KR20140102130A - adhesion composition, an adhesive and adhesion sheet - Google Patents

Abstract

Provided are an adhesive composition, an adhesive, and an adhesive sheet having improved durability, suitable for an optical member such as a polarizing plate. The adhesive composition contains: a (meth) acrylic acid ester polymer (A) containing 1.5 mass% or more of a monomer with hydroxyl group as a monomer unit forming the polymer; an isocyanate-based crosslinking agent (B); a silane coupling agent (C) with a mercapto group as a functional group reacting with an organic material; and an active energy ray-curable component (D).

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an adhesive composition, an adhesive and an adhesive sheet,

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive (a material obtained by curing a pressure-sensitive adhesive composition) and a pressure-sensitive adhesive sheet, and more particularly to a pressure-sensitive adhesive composition, a pressure-

2. Description of the Related Art In recent years, in many electronic apparatuses, a touch panel serving as both a display device and an input means has been widely used. The types of touch panels are mainly resistive, capacitive, optical and ultrasonic. Resistive films have analog resistors and matrix resistors. Capacitive capacitors have surface and projection types.

In touch panels in mobile electronic devices such as smart phones and tablet terminals, which are attracting attention recently, projection-type capacitive-type touch panels are widely used. As a projection type capacitive touch panel in such a mobile electronic device, for example, a liquid crystal display (LCD), a pressure sensitive adhesive layer, a transparent conductive film (indium tin oxide: ITO) It has been proposed that a protective layer such as a whole film (ITO) and a tempered glass is laminated.

As an optical component constituting the liquid crystal display device, a liquid crystal cell is generally used. The liquid crystal cell is generally formed by arranging two alignment layers of the transparent electrode substrate on which the alignment layers are formed with the inner side being spaced apart by a spacer and sealing the periphery thereof, I inserted the material. Normally, a polarizing plate is bonded to the outside of two transparent electrode substrates in a liquid crystal cell through a pressure-sensitive adhesive.

As a pressure sensitive adhesive for use in a touch panel, for example, it is known to be disclosed in Patent Document 1. The pressure-sensitive adhesive comprises a (meth) acryl-based polymer containing 0.2 to 20 parts by weight of a carboxyl group-containing monomer as a copolymerization component with respect to 100 parts by weight of an alkyl (meth) acrylate having an alkyl group having 4 to 14 carbon atoms as a monomer unit, ) 0.02 to 2 parts by weight of peroxide as a cross-linking agent, and 0.005 to 5 parts by weight of an epoxy cross-linking agent per 100 parts by weight of the acrylic polymer.

Patent Document 1: JP-A-2009-242786

In recent years, along with the thinning of mobile electronic devices, a polarizing plate as a constituent member has been made thinner, and a polarizing plate or the like using a protective film which is liable to cause an out-gas such as a cycloolefin polymer has been applied. Therefore, conventionally, a pressure-sensitive adhesive has been required to have high reliability (durability). However, the pressure-sensitive adhesive of Patent Document 1 has a problem that durability is low and lifting and peeling are likely to occur with time, under a high-temperature condition or under a moist heat condition.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet which are suitable for optical members such as polarizing plates.

In order to achieve the above object, the first aspect of the present invention is a polymer composition comprising (meth) acrylic acid ester polymer (A) containing 1.5% by mass or more of a monomer having a hydroxyl group as a monomer unit constituting the polymer, an isocyanate crosslinking agent , A silane coupling agent (C) having a mercapto group as a functional group reacting with an organic material, and an active energy ray-curable component (D) (Invention 1).

When the adhesive composition according to the invention (invention 1) is cured, the (meth) acrylic acid ester polymer (A), the isocyanate crosslinking agent (B) and the silane coupling agent (C) are crosslinked to form the first three- , And a plurality of active energy ray-curable components (D) combine to form a second three-dimensional network, and they are intertwined with each other and an integral three-dimensional network is formed. The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition has high durability due to the above-mentioned structure, and particularly excellent in durability at high temperature or under moist heat.

In the above invention (Invention 1), the (meth) acrylic acid ester polymer (A) has a weight average molecular weight of 1,000,000 to 2,500,000 and 1.8 to 10% by mass of a monomer having the hydroxyl group as a monomer unit constituting the polymer (Invention 2).

In the above invention (invention 1 or 2), it is preferable that the (meth) acrylic acid ester polymer (A) further contains 1 to 10 mass% of a monomer having an aromatic ring as a monomer unit constituting the polymer ).

In the above invention (Invention 3), the monomer having an aromatic ring is preferably 2-phenylethyl (meth) acrylate (Invention 4).

In the above invention (inventions 1 to 4), it is preferable that the (meth) acrylic acid ester polymer (A) does not contain a monomer having a carboxyl group as a monomer unit constituting the polymer (invention 5).

In the above inventions (Invention 1 to 5), the isocyanate crosslinking agent (B) is preferably trimethylolpropane-modified xylene diisocyanate (Invention 6).

In the above invention (Invention 1 to 6), the active energy ray-curable component (D) is preferably a polyfunctional acrylate-based monomer having a molecular weight of less than 1000 (Invention 7).

In the above invention (invention 7), the polyfunctional acrylate monomer preferably has a cyclic structure (invention 8).

In the above invention (Invention 1 to 8), the content of the active energy ray-curable component (D) in the viscous composition is 5 to 20 parts by mass relative to 100 parts by mass of the (meth) acrylic acid ester polymer (A) (Invention 9).

The second invention provides a pressure-sensitive adhesive which cures the adhesive composition (Invention 1 to 9) by irradiation of an active energy ray (invention 10).

In the invention (Invention 10), it is preferable that the gel fraction after storage for 7 days under the environment of 23 ° C and 50% RH from the pressure-sensitive adhesive layer formation is 75 to 95% (invention 11).

It is preferable that the storage elastic modulus (G ') at 23 ° C is 0.05 to 0.20 MPa and the storage elastic modulus (G') at 80 ° C is 0.05 to 0.15 MPa in the above invention (Inventions 10 and 11) .

The third aspect of the present invention provides a pressure-sensitive adhesive sheet comprising a substrate and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive (Invention 10 to 12).

In the invention (invention 13), it is preferable that the substrate is an optical member (invention 14).

In the invention (invention 14), it is preferable that the optical member is a polarizing plate (invention 15).

A fourth aspect of the present invention is a pressure-sensitive adhesive sheet comprising two release sheets and a pressure-sensitive adhesive layer sandwiched between the release sheets so as to contact the release surfaces of the two release sheets, wherein the pressure- (16). ≪ Desc / Clms Page number 17 >

Since the pressure-sensitive adhesive composition according to the present invention contains the components (A) to (D), the resulting pressure-sensitive adhesive has high durability and is suitable for optical members such as polarizing plates.

