KR20130110071A - Adhesive composition, adhesive and adhesive sheet - Google Patents

Abstract

PURPOSE: An adhesive composition does not need aging after forming an adhesive layer and has excellent adhesion with a polarizing plate without a saponification treatment. CONSTITUTION: An adhesive composition contains a (meth)acrylic acid ester polymer which includes nitrogen-containing monomers as a monomer unit and has a weight average molecular weight of 600,000-2,000,000; and contains an active energy ray-curable component. The nitrogen-containing monomer is a monomer with a tertiary amino group. The weight ratio of the active energy ray-curable component is 1-25 parts by weight to 100.0 parts by weight of the (meth)acrylic ester polymer. An adhesive sheet includes a substrate (13) and an adhesive layer (11). The adhesive layer consists of an adhesive formed of the adhesive composition.

Description

Adhesive composition, adhesive and adhesive sheet {ADHESIVE COMPOSITION, ADHESIVE AND ADHESIVE SHEET}

TECHNICAL FIELD This invention relates to an adhesive composition, an adhesive (material which hardened the adhesive composition), and an adhesive sheet, and especially relates to the adhesive composition, adhesive, and adhesive sheet which are suitable for optical members, such as a polarizing plate.

Recently, a liquid crystal display (LCD) is widely used as a display device, but a liquid crystal cell is used as an optical component constituting the liquid crystal display device. In general, the liquid crystal cell is arranged so that the alignment layers of the two transparent electrode substrates on which the alignment layer is formed are arranged at a predetermined interval by the spacers, and the periphery thereof is sealed to seal the periphery of the two transparent electrode substrates. The liquid crystal material is sandwiched in between. Usually, the polarizing plate is adhere | attached on the outer side of two transparent electrode substrates in a liquid crystal cell through an adhesive, respectively.

A polarizing plate generally consists of a polarizing film which has a 3-layered structure which bonded together an optically isotropic film, for example, a triacetyl cellulose (TAC) film, etc. on both surfaces of a polyvinyl alcohol-type polarizer, Furthermore, the single side | surface is the said transparent An adhesive layer is provided for the purpose of sticking to an electrode substrate etc., and is usually used as a polarizing plate with an adhesive.

In general, the pressure-sensitive adhesive layer is formed by adding a crosslinking agent to the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer and performing crosslinking treatment. However, in a crosslinking agent such as an isocyanate-based crosslinking agent or an epoxy-based crosslinking agent, the crosslinking is not completed after coating drying, and in order to completely crosslink, aging of about 3 days to 1 week is usually required after that.

Before affixing a polarizing plate with an adhesive to a liquid crystal cell, various processing processes, such as a punching process and a slit processing, are performed. Here, if such aging is not performed sufficiently, the adhesive adheres to the cutting knife, the adhesive is pushed out from the cut surface of the cut member, and the upper and lower members adhere to each other when polymerizing the member. Is generated. On the other hand, when the heating treatment is performed to promote aging, the dimensional change of the polarizing plate or the retardation plate is generated, and optical distortion is likely to occur.

As the aging treatment takes a long time as described above, productivity was significantly inhibited. In other words, after the optical member with pressure-sensitive adhesive is manufactured, it is very advantageous in terms of productivity that the above processing can be quickly performed without an aging treatment.

In order to make an aging period unnecessary, the adhesive which hardens the said adhesive composition by ultraviolet-ray using the adhesive composition containing an acrylic polymer and an ultraviolet curable resin without containing a thermal crosslinking agent is proposed (patent document 1, 2). The pressure-sensitive adhesive described in these documents was to adhere the polarizing plate and the glass substrate with good durability, to be excellent in light leakage prevention property, and to also have a rework property to the glass substrate.

[Patent Document 1] Japanese Patent No. 3921017 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-190302

Conventionally, in the polarizing plate, after saponification of the surface, it was common to laminate an adhesive layer on the surface. However, in recent years, it has been strongly expected to omit the saponification process on the surface of the polarizing plate due to the sharp price reduction of the liquid crystal display device.

Since the adhesiveness of a polarizing plate and an adhesive layer falls extremely in the polarizing plate which abbreviate | omitted the sensitizing process, durability often becomes a problem. Especially in the adhesive which does not require the aging period described in the said document, this problem is remarkable.

This invention is made | formed in view of such a situation, and an object of this invention is to provide the adhesive composition, an adhesive, and an adhesive sheet which are not required for aging after formation of an adhesive layer, and are excellent also in adhesiveness with a base material, especially the polarizing plate which does not perform a saponification process.

In order to achieve the above object, firstly, the present invention provides a (meth) acrylic acid ester polymer (A) having a weight average molecular weight of 600,000 to 2 million and containing a monomer having a nitrogen atom as a monomer unit constituting the polymer. And an active energy ray curable component (B). The adhesive composition characterized by the above-mentioned (invention 1) is provided.

In the adhesive composition according to the invention (Invention 1), since the curing of the pressure-sensitive adhesive is substantially completed immediately after the pressure-sensitive adhesive layer is formed by irradiation of active energy rays, aging is unnecessary, and the physical properties of the pressure-sensitive adhesive immediately after the pressure-sensitive adhesive layer is formed. Is stable. The adhesive which hardened the adhesive composition which concerns on the said invention (invention 1) is a polarizing plate which does not perform a base material, especially the sensitization process by making the (meth) acrylic acid ester polymer (A) contain the monomer which has a nitrogen atom as a structural monomer unit, The adhesion is greatly improved, and excellent durability is exhibited.

In the said invention (invention 1), it is preferable that the monomer which has the said nitrogen atom is a monomer which has a tertiary amino group (invention 2).

In the said invention (Invention 2), it is preferable that the monomer which has the said tertiary amino group is at least 1 sort (s) chosen from N, N-dimethylaminoethyl acrylate, N, and N-dimethylaminoethyl methacrylate (Invention 3).

In the said invention (invention 1-3), it is preferable that the said (meth) acrylic acid ester polymer (A) contains 0.01-5.0 weight% of monomers which have the said nitrogen atom as a monomer unit which comprises the said polymer (invention) 4).

In the said invention (Invention 1-4), it is preferable that the ratio of the said active energy ray curable component (B) with respect to 100 weight part of said (meth) acrylic acid ester polymers (A) is 1-25 weight part (invention 5) .

In the said invention (invention 1-5), it is preferable that the said adhesive composition further contains a photoinitiator (C) (invention 6).

In the said invention (invention 6), it is preferable that content of the said photoinitiator (C) is 2-15 weight part with respect to 100 weight part of said active energy ray curable components (B) (invention 7).

In the adhesive composition which concerns on the said invention (invention 1-7), it is preferable that the said active energy ray curable component (B) is at least 1 sort (s) chosen from a polyfunctional (meth) acrylate monomer and a polyfunctional (meth) acrylate oligomer. Or tris ((meth) acryloxyethyl) isocyanurate.

Moreover, it is preferable that the adhesive composition which concerns on the said invention (Invention 1-7) further contains a silane coupling agent (D).

