TWI728014B - Adhesive composition - Google Patents

Abstract

The present invention provides an adhesive composition capable of forming a adhesive layer exhibiting excellent durability even under severe durability conditions.

The adhesive composition comprises a (meth)acrylic resin (A), a crosslinking agent (B) and a silane compound (C), wherein the (meth) acrylic resin (A) comprises a structural unit derived from a hydroxy group-containing (meth) acrylate represented by the following formula (a1) and the following formula (a2), and the crosslinking agent (B) is an adduct of a tolylene diisocyanate compound and/or a tolylene diisocyanate compound with a polyhydric alcohol compound:

Description

Adhesive composition

The present invention relates to an adhesive composition that is useful for forming an adhesive layer with excellent durability in optical films, etc., which are applied to an adhesive layer of a liquid crystal display device.

An optical film represented by a polarizer formed 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. Optical films such as polarizing plates are mostly used by bonding them to other members (for example, liquid crystal cells in liquid crystal display devices) through an adhesive layer (see Patent Document 1). Therefore, as an optical film, an optical film having an adhesive layer preliminarily provided with an adhesive layer on one side is known.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] JP 2010-229321 A

In recent years, liquid crystal display devices have been used in smart phones and The use of tablet-type terminal equipment as a representative mobile device and the use of in-vehicle devices such as a car navigation system continue to develop. Compared with the conventional indoor TV use, there is a possibility of being exposed to a harsher environment in this use, so improving the durability of the device becomes a problem.

Durability is similarly required in optical films with adhesive layers constituting liquid crystal display devices and the like. That is, the adhesive layer assembled in the liquid crystal display device, etc., may be placed in a high temperature or high temperature and high humidity environment, or in an environment where high temperature and low temperature alternate alternately. Optical films with adhesive layers are required Even in these environments, it is possible to suppress defects such as floating, peeling, and foaming of the adhesive layer at the interface between the adhesive layer and the optical member to which it is bonded, and it is also required that the optical properties are not degraded . Especially when the optical film is a polarizing plate, the adhesive layer is required to have higher durability than ordinary optical films because of stronger shrinkage stress in a high-temperature environment. Due to the increasing demand for improving the durability of the above-mentioned liquid crystal display device, the durability required for the adhesive layer has become very strict at present.

Therefore, the object of the present invention is to provide an adhesive composition that can form an adhesive layer exhibiting excellent durability even under such severe durability conditions.

In order to solve the above-mentioned problems, the present inventors have completed the present invention as a result of intensive research.

That is, the present invention includes the following contents.

(式中，n係表示1至4的整數，A¹係表示氫原子或烷基，X¹係表示可具有取代基之亞甲基，n為2以上時，前述取代基可相同或不同)及源自下述式(a2)表示之含羥基的(甲基)丙烯酸酯之結構單元，

(式中，m係表示5以上的整數，A²係表示氫原子或烷基，X²係表示亦可具有取代基之亞甲基，前述取代基可相同或不同) 前述交聯劑(B)係甲苯二異氰酸酯系化合物及/或甲苯二異氰酸酯系化合物加添多元醇化合物所得到的加成物。 [1] An adhesive composition containing a (meth)acrylic resin (A), a crosslinking agent (B), and a silane compound (C), wherein the (meth)acrylic resin (A) is Contains: a structural unit derived from a hydroxyl-containing (meth)acrylate represented by the following formula (a1),

(In the formula, n represents an integer from 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, and X ¹ represents a substituted methylene group. When n is 2 or more, the aforementioned substituents may be the same or different) And a structural unit derived from the hydroxyl-containing (meth)acrylate represented by the following formula (a2),

(In the formula, m represents an integer of 5 or more, A ² represents a hydrogen atom or an alkyl group, and X ² represents a methylene group that may have a substituent. The substituents may be the same or different.) The crosslinking agent (B ) A toluene diisocyanate compound and/or an adduct obtained by adding a polyol compound to a toluene diisocyanate compound.

[2] The adhesive composition according to [1], wherein it is derived from the hydroxyl-containing (methyl) represented by the formula (a1) with respect to 100 parts by weight of the total structural units constituting the (meth)acrylic resin The ratio of the structural units of the acrylate is 1.5 to 4.5 parts by weight, and the ratio of the structural units derived from the hydroxyl-containing (meth)acrylate represented by the formula (a2) is 0.25 to 1.0 parts by weight.

[3] The adhesive composition according to [1] or [2], wherein the (meth)acrylic resin contains a structural unit derived from alkyl acrylate (a3), which is derived from acrylic The structural unit of alkyl enoate (a3) includes: structural unit of alkyl acrylate (a3-1) derived from homopolymer whose glass transition temperature is less than 0°C; and glass derived from homopolymer The structural unit of alkyl acrylate (a3-2) whose transition temperature is above 0°C.

[4] The adhesive composition according to [3], wherein the structural unit of alkyl acrylate (a3-1) derived from the homopolymer having a glass transition temperature of less than 0°C is the same as the structural unit derived from the homopolymer The ratio (weight ratio) between the structural units of alkyl acrylate (a3-2) whose glass transition temperature is above 0℃ is (a3-1)/(a3-2)=20/80 to 95/ 5.

[5] The 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× in terms of polystyrene 10 ⁶ .

[6] The adhesive composition according to any one of [1] to [5], wherein the ratio of the crosslinking agent (B) to 100 parts by weight of the (meth)acrylic resin (A) It is 0.01 to 10 parts by weight.

(式中，B係表示碳數1至20的烷二基或碳數3至20的二價脂環式烴基，構成前述烷二基及前述脂環式烴基之-CH₂-亦可置換成-O-或-CO-，R¹係表示碳數1至5的烷基，R²、R³、R⁴、R⁵及R⁶係各自獨立地表示碳數1至5的烷基或碳 數1至5的烷氧基)。 [7] The adhesive composition according to any one of [1] to [6], wherein the silane compound (C) is a silane compound represented by the following formula (c1),

(In the formula, B represents an alkanediyl group having 1 to 20 carbons or a divalent alicyclic hydrocarbon group having 3 to 20 carbons, and -CH ₂ -constituting the aforementioned alkanediyl group and the aforementioned alicyclic hydrocarbon group can also be substituted with -O- or -CO-, R ¹ represents an alkyl group having 1 to 5 carbons, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 5 carbons or carbon Alkoxy group from 1 to 5).

[8] The adhesive composition according to [7], wherein B in the formula (c1) is an alkanediyl group having 1 to 10 carbons, R ¹ is an alkyl group having 1 to 5 carbons, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkoxy group having 1 to 5 carbon atoms.

[9] The adhesive composition according to any one of [1] to [8], wherein the ratio of the silane compound (C) to 100 parts by weight of the (meth)acrylic resin (A) is 0.01 to 10 parts by weight.

[10] The adhesive composition according to any one of [1] to [9], wherein the gel fraction of the adhesive formed from the adhesive composition is 50 to 95%.

[11] The adhesive composition according to any one of [1] to [10], wherein the adhesive layer formed of the aforementioned adhesive composition is bonded to a glass substrate at a temperature of 23° C. The adhesive force of the aforementioned adhesive layer after 24 hours at a humidity of 50% is 0.5 to 10N/25mm at a peeling speed of 300mm/min.

[12] The adhesive composition described in any one of [1] to [11] is used to form an adhesive layer laminated on an optical film.

The adhesive composition of the present invention can form an adhesive layer with excellent durability even under severe durability conditions.

1, 1a, 1b‧‧‧Optical film with adhesive layer

2‧‧‧Polarizer

3‧‧‧The first resin film

4‧‧‧Second resin film

5, 6, 7, 8, 9‧‧‧Optical laminate

10‧‧‧Optical Film

10a、10b‧‧‧Polarizer

20‧‧‧Adhesive layer

30‧‧‧Metal layer

40‧‧‧Substrate

50‧‧‧Resin layer

Fig. 1 is a schematic cross-sectional view showing an example of an optical film with an adhesive layer formed of the adhesive composition of the present 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 structure 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 of the adhesive composition of the present invention.

Fig. 5 is a schematic cross-sectional view showing an example of an optical laminate including an optical film with an adhesive layer formed of the adhesive composition of the present invention.

Fig. 6 is a schematic cross-sectional view showing another example of an optical laminate including an optical film with an adhesive layer formed of the adhesive composition of the present invention.

FIG. 7 is a schematic cross-sectional view showing another example of an optical laminate including an optical film with an adhesive layer formed from the adhesive composition of the present invention.

FIG. 8 is a schematic cross-sectional view showing another example of an optical laminate including an optical film with an adhesive layer formed from the adhesive composition of the present invention.

[1] Adhesive composition

The adhesive composition of the present invention contains a (meth)acrylic resin (A), a crosslinking agent (B), and a silane compound (C).

[1-1] (Meth) acrylic resin (A)

The (meth)acrylic resin (A) is a poly(meth)acrylic monomer-derived structural unit as the main component (preferably containing 50% by weight or more) A compound or copolymer comprising a structural unit derived from a hydroxyl-containing (meth)acrylate represented by the following formulas (a1) and (a2).

(式中，n係表示1至4的整數，A¹係表示氫原子或烷基，X¹係表示可具有取代基之亞甲基，n為2以上時，前述取代基可相同或不同)

(In the formula, n represents an integer from 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, and X ¹ represents a substituted methylene group. When n is 2 or more, the aforementioned substituents may be the same or different)

(式中，m係表示5以上的整數，A²係表示氫原子或烷基，X²係表示可具有取代基之亞甲基，前述取代基可相同或不同)

(In the formula, m is an integer of 5 or more, A ² is a hydrogen atom or an alkyl group, and X ² is a methylene group that may have a substituent. The aforementioned substituents may be the same or different)

That is, because the (meth)acrylic resin (A) of the present invention has hydroxyalkyl groups with different carbon chain lengths (n and m) in the side chain, it is estimated that the adhesive layer formed by the adhesive composition, The system can optimize the crosslink density between (meth)acrylic resins. By optimizing the cross-linking density, an adhesive layer with an excellent balance of hardness and softness (or having the best hardness) can be formed, so durability can be improved and interfacial peeling can be effectively suppressed even in a high-temperature environment (Or float) and foam. Moreover, even if a strong shrinkage stress is generated, the adhesive layer can effectively alleviate the stress, so it is possible to prevent white spots caused by the shrinkage of the optical film (for example, deflection plate). Furthermore, by optimizing the crosslink density, reworkability (peelability) can also be improved. In addition, in this specification, the so-called durability refers to, for example, an environment in which high temperature and low temperature alternate in a high-temperature environment, high-temperature and high-humidity environment. Inferior, it can suppress floating and peeling at the interface between the adhesive layer and the adjacent optical member (also called peeling resistance), and can suppress defects such as foaming in the adhesive layer Characteristics (also called foam resistance). In addition, in the present invention, the so-called anti-aggregation destruction property refers to the characteristic that can suppress the aggregation destruction (or breakage) of the adhesive layer.

In formula (a1) and formula (a2), X ¹ and X ² represent an optionally substituted methylene group. Examples of the substituent include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), alkyl groups (for example, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, _{C 1-10} alkyl such as tertiary butyl, pentyl, hexyl, etc., preferably C _1-6 alkyl, more preferably C _1-3 alkyl), cycloalkyl (cyclopentyl, cyclohexyl, etc.) ), aryl [phenyl, alkyl phenyl (tolyl, xylyl, etc.)] aralkyl (benzyl, etc.), alkoxy (such as methoxy, ethoxy, etc. C _1-4 alkane Oxy), polyoxyalkylene (e.g., dioxyethylene, etc.), cycloalkoxy (e.g., C _5-10 cycloalkoxy such as cyclohexyloxy, etc.), aryloxy (e.g., phenoxy Etc.), aralkyloxy (e.g., benzyloxy, etc.), alkylthio (e.g., methylthio, ethylthio, etc. C _1-4 alkylthio, etc.), cycloalkylthio (e.g., cyclohexylthio Group, etc.), arylthio group (e.g. thiophenoxy group, etc.), aralkylthio group (e.g. benzylthio group, etc.), acyl group (e.g. acetyl group, etc.), nitro group, cyano group, and the like. Among them, halogen atoms, alkyl groups, alkoxy groups, aryloxy groups, etc. are preferred, and alkyl groups (e.g., methyl, ethyl, etc.) are particularly preferred.