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

Hereinafter, embodiments of the present invention will be described.

[Adhesive composition]

(Hereinafter referred to as " sticky composition P ") according to the present embodiment comprises a (meth) acrylic acid ester polymer (A) containing 1.5% by mass or more of a monomer having a hydroxyl group as a monomer unit constituting the polymer, Based crosslinking agent (B), a silane coupling agent (C) having a mercapto group as a functional group reacting with an organic material, and an active energy ray-curable component (D). In the present specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same is true of other similar terms. The term " polymer " includes the concept of " copolymer ".

When the viscous composition P is cured, the mercapto group of the silane coupling agent (C) easily forms a thiourethane bond with the isocyanate group of the isocyanate crosslinking agent (B), and the other isocyanate groups of the isocyanate crosslinking agent (B) (Meth) acrylic acid ester polymer (A) is reacted with the hydroxyl group of the (meth) acrylic acid ester polymer (A) to form a first three-dimensional network structure. It is presumed that the alkoxysilyl group of the silane coupling agent (C) has a proper distance from the (meth) acrylic acid ester polymer (A) and is in a form suspended from the (meth) acrylic acid ester polymer (A). On the other hand, the plurality of active energy ray-curable components (D) combine with each other to form a second three-dimensional network structure. It is assumed that the first three-dimensional network structure and the second three-dimensional network structure are entangled with each other to form an integral three-dimensional network structure (this structure is hereinafter referred to as "structure X").

In the pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P, the durability is improved by the structure X described above. Particularly, it is presumed that the alkoxysilyl group possessed by the silane coupling agent (C) is present at a proper distance from the (meth) acrylic acid ester polymer (A) and further from the structure X, thereby exerting an excellent coupling effect. Accordingly, it is considered that the obtained pressure-sensitive adhesive is excellent in adhesion durability even under a high-temperature condition or under a moist heat condition.

(1) The (meth) acrylic acid ester polymer (A)

The (meth) acrylic acid ester polymer (A) contains a monomer (a hydroxyl group-containing monomer) having a hydroxyl group as a monomer unit constituting the polymer. Thereby, the (meth) acrylic acid ester polymer (A) has a hydroxyl group. The hydroxyl group is highly reactive with the isocyanate group of the isocyanate crosslinking agent (B), and the (meth) acrylic acid ester polymer (A) is crosslinked by the isocyanate crosslinking agent (B) by such a reaction.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (Meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. Of these, from the viewpoint of reactivity with the isocyanate crosslinking agent (B) 2-hydroxyethyl methacrylate is preferable. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (A) is required to contain 1.5 mass% or more of a hydroxyl group-containing monomer as a monomer unit constituting the polymer, preferably 1.8 to 10 mass% By mass, more preferably 2 to 5% by mass. When the content of the hydroxyl group-containing monomer is within the above range, the crosslinking structure to be formed becomes good, and the obtained pressure-sensitive adhesive has excellent durability. If the content of the hydroxyl group-containing monomer is less than 1.5% by mass, the crosslinking point is too small, and the resulting pressure-sensitive adhesive can not exhibit excellent durability. On the other hand, when the content of the hydroxyl group-containing monomer exceeds 10% by mass, the crosslinking point is too large, and the obtained pressure-sensitive adhesive is not flexible, and the stress relaxation property is likely to decrease.

The (meth) acrylic acid ester polymer (A) preferably contains a monomer (aromatic ring-containing monomer) having an aromatic ring as a monomer unit constituting the polymer. Thereby, the (meth) acrylic acid ester polymer (A) has an appropriate hardness, and the resulting pressure-sensitive adhesive is excellent in durability.

Examples of the aromatic ring-containing monomer include phenyl (meth) acrylate, 2-phenylethyl (meth) acrylate, benzyl (meth) acrylate, naphthyl (meth) acrylate, phenoxyethyl (Meth) acrylate, phenoxydiethylene glycol (meth) acrylate, ethylene oxide-modified cresol (meth) acrylate, ethylene oxide (EO) -modified nonylphenol Among them, 2-phenylethyl (meth) acrylate is preferable from the viewpoint of polymerizability. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (A) preferably contains 1 to 10 mass%, particularly preferably 2 to 8 mass%, of the aromatic ring-containing monomer as the monomer unit constituting the polymer, More preferably in a mass%. When the content of the aromatic ring-containing monomer is within the above range, the resulting pressure-sensitive adhesive has better durability. When the content of the aromatic ring-containing monomer is less than 1% by mass, inconvenience of light leakage may occur when the obtained pressure-sensitive adhesive is used for a polarizing plate application or the like. On the other hand, when the content of the aromatic ring-containing monomer exceeds 10% by mass, the durability of the obtained pressure-sensitive adhesive may be deteriorated.

The (meth) acrylic acid ester polymer (A) preferably contains a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer, and is particularly preferably contained as a main component. Thereby, the resulting pressure-sensitive adhesive can exhibit desirable tackiness.

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, n-pentyl acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl Myristyl, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Among them, (meth) acrylic acid esters having an alkyl group of 1 to 4 carbon atoms are preferable, and methyl (meth) acrylate and n-butyl (meth) acrylate are particularly preferable from the viewpoint of further improving the tackiness. These may be used alone or in combination of two or more.

The (meth) acrylic acid ester polymer (A) preferably contains 50 to 97.5 mass% of a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer, more preferably 80 to 96 mass% %, More preferably from 85 to 95 mass%.

The (meth) acrylic acid ester polymer (A) may contain other monomers as monomer units constituting the polymer, if desired. The other monomer may be a monomer having a reactive functional group (a reactive functional group-containing monomer), or a non-reactive monomer.

Examples of the reactive functional group-containing monomer include a monomer having a carboxyl group (a carboxyl group-containing monomer) and a monomer having an amino group (an amino group-containing monomer).

Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid. These may be used alone or in combination of two or more.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate. These may be used alone or in combination of two or more.

In the case where the object to which the obtained pressure-sensitive adhesive adheres is caused by an acid, for example, in the case of a transparent conductive film or a metal film, the (meth) acrylic acid ester polymer (A) Containing monomer is preferably not contained. Thus, for example, when the object to be pasted is a transparent conductive film, it is possible to inhibit the transparent conductive film from being corroded or changing the resistance value of the transparent conductive film. The silane coupling agent (C) having a mercapto group is effective also in such an acid-free system.

Examples of the non-reactive monomer include (meth) acrylic acid alkoxyalkyl esters such as methoxyethyl (meth) acrylate and ethoxyethyl (meth) acrylate, and aliphatic rings such as (meth) acrylate cyclohexyl (Meth) acrylic acid, N, N-dimethylaminoethyl, (meth) acrylic acid N, N-dimethylaminopropyl, and the like, which are not crosslinked, such as acrylic acid ester, acrylamide and methacrylamide (Meth) acrylic acid esters, vinyl acetate, and styrene. These may be used alone or in combination of two or more.

