JP6615597B2 - Adhesive composition - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition useful for forming a pressure-sensitive adhesive layer having excellent durability in an optical film with a pressure-sensitive adhesive layer used for a liquid crystal display device or the like.

  An optical film typified by a polarizing plate obtained by laminating and laminating a transparent resin film on one or both sides of a polarizer is widely used as an optical member constituting an image display device such as a liquid crystal display device. An optical film such as a polarizing plate is often used by being bonded to another member (for example, a liquid crystal cell in a liquid crystal display device) via an adhesive layer (see Patent Document 1). For this reason, the optical film with an adhesive layer by which the adhesive layer was previously provided in the one surface as an optical film is known.

JP 2010-229321 A

  2. Description of the Related Art In recent years, liquid crystal display devices have been deployed in mobile device applications typified by smartphones and tablet terminals and in-vehicle device applications typified by car navigation systems. In such an application, there is a possibility that it may be exposed to a harsh environment as compared with a conventional indoor TV application.

  Durability is similarly required in the optical film with the pressure-sensitive adhesive layer constituting the liquid crystal display device or the like. That is, the pressure-sensitive adhesive layer incorporated in a liquid crystal display device or the like may be placed in a high temperature or high temperature and high humidity environment, or may be placed in an environment where high and low temperatures are repeated. The optical film is required to be able to suppress problems such as floating and peeling at the interface between the pressure-sensitive adhesive layer and the optical member to which the optical film is bonded, foaming of the pressure-sensitive adhesive layer, and the like even under these circumstances. It is also required that the optical characteristics do not deteriorate. In particular, when the optical film is a polarizing plate, the pressure-sensitive adhesive layer is required to have a higher durability performance than a general optical film due to a strong shrinkage stress in a high temperature environment. Due to the increasing demand for improving the durability of the liquid crystal display device described above, recently, the durability required for the pressure-sensitive adhesive layer has become very severe.

  Accordingly, an object of the present invention is to provide a pressure-sensitive adhesive composition capable of forming a pressure-sensitive adhesive layer exhibiting excellent durability even under such severe durability conditions.

（式中、ｎは１〜４の整数を示し、Ａ^１は水素原子又はアルキル基を示し、Ｘ^１は置換基を有していてもよいメチレン基を示し、ｎが２以上のとき、前記置換基は同一又は異なっていてもよい）
で表されるヒドロキシ基含有（メタ）アクリレート由来の構成単位と、５−ヒドロキシペンチルアクリレート由来の構成単位とを含む粘着剤組成物。
［２］（メタ）アクリル系樹脂を構成する全構成単位１００重量部に対して、式（ａ１）で表されるヒドロキシ基含有（メタ）アクリレート由来の構成単位の割合は１．５〜４．５重量部であり、５−ヒドロキシペンチルアクリレート由来の構成単位の割合は０．２５〜１．０重量部である［１］に記載の粘着剤組成物。
［３］（メタ）アクリル系樹脂は、ホモポリマーのガラス転移温度が０℃未満のアルキルアクリレート（ａ３−１）由来の構成単位と、ホモポリマーのガラス転移温度が０℃以上のアルキルアクリレート由来の構成単位（ａ３−２）とを含有するアルキルアクリレート（ａ３）由来の構成単位を含む［１］又は［２］に記載の粘着剤組成物。
［４］ホモポリマーのガラス転移温度が０℃未満のアルキルアクリレート（ａ３−１）由来の構成単位と、ホモポリマーのガラス転移温度が０℃以上のアルキルアクリレート（ａ３−２）由来の構成単位との割合（重量比）は、（ａ３−１）／（ａ３−２）＝２０／８０〜９５／５である［３］に記載の粘着剤組成物。
［５］（メタ）アクリル系樹脂の重量平均分子量は、ポリスチレン換算で、６．０×１０^５〜２．５×１０^６である［１］〜［４］のいずれかに記載の粘着剤組成物。
［６］架橋剤（Ｂ）は、芳香族イソシアネート化合物及び／又は該芳香族イソシアネート化合物の多価アルコール化合物による付加体である［１］〜［５］のいずれかに記載の粘着剤組成物。
［７］架橋剤（Ｂ）の割合は、（メタ）アクリル系樹脂（Ａ）１００重量部に対して、０．０１〜１０重量部である［１］〜［６］のいずれかに記載の粘着剤組成物。
［８］シラン化合物（Ｃ）は、下記式（ｃ１）

（式中、Ｂは、炭素数１〜２０のアルカンジイル基又は炭素数３〜２０の二価の脂環式炭化水素基を示し、前記アルカンジイル基及び前記脂環式炭化水素基を構成する−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置換されてもよく、Ｒ^１は炭素数１〜５のアルキル基を示し、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して、炭素数１〜５のアルキル基又は炭素数１〜５のアルコキシ基を示す）
で表されるシラン化合物である［１］〜［７］のいずれかに記載の粘着剤組成物。
［９］式（ｃ１）のＢは炭素数１〜１０のアルカンジイル基であり、Ｒ^１は炭素数１〜５のアルキル基であり、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して、炭素数１〜５のアルコキシ基である［８］に記載の粘着剤組成物。
［１０］シラン化合物（Ｃ）の割合は、（メタ）アクリル系樹脂（Ａ）１００重量部に対して、０．０１〜１０重量部である［１］〜［９］のいずれかに記載の粘着剤組成物。
［１１］粘着剤組成物から形成される粘着剤のゲル分率は、５０〜９５％である［１］〜［１０］のいずれかに記載の粘着剤組成物。
［１２］ガラス基板に、前記粘着剤組成物から形成される粘着剤層を貼合し、温度２３℃、相対湿度５０％の条件下２４時間後の前記粘着剤層の粘着力は、剥離速度３００ｍｍ／分において、０．５〜１０Ｎ／２５ｍｍである［１］〜［１１］のいずれかに記載の粘着剤組成物。
［１３］光学フィルムに積層される粘着剤層の形成に用いられる、［１］〜［１２］のいずれかに記載の粘着剤組成物。 As a result of intensive studies in order to solve the above problems, the present inventors have completed the present invention.
That is, the present invention includes the following.
[1] A pressure-sensitive adhesive composition comprising a (meth) acrylic resin (A), a crosslinking agent (B), and a silane compound (C),
The (meth) acrylic resin (A) is represented by the following formula (a1)

(In the formula, n represents an integer of 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, X ¹ represents a methylene group which may have a substituent, and when n is 2 or more, The substituents may be the same or different)
A pressure-sensitive adhesive composition comprising a structural unit derived from a hydroxy group-containing (meth) acrylate and a structural unit derived from 5-hydroxypentyl acrylate.
[2] The proportion of the structural unit derived from the hydroxy group-containing (meth) acrylate represented by the formula (a1) with respect to 100 parts by weight of all the structural units constituting the (meth) acrylic resin is 1.5 to 4. It is 5 weight part, The ratio of the structural unit derived from 5-hydroxypentyl acrylate is 0.25-1.0 weight part, The adhesive composition as described in [1].
[3] The (meth) acrylic resin is derived from a structural unit derived from an alkyl acrylate (a3-1) having a homopolymer glass transition temperature of less than 0 ° C. and an alkyl acrylate derived from a homopolymer having a glass transition temperature of 0 ° C. or higher. The pressure-sensitive adhesive composition according to [1] or [2], comprising a structural unit derived from an alkyl acrylate (a3) containing the structural unit (a3-2).
[4] A structural unit derived from an alkyl acrylate (a3-1) having a glass transition temperature of less than 0 ° C. of the homopolymer, and a structural unit derived from an alkyl acrylate (a3-2) having a glass transition temperature of the homopolymer of 0 ° C. or higher. The ratio (weight ratio) of the pressure-sensitive adhesive composition according to [3], wherein (a3-1) / (a3-2) = 20/80 to 95/5.
[5] The pressure-sensitive adhesive composition according to any one of [1] to [4], wherein the weight average molecular weight of the (meth) acrylic resin is 6.0 × 10 ^{5 to} 2.5 × 10 ⁶ in terms of polystyrene. Stuff.
[6] The pressure-sensitive adhesive composition according to any one of [1] to [5], wherein the crosslinking agent (B) is an adduct of an aromatic isocyanate compound and / or a polyhydric alcohol compound of the aromatic isocyanate compound.
[7] The ratio of the crosslinking agent (B) is 0.01 to 10 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A), according to any one of [1] to [6]. Adhesive composition.
[8] The silane compound (C) is represented by the following formula (c1)

(In formula, B shows a C1-C20 alkanediyl group or a C3-C20 bivalent alicyclic hydrocarbon group, and comprises the said alkanediyl group and the said alicyclic hydrocarbon group. —CH ₂ — may be substituted with —O— or —CO—, R ¹ represents an alkyl group having 1 to 5 carbon atoms, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each Independently, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is shown)
The pressure-sensitive adhesive composition according to any one of [1] to [7], which is a silane compound represented by:
[9] B in the formula (c1) is an alkanediyl group having 1 to 10 carbon atoms, R ¹ is an alkyl group having 1 to 5 carbon atoms, and R ² , R ³ , R ⁴ , R ⁵ and R ^6. Are each independently a pressure-sensitive adhesive composition according to [8], which is an alkoxy group having 1 to 5 carbon atoms.
[10] The ratio of the silane compound (C) is 0.01 to 10 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A), according to any one of [1] to [9]. Adhesive composition.
[11] The pressure-sensitive adhesive composition according to any one of [1] to [10], wherein a gel fraction of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition is 50 to 95%.
[12] A pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is bonded to a glass substrate, and the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer after 24 hours under conditions of a temperature of 23 ° C. and a relative humidity of 50% is determined by a peeling rate. The pressure-sensitive adhesive composition according to any one of [1] to [11], which is 0.5 to 10 N / 25 mm at 300 mm / min.
[13] The pressure-sensitive adhesive composition according to any one of [1] to [12], which is used for forming a pressure-sensitive adhesive layer laminated on an optical film.

  The pressure-sensitive adhesive composition of the present invention can form a pressure-sensitive adhesive layer having excellent durability even under severe durability conditions.

It is a schematic sectional drawing which shows an example of the optical film with an adhesive layer formed from the adhesive composition which concerns on this invention. FIG. 2 is a schematic cross-sectional view showing an example of the layer structure of the polarizing plate. FIG. 3 is a schematic cross-sectional view showing another example of the layer configuration of the polarizing plate. FIG. 4 is a schematic cross-sectional view showing an example of an optical laminate including an optical film with an adhesive layer formed from the adhesive composition according to the present invention. FIG. 5: is a schematic sectional drawing which shows an example of the optical laminated body containing the optical film with an adhesive layer formed from the adhesive composition which concerns on this invention. FIG. 6 is a schematic cross-sectional view showing still another example of an optical laminate including an optical film with an adhesive layer formed from the adhesive composition according to the present invention. FIG. 7: is a schematic sectional drawing which shows another example of the optical laminated body containing the optical film with an adhesive layer formed from the adhesive composition which concerns on this invention. FIG. 8: is a schematic sectional drawing which shows another example of the optical laminated body containing the optical film with an adhesive layer formed from the adhesive composition which concerns on this invention.

[1] Pressure-sensitive adhesive composition The pressure-sensitive adhesive composition of the present invention contains a (meth) acrylic resin (A), a crosslinking agent (B), and a silane compound (C).

（式中、ｎは１〜４の整数を示し、Ａ^１は水素原子又はアルキル基を示し、Ｘ^１は置換基を有していてもよいメチレン基を示し、ｎが２以上のとき、前記置換基は同一又は異なっていてもよい） [1-1] (Meth) acrylic resin (A)
The (meth) acrylic resin (A) is a polymer or copolymer having a structural unit derived from a (meth) acrylic monomer as a main component (preferably containing 50% by weight or more), and represented by the following formula (a1 And a structural unit derived from a hydroxy group-containing (meth) acrylate and a structural unit derived from 5-hydroxypentyl acrylate.

