JP2014156551A - Pressure-sensitive adhesive composition, pressure-sensitive adhesive and pressure-sensitive adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive and a pressure-sensitive adhesive sheet showing excellent durability even when applied to an optical member such as a polarizing plate.SOLUTION: The pressure-sensitive adhesive composition comprises: a (meth)acrylate polymer (A) having a weight average molecular weight of 900000 to 3000000 and containing, as a monomer unit constituting the polymer, a monomer having an alicyclic structure; an active energy ray-curable component (B); and a silane coupling agent (C) having a mercapto group as a functional group to react with an organic material.

Description

  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 in particular, a pressure-sensitive adhesive composition suitable for optical members such as polarizing plates, a pressure-sensitive adhesive, and The present invention relates to an adhesive sheet.

  In recent years, in various electronic devices, a touch panel that serves as both a display device and an input unit is often used. The types of touch panels are mainly resistive film type, capacitance type, optical type and ultrasonic type. Resistance film type includes analog resistance film type and matrix resistance film type. There are types and projection types.

  As a touch panel in a mobile electronic device such as a smartphone or a tablet terminal that has been attracting attention recently, a projected capacitive type is often used. As a projected capacitive touch panel in such mobile electronic devices, for example, in order from the bottom, a liquid crystal display (LCD), an adhesive layer, a transparent conductive film (tin-doped indium oxide: ITO), a glass substrate, a transparent conductive film ( ITO) and a laminate of protective layers such as tempered glass have been proposed.

  A liquid crystal cell is generally used as an optical component constituting the liquid crystal display device. In general, the liquid crystal cell is arranged such that the alignment layers of the two transparent electrode substrates on which the alignment layers are formed are placed inside, with a predetermined interval by a spacer, and the periphery thereof is sealed to form the two transparent electrode substrates. A liquid crystal material is sandwiched between them. Usually, a polarizing plate is bonded to the outside of two transparent electrode substrates in a liquid crystal cell via an adhesive.

  As an adhesive used by a touch panel, what is shown by patent documents 1 is known, for example. This pressure-sensitive adhesive contains 0.2 to 20 parts by weight of a carboxyl group-containing monomer as a copolymer 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 a peroxide and 0.005 to 5 parts by weight of an epoxy crosslinking agent as a crosslinking agent with respect to 100 parts by weight of the (meth) acrylic polymer and (meth) acrylic polymer. Containing.

JP 2009-242786 A

  In the touch panel as described above, a polarizing plate using a polycycloolefin-based protective film has recently been increasingly used, and with the recent thinning of mobile electronic devices, the polarizing plate is also thin. It has become. However, since the polycycloolefin-based material has poor adhesion to the pressure-sensitive adhesive, and the thin polarizing plate has a high shrinkage rate, the conventional pressure-sensitive adhesive such as Patent Document 1 has low durability, and with time, Or there existed a problem that a float and peeling were easy to generate | occur | produce on high temperature conditions or wet heat conditions.

  The present invention has been made in view of such a situation, and an object thereof is to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive, and a pressure-sensitive adhesive sheet that are excellent in durability even when applied to an optical member such as a polarizing plate. To do.

  In order to achieve the above object, first, the present invention is a (meth) acryl having a weight average molecular weight of 900,000 to 3,000,000 and containing a monomer having an alicyclic structure as a monomer unit constituting the polymer. An adhesive comprising an acid ester polymer (A), an active energy ray-curable component (B), and a silane coupling agent (C) having a mercapto group as a functional group that reacts with an organic material. A composition is provided (Invention 1).

  When the pressure-sensitive adhesive composition according to the invention (Invention 1) is cured, a plurality of active energy ray-curable components (B) are bonded to each other to form a three-dimensional network structure. It is presumed that a structure in which a (meth) acrylic acid ester polymer (A) having a formula structure and a silane coupling agent (C) having a mercapto group are entangled is formed. The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition has excellent durability even when an optical member such as a polarizing plate, particularly a polycycloolefin-based optical member or a transparent conductive film is used as an adherend. It will be a thing.