A ¹ and A ² each represent a hydrogen atom or an alkyl group, and the alkyl group may be ^{the alkyl group exemplified in X 1} and X ² (preferably a methyl group or the like).

In formula (a1), n represents an integer of 1 to 4, preferably an integer of 1 to 3, more preferably 2. Also, in formula (a2), m is an integer of 5 or more (example Such as an integer from 5 to 20), preferably from 5 to 15 (for example, an integer from 5 to 11), more preferably from 5 to 9 (for example, an integer from 5 to 7), especially 5. In addition, m may be an even number of 5 or more (for example, 6, 8, 10, 12, etc.), or an odd number of 5 or more (for example, 5, 7, 9, 11, etc.).

Specific examples of the hydroxyl-containing (meth)acrylate (a1) include 1-hydroxymethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, and 1-hydroxy (meth)acrylate _{1-hydroxy C 1-8} alkyl (meth)acrylate such as heptyl ester, 1-hydroxybutyl (meth)acrylate, 1-hydroxypentyl (meth)acrylate, etc.; 2-hydroxyethyl (meth)acrylate (Meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxypentyl (meth)acrylate, 2-hydroxyhexyl (meth)acrylate, etc. ) 2-hydroxy C _2-9 alkyl acrylate; 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 3-hydroxypentyl (meth)acrylate, (meth)acrylic acid _{3-hydroxy C 3-10} alkyl (meth)acrylate such as 3-hydroxyhexyl ester, 3-hydroxyheptyl (meth)acrylate, etc.; 4-hydroxybutyl (meth)acrylate, (meth)acrylic acid 4 -Hydroxypentyl, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyheptyl (meth)acrylate, 4-hydroxyoctyl (meth)acrylate and other (meth)acrylic acid 4-hydroxy C _{4- 11} Alkyl esters; 2-chloro-2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate Wait. Among these, from the standpoint of durability, 2-hydroxyethyl acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, etc., are hydroxy-containing compounds where n is 2 (Meth) acrylate; 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 3-hydroxypentyl (meth)acrylate, etc. n is 3 hydroxyl-containing (methyl) ) Acrylate is preferred. The hydroxyl-containing (meth)acrylate with n being 2 is particularly preferred, and among these, 2-hydroxyethyl (meth)acrylate is preferred.

Specific examples of the hydroxyl-containing (meth)acrylate (a2) include 5-hydroxypentyl (meth)acrylate, 5-hydroxyhexyl (meth)acrylate, 5-hydroxyl (meth)acrylate _{5-hydroxy C 5-12} alkyl (meth)acrylate such as heptyl ester, 5-hydroxyoctyl (meth)acrylate, 5-hydroxynonyl (meth)acrylate, etc.; 6-hydroxyhexyl (meth)acrylate (Meth)acrylate, 6-hydroxyheptyl (meth)acrylate, 6-hydroxyoctyl (meth)acrylate, 6-hydroxynonyl (meth)acrylate, 6-hydroxydecyl (meth)acrylate, etc. ) 6-hydroxy C _6-13 alkyl acrylate; 7-hydroxyheptyl (meth)acrylate, 7-hydroxyoctyl (meth)acrylate, 7-hydroxynonyl (meth)acrylate, (meth)acrylic acid _{7-hydroxyl C 7-14} alkyl (meth)acrylate such as 7-hydroxydecyl, 7-hydroxyundecyl (meth)acrylate, etc.; 8-hydroxyoctyl (meth)acrylate, (meth)acrylic acid 8-hydroxynonyl (meth)acrylate, 8-hydroxydecyl (meth)acrylate, 8-hydroxyundecyl (meth)acrylate, 8-hydroxydodecyl (meth)acrylate, etc. C _8-15 alkyl ester; 9-hydroxynonyl (meth)acrylate, 9-hydroxydecyl (meth)acrylate, 9-hydroxyundecyl (meth)acrylate, 9-hydroxydecyl (meth)acrylate Diester, 9-hydroxytridecyl (meth)acrylate, 9-hydroxy C _9-16 (meth)acrylate, etc.; 10-hydroxydecyl (meth)acrylate, 10-(meth)acrylate _{(Meth)acrylic acid 10-hydroxy C 10-17} such as hydroxyundecyl ester, 10-hydroxyldecyl (meth)acrylate, 10-hydroxytridecyl acrylate, 10-hydroxytetradecyl (meth)acrylate, etc. Alkyl ester; 11-hydroxyundecyl (meth)acrylate, 11-hydroxydodecyl (meth)acrylate, 11-hydroxytridecyl (meth)acrylate, 11-hydroxytetradecyl (meth)acrylate , (Meth)acrylic acid 11-hydroxypentadecyl ester, etc. (meth)acrylic acid 10-hydroxy C _11-18 alkyl ester; (meth)acrylic acid 12-hydroxyl dodecyl ester, (meth)acrylic acid 12-hydroxydecyl ester Triester, 12-hydroxytetradecyl (meth)acrylate, etc., 12-hydroxy C _12-19 alkyl (meth)acrylate; 13-hydroxypentadecyl (meth)acrylate, 13-(meth)acrylate _{13-hydroxy C 13-20} alkyl (meth)acrylate such as hydroxytetradecyl ester, 13-hydroxypentadecyl (meth)acrylate, etc.; 14-hydroxytetradecyl (meth)acrylate, (meth)acrylic acid 14-hydroxypentadecyl ester and other (meth) hydroxy C _14-21 alkyl acrylate; 15-hydroxy pentadecyl (meth) acrylate, 15-hydroxy heptadecyl (meth) acrylate, etc. (A Base) 15-hydroxy C _15-22 alkyl acrylate and the like. Among them, from the standpoint of durability, 5-hydroxypentyl (meth)acrylate, 5-hydroxyhexyl (meth)acrylate, 5-hydroxyheptyl (meth)acrylate, (meth) ) 5-hydroxyoctyl acrylate, 5-hydroxynonyl (meth)acrylate, and the like, hydroxy-containing (meth)acrylates where n is 5 are preferred, and 5-hydroxypentyl (meth)acrylate is particularly preferred.

The ratio of the structural units derived from the hydroxyl-containing (meth)acrylate represented by formula (a1) to 100 parts by weight of the total structural units constituting the (meth)acrylic resin is preferably 1.5 to 4.5 parts by weight , The ratio of the structural units derived from the hydroxyl-containing (meth)acrylate represented by the formula (a2) is preferably 0.25 to 1.0 parts by weight. In addition, the ratio (weight) between the structural unit derived from the hydroxyl-containing (meth)acrylate represented by the formula (a1) and the structural unit derived from the hydroxyl-containing (meth)acrylate represented by the formula (a2) The ratio) system is not particularly limited as long as it is within the above range, and is preferably (a1)/(a2)=13/1 to 3/1 (for example, 11/1 to 3/1), and more preferably 9/ 1 to 4/1, especially 7/1 to 5/1. Within the above range, it is advantageous to form an optimal cross-linked structure and can improve characteristics such as durability.

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

Among the alkyl acrylates (a3), for the alkyl acrylates (a3-1) whose glass transition temperature (Tg) of the homopolymer is less than 0°C, for example, ethyl acrylate, normal acrylate and isopropyl acrylate can be mentioned. Propyl ester, n- and isobutyl acrylate, n-pentyl acrylate, n- and isohexyl acrylate, n-heptyl acrylate, n- and isooctyl acrylate, 2-ethylhexyl acrylate, n- and isononyl acrylate, n-acrylate And isodecyl ester, n-lauryl acrylate and other straight-chain or branched-chain alkyl acrylates with the carbon number of the alkyl group from 2 to 12 or so. The alkyl acrylate (a3) may also be an alkyl acrylate (cycloalkyl acrylate) having an alicyclic structure. From the viewpoint of compliance (or flexibility and adhesion) to optical films, it is based on carbon The alkyl acrylate having a number of 2 to 10 is preferably an alkyl acrylate having a carbon number of 3 to 8, more preferably an alkyl acrylate having a carbon number of 4 to 6, and particularly preferably n-butyl alkyl acrylate. When n-butyl alkyl acrylate is used, it is possible to improve the followability, and for example, it is advantageous for the peeling resistance and the like. These alkyl acrylates (a3-1) can be used alone or in combination of two or more kinds.

As for the alkyl acrylate (a3-2) whose Tg of the homopolymer is 0°C or higher, methyl acrylate, cycloalkyl acrylate (for example, cyclohexyl acrylate, isobornyl acrylate), and stearyl acrylate can be mentioned. Ester, tert-butyl acrylate, etc., especially methyl acrylate is particularly preferred. When methyl acrylate is used, the strength can be improved, which is advantageous for cohesion failure, for example. These alkyl acrylates (a3-2) can be used alone or in combination of two or more kinds. Also, for the Tg of the homopolymer of alkyl acrylate, for example, refer to POLYMER HANDBOOK (Wiley-Interscience) and other literature values.

The ratio of the structural unit derived from alkyl acrylate in the (meth)acrylic resin (A) is relative to the structure of the (meth)acrylic from the viewpoint of durability and reworkability of the adhesive layer 100 parts by weight of the total structural unit of the resin (A) is, 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), more preferably 70 parts by weight or more ( For example, 80 to 90 parts by weight).

If the homopolymer has an alkyl acrylate whose Tg is less than 0°C, and the homopolymer has an alkyl acrylate whose Tg is 0°C or higher, it can have both cohesion resistance and compliance resistance (foaming resistance). Resistance and peeling resistance) and can improve the durability against dimensional changes of optical films (such as polarizing plates).

The structural unit derived from alkyl acrylate (a3-1) whose glass transition temperature is less than 0℃ and the structural unit derived from alkyl acrylate (a3-2) whose glass transition temperature is above 0℃ The ratio (weight ratio) between (a3-1)/(a3-2)=20/80 to 95/5 (for example, 30/70 to 90/10), preferably 40/60 to 85/15, More preferably, it is 55/45 to 75/25. Within the above range, durability can be further improved. The greater the ratio of structural units derived from the alkyl acrylate (a3-1) whose glass transition temperature is less than 0°C, the more the followability is improved. The greater the ratio of structural units derived from alkyl acrylate (a3-2) whose glass transition temperature is 0°C or higher, the greater the resistance to agglomeration destruction.