Secondly, the present invention provides a pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition (Invention 1 to 7) by irradiation of an active energy ray (Invention 8).

It is preferable that the adhesive according to the said invention (invention 8) is 0.01-0.8 Mpa of storage elastic modulus (G ') in 23 degreeC (invention 9).

It is preferable that the adhesive of the said invention (invention 8, 9) is 10-2000mJ / cm <^2> in the irradiation amount of the said active energy ray.

Thirdly, the present invention provides a pressure-sensitive adhesive sheet comprising a base material and an pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesives (Invention 8, 9) (Invention 10).

In the said invention (invention 10), it is preferable that the said base material is an optical member (invention 11).

In the invention (invention 11), the optical member is preferably a polarizing plate (invention 12).

Fourthly, the present invention provides a pressure-sensitive adhesive sheet having two release sheets and a pressure-sensitive adhesive layer sandwiched on the release sheet so as to contact the release surfaces of the two release sheets, wherein the pressure-sensitive adhesive layer is the pressure-sensitive adhesive (invention 8, 9). It provides the adhesive sheet which consists of (Invention 13).

In the adhesive composition which concerns on this invention, since hardening of an adhesive is substantially completed immediately after formation of an adhesive layer by irradiation of an active energy ray, aging is unnecessary and the physical property of an adhesive is stabilized immediately after formation of an adhesive layer. Thereby, the shipment of the member with the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive and the next step of processing can be performed quickly, which is very advantageous in terms of intermediate material inventory burden and productivity.

Moreover, the adhesive which hardened the adhesive composition which concerns on this invention contains the monomer which a (meth) acrylic acid ester polymer (A) has a nitrogen atom as a structural monomer unit, and it is adhesiveness with a base material, especially the polarizing plate which has not performed the saponification process. This greatly improves and shows excellent durability.

1 is a cross-sectional view of an adhesive sheet according to a first embodiment of the present invention.
2 is a cross-sectional view of an adhesive sheet according to a second embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described.

[Adhesive composition]

The adhesive composition (henceforth "adhesive composition (P)") which concerns on this embodiment is a weight average molecular weight (Mw) 600,000-2 million, and is a monomer unit which comprises a nitrogen atom as a monomer unit which comprises a polymer ( (Meth) acrylic acid ester polymer (A) containing a nitrogen atom containing monomer (hereinafter, may only be called "polymer (A)"), and an active energy ray curable component (B), Preferably Contains a photoinitiator (C) or a silane coupling agent (D) further. In addition, in this specification, a (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. Other similar terms are the same. The term &quot; polymer &quot; also includes the concept of &quot; copolymer &quot;.

Since the hardening (crosslinking) reaction does not advance before the said adhesive composition (P) irradiates an active energy ray, it is easy to handle and is excellent in coatability. When the active energy ray is irradiated to the adhesive composition (P), the plurality of active energy ray curable components (B) are bonded to each other to form a three-dimensional network structure. It is estimated that a plurality of high molecular weight polymers (A) are inserted into the three-dimensional network structure and constrained so that a pseudo crosslinked structure is formed between the high molecular weight polymers (A). Is called). Since hardening of such an adhesive is substantially completed immediately after irradiation of an active energy ray, the aging after formation of an adhesive layer is unnecessary, and the physical properties, such as the adhesive force of an adhesive, are stabilized from immediately after formation of an adhesive layer. Furthermore, the adhesive obtained has the adhesiveness with a base material, especially the polarizing plate which did not perform the saponification process by the action by the polarity, because the (meth) acrylic acid ester polymer (A) contains a nitrogen atom containing monomer as a structural monomer unit. It is greatly improved and shows excellent durability with the above structure X.

As a nitrogen atom containing monomer which a (meth) acrylic acid ester polymer (A) contains as a structural monomer unit, the monomer which has nitrogen containing heterocycles, such as the monomer which has an amino group, the monomer which has an amide group, and a pyridinium ring, etc. are mentioned. . Especially, the monomer which has an amino group is preferable, and it is especially preferable that it is a monomer which has a tertiary amino group. As a monomer which has a tertiary amino group, (meth) acrylic-acid N, N-dimethylaminoethyl, (meth) acrylic-acid N, N-dimethylaminopropyl, etc. are mentioned, Especially, Nacrylate and N-dimethylamino Preference is given to ethyl and methacrylic acid N, N-dimethylaminoethyl. This nitrogen atom containing monomer exhibits the effect which improves especially adhesiveness with a polarizing plate (especially the polarizing plate which is not subjected to a saponification process). These may be used independently and may be used in combination of 2 or more type.

In order to express adhesiveness, it is preferable that the (meth) acrylic acid ester polymer (A) contains the C1-C20 (meth) acrylic-acid alkylester as a monomer unit which comprises the said polymer. Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, N-butyl (meth) acrylate, and (meth) acrylic acid. N-pentyl, (meth) acrylic acid N-hexyl, (meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid isooctyl, (meth) acrylic acid N-decyl, (meth) acrylic acid N-dodecyl, (meth) acrylic acid in advance Steel, palmity (meth) acrylate, stearyl (meth) acrylate, and the like. Especially, from a viewpoint of improving adhesiveness further, the (meth) acrylic acid ester of 4-8 carbon atoms of an alkyl group is preferable, and (meth) acrylic-acid N-butyl and (meth) acrylic-acid 2-ethylhexyl are especially preferable. In addition, these may be used independently and may be used in combination of 2 or more type.

The (meth) acrylic acid ester polymer (A) constitutes another monomer as appropriate, in addition to the nitrogen atom-containing monomer and the alkyl group having 1 to 20 carbon atoms of the (meth) acrylic acid alkyl ester described above, without impairing the effects of the present invention. Can be in units.

The other monomer may be a monomer having a reactive functional group (reactive functional group-containing monomer) or a nonreactive monomer. As a reactive functional group containing monomer, the monomer (hydroxyl group containing monomer) which has a hydroxyl group in a molecule | numerator, the monomer (carboxyl group containing monomer) which has a carboxyl group in a molecule | numerator, etc. are mentioned preferably, One type individually or in combination of 2 or more types Can be used.

As a hydroxyl-containing monomer, For example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, ( (Meth) acrylic-acid hydroxyalkyl esters, such as 3-hydroxybutyl methacrylate and 4-hydroxybutyl (meth) acrylate, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

As a carboxyl group-containing monomer, ethylenic unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, a citraconic acid, are mentioned, for example. These may be used independently and may be used in combination of 2 or more type.

As a non-reactive monomer, (meth) which has aliphatic rings, such as (meth) acrylic-acid alkoxyalkyl esters, such as (meth) acrylic-acid methoxyethyl and (meth) acrylic-acid ethoxyethyl, and (meth) acrylic-acid cyclohexyl, for example. (Meth) acrylic acid ester which has aromatic rings, such as acrylic ester and phenyl (meth) acrylate, vinyl acetate, styrene, etc. are mentioned. These may be used independently and may be used in combination of 2 or more type.