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

The weight average molecular weight of the (meth) acrylic acid ester polymer (A) is preferably from 1 million to 2.5 million, more preferably from 1.4 million to 2.2 million, and further preferably from 1.7 million to 2 million. In the present specification, the weight average molecular weight is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

If the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is less than 1,000,000, the resulting pressure-sensitive adhesive may have poor durability. When the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is more than 250,000, the resulting pressure-sensitive adhesive may be inferior in stress relaxation property.

In the adhesive composition P, the (meth) acrylic acid ester polymer (A) may be used singly or in combination of two or more kinds.

(2) isocyanate-based crosslinking agent (B)

The isocyanate crosslinking agent (B) has an advantage of excellent reactivity with the mercapto group of the silane coupling agent (C). In addition, the (meth) acrylic acid ester polymer (A) has an advantage of being excellent in reactivity with the hydroxyl group.

The isocyanate-based crosslinking agent (B) contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane Alicyclic polyisocyanates such as diisocyanate and the like, and a reaction product thereof with a low molecular active hydrogen-containing compound such as a biuret, an isocyanurate, or an ethylene glycol, propylene glycol, neopentyl glycol, trimethylol propane, And duct duct bodies. From the viewpoint of improving durability, trimethylolpropane-modified aromatic polyisocyanates, especially trimethylolpropane-modified xylylene diisocyanate, are preferred. The isocyanate crosslinking agent (B) may be used singly or in combination of two or more.

The content of the isocyanate crosslinking agent (B) in the adhesive composition P is preferably from 0.1 to 1 part by mass, particularly preferably from 0.2 to 0.8 part by mass, more preferably from 0.2 to 0.8 part by mass based on 100 parts by mass of the (meth) acrylic acid ester polymer (A) More preferably 0.5 parts by mass. When the content of the isocyanate crosslinking agent (B) is in the above range, a crosslinked structure which does not inhibit the stress relaxation property in the obtained pressure-sensitive adhesive can be formed and the durability is excellent.

(3) Silane coupling agent (C)

The silane coupling agent (C) in the present embodiment has a mercapto group as a functional group that reacts with an organic material. Since the mercapto group easily reacts with the isocyanate group of the isocyanate crosslinking agent (B), the (meth) acrylic acid ester polymer (A) has a hydroxyl group which is difficult to function in a general silane coupling agent (even if the (meth) acrylic acid ester polymer (A) does not contain a carboxyl group as a crosslinkable functional group), and the silane coupling agent The coupling effect can be obtained.

As described above, in the pressure-sensitive adhesive in which the pressure-sensitive adhesive composition P is cured, the alkoxysilyl group of the silane coupling agent (C) is removed from the (meth) acrylic acid ester polymer (A) at a suitable distance, that is, a plurality of isocyanate groups Acrylic acid ester polymer (A) with a distance therebetween. As described above, since the alkoxysilyl group is present at a proper distance from the (meth) acrylic acid ester polymer (A) and further from the structure X, a superior coupling effect can be exhibited and the resulting pressure sensitive adhesive can be obtained even under high- The durability of adhesion is excellent. This effect is particularly remarkable in the case of an inorganic material such as glass or metal to which the adhesive is applied.

As the silane coupling agent (C), an organosilicon compound having at least one mercapto group and at least one alkoxysilyl group in the molecule and having good compatibility with the pressure-sensitive adhesive component and having light transmission property, for example, It is very suitable.

Specific examples of such a silane coupling agent (C) include a mercapto group-containing low-molecular-weight silane coupling agent such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyldimethoxymethylsilane Ring agent; Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane and 3-mercaptopropyldimethoxymethylsilane, and silane compounds containing a mercapto group such as methyltriethoxysilane, ethyltriethoxysilane, Containing oligomer-type silane coupling agent such as a co-condensation product of an alkyl group-containing silane compound such as methyltrimethoxysilane and ethyltrimethoxysilane. Among them, from the viewpoint of improving durability, a mercapto group-containing oligomer type silane coupling agent is preferable, and particularly, a cocondensation product of a mercapto group-containing silane compound and an alkyl group-containing silane compound is preferable, and 3-mercaptopropyltrimethoxy More preferred is a co-condensation product of silane and methyltriethoxysilane. These may be used singly or in combination of two or more kinds.

The content of the silane coupling agent (C) in the sticky composition P is preferably 0.05 to 1 part by mass, particularly preferably 0.1 to 0.8 part by mass, more preferably 0.2 to 1 part by mass based on 100 parts by mass of the (meth) acrylic acid ester polymer (A) More preferably 0.5 parts by mass. When the content of the silane coupling agent (C) is less than 0.05 part by mass, it is difficult to obtain an effect of improving the durability of the silane coupling agent (C). On the other hand, if the content of the silane coupling agent (C) exceeds 1 part by mass, the reaction between the isocyanate crosslinking agent (B) and the (meth) acrylic acid ester polymer (A) may be inhibited.

(4) Active energy ray-curable component (D)

The active energy ray-curable component (D) is not particularly limited as long as it does not interfere with the effect of the present invention and is cured by irradiation with active energy rays, and may be any of monomers, oligomers or polymers, or a mixture thereof. Among them, polyfunctional acrylate-based monomers having a molecular weight of less than 1,000 and excellent compatibility with the (meth) acrylic acid ester polymer (A) are preferably used.

Examples of the polyfunctional acrylate monomer having a molecular weight of less than 1,000 include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di Acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone Bifunctional types such as modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified di (meth) acrylate, di (acryloxyethyl) isocyanurate, and arylated cyclohexyl di (meth) acrylate; (Meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri Trifunctional types such as thylol propane tri (meth) acrylate and tris (acryloxyethyl) isocyanurate; Tetrafunctional types such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; Pentafunctional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; And hexafunctional types such as dipentaerythritol hexa (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate. These may be used singly or in combination of two or more kinds.

Among the polyfunctional acrylate monomers, those having a cyclic structure in the backbone are preferable from the viewpoint of improving durability. The cyclic structure may be a carbon cyclic structure or a heterocyclic structure, and may be a monocyclic structure or a polycyclic structure. Examples of such multifunctional acrylate monomers include monomers having an isocyanurate structure such as di (acryloxyethyl) isocyanurate and tris (acryloxyethyl) isocyanurate, Pentane diacrylate, ethylene oxide modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, and adamantane diacrylate.

As the active energy ray-curable component (D), an active energy ray-curable acrylate oligomer may be used. The acrylate oligomer preferably has a weight average molecular weight of 50,000 or less. Examples of such acrylate oligomers include polyester acrylate, epoxy acrylate, urethane acrylate, polyether acrylate, polybutadiene acrylate, and silicone acrylate.