As the substituent-containing alkyl acrylate (a4), for example, an alkyl acrylate in which a substituent (a hydrogen atom of the alkyl group is substituted by a substituent) is introduced into the alkyl group of the aforementioned alkyl acrylate (a3-1). The substituent system may be, for example, an aryl group (such as a phenyl group), an aryloxy group (a phenoxy group), an alkoxy group (such as a methoxy group, an ethoxy group, etc.) and the like. As the substituent-containing alkyl acrylate (a3-3), for example, alkoxyalkyl acrylate (for example, 2-methoxyethyl acrylate, ethoxymethyl acrylate, etc.), aryloxyalkyl acrylate (For example, phenoxyethyl acrylate, etc.), aryloxy polyalkylene glycol monoacrylate, polyalkylene glycol monoacrylate, and the like. These alkyl acrylates (a3-3) can be used individually or in combination of 2 or more types. By containing the alkyl acrylate containing an aromatic ring containing an aryl group, an aryloxy group, etc., the white spots produced by the polarizing plate can be improved during the durability test. In addition, the alkylene groups of aryloxy polyalkylene glycol monoacrylate and polyalkylene glycol monoacrylate may be, for example, C _1-6 alkylene groups such as methylene, ethylene, and propylene (more Preferably, ethylene group, etc.), etc., from the viewpoint of durability of the adhesive layer formed by the adhesive composition, the repeating unit system of the oxyalkylene group may be, for example, 2 to 7, preferably 2 to 5 ( Especially 2). In the present invention, since the (meth)acrylic resin (A) and the crosslinking agent (B) described later are contained in the adhesive composition, the optimal crosslinking structure (or crosslinking density) can be formed, so even if oxygen stretches The alkyl group has a small number of repeating units and can also show good reworkability. Specifically, for example, phenoxy two to seven C _1-3 alkanediol-acrylates such as phenoxy diethylene glycol acrylate, and diethylene glycol monoacrylate such as di to seven C _{1- 3} alkanediol-monoacrylate and so on.

The ratio of the structural unit derived from the substituent-containing alkyl acrylate relative to 100 parts by weight of the total structural unit constituting the (meth)acrylic resin (A) is, for example, 0 to 30 parts by weight (for example, 1 to 25 parts by weight) ), preferably 3 to 20 parts by weight, more preferably 5 to 15 parts by weight.

(Meth) acrylic resin (A) in addition to containing hydroxyl-containing (meth)acrylate (a1) and (a2), alkyl acrylate (a3) and substituted In addition to the structural unit of the alkyl acrylate (a4), the structural unit derived from another monomer (a5) can also be contained. Other single systems can be used alone or in combination of two or more kinds. Examples of other monomers (a5) include monomers having polar functional groups other than hydroxyl groups (a5-1), acrylamide-based monomers (a5-2), and methacrylates (methacrylates). (a5-3), methacrylamide-based monomer (a5-4), styrene-based monomer (a5-5), vinyl-based monomer (a5-6), and having a plurality of (formaldehyde) in the molecule Base) acryl monomer (a5-7) and so on.

Examples of the monomer (a5-1) having a polar functional group other than a hydroxyl group include (meth)acrylates having a substituent such as a carboxyl group, a substituted or unsubstituted amino group, and a heterocyclic group such as an epoxy group. Specifically, acrylomorpholine, vinyl caprolactam, N-vinyl-2-pyrrolidone, vinyl pyridine, tetrahydrofurfuryl (meth)acrylate, caprolactone modified Monomers with heterocyclic groups such as tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexyl methyl (meth)acrylate, glycidyl (meth)acrylate, 2,5-dihydrofuran, etc.; Yl)aminoethyl acrylate, N,N-dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate and other monomers with substituted or unsubstituted amino groups; (Meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, carboxyalkyl (meth)acrylate (e.g. carboxyethyl (meth)acrylate, (meth) Carboxypentyl acrylate) and other monomers having a carboxyl group. These single systems can be used alone or in combination of two or more. In addition, from the viewpoint of preventing deterioration of the releasability of the separation film that can be laminated on the adhesive layer, it is preferable that the structural unit derived from a monomer having an amine group is not substantially contained. In addition, the term "substantially not contained" means that it is less than 1.0 part by weight with respect to 100 parts by weight of the total structural units constituting the (meth)acrylic resin (A).

In the present invention, even if it does not contain a structural unit derived from a monomer having a carboxyl group (a structural unit derived from a carboxyl-containing (meth)acrylate) that is believed to increase the corrosiveness of ITO, it exhibits high durability. Performance, so it can have both durability and ITO corrosion resistance.

On the other hand, when a structural unit derived from a monomer having a carboxyl group [a structural unit derived from a (meth)acrylate containing a carboxyl group] is contained, durability can be further improved. In the present invention, even if the ratio of the structural unit derived from the carboxyl group-containing (meth)acrylate is small, the durability can be effectively improved. Therefore, the durability can be improved while suppressing the corrosion of ITO.

The ratio of the structural unit derived from the carboxyl group-containing (meth)acrylate relative to 100 parts by weight of the structural unit derived from the (meth)acrylate is, for example, 5.0 parts by weight or less (for example, 0 to 3 parts by weight), preferably 1.0 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), still more preferably 0.3 parts by weight or less (for example, 0.005 to 0.3 parts by weight), especially 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). When it is less than the upper limit, ITO corrosivity can be suppressed, and when it is more than the lower limit, durability can be improved.

Examples of the acrylamide-based monomer (a5-2) include N-methylol acrylamide, N-(2-hydroxyethyl) acrylamide, and N-(3-hydroxypropyl) acrylamide. Amine, 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- Pendant oxybutyl) acrylamide, N-[2-(2-side (Oxy-1-imidazolidinyl) ethyl) acrylamide, 2-propenylamino-2-methyl-1-propanesulfonic acid, N-(methoxymethyl)acrylamide, N- (Ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(1-methylethoxymethyl)acrylamide, N-(1-methylpropoxy) Methyl)acrylamide, N-(2-methylpropoxymethyl)acrylamide [alias: N-(isobutoxymethyl)acrylamide], N-(butoxymethyl) ) Acrylamide, N-(1,1-dimethylethoxymethyl) acrylamide, N-(2-methoxyethyl) acrylamide, N-(2-ethoxyethyl) ) Acrylamide, N-(2-propoxyethyl) acrylamide, N-[2-(1-methylethoxy)ethyl] acrylamide, N-[2-(1-methyl Propoxy) ethyl] acrylamide, N-[2-(2-methylpropoxy) ethyl] acrylamide [alias: N-(2-isobutoxyethyl) acrylamide ], N-(2-butoxyethyl)acrylamide, N-[2-(1,1-dimethylethoxy)ethyl]acrylamide, etc. Among them, N-(methoxymethyl)acrylamide, N-(ethoxymeth)acrylamide, N-(propoxymeth)acrylamide, N-(butoxy Phenylmeth)acrylamide, N-(2-methylpropoxymeth)acrylamide, etc. are preferred.

Examples of methacrylic acid ester (a5-3) include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, and n-octyl methacrylate. Ester, lauryl methacrylate and other linear alkyl methacrylates; isobutyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate and other methacrylic acid branched chains Alkyl ester; isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentyl methacrylate, cyclododecyl methacrylate, methylcyclohexyl methacrylate, trimethylcyclohexyl methacrylate Methyl esters, tert-butylcyclohexyl methacrylate, cyclohexylphenyl methacrylate, etc. Mono- or dicycloalkyl acrylate; alkoxyalkyl methacrylate such as 2-methoxyethyl methacrylate, ethoxymethyl methacrylate, etc.; methacrylic aryl such as benzyl methacrylate Alkyl esters and so on.

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

As the styrene monomer (a5-5), for example, styrene; methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl Alkyl styrenes such as styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene; fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, Halogenated styrene such as iodostyrene; nitrostyrene; acetoxystyrene; methoxystyrene; divinylbenzene, etc.

Examples of vinyl monomers (a5-6) include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl laurate and other fatty acid vinyl esters; vinyl chloride , Vinyl bromide and other halogenated vinyl; vinylidene chloride and other halogenated vinylidene; vinyl pyridine, vinyl pyrrolidone, vinyl carbazole and other nitrogen-containing aromatic vinyl; butadiene, isoprene, chlorine Conjugated diene monomers such as butadiene; unsaturated nitriles such as acrylonitrile and methacrylonitrile.

As the monomer (a5-7) having a plurality of (meth)acrylic acid groups in the molecule, for example, 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)acrylic acid Ester, tetraethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate and other monomers having two (meth)acrylic acid groups in the molecule; trimethylolpropane tri(methyl) ) Monomers such as acrylic esters having 3 (meth)acrylic acid groups in the molecule.

In addition, from the viewpoint of the reworkability of the adhesive layer, the (meth)acrylic resin (A) is derived from methacrylate (methacrylate) (a5-3), methacrylamide It is preferable that the ratio (or content) of the structural unit of the methacrylic monomer such as the monomer (a5-4) is smaller. That is, with respect to 100 parts by weight of the total structural units constituting the (meth)acrylic resin (A), the ratio of the structural units is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, and particularly may be 1 part by weight The following.

Furthermore, the ratio of the structural unit derived from the other monomer (a5) relative to 100 parts by weight of the total structural unit constituting the (meth)acrylic resin (A) may be, for example, 0 to 20 parts by weight, and is preferably 0 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).

(Meth)acrylic resin (A) whose weight average molecular weight (Mw) obtained by gel permeation chromatography (GPC) converted from standard polystyrene is, 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 (for example, 1.3×10 ⁶ to 1.6×10 ⁶ ) Range. When Mw is less than the upper limit, it is advantageous from the viewpoint of coatability when the adhesive composition is applied to the substrate. When Mw is more than the lower limit, it is advantageous to improve the optical properties of the adhesive layer. The followability of the dimensional changes of the film. The molecular weight distribution expressed as the ratio of the weight average molecular weight Mw to the number average molecular weight Mn (Mw/Mn) is usually 2-10, preferably 3-8, more preferably 4-6.

In addition, the Mw of the (meth)acrylic resin (A) on the discharge curve of GPC preferably has a single peak in the range of ^{1.0×10 3} to 2.5×10 ^6. When the (meth)acrylic resin (A) with this number of peaks is 1 is used, it is advantageous to improve the durability of the adhesive layer.

Within the above range of the obtained discharge curve, the so-called "having a single peak" means that there is only one maximum value in the range of ^{Mw 1.0×10 3} to 2.5×10 ^6. In this specification, the spectrum peak is defined as the S/N ratio in the GPC discharge curve of 30 or more. In addition, the number of peaks of the GPC discharge curve and the Mw and Mn of the (meth)acrylic resin (A) can be determined by the GPC measurement conditions described in the section of the examples.

When the (meth)acrylic resin (A) is dissolved in ethyl acetate and forms a solution with a concentration of 20% by weight, its viscosity at 25°C is 20Pa. s or less is better, 0.1 to 7Pa. s is better. When the viscosity is in this range, it is advantageous from the viewpoint of coatability when the adhesive composition is applied to the substrate. In addition, the viscosity can be measured with a Brookfield viscometer.

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

(Meth) acrylic resin (A) can be polymerized by, for example, solution polymerization It can be produced by well-known methods such as bulk polymerization, suspension polymerization, and emulsion polymerization. In particular, the solution polymerization method is preferred. As a solution polymerization method, for example, a monomer and an organic solvent are mixed, a thermal polymerization initiator is added in a nitrogen atmosphere, and stirring is performed under a temperature condition of about 40 to 90°C (preferably 50 to 80°C). It takes about 15 hours. In order to control the reaction, the monomer and the thermal polymerization initiator may be added continuously or intermittently during the polymerization. The monomer and thermal initiator can also be added to the organic solvent.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, and the like can be used. As a photopolymerization initiator, 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone etc. are mentioned, for example. As the thermal polymerization initiator, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclo Hexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxy Valeronitrile), dimethyl-2,2'-azobis(2-methylpropionate), 2,2'-azobis(2-hydroxymethylpropionitrile) and other azo compounds ; Laurel peroxide, tertiary butyl hydroperoxide, benzyl peroxide, tertiary butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, diisopropyl peroxydicarbonate Organic peroxides such as propyl ester, tert-butyl peroxyneodecanoate, tert-butyl peroxytrimethylacetate, and peroxide (3,5,5-trimethylhexyl); potassium persulfate , Ammonium persulfate, hydrogen peroxide and other inorganic peroxides. In addition, it is also possible to use a redox-based initiator obtained by using a peroxide and a reducing agent in combination.

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. Polymerization of (meth)acrylic resins can also be used by active energy Polymerization method performed by measuring lines (such as ultraviolet rays, etc.).