It is preferable that (meth) acrylic acid ester polymer (A) contains 0.01-5.0 weight% of said nitrogen atom containing monomers as a monomer unit which comprises the said polymer, and it is especially preferable to contain 0.05-3.5 weight%, Furthermore, it is preferable to contain 0.1-2.0 weight%. By containing a nitrogen atom containing monomer in the said range, the adhesive obtained is excellent in adhesiveness with a base material, and durability also improves. When content of a nitrogen atom containing monomer is less than 0.01 weight%, such an effect may not fully be acquired. On the other hand, when content of a nitrogen atom containing monomer exceeds 5.0 weight%, the adhesive force of the adhesive obtained, further durability may fall, or peelability and rework property may be inferior.

The (meth) acrylic acid ester polymer (A) is a monomer unit constituting the polymer, and contains 50 to 99.99% by weight of the alkyl group having 1 to 20 carbon atoms of the alkyl group and the aforementioned non-reactive monomer. It is preferable to contain 80-99.00 weight% especially, and it is preferable to contain 93-98 weight% further. When content of the sum total of the said (meth) acrylic-acid alkylester and the said non-reactive monomer is less than 50 weight%, there exists a possibility that adhesive force may become excessively low. On the other hand, when content of the said (meth) acrylic-acid alkylester exceeds 99.99 weight%, the compounding ratio of the said nitrogen atom containing monomer may be insufficient.

In addition, when using together the C1-C20 (meth) acrylic-acid alkylester and the said non-reactive monomer of an alkyl group, the ratio which the C1-C20 (meth) acrylic-acid alkylester of both alkyl groups occupies occupies for adhesive force It is preferable that it is 50 weight% or more from a viewpoint of improving this, It is especially preferable that it is 60 weight% or more, It is more preferable that it is 70 weight% or more. In addition, as an upper limit of the said compounding ratio of both, 100 weight% of the C1-C20 (meth) acrylic-acid alkylester of an alkyl group may be sufficient.

It is preferable that (meth) acrylic acid ester polymer (A) contains 0.01-10 weight% of said reactive functional group containing monomers as a monomer unit which comprises the said polymer, It is preferable to contain especially 0.05-8.0 weight%, Furthermore, it is preferable to contain 0.1-5.0 weight%. By containing a reactive functional group containing monomer in the said range, the said structure X can be formed efficiently. Moreover, when adhesive composition (P) contains a silane coupling agent (D), the adhesiveness with respect to the glass substrate of the adhesive obtained can be improved by reaction with the said silane coupling agent (D).

The polymerization method of the (meth) acrylic acid ester polymer (A) may be a random copolymer or a block copolymer.

The weight average molecular weight of (meth) acrylic acid ester polymer (A) is 600,000-2 million, Preferably it is 800,000-1,800,000, Especially preferably, it is 1 million-1,500,000. In addition, the weight average molecular weight in this specification is a value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

If the weight average molecular weight of a (meth) acrylic acid ester polymer (A) is less than 600,000, there exists a possibility that the adhesive obtained may be inferior in durability and rework property. When the weight average molecular weight of the (meth) acrylic acid ester polymer (A) exceeds 2 million, compatibility with the active energy ray-curable component (B) and the like deteriorates, formation of structure X becomes insufficient, and durability decreases. There is.

In addition, in an adhesive composition (P), (meth) acrylic acid ester polymer (A) may be used individually by 1 type, and may be used in combination of 2 or more type. Moreover, the adhesive composition (P) may further contain the (meth) acrylic acid ester polymer (A ') which does not contain a nitrogen atom containing monomer as a structural monomer unit. As such (meth) acrylic acid ester polymer (A '), the C1-C20 (meth) acrylic-acid alkylester of an alkyl group, the reactive functional group containing monomer used as desired, and the other used as desired, for example And copolymers with monomers.

In addition, when using the said polymer (A) and polymer (A ') together, the kind of reactive functional group containing monomer which is a structural unit of those polymers differs, for example as hydroxyl group containing monomer and carboxyl group containing monomer, respectively. It is desirable to. It is because it becomes possible to distinguish by design from the polymer which acts with a silane coupling agent (D), and the polymer for providing antistatic property etc. by this.

It is preferable that the compounding ratio of the (meth) acrylic acid ester polymer (A ') with respect to 100 weight part of (meth) acrylic acid ester polymers (A) is 50 weight part or less, and it is especially preferable that it is 30 weight part or less.

The active energy ray-curable component (B) is not particularly limited as long as it is a component that does not interfere with the effects of the present invention and is cured by irradiation of active energy rays. It is preferable that this active-energy-ray-curable component (B) is at least 1 sort (s) chosen from a polyfunctional (meth) acrylate monomer and a polyfunctional (meth) acrylate oligomer, Especially, (meth) acrylic acid ester polymer (A) It is preferable that it is a polyfunctional (meth) acrylate monomer excellent in compatibility with these.

As a polyfunctional (meth) acrylate monomer, For example, 1, 4- butanediol di (meth) acrylate, 1, 6- hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene Glycoldi (meth) acrylate, neopentylglycol adipate di (meth) acrylate, hydroxypivarine neopentylglycoldi (meth) acrylate, dicyclopentanyldi (meth) acrylate, caplactone-modified dicyclopentanyl Di (meth) acrylate, ethylene oxide modified phosphate di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane tri (meth) acrylic Latent, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimmet Thiolol propane tri (meth) acrylate, tris ((meth) acryloxyethyl) isocyanurate, propionic acid modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, caproltone modified Dipentaerythritol hexa (meth) acrylate etc. are mentioned, Especially, tris ((meth) acryloxyethyl) isocyanurate is preferable and tris (acryloxyethyl) isocyanurate is especially preferable. These may be used independently and may be used in combination of 2 or more type.

Examples of the polyfunctional (meth) acrylate oligomer include polyester acrylate oligomers, epoxy acrylate oligomers, urethane acrylate oligomers, polyether acrylate oligomers, polybutadiene acrylate oligomers, and silicone acrylates. A system oligomer etc. are mentioned.

A polyester acrylate oligomer is esterified by (meth) acrylic acid, or the hydroxyl group of the polyester oligomer which has a hydroxyl group in the sock end obtained by condensation of polyhydric carboxylic acid and a polyhydric alcohol, for example, The hydroxyl group of the terminal of the oligomer obtained by adding an alkylene oxide can be obtained by esterifying with (meth) acrylic acid.

An epoxy acrylate oligomer can be obtained by, for example, reacting and esterifying (meth) acrylic acid to an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or a novolak type epoxy resin. Moreover, you may use the carboxyl-modified epoxyacrylate oligomer which modified | denatured the epoxy acrylate oligomer partially with the dibasic carboxylic anhydride compound.

A urethane acrylate oligomer can be obtained by esterifying the polyurethane oligomer obtained by reaction of a polyether polyol, polyester polyol, and polyisocyanate, for example with (meth) acrylic acid.

A polyether acrylate oligomer can be obtained by esterifying the hydroxyl group of a polyether polyol with (meth) acrylic acid.

Said polyfunctional (meth) acrylate monomer and polyfunctional (meth) acrylate oligomer can be used individually by 1 type or in combination of 2 or more types, respectively. Moreover, you may use combining the polyfunctional (meth) acrylate monomer and the polyfunctional (meth) acrylate oligomer.