Here, the polyester acrylate oligomer can be obtained, for example, by esterifying a hydroxyl group of a polyester oligomer having hydroxyl groups at both terminals obtained by condensation of a polyhydric alcohol with a polyhydric alcohol with (meth) acrylic acid, Can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to the main chain with (meth) acrylic acid. The epoxy acrylate oligomer can be obtained, for example, by reacting an oxirane ring of a relatively low molecular weight bisphenol type epoxy resin or novolak type epoxy resin with (meth) acrylic acid to effect esterification. An epoxy acrylate oligomer having a carboxyl-modified form obtained by partially modifying the epoxy acrylate oligomer with an alkaline carboxylic acid anhydride may also be used. The urethane acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by the reaction of a polyether polyol or a polyester polyol with a polyisocyanate with (meth) acrylic acid. The polyol acrylate oligomer can be obtained by esterifying the hydroxyl group of the polyether polyol with (meth) acrylic acid.

The weight average molecular weight of the acrylate oligomer is preferably 50,000 or less, more preferably 500 to 50,000, and even more preferably 3,000 to 40,000. These acrylate oligomers may be used singly or in combination of two or more.

As the active energy ray curable component (D), an acryl acrylate polymer having a group having a (meth) acryloyl group introduced into its side chain may be used. Such an adduct acrylate-based polymer is obtained by using a copolymer of a (meth) acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and adding a (meth) acryloyl group and a crosslinking property to a part of the crosslinkable functional group of the copolymer Can be obtained by reacting a compound having a group which reacts with a functional group.

As the (meth) acrylic acid ester, those containing an alkyl (meth) acrylate ester in which the alkyl group has 1 to 20 carbon atoms are preferable. Examples thereof include methyl (meth) acrylate, ethyl (meth) acrylate, Propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate and stearyl (meth) acrylate. These may be used alone or in combination of two or more.

The monomer having a crosslinkable functional group in the molecule preferably contains at least one kind selected from a hydroxyl group, a carboxyl group, an amino group and an amide group as a functional group. Examples of such monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl Hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate and the like; Acrylamides such as acrylamide, methacrylamide, N-methyl acrylamide, N-methyl methacrylamide, N-methylol acrylamide and N-methylol methacrylamide; (Meth) acrylic acid monoalkylaminoalkyl such as monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate and monoethylaminopropyl (meth) acrylate; And ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid and citraconic acid. These monomers may be used alone or in combination of two or more.

Examples of the compound having a (meth) acryloyl group and a group capable of reacting with a crosslinkable functional group include acryloyloxyethyl isocyanate, acryloyloxypropyl isocyanate, methacryloyloxyethyl isocyanate, methacryloyloxy Propyl isocyanate and the like. These may be used alone or in combination of two or more.

The weight average molecular weight of the adduct acrylate-based polymer is preferably about 500,000 to 2,000,000.

As the active energy ray-curable component (D), one kind or two or more kinds of the above-mentioned polyfunctional acrylate-based monomer, acrylate-based oligomer and adduct acrylate-based polymer may be used, And may be used in combination with other active energy ray-curable components.

The content of the active energy ray-curable component (D) in the sticky composition P is preferably 5 to 20 parts by mass, more preferably 6 to 15 parts by mass, per 100 parts by mass of the (meth) acrylic acid ester polymer (A) , And more preferably 7 to 12 parts by mass. The pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition P containing the active energy ray-curable component (D) in this range is presumed to form the structure X satisfactorily.

(5) Photopolymerization initiator (E)

Here, when ultraviolet rays are used as the active energy ray to be irradiated on the sticky composition P, it is preferable that the sticky composition P further contains a photopolymerization initiator (E). By containing the photopolymerization initiator (E) in this way, the active energy ray curable component (D) can be efficiently cured, and the polymerization curing time and irradiation amount of the active energy ray can be reduced.

Examples of the photopolymerization initiator (E) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, Phenylacetophenone, 2,2-diethoxy 2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclo Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 4- (2-hydroxyethoxy) phenyl- 2- -Propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methyl anthraquinone, 2-ethyl anthraquinone, 2- -Aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, Phenon dimethyl ketal, p- Methylbenzoyl-diphenyl-phosphine oxide, and the like can be used in combination with an organic solvent such as methylene aminobenzoic acid ester, oligo [2-hydroxy-2-methyl- . These may be used alone or in combination of two or more.

The photopolymerization initiator (E) is preferably used in an amount of 2 to 15 parts by mass, particularly 5 to 12 parts by mass, based on 100 parts by mass of the active energy ray-curable component (D).

(6) Various additives

Various additives commonly used in acrylic pressure sensitive adhesives such as an antistatic agent, a tackifier, an antioxidant, an ultraviolet absorber, a light stabilizer, a softening agent, a filler, and a refractive index adjuster may be added to the adhesive composition P, if desired.

Examples of the antistatic agent include an ionic liquid, an ionic solid, an anionic surfactant, an alkali metal salt, a cationic surfactant, and a nonionic surfactant. Of these, an ionic liquid, It is preferable to use at least one selected from solid and alkali metal salts.

As the ionic liquid and the ionic solid, preferred are a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus iononium salt. The alkali metal salt is preferably a lithium salt, a potassium salt or the like. These may be used alone or in combination of two or more.

The content of the antistatic agent in the adhesive composition P is preferably from 0.1 to 10 mass%, more preferably from 1 to 5 mass%. When the content of the antistatic agent is within the above range, the balance between the antistatic performance and the durability of the pressure-sensitive adhesive is improved.

[Production method of adhesive composition]

The adhesive composition P is obtained by preparing a (meth) acrylic acid ester polymer (A) and reacting the obtained (meth) acrylic acid ester polymer (A), an isocyanate crosslinking agent (B), a silane coupling agent (D), and optionally adding a photopolymerization initiator (E), an additive and the like in an optional step.

The (meth) acrylic acid ester polymer (A) can be produced by polymerizing a monomer (a monomer mixture in the case of a copolymer) constituting the polymer by a conventional radical polymerization method. The polymerization of the (meth) acrylic acid ester polymer (A) can be carried out by a solution polymerization method or the like, using a polymerization initiator if desired. As the polymerization solvent, for example, ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone and the like may be used.

Examples of the polymerization initiator include an azo compound, an organic peroxide, and the like, and two or more of them may be used in combination. Examples of the azo based compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane- (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxy valeronitrile), dimethyl 2,2 ' Azobis (2-methylpropionate), 4,4'-azobis (4-cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile) -Azobis [2- (2-imidazolin-2-yl) propane].

Examples of the organic peroxide include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di (2-ethoxyethyl) Carbonate, t-butyl peroxyneodecanoate, t-butyl peroxybibarate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, and diacetyl peroxide.