(In the formula, n represents an integer of 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, X ¹ represents a methylene group which may have a substituent, and when n is 2 or more, The substituents may be the same or different)

  That is, since the (meth) acrylic resin (A) of the present invention has hydroxyalkyl groups having predetermined different carbon chain lengths in the side chain, in the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, (meth) acrylic It is estimated that the crosslink density between the system resins can be optimized. By optimizing the cross-linking density, it is possible to form a pressure-sensitive adhesive layer with an excellent balance between hardness and softness (or having the optimum hardness), so that durability can be improved and peeling of the interface is possible even in a high-temperature environment. (Or floating) and foaming can be effectively suppressed. Moreover, even if a strong shrinkage stress is generated, the pressure-sensitive adhesive layer can effectively relieve the stress, so that white spots due to the shrinkage of the optical film (for example, the deflection plate) can be prevented. Furthermore, the reworkability (peelability) can be improved by optimizing the crosslinking density. In the present specification, the term “durability” refers to the interface between the pressure-sensitive adhesive layer and the optical member adjacent thereto, for example, in a high temperature environment, a high temperature and high humidity environment, or an environment where high and low temperatures are repeated. It refers to a characteristic that can suppress floating and peeling (sometimes referred to as peeling resistance) and a characteristic that can suppress problems such as foaming of the pressure-sensitive adhesive layer (sometimes referred to as foaming resistance). Moreover, in this invention, cohesive failure resistance means the characteristic which can suppress the cohesive failure (or tearing) of an adhesive layer.

In the formula (a1), X ¹ represents a methylene group which may have a substituent. Examples of the substituent include a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl group (eg, methyl group, ethyl group, propyl group, isopropyl group, butyl group, s-butyl group, t-butyl group). C _1-10 alkyl group such as butyl group, pentyl group, hexyl group, preferably C _1-6 alkyl group, more preferably C _1-3 alkyl group), cycloalkyl group (cyclopentyl group, cyclohexyl group, etc.) , Aryl group [phenyl group, alkylphenyl group (tolyl group, xylyl group, etc.)] aralkyl group (benzyl group, etc.), alkoxy group (for example, C _1-4 alkoxy group such as methoxy group, ethoxy group, etc.), polyoxyalkylene groups (e.g., such as dioxyethylene group), C of such cycloalkoxy groups (e.g., hexyloxy group cyclohexylene Such as _-10 cycloalkyloxy group), an aryloxy group (e.g., phenoxy group), aralkyloxy group (e.g., benzyloxy group), an alkylthio group (e.g., methylthio group, C _1-4 alkylthio group such as an ethylthio group ), Cycloalkylthio group (eg cyclohexylthio group etc.), arylthio group (eg thiophenoxy group etc.), aralkylthio group (eg benzylthio group etc.), acyl group (eg acetyl group etc.), nitro group And a cyano group. Of these, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group and the like are preferable, and an alkyl group (for example, a methyl group, an ethyl group, and the like) is particularly preferable.

A ¹ represents a hydrogen atom or an alkyl group, and the alkyl group may be an alkyl group exemplified in X ¹ (preferably a methyl group or the like).
In the formula (a1), n represents an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 2.

Specific examples of the hydroxy group-containing (meth) acrylate (a1) include 1-hydroxymethyl (meth) acrylate, 1-hydroxyethyl (meth) acrylate, 1-hydroxyheptyl (meth) acrylate, and (meth) acrylic. 1-hydroxybutyl acid, 1-hydroxy C _1-8 alkyl (meth) acrylate such as 1-hydroxypentyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate (Meth) acrylic acid 2-hydroxybutyl, (meth) acrylic acid 2-hydroxypentyl, (meth) acrylic acid 2-hydroxyhexyl (meth) acrylic acid 2-hydroxy C _2-9 alkyl; (meth) acrylic 3-hydroxypropyl acid, 3-hydroxybutyl (meth) acrylate, ( Data) acrylate, 3-hydroxypentyl, (meth) acrylate, 3-hydroxyhexyl, (meth) (meth) acrylic acid such as acrylic acid 3-hydroxy-heptyl 3-hydroxy _{C 3-10} alkyl; (meth) acrylic acid 4 (Meth) acrylic acid such as hydroxybutyl, 4-hydroxypentyl (meth) acrylate, 4-hydroxyhexyl (meth) acrylate, 4-hydroxyheptyl (meth) acrylate, 4-hydroxyoctyl (meth) acrylate 4-hydroxy C _4-11 alkyl; (meth) acrylic acid 2-chloro-2-hydroxypropyl, (meth) acrylic acid 3-chloro-2-hydroxypropyl, (meth) acrylic acid 2-hydroxy-3-phenoxypropyl, etc. Is mentioned. Among these, from the viewpoint of durability, hydroxy-containing (meth) acrylates in which n is 2, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate; Hydroxy-containing (meth) acrylates where n is 3 such as 3-hydroxypropyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate and 3-hydroxypentyl (meth) acrylate are preferred. In particular, the hydroxy-containing (meth) acrylate in which n is 2 is preferable, and among these, 2-hydroxyethyl (meth) acrylate is preferable.

  The proportion of the structural unit derived from the hydroxy group-containing (meth) acrylate represented by the formula (a1) with respect to 100 parts by weight of all the structural units constituting the (meth) acrylic resin is 1.5 to 4.5 parts by weight. The proportion of the structural unit derived from 5-hydroxypentyl acrylate (a2) is preferably 0.25 to 1.0 part by weight. Moreover, the ratio (weight ratio) between the structural unit derived from the hydroxy group-containing (meth) acrylate represented by the formula (a1) and the structural unit derived from 5-hydroxypentyl acrylate (a2) is particularly within the above range. Although it is not limited, Preferably (a1) / (a2) = 13 / 1-3 / 1 (for example, 11 / 1-3 / 1), More preferably, 9 / 1-4 / 1, Especially 7 / 1-5 / 1 may be sufficient. When it is in the above range, it is advantageous for formation of an optimal crosslinked structure, and characteristics such as durability can be improved.

  The (meth) acrylic resin (A) may contain a structural unit derived from the alkyl acrylate (a3) and a structural unit derived from the substituent-containing alkyl acrylate (a4).

  Among the alkyl acrylates (a3), examples of the alkyl acrylate (a3-1) having a glass transition temperature (Tg) of the homopolymer of less than 0 ° C. include ethyl acrylate, n- and i-propyl acrylate, n- and i- Butyl acrylate, n-pentyl acrylate, n- and i-hexyl acrylate, n-heptyl acrylate, n- and i-octyl acrylate, 2-ethylhexyl acrylate, n- and i-nonyl acrylate, n- and i- Examples thereof include linear or branched alkyl acrylates having about 2 to 12 carbon atoms in the alkyl group such as decyl acrylate and n-dodecyl acrylate. The alkyl acrylate (a3) may be an alkyl acrylate (cycloalkyl acrylate) having an alicyclic structure, but has a carbon number of 2 to 10 from the viewpoint of followability (or flexibility and adhesiveness) to the optical film. Alkyl acrylate, preferably an alkyl acrylate having 3 to 8 carbon atoms, more preferably an alkyl acrylate having 4 to 6 carbon atoms, particularly n-butyl alkyl acrylate. When n-butyl alkyl acrylate is used, the followability can be increased, and for example, it is advantageous in peeling resistance. These alkyl acrylates (a3-1) can be used alone or in combination of two or more.

  Examples of the alkyl acrylate (a3-2) whose Tg of the homopolymer is 0 ° C. or higher include methyl acrylate, cycloalkyl acrylate (for example, cyclohexyl acrylate, isobornyl acrylate), stearyl acrylate, t-butyl acrylate, etc. Methyl acrylate is particularly preferred. When methyl acrylate is used, the strength can be increased, which is advantageous for cohesive failure, for example. These alkyl acrylates (a3-2) can be used alone or in combination of two or more. The Tg of the alkyl acrylate homopolymer can be referred to literature values such as POLYMER HANDBOOK (Wiley-Interscience).

  The proportion of structural units derived from alkyl acrylate in (meth) acrylic resin (A) is 100 weights of all structural units constituting (meth) acrylic resin (A) from the viewpoints of durability and reworkability of the pressure-sensitive adhesive layer. Part by weight, for example, 40 parts by weight or more (for example, 50 to 98 parts by weight), preferably 60 parts by weight or more (for example, 70 to 95 parts by weight), and more preferably 70 parts by weight or more (for example, 80 parts by weight). ~ 90 parts by weight).

  When an alkyl acrylate having a homopolymer Tg of less than 0 ° C and an alkyl acrylate having a homopolymer Tg of 0 ° C or higher are used in combination, both cohesive fracture resistance and follow-up properties (foaming resistance and peeling resistance) can be achieved. The durability against dimensional changes of a film (for example, a polarizing plate) can be improved.

  Ratio (weight ratio) of a structural unit derived from an alkyl acrylate (a3-1) having a glass transition temperature of less than 0 ° C. and a structural unit derived from an alkyl acrylate (a3-2) having a glass transition temperature of 0 ° C. or higher. (A3-1) / (a3-2) = 20/80 to 95/5 (for example, 30/70 to 90/10), preferably 40/60 to 85/15, more preferably 55/45 75/25. When it is in the above range, the durability can be further improved. The followability improves as the proportion of the structural unit derived from the alkyl acrylate (a3-1) having a glass transition temperature of less than 0 ° C. increases. As the proportion of the structural unit derived from the alkyl acrylate (a3-2) having a glass transition temperature of 0 ° C. or higher increases, the cohesive fracture resistance improves.

Examples of the substituent-containing alkyl acrylate (a4) include an alkyl acrylate in which a substituent is introduced into the alkyl group in the alkyl acrylate (a3-1) (a hydrogen atom of the alkyl group is substituted with a substituent). . The substituent may be, for example, an aryl group (such as a phenyl group), an aryloxy group (phenoxy group), an alkoxy group (such as a methoxy group, an ethoxy group). Examples of the substituent-containing alkyl acrylate (a3-3) include, for example, alkoxyalkyl acrylate (eg, 2-methoxyethyl acrylate, ethoxymethyl acrylate, etc.), aryloxyalkyl acrylate (eg, phenoxyethyl acrylate, etc.), aryloxy polyalkylene glycol mono Examples include acrylate and polyalkylene glycol monoacrylate. These alkyl acrylates (a3-3) can be used alone or in combination of two or more. By including an alkyl acrylate containing an aromatic ring such as an aryl group or an aryloxy group, white spots of the polarizing plate during the durability test can be improved. The alkylene group of the aryloxy polyalkylene glycol monoacrylate and the polyalkylene glycol monoacrylate may be, for example, a C _1-6 alkylene group (preferably an ethylene group) such as a methylene group, an ethylene group, or a propylene group. From the viewpoint of durability of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition, the repeating unit of the oxyalkylene group may be, for example, 2 to 7, preferably 2 to 5 (particularly 2). In the present invention, the pressure-sensitive adhesive composition contains the (meth) acrylic resin (A) and the crosslinking agent (B) described later, and can form an optimal crosslinked structure (or crosslinking density), so the number of repeating units of the oxyalkylene group Even if is relatively small, good reworkability is exhibited. Specific examples include phenoxy di to hepta C _1-3 alkylene glycol acrylate such as phenoxy diethylene glycol acrylate, di to hepta C _1-3 alkylene mono acrylate such as diethylene glycol monoacrylate, and the like.

  The proportion of the structural unit derived from the substituent-containing alkyl acrylate is, for example, 0 to 30 parts by weight (for example, 1 to 25 parts by weight) with respect to 100 parts by weight of all the structural units constituting the (meth) acrylic resin (A). Preferably it is 3-20 weight part, More preferably, it is 5-15 weight part.