In addition, in an adhesive composition (P), an active energy ray curable component (B) may be used individually by 1 type, and may be used in combination of 2 or more type.

The blending ratio of the active energy ray-curable component (B) to 100 parts by weight of the (meth) acrylic acid ester polymer (A) is preferably 1 to 25 parts by weight, particularly preferably 2 to 20 parts by weight, further 5 to It is preferable that it is 10 weight part.

The adhesive obtained from the adhesive composition (P) containing a (meth) acrylic acid ester polymer (A) and an active energy ray curable component (B) in the said ratio is estimated to form the said structure X favorably.

Here, when using an ultraviolet-ray as an active energy ray irradiated to an adhesive composition (P), it is preferable that an adhesive composition (P) contains a photoinitiator (C) further. By containing a photoinitiator (C) in this way, an active energy ray curable component (B) can be hardened efficiently, and also the polymerization hardening time and the irradiation amount of an active energy ray can be reduced.

As such a photoinitiator (C), specifically, benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzoin benzoic acid, benzoin benzoic acid Methyl, benzoin dimethyl ketal, 2, 4-diethyl thioxane, 1-hydroxycyclohexylphenyl ketone, bendyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutylnitrile, benzyl, dibenzyl, di Acetyl, β-chloroanthraquinone, (2, 4, 6-trimethylbendyldiphenyl) phosphine oxide, 2-benzothiazole-N, N-diethyldithiocarbamate and the like. These may be used independently and may be used in combination of 2 or more type.

It is preferable that a photoinitiator (C) is used in the quantity of 2-15 weight part, especially 5-12 weight part with respect to 100 weight part of active energy ray curable components (B).

Adhesive composition (P), Preferably, it further contains a silane coupling agent (D). When this silane coupling agent (D) is contained, the adhesiveness to the glass substrate of the adhesive obtained can be improved, and as a result, durability improves more. For example, when a (meth) acrylic acid ester polymer (A) has a reactive functional group containing monomer as a structural unit, the organic reactive group of a silane coupling agent (D), etc., and the reactive functional group of a (meth) acrylic acid ester polymer (A) work | functions. On the other hand, the alkoxysilyl group and the like of the silane coupling agent (D) act on the surface of adherend such as a glass substrate. For this reason, when bonding a polarizing plate, for example to a liquid crystal glass cell etc., adhesiveness between an adhesive and a liquid crystal glass cell becomes more favorable.

As the silane coupling agent (D), an organosilicon compound having at least one alkoxysilyl group in its molecule is suitable for having good compatibility with the pressure-sensitive adhesive component and having a light transmittance, for example, a substantially transparent one. It is preferable that it is 0.01-1.0 weight part with respect to 100 weight part of (meth) acrylic acid ester polymers (A), and, as for the compounding quantity of such a silane coupling agent (D), it is especially preferable that it is 0.05-0.5 weight part.

Specific examples of the silane coupling agent (D) include polymerizable unsaturated group-containing silicon compounds such as vinyltrimethoxysilane, vinyltriethoxysilane, and methacryloxypropyltrimethoxysilane, and 3-glycidoxypropyltrimethoxysilane Silicon compounds having an epoxy structure such as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimeth Amino group-containing silicon compounds such as oxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, thiol group-containing silicon compounds such as 3-mercaptopropyltrimethoxysilane, and 3-chloropropyltrime Halogenated alkyl group-containing silicon compounds such as oxysilane, isocyanate group-containing silane compounds such as 3-isocyanatepropyltriethoxysilane, hydrolyzates of silane compounds, tetraalkoxysilanes such as the silane compounds and tetraethoxysilane, Balls and the like can be hydrolyzed. These may be used individually by 1 type and may be used in combination of 2 or more type.

It is preferable that adhesive composition (P) does not contain the heat crosslinking crosslinking agent which needs aging after formation of an adhesive layer, for example, an isocyanate crosslinking agent and an epoxy crosslinking agent. On the other hand, it is preferable to contain the crosslinking agent which does not require aging after formation of an adhesive layer, for example, an aziridine system crosslinking agent.

To the adhesive composition (P), various additives normally used for acrylic adhesives, for example, tackifiers, antistatic agents, antioxidants, ultraviolet absorbers, light stabilizers, softeners, fillers, refractive index adjusters, and the like can be added as desired. have.

Here, usually, when an adhesive composition contains an antistatic agent, the adhesive sheet obtained often becomes inadequate in durability. However, even when the adhesive composition (P) contains an antistatic agent, the adhesive sheet obtained by using the adhesive composition (P) can exhibit excellent durability with respect to the glass substrate.

In addition, as an antistatic agent, if it is a well-known thing, it will not be specifically limited and can be used. In view of the most preferable compatibility with the other components of the adhesive composition (P), as the cationic species, any of lithium, potassium, amine and pyridinium is preferable, and as the anionic species, bisperfluoroalkylsulfonyl is Any salt of mead, bisperfluorosulfonylimide and hexafluorophosphate is preferred. Specifically, 1-butyl-4-methylpyridinium hexafluoro phosphate etc. are mentioned preferably.

[Process for producing adhesive composition]

Adhesive composition (P) manufactures a (meth) acrylic acid ester polymer (A), mixes the obtained (meth) acrylic acid ester polymer (A) and an active energy ray curable component (B), and if desired, It can manufacture by adding a photoinitiator (C), a silane coupling agent (D), etc. in a step.

The (meth) acrylic acid ester polymer (A) can be manufactured by a normal radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) can be performed by a solution polymerization method or the like using a polymerization initiator as desired. As a polymerization solvent, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone etc. are mentioned, for example, You may use two or more types together.

As a polymerization initiator, an azo compound, an organic peroxide, etc. are mentioned, You may use two or more types together. As an azo type compound, 2, 2'- azobisisobutyronitrile, 2, 2'- azobis (2-methylbutyronitrile), 1, 1'- azobis (cyclohexane 1-carbo, for example) Nitrile, 2, 2'-azobis (2, 4-dimethylvaleronitrile), 2, 2'-azobis (2, 4-dimethyl-4-methoxyvaleronitrile), dimethyl 2, 2'-azo Bis (2-methylpropionate), 4, 4'-azobis (4-cyanobareric acid), 2, 2'-azobis (2-hydroxymethylpropionitrile), 2, 2'-azo Bis [2- (2-imidazolin-2-yl) propane] and the like.

Examples of the organic peroxide include benzoyl peroxide, t-butylperbenzoate, cumene hydroxide peroxide, diisopropylperoxydicarbonate, di-n-propylperoxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate , t-butyl peroxy neodecanoate, t-butyl peroxy vivarate, (3, 5, 5- (trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

In addition, in the said superposition | polymerization process, the weight average molecular weight of the polymer obtained can be adjusted by mix | blending chain transfer agents, such as 2-mercaptoethanol.