Examples of organic solvents include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propanol and isopropanol; acetone and methyl ethyl Ketones such as ketone, methyl isobutyl ketone, etc.

[1-2] Crosslinking agent (B)

The adhesive composition contains a crosslinking agent (B). The crosslinking agent (B) reacts with the hydroxyl-containing polar functional group in the (meth)acrylic resin (A).

The crosslinking agent (B) is an additive compound obtained by adding a toluene diisocyanate compound and/or a toluene diisocyanate compound with a polyol compound (for example, glycerin, trimethylolpropane, etc.). Examples of the toluene diisocyanate compound include monomethylbenzene diisocyanate such as 2,6-toluene diisocyanate, 2,4-toluene diisocyanate, and 3,5-toluene diisocyanate. In the present invention, the OH group (hydroxyl group) of the hydroxyalkyl group having different carbon chain lengths (n and m) introduced into the side chain of the (meth)acrylic resin (A) and the crosslinking agent (B) ) Will react to form a cross-linked structure that is beneficial to durability and reworkability. In particular, because the crosslinking agent (B) is composed of the toluene diisocyanate compound and/or the polyol compound of the toluene diisocyanate compound, it can be estimated that the balance between strength and flexibility (flexibility) is more excellent The cross-linked structure can further improve durability. That is, not only when it is applied to a glass substrate, but also when it is applied (laminated) to an ITO substrate, it can also exhibit high durability. In addition, because the crosslinking agent (B) is an isocyanate compound, from the viewpoint of the crosslinking speed and the usable time of the adhesive composition In terms of it, it is also advantageous.

Relative to 100 parts by weight of the (meth)acrylic resin (A), the ratio of the crosslinking agent (B) may be, for example, 0.01 to 10 parts by weight (for example, 0.05 to 5 parts by weight), preferably 0.1 to 3 parts by weight (E.g., 0.1 to 2 parts by weight), more preferably 0.2 to 1 part by weight (e.g., 0.3 to 0.8 parts by weight). The smaller the upper limit value is, the more advantageous it is to improve the compliance (or peeling resistance), and the larger the lower limit value is, it is advantageous to improve the cohesion resistance (or foaming resistance) and reworkability.

[1-3] Silane compound (C)

The adhesive composition contains a silane compound (C). By containing the silane compound (C), the adhesion (or adhesion) of the adhesive layer, the metal layer, the transparent electrode, the glass substrate, etc. can be improved. The silane compound (C) may be any silane compound capable of bonding to the reactive group (for example, the OH group of the hydroxyl group) of the (meth)acrylic resin (A), for example, vinyl trimethoxy silane , Vinyl triethoxy silane, vinyl ginseng (2-methoxyethoxy) silane, 3-glycidoxy propyl trimethoxy silane, 3-glycidoxy propyl triethoxy silane , 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsiloxane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxy Silane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-hydrothiopropyltrimethoxysilane Silane, and 1,3-bis(3'-trimethoxypropyl)urea, etc.

In addition, the silane compound (C) may be a polysiloxane oligomer type compound. When the polysiloxane oligomer is described as a combination of monomers, for example, 3-hydrothiopropyl bis or Trimethoxysilane-tetramethoxysilane Oligomers, 3-Hydroxythiomethyl bis or trimethoxy silane-tetraethoxy silane oligomers, 3-Hydroxy propyl bis or triethoxy silane-tetramethoxy silane oligomers , 3-Hydroxythiomethyldi or triethoxysilane-tetraethoxysilane oligomers and other oligomers containing hydrogensulfanyl alkyl groups; the oligomers of the hydrogensulfanylalkyl group-containing oligomers An oligomer formed by replacing the hydrosulfanyl alkyl group with other substituents [3-glycidoxypropyl, (meth)acryloxypropyl, vinyl, amino, etc.].

The silane compound (C) may preferably be a silane compound represented by the following formula (c1). When the adhesive composition contains a silane compound represented by the following formula (c1), the adhesiveness (or adhesion) can be further improved, so that an adhesive layer having excellent peeling resistance can be formed. Moreover, the adhesive layer also has excellent reworkability. In particular, even when the adhesive layer is applied to a transparent electrode (for example, an ITO substrate, etc.) under a high-temperature environment, it is possible to maintain adhesion (or adhesion) and exhibit high durability.

(式中，B係表示碳數1至20的烷二基或碳數3至20的二價脂環式烴基，構成前述烷二基及前述脂環式烴基之-CH₂-亦置換成-O-或-CO-，R¹係表示碳數1至5的烷基，R²、R³、R⁴、R⁵及R⁶係各自獨立地表示碳數1至5的烷基或碳數1至5的烷氧基)

(In the formula, B represents an alkanediyl group having 1 to 20 carbons or a divalent alicyclic hydrocarbon group having 3 to 20 carbons, and -CH ₂ -constituting the alkanediyl group and the aforementioned alicyclic hydrocarbon group is also replaced with- O- or -CO-, R ¹ represents an alkyl group having 1 to 5 carbons, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 5 carbons or a carbon number 1 to 5 alkoxy)

In the formula (c1), B series represents methylene, ethylene, trimethylene, tetramethylene, hexamethylene, heptamethylene, octamethylene and other alkane 2 having 1 to 20 carbon atoms. Group; cyclobutylene (for example, 1,2-cyclopentyl), cyclopentyl (for example, 1,2-cyclopentyl, cyclohexylene (for example, 1,2-cyclohexyl), cyclooctyl Divalent alicyclic hydrocarbon groups with 3 to 20 carbon atoms such as 1,2-cyclooctyl groups; or -CH ₂ -constituting the alkanediyl group and the aforementioned alicyclic hydrocarbon group is replaced with -O- or -CO- group. Preferably, B is an alkanediyl group having 1 to 10 carbon atoms. R ¹ is a methyl group, ethyl group, propyl group, isopropyl group, butyl group, second butyl group, and tertiary butyl group. ^{R 2} , R ³ , R ⁴ , R ^5, and R ⁶ are each independently an alkyl group having 1 to 5 carbon atoms, such as pentyl group, etc., and represent the alkyl group having 1 to 5 carbon atoms as exemplified in the foregoing R ^{1; or methoxy} Group, ethoxy, propoxy, isopropoxy, butoxy, second butoxy, tertiary butoxy and other alkoxy groups having 1 to 5 carbon atoms. Preferred R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are alkoxy groups having a carbon number of 1 to 5. These silane compounds (C) can be used alone or in combination of two or more kinds.

Specific examples of the silane compound (c1) include (trimethoxysilyl)methane, 1,2-bis(trimethoxysilyl)ethane, and 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(trimethoxysilyl)pentane, 1,5-bis(triethoxysilyl)pentane, 1,6-bis( Trimethoxysilyl)hexane, 1,6-bis(triethoxysilyl)hexane, 1,6-bis(tripropoxysilyl)hexane, 1,8-bis(trimethoxy) Silyl)octane, 1,8-bis(triethoxysilyl)octane, 1,8-bis(tripropoxysilyl)octane and other bis(tri-C _1-5 alkoxysilica) Group) C _1-10 alkane; bis(dimethoxymethylsilyl)methane, 1,2-bis(dimethoxymethylsilyl)ethane, 1,2-bis(dimethoxyethyl) Silyl)ethane, 1,4-bis(dimethoxymethylsilyl)butane, 1,4-bis(dimethoxyethylsilyl)butane, 1,6-bis(dimethoxyethylsilyl)butane, Methoxymethylsilyl)hexane, 1,6-bis(dimethoxyethylsilyl)hexane, 1,8-bis(dimethoxymethylsilyl)octane, 1,8 _{-Bis(di-C 1-5} alkoxy C _1-5 alkyl silyl) C _1-10 alkane such as bis(dimethoxyethylsilyl)octane; 1,6-bis(methoxy) Dimethylsilyl)hexane, 1,8-bis(methoxydimethylsilyl)octane and other bis(mono-C _1-5 alkoxy-di C _1-5 alkylsilyl) C _1-10 alkanes and so on. Among them, 1,2-bis(trimethoxysilyl)ethane, 1,3-bis(trimethoxysilyl)propane, 1,4-bis(trimethoxysilyl)butane, 1,5-bis(trimethoxysilyl)pentane, 1,6-bis(trimethoxysilyl)hexane, 1,8-bis(trimethoxysilyl)octane and other bis(triC) _1-3 alkoxysilyl) C _1-10 alkane is preferred, 1,6-bis(trimethoxysilyl)hexane and 1,8-bis(trimethoxysilyl)octane are particularly preferred .

The ratio of the silane compound (C) relative to 100 parts by weight of the (meth)acrylic resin (A) is, for example, 0.01 to 10 parts by weight (for example, 0.03 to 5 parts by weight), preferably 0.05 to 3 parts by weight, more preferably It is 0.1 to 1 part by weight (for example, 0.2 to 0.5 part by weight). When the value is below the upper limit, it is advantageous to suppress the exudation of the silane compound (C) from the adhesive layer. When the value is above the lower limit, the adhesion (or adhesion) of the adhesive layer, metal layer, glass substrate, etc. Lifting becomes easy, and it is advantageous for improving peeling resistance and the like.

[1-4] Antistatic agent

The adhesive composition may further contain an antistatic agent. By containing an antistatic agent, the antistatic property of the adhesive can be improved (for example, it is possible to suppress defects caused by static electricity generated when a release film, a protective film, etc. are peeled off). Examples of the antistatic agent include conventional ones, and ionic antistatic agents are preferred. Examples of cationic components constituting the ionic antistatic agent include organic cations and inorganic cations. As an organic cation, a pyridinium cation, an imidazolium cation, an ammonium cation, a sulfonium cation, a phosphonium cation, etc. are mentioned, for example. Examples of inorganic cations 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 anion component constituting the ionic antistatic agent can be either inorganic anion or organic anion. In terms of excellent antistatic performance, an anion component containing fluorine atoms is preferred. As an anion component containing a fluorine atom, for example, hexafluorophosphate anion (PF _6- ), bis(trifluoromethanesulfonyl)imine anion [(CF ₃ SO ₂ ) ₂ N-], bis(fluorine Sulfonyl)imine anion [(FSO ₂ ) ₂ N-], tetrakis(pentafluorophenyl) borate anion [(C ₆ F ₅ ) ₄ B-], etc. These antistatic agents can be used alone or in combination of two or more kinds. Especially bis(trifluoromethanesulfonyl) imine anion [(CF ₃ SO ₂ ) ₂ N-], bis(fluorosulfonyl) imine anion [(FSO ₂ ) ₂ N-], four (five Fluorophenyl) borate anion [(C ₆ F ₅ ) ₄ B-] is preferred.

In terms of the antistatic properties of the adhesive composition and its excellent stability over time, ionic antistatic agents that are solid at room temperature are preferred.

The ratio of the antistatic agent relative to 100 parts by weight of the (meth)acrylic resin (A) can be, for example, 0.01 to 10 parts by weight, preferably 0.1 to 5 parts by weight, more preferably 1 to 3 parts by weight.

[1-5] Other ingredients

The adhesive composition can contain two or more solvents, crosslinking catalysts, ultraviolet absorbers, weather stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, inorganic fillers, Additives such as light-scattering fine particles. Also, for the formulation of the adhesive composition After forming the adhesive layer with the ultraviolet curable compound, it is also useful to irradiate the ultraviolet ray to harden the adhesive layer to become a harder adhesive layer. Examples of crosslinking catalysts include hexamethylene diamine, ethylene diamine, polyethyleneimine, hexamethylene tetramine, ethylene triamine, triethylene tetramine, isophorone diamine, Amine compounds such as trimethylene diamine, polyamine-based resin, and melamine resin.