  The (meth) acrylic resin (A) is a simple substance other than the hydroxy group-containing (meth) acrylate (a1) and 5-hydroxypentyl acrylate (a2), the alkyl acrylate (a3), and the substituent-containing alkyl acrylate (a4). A structural unit derived from the monomer (a5) can be included. Other monomers can be used alone or in combination of two or more. As the other monomer (a5), a monomer (a5-1) having a polar functional group other than a hydroxy group, an acrylamide monomer (a5-2), a methacrylate (methacrylic acid ester) (a5- 3), a methacrylamide monomer (a5-4), a styrene monomer (a5-5), a vinyl monomer (a5-6), a single monomer having a plurality of (meth) acryloyl groups in the molecule And a monomer (a5-7).

  Examples of the monomer (a5-1) having a polar functional group other than a hydroxy group include (meth) acrylates having substituents such as carboxyl groups, substituted or unsubstituted amino groups, and heterocyclic groups such as epoxy groups. . Specifically, acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl Monomers having a heterocyclic group such as (meth) acrylate and 2,5-dihydrofuran; aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate and the like A monomer having a substituted or unsubstituted amino group; (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, carboxyalkyl (meth) acrylate (for example, carboxyethyl (meth) acrylate, Monomers are exemplified with a carboxyl group such as Rubokishipenchiru (meth) acrylate). These monomers can be used alone or in combination of two or more. In addition, it is preferable that the structural unit derived from the monomer which has an amino group is not included substantially from a viewpoint of preventing the fall of the peelability of the separate film which can be laminated | stacked on an adhesive layer. In addition, it does not contain substantially means that it is less than 1.0 weight part with respect to 100 weight part of all the structural units which comprise (meth) acrylic-type resin (A).

In the present invention, since it shows high durability even if it does not contain a structural unit derived from a monomer having a carboxy group that is considered to increase ITO corrosivity (a structural unit derived from a carboxyl group-containing (meth) acrylate). It is possible to achieve both durability and ITO corrosion resistance.
On the other hand, when a structural unit derived from a monomer having a carboxy group [a structural unit derived from a carboxyl group-containing (meth) acrylate] is contained, the durability can be further improved. In the present invention, since the durability can be effectively improved even if the proportion of the structural unit derived from the carboxyl group-containing (meth) acrylate is small, it is possible to improve the durability while suppressing the corrosion of ITO.

  The proportion of the structural unit derived from the carboxyl group-containing (meth) acrylate is, for example, 5.0 parts by weight or less (for example, 0 to 3 parts by weight), preferably 1 with respect to 100 parts by weight of the structural unit derived from (meth) acrylate. 0.0 parts by weight or less (for example, 0 to 0.8 parts by weight), more preferably 0.5 parts by weight or less (for example, 0.001 to 0.5 parts by weight), and even more preferably 0.3 parts by weight or less (for example, 0 0.005 to 0.3 parts by weight), particularly 0.2 parts by weight or less (for example, 0.01 to 0.2 parts by weight), especially 0.15 parts by weight or less (for example, 0.05 to 0.15 parts by weight). is there. If it is less than the upper limit, ITO corrosivity can be suppressed, and if it is more than the lower limit, durability can be improved.

  Examples of the acrylamide monomer (a5-2) include N-methylolacrylamide, N- (2-hydroxyethyl) acrylamide, N- (3-hydroxypropyl) acrylamide, N- (4-hydroxybutyl) acrylamide, N- (5-hydroxypentyl) acrylamide, N- (6-hydroxyhexyl) acrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, N- (3-dimethylaminopropyl) acrylamide, N- (1,1-dimethyl-3-oxobutyl) acrylamide, N- [2- (2-oxo-1-imidazolidinyl) ethyl] acrylamide, 2-acryloylamino-2-methyl-1-propanesulfonic acid, N- (Methoxymethyl) a Rilamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (1-methylethoxymethyl) acrylamide, N- (1-methylpropoxymethyl) acrylamide, N- (2-methylpropoxymethyl) acrylamide [Alias: N- (isobutoxymethyl) acrylamide], N- (butoxymethyl) acrylamide, N- (1,1-dimethylethoxymethyl) acrylamide, N- (2-methoxyethyl) acrylamide, N- (2-ethoxy Ethyl) acrylamide, N- (2-propoxyethyl) acrylamide, N- [2- (1-methylethoxy) ethyl] acrylamide, N- [2- (1-methylpropoxy) ethyl] acrylamide, N- [2- ( 2-methylpropoxy) ethyl] Acrylamide [alias: N- (2-isobutoxy-ethyl) acrylamide], N- (2-butoxyethyl) acrylamide, such as N- [2- (1,1-dimethylethoxy) ethyl] acrylamide. Of these, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide, N- (2-methylpropoxymethyl) acrylamide and the like are preferable.

  Examples of the methacrylate (methacrylic acid ester) (a5-3) include linear alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, n-octyl methacrylate, and lauryl methacrylate; i-butyl methacrylate Branched alkyl methacrylates such as 2-ethylhexyl methacrylate and i-octyl methacrylate; isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, cyclododecyl methacrylate, methyl cyclohexyl methacrylate, trimethyl cyclohexyl methacrylate, t-butyl cyclohexyl methacrylate, Mono or disi such as cyclohexyl phenyl methacrylate B alkyl methacrylate; 2-methoxyethyl methacrylate, alkoxyalkyl methacrylate such as ethoxymethyl methacrylate; and aralkyl methacrylates such as benzyl methacrylate.

  Examples of the methacrylamide monomer (a5-4) include a methacrylamide monomer corresponding to the acrylamide monomer described in (a5-2).

  Examples of the styrene monomer (a5-5) include styrene; methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, octyl styrene, and the like. Alkyl styrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; nitrostyrene; acetylstyrene; methoxystyrene; divinylbenzene, and the like.

  Examples of the vinyl monomer (a5-6) include, for example, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate and the like; halogens such as vinyl chloride and vinyl bromide Vinyl halides; vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinyl pyridine, vinyl pyrrolidone and vinyl carbazole; conjugated diene monomers such as butadiene, isoprene and chloroprene; unsaturated nitriles such as acrylonitrile and methacrylonitrile Etc.

  Examples of the monomer (a5-7) having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1 , 9-nonanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, etc. Monomers having a (meth) acryloyl group; monomers having three (meth) acryloyl groups in the molecule such as trimethylolpropane tri (meth) acrylate;

From the viewpoint of the reworkability of the pressure-sensitive adhesive layer, the (meth) acrylic resin (A) is a methacrylic monomer such as methacrylate (methacrylic acid ester) (a5-3) or methacrylamide monomer (a5-4). It is preferable that the proportion (or content) of the structural unit derived from the monomer is small. That is, the proportion of the structural unit is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, with respect to 100 parts by weight of all the structural units constituting the (meth) acrylic resin (A). In particular, it may be 1 part by weight or less.
Moreover, the ratio of the structural unit derived from the other monomer (a5) is, for example, 0 to 20 parts by weight, preferably 0 with respect to 100 parts by weight of all the structural units constituting the (meth) acrylic resin (A). It may be about 10 to 10 parts by weight (for example, 0.001 to 10 parts by weight), more preferably about 0 to 5 parts by weight (for example, 0.01 to 3 parts by weight).

The (meth) acrylic resin (A) has a weight average molecular weight (Mw) in terms of standard polystyrene by gel permeation chromatography GPC, for example, 6.0 × 10 ^{5 to} 2.5 × 10 ⁶ (for example, 8. 0 × 10 ^{5 to} 2.5 × 10 ⁶ ), preferably 1.0 × 10 ^{6 to} 2.0 × 10 ⁶ , more preferably 1.2 × 10 ^{6 to} 1.8 × 10 ⁶ (eg 1.3 × 10 ^{6 to} 1.6 × 10 ⁶ ). When the upper limit value of Mw is below, it is advantageous from the viewpoint of coating properties when the pressure-sensitive adhesive composition is applied to the substrate, and when Mw is equal to or higher than the lower limit value, the pressure-sensitive adhesive against the dimensional change of the optical film. It is advantageous for improving the followability of the layer. The molecular weight distribution represented by the ratio (Mw / Mn) between the weight average molecular weight Mw and the number average molecular weight Mn is usually 2 to 10, preferably 3 to 8, and more preferably 4 to 6.

The (meth) acrylic resin (A) preferably has a single peak in the range of 1.0 × 10 ^{3 to} 2.5 × 10 ⁶ Mw on the discharge curve in GPC. Use of the (meth) acrylic resin (A) having a peak number of 1 is advantageous for improving the durability of the pressure-sensitive adhesive layer.

“Having a single peak” in the above range of the obtained discharge curve means having only one maximum value in the range of Mw 1.0 × 10 ^{3 to} 2.5 × 10 ⁶ . In the present specification, a peak having an S / N ratio of 30 or more in the GPC emission curve is defined. The number of peaks in the GPC discharge curve and the Mw and Mn of the (meth) acrylic resin (A) can be determined according to the GPC measurement conditions described in the Examples section.

  When the (meth) acrylic resin (A) is dissolved in ethyl acetate to form a solution having a concentration of 20% by weight, the viscosity at 25 ° C. is preferably 20 Pa · s or less, preferably 0.1 to 7 Pa · s. It is more preferable that When the viscosity is within this range, it is advantageous from the viewpoint of coatability when the pressure-sensitive adhesive composition is applied to a substrate. The viscosity can be measured with a Brookfield viscometer.

  The glass transition temperature (Tg) of the (meth) acrylic resin (A) is, for example, -60 to 0 ° C (for example, -50 to -10 ° C), preferably -50 to -20 ° C, and more preferably -40 to 40 ° C. It may be −20 ° C. (for example, −40 to −25 ° C.). Within this range, it is advantageous for improving the durability. The glass transition temperature can be measured with a differential scanning calorimeter (DSC).

  The (meth) acrylic resin (A) can be produced by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method, and the solution polymerization method is particularly preferable. As the solution polymerization method, for example, a monomer and an organic solvent are mixed, a thermal polymerization initiator is added in a nitrogen atmosphere, and a temperature condition of about 40 to 90 ° C. (preferably 50 to 80 ° C.) is used. The method of stirring for about 15 hours is raised. In order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization. The monomer or thermal initiator may be added to an organic solvent.

  As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2′-azobis (2-methylpropio) Azo) compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, t-butyl hydroperoxide, benzoyl peroxide, t-butyl peroxybenzoate, cumene hydroperoxide , Diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, t-butyl peroxy Organic peroxides such as decanoate, t-butyl peroxypivalate, (3,5,5-trimethylhexanoyl) peroxide; inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide . Moreover, the redox initiator etc. which used the peroxide and the reducing agent together can also be used.

  The ratio of the polymerization initiator is about 0.001 to 5 parts by weight with respect to 100 parts by weight of the total amount of monomers constituting the (meth) acrylic resin. For the polymerization of the (meth) acrylic resin, a polymerization method using active energy rays (for example, ultraviolet rays) may be used.

  Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. And the like.

[1-2] Crosslinking agent (B)
The pressure-sensitive adhesive composition contains a crosslinking agent (B). The crosslinking agent (B) reacts with a polar functional group containing a hydroxy group in the (meth) acrylic resin (A). In the present invention, the OH group (hydroxyl group) of a hydroxyalkyl group having a predetermined different carbon chain introduced into the side chain of the (meth) acrylic resin (A) reacts with the crosslinking agent (B), resulting in durability. And a cross-linked structure advantageous for reworkability is formed.

  Examples of the crosslinking agent (B) include conventional crosslinking agents (for example, isocyanate compounds, epoxy compounds, aziridine compounds, metal chelate compounds, peroxides, etc.), and in particular, the pot life of the pressure-sensitive adhesive composition and the pressure-sensitive adhesive layer attached. From the viewpoint of the durability of the optical film, the crosslinking rate, etc., an isocyanate compound is preferable.