  In the said invention (invention 1), it is preferable to contain a crosslinking agent (D) further (invention 2).

  In the said invention (invention 1 and 2), the said (meth) acrylic acid ester polymer (A) is 0.1-30 mass% of monomers which have the said alicyclic structure as a monomer unit which comprises the said polymer. It is preferable to contain (Invention 3).

  In the said invention (invention 1-3), it is preferable that the said alicyclic structure contains a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, or an isobornyl skeleton (invention 4).

  In the said invention (invention 1-4), the said (meth) acrylic acid ester polymer (A) contains 0.1-10 mass% of monomers which have a hydroxyl group further as a monomer unit which comprises the said polymer. Is preferred (Invention 5).

  In the said invention (invention 1-5), it is preferable that the said (meth) acrylic acid ester polymer (A) does not contain the monomer which has a carboxyl group substantially as a monomer unit which comprises the said polymer (invention). 6).

  In the said invention (invention 1-6), it is preferable that the said active energy ray hardening component (B) is a polyfunctional acrylate-type monomer with a molecular weight of less than 1000 (invention 7).

  In the said invention (invention 7), it is preferable that the said polyfunctional acrylate-type monomer has a cyclic structure (invention 8).

  In the said invention (invention 1-8), content of the said active energy ray hardening component (B) in the said adhesive composition is 100 mass parts of said (meth) acrylic acid ester polymers (A). 1 to 30 parts by mass (Invention 9).

  In the said invention (invention 1-9), content of the said silane coupling agent (C) in the said adhesive composition is 0 with respect to 100 mass parts of said (meth) acrylic acid ester polymers (A). It is preferably 0.01 to 5 parts by mass (Invention 10).

  In the said invention (invention 1-10), it is preferable that the said crosslinking agent (D) is an isocyanate type crosslinking agent (invention 11).

  In the said invention (invention 1-11), it is preferable to contain a photoinitiator (E) further (invention 12).

  2ndly, this invention provides the adhesive which hardens the said adhesive composition (invention 1-12) by irradiation of an active energy ray (invention 13).

  Thirdly, the present invention provides a pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer comprises the pressure-sensitive adhesive (invention 13) ( Invention 14).

  In the said invention (invention 14), it is preferable that the said base material is an optical member (invention 15).

  In the said invention (invention 15), it is preferable that the said optical member is a polarizing plate (invention 16).

  In the said invention (invention 15 and 16), it is preferable that the said optical member has a polycycloolefin type film (invention 17). “Having a polycycloolefin film” includes the concept of “consisting only of a polycycloolefin film”.

  Fourthly, the present invention is an adhesive sheet comprising two release sheets and an adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets. The pressure-sensitive adhesive sheet is characterized in that the layer is made of the pressure-sensitive adhesive (Invention 13) (Invention 18).

  When the pressure-sensitive adhesive composition according to the present invention contains the components (A) to (C), the resulting pressure-sensitive adhesive has high durability and is suitable for an optical member such as a polarizing plate.

It is sectional drawing of the adhesive sheet which concerns on the 1st Embodiment of this invention. It is sectional drawing of the adhesive sheet which concerns on the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
[Adhesive composition]
The pressure-sensitive adhesive composition according to this embodiment (hereinafter referred to as “pressure-sensitive adhesive composition P”) has a weight average molecular weight of 900,000 to 3,000,000 and has an alicyclic structure as a monomer unit constituting the polymer. A (meth) acrylic acid ester polymer (A) containing a monomer (alicyclic structure-containing monomer), an active energy ray-curable component (B), and a silane cup having a mercapto group as a functional group that reacts with an organic material A ring agent (C), and preferably further contains a crosslinking agent (D) and / or a photopolymerization initiator (E). In this specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms. Further, the “polymer” includes the concept of “copolymer”.

  When the adhesive composition P is cured, a plurality of active energy ray-curable components (B) are bonded to each other to form a three-dimensional network structure, and the three-dimensional network structure has an alicyclic structure (meta ) It is presumed that a structure in which the acrylate polymer (A) and the silane coupling agent (C) having a mercapto group are entangled is formed. The pressure-sensitive adhesive thus obtained is an optical member such as a polarizing plate, particularly a polycycloolefin-based optical member (for example, an optical member made of a polycycloolefin-based film, or an optical member having a polycycloolefin-based film in part). Member) or a transparent conductive film as an adherend, it is excellent in durability.