In addition, in the above-mentioned polymerization step, the weight average molecular weight of the obtained polymer can be controlled by blending a chain transfer agent such as 2-mercaptoethanol.

(B), a silane coupling agent (C), an active energy ray-curable component (D), and an isocyanate-based crosslinking agent (B) are added to a solution of the (meth) acrylic acid ester polymer A photopolymerization initiator (E), an additive and the like are added in accordance with desirability and sufficiently mixed to obtain a sticky composition P (coating solution) diluted with a solvent.

Examples of the diluting agent for diluting the adhesive composition P into a coating solution include aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; , Alcohols such as ethanol, 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 cellosolve solvents such as cellosolve are used.

The concentration and viscosity of the coating solution thus produced may be in a range that can be coated, and are not particularly limited and can be appropriately selected depending on the situation. For example, it is diluted such that the concentration of the sticky composition P is 10 to 40% by mass. In addition, when obtaining a coating solution, it is not necessary to add a diluting solvent or the like, and it is not necessary to add a diluting solvent if the viscosity of the adhesive composition P is such as to be a coating. In this case, the adhesive composition P becomes the coating solution as it is.

[adhesive]

The pressure-sensitive adhesive of the present embodiment can be preferably obtained by applying the pressure-sensitive adhesive composition P to a desired object, drying it, and then curing the pressure-sensitive adhesive composition P by irradiation with active energy rays.

The drying of the sticky composition P may be performed by wind drying, but is usually carried out by a heat treatment (preferably, hot air drying). In the case of performing the heat treatment, the heating temperature is preferably 50 to 150 占 폚, particularly preferably 70 to 120 占 폚. The heating time is preferably 10 seconds to 10 minutes, more preferably 50 seconds to 2 minutes.

As the active energy ray, ultraviolet ray, electron beam and the like are usually used. The irradiation amount of the active energy ray varies depending on the kind of the energy ray. For example, in the case of ultraviolet ray, the amount of the active energy ray is preferably 50 to 1000 mJ / cm2, more preferably 100 to 500 mJ / cm2. In the case of electron beam, it is preferably about 10 to 1000 krad.

(Meth) acrylic acid ester polymer (A) having a hydroxyl group is crosslinked by an isocyanate crosslinking agent (B) to form a first three-dimensional network structure, and a plurality of active The energy ray curable components (D) combine with each other to form a second three-dimensional network structure, and they are intertwined with each other and it is presumed that the structure X described above is formed. The mercapto group of the silane coupling agent (C) readily reacts with the isocyanate group of the isocyanate crosslinking agent (B), and the remaining isocyanate group of the isocyanate crosslinking agent (B) reacts with the hydroxyl group of the (meth) It is presumed to react. In this way, the alkoxysilyl group of the silane coupling agent (C) is present at an appropriate distance from the (meth) acrylic acid ester polymer (A) and further from the structure X through the isocyanate crosslinking agent (B) I will exert.

The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P has excellent durability due to the structure X described above, and particularly excellent adhesion durability even under high temperature or high humidity conditions owing to the excellent coupling effect by the silane coupling agent (C) I will exert. For example, it is prevented and suppressed that peeling, peeling, air bubbles, and the like are generated even when the substrate is heated at a high temperature of 80 캜 or under a wet heat condition of 60 캜 and 90% RH for 250 hours.

The gel fraction of the pressure sensitive adhesive according to the present embodiment is preferably 75 to 95%, more preferably 80 to 92%. If the gel fraction is less than 75%, the cohesive force of the pressure-sensitive adhesive may be insufficient and durability and reworkability may be deteriorated. On the other hand, if the gel fraction exceeds 90%, the adhesive force becomes too low and the durability may deteriorate. Further, the gel fraction is a value after storage of the pressure-sensitive adhesive layer for 7 days (at the end of the curing period) in an environment of 23 ° C and 50% RH. When it is unclear whether or not the curing period has elapsed, the gel fraction may be kept within the above range after being stored again for 7 days under the environment of 23 ° C and 50% RH.

The storage elastic modulus (G ') at 23 deg. C of the pressure sensitive adhesive according to the present embodiment is preferably 0.05 to 0.20 MPa, more preferably 0.08 to 0.17 MPa, and even more preferably 0.10 to 0.16 MPa. Further, the storage elastic modulus (G ') of the pressure-sensitive adhesive according to the present embodiment at 80 ° C is preferably 0.05 to 0.15 MPa, more preferably 0.08 to 0.14 MPa, and further preferably 0.10 to 0.12 MPa. When the storage elastic modulus (G ') at 23 DEG C and 80 DEG C is within the above range, desired substrate adhesion and cohesive force can be obtained, and when applied to an optical member such as a polarizing plate, It is possible to effectively prevent lifting or peeling off the interface with the optical member or the interface with the glass substrate. The storage elastic modulus is a value measured by a twisting shear method at a measurement frequency of 1 Hz in accordance with JIS K7244-6.

[Adhesive sheet]

1, the pressure-sensitive adhesive sheet 1A according to the first embodiment comprises a release sheet 12, a pressure-sensitive adhesive layer 11 laminated on the release surface of the release sheet 12, And a substrate 13 laminated on the pressure-sensitive adhesive layer 11. [

2, the pressure-sensitive adhesive sheet 1B according to the second embodiment is constituted by two sheets of release sheet 12a, 12b and a pair of release sheets 12a, And a pressure-sensitive adhesive layer 11 sandwiched between two release sheets 12a and 12b. Furthermore, the release surface of the release sheet in the present specification means a surface having release properties in the release sheet, and includes both the surface subjected to the release treatment and the surface exhibiting the release property without performing the release treatment.

In any of the pressure-sensitive adhesive sheets 1A, 1B, the pressure-sensitive adhesive layer 11 is composed of a pressure-sensitive adhesive that cures the pressure-sensitive adhesive composition described above.

The thickness of the pressure-sensitive adhesive layer 11 is appropriately determined according to the intended use of the pressure-sensitive adhesive sheets 1A and 1B, but is usually in the range of 5 to 100 占 퐉, preferably 10 to 60 占 퐉, And when it is used as a pressure-sensitive adhesive layer for a polarizing plate, it is preferably 10 to 50 탆, particularly 15 to 30 탆.

The base material (13) is not particularly limited, and any material used as a base sheet of a conventional adhesive sheet can be used. For example, in addition to a desired optical member, a woven or nonwoven fabric using fibers such as rayon, acrylic, and polyester; Synthetic paper; Papers such as paper, paper, glossy paper, impregnated paper, coated paper; Metal foil such as aluminum or copper; Foams such as urethane foams and polyethylene foams; A polyethylene film, a polyethylene film, a polypropylene film, a cellulose film such as triacetylcellulose, a polyvinyl chloride film, a polyvinylidene chloride film, a polyvinylidene chloride film, a polyvinylidene chloride film, a polyethylene terephthalate film, A plastic film such as a vinyl alcohol film, an ethylene-vinyl acetate copolymer film, a polystyrene film, a polycarbonate film, an acrylic resin film, a norbornene resin film, and a cycloolefin resin film; A laminate of two or more kinds thereof, and the like. The plastic film may be uniaxially or biaxially stretched.