  As the isocyanate compound, a compound having at least two isocyanato groups (—NCO) in the molecule is preferable. For example, an aliphatic isocyanate compound (eg, hexamethylene diisocyanate), an alicyclic isocyanate compound (eg, isophorone diisocyanate). ), Aromatic isocyanate compounds (for example, tolylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc.). The crosslinking agent (B) is an adduct (adduct) of the isocyanate compound with a polyhydric alcohol compound [for example, an adduct with glycerol, trimethylolpropane or the like], an isocyanurate, a burette type compound, a polyether polyol, or a polyester. It may be a derivative such as a urethane prepolymer type isocyanate compound obtained by addition reaction with a polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol or the like. A crosslinking agent (B) can be used individually or in combination of 2 or more types. Of these, typically aromatic isocyanate compounds (for example, tolylene diisocyanate, xylylene diisocyanate), aliphatic isocyanate compounds (for example, hexamethylene diisocyanate) or their polyhydric alcohol compounds (glycerol, trimethylolpropane). Examples include adducts. If the cross-linking agent (B) is an adduct of an aromatic isocyanate compound and / or these polyhydric alcohol compounds, it may be advantageous for the formation of an optimal cross-linking density (or cross-linked structure). Can be improved. In particular, when it is an adduct of a tolylene diisocyanate compound and / or a polyhydric alcohol compound thereof, durability (for example, durability when an adhesive layer is applied to an ITO substrate) can be further improved.

The ratio of the crosslinking agent (B) is, for example, 0.01 to 10 parts by weight (eg 0.05 to 5 parts by weight), preferably 0.1 to 100 parts by weight of the (meth) acrylic resin (A). It may be 3 parts by weight (for example, 0.1 to 2 parts by weight), more preferably 0.2 to 1 part by weight (for example, 0.3 to 0.8 parts by weight). When it is at most the upper limit value, it is advantageous for improving followability (or peeling resistance), and when it is at least the lower limit value, it is advantageous for improving cohesion resistance (or foam resistance) and reworkability.

[1-3] Silane compound (C)
The pressure-sensitive adhesive composition contains a silane compound (C). By including the silane compound (C), adhesion (or adhesiveness) between the pressure-sensitive adhesive layer and the metal layer, the transparent electrode, the glass substrate, or the like can be improved. The silane compound (C) may be any silane compound that can be bonded to the reactive group (for example, OH group of hydroxyl group) of the (meth) acrylic resin (A). For example, vinyltrimethoxysilane, vinyltriethoxy Silane, vinyltris (2-methoxyethoxy) silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 1 , - bis (3'-trimethoxy propyl) urea and the like.

  The silane compound (C) may be a silicone oligomer type compound. When the silicone oligomer is represented by a combination of monomers, for example, 3-mercaptopropyldi or trimethoxysilane-tetramethoxysilane oligomer, 3 -Mercaptoalkyl group-containing oligomers such as mercaptomethyldi or trimethoxysilane-tetraethoxysilane oligomer, 3-mercaptopropyldi or triethoxysilane-tetramethoxysilane oligomer, 3-mercaptomethyldi or triethoxysilane-tetraethoxysilane oligomer The mercaptoalkyl group of the mercaptoalkyl group-containing oligomer is substituted with other substituents [3-glycidoxypropyl group, (meth) acryloyloxypropyl group, vinyl group, amino group, etc.] Such as the replacement oligomer, and the like.

  The silane compound (C) may preferably be a silane compound represented by the following formula (c1). When the pressure-sensitive adhesive composition contains a silane compound represented by the following formula (c1), the adhesiveness (or adhesiveness) can be further improved, so that a pressure-sensitive adhesive layer having excellent peeling resistance can be formed. Furthermore, the pressure-sensitive adhesive layer is excellent in reworkability. In particular, even when the pressure-sensitive adhesive layer is applied (or laminated) to a transparent electrode (for example, an ITO substrate) in a high-temperature environment, adhesion (or adhesiveness) can be maintained and high durability can be exhibited.

（式中、Ｂは、炭素数１〜２０のアルカンジイル基又は炭素数３〜２０の二価の脂環式炭化水素基を示し、前記アルカンジイル基及び前記脂環式炭化水素基を構成する−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置換されてもよく、Ｒ^１は炭素数１〜５のアルキル基を示し、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５及びＲ^６はそれぞれ独立して、炭素数１〜５のアルキル基又は炭素数１〜５のアルコキシ基を示す）

(In formula, B shows a C1-C20 alkanediyl group or a C3-C20 bivalent alicyclic hydrocarbon group, and comprises the said alkanediyl group and the said alicyclic hydrocarbon group. —CH ₂ — may be substituted with —O— or —CO—, R ¹ represents an alkyl group having 1 to 5 carbon atoms, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each Independently, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is shown)

In the formula (c1), B represents an alkanediyl group having 1 to 20 carbon atoms such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group; a cyclobutylene group (for example, 1,2-cyclobutylene group), cyclopentylene group (for example, 1,2-cyclopentylene group), cyclohexylene group (for example, 1,2-cyclohexylene group), cyclooctylene group (for example, 1,2- A divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms such as a cyclooctylene group; or —CH ₂ — constituting these alkanediyl groups and the alicyclic hydrocarbon group is —O— or The group substituted by -CO- is shown. Preferred B is an alkanediyl group having 1 to 10 carbon atoms. R ¹ represents an alkyl group having 1 to 5 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an s-butyl group, a t-butyl group, or a pentyl group, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkyl group having 1 to 5 carbon atoms exemplified for R ¹ ; or methoxy group, ethoxy group, propoxy group, i-propoxy group, butoxy group, s-butoxy group And an alkoxy group having 1 to 5 carbon atoms such as a t-butoxy group. Preferred R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are alkoxy groups having 1 to 5 carbon atoms. These silane compounds (C) can be used alone or in combination of two or more.

Specific examples of the silane compound (c1) include (trimethoxysilyl) methane, 1,2-bis (trimethoxysilyl) ethane, 1,2-bis (triethoxysilyl) ethane, 1,3-bis ( Trimethoxysilyl) propane, 1,3-bis (triethoxysilyl) propane, 1,4-bis (trimethoxysilyl) butane, 1,4-bis (triethoxysilyl) butane, 1,5-bis (trimethoxy) Silyl) pentane, 1,5-bis (triethoxysilyl) pentane, 1,6-bis (trimethoxysilyl) hexane, 1,6-bis (triethoxysilyl) hexane, 1,6-bis (tripropoxysilyl) Hexane, 1,8-bis (trimethoxysilyl) octane, 1,8-bis (triethoxysilyl) octane, 1,8-bis (tripropo Shishiriru) bis octane (tri _{C 1-5 alkoxysilyl) C 1-10} alkanes, bis (dimethoxymethylsilyl) methane, 1,2-bis (dimethoxymethylsilyl) ethane, 1,2-bis (dimethoxy ethyl silyl ) Ethane, 1,4-bis (dimethoxymethylsilyl) butane, 1,4-bis (dimethoxyethylsilyl) butane, 1,6-bis (dimethoxymethylsilyl) hexane, 1,6-bis (dimethoxyethylsilyl) hexane Bis (diC _1-5 alkoxyC _1-5 alkylsilyl) C _1-10 alkanes such as 1,8-bis (dimethoxymethylsilyl) octane, 1,8-bis (dimethoxyethylsilyl) octane; -Bis (methoxydimethylsilyl) hexane, 1,8-bis (methoxydimethylsilyl) octane And bis (mono C _1-5 alkoxy-diC _1-5 alkylsilyl) C _1-10 alkane. Of these, 1,2-bis (trimethoxysilyl) ethane, 1,3-bis (trimethoxysilyl) propane, 1,4-bis (trimethoxysilyl) butane, 1,5-bis (trimethoxysilyl) Bis (triC _1-3 alkoxysilyl) C _1-10 alkanes such as pentane, 1,6-bis (trimethoxysilyl) hexane, 1,8-bis (trimethoxysilyl) octane are preferred, especially 1,6 -Bis (trimethoxysilyl) hexane and 1,8-bis (trimethoxysilyl) octane are preferred.

  The ratio of the silane compound (C) is, for example, 0.01 to 10 parts by weight (for example, 0.03 to 5 parts by weight), preferably 0.05 with respect to 100 parts by weight of the (meth) acrylic resin (A). -3 parts by weight, more preferably 0.1-1 part by weight (for example, 0.2-0.5 part by weight). If it is below the upper limit, it is advantageous for suppressing bleeding out of the silane compound (C) from the pressure-sensitive adhesive layer, and if it is above the lower limit, the adhesiveness between the pressure-sensitive adhesive layer and the metal layer or glass substrate ( (Or adhesiveness) is easy to improve, which is advantageous in improving peeling resistance.

[1-4] Antistatic agent The pressure-sensitive adhesive composition may further contain an antistatic agent. By including the antistatic agent, the antistatic property of the pressure-sensitive adhesive can be improved (for example, a problem caused by static electricity generated when a release film, a protective film, or the like is peeled off) can be suppressed. Examples of the antistatic agent include conventional ones, and an ionic antistatic agent is preferable. Examples of the cation component constituting the ionic antistatic agent include organic cations and inorganic cations. Examples of the organic cation include a pyridinium cation, an imidazolium cation, an ammonium cation, a sulfonium cation, and a phosphonium cation. Examples of the inorganic cation include alkali metal cations such as lithium cation, potassium cation, sodium cation and cesium cation, and alkaline earth metal cations such as magnesium cation and calcium cation. The anionic component constituting the ionic antistatic agent may be either an inorganic anion or an organic anion, but an anionic component containing a fluorine atom is preferred from the viewpoint of excellent antistatic performance. Examples of the anion component containing a fluorine atom include hexafluorophosphate anion (PF _6- ), bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N-], bis (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N-], tetra (pentafluorophenyl) borate anion [(C ₆ F ₅ ) ₄ B-] and the like. These antistatic agents can be used alone or in combination of two or more. In particular, bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ₂ N—], bis (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N—], tetra (pentafluorophenyl) borate anion [(C ₆ F5) ₄ B-] is preferred.
An ionic antistatic agent that is solid at room temperature is preferable in that the antistatic performance of the pressure-sensitive adhesive composition is excellent over time.
The proportion of the antistatic agent is, for example, 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, and more preferably 1 to 3 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin (A). It may be.

[1-5] Other components The pressure-sensitive adhesive composition comprises a solvent, a crosslinking catalyst, an ultraviolet absorber, a weathering stabilizer, a tackifier, a plasticizer, a softening agent, a dye, a pigment, an inorganic filler, light scattering fine particles, and the like. An agent can be contained alone or in combination of two or more. It is also useful to blend an ultraviolet curable compound into the pressure-sensitive adhesive composition and form a pressure-sensitive adhesive layer and then cure it by irradiating with ultraviolet rays to form a harder pressure-sensitive adhesive layer. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin.

  The pressure-sensitive adhesive composition can contain a rust preventive agent from the viewpoint of enhancing the metal corrosion resistance of the pressure-sensitive adhesive layer. Examples of the rust inhibitor include triazole compounds such as benzotriazole compounds; thiazole compounds such as benzothiazole compounds; imidazole compounds such as benzylimidazole compounds; imidazoline compounds; quinoline compounds; pyridine compounds; Examples thereof include pyrimidine compounds; indole compounds; amine compounds; urea compounds; sodium benzoates; benzyl mercapto compounds; di-sec-butyl sulfide; and diphenyl sulfoxide.