From the viewpoint of improving the metal corrosion resistance of the adhesive layer, the adhesive composition system can contain a rust inhibitor. Examples of the rust inhibitor include triazole-based compounds such as benzotriazole-based compounds; thiazole-based compounds such as benzothiazole-based compounds; imidazole-based compounds such as benzyl imidazole-based compounds; imidazoline-based compounds; Quinoline-based compounds; pyridine-based compounds; pyrimidine-based compounds; indole-based compounds; amine-based compounds; urea-based compounds; sodium benzoate; benzyl sulfide-based compounds; di-second butyl sulfide; and diphenyl Keaqi et al.

[2] The composition and manufacturing method of the adhesive layer and the optical film with the adhesive layer

The adhesive composition system of the present invention can form an adhesive layer by performing surface activation treatment (for example, plasma treatment, corona treatment, etc.). Usually, the adhesive layer is laminated on at least one side of the optical film.

Fig. 1 is a schematic cross-sectional view showing an example of an optical film with an adhesive layer formed of the adhesive composition of the present invention. The optical film 1 with an adhesive layer shown in FIG. 1 is an optical film 10 and an optical film formed by laminating an adhesive layer 20 on one side of the optical film. The adhesive layer 20 is usually directly laminated on the surface of the optical film 10. In addition, the adhesive layer 20 may be laminated on both sides of the optical film 10.

When the adhesive layer 20 is laminated on the surface of the optical film 10, the primer layer is formed on the bonding surface of the optical film 10 and/or the bonding surface of the adhesive layer 20, or the aforementioned surface activation treatment ( For example, plasma treatment, corona treatment, etc.) is preferred, and corona treatment is particularly preferred.

When the optical film 10 protects the polarizer on one side as shown in Figure 2, the adhesive layer 20 is usually laminated (preferably directly laminated) on the surface of the polarizer, that is, laminated on the polarizer 2 and the first resin film 3 is the opposite side. When the optical film 10 protects the polarizing plate on both sides as shown in Figure 3, the adhesive layer 20 can be laminated on the outer surface of any one of the first and second resin films 3, 4, or on both sides The outer surface.

An antistatic layer can also be additionally provided between the optical film 10 and the adhesive layer 20. As the antistatic layer, silicon-based materials such as polysiloxane, inorganic metal-based materials such as tin-doped indium oxide, tin-doped antimony oxide, and organic polymers such as polythiophene, polystyrene sulfonic acid, and polyaniline can be used. Molecular materials.

The adhesive layer-attached optical film 1 may also include a separation film (release film) laminated on the outer surface of the adhesive layer 20. The separation film is usually peeled and removed when the adhesive layer 20 is used (for example, when it is laminated on a transparent conductive electrode and a glass substrate). The separation film may be, for example, the surface where the adhesive layer 20 is to be formed on a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyarylate, etc. Those who perform mold release treatment such as silicone treatment.

The adhesive layer-attached optical film 1 can be formed by dissolving or dispersing the components constituting the above-mentioned adhesive composition in a solvent. The adhesive composition of the solvent is then obtained by coating the surface of the optical film 10 and drying to form the adhesive layer 20. In addition, the optical film 1 with an adhesive layer can also be formed by forming the adhesive layer 20 on the release treatment surface of the release film in the same manner as described above, and laminating (transferring) the adhesive layer 20 on the optical film 10 surface to get.

The thickness of the adhesive layer is usually 2 to 40 μm. From the viewpoints of the durability of the optical film with the adhesive layer and the reworkability of the optical film with the adhesive layer, it is preferably 5 to 30 μm, and more preferably 10 to 25μm. When it is below the upper limit, the followability (or followability) of the adhesive layer to the dimensional change of the optical film becomes good, and when it is above the lower limit, the reworkability becomes good.

The adhesive layer is preferably one that exhibits a storage elastic modulus of 0.1 to 5 MPa in a temperature range of 23 to 80°C. Thereby, the durability of the optical film with the adhesive layer can be more effectively improved. The so-called "showing a storage elastic modulus of 0.1 to 5 MPa in the temperature range of 23 to 80°C" means that at any temperature within this range, the storage elastic modulus is a value within the above range. Because the storage elastic modulus usually decreases as the temperature rises, as long as the storage elastic modulus at 23°C and 80°C is within the above range, it can be assumed that the temperature in this range can display the storage elastic modulus in the above range. number. The storage elastic modulus of the 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 crosslink density. Because the adhesive layer formed by the adhesive composition of the present invention is It has a predetermined crosslink density, so it will show a predetermined gel fraction. That is, the gel fraction of the adhesive layer can be, 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), more preferably It is 70 to 85% by weight (for example, 80 to 85% by weight). When the gel fraction is higher than the lower limit, it is advantageous for the foaming resistance (resistance to agglomeration destruction) and reworkability of the adhesive layer, and when the gel fraction is lower than the upper limit, it is advantageous for the peeling resistance. . In addition, the gel fraction can be measured by the method described in the example section.

The adhesive layer formed by the adhesive composition of the present invention has a predetermined adhesive force. That is, the adhesive layer is attached to a glass substrate, and the adhesive force of the adhesive layer after 24 hours under the conditions of a temperature of 23° C. and a relative humidity of 50% is set at a peeling speed of 300 mm/min. It is 0.5 to 25N (for example, 0.5 to 20N), preferably 0.5 to 10N (for example, 1 to 10N), and more preferably 1 to 8N. When the adhesive force is higher than the lower limit value, the adhesiveness (or adhesiveness) is improved and is advantageous for peeling resistance, etc., and when the adhesive force is lower than the upper limit value, it is advantageous for reworkability. In addition, the adhesive force can be measured by the method described in the Examples.

[2-1] Optical film

The optical film 10 constituting the adhesive layer-attached optical film 1 may also be various optical films (films having optical characteristics) that can be incorporated in image display devices such as liquid crystal display devices. The optical film 10 can be a single-layer structure (such as a polarizer, a retardation film, a brightness enhancement film, an anti-glare film, an anti-reflection film, a diffuser film, a light-concentrating film, etc.), or a multilayer structure (For example, polarizing plate, phase difference plate, etc.). Optical film 10 series with polarized light Plates, polarizers, retardation plates or retardation films are preferred, and polarizers or polarizers are particularly preferred. In addition, in this specification, the term "optical film" means a film for achieving the function of image display (display screen, etc.) (for example, a film for achieving the function of enhancing the clarity of the image). In addition, in this specification, the term "polarizing plate" means a resin film or resin layer laminated on at least one side of the polarizer, and the term "phase difference plate" means laminating a resin film or resin layer on the retardation film. At least one side of a person.

[2-2] Polarizing plate

2 and 3 are schematic cross-sectional views showing examples of the layer structure of the polarizing plate. The polarizing plate 10a shown in Figure 2 is formed by laminating (or laminating) the first resin film 3 on one side of the polarizer 2 to form a protective polarizing plate, while the polarizing plate 10b shown in Figure 3 is Furthermore, the second resin film 4 is laminated (or laminated and bonded) on the other side of the polarizer 2 to protect the polarizing plate on both sides. The first and second resin films 3 and 4 can be attached to the polarizer 2 through an adhesive layer or an adhesive layer not shown. In addition, the polarizing plates 10a, 10b may include other films or layers other than the first and second resin films 3, 4.

The polarizer 2 is a film with the following properties: that is, it absorbs linearly polarized light with a vibration plane parallel to its absorption axis, and transmits linearly polarized light with a vibration plane orthogonal to the absorption axis (parallel to the penetration axis); For example, a film obtained by arranging and adsorbing a dichroic dye on a polyvinyl alcohol-based resin film can be used. Examples of dichroic dyes include iodine and dichroic organic dyes.

Polyvinyl alcohol-based resins can be Obtained by saponification of ester resin. Examples of polyvinyl acetate resins include polyvinyl acetate which is a homopolymer of vinyl acetate, and monomers that can be copolymerized with vinyl acetate (for example, unsaturated carboxylic acids, olefins, vinyl ethers, non-saturated carboxylic acids, olefins, vinyl ethers, etc.). Saturated sulfonic acid, (meth)acrylamide with ammonium group, etc.) and vinyl acetate copolymer.

The degree of saponification of the polyvinyl alcohol-based resin is generally 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol resin may also be modified, for example, polyvinyl formaldehyde or polyvinyl acetal modified by aldehydes. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1,000 to 10,000, preferably 1,500 to 5,000. In addition, the average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

Usually, a film made of a polyvinyl alcohol-based resin is used as the embryonic film of the polarizer 2. The polyvinyl alcohol-based resin system can be formed into a film by a well-known method. The thickness of the embryonic membrane is usually 1 to 150 μm, and it is preferably 10 μm or more in consideration of ease of extension and the like.

The polarizer 2 is, for example, a step of uniaxially extending the embryonic membrane, a step of dyeing the film with a dichroic pigment to adsorb the dichroic pigment, a step of treating the film with an aqueous solution of boric acid, and washing the film with water. Step, finally drying and manufacturing. The thickness of the polarizer 2 is usually 1 to 30 μm, and from the viewpoint of thinning the optical film 1 with the adhesive layer, it is preferably 20 μm or less; more preferably 15 μm or less, particularly 10 μm or less.

The polarizer 2 formed by adsorbing and aligning the dichroic dye on the polyvinyl alcohol resin film can be obtained by the following methods: 1) Use A single film of a polyvinyl alcohol-based resin film is used as an embryo film, and the film is subjected to a uniaxial stretching treatment and a method of dyeing a dichroic pigment; and 2) a coating solution (aqueous solution, etc.) containing a polyvinyl alcohol-based resin After coating on a base film and drying to obtain a base film with a polyvinyl alcohol-based resin layer, it is uniaxially stretched together with the base film, and the stretched polyvinyl alcohol-based resin layer is subjected to two colors The dyeing treatment of sex pigments, followed by the method of peeling and removing the substrate film. As the base film, a film made of the same thermoplastic resin as the thermoplastic resin capable of forming the first and second resin films 3, 4 described later can be used, preferably made of polyethylene terephthalate or the like. Films composed of polyester resins, polycarbonate resins, cellulose resins such as cellulose triacetate, cyclic polyolefin resins such as norbornene resins, and polystyrene resins. When the method of 2) above is used, it becomes easy to manufacture the polarizer 2 of a thin film, for example, it becomes easy to manufacture the polarizer 2 having a thickness of 7 μm or less.

The first and second resin films 3, 4 may be independently transparent thermoplastic resins, preferably optically transparent thermoplastic resins, such as chain polyolefin resins (polyethylene resins, poly Polyolefin resins such as propylene resins, etc.), cyclic polyolefin resins (norbornene resins, etc.); cellulose resins (cellulose ester resins, etc.); polyester resins (polyterephthalic acid) Ethylene glycol, polyethylene naphthalate, polybutylene terephthalate, etc.); polycarbonate resins (such as 2,2-bis(4-hydroxyphenyl) propane, etc.) derived from bisphenol Carbonate, etc.); (meth)acrylic resins; polystyrene resins; polyetheretherketone resins; polysulfite resins, or films composed of such mixtures and copolymers. Among them, the first and second trees The grease films 3 and 4 are preferably films composed of cyclic polyolefin resins, polycarbonate resins, cellulose resins, polyester resins, and (meth)acrylic resins. A film made of cellulose resin, cyclic polyolefin resin, etc. is particularly preferred.

Examples of chain polyolefin resins include homopolymers of chain olefins such as polyethylene resins and polypropylene resins, copolymers composed of two or more chain olefins, and the like.