Examples of the optical member include a polarizing plate (polarizing film), a polarizer, a retardation film (retardation film), a viewing angle compensating film, a luminance improving film, a contrast enhancing film, a liquid crystal polymer film, a diffusing film, . As the polarizing plate, preferably, a triacetyl cellulose (TAC) film is laminated on both surfaces of a polyvinyl alcohol polarizer, or a polarizing plate in which one TAC film is changed to a film of a cycloolefin polymer (hereinafter referred to as a "COP polarizing plate" ) Is used. The pressure-sensitive adhesive layer 11 according to the present embodiment exhibits excellent adhesiveness to the above-described substrates, and particularly to a polarizing plate, particularly a COP polarizing plate.

The thickness of the base material 13 varies depending on the kind thereof, but in the case of, for example, an optical member, it is usually from 10 탆 to 500 탆, preferably from 50 탆 to 300 탆, particularly preferably from 80 탆 to 150 탆 .

Examples of the release sheets 12, 12a and 12b include a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, a polyethylene terephthalate film , Ethylene / (meth) acrylic acid copolymer film, ethylene / (meth) acrylic acid ester copolymer film, polystyrene film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate film, ionomer resin film, , A polycarbonate film, a polyimide film, a fluororesin film and the like are used. These crosslinked films are also used. These may be laminated films. It is also preferable that the release sheets 12, 12a, and 12b are active energy ray transmissive.

It is preferable that a peeling treatment is performed on the peeling surface of the peeling sheet (in particular, the surface in contact with the peeling layer 11). Examples of the releasing agent used in the peeling treatment include an alchid type, a silicone type, a fluorine type, an unsaturated polyester type, a polyolefin type, and a wax type releasing agent.

The thickness of the release sheets 12, 12a, 12b is not particularly limited, but is usually about 20 to 150 mu m.

In producing the pressure-sensitive adhesive sheet 1A, a solution (coating solution) containing the pressure-sensitive adhesive composition P is applied and dried on the release surface of the release sheet 12 to form a pressure-sensitive adhesive layer composition layer P, A substrate 13 is laminated on the layer. Then, the adhesive layer 11 is formed by irradiating the coating film layer with an active energy ray over the release sheet 12. The irradiation conditions of the active energy ray are as described above.

When the pressure-sensitive adhesive sheet 1B is produced, a coating solution containing the pressure-sensitive adhesive composition is applied and dried on the release surface of one release sheet 12a (or 12b) to form a coating layer of the pressure- And the other release sheet 12b (or 12a) is laminated on the coating layer. Then, the adhesive layer 11 is formed by irradiating the coating film layer with an active energy ray over the peeling sheet 12a (or 12b).

Instead of forming the pressure-sensitive adhesive layer 11 by irradiating the active energy ray over the release sheet as described above, a coating layer of the pressure-sensitive adhesive composition P is formed on the release sheet, and the active energy The adhesive layer 11 may be formed by irradiating the adhesive layer 11 with a substrate or a release sheet. Alternatively, a pressure-sensitive adhesive layer 11 may be formed by forming a coating layer of a direct-sticking composition P on a substrate and irradiating the coating film layer with an active energy ray.

As a method of applying the coating solution, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method and the like can be used.

The pressure-sensitive adhesive layer 11 in the pressure-sensitive adhesive sheets 1A and 1B preferably has a haze value (measured according to JIS K7136: 2000) of 1.0% or less, more preferably 0.9% or less, and more preferably 0.8% desirable. When the haze value is 1.0% or less, the transparency is very high and is suitable for optical use.

Here, for example, when a liquid crystal display device comprising a liquid crystal cell and a polarizing plate is manufactured, a polarizing plate is used as the base material 13 of the pressure-sensitive adhesive sheet 1A, and the release sheet 12 of the pressure- Peeled, and the exposed pressure-sensitive adhesive layer 11 and the liquid crystal cell are laminated.

For example, when manufacturing a liquid crystal display device in which a retarder plate is disposed between a liquid crystal cell and a polarizing plate, one of the release sheets 12a (or 12b) of the pressure-sensitive adhesive sheet 1B is first peeled off, The exposed pressure-sensitive adhesive layer 11 of the sheet 1B and the retarder are bonded. 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. The other release sheet 12b (or 12a) is peeled from the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet B and the pressure-sensitive adhesive layer 11 of the pressure-sensitive adhesive sheet B is bonded to the liquid crystal cell.

According to the pressure-sensitive adhesive sheets 1A and 1B described above, since the pressure-sensitive adhesive layer 11 is excellent in durability, the pressure-sensitive adhesive sheet 11 can be peeled off and peeled off from the substrate 13 such as a COP polarizer or the adherend under high- , Foaming and the like are prevented or suppressed.

In the adhesive sheets 1A and 1B according to the present embodiment, it is also preferable to use a transparent conductive film as an adherend. In this case, it is preferable that the (meth) acrylic acid ester polymer (A) in the sticky composition P does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. Thus, it is possible to suppress the adverse effect of the acid component on the transparent conductive film as the adherend. Concretely, it is possible to inhibit the transparent conductive film from being corroded or from changing the resistance value of the transparent conductive film.

Examples of the transparent conductive film include metals such as platinum, gold, silver and copper, oxides such as tin oxide, indium oxide, cadmium oxide, zinc oxide and zinc dioxide, indium tin oxide (ITO) A composite oxide such as indium oxide, indium fluoride-doped tin oxide, antimony doped tin oxide, fluorine doped tin oxide or aluminum-doped zinc oxide, non-oxidized compounds such as chalcogenide, lanthanum boron nitride, titanium nitride and titanium carbide .

The adhesive sheet 1A using a polarizing plate as the substrate 13 (hereinafter sometimes referred to as a "polarizing plate with a pressure-sensitive adhesive layer") preferably has an adhesive force of 0.1 to 25 N / 25 mm to the alkali- To 20 N / 25 mm. When the adhesive force is within the above-mentioned range, it is possible to prevent lifting, peeling, and the like from being adhered to an adherend such as a glass plate. The adhesive force referred to here is basically the adhesive force measured by the 180 ° pull-off method in accordance with JIS Z0237: 2009, but the measurement sample is set to have a width of 25 mm and a length of 100 mm, and the measurement sample is applied at 0.5 MPa, The sample is allowed to stand for 24 hours under the conditions of normal pressure, 23 DEG C and 50% RH, and then measured at a peeling rate of 300 mm / min.