When the (meth) acrylic acid ester polymer (A) is obtained, the solution of the polymer (A) and the solution of an active energy ray curable component (B) are mixed, and a diluting solvent is added as needed. Then, the adhesive composition (coating solution) diluted with the solvent is obtained by adding a photoinitiator (C), a silane coupling agent (D), etc. as needed, and mixing sufficiently.

As a diluting solvent for diluting an adhesive composition and making it a coating solution, For example, aliphatic hydrocarbons, such as hexane, heptane, and cyclohexane, aromatic hydrocarbons, such as toluene and xylene, halogenated hydrocarbons, such as methylene chloride and ethylene chloride, methanol, ethanol Alcohols such as propanol, butanol and 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone and cyclohexanone, esters such as ethyl acetate and butyl acetate, and ethyl cell Cellosolve solvents, such as a solvent, etc. can be used.

The concentration and viscosity of the coating solution thus produced are not particularly limited and may be suitably selected in accordance with the circumstances as long as they are in a coating-enabling range. For example, it dilutes so that the density | concentration of an adhesive composition may be 10-40 weight%. On the other hand, when obtaining a coating solution, addition of a dilution solvent etc. is not a requirement, and if it is a viscosity etc. which an adhesive composition can coat, it is not necessary to add a dilution solvent. In this case, an adhesive composition turns into a coating solution as it is.

〔adhesive〕

The adhesive according to the present embodiment can be preferably obtained by applying the adhesive composition (P) to a desired object and drying it, and then curing the adhesive composition (P) by irradiation with an active energy ray.

Although drying of adhesive composition P may be performed by air drying, it is usually performed by heat processing (preferably hot air drying). When heat-processing, it is preferable that heating temperature is 50-150 degreeC, and it is especially preferable that it is 70-120 degreeC. The heating time is preferably 10 seconds to 10 minutes, more preferably 50 seconds to 2 minutes.

As an active energy ray, an ultraviolet-ray, an electron beam, etc. can be used normally. Although the irradiation amount of an active energy ray changes with kinds of energy rays, 50-1000mJ / cm <^2> is preferable as a light quantity, for example, in the case of an ultraviolet-ray, Especially 100-500mJ / cm <^2> is preferable. In the case of an electron beam, about 10-1000 krad is preferable.

By irradiation of the said active energy ray, some active energy ray curable component (B) combines with each other, and forms a three-dimensional network structure, The some (meth) acrylic acid ester polymer (A) is inserted in the three-dimensional network structure, It is assumed that the structure X is formed. At this time, since hardening of the adhesive composition (P) is performed quickly, there is no need of aging, and physical properties, such as adhesive force of the adhesive obtained, are stabilized from an initial stage. Thereby, the shipment of the member with the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive and the subsequent process addition can be performed quickly, which is very advantageous in terms of inventory burden and productivity of the intermediate material.

Moreover, the adhesive which concerns on this embodiment improves adhesiveness with a base material, especially the polarizing plate which has not been saponified significantly by the (meth) acrylic acid ester polymer (A) containing a nitrogen atom containing monomer as a structural monomer unit, In addition to the X structure, it has excellent durability. For example, even when placed at a high temperature of 80 ° C. and a high temperature, high humidity of 60 ° C. and 90% RH for 200 hours or when a heat shock of 30 ° C. to 35 ° C. to 70 ° C. (30 minutes, 200 cycles) is applied, Generation of bubbles or the like is prevented and suppressed.

The gel fraction of the pressure-sensitive adhesive according to the present embodiment immediately after the pressure-sensitive adhesive layer formation (in consideration of the time lag until the measurement, "just after the pressure-sensitive adhesive layer formation '' means within about half a day from active energy ray irradiation.) When the gel fraction after storing for 7 days in G1 and the pressure-sensitive adhesive layer formation at 23 ° C., 50% RH for 7 days, the following formula

Gel fraction variation (%) = | (G2-G1) / G2 | × 100

It is preferable that it is within 5%, and, as for the gel fraction variation rate computed from this, it is especially preferable that it is within 4.5%. The measurement method of a gel fraction is as showing to the test example mentioned later. As described above, that the gel fraction variation rate is within 5% indicates that the curing of the adhesive is substantially completed immediately after the formation of the adhesive layer.

It is preferable that it is 30 to 90%, respectively, and, as for the gel fraction G1 immediately after adhesive layer formation, and the said gel fraction G2 after 7 days storage, it is especially preferable that it is 50 to 80%. If the gel fraction is less than 30%, the cohesive force of the pressure-sensitive adhesive may be insufficient, and durability and reworkability may be lowered. Moreover, when gel fraction exceeds 90%, adhesive force may become excessively low and durability may fall.

It is preferable that the adhesive force which concerns on this embodiment is the difference of the adhesive force immediately after adhesive layer formation, and the adhesive force after 7 days storage in the environment of 23 degreeC and 50% RH from adhesive layer formation is less than +/- 3.0 N / 25mm, In particular, it is preferable to be within ± 2.5 N / 25 mm, and more preferably, within ± 2.0 N / 25 mm. On the other hand, the adhesive force here means 180 degree pull-out adhesive force (peel rate 300mm / min) based on JISZ0237, and affixes on a to-be-adhered body, pressurizes at 0.5 MPa and 50 degreeC for 20 minutes, and is 23 degreeC and 50 degree. It shall be measured after leaving for 24 hours under the condition of% RH. As described above, when the adhesive force difference is within ± 3.0 N / 25 mm, stable adhesive force can be exhibited from immediately after the pressure-sensitive adhesive layer is formed.

Moreover, even if the adhesive force of the adhesive which concerns on this embodiment is all in the case immediately after adhesive layer formation and after 7 days storage, it is preferable that adhesive force with respect to an alkali free glass is 0.1-50 N / 25mm, for example using a polarizing plate as a base material. In particular, it is preferable that it is 0.5-30 N / 25mm. By the adhesive force being in the said range, it can be set as the adhesive sheet which is excellent also in rework property while preventing lifting, peeling, etc. from a glass substrate.

It is preferable that the storage elastic modulus (G ') at 23 degrees C of the adhesive which concerns on this embodiment is 0.01-0.8 Mpa, It is especially preferable that it is 0.05-0.6 Mpa, Furthermore, it is preferable that it is 0.07-0.1 Mpa. When the storage modulus G 'is within the above range, the desired substrate adhesion and cohesion force can be obtained, and when applied to an optical member such as a polarizing plate, it can be applied at an interface with an optical member or an interface with a glass substrate under a durable environment. Lifting, peeling, etc. can be prevented effectively. In addition, the storage elastic modulus in this specification is made into the value measured at 1 Hz using a viscoelasticity measuring apparatus (in the test example, using DYNAMIC ANALYZER RDA II by Rheometrics).

It is preferable that the haze value (value measured according to JIS K7105) of the adhesive which concerns on this embodiment is 1.0% or less, It is especially preferable that it is 0.7% or less, Furthermore, it is preferable that it is 0.5% or less. If the haze value is 1.0% or less, the transparency is very high, and it is suitable for optical use.

The adhesive according to the present embodiment can be suitably used for an optical member, particularly for a polarizing plate, and for example, adhesion or polarizing plate (polarizing film) between optical members such as a polarizing plate (polarizing film) and a retardation plate (retardation film). ) And retardation film (retardation film) and glass substrates.