[2] Structure and production method of pressure-sensitive adhesive layer and optical film with pressure-sensitive adhesive layer The pressure-sensitive adhesive composition of the present invention forms a pressure-sensitive adhesive layer by performing surface activation treatment (for example, plasma treatment, corona treatment, etc.). it can. Usually, the pressure-sensitive adhesive layer is laminated on at least one surface of the optical film.
FIG. 1 is a schematic cross-sectional view showing an example of an optical film with an adhesive layer formed from the adhesive composition according to the present invention. The optical film 1 with an adhesive layer shown in FIG. 1 is an optical film having an optical film 10 and an adhesive layer 20 laminated on one side of the optical film. The pressure-sensitive adhesive layer 20 is usually laminated directly on the surface of the optical film 10. The pressure-sensitive adhesive layer 20 may be laminated on both surfaces of the optical film 10.
When laminating the pressure-sensitive adhesive layer 20 on the surface of the optical film 10, a primer layer is formed on the bonding surface of the optical film 10 and / or the bonding surface of the pressure-sensitive adhesive layer 20, or the surface activation treatment ( For example, plasma treatment, corona treatment and the like are preferably performed, and corona treatment is particularly preferable.

  When the optical film 10 is a single-sided protective polarizing plate as shown in FIG. 2, the pressure-sensitive adhesive layer 20 is usually laminated on the polarizer surface, that is, the surface of the polarizer 2 opposite to the first resin film 3. (Preferably directly laminated). When the optical film 10 is a double-sided protective polarizing plate as shown in FIG. 3, the pressure-sensitive adhesive layer 20 may be laminated on the outer surface of either the first or second resin film 3 or 4, and both outer surfaces May be laminated.

  A separate antistatic layer may be provided between the optical film 10 and the pressure-sensitive adhesive layer 20. As the antistatic layer, silicon materials such as polysiloxane, inorganic metal materials such as tin-doped indium oxide and tin-doped antimony oxide, and organic polymer materials such as polythiophene, polystyrene sulfonic acid, and polyaniline can be used.

  The optical film 1 with an adhesive layer may include a separate film (release film) laminated on the outer surface of the adhesive layer 20. This separate film is usually peeled and removed when the pressure-sensitive adhesive layer 20 is used (for example, when laminated on a transparent conductive electrode or a glass substrate). The separate film is obtained by, for example, performing a release treatment such as a silicone treatment on the surface on which the adhesive layer 20 of a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarate is formed. Also good.

  The optical film 1 with the pressure-sensitive adhesive layer is obtained by dissolving or dispersing each component constituting the pressure-sensitive adhesive composition in a solvent to obtain a solvent-containing pressure-sensitive adhesive composition, and then applying and drying this onto the surface of the optical film 10. And can be obtained by forming the pressure-sensitive adhesive layer 20. Moreover, the optical film 1 with an adhesive layer forms the adhesive layer 20 on the mold release process surface of a separate film similarly to the above, and laminates | transfers this adhesive layer 20 on the surface of the optical film 10 (transfer). Can also be obtained.

  The thickness of the pressure-sensitive adhesive layer is usually 2 to 40 μm. From the viewpoint of durability of the optical film with the pressure-sensitive adhesive layer and reworkability of the optical film with the pressure-sensitive adhesive layer, it is preferably 5 to 30 μm, and more preferably 10 ˜25 μm. When the amount is not more than the upper limit value, the followability (or followability) of the pressure-sensitive adhesive layer with respect to the dimensional change of the optical film becomes good, and when it is not less than the lower limit value, the reworkability becomes good.

  The pressure-sensitive adhesive layer preferably exhibits a storage elastic modulus of 0.1 to 5 MPa in a temperature range of 23 to 80 ° C. Thereby, durability of the optical film with an adhesive layer can be improved more effectively. “Shows a storage elastic modulus of 0.1 to 5 MPa in a temperature range of 23 to 80 ° C.” means that the storage elastic modulus is a value within the above range at any temperature within this range. Since the storage elastic modulus usually decreases gradually as the temperature rises, if both the storage elastic modulus at 23 ° C. and 80 ° C. are within the above range, the storage elastic modulus within the above range is exhibited at the temperature in this range. Can be assumed. The storage elastic modulus of the pressure-sensitive adhesive layer can be measured using a commercially available viscoelasticity measuring device, for example, a viscoelasticity measuring device “DYNAMIC ANALYZER RDA II” manufactured by REOMETRIC.

  The gel fraction can be used as an index of the crosslinking density. Since the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has a predetermined cross-linking density, it exhibits a predetermined gel fraction. That is, the gel fraction of the pressure-sensitive adhesive layer is, for example, 50 to 95% by weight (for example 55 to 93% by weight), preferably 60 to 90% by weight (for example 65 to 90% by weight), and more preferably 70 to 85%. % By weight (for example, 80 to 85% by weight) may be used. When the gel fraction is at least the lower limit, it is advantageous for foaming resistance (cohesive fracture resistance) and reworkability of the pressure-sensitive adhesive layer, and when the gel fraction is at most the upper limit, it is advantageous for peeling resistance. . The gel fraction can be measured by the method described in the Examples section.

  The pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition of the present invention has a predetermined pressure-sensitive adhesive force. That is, the pressure-sensitive adhesive layer is bonded to a glass substrate, and the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer after 24 hours under the conditions of a temperature of 23 ° C. and a relative humidity of 50% is, for example, 0. 5-25N (for example, 0.5-20N), Preferably it is 0.5-10N (for example, 1-10N), More preferably, 1-8N may be sufficient. When the adhesive strength is at least the lower limit, the adhesiveness (or adhesiveness) is improved, which is advantageous for peeling resistance, and when the adhesive strength is at most the upper limit, it is advantageous for reworkability. The adhesive strength can be measured by the method described in the Examples section.

[2-1] Optical Film The optical film 10 constituting the optical film 1 with the pressure-sensitive adhesive layer may be various optical films (films having optical characteristics) that can be incorporated in an image display device such as a liquid crystal display device. . The optical film 10 may have a single layer structure (for example, an optical functional film such as a polarizer, a retardation film, a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, a light collecting film, etc.) A multilayer structure (for example, a polarizing plate, a phase difference plate, etc.) may be used. The optical film 10 is preferably a polarizing plate, a polarizer, a retardation plate or a retardation film, and particularly preferably a polarizing plate or a polarizer. In the present specification, the optical film means a film that functions for image display (display screen or the like) (for example, a film that functions for improving the visibility of an image). Further, in the present specification, the polarizing plate means that a resin film or a resin layer is laminated on at least one surface of a polarizer, and the retardation plate means a resin film on at least one surface of the retardation film. Or the thing on which the resin layer was laminated | stacked is meant.

[2-2] Polarizing Plate FIGS. 2 and 3 are schematic cross-sectional views showing examples of the layer configuration of the polarizing plate. The polarizing plate 10a shown in FIG. 2 is a single-sided protective polarizing plate in which the first resin film 3 is laminated (or laminated) on one surface of the polarizer 2, and the polarizing plate 10b shown in FIG. This is a double-sided protective polarizing plate in which the second resin film 4 is further laminated (or laminated) on the other surface of the polarizer 2. The first and second resin films 3 and 4 can be bonded to the polarizer 2 via an adhesive layer and an adhesive layer (not shown). The polarizing plates 10a and 10b may include other films and layers other than the first and second resin films 3 and 4.

  The polarizer 2 is a film having a property of absorbing linearly polarized light having a vibration surface parallel to the absorption axis and transmitting linearly polarized light having a vibration surface orthogonal to the absorption axis (parallel to the transmission axis). A film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film can be used. Examples of the dichroic dye include iodine and dichroic organic dyes.

  The polyvinyl alcohol-based resin can be obtained by saponifying a polyvinyl acetate-based resin. Examples of the polyvinyl acetate resin include polyvinyl acetate which is a homopolymer of vinyl acetate, and a monomer copolymerizable with vinyl acetate (for example, unsaturated carboxylic acid, olefin, vinyl ether, unsaturated sulfonic acid, ammonium group). (Meth) acrylamide etc.) and vinyl acetate.

  The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, for example, polyvinyl formal or polyvinyl acetal modified with aldehydes. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol resin can be determined according to JIS K 6726.

  Usually, what formed the polyvinyl alcohol-type resin into a film is used as a raw film of the polarizer 2. A polyvinyl alcohol-type resin can be formed into a film by a well-known method. The thickness of the raw film is usually 1 to 150 μm, and preferably 10 μm or more in consideration of easiness of stretching.

  The polarizer 2 is, for example, a step of uniaxially stretching the original film, a step of dyeing the film with a dichroic dye and adsorbing the dichroic dye, a step of treating the film with an aqueous boric acid solution, and The film is washed with water and finally dried. The thickness of the polarizer 2 is usually 1 to 30 μm, and is preferably 20 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less from the viewpoint of thinning the optical film 1 with an adhesive layer.

A polarizer 2 formed by adsorbing and orienting a dichroic dye on a polyvinyl alcohol-based resin film is as follows: 1) A single film of a polyvinyl alcohol-based resin film is used as a raw film, and this film is uniaxially stretched and dichroic. In addition to the method of dyeing dyes, 2) A base film having a polyvinyl alcohol resin layer was obtained by applying a coating liquid (such as an aqueous solution) containing a polyvinyl alcohol resin to the base film and drying it. Thereafter, this can also be obtained by uniaxially stretching the whole base film, subjecting the stretched polyvinyl alcohol resin layer to a dichroic dye dyeing process, and then peeling and removing the base film. As the base film, a film made of a thermoplastic resin similar to the thermoplastic resin that can constitute the first and second resin films 3 and 4 described later can be used, and preferably a polyester-based resin such as polyethylene terephthalate. , Polycarbonate resins, cellulose resins such as triacetyl cellulose, cyclic polyolefin resins such as norbornene resins, polystyrene resins, and the like. When the method 2) is used, the thin film polarizer 2 can be easily manufactured. For example, the polarizer 2 having a thickness of 7 μm or less can be easily manufactured.

  The first and second resin films 3 and 4 are each independently a light-transmitting, preferably optically transparent thermoplastic resin such as a chain polyolefin resin (polyethylene resin, polypropylene resin, etc.). Polyolefin resins such as cyclic polyolefin resins (norbornene resins, etc.); cellulose resins (cellulose ester resins, etc.); polyester resins (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, etc.); polycarbonate resins (for example, , Polycarbonates derived from bisphenols such as 2,2-bis (4-hydroxyphenyl) propane, etc.); (meth) acrylic resins; polystyrene resins; polyetheretherketone resins; polysulfone resins or mixtures thereof , It may be a film made of polymer. Among these, the first and second resin films 3 and 4 are films composed of a cyclic polyolefin resin, a polycarbonate resin, a cellulose resin, a polyester resin, a (meth) acrylic resin, and the like, respectively. In particular, a film composed of a cellulose resin and a cyclic polyolefin resin is preferable.

  Examples of the chain polyolefin resin include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins.

  Cyclic polyolefin-based resin is a general term for resins containing, as polymerized units, cyclic olefins typically represented by norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene) or their derivatives. Cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins and hydrogenated products thereof, addition polymers of cyclic olefins, cyclic olefins and chain olefins such as ethylene and propylene, and aromatic compounds having a vinyl group And a modified (co) polymer obtained by modifying these with an unsaturated carboxylic acid or a derivative thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferred.

  The cellulose-based resin is preferably a cellulose ester-based resin, that is, a cellulose partial or completely esterified product, and examples thereof include cellulose acetate, propionate, butyrate, and mixed esters thereof. Of these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferable.

  The polyester-based resin is a resin other than the cellulose ester-based resin having an ester bond, and is generally made of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate.

  The polycarbonate-based resin is a polyester formed from carbonic acid and glycol or bisphenol. Among these, from the viewpoint of heat resistance, weather resistance, and acid resistance, an aromatic polycarbonate having a diphenylalkane in the molecular chain is preferable. Examples of the polycarbonate include 2,2-bis (4-hydroxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, , 1-bis (4-hydroxyphenyl) isobutane, polycarbonate derived from bisphenols such as 1,1-bis (4-hydroxyphenyl) ethane, and the like.