(1) (Meth) acrylic acid ester polymer (A)
The (meth) acrylic acid ester polymer (A) contains an alicyclic structure-containing monomer as a monomer unit constituting the polymer. Thereby, the obtained adhesive becomes excellent in durability as described above. This effect is considered to be due to the relatively strong affinity and interaction between the alicyclic structure and the optical member or the transparent conductive film, thereby improving the adhesion and the like.

  The alicyclic carbocycle may have a saturated structure or may have an unsaturated bond. The alicyclic structure may be a monocyclic alicyclic structure or a polycyclic alicyclic structure such as a bicyclic ring or a tricyclic ring. The alicyclic structure preferably has 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and more preferably 7 to 12 carbon atoms.

  Examples of the alicyclic structure include a cyclohexyl skeleton, dicyclopentadiene skeleton, adamantane skeleton, isobornyl skeleton, cycloalkane skeleton (cycloheptane skeleton, cyclooctane skeleton, cyclononane skeleton, cyclodecane skeleton, cycloundecane skeleton, cyclododecane skeleton, etc.) , Cycloalkene skeleton (cycloheptene skeleton, cyclooctene skeleton, etc.), norbornene skeleton, norbornadiene skeleton, polycyclic skeleton (cuban skeleton, basketetane skeleton, Hausan skeleton, etc.), spiro skeleton, etc. Those having a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton or an isobornyl skeleton, which exhibit the effect of improving durability.

  As the alicyclic structure-containing monomer, a (meth) acrylic acid ester monomer containing the above skeleton is preferable. Specifically, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, (meth) Examples thereof include adamantyl acrylate, isobornyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and the like. Preference is given to cyclohexyl acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate or isobornyl (meth) acrylate. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The (meth) acrylic acid ester polymer (A) preferably contains 0.1 to 30% by mass of the alicyclic structure-containing monomer as a monomer unit constituting the polymer, particularly 0.2 to The content is preferably 25% by mass, and more preferably 0.5 to 20% by mass. When the content of the alicyclic structure-containing monomer is less than 0.1% by mass, it is difficult to obtain the effect of improving the durability, and when the content of the alicyclic structure-containing monomer exceeds 30% by mass, the optical application As a result, preferable adhesiveness may not be obtained.

  The (meth) acrylic acid ester polymer (A) is an alkyl (meth) acrylate having 1 to 20 carbon atoms in addition to the alicyclic structure-containing monomer as a monomer unit constituting the polymer. It is preferable to contain an ester, and it is particularly preferable to contain an ester as a main component.

  The (meth) acrylic acid ester polymer (A) contains a (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group as a monomer unit constituting the polymer. Can be expressed. Examples of the (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid n-. Butyl, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, n-decyl (meth) acrylate, (meth) acrylic acid Examples include n-dodecyl, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. Among these, from the viewpoint of further improving the tackiness, (meth) acrylic acid esters having 1 to 8 carbon atoms in the alkyl group are preferable, and methyl (meth) acrylate and n-butyl (meth) acrylate are particularly 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) contains 20 to 99.8% by mass of (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms as the monomer unit constituting the polymer. In particular, it is preferably contained in an amount of 50 to 99.5% by mass, more preferably 60 to 99% by mass.

  Moreover, it is preferable that a (meth) acrylic acid ester polymer (A) contains the monomer (hydroxyl group containing monomer) which has a hydroxyl group as a monomer unit which comprises the said polymer. When the pressure-sensitive adhesive composition P contains a crosslinking agent (D), the hydroxyl group is highly reactive with the reactive functional group of the crosslinking agent (D), particularly the isocyanate group of the isocyanate-based crosslinking agent. The (meth) acrylic acid ester polymer (A) is effectively cross-linked by the cross-linking agent (D), and a good cross-linked structure is formed. Thereby, the obtained adhesive becomes more excellent in durability.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth ) (Meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate, and the like. Among them, the hydroxyl group in the resulting (meth) acrylic acid ester polymer (A). In view of reactivity with the crosslinking agent (B) and copolymerization with other monomers, 2-hydroxyethyl (meth) acrylate is preferred. These may be used alone or in combination of two or more.

