 also not particularly limited, and may be formed to a normal thickness.

[Liquid crystal display device]

The adhesive polarizing plate of the present invention can be applied to the general liquid crystal display device, and the kind 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 a liquid crystal is sealed between a pair of glass substrates.

In addition to the above-described polarizing film, the pressure-sensitive adhesive composition of the present invention is not limited to applications such as industrial sheets, especially reflective sheets, structural pressure-sensitive adhesive sheets, photographic pressure-sensitive adhesive sheets, adhesive sheets for lane marking, optical adhesive products, and electronic components, and can be used. have. In addition, it can be applied to a multi-layered laminate product, that is, a general commercial adhesive sheet product, a medical patch, an application field having the same action concept, such as for heat activation.

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 since the initial adhesion is low at the time of adhesion to glass, etc., it has excellent reworkability, and adhesion after moist heat treatment after adhesion This is sufficiently high and has excellent long-term durability.

[Example]

Hereinafter, the present invention will be described in more detail with reference to synthesis examples, examples, and comparative examples, but the present invention is not limited to these examples.

[(A) Synthesis example of acrylic polymer]

98.1 g of n-butyl acrylate (BA), 0.6 g of acrylic acid (AA), 1.3 g of 2-hydroxyethyl methacrylate (2-HEMA) in a 1 L separable flask equipped with a stirrer, reflux cooler, dropping funnel and thermometer Was put, and 100 g of ethyl acetate was added as a solvent, and it was dissolved. Thereafter, nitrogen gas bubbling was performed for 1 hour in order to remove oxygen, and nitrogen was substituted in the reaction system, and the temperature was maintained at 62°C. While stirring, 0.03 g of azobisisobutyronitrile was added as a polymerization initiator, and reacted at 62° C. for 8 hours to obtain a (meth)acrylic copolymer as a base polymer.

[Examples, Comparative Examples]

(A) acrylic polymer obtained in the synthesis example: (B) adhesion modifier: silane coupling agent represented by the following A-1 to 4 and B-1 to 3, (C) per 100 parts by mass of the (meth)acrylic copolymer As a polyfunctional crosslinking agent, trimethylolpropanetolylene diisocyanate adduct (TDI) was each mixed in the blending composition shown in Table 1 to obtain a pressure-sensitive adhesive composition.

The obtained pressure-sensitive adhesive composition was coated on a release paper and dried to obtain a 25 μm uniform pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer thus prepared was subjected to adhesive processing on an iodine-based 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 cylinder of the manufactured polarizing plate, it evaluated about the change of the adhesive force in durability, glass adhesiveness, rework resistance, heat resistance, or moist heat resistance through the evaluation test method shown below, and the results are shown in Tables 2-4. Indicated.

In addition, the abbreviations in Table 1 are as follows.

TDI: crosslinking 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 High School Co., Ltd.)

Silane B-2:

Silane B-3: alkoxysilyl-modified PO-type polyether compound at both ends

(Cyril 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 added pressure was about 5kgf/cm ³ , and the operation was performed in a clean room so that no air bubbles or foreign substances were generated.

In order to evaluate the moisture and heat resistance properties of this test piece, after allowing it to stand for 1,000 hours under conditions of 60°C/90% relative humidity, the presence or absence of bubbles or peeling was confirmed. The heat resistance characteristics were observed at 80°C/30% relative humidity for 1,000 hours, and then bubbles or peeling. In addition, before evaluating the state of the test piece, it is allowed to stand at room temperature (25°C) for 24 hours. Table 2 shows the results.

The evaluation criteria about durability evaluation are as follows.

○: No bubbles or peeling phenomenon

△: There is a slight bubble or peeling phenomenon

X: There are many air bubbles and peeling phenomenon

<Glass adhesion, change of adhesion under high temperature and high temperature and high humidity conditions>

After aging the adhesive-coated polarizing plate at room temperature (23℃/60%RH) for 7 days, the polarizing plates were cut into 1 inch×6 inch sizes, respectively, and an alkali free glass of 0.7 mm thickness using a 2 kg rubber roller Attached to. After storage at room temperature, the initial adhesion was measured after 1 hour, followed by aging at 50° C. for 4 hours, and then stored at room temperature for 1 hour and then the adhesion was measured. Table 2 shows the results.

In addition, in order to see the degree of increase in adhesion under high temperature and high temperature and high humidity conditions, after aging according to time under the conditions of 60℃/30%RH and 60℃/90%RH, respectively, it was allowed to cool at room temperature for 1 hour, and the adhesion was measured. I did. The results are shown in Tables 3 and 4.