[Adhesion sheet]

As shown in FIG. 1, the adhesive sheet 1A which concerns on 1st Embodiment has the adhesive sheet 11 laminated | stacked on the peeling sheet 12 and the peeling surface of the peeling sheet 12 in order from the bottom. And the base material 13 laminated on the pressure-sensitive adhesive layer 11.

In addition, as shown in FIG. 2, the adhesive sheet 1B which concerns on 2nd Embodiment is made to contact the peeling surface of two peeling sheets 12a and 12b and those two peeling sheets 12a and 12b. It consists of the adhesive layer 11 clamped by the said two peeling sheets 12a and 12b. In addition, the peeling surface of the peeling sheet in this specification means the surface which has peelability in a peeling sheet, and includes both the surface which performed peeling process and the surface which shows peelability, even without peeling process.

Also in any adhesive sheet 1A, 1B, the adhesive layer 11 becomes an adhesive which hardens the adhesive composition mentioned above.

Although the thickness of the adhesive layer 11 is suitably determined according to the purpose of use of the adhesive sheets 1A and 1B, it is usually 5-100 micrometers, Preferably it is the range of 10-60 micrometers, For example, for optical members, especially a polarizing plate When using as an adhesive layer, it is 10-50 micrometers, It is preferable that it is 10-30 micrometers especially.

There is no restriction | limiting in particular as the base material 13, Any thing used as a base material sheet of a normal adhesive sheet can be used. For example, woven or nonwoven fabric using fibers such as rayon, acrylic, polyester, etc. in addition to the desired optical member; Synthetic paper; Paper such as quality paper, glassine paper, impregnated paper and coated paper; Metal foils such as aluminum and copper; Foams such as urethane foams and polyethylene foams; Polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyurethane films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose, polyvinyl chloride films, polyvinylidene chloride films, poly Plastic films such as vinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, norbornene-based resin films, and cycloolefin resin films; These 2 or more types of laminated bodies etc. are mentioned. The plastic film may be uniaxially extended or biaxially extended.

As the optical member, for example, a polarizing plate (polarizing film), a polarizer, a retardation plate (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, a semi-transmissive reflective film, etc. Can be mentioned. As a polarizing plate, Preferably, what bonded together the triacetyl cellulose (TAC) film on both surfaces of a polyvinyl alcohol-type polarizer is used. The adhesive layer 11 which concerns on this embodiment shows the outstanding adhesiveness with respect to a polarizing plate also in the said base material, and especially shows the outstanding adhesiveness with respect to the polarizing plate which is not subjected to the saponification process.

The thickness of the base material 13 varies depending on the type thereof. For example, in the case of an optical member, it is usually 10 m to 500 m, preferably 50 m to 300 m.

As the release sheets 12, 12a and 12b, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film , Polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, ethylene- (meth) acrylic acid copolymer film, ethylene- (meth) acrylic acid ester copolymer film, polystyrene film , Polycarbonate film, polyimide film, fluororesin film and the like can be used. Moreover, these crosslinked films can also be used. Furthermore, these laminated | multilayer film may be sufficient. On the other hand, it is preferable that the peeling sheets 12, 12a, 12b are active energy ray permeability.

It is preferable that the peeling process of the said peeling sheet is carried out to the peeling surface (especially the surface which contact | connects the adhesive layer 11). Examples of the releasing agent used in the peeling treatment include alkyd-based, silicone-based, fluorine-based, unsaturated polyester-based, polyolefin-based, and wax-based releasing agents.

Although there is no restriction | limiting in particular about the thickness of release sheet 12, 12a, 12b, Usually, it is about 20-150 micrometers.

In order to manufacture the said adhesive sheet 1A, the solution (coating solution) containing an adhesive composition (P) is apply | coated and dried to the peeling surface of the peeling sheet 12, and the coating film layer of adhesive composition P is formed. After that, the substrate 13 is laminated on the coating layer. And the adhesive layer 11 is formed by irradiating an active energy ray to the said coating film layer over the peeling sheet 12. Aging is unnecessary after active energy ray irradiation. In addition, it is as having mentioned above about irradiation conditions of an active energy ray.

In addition, in order to manufacture the said adhesive sheet 1B, the coating solution containing the said adhesive composition is apply | coated and dried to the peeling surface of one peeling sheet 12a (or (12b)), and the adhesive composition (P) After forming the coating film layer, the other release sheet 12b (or 12a) is laminated | stacked on this coating film layer. And the adhesive layer 11 is formed by irradiating an active energy ray to the said coating film layer over the peeling sheet 12a (or 12b).

Further, as described above, the active energy ray is irradiated over the release sheet to replace the adhesive layer 11 to form the coating layer of the adhesive composition P on the release sheet, and the coating layer is exposed. You may irradiate an active energy ray as it is, and form the adhesive layer 11, and after that, you may laminate | stack a base material and a peeling sheet in the said adhesive layer 11. Furthermore, you may form the coating film layer of the adhesive composition (P) directly on a base material, and irradiate an active energy ray to this coating film layer, and may form the adhesive layer 11.

As a method of apply | coating the said coating solution, the bar coating method, the knife coating method, the roll coating method, the blade coating method, the die coating method, the gravure coating method etc. can be used, for example.

Here, for example, in manufacturing the liquid crystal display device which consists of a liquid crystal cell and a polarizing plate, the polarizing plate is used as the base material 13 of the adhesive sheet 1A, and the release sheet 12 of the said adhesive sheet 1A is used. It is good to peel off and bond the exposed adhesive layer 11 and liquid crystal cell together.

In addition, for example, in manufacturing a liquid crystal display device in which a retardation plate is disposed between a liquid crystal cell and a polarizing plate, as an example, one of the release sheets 12a (or 12b) of the adhesive sheet 1B is first used. ) Is peeled off, and the exposed adhesive layer 11 and the retardation plate of the adhesive sheet 1B are bonded together. Next, the release sheet 12 of the pressure-sensitive adhesive sheet 1A using the polarizing plate as the base material 13 is peeled off, and the exposed pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet 1A is bonded to the retarder. Furthermore, the other peeling sheet 12b (or 12a) is peeled from the adhesive layer 11 of the said adhesive sheet B, and the exposed adhesive layer 11 and liquid crystal cell of the adhesive sheet B are removed. Put it together.

According to the above adhesive sheets 1A and 1B, since the adhesive layer 11 is excellent in durability, even if it is applied to adhesion | attachment of a polarizing plate, even if it is applied, for example, under high temperature or high temperature, high humidity, it raises, peeling, foaming, etc. It is prevented and suppressed.

The embodiments described above are described for ease of understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the said embodiment is the meaning including all the design changes and equivalents which belong to the technical scope of this invention.

For example, the release sheet 12 of the pressure-sensitive adhesive sheet 1A may be omitted, and either one of the release sheets 12a and 12b in the pressure-sensitive adhesive sheet 1B may be omitted.

[Examples]

Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples.