Cyclic polyolefin-based resins are a general term for resins containing cyclic olefins as representative examples of norbornene, tetracyclododecene (alias: dimethyl octahydronaphthalene) or derivatives thereof as polymerized units. Examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins and their hydrogenated products, addition polymers of cyclic olefins, cyclic olefins and chain olefins such as ethylene and propylene, or those having ethylene Copolymers of aromatic compounds based on the base, and these modified (co)polymers modified by unsaturated carboxylic acids or their derivatives. Among these, a norbornene-based resin using a norbornene-based monomer such as a norbornene and a polycyclic norbornene-based monomer as a cyclic olefin is preferred.

The cellulose resin is preferably a cellulose ester resin, that is, a partial or complete esterification of cellulose. Examples include acetate, propionate, butyrate, and mixed esters of cellulose. . Among them, cellulose triacetate, cellulose diacetate, cellulose acetate propionate, cellulose acetate butyrate, etc. are preferred.

The polyester resin is a resin other than the above-mentioned cellulose ester resin having an ester bond, and is usually composed of a polycondensate of a polycarboxylic acid or a derivative thereof and a polyhydric alcohol. Examples of polyester resins include polymer Ethylene phthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, poly Cyclohexane dimethyl terephthalate, polycyclohexane dimethyl naphthalate, etc.

The polycarbonate resin is a polyester formed from carbonic acid and glycol or bisphenol. Among these, from the viewpoints of heat resistance, weather resistance, and acid resistance, aromatic polycarbonates having diphenylalkanes in the molecular chain are preferred. Examples of polycarbonates include 2,2-bis(4-hydroxyphenyl)propane (alias bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis Polycarbonate derived from bisphenols such as (4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobutane, 1,1-bis(4-hydroxyphenyl)ethane, etc. Ester etc.

The (meth)acrylic resin that can constitute the first and second resin films 3, 4 can be a polymer having a methacrylate-derived structural unit as the main body (for example, containing 50% by weight or more), and It is better to copolymerize with other copolymerization components.

The (meth)acrylic resin may contain two or more types of structural units derived from methacrylate. _{Examples of methacrylates include C 1} to C ₄ alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate.

As a copolymerization component which can be copolymerized with methacrylate, an acrylate can be mentioned. _{The acrylate is preferably a C 1} to C ₈ alkyl ester of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Specific examples of other copolymerization components include unsaturated acids such as (meth)acrylic acid; aromatic vinyl compounds such as styrene, halogenated styrene, α-methylstyrene, and vinyl toluene; Base) vinyl cyanide compounds such as acrylonitrile; unsaturated acid anhydrides such as maleic anhydride and citraconic acid anhydride; unsaturated acid anhydrides such as phenyl maleimide and cyclohexyl maleimide Compounds other than acrylate having one polymerizable carbon-carbon double bond in the molecule, such as imine. A compound having two or more polymerizable carbon-carbon double bonds in the molecule can also be used as a copolymerization component. The copolymerization component system can be used individually or in combination of 2 or more types.

In terms of improving the durability of the film, the (meth)acrylic resin may have a ring structure in the polymer main chain. The ring structure is preferably a heterocyclic structure such as a cyclic anhydride structure, a cyclic imine structure, and a lactone ring structure. Specific examples of the cyclic acid anhydride structure include a glutaric anhydride structure, a succinic anhydride structure, and the like. Examples of a cyclic anhydride structure include a Glutarimide structure and a succinimide structure. The structure, etc., as specific examples of the lactone ring structure, a butyrolactone ring structure, a valerolactone ring structure, and the like can be given.

The (meth)acrylic resin may contain acrylic rubber particles from the viewpoints of film-forming properties of the film, impact resistance of the film, and the like. The so-called acrylic rubber particles are particles that have an elastic polymer mainly composed of acrylate as an essential component. Examples include those having substantially only a single-layer structure composed of the elastic polymer, or the elastic polymer as 1 Layers of multi-layer structure. As an example of the elastic polymer, a crosslinked elastic copolymer obtained by copolymerizing an alkyl acrylate as a main component with another vinyl monomer and a crosslinkable monomer that can be copolymerized can be mentioned. _{As the alkyl acrylate which is the main component of the elastic polymer, for example, a C 1} to C ₈ alkyl acrylate of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate can be cited. The carbon number of the alkyl group is preferably 4 or more.

As other vinyl monomers that can be copolymerized with alkyl acrylate, compounds having one polymerizable carbon-carbon double bond in the molecule can be cited, and more specifically, methyl methacrylate such as methyl methacrylate can be cited. Acrylates, aromatic vinyl compounds such as styrene, vinyl cyanide compounds such as (meth)acrylonitrile, etc. As the crosslinkable monomer, a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule can be cited, and more specifically, ethylene glycol di(meth)acrylate, butane diacrylate can be cited. (Meth)acrylates of polyhydric alcohols such as alcohol di(meth)acrylate, alkenyl esters of (meth)acrylic acid such as allyl (meth)acrylate, divinylbenzene, and the like.

The content of the acrylic rubber particles is preferably 5 parts by weight or more, preferably 10 parts by weight or more, relative to 100 parts by weight of the (meth)acrylic resin. When the content of acrylic rubber particles is too large, the surface hardness of the film decreases, and when the film is surface-treated, the solvent resistance to the organic solvent in the surface treatment agent decreases. Therefore, 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.

化合物、氰基(甲基)丙烯酸酯化合物、鎳錯鹽等。 The first and second resin films 3 and 4 can contain usual additives in the technical field of the present invention. Examples of additives include ultraviolet absorbers, infrared absorbers, organic dyes, pigments, inorganic dyes, antioxidants, antistatic agents, surfactants, lubricants, dispersants, and heat stabilizers. Examples of ultraviolet absorbers include salicylate compounds, diphenyl ketone compounds, benzotriazole compounds, three

Compounds, cyano (meth)acrylate compounds, nickel aluminum salts, etc.

Each of the first and second resin films 3, 4 may be an unstretched film, or a film stretched uniaxially or biaxially. The first resin film 3 and/or the second resin film 4 may be a protective film that serves as a protection for the polarizer 2, or may be a protective film having an optical function as a retardation film described later. In addition, the first resin film 3 and the second resin film 4 may be the same or different films.

In addition, the first resin film 3 and/or the second resin film 4 may be provided with a hard coat layer, an anti-glare layer, an anti-reflection layer, a light diffusion layer, and an anti-glare layer on its outer surface (the surface opposite to the polarizer 2). Surface treatment layer (coating layer) of electrostatic layer, antifouling layer, conductive layer, etc. The thickness of each of the first resin film 3 and the second resin film 4 is 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), and still more preferably 30 μm or less (for example, 5 to 25 μm).

Especially in the case of small-sized oriented polarizers in smart phones and tablet-type terminal devices, in terms of thin film requirements, most of them use thinner ones with a thickness of 30μm or less as the first resin film 3 and/or second The resin film 4, however, such a polarizing plate has a weak force to suppress the shrinkage of the polarizer 2 and the durability is likely to become insufficient. When such a polarizing plate is used as the optical film 10, the adhesive layer-attached optical film 1 of the present invention also has good durability.

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

As water-based adhesives, conventional water-based adhesives can be cited Agents (for example, adhesives composed of aqueous solutions of polyvinyl alcohol resins, aqueous two-component urethane emulsion adhesives, aldehyde compounds, epoxy compounds, melamine compounds, methylol compounds, isocyanate compounds, amines Compounds, crosslinking agents such as polyvalent metal salts, etc.). Among these, an aqueous adhesive composed of a polyvinyl alcohol-based resin aqueous solution can be suitably used. In addition, when using a water-based adhesive, it is preferable to perform a drying step to remove water contained in the water-based adhesive after bonding the polarizer 2 and the first and second resin films 3, 4 together. After the drying step, an aging step of aging at a temperature of, for example, 20 to 45° C. can also be provided.

The above-mentioned active energy ray curable adhesive refers to an adhesive that is cured by irradiating active energy rays such as ultraviolet rays, electron beams, etc., for example, a curable composition containing a polymerizable compound and a photopolymerization initiator, and The curable composition of a photoreactive resin, a curable composition containing a binder resin and a photoreactive crosslinking agent, etc., are preferably an ultraviolet curable adhesive.

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

As a method of bonding the polarizer 2 to the first and second resin films 3, 4, there may be saponification treatment, corona treatment, plasma treatment, etc., on at least one of the bonding surfaces of the polarizer 2 Activation method Wait. When the resin film is attached to both sides of the polarizer 2, the adhesive used for attaching the resin film may be the same type of adhesive or a different type of adhesive.

The polarizing plates 10a and 10b can further contain other films or layers. Specific examples thereof are retardation films, brightness enhancement films, anti-glare films, anti-reflection films, diffusion films, light-concentrating films, adhesive layers other than the adhesive layer 20, coating layers, protective films, etc. described later. The protective film is used for the purpose of protecting the surface of the optical film 10 such as a polarizing plate from scratches and contamination, and after the optical film 1 with an adhesive layer is attached to, for example, a metal layer or a substrate, it is usually Peel off.

The protective film is usually composed of a base film and an adhesive layer laminated on it. The base film can be made of thermoplastic resins, such as polyolefin resins such as polyethylene resins and polypropylene resins; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; Polycarbonate resin; (meth)acrylic resin, etc.

[2-3] Phase difference plate

The retardation film contained in the retardation plate is an optical film showing optical anisotropy as described above. It can be a stretched film obtained by stretching a resin film to about 1.01 to 6 times. The resin film is made of : In the above examples, the thermoplastic resins that can be used in the first and second resin films 3, 4, and, for example, polyvinyl alcohol-based resins, polyarylate-based resins, polyimide-based resins, and polyether-based resins, Polyvinylidene fluoride/polymethyl methacrylate resin, liquid crystal polyester resin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride resin, etc. These Among them, a stretched film obtained by uniaxially stretching or biaxially stretching a polycarbonate resin film, a cyclic olefin resin film, a (meth)acrylic resin film, or a cellulose resin film is preferable. In addition, in this specification, the zero retardation film is also included in the retardation film (however, it can also be used as a protective film). In addition, films called uniaxial retardation films, wide viewing angle retardation films, and low photoelastic modulus retardation films can also be applied as retardation films.

Called zero retardation value of the retardation value means the surface of the film R _e and the thickness direction retardation R _th value while a film of 15nm to -15. This retardation film system can be suitably used in an IPS mode liquid crystal display device. R _e in-plane retardation value and the thickness direction retardation value R _th lines simultaneously preferably -10 to 10nm, more preferably -5 to simultaneously 5nm. Referred to in this plane retardation value R _e and the thickness direction retardation R _th value of the 590nm wavelength system.

R _e in-plane retardation value and the thickness direction retardation R _th value of each line defined by the following formula:

R _e =(n _x -n _y )×d

R _th =[(n _x +n _y )/2-n _z ]×d

In the formula, n _x is the refractive index in the slow axis direction (x-axis direction) in the _{film plane, and n y} is the refractive index in the fast axis direction (y-axis direction orthogonal to the x-axis in the plane) in the film plane, n _z is the refractive index in the film thickness direction (the z-axis direction perpendicular to the film surface), and d is the film thickness.

In the zero retardation film, for example, polyolefin resins such as cellulose resins, chain polyolefin resins, and cyclic polyolefin resins, polyethylene terephthalate resins, or (methyl) can be used. Acrylic Resin film made of resin. In particular, since the retardation value is easy to control and easy to obtain, it is possible to suitably use cellulose resin, polyolefin resin, or (meth)acrylic resin.

In addition, a film that exhibits optical anisotropy due to coating/alignment of a liquid crystal compound and a film that exhibits optical anisotropy due to coating of an inorganic layered compound can be used as a retardation film. This kind of retardation film includes: what is called temperature compensation type retardation film, and also, JX Nippon Nippon Nippon Oil Energy Co., Ltd. sold under the trade name of "NH FILM" a film with a rod-shaped liquid crystal in an oblique orientation, Fuji Film Co., Ltd. sells a film with obliquely aligned disc-shaped liquid crystals under the brand name "WV FILM", and a fully biaxially oriented film sold under the brand name "VAC FILM" by Sumitomo Chemical Co., Ltd., and the same It is a biaxially oriented film sold by Sumitomo Chemical Co., Ltd. under the brand name "new VAC FILM". In addition, the resin film laminated on at least one surface of the retardation film can be, for example, the above-mentioned protective film.