The (meth) acrylic resin that can constitute the first and second resin films 3 and 4 can be a polymer mainly composed of a structural unit derived from a methacrylic ester (for example, containing 50% by weight or more). The copolymer is preferably a copolymer in which another copolymer component is copolymerized. The (meth) acrylic resin may contain two or more structural units derived from methacrylic acid esters. Examples of the methacrylic acid ester include C _{1 to} C ₄ alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

Examples of the copolymer component that can be copolymerized with the methacrylic acid ester include acrylic acid esters. Acrylic acid ester is preferably methyl acrylate, ethyl acrylate, butyl acrylate, C ₁ -C ₈ alkyl esters of acrylic acid such as 2-ethylhexyl acrylate. Specific examples of other copolymer components include unsaturated acids such as (meth) acrylic acid; aromatic vinyl compounds such as styrene, halogenated styrene, α-methylstyrene, and vinyl toluene; vinylcyan such as (meth) acrylonitrile. Compound; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; unsaturated imides such as phenylmaleimide and cyclohexylmaleimide, etc. other than acrylic acid ester having one polymerizable carbon-carbon double bond in the molecule The compound of this is mentioned. A compound having two or more polymerizable carbon-carbon double bonds in the molecule may be used as a copolymerization component. A copolymerization component can be used individually or in combination of 2 or more types.

  The (meth) acrylic resin may have a ring structure in the polymer main chain in that the durability of the film can be improved. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, or a lactone ring structure. Specific examples of the cyclic acid anhydride structure include a glutaric anhydride structure and a succinic anhydride structure, and specific examples of the cyclic imide structure include a glutarimide structure and a succinimide structure. Examples include butyrolactone ring structure and valerolactone ring structure.

The (meth) acrylic resin may contain acrylic rubber particles from the viewpoints of film-formability on the film and impact resistance of the film. Acrylic rubber particles are particles having an elastic polymer mainly composed of an acrylate ester as an essential component. The acrylic rubber particles have a single-layer structure consisting essentially of this elastic polymer, or an elastic polymer in one layer. And a multilayer structure having Examples of the elastic polymer include a cross-linked elastic copolymer obtained by copolymerizing an alkyl acrylate as a main component with another vinyl monomer and a cross-linkable monomer copolymerizable therewith. Examples of the alkyl acrylate as the main component of the elastic polymer include C ₁ -C ₈ alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. The number of carbon atoms of the alkyl group is preferably 4 or more.

  Examples of other vinyl monomers copolymerizable with alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid such as methyl methacrylate. Examples thereof include aromatic vinyl compounds such as esters and styrene, vinylcyan compounds such as (meth) acrylonitrile, and the like. Examples of the crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate, butanediol di ( Examples include (meth) acrylates of polyhydric alcohols such as (meth) acrylate, alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate, and divinylbenzene.

  The content of the acrylic rubber particles is preferably 5 parts by weight or more, more preferably 10 parts by weight or more with respect to 100 parts by weight of the (meth) acrylic resin. When the content of the acrylic rubber particles is too large, the surface hardness of the film is lowered, and when the film is subjected to surface treatment, the solvent resistance against the organic solvent in the surface treatment agent can be lowered. Accordingly, the content of the acrylic rubber particles is usually 80 parts by weight or less, preferably 60 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic resin.

  The 1st, 2nd resin films 3 and 4 can contain the usual additive in the technical field of the present invention. Examples of the additive include an ultraviolet absorber, an infrared absorber, an organic dye, a pigment, an inorganic dye, an antioxidant, an antistatic agent, a surfactant, a lubricant, a dispersant, and a heat stabilizer. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, triazine compounds, cyano (meth) acrylate compounds, nickel complex salts, and the like.

  Each of the first and second resin films 3 and 4 may be an unstretched film or a uniaxially or biaxially stretched film. The first resin film 3 and / or the second resin film 4 may be a protective film that plays a role of protecting the polarizer 2, or may be a protective film having an optical function such as a retardation film described later. Good. The first resin film 3 and the second resin film 4 may be the same or different films.

  The first resin film 3 and / or the second resin film 4 has a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, and an antistatic layer on the outer surface (the surface opposite to the polarizer 2). Further, a surface treatment layer (coating layer) such as an antifouling layer or a conductive layer may be provided. The thicknesses of the first resin film 3 and the second resin film 4 are usually 1 to 150 μm, preferably 5 to 100 μm (for example, 5 to 60 μm), more preferably 50 μm or less (for example, 1 to 40 μm), It may be 30 μm or less (for example, 5 to 25 μm).

  In particular, a polarizing plate for small and medium-sized devices such as smartphones and tablet terminals is often used as a thin film having a thickness of 30 μm or less as the first resin film 3 and / or the second resin film 4 because of the demand for thinning. Such a polarizing plate has a weak force to suppress the contraction force of the polarizer 2 and tends to have insufficient durability. Even when such a polarizing plate is used as the optical film 10, the optical film 1 with the pressure-sensitive adhesive layer of the present invention has good durability.

The first and second resin films 3 and 4 can be bonded to the polarizer 2 via an adhesive layer or an adhesive layer. As an adhesive forming the adhesive layer, a water-based adhesive or an active energy ray-curable adhesive can be used.

  As the water-based adhesive, a conventional water-based adhesive (for example, an adhesive comprising a polyvinyl alcohol resin aqueous solution, an aqueous two-component urethane emulsion adhesive, an aldehyde compound, an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, And crosslinking agents such as amine compounds and polyvalent metal salts). Among these, a water-based adhesive made of a polyvinyl alcohol-based resin aqueous solution can be suitably used. In addition, when using a water-system adhesive, after bonding the polarizer 2 and the 1st, 2nd resin films 3 and 4, it implements the process dried to remove the water contained in a water-system adhesive It is preferable to do. After the drying process, for example, a curing process for curing at a temperature of about 20 to 45 ° C. may be provided.

  The active energy ray-curable adhesive refers to an adhesive that cures when irradiated with active energy rays such as ultraviolet rays and electron beams. For example, a curable composition containing a polymerizable compound and a photopolymerization initiator, light Examples thereof include a curable composition containing a reactive resin, a curable composition containing a binder resin and a photoreactive cross-linking agent, and preferably an ultraviolet curable adhesive.

  When an active energy ray-curable adhesive is used, after the polarizer 2 and the first and second resin films 3 and 4 are bonded, a drying process is performed as necessary, and then an active energy ray is irradiated. A curing step of curing the active energy ray-curable adhesive is performed. The light source of the active energy ray is not particularly limited, but ultraviolet light having a light emission distribution at a wavelength of 400 nm or less is preferable.

  As a method of laminating the polarizer 2 and the first and second resin films 3 and 4, surface activation treatment such as saponification treatment, corona treatment, plasma treatment, etc. is applied to at least one of these lamination surfaces. The method of giving is mentioned. When a resin film is bonded to both surfaces of the polarizer 2, the adhesive for bonding these resin films may be the same type of adhesive or a different type of adhesive.

  The polarizing plates 10a and 10b can further include other films or layers. Specific examples thereof include a retardation film, a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, a condensing film, an adhesive layer other than the adhesive layer 20, a coating layer, a protective film, and the like. . The protective film is a film used for the purpose of protecting the surface of the optical film 10 such as a polarizing plate from scratches and dirt. After the optical film 1 with an adhesive layer is bonded onto, for example, a metal layer or a substrate, it is peeled off. It is customary to be removed.

  The protective film is usually composed of a base film and a pressure-sensitive adhesive layer laminated thereon. The base film is composed of a thermoplastic resin, for example, a polyolefin resin such as polyethylene resin or polypropylene resin; a polyester resin such as polyethylene terephthalate or polyethylene naphthalate; a polycarbonate resin; a (meth) acrylic resin, or the like. be able to.

[2-3] Phase difference plate The phase difference film contained in the phase difference plate is an optical film exhibiting optical anisotropy as described above, and can be used for the first and second resin films 3 and 4. In addition to the thermoplastic resins exemplified above, for example, polyvinyl alcohol resins, polyarylate resins, polyimide resins, polyether sulfone resins, polyvinylidene fluoride / polymethyl methacrylate resins, liquid crystal polyester resins, It can be a stretched film obtained by stretching a resin film made of an ethylene-vinyl acetate copolymer saponified product, a polyvinyl chloride resin, etc. by about 1.01 to 6 times. Among these, a polycarbonate film, a cyclic olefin resin film, a (meth) acrylic resin film or a cellulose resin film is preferably a uniaxially stretched or biaxially stretched film. In the present specification, a zero retardation film is also included in the retardation film (however, it can also be used as a protective film). In addition, a film called a uniaxial retardation film, a wide viewing angle retardation film, a low photoelastic modulus retardation film, or the like is also applicable as the retardation film.

The zero Letters retardation film in-plane retardation value R _e and the thickness direction retardation R _th means a film are both -15～15Nm. This retardation film is suitably used for an IPS mode liquid crystal display device. Plane retardation value R _e and the thickness direction retardation R _th are preferably both -10～10Nm, more preferably both -5～5Nm. Here plane retardation value refers R _e and the thickness direction retardation R _th is a value at a wavelength of 590 nm.

The in-plane retardation value _Re and the thickness direction retardation value R _th are respectively expressed by the following formulas:
_{R e = (n x -n y} ) × d
R _th = [(n _x + _ny ) / 2−n _z ] × d
Defined by Wherein, n _x is a refractive index in a slow axis direction (x-axis direction) in the film plane, n _y is the fast axis direction in the film plane of the (y-axis direction orthogonal to the x-axis in a plane) It is a refractive index, _nz is the refractive index in the film thickness direction (z-axis direction perpendicular to the film surface), and d is the thickness of the film.

  As the zero retardation film, for example, a resin film made of a polyolefin resin such as a cellulose resin, a chain polyolefin resin, and a cyclic polyolefin resin, a polyethylene terephthalate resin, or a (meth) acrylic resin can be used. In particular, a cellulose resin, a polyolefin resin, or a (meth) acrylic resin is preferably used because the retardation value is easily controlled and easily available.

  Moreover, the film which expressed optical anisotropy by application | coating and orientation of a liquid crystalline compound, and the film which expressed optical anisotropy by application | coating of an inorganic layered compound can also be used as retardation film. In such a retardation film, a so-called temperature compensation type retardation film, and a rod-like liquid crystal sold under the trade name “NH film” from JX Nippon Mining & Energy Co., Ltd. are tilted. Film, a film with a disc-shaped liquid crystal sold under the trade name “WV film” from FUJIFILM Corporation, and a complete biaxial film sold under the trade name “VAC film” from Sumitomo Chemical Co., Ltd. Examples of the orientation type film include a biaxial orientation type film sold by Sumitomo Chemical Co., Ltd. under the trade name “new VAC film”. In addition, the resin film laminated | stacked on the at least one surface of retardation film can be the above-mentioned protective film, for example.

[3] Optical layered body FIGS. 4-8 is a schematic sectional drawing which shows the example of the optical laminated body containing the optical film with an adhesive layer formed from the adhesive composition which concerns on this invention.
The optical layered body 5 shown in FIG. 4 has a metal layer 30 (or a metal wiring layer 30) laminated on a substrate 40 and an adhesive film 1a (or a polarizing plate 1a with an adhesive layer). It is the optical laminated body laminated | stacked on the surface at the side of an agent layer. The optical film 1a with an adhesive layer is obtained by laminating an adhesive layer 20 on the surface of the polarizing plate 10a on the polarizer 2 side.