[Example 1]

1. Preparation of (meth) acrylic acid ester polymer

78.4 parts by weight of N-butyl acrylate, 20 parts by weight of methoxyethyl acrylate, 1.5 parts by weight of 2-hydroxyoxyethyl acrylate, N methacrylic acid to a reaction vessel equipped with a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube. 0.1 parts by weight of N-dimethylaminoethyl, 200 parts by weight of ethyl acetate and 0.08 parts by weight of 2,2'-azobisisobutylnitrile were added, and the air in the reaction vessel was replaced with nitrogen gas. While stirring under this nitrogen atmosphere, the reaction solution was heated to 60 ° C, reacted for 16 hours, and then cooled to room temperature. Here, the molecular weight was measured by the method of mentioning a part of obtained solution later, and production | generation of the (meth) acrylic acid ester polymer (polymer (A)) of the weight average molecular weight 1.3 million was confirmed.

2. Preparation of adhesive composition

100 parts by weight of the (meth) acrylic acid ester polymer (polymer (A)) obtained in the above step (1) (solid content conversion value; the same as below), and tris (acryloxyethyl) isocyanu as an active energy precurable component (B) After mixing 5 parts by weight of the rate (Toagosei Co., Aaronics M-315), and mixing benzophenone and 1-hydroxycyclohexylphenyl ketone in a weight ratio of 1: 1 as the photopolymerization initiator (C) (Chiba Specialty 0.5 parts by weight of Chemicals Co., Ltd. (IRGACURE 500), a hydrolysis condensation product of 3-mercaptopropyltrimethoxysilane-tetraethoxysilane as a silane coupling agent (D) (manufactured by Shin-Etsu Chemical Co., Ltd., X) -41-1810) 0.16 parts by weight and 2.0 parts by weight of 1-butyl-4-methylpyridinium hexafluorophosphate (manufactured by Tokyo Chemical Industry Co., Ltd.) as an antistatic agent are added, and the mixture is sufficiently stirred and diluted with ethyl acetate to give an adhesive property. A coating solution of the composition was obtained.

Here, the mixing | blending of this adhesive composition is shown in Table 1. In addition, the details, such as the symbol shown in Table 1, are as follows.

[(Meth) acrylic acid ester polymer]

BA: N-butyl acrylate

MEA: methoxy ethyl acrylate

HEA: 2-hydroxyethyl acrylate

DM: Methacrylic acid N, N-dimethylaminoethyl

DMAEA: N, N-dimethylaminoethyl acrylate

AA: acrylic acid

3. Manufacture of polarizing plate with pressure-sensitive adhesive layer

90 degreeC, after apply | coating the coating solution of the obtained adhesive composition to the peeling process surface of the peeling sheet (The Lintec company make, SP-PET3811, thickness: 38 micrometers) which peeled one side of the polyethylene terephthalate film with the silicone type peeling agent, The mixture was heated for 1 minute to form a coating layer of the adhesive composition.

Next, the polarizing plate not subjected to the saponification treatment was bonded to the exposed surface side of the coating layer. Then, the ultraviolet-ray was irradiated over the peeling sheet on condition of the following, and the said coating film layer was made into an adhesive layer, and the polarizing plate with an adhesive layer was obtained. In addition, the thickness of the adhesive layer was 20 micrometers.

<Ultraviolet irradiation condition>

Fusion electrode induction lamp H valve is used

Illuminance 600mW / cm ² , Light quantity 150mJ / cm ²

UV illuminance and photometer use "UVPF-36" made by iGraphics

[Examples 2-9, Comparative Examples 1-6]

Except for changing the type and proportion of each monomer constituting the (meth) acrylic acid ester polymer and the compounding amount of the active energy ray-curable component (B) and the photopolymerization initiator (C) as shown in Table 1, The polarizing plate with an adhesive layer was manufactured. On the other hand, in Example 9 and Comparative Example 4, two kinds of (meth) acrylic acid ester polymers are used, and in Comparative Examples 5 and 6, as one component of the adhesive composition, the triylene diisocyanate adduct of trimethylolpropane which is a thermal crosslinking agent ( The brand name "Coronate L" by the Japan Polyurethane Company was used.

Here, the weight average molecular weight (Mw) mentioned above is the weight average molecular weight of polystyrene conversion measured (GPC measurement) on condition of the following using gel permeation chromatography (GPC).

<Measurement Conditions>

· GPC measuring apparatus: HLC-8020 manufactured by Tosoh Corporation

GPC column (passed in the following order): manufactured by Tosoh Corporation

  TSK guard column HXL-H

  TSK gel GMHXL (× 2)

  TSK gel G2000 HXL

Measuring solvent: tetrahydrofuran

Measurement temperature: 40 ℃

[Test Example 1] (Measurement of gel fraction)

In the Example or the comparative example, it replaced with the polarizing plate used for preparation of the polarizing plate with an adhesive layer, and used the peeling sheet (SP-PET3801 made from Lintec, thickness: 38 micrometers) which peeled one side of the polyethylene terephthalate film with the silicone type peeling agent. And an adhesive sheet were produced. Specifically, the release sheet is laminated on the exposed coating layer of the structure consisting of the coating layer of the release sheet / adhesive composition obtained in the manufacturing process of the example or the comparative example so that the release treatment surface side is in contact with the above-mentioned release sheet. Ultraviolet light was irradiated under the same conditions. This produced the adhesive sheet which consists of a structure of a peeling sheet / adhesive layer / peeling sheet. In addition, the thickness of the adhesive layer was 20 micrometers.

The pressure-sensitive adhesive sheet produced as described above was sampled immediately after production (after ultraviolet irradiation and half a day later) at a size of 80 mm x 80 mm, and the pressure-sensitive adhesive layer was wrapped with a polyester mesh (mesh size 200) to prepare an adhesive. The weight of the bay was weighed on a precision balance. In addition, the adhesive sheet produced as mentioned above was stored for 7 days under conditions of 23 degreeC and 50% RH, and the weight of the adhesive only was weighed as mentioned above after that. Let this weight be M1.

Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate for 24 hours at room temperature (23 ° C). Then, the adhesive was taken out, air-dried for 24 hours in the environment of the temperature of 23 degreeC, and 50% of a relative humidity, and it dried for 12 hours in 80 degreeC oven. The weight of only the adhesive after drying was weighed by precision balance. Let the weight at this time be M2.

From the obtained M1 and M2, the following formula

Gel fraction (%) = (M2 / M1) × 100

By gel fraction G1 (%) immediately after adhesive sheet preparation (immediate adhesive layer formation) and gel fraction G2 (%) after storage for 7 days in 23 degreeC and 50% RH environment from adhesive sheet preparation (adhesive layer formation) Calculated.

In addition, from the obtained G1 and G2, the following formula | equation

Gel fraction variation (%) = | (G2-G1) / G2 | × 100

By this, the gel fraction variation rate (%) was calculated. The results are shown in Table 2.