The polarizing plate with a pressure-sensitive adhesive is preferably attached to the adherend and has an adhesive strength of 0.1 to 25 N / 25 mm, particularly 2 to 20 N / 25 mm, after standing for 2 days under normal pressure, 50 캜 and 50% RH. 25 mm. As described above, since the rise of the adhesive strength over time is suppressed, it can be evaluated that the reheat property is excellent. The adhesive force referred to here is basically the adhesive force measured by the 180 ° pull-off method in accordance with JIS Z0237: 2009, but the measurement sample is set to have a width of 25 mm and a length of 100 mm, and the measurement sample is applied to the adherend at 0.5 MPa, The test piece was attached by pressurizing at 50 ° C for 20 minutes and then allowed to stand at the above conditions (normal pressure, 50 ° C, 50% RH) for 2 days, and then measured at a peeling rate of 300 mm / min.

The embodiments described above are provided for the purpose of facilitating understanding of the present invention and are not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present 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.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Example 1]

1. Preparation of (meth) acrylic acid ester polymer

88 parts by mass of n-butyl acrylate, 5 parts by mass of methyl acrylate, 5 parts by mass of 2-phenylethyl acrylate, 2 parts by mass of 2-hydroxyethyl acrylate 2 , 200 parts by mass of ethyl acetate and 0.08 part by mass of 2,2'-azobisisobutyronitrile were placed, and the air in the reaction vessel was replaced with nitrogen gas. While stirring in the nitrogen atmosphere, the reaction solution was heated to 60 占 폚, allowed to react for 16 hours, and then cooled to room temperature. Here, a part of the obtained solution was measured for its molecular weight by the method described below to confirm the generation of the (meth) acrylic acid ester polymer (A) having a weight average molecular weight of 2,000,000.

2. Preparation of adhesive composition

100 parts by mass of the (meth) acrylic acid ester polymer (A) obtained in the above step (1) (solid content conversion value; hereinafter the same) and trimethylolpropane-modified xylene diisocyanate (manufactured by Mitsui Takeda Chemical Co., , 0.3 part by mass of a trade name " Takenate D110N ") and a silane coupling agent (C) having a mercapto group as a functional group reacting with an organic material were co-condensed with 3- 0.2 part by mass of water (trade name: " X41-1810 " manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.2 part by mass of di (acryloxyethyl) isocyanurate as an active energy ray- , 5 parts by mass of a mixture (trade name: Aronix M315, trade name, manufactured by Toako Seisai Co., Ltd.) and 1: 1 by mass of benzophenone and 1-hydroxycyclohexyl phenyl ketone as photopolymerization initiators (E) 0.5 part by mass (100 parts by mass of the above D component) (10 parts by mass with respect to 100 parts by mass of the D component) were mixed and thoroughly stirred and diluted with ethyl acetate to obtain a coating solution of the adhesive composition.

Table 1 shows the composition of the adhesive composition. Details of the abbreviations and the like in Table 1 are as follows.

[(Meth) acrylic acid ester polymer]

BA: n-butyl acrylate

MA: methyl acrylate

PhEA: 2-phenylethyl acrylate

HEA: 2-hydroxyethyl acrylate

4HBA: 4-hydroxybutyl acrylate

3. Preparation of Polarizer with Adhesive Layer

The coating solution of the obtained sticky composition was applied to a release treatment surface of a release sheet (SP-PET3811, thickness: 38 mu m) of a release sheet having one surface of a polyethylene terephthalate film peeled off with a silicone-based release agent using a knife coater, Lt; 0 > C for 1 minute to form a coating layer of the adhesive composition.

Then, a COP polarizing plate having a thickness of 100 占 퐉, which is protected with a triacetyl cellulose film on one side of the polarizer made of a polyvinyl alcohol film and protected with a cycloolefin polymer film on the other side, And the surface of the cycloolefin polymer film were in contact with each other. Thereafter, ultraviolet rays were irradiated onto the release sheet under the following conditions to obtain the pressure-sensitive adhesive layer, whereby a polarizer with a pressure-sensitive adhesive layer was obtained. The thickness of the pressure-sensitive adhesive layer was 20 占 퐉.

<Ultraviolet irradiation condition>

· Electrodeless lamp H valve used by Fusion

Illumination 600 mW / cm 2, light quantity 150 mJ / cm 2

· UV illuminance · "UVPF-36" manufactured by Eyegraphics is used for the photometer

[Examples 2 to 8 and Comparative Examples 1 to 3]

(B), the silane coupling agent (C), and the active energy (C) of the (meth) acrylic acid ester polymer (A), the weight average molecular weight of the (meth) acrylic acid ester polymer A polarizing plate with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1 except that the compounding amount of the ray-curable component (D) was changed as shown in Table 1. In Example 5, a sticking composition further comprising 2.3 parts by mass of a pyridinium salt based ionic liquid (trade name: &quot; IL-P18 &quot;, trade name; available from Koei Kagaku Co., Ltd.) as a nitrogen containing onium salt was used as an antistatic agent.

The weight average molecular weight (Mw) described above is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement Conditions>

GPC measurement apparatus: HLC-8020 manufactured by Tosoh Corporation

GPC column (passed in the following order): manufactured by Toso Co., Ltd.

  TSK guard column HXL-H

  TSK gel GMHXL (× 2)

  TSK gel G2000HXL

Measurement solvent: tetrahydrofuran

· Measuring temperature: 40 ℃

[Test Example 1] (Measurement of gel fraction)

(SP-PET3801 manufactured by LINTEC CORPORATION, thickness: 38 mu m) obtained by peeling one surface of a polyethylene terephthalate film with a silicone-based releasing agent was used in place of the polarizer used in the production of the polarizing plate with a pressure- , Thereby producing a pressure-sensitive adhesive sheet. Specifically, the release sheet was laminated on the pressure-sensitive adhesive layer on which the constitution comprising the release sheet / pressure-sensitive adhesive layer (thickness: 25 占 퐉) obtained in the manufacturing process of the example or the comparative example was exposed. Thus, a pressure-sensitive adhesive sheet having a configuration of a release sheet / pressure-sensitive adhesive layer / release sheet was produced.

The obtained pressure-sensitive adhesive sheet was cured for 7 days under conditions of 23 캜 and 50% RH. Thereafter, the pressure-sensitive adhesive sheet was sampled at a size of 80 mm x 80 mm, the pressure-sensitive adhesive layer was wrapped with a polyester mesh (mesh size 200), and the mass of the pressure-sensitive adhesive alone was weighed with a precision balance. The mass at this time is defined as M1.

Next, the pressure-sensitive adhesive wrapped in the polyester-made mesh was immersed in ethyl acetate at room temperature (23 DEG C) for 24 hours. Thereafter, the pressure-sensitive adhesive was taken out and air-dried for 24 hours under an environment of a temperature of 23 ° C and a relative humidity of 50%, and further dried in an oven at 80 ° C for 12 hours. The mass of the adhesive after drying was weighed with a precision balance. Let the mass at this time be M2. The gel fraction (%) is expressed by (M2 / M1) x100. The results are shown in Table 1.