  The optical laminate 6 shown in FIG. 5 is obtained by laminating the metal layer 30 laminated on the substrate 40 on the surface on the pressure-sensitive adhesive layer side of the optical film 1b with pressure-sensitive adhesive layer (or the polarizing plate 1b with pressure-sensitive adhesive layer). It is an optical laminate. The optical film 1b with an adhesive layer is an optical film in which an adhesive layer 20 is laminated on the surface of the polarizing plate 10b on the second resin film 4 side.

  The optical laminated bodies 5 and 6 can be obtained by bonding the optical film with adhesive layer (1a, 1b) to the metal layer 30 laminated on the substrate 40 via the adhesive layer 20.

  Examples of the method for forming the metal layer 30 on the substrate 40 include a sputtering method. The substrate 40 may be a transparent substrate constituting a liquid crystal cell included in the touch input element, and is preferably a glass substrate. As the material of the glass substrate, soda lime glass, low alkali glass, non-alkali glass, or the like can be used. The metal layer 30 may be formed on the entire surface of the substrate 40 or may be formed on a part thereof.

  The metal layer 30 includes, for example, at least one metal element selected from aluminum, copper, silver, iron, tin, zinc, nickel, molybdenum, chromium, tungsten, lead, and an alloy containing two or more of these metals. It may be a layer containing. Among these, from the viewpoint of conductivity, it may be a layer containing at least one metal element selected from aluminum, copper, silver and gold, more preferably from the viewpoint of conductivity and cost. It may be a layer containing an element, more preferably a layer containing an aluminum element as a main component (50% by weight or more of all metal components constituting the metal layer 30).

  The metal layer 30 may be a transparent electrode layer such as ITO (tin-doped indium oxide), and may have a transparent electrode layer made of a metal oxide such as ITO together with the metal layer 30. In addition, you may use the layer which added the metal mesh which arrange | positioned the thin metal wiring layer on the board | substrate, the metal nanoparticle, and the metal nanowire in the binder.

  The method for preparing the metal layer 30 is not particularly limited, and may be a metal foil, which may be formed by a vacuum deposition method, a sputtering method, an ion plating method, an ink jet printing method, or a gravure printing method. The metal layer is preferably formed by a sputtering method, an ink jet printing method, or a gravure printing method, and more preferably a metal layer formed by sputtering. The thickness of the metal layer 30 is not particularly limited, but is usually 3 μm or less, preferably 1 μm or less, more preferably 0.8 μm or less, and usually 0.01 μm or more. Further, when the metal layer 30 is a metal wiring layer (for example, a metal mesh), the line width of the metal wiring is usually 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, and usually 0.5 μm or more. It is.

  The optical laminate 7 shown in FIG. 6 is an optical laminate in which the adhesive layer 20 of the optical film 1 with an adhesive layer is laminated on a substrate 40.

  The optical laminated body 8 shown in FIG. 7 has a resin layer 50 further laminated on the surface of the metal layer 30 laminated on the substrate 40 (on the surface opposite to the substrate 40). It is an optical laminate laminated on the surface of the optical film 1 on the pressure-sensitive adhesive layer 20 side. As resin which forms the resin layer 50, resin etc. which comprise the 1st or 2nd resin film of the said illustration are mentioned, for example.

  In the optical laminate 9 shown in FIG. 8, a plurality of metal layers 30 are laminated on a substrate 40 at predetermined intervals in the vertical and horizontal directions, and between the metal layers 30 (or gaps) and between the metal layers 30. It is the same as the optical laminate 7 except that the resin layer 50 is formed (or laminated) on the surface (on the surface opposite to the substrate 40). When the optical layered body 8 is in a form (a form in which the metal layer 30 is patterned into a predetermined shape), the metal layer 30 is, for example, a metal wiring layer (that is, an electrode layer) of a touch input element included in the touch input type liquid crystal display device. ).

  In the optical layered body 8, the plurality of metal layers 30 may or may not be in contact with the pressure-sensitive adhesive layer 20 in whole or in part. Further, the metal layer 30 may be a continuous film containing the above metal or alloy. The resin layer 50 may be omitted.

  After the optical film (1, 1a, 1b) and the substrate 40 (glass substrate, transparent substrate, etc.) or the metal layer 30 (transparent electrode layer) were bonded to produce an optical laminate, some trouble occurred. In the case where there is, a so-called rework operation is required in which the optical film with the pressure-sensitive adhesive layer is peeled off from the substrate 40 or the metal layer 30 and another optical film 1 with the pressure-sensitive adhesive layer is reattached to the substrate 40 or the metal layer 30. May be. The optical film 1 with the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention hardly causes fogging or adhesive residue on the surface of the glass substrate or the transparent electrode after peeling, and is excellent in reworkability.

[4] Liquid crystal display device The liquid crystal display device according to the present invention includes the optical film 1 with the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to the present invention, and more typically the optical laminated body. Is included. For this reason, the liquid crystal display device according to the present invention has excellent durability.

  The liquid crystal display device according to the present invention may be a touch input type liquid crystal display device having a touch panel function. The touch input type liquid crystal display device includes a touch input element including a liquid crystal cell and a backlight. The configuration of the touch panel may be a known method (for example, an out-cell type, an on-cell type, an in-cell type, etc.), and the operation method of the touch panel may be a known method [for example, a resistive film type, a capacitance type (surface type static type). Capacitance method, projection type capacitance method, etc.). The optical film 1 with an adhesive layer according to the present invention may be disposed on the viewing side of the touch input element (liquid crystal cell), may be disposed on the backlight side, or may be disposed on both. The driving method of the liquid crystal cell may be any conventionally known method such as a TN method, a VA method, an IPS method, a multi-domain method, and an OCB method. In the liquid crystal display device according to the present invention, the substrate 40 included in the optical laminate may be a substrate (typically a glass substrate) included in the liquid crystal cell.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. Hereinafter, the parts and% representing the amount used and the content are based on weight unless otherwise specified.

<Production Example 1: Production of (meth) acrylic resin (A-1) for pressure-sensitive adhesive layer>
In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, a monomer having the composition shown in Table 1 (the numerical values in Table 1 are parts by weight) was mixed with 81.8 parts of ethyl acetate. The resulting solution was charged. After the air in the reaction vessel was replaced with nitrogen gas, the internal temperature was set to 60 ° C. Thereafter, a solution in which 0.12 part of azobisisobutyronitrile was dissolved in 10 parts of ethyl acetate was added. After maintaining at the same temperature for 1 hour, while maintaining the internal temperature at 54 to 56 ° C., ethyl acetate was continuously added into the reaction vessel at an addition rate of 17.3 parts / hr so that the polymer concentration was approximately 35%. Added. After maintaining the internal temperature at 54 to 56 ° C. until 12 hours have passed since the start of the addition of ethyl acetate, ethyl acetate was further added to adjust the polymer concentration to 20%, and a (meth) acrylic resin ( An ethyl acetate solution of A-1) was obtained. The obtained (meth) acrylic resin (A-1) had a weight average molecular weight Mw of 1.39 million and a ratio (Mw / Mn) of the weight average molecular weight Mw to the number average molecular weight Mn of 5.32.

<Production Example 2-12: Production of (meth) acrylic resin (A-2 to 12) for pressure-sensitive adhesive layer>
Except having made the composition of the monomer into the composition shown in Table 1, it carried out similarly to manufacture example 1, and obtained the ethyl acetate solution of (meth) acrylic-type resin (A-2-12) (resin concentration: 20%). The weight average molecular weight Mw of the obtained (meth) acrylic resin (A-2 to 12) was in the range of 1,300,000 to 1,500,000, and Mw / Mn was in the range of 4 to 6.

  In the above production example, the weight average molecular weight Mw and the number average molecular weight Mn are 4 columns of “TSKgel XL” manufactured by Tosoh Corporation and “Shodex GPC KF-” manufactured by Showa Denko KK as a column in the GPC apparatus. 802 "is connected in series, a total of five are connected in series, tetrahydrofuran is used as the eluent, sample concentration is 5mg / mL, sample introduction amount is 100μL, temperature is 40 ° C, flow rate is 1mL / min. It was measured by. The conditions for obtaining the GPC discharge curve were also the same.

  The glass transition temperature Tg was measured using a differential scanning calorimeter (DSC) “EXSTAR DSC6000” manufactured by SII NanoTechnology Co., Ltd., under a nitrogen atmosphere, a measurement temperature range of −80 to 50 ° C., and a heating rate of 10 ° C./min. It measured on condition of this.

  Table 1 shows the composition of the monomer in each production example (the numerical values in Table 1 are parts by weight).

Abbreviations in the column of “monomer composition” in Table 1 mean the following monomers.
BA: butyl acrylate (glass transition temperature of homopolymer: −54 ° C.),
MA: methyl acrylate (glass transition temperature of homopolymer: 10 ° C.),
HEA: 2-hydroxyethyl acrylate.
4HBA: 4-hydroxybutyl acrylate 5HPA: 5-hydroxypentyl acrylate PEA: phenoxyethyl acrylate PEA2: phenoxydiethylene glycol acrylate BMAA: butoxymethylacrylamide AA: acrylic acid

<Examples 1-13, Comparative Examples 1-8>
(1) Preparation of pressure-sensitive adhesive composition The ethyl acetate solution (resin concentration: 20%) of the (meth) acrylic resin obtained in the above production example is shown in Table 2 with respect to 100 parts of the solid content of the solution. A pressure-sensitive adhesive composition obtained by mixing an amount (parts by weight) of a crosslinking agent (B), a silane compound (C), and an ionic compound (D), and further adding ethyl acetate so that the solid content concentration becomes 14%. Got. The compounding amount of each compounding component shown in Table 2 is the number of parts by weight as an active ingredient contained therein when the product used contains a solvent or the like.

The details of each compounding component shown in abbreviations in Table 2 are as follows.
(Crosslinking agent)
B-1: Ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid concentration 75%), trade name “Coronate L” obtained from Tosoh Corporation.
B-2: Trimethylolpropane adduct form of xylylene diisocyanate in ethyl acetate (solid content concentration 75%), trade name “Takenate D-110N” obtained from Mitsui Chemicals, Inc.

(Silane compound)
C-1: 1,6-bis (trimethoxysilyl) hexane, C-2: 1,8-bis (trimethoxysilyl) hexane, C-3: methyl / methoxy group-containing silicone oligomer, Shin-Etsu Chemical Co., Ltd. Trade name “X-40-9250”, C-4: 1,3-bis (3′-trimethoxypropyl) urea obtained from

(Ionic compounds)
D-1: N-decylpyridinium bis (fluorosulfonyl) imide, D-2: Potassium bis (fluorosulfonyl) imide, D-3: Lithium bis (trifluoromethylsulfonyl) imide, D-4: N-decyl Pyridinium tetra (pentafluorophenyl) borate.

(2) Production of pressure-sensitive adhesive layer Each pressure-sensitive adhesive composition prepared in the above (1) was separated from a polyethylene terephthalate film subjected to a release treatment [trade name “PLR-382051 obtained from Lintec Corporation]. ]] Was applied using an applicator so that the thickness after drying was 20 μm, and dried at 100 ° C. for 1 minute to prepare an adhesive layer (adhesive sheet).

(3) Production of optical film with pressure-sensitive adhesive layer (P-1) Polyvinyl alcohol film having an average degree of polymerization of about 2400, a saponification degree of 99.9 mol%, and a thickness of 60 μm [trade name “Kuraray Vinylon VF manufactured by Kuraray Co., Ltd.” -PE # 6000 "] is immersed in pure water at 37 ° C, and then an aqueous solution containing iodine and potassium iodide (iodine / potassium iodide / water (weight ratio) = 0.04 / 1.5 / 100). Soaked at 30 ° C. Then, it was immersed at 56.5 ° C. in an aqueous solution containing potassium iodide and boric acid (potassium iodide / boric acid / water (weight ratio) = 12 / 3.6 / 100). The film was washed with pure water at 10 ° C. and then dried at 85 ° C. to obtain a polarizer having a thickness of about 23 μm in which iodine was adsorbed and oriented on polyvinyl alcohol. Stretching was mainly performed in the iodine staining and boric acid treatment steps, and the total stretching ratio was 5.3 times.