At this time, the adhesive strength was measured using a tensile tester at a speed of 300 mm/min and an angle of 180°.

<Rework>

After attaching the adhesive-coated polarizing plate (90mm×170mm) to a glass substrate (110mm×190mm×0.7mm), 1 hour elapsed at room temperature (initial adhesion) and 50℃×4 hours aging, and allowed to cool for 1 hour at room temperature. Then, the polarizing plate was peeled off from the glass. Table 2 shows the results.

The evaluation criteria for rework property are as follows.

○: Easily re-peelable

△: Slightly difficult to peel again

×: impossible to peel, broken glass

For the polarizing plates to which the pressure-sensitive adhesives of Examples and Comparative Examples were applied, the evaluation results regarding changes in durability, glass adhesion, reworkability, and adhesion under high temperature and high temperature and humidity obtained through the above evaluation method are shown in Tables 2 to 4 below. Done.

In Comparative Example 1, there was no blending of an adhesion modifier, and sufficient adhesion was not expressed after heat curing. Comparative Example 2 is a case where an epoxysilane coupling agent, which is a conventional technology, is used, and since the epoxy-silyl linking chain of this compound is propylene, and the hydrophobicity of the whole molecule is low, the initial adhesion is too high and reworkability is not expressed. Comparative Examples 3 and 4 are conventional silane materials that contribute to rework property and adhesion after curing, but their final adhesion strength after curing is insufficient and thus reliability is insufficient. In Comparative Example 5, the effect is insufficient because there are too few components of the adhesive modifier to be used. On the other hand, in Comparative Example 6, since the amount of use was too large, unnecessary adhesion was expressed from the beginning, and reworkability was insufficient.

As described above, it is proved that the composition of the present invention is excellent in initial rework property, exhibits sufficient adhesion to glass by high temperature and high temperature and high humidity treatment, and is a pressure-sensitive adhesive composition excellent in long-term durability.

Claims (9)

(A) an acrylic polymer,
(B) the following general formula (1)

(Wherein, 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, A is a divalent hydrocarbon group having 6 to 10 carbon atoms, and Y is an epoxy structural group, n is an integer of 1 to 3)
An adhesion modifier comprising an epoxy group-containing organosilicon compound represented by and/or a partial hydrolyzate or partial hydrolyzed condensate thereof
A pressure-sensitive adhesive composition containing 0.001 to 10 parts by mass of the component (B) with respect to 100 parts by mass of the component (A). 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 epoxy group-containing organosilicon compound of the component (B) according to claim 1 or 2 is the following general formula (2)

(Wherein, X, R, and n are the same as the definition of claim 1)
Adhesive composition, characterized in that it is represented by. The method according to claim 1 or 2,
(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 including a crosslinkable functional group and/or 0.1 to 10 (meth)acrylic monomers Acrylic polymer obtained by copolymerizing parts by mass: 100 parts by mass,
(B) the adhesive modifier according to item 1 or 2: 0.001 to 10 parts by mass,
(C) Multifunctional crosslinking agent: 0.01 to 10 parts by mass
Adhesive composition comprising a. The method of claim 4, wherein the vinyl monomer or (meth)acrylic monomer containing a 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)acryloxypropyltrier Oxysilane, (meth)acryloxypropylmethyldimethoxysilane, (meth)acryloxypropylmethyldiethoxysilane, (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethyltriethoxysilane, (meth) At least one monomer selected from the group consisting of acryloxymethylmethyldimethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, (meth)acrylic acid, (meth)acrylic acid dimer, itaconic acid, maleic acid and maleic anhydride Phosphorus adhesive composition. The pressure-sensitive adhesive composition according to claim 4, wherein the multifunctional crosslinking agent of component (C) is at least one crosslinking agent selected from the group consisting of an isocyanate compound, an epoxy compound, an aziridine compound, and a metal chelate compound. An adhesive polarizing plate comprising a polarizing film and an adhesive layer formed from the adhesive composition according to claim 1 or 2 on one or both surfaces of the polarizing film. The adhesive polarizing plate according to claim 7, further comprising at least one layer selected from the group consisting of a protective layer, a reflective layer, a retardation plate, a wide viewing angle compensation film, and a brightness enhancing film. A liquid crystal display device comprising a liquid crystal cell in which a liquid crystal is enclosed between a pair of glass substrates, and a liquid crystal panel having the adhesive polarizing plate according to claim 7 adhered to one or both sides of the liquid crystal cell.