[Test Example 2] (Measurement of haze value)

As a measurement sample, an adhesive sheet (cured for 7 days) similar to the adhesive sheet used for measuring the gel fraction was prepared. (%) Was measured in accordance with JIS K7136: 2000 using a haze meter (NDH2000, manufactured by Nippon Denshoku Chemical Co., Ltd.) for the pressure-sensitive adhesive layer (thickness: 25 탆) of the pressure-sensitive adhesive sheet. The results are shown in Table 1.

[Test Example 3] (Measurement of storage elastic modulus)

A pressure-sensitive adhesive sheet comprising a release sheet / pressure-sensitive adhesive layer / release sheet was produced in the same manner as in Test Example 1. The release sheet was peeled from the pressure-sensitive adhesive sheet, and a plurality of pressure-sensitive adhesive layers were laminated so as to have a thickness of 3 mm. A cylindrical body (height 3 mm) having a diameter of 8 mm was punched out from the obtained laminate of the pressure-sensitive adhesive layer, and this was used as a sample.

With respect to the sample, the storage elastic modulus (MPa) was measured by a twist shear method using a viscoelasticity measuring instrument (DYNAMIC ANALAYZER, manufactured by REOMETRIC Co., Ltd.) under the following conditions in accordance with JIS K7244-6. The results are shown in Table 1.

Measuring frequency: 1Hz

Measuring temperature: 23 DEG C, 80 DEG C

[Test Example 4] (Evaluation of durability)

The polarizer with a pressure-sensitive adhesive layer obtained in Examples and Comparative Examples was cut to produce a sample having a size of 233 mm 309 mm. As a sample, a prepared polarizing plate with a pressure-sensitive adhesive layer (pressure-sensitive adhesive layer formation) was stored for 7 days under an environment of 23 ° C and 50% RH. The release sheet was peeled off from the sample and attached to a non-alkali glass (Eagle XG manufactured by Corning) through the exposed pressure-sensitive adhesive layer, followed by pressurization at 0.5 MPa and 50 deg. C for 20 minutes in an autoclave made by Kurihara Seisakusho.

Thereafter, the mixture was placed under the conditions of the following durability conditions, and after 250 hours, a 10-fold magnifying glass was used to confirm whether or not the material was lifted or peeled off. The evaluation criteria are as follows. The results are shown in Table 1.

◎: No peeling or peeling was observed.

○: The size of peeling or peeling of 0.5 mm or less was confirmed.

X: The peeling or peeling of a size of 0.6 mm or more was confirmed.

&Lt; Durability condition &

· Drying at 80 ℃

· 60 ℃, relative humidity 90% RH

[Test Example 5] (Measurement of surface resistivity)

The polarizing plate with a pressure-sensitive adhesive layer obtained in Example 5 was cut into a size of 50 mm x 50 mm, and the obtained sample was left for 24 hours at a temperature of 23 캜 and a humidity of 50% RH. Thereafter, the surface resistance value (Ω / sq) was measured according to JIS K6911 using a resistivity meter (Hiresta UP MCP-HT450 type, manufactured by Mitsubishi Kagaku Analytec Co., Ltd.) against the surface of the adhesive layer exposed by peeling off the release sheet did. The results are shown in Table 1.

The surface resistance value is preferably 3.0 x 10 ¹¹ ? / Sq or less, more preferably 1.0 x 10 ¹¹ ? / Sq or less, and still more preferably 8.0 x 10 ¹⁰ ? / Sq or less. Since the surface resistance value is less than the above value, good antistatic property can be exhibited.

As can be seen from Table 1, the pressure-sensitive adhesive of the pressure-sensitive adhesive layer obtained in the examples is excellent in durability and has a good storage elastic modulus at 23 占 폚 and 80 占 폚.

The pressure-sensitive adhesive of the present invention is very suitable for bonding an optical member, particularly a polarizing plate, and the pressure-sensitive adhesive sheet of the present invention is very suitable for an optical member, in particular, a pressure-sensitive adhesive sheet for a polarizing plate.

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

Claims (16)

(Meth) acrylic acid ester polymer (A) containing, as a monomer unit constituting the polymer, at least 1.5 mass% of a monomer having a hydroxyl group,
An isocyanate-based cross-linking agent (B)
A silane coupling agent (C) having a mercapto group as a functional group reacting with an organic material,
An active energy ray-curable composition (D). The method according to claim 1,
Wherein the (meth) acrylic acid ester polymer (A) has a weight average molecular weight of 1,000 to 2,500,000 and 1.8 to 10% by mass of a monomer having a hydroxyl group as a monomer unit constituting the polymer . The method according to claim 1,
Wherein the (meth) acrylic acid ester polymer (A) further contains 1 to 10 mass% of a monomer having an aromatic ring as a monomer unit constituting the polymer. The method of claim 3,
Wherein the monomer having an aromatic ring is 2-phenylethyl (meth) acrylate. The method according to claim 1,
Wherein the (meth) acrylic acid ester polymer (A) does not contain a monomer having a carboxyl group as a monomer unit constituting the polymer. The method according to claim 1,
Wherein the isocyanate-based crosslinking agent (B) is trimethylolpropane-modified xylene diisocyanate. Wherein the active energy ray-curable component (D) is a polyfunctional acrylate-based monomer having a molecular weight of less than 1,000. 8. The method of claim 7,
Wherein the polyfunctional acrylate-based monomer has a cyclic structure. The method according to claim 1,
Wherein the content of the active energy ray-curable component (D) in the viscous composition is 5 to 20 parts by mass based on 100 parts by mass of the (meth) acrylic acid ester polymer (A). A pressure-sensitive adhesive which cures the pressure-sensitive adhesive composition according to any one of claims 1 to 9 by irradiation with active energy rays. 11. The method of claim 10,
Wherein the gel fraction after storage for 7 days under the environment of 23 占 폚 and 50% RH from the pressure-sensitive adhesive layer formation is 75 to 95%. 11. The method of claim 10,
(G ') at 23 ° C is 0.05 to 0.20 MPa, and a storage elastic modulus (G') at 80 ° C is 0.05 to 0.15 MPa. A pressure-sensitive adhesive sheet comprising a substrate and a pressure-sensitive adhesive layer,
Wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive according to claim 10. 14. The method of claim 13,
Wherein the substrate is an optical member. 15. The method of claim 14,
Wherein the optical member is a polarizing plate. Two release sheets,
And a pressure-sensitive adhesive layer sandwiched between the release sheets so as to contact the release surfaces of the two release sheets,
Wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive according to claim 10.

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