A transparent protective film [trade name “KC2UA” manufactured by Konica Minolta Opto Co., Ltd.] made of a 25 μm-thick triacetyl cellulose film is placed on one side of the obtained polarizer with an adhesive made of an aqueous solution of a polyvinyl alcohol resin. And pasted. Next, a zero retardation film [trade name “ZEONOR” manufactured by Nippon Zeon Co., Ltd.] made of a cyclic polyolefin resin having a thickness of 23 μm is formed on the surface opposite to the triacetyl cellulose film in the polarizer. A bonded polarizing plate was produced through an adhesive made of an aqueous resin solution. Next, after the corona discharge treatment for improving adhesion is performed on the surface of the zero retardation film opposite to the surface in contact with the polarizer, it is opposite to the separate film of the pressure-sensitive adhesive layer prepared in (2) above. After laminating the side surface (the pressure-sensitive adhesive layer surface) with a laminator, the film was cured for 7 days under the conditions of a temperature of 23 ° C. and a relative humidity of 65% to obtain an optical film with a pressure-sensitive adhesive layer (P-1).

(4) Durability evaluation of optical film with pressure-sensitive adhesive layer The optical film with pressure-sensitive adhesive layer (P-1) produced in (3) above is 300 mm × 220 mm so that the stretching axis direction of the polarizing plate is the long side. It cut | judged to a magnitude | size, the separate film was peeled, and the exposed adhesive layer surface was bonded to the glass substrate or the glass base | substrate with ITO (tin dope indium oxide). The test piece (the optical film with the pressure-sensitive adhesive layer to which the glass substrate was attached) obtained by attaching the obtained glass substrate was placed in an autoclave at a temperature of 50 ° C. and a pressure of 5 kg / cm ² (490.3 kPa) for 20 minutes. Pressurized. A non-alkali glass product name “Eagle XG” manufactured by Corning was used for the glass substrate. In addition, as a glass substrate with ITO, a non-alkali glass manufactured by Corning [trade name “Eagle XG”] having a 30 nm ITO layer formed by ITO deposition was used.
About the obtained optical laminated body, the following 3 types of durability tests were implemented.

[Durability test]
・ Heat resistance test held at a temperature of 95 ℃ for 1000 hours (glass substrate)
・ Heat resistance test held at a temperature of 95 ℃ for 1000 hours (Glass with ITO)
-Moisture and heat resistance test (glass substrate) held for 1000 hours in an environment of temperature 60 ° C and relative humidity 90%,
・ Heat shock (HS) test (glass substrate) that is held for 30 minutes under a drying condition at a temperature of 85 ° C. and then held for 30 minutes under a drying condition at a temperature of −40 ° C. for one cycle. .

  The optical layered body after each test was visually observed, and the presence or absence of appearance changes such as lifting, peeling and foaming of the pressure-sensitive adhesive layer was visually observed, and durability was evaluated according to the following evaluation criteria. The results are shown in Table 3.

5: No change in appearance such as floating, peeling, foaming, etc.
4: Almost no change in appearance such as floating, peeling, foaming, etc.
3: Appearance changes such as floating, peeling and foaming are slightly noticeable.
2: Appearance changes such as floating, peeling, foaming are conspicuous,
1: Appearance changes such as floating, peeling, foaming, etc. are noticeable.

(5) Evaluation of adhesive strength of optical film with pressure-sensitive adhesive layer The optical film with pressure-sensitive adhesive layer (P-1) prepared in the above (3) was cut into a test piece having a size of 25 mm x 150 mm. The separator was peeled off from the test piece, and the pressure-sensitive adhesive surface was attached to a glass substrate. The test piece (the optical film with the pressure-sensitive adhesive layer to which the glass substrate was attached) obtained by attaching the obtained glass substrate was placed in an autoclave at a temperature of 50 ° C. and a pressure of 5 kg / cm ² (490.3 kPa) for 20 minutes. Pressurized. After storing for 24 hours in an atmosphere having a temperature of 23 ° C. and a relative humidity of 50%, the optical film was peeled from the test piece together with the pressure-sensitive adhesive layer in the direction of 180 ° at a speed of 300 mm / min. Table 3 shows the average peeling force at the time of peeling as the adhesive strength. When the adhesive force is 10 N or less, the rework property is excellent, and when it is 0.5 N or more, peeling hardly occurs even when an impact is applied from the end of the polarizing plate.

[Evaluation of ITO corrosivity of optical laminates]
The surface resistance (surface resistance value before the test) of the ITO layer of the glass substrate with the ITO layer was measured with a low resistivity meter (trade name “Loresta-AX” manufactured by Mitsubishi Chemical Analytech Co., Ltd.). Next, the polarizing plate on which the pressure-sensitive adhesive layer prepared in the above (3) is formed is cut into a test piece having a size of 20 mm × 40 mm, and attached to the ITO layer side of the glass substrate via the pressure-sensitive adhesive layer. did. The obtained optical layered body was stored in an oven at a temperature of 60 ° C. and a relative humidity of 90% for 500 hours, and then peeled between the ITO layer and the adhesive layer in an atmosphere at a temperature of 23 ° C. and a relative humidity of 50%. did. The surface resistance (surface resistance value after test) of the ITO layer after peeling was measured. The rate of change in resistance before and after the test was calculated by the following formula and evaluated according to the following criteria. The smaller the rate of resistance change, the lower the ITO corrosivity. The results are shown in Table 3.
Resistance change rate (%) = [(surface resistance value after test) − (surface resistance value before test)] / [surface resistance value before test] × 100

<Evaluation criteria for ITO corrosivity>
◯: An optical laminate having a resistance change rate of less than 50% and good ITO corrosivity.
X: The resistance change rate is 50% or more, and the ITO corrosiveness of the optical laminate is poor.

(6) Evaluation of antistatic property of optical film with adhesive layer
After removing the separator of the obtained polarizing film with the pressure-sensitive adhesive layer, the surface resistance value of the pressure-sensitive adhesive is measured with a surface resistivity measuring device ["HIRESTA-up MCP-HT450" (trade name) manufactured by Mitsubishi Chemical Corporation]. It was measured by. The measurement was performed under the measurement conditions of an applied voltage of 250 V and an applied time of 10 seconds. If the surface resistance value is 1.0 × 10 ¹² Ω / □ or less, good antistatic properties can be obtained.

[Gel fraction of adhesive sheet]
The gel fraction evaluation method of the adhesive sheet of this invention is shown. The larger the gel fraction, the more cross-linking reactions are progressing in the pressure-sensitive adhesive, and this can be used as a measure of the cross-linking density. The gel fraction is a value measured according to the following (1) to (4).

(1) An adhesive sheet having an area of about 8 cm × about 8 cm and a metal mesh made of SUS304 (about 10 cm × about 10 cm) (with a weight of Wm) are bonded.
(2) Weigh the bonded product obtained in (1) above, weigh it Ws, then fold it 4 times so as to wrap the adhesive sheet, weigh it with a stapler (stapler), weigh it, Let the weight be Wb.
(3) The mesh stapled in (2) above is placed in a glass container, and 60 mL of ethyl acetate is added and immersed, and then the glass container is stored at room temperature for 3 days.
(4) The mesh is taken out from the glass container, dried at 120 ° C. for 24 hours, weighed, the weight is taken as Wa, and the gel fraction is calculated based on the following formula.
Gel fraction (% by weight) = [{Wa− (Wb−Ws) −Wm} / (Ws−Wm)] × 100

  DESCRIPTION OF SYMBOLS 1,1a, 1b ... Optical film with an adhesive layer, 2 ... Polarizer, 3 ... 1st resin film, 4 ... 2nd resin film, 5, 6, 7, 8, 9 ... Optical laminated body, 10 ... Optical film DESCRIPTION OF SYMBOLS 10a, 10b ... Polarizing plate, 20 ... Adhesive layer, 30 ... Metal layer, 40 ... Substrate, 50 ... Resin layer.

Claims (13)

A pressure-sensitive adhesive composition comprising a (meth) acrylic resin (A), a crosslinking agent (B), and a silane compound (C),
The (meth) acrylic resin (A) is represented by the following formula (a1)

(In the formula, n represents an integer of 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, X ¹ represents a methylene group which may have a substituent, and when n is 2 or more, The substituents may be the same or different)
A pressure-sensitive adhesive composition comprising a structural unit derived from a hydroxy group-containing (meth) acrylate and a structural unit derived from 5-hydroxypentyl acrylate.   The proportion of the structural unit derived from the hydroxy group-containing (meth) acrylate represented by the formula (a1) with respect to 100 parts by weight of all the structural units constituting the (meth) acrylic resin is 1.5 to 4.5 parts by weight. The pressure-sensitive adhesive composition according to claim 1, wherein the proportion of the structural unit derived from 5-hydroxypentyl acrylate is 0.25 to 1.0 part by weight.   The (meth) acrylic resin is composed of a structural unit derived from an alkyl acrylate (a3-1) having a glass transition temperature of the homopolymer of less than 0 ° C. and a structural unit derived from an alkyl acrylate having a glass transition temperature of the homopolymer of 0 ° C. or higher ( The pressure-sensitive adhesive composition according to claim 1 or 2, comprising a structural unit derived from an alkyl acrylate (a3) containing a3-2).   Ratio of structural unit derived from alkyl acrylate (a3-1) having a glass transition temperature of less than 0 ° C. of homopolymer and structural unit derived from alkyl acrylate (a3-2) having a glass transition temperature of homopolymer of 0 ° C. or higher ( The pressure-sensitive adhesive composition according to claim 3, wherein (weight ratio) is (a3-1) / (a3-2) = 20/80 to 95/5. The pressure-sensitive adhesive composition according to claim 1, wherein the weight average molecular weight of the (meth) acrylic resin is 6.0 × 10 ^{5 to} 2.5 × 10 ⁶ in terms of polystyrene.   The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the crosslinking agent (B) is an adduct of an aromatic isocyanate compound and / or a polyhydric alcohol compound of the aromatic isocyanate compound.   The ratio of a crosslinking agent (B) is 0.01-10 weight part with respect to 100 weight part of (meth) acrylic-type resin (A), The adhesive composition in any one of Claims 1-6. The silane compound (C) is represented by the following formula (c1)

(In formula, B shows a C1-C20 alkanediyl group or a C3-C20 bivalent alicyclic hydrocarbon group, and comprises the said alkanediyl group and the said alicyclic hydrocarbon group. —CH ₂ — may be substituted with —O— or —CO—, R ¹ represents an alkyl group having 1 to 5 carbon atoms, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each Independently, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is shown)
The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition is represented by the formula: B in the formula (c1) is an alkanediyl group having 1 to 10 carbon atoms, R ¹ is an alkyl group having 1 to 5 carbon atoms, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independent. The pressure-sensitive adhesive composition according to claim 8, which is an alkoxy group having 1 to 5 carbon atoms.   The ratio of a silane compound (C) is 0.01-10 weight part with respect to 100 weight part of (meth) acrylic-type resin (A), The adhesive composition in any one of Claims 1-9.   The pressure-sensitive adhesive composition according to any one of claims 1 to 10, wherein a gel fraction of the pressure-sensitive adhesive formed from the pressure-sensitive adhesive composition is 50 to 95%.   A pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition is bonded to a glass substrate, and the pressure-sensitive adhesive strength of the pressure-sensitive adhesive layer after 24 hours under conditions of a temperature of 23 ° C. and a relative humidity of 50% is a peeling rate of 300 mm / min. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition is 0.5 to 10 N / 25 mm.   The pressure-sensitive adhesive composition according to claim 1, which is used for forming a pressure-sensitive adhesive layer laminated on an optical film.

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