[Test Example 2] (Measurement of Adhesive Force)

The polarizing plate with an adhesive layer obtained by the Example or the comparative example was cut out, and the sample of 25 mm width and 100 mm length was produced. As a sample, it stores for 7 days in the environment of 23 degreeC and 50% RH immediately after manufacture of the polarizing plate with an adhesive layer (immediately after adhesive layer formation, in other words, about half day from ultraviolet irradiation), and polarizing plate preparation with an adhesive layer (adhesive layer formation). After having prepared. The peeling sheet was peeled from these samples, the sample was affixed on alkali-free glass (Eagle XG, Corning Co., Ltd.) through the exposed pressure-sensitive adhesive layer, and then pressurized at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Corporation. . Then, after leaving for 24 hours under conditions of 23 degreeC and 50% RH, using an tensile tester (Tenshiron, made by Orientec Co., Ltd.), immediately after formation of an adhesive layer on the conditions of peeling rate 300mm / min and peeling angle 180 degrees. The adhesive force (S1: N / 25mm) and the adhesive force (S2: N / 25mm) after 7 days of storage were measured. Moreover, the adhesive force difference ((DELTA) S) which subtracted adhesive force immediately after adhesive layer formation from the adhesive force after 7 days storage was computed. The results are shown in Table 2.

[Test Example 3] (Durability Evaluation)

The polarizing plate with an adhesive layer obtained by the Example or the comparative example was cut out, and the sample of the magnitude | size of 233 mm x 309 mm was produced. As a sample, after storing for 7 days in the environment of 23 degreeC and 50% RH from the thing (H1) immediately after preparation of the polarizing plate with an adhesive layer (just after adhesive layer formation), and the preparation of the polarizing plate with adhesive layer (adhesive layer formation) (H2 Prepared). The peeling sheet was peeled off from these samples, and after affixing on alkali free glass (Eagle XG, Corning Co., Ltd.) through the exposed adhesive layer, it pressurized for 20 minutes at 0.5 Mpa and 50 degreeC by the autoclave by Kurihara Corporation.

Then, it put in the environment of the following durable conditions, and observed after 200 hours using the 10 times magnifier. The appearance change was based on the following. Table 2 shows the results for each sample of H1 and H2.

◎: There is not a fault in four sides

(Circle): No flaw in the part more than 0.6mm from the outer peripheral end in 4 sides

X: At least 1 side of 4 sides has an abnormality in the external appearance of 0.1 mm or more of adhesives, such as lifting, peeling, foaming, and a streak, in a site | part 0.6 mm or more from an outer peripheral end part.

 <Durability>

80 ℃ dry

60 ° C, 90% RH

Heat shock test for each 30 minutes at -35 ° C to 70 ° C, 200 cycles

[Test Example 4] (Measurement of Storage Modulus)

In the same manner as in Test Example 1, an adhesive sheet composed of a release sheet / adhesive layer / peel sheet was produced. The peeling sheet was peeled off from this adhesive sheet, and the adhesive layer was laminated | stacked in multiple layers so that it might become thickness 3mm. In the laminated body of the obtained adhesive layer, the cylinder (height 3mm) of diameter 8mm was punched out, and this was made into the sample.

About the said sample, storage elastic modulus (MPa) was measured on condition of the following conditions by the torsion shearing method using a viscoelasticity measuring instrument (DYNAMIC ANALAYZER by REOMETRIC company) based on JISK7244-6. The results are shown in Table 2.

Measuring frequency: 1Hz

Measurement temperature: 23 degrees Celsius

[Test Example 5] (Measurement of Surface Resistance)

The polarizing plate with an adhesive layer obtained by the Example or the comparative example was cut | disconnected in the magnitude | size of 50 mm x 50 mm, and the obtained sample was left to stand at the temperature of 23 degreeC, and humidity of 50% RH for 24 hours. Thereafter, the peeling sheet was peeled off, and the surface resistance value (Ω / sq) was measured according to JIS K6911 using a resistivity meter (manufactured by Mitsubishi Chemical Corporation, Hirestar UP MCP-HT450 type) on the exposed adhesive layer surface. . The results are shown in Table 2.

On the other hand, the surface resistance value is preferably 3.0 × 10 ¹¹ Ω / sq or less, particularly preferably 1.0 × 10 ¹¹ Ω / sq or less, and further preferably 8.0 × 10 ¹⁰ Ω / sq or less. When surface resistance value is below the said value, favorable antistatic property can be exhibited.

As can be seen from Table 2, the pressure-sensitive adhesive of the pressure-sensitive adhesive layer obtained in the examples, after the formation of the pressure-sensitive adhesive layer and after storage for 7 days, the variation of the gel fraction and the adhesive force was minute, and also excellent in durability.

The adhesive of this invention is suitable for adhesion | attachment of an optical member, especially a polarizing plate, and the adhesive sheet of this invention is suitable as an adhesive sheet for an optical member, especially a polarizing plate.

1A, 1B... Adhesive sheet
11 ... The pressure-
12, 12a, 12b... Peeling sheet
13 ... materials

Claims (13)

A (meth) acrylic acid ester polymer (A) having a weight average molecular weight of 600,000 to 2 million and containing a monomer having a nitrogen atom as a monomer unit constituting the polymer,
An active energy ray curable component (B) is contained, The adhesive composition characterized by the above-mentioned. The method according to claim 1,
The monomer having a nitrogen atom is a monomer having a tertiary amino group. The method according to claim 2,
The said monomer which has a tertiary amino group is at least 1 sort (s) chosen from acrylic acid N, N-dimethylaminoethyl, methacrylic acid N, and N-dimethylaminoethyl. The method according to claim 1,
The said (meth) acrylic acid ester polymer (A) contains 0.01-5.0 weight% of monomers which have the said nitrogen atom as a monomer unit which comprises the said polymer, The adhesive composition characterized by the above-mentioned. The method according to claim 1,
The ratio of the said active energy ray curable component (B) with respect to 100 weight part of said (meth) acrylic acid ester polymers (A) is 1-25 weight part, The adhesive composition characterized by the above-mentioned. The method according to claim 1,
The said adhesive composition contains a photoinitiator (C) further, The adhesive composition characterized by the above-mentioned. The method of claim 6,
Content of the said photoinitiator (C) is 2-15 weight part with respect to 100 weight part of said active energy ray curable components (B), The adhesive composition characterized by the above-mentioned. The adhesive which hardened the adhesive composition of any one of Claims 1-7 by irradiation of an active energy ray. The method according to claim 8,
The storage elastic modulus (G ') in 23 degreeC is 0.01-0.8 MPa, The adhesive characterized by the above-mentioned. A pressure-sensitive adhesive sheet comprising a substrate and a pressure-sensitive adhesive layer,
Said adhesive layer consists of an adhesive of Claim 8, The adhesive sheet characterized by the above-mentioned. The method according to claim 10,
Wherein the substrate is an optical member. The method of claim 11,
The optical member is a pressure-sensitive adhesive sheet, characterized in that the polarizing plate. Two release sheets,
And a pressure-sensitive adhesive layer sandwiched between the release sheets so as to come into contact with the release surfaces of the two release sheets,
Said adhesive layer consists of an adhesive of Claim 8, The adhesive sheet characterized by the above-mentioned.

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