[3] Optical laminate

FIGS. 4 to 8 are schematic cross-sectional views showing an example of an optical laminate including an optical film with an adhesive layer formed of the adhesive composition of the present invention.

The optical laminate 5 shown in Fig. 4 is a layered optical film 1a (or a polarized light film with an adhesive layer) that has been laminated on a substrate 40 with a metal layer 30 (or metal circuit layer 30) laminated on the aforementioned adhesive layer An optical laminate formed on the surface of the adhesive layer side of the plate 1a). The optical film 1a with the adhesive layer is formed by laminating the adhesive layer 20 on the surface of the polarizing plate 10a on the polarizer 2 side.

The optical laminate 6 shown in Figure 5 is laminated on The metal layer 30 on the substrate 40 is laminated on the surface of the adhesive layer side of the adhesive layer-attached optical film 1b (or the adhesive layer-attached polarizing plate 1b). The said adhesive layer-attached optical film 1b is an optical film which laminated|stacked the adhesive layer 20 on the surface of the 2nd resin film 4 side of the said polarizing plate 10b.

The optical laminates 5 and 6 can be obtained by laminating the optical films (1a, 1b) with the adhesive layer through the adhesive layer 20 to bond the metal layer 30, wherein the metal layer 30 is laminated on the substrate 40 .

As a method of forming the metal layer 30 on the substrate 40, for example, a sputtering method or the like can be cited. The substrate 40 may be a transparent substrate constituting the liquid crystal cell included in the touch input device, and is preferably a glass substrate. As a material of this glass substrate, soda lime glass, low alkali glass, alkali-free glass, etc. 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 of it.

The metal layer 30 may be, for example, a layer containing at least one metal element selected from aluminum, copper, silver, iron, tin, zinc, nickel, molybdenum, chromium, tungsten, lead, and alloys containing these two or more metals. Among them, from the viewpoint of conductivity, a layer containing at least one metal element selected from the group consisting of aluminum, copper, silver, and gold is preferable. From the viewpoint of conductivity and cost, it is preferable to be a layer containing at least one metal element selected from the group consisting of aluminum, copper, silver, and gold. It may be a layer containing aluminum, and more preferably may be a layer containing aluminum as a main component (accounting for more than 50% by weight of the total metal components constituting the metal layer 30).

The metal layer 30 may be, for example, a transparent electrode layer such as ITO (tin-doped indium oxide), or it may have a metal layer 30 and a transparent electrode layer made of ITO. Transparent electrode layer composed of metal oxide. In addition, a metal mesh formed by arranging a thin metal circuit layer on a substrate, or a layer formed by adding metal nanoparticles or metal nanowires to a bonding agent can also be used.

The preparation method of the metal layer 30 is not particularly limited. It may be a metal foil, or may be formed by a vacuum evaporation method, a sputtering method, an ion spraying method, an inkjet printing method, or a gravure printing method. A metal layer formed by a sputtering method, an inkjet printing method, or a gravure printing method is preferable, and a metal layer formed by sputtering is more preferable. The thickness of the metal layer 30 is not particularly limited, and 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. Moreover, when the metal layer 30 is a metal circuit layer (for example, a metal mesh), the line width of the metal circuit is usually 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, and usually 0.5 μm or more.

The optical laminate 7 shown in FIG. 6 is an optical laminate formed by laminating the adhesive layer 20 of the aforementioned adhesive layer-attached optical film 1 on a substrate 40.

The optical laminate 8 shown in Fig. 7 is a resin layer 50 that is further laminated on the surface of the metal layer 30 (on the surface opposite to the substrate 40) that has been laminated on the substrate 40, and is laminated on the aforementioned An optical laminate formed on the surface of the adhesive layer 20 side of the optical film 1 with an adhesive layer. As the resin forming the resin layer 50, for example, the resin constituting the first or second resin film as exemplified above can be cited.

The optical laminate 9 shown in Fig. 8 is in addition to laminating a plurality of metal layers 30 on the substrate 40 in the vertical and horizontal directions at predetermined intervals. In addition to the resin layer 50 formed (or laminated) between the plurality of metal layers 30 (or gaps) and on the surface of the metal layer 30 (on the surface opposite to the substrate 40), the rest is connected to the optical laminate 7 same. In the form of the optical laminate 8 (the form obtained by patterning the metal layer 30 into a predetermined shape), the metal layer 30 may be, for example, a metal circuit layer of a touch input element included in a touch input type liquid crystal display device ( That is the electrode layer).

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

After bonding the optical film (1, 1a, 1b) with the adhesive layer to the substrate 40 (glass substrate, transparent substrate, etc.) or the metal layer 30 (transparent electrode layer) to produce an optical laminate, if some defects occur Sometimes it is necessary to peel the optical film with the adhesive layer from the substrate 40 or the metal layer 30, and reattach the other optical film 1 with the adhesive layer to the substrate 40 or the metal layer 30, which is the so-called reprocessing operation . The optical film 1 with the adhesive layer formed by the adhesive composition of the present invention is less prone to clouding, glue residue, etc. on the surface of the glass substrate or transparent electrode after peeling, and has excellent reworkability.

[4] Liquid crystal display device

The liquid crystal display device of the present invention includes the above-mentioned optical film 1 with an adhesive layer formed of the adhesive composition of the present invention, and more typically includes the above-mentioned optical laminate.

Therefore, the liquid crystal display device of the present invention has excellent durability.

The liquid crystal display device of the present invention can also be a touch input type liquid crystal display device with a touch panel function. The touch input type liquid crystal display device is provided with a touch input element including a liquid crystal cell and a backlight board. The structure of the touch panel can be a well-known type (for example, an out-cell type (out-cell type), an in-cell type (on-cell type, in-cell type), etc.), and the operation method of the touch panel can be a well-known type [For example, resistive film method, capacitance method (surface capacitance method, projection capacitance method), etc.]. The optical film 1 with an adhesive layer of the present invention can be arranged on the recognition side of the touch input element (liquid crystal cell), or on the backlight side, or on both sides. The driving method of the liquid crystal cell may be any previously known method such as TN method, VA method, IPS method, Multi-Domain method, and OCB method. Furthermore, in the liquid crystal display device of the present invention, the substrate 40 included in the optical laminate may be a substrate (typically a glass substrate) included in the above-mentioned liquid crystal cell.

[Example]

Hereinafter, examples and comparative examples are disclosed to explain the present invention more specifically, but the present invention is not limited by these examples. As long as there is no special statement below, it means that the used amount, content, and% are all based on weight.

<Production Example 1: Production of (meth)acrylic resin (A-1) for adhesive layer>

In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirrer, a solution obtained by mixing 81.8 parts of ethyl acetate with monomers of the composition shown in Table 1 (the values in Table 1 are parts by weight) was added. After replacing the air in the reaction vessel with nitrogen, the internal temperature was set to 60°C. Subsequently, the addition of azobis A solution of 0.12 parts of isobutyronitrile dissolved in 10 parts of ethyl acetate. After maintaining the same temperature for 1 hour, while maintaining the internal temperature at 54 to 56°C, ethyl acetate was continuously added to the reaction vessel at an addition rate of 17.3 parts/Hr so that the polymer concentration became approximately 35%. From the start of the addition of ethyl acetate to 12 hours after the internal temperature was maintained at 54 to 56°C, ethyl acetate was further added to adjust the polymer concentration to 20% to obtain (meth)acrylic resin (A -1) The ethyl acetate solution. The weight average molecular weight Mw of the obtained (meth)acrylic resin (A-1) was 1.39 million, and the ratio (Mw/Mn) of the weight average molecular weight Mw to the number average molecular weight Mn was 5.32.

<Production example 2-12: Production of (meth)acrylic resin (A-2 to 12) for adhesive layer>

Except that the composition of the monomers was set to the composition shown in Table 1, the rest was carried out in the same manner as in Production Example 1 to obtain an ethyl acetate solution of (meth)acrylic resins (A-2 to 12) (resin concentration: 20%) . The weight average molecular weight Mw of the obtained (meth)acrylic resins (A-2 to 12) was in the range of 1.3 million to 1.5 million, and Mw/Mn was in the range of 4 to 6.

In the above manufacturing example, the weight average molecular weight Mw and the number average molecular weight Mn are 4 "TSKgel XL" manufactured by TOSOH (stock) and 1 "Shodex GPC KF-802" manufactured by Showa Denko Corporation. A total of 5 columns are used as the columns and are connected in series in the GPC device, and tetrahydrofuran is used as the eluent. Under the conditions of a sample concentration of 5 mg/mL, a sample introduction amount of 100 μL, a temperature of 40°C, and a flow rate of 1 mL/min, Measured by standard polystyrene conversion. Get GPC The conditions for discharging the curve are also the same.

Glass transition temperature Tg uses SII Nano The differential scanning calorimeter (DSC) "EXSTAR DSC6000" manufactured by Technology Co., Ltd. measures under the conditions of a measurement temperature range of -80 to 50°C and a temperature rise rate of 10°C/min in a nitrogen atmosphere.

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

The abbreviations in the "monomer composition" column of Table 1 mean the following monomers.

BA: butyl acrylate (the glass transition temperature of the homopolymer: -54°C), MA: methyl acrylate (the glass transition temperature of the homopolymer: 10°C), HEA: 2-hydroxyethyl acrylate.

4HBA: 4-hydroxybutyl acrylate

5HPA: 5-hydroxypentyl acrylate

PEA: phenoxyethyl acrylate

PEA2: Phenoxydiethylene glycol acrylate

BMAA: Butoxy methacrylamide

AA: Acrylic

<Examples 1 to 12, Comparative Examples 1 to 9>

(1) Preparation of adhesive composition

In the ethyl acetate solution (resin concentration: 20%) of the (meth)acrylic resin obtained in the above production example, the amount (parts by weight) shown in Table 2 with respect to 100 parts of the solid content of the solution The coupling agent (B), the silane compound (C), and the ionic compound (D) are mixed, and ethyl acetate is added so that the solid content concentration becomes 14% to obtain an adhesive composition. The blending amount of each blending ingredient shown in Table 2 is set as the weight part of the active ingredient contained in the product used when the product contains a solvent or the like.

The details of each compounding component indicated by abbreviations in Table 2 are as follows.

(Crosslinking agent)

B-1: Ethyl acetate solution of trimethylolpropane adduct of toluene diisocyanate (solid content 75%), trade name "CORONATE L" obtained from TOSOH (Stock).

B-2: Ethyl acetate solution of trimethylolpropane adduct of xylene diisocyanate (solid content 75%), trade name "TAKENATE D-110N" obtained from Mitsui Chemicals Co., Ltd.

(Silane compound)

C-1: 1,6-bis(trimethoxysilyl)hexane, C-2: 1,8-bis(trimethoxysilyl)hexane, C-3: methyl/methoxy-containing Polysiloxane oligomer, trade name "X-40-9250", C-4: 1,3-bis(3'-trimethoxypropyl)urea obtained from Shin-Etsu Chemical Industry Co., Ltd.

(Ionic compound)

D-1: Bis(fluorosulfonyl)imide N-decylpyridinium, D-2: Bis(fluorosulfonyl)imide potassium, D-3: Bis(trifluoromethylsulfonyl)imide Lithium amide, D-4: N-decylpyridinium tetrakis(pentafluorophenyl)borate.

(2) Manufacturing of adhesive layer

Each adhesive composition prepared in (1) above was applied to a polyethylene terephthalate film that had been subjected to mold release treatment using an applicator so that the thickness after drying became 20 μm. The formed separation membrane [trade name "PLR-382051" obtained from LINTEC Co., Ltd.] has a release treatment surface, and is dried at 100°C for 1 minute to produce an adhesive layer (adhesive sheet).

(3) Manufacturing of optical film (P-1) with adhesive layer

A polyvinyl alcohol film with an average degree of polymerization of about 2400, a degree of saponification of 99.9 mol%, and a thickness of 60 μm [Kuraray Vinylon VF-PE#6000, a trade name made by Kuraray Co., Ltd.] was immersed in pure water at 37°C. Immerse in an aqueous solution containing iodine and potassium iodide (iodine/potassium iodide/water (weight ratio)=0.04/1.5/100) at 30°C. Subsequently, it was immersed in an aqueous solution containing potassium iodide and boric acid (potassium iodide/boric acid/water (weight ratio)=12/3.6/100) at 56.5°C. After washing the film with pure water at 10°C, it was dried at 85°C to obtain a polarizer with a thickness of about 23 μm in which iodine was adsorbed and aligned with polyvinyl alcohol. The stretching was mainly performed in the steps of iodine dyeing and boric acid treatment, and the total stretching magnification was 5.3 times.

A 25μm thick transparent protective film made of cellulose triacetate film [trade name "KC2UA" manufactured by Konica Minolta Co., Ltd.] is pasted on the surface through an adhesive made of an aqueous solution of polyvinyl alcohol resin. One side of the obtained polarizer. Next, a 23μm thick zero retardation film made of cyclic polyolefin resin [trade name "ZEONOR" manufactured by Japan ZEON Co., Ltd.] is passed through an adhesive made of an aqueous solution of polyvinyl alcohol resin. The above-mentioned polarizer was bonded to the surface on the opposite side to the cellulose triacetate film to produce a polarizing plate. Secondly, after corona discharge treatment is applied to the surface of the zero retardation film that is in contact with the polarizer on the opposite side to improve the adhesion, the adhesive made in (2) above is bonded by a laminating machine. After bonding the agent layer on the opposite side of the separation film (adhesive layer), it was aged for 7 days under the conditions of a temperature of 23° C. and a relative humidity of 65% to obtain an optical film (P-1) with an adhesive layer.

(4) Durability evaluation of optical film with adhesive layer

The optical film (P-1) with the adhesive layer produced in (3) above is cut into a size of 300mm×220mm with the extension axis direction of the polarizing plate as the long side, and the separation film is peeled off and exposed The adhesive layer is attached to the glass substrate or glass substrate with ITO (tin-doped indium oxide). The obtained glass substrate-attached test piece (optical film attached with the adhesive layer of the glass substrate) was pressurized in an autoclave at a temperature of 50°C and a pressure of 5kg/cm ² (490.3kPa) for 20 minutes . The glass substrate used the brand name "Eagle XG" of an alkali-free glass manufactured by Corning Corporation. In addition, as a glass substrate with ITO, a 30-nm ITO layer was formed on Corning Corporation's alkali-free glass [trade name "Eagle XG"] by ITO vapor deposition.

With respect to the obtained optical laminate, the following three types of durability tests were implemented.

[Durability test]

˙Heat resistance test (glass substrate) for 1000 hours under dry conditions at a temperature of 95℃, ˙Heat resistance test (glass with ITO) for 1000 hours under dry conditions at a temperature of 95℃, ˙Heat resistance test (glass substrate) for 1000 hours in an environment with a temperature of 60℃ and a relative humidity of 90%, ˙Hold for 30 minutes under the dry condition at a temperature of 85℃, and then set it as a cycle of keeping for 30 minutes under the dry condition at a temperature of -40℃, and repeat the heat shock (HS) test for 1000 cycles (glass substrate) .

Visually observe the optical laminate after each test, and visually observe whether the adhesive layer has any changes in appearance such as floating, peeling, and foaming. The durability was evaluated according to the following evaluation criteria. The results are shown in Table 3.

5: No appearance changes such as floating, peeling, foaming, etc. are observed at all, 4: Little appearance changes such as floating, peeling, foaming, etc. are observed, 3: Appearance changes such as floating, peeling, and foaming are slightly changed Obviously, 2: Appearance changes such as floating, peeling, and foaming are obvious, 1: Appearance changes such as floating, peeling, and foaming can be clearly observed.

(5) Adhesion evaluation of optical film with adhesive layer

The adhesive layer-attached optical film (P-1) prepared in (3) above was cut into a test piece with a size of 25 mm×150 mm. The separator was peeled from the test piece, and its adhesive surface was attached to the glass substrate. The obtained glass substrate-attached test piece (optical film attached with the adhesive layer of the glass substrate) was pressurized in an autoclave at a temperature of 50°C and a pressure of 5kg/cm ² (490.3kPa) for 20 minute. After storing for 24 hours in an environment with a temperature of 23° C. and a relative humidity of 50%, the optical film and the adhesive layer were simultaneously peeled from the test piece in the 180° direction at a speed of 300 mm/min. The average peel force during peeling was set as the adhesive force and shown in Table 3. When the adhesive force is 10N or less, it has excellent reworkability, and when it is 0.5N or more, it is not easy to peel off even when it is impacted from the end of the polarizing plate.

[Evaluation of ITO Corrosion of Optical Laminate]

A low resistivity meter [trade name "Loresta AX" manufactured by Mitsubishi Chemical Analytech Co., Ltd.] was used to measure the surface resistance of the ITO layer surface of the glass substrate with the ITO layer (the surface resistance value before the test). Next, cut the polarizing plate with the adhesive layer formed in the above (3) into a test piece with a size of 20mm×40mm. The sheet is attached to the ITO layer side of the glass substrate through the adhesive layer. The obtained optical laminate 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 environment at a temperature of 23°C and a relative humidity of 50%. The surface resistance (surface resistance value after the test) of the ITO layer after peeling was measured. The resistance change rate before and after the test was calculated according to the following formula, and the evaluation was performed based on the following criteria. The smaller the resistance change rate, the lower the corrosiveness of ITO. 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 of ITO Corrosion>

○: The resistance change rate is less than 50%, and it is an optical laminate with good ITO corrosivity.

×: 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 peeling off the separator of the obtained polarizing film with the adhesive layer, the surface resistance of the adhesive was measured using a surface resistance measuring device ["Hiresta-up MCP-HT450" (trade name) manufactured by Mitsubishi Chemical Corporation) value. It was implemented under the measurement conditions of an applied voltage of 250V 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 method for evaluating the gel fraction of the adhesive sheet of the present invention is disclosed. The larger the gel fraction, the more cross-linking reactions will proceed in the adhesive, which can be set as the target of the cross-link density. The gel fraction is measured in accordance with the following (1) to (4) The value.

(1) The adhesive sheet with an area of about 8cm×about 8cm is attached to a metal mesh of about 10cm×about 10cm made of SUS304 (the weight is set as Wm).

(2) Weigh the adhesive obtained in the above (1) and set its weight as Ws, and then fold it 4 times by wrapping the adhesive sheet and fix it with a stapler and weigh it Set its weight as Wb.

(3) Put the nets fixed by the stapler in the above (2) into a glass container, add 60 mL of ethyl acetate for immersion, and store the glass container at room temperature for 3 days.

(4) The net was taken out from the glass container, dried at 120°C for 24 hours, and then weighed. The weight was set to Wa, and the gel fraction was calculated based on the following formula.

Gel fraction (weight%)=[{Wa-(Wb-Ws)-Wm}/(Ws-Wm)]×100

1‧‧‧Optical film with adhesive layer

10‧‧‧Optical Film

20‧‧‧Adhesive layer

Claims (11)

An adhesive composition containing (meth)acrylic resin (A), crosslinking agent (B), and silane compound (C), wherein the aforementioned (meth)acrylic resin (A) contains: source From the structural unit of hydroxyl-containing (meth)acrylate represented by the following formula (a1),

In the formula, n represents an integer from 1 to 4, A ¹ represents a hydrogen atom or an alkyl group, and X ¹ represents an optionally substituted methylene group. When n is 2 or more, the aforementioned substituents may be the same or different; and The structural unit derived from the hydroxyl-containing (meth)acrylate represented by the following formula (a2),

In the formula, m represents an integer greater than ^{or equal to 5, A 2} represents a hydrogen atom or an alkyl group, and X ² represents a methylene group which may have a substituent. The aforementioned substituents may be the same or different; The total structural unit of the resin is 100 parts by weight, and the ratio of structural units derived from the hydroxyl-containing (meth)acrylate represented by formula (a1) is 1.5 to 4.5 parts by weight, derived from the hydroxyl-containing represented by formula (a2) The ratio of the structural units of the (meth)acrylate is 0.25 to 1.0 parts by weight; the aforementioned crosslinking agent (B) is a toluene diisocyanate compound and/or an adduct obtained by adding a polyol compound to a toluene diisocyanate compound . The adhesive composition according to claim 1, wherein the (meth)acrylic resin contains a structural unit derived from alkyl acrylate (a3), and the structural unit derived from alkyl acrylate (a3) It contains: structural units of alkyl acrylate (a3-1) whose glass transition temperature is less than 0°C derived from homopolymer; and alkyl acrylate whose glass transition temperature is above 0°C derived from homopolymer (a3-2) The structural unit. The adhesive composition described in item 2 of the scope of patent application, wherein the structural unit of alkyl acrylate (a3-1) whose glass transition temperature derived from homopolymer is less than 0°C is the same as that derived from homopolymer The ratio (weight ratio) between the structural units of alkyl acrylate (a3-2) whose glass transition temperature is above 0℃ is (a3-1)/(a3-2)=20/80 to 95/ 5. The adhesive composition according to any one of items 1 to 3 in the scope of the patent application, 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 adhesive composition according to any one of items 1 to 3 in the scope of the patent application, wherein the ratio of the crosslinking agent (B) is 0.01 to 100 parts by weight of the (meth)acrylic resin (A) 10 parts by weight. The adhesive composition according to any one of items 1 to 3 in the scope of patent application, wherein the silane compound (C) is a silane compound represented by the following formula (c1),

In the formula, B represents an alkanediyl group having 1 to 20 carbons or a divalent alicyclic hydrocarbon group having 3 to 20 carbons, and -CH ₂ -constituting the alkanediyl group and the alicyclic hydrocarbon group can be replaced with -O -Or-CO-, R ¹ represents an alkyl group having 1 to 5 carbons, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 5 carbons or a carbon number 1. To 5 alkoxy. The adhesive composition described in item 6 of the scope of patent application, wherein B of formula (c1) is an alkanediyl group having 1 to 10 carbons, R ¹ is an alkyl group having 1 to 5 carbons, and R ² , R ³ , R ⁴ , R ⁵ and R ⁶ are each independently an alkoxy group having 1 to 5 carbon atoms. The adhesive composition according to any one of items 1 to 3 in the scope of the patent application, wherein the ratio of the silane compound (C) to 100 parts by weight of the (meth)acrylic resin (A) is 0.01 to 10 Parts by weight. The adhesive composition according to any one of items 1 to 3 in the scope of the patent application, wherein the gel fraction of the adhesive formed by the adhesive composition is 50 to 95%. The adhesive composition according to any one of items 1 to 3 in the scope of patent application, wherein the adhesive layer formed by the aforementioned adhesive composition is attached to a glass substrate at a temperature of 23°C and a relative humidity of 50% The adhesive force of the aforementioned adhesive layer after 24 hours under the conditions of, is 0.5 to 10N/25mm at a peeling speed of 300mm/min. The adhesive composition described in any one of items 1 to 3 in the scope of the patent application is used to form an adhesive layer laminated on an optical film.

Images