  The (meth) acrylic acid ester polymer (A) preferably contains 0.1 to 10% by mass, particularly 0.2 to 8% by mass, of a hydroxyl group-containing monomer as a monomer unit constituting the polymer. It is preferable to contain 0.3 to 5% by mass. When the content of the hydroxyl group-containing monomer is in the above range, the formed crosslinked structure becomes favorable, and the resulting pressure-sensitive adhesive has more excellent durability. When the content of the hydroxyl group-containing monomer is less than 0.1% by mass, there are too few crosslinking points, and it is difficult to obtain an effect of improving durability. On the other hand, when the content of the hydroxyl group-containing monomer exceeds 10% by mass, there are too many crosslinking points, the resulting pressure-sensitive adhesive is not flexible, and the stress relaxation property may be lowered.

  It is preferable that the (meth) acrylic acid ester polymer (A) does not substantially contain a monomer having a carboxyl group (carboxyl group-containing monomer) as a monomer unit constituting the polymer. Even if the sticking target of the resulting pressure-sensitive adhesive is defective due to an acid, such as a transparent conductive film or a metal film, by containing substantially no monomer having a carboxyl group as an acid component, the acid It is possible to suppress those problems caused by. In particular, when the object to be pasted is a transparent conductive film, it is possible to suppress corrosion of the transparent conductive film or change of the resistance value of the transparent conductive film. Note that the silane coupling agent (C) described later works effectively even in such an acid-free system. Further, by substantially not containing a monomer having a carboxyl group, it is possible to prevent the carboxyl group from interfering with the reaction between the hydroxyl group of the hydroxyl group-containing monomer and the crosslinking agent (D), particularly the isocyanate crosslinking agent. it can.

  The (meth) acrylic acid ester polymer (A) may contain other monomers, if desired, in addition to the above monomers. As another monomer, the monomer (reactive functional group containing monomer) which has reactive functional groups other than a hydroxyl group may be sufficient, and a non-reactive monomer may be sufficient.

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

  Non-reactive monomers include, for example, methoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate, ethoxyethyl (meth) acrylate, etc. (meth) Acrylic acid esters, (meth) acrylic acid esters having an aromatic ring such as phenyl (meth) acrylate, non-crosslinkable acrylamides such as acrylamide and methacrylamide, (meth) acrylic acid N, N-dimethylaminoethyl, ( Examples include (meth) acrylic acid ester having a non-crosslinking tertiary amino group such as N, N-dimethylaminopropyl (meth) acrylate, vinyl acetate, styrene and the like. These may be used alone or in combination of two or more.

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

  The (meth) acrylic acid ester polymer (A) has a weight average molecular weight of 900,000 to 3,000,000, preferably 1,000,000 to 2,500,000, and particularly preferably 1.1 million to 2,000,000. In addition, the weight average molecular weight in this specification is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  When the weight average molecular weight of the (meth) acrylic acid ester polymer (A) is less than 900,000, the resulting pressure-sensitive adhesive is inferior in durability. Moreover, when the weight average molecular weight of (meth) acrylic acid ester polymer (A) exceeds 3 million, the adhesive force of the obtained adhesive will fall.

  In the adhesive composition P, the (meth) acrylic acid ester polymer (A) may be used singly or in combination of two or more. Moreover, the adhesive composition P may further contain a (meth) acrylic acid ester polymer that does not contain the alicyclic structure-containing monomer as a constituent monomer unit.

(2) Active energy ray-curable component (B)
The active energy ray-curable component (B) is not particularly limited as long as it is a component that is cured by irradiation with active energy rays without impeding the effects of the present invention, and may be any of a monomer, an oligomer, or a polymer. Or a mixture thereof. Among them, a polyfunctional acrylate monomer having a molecular weight of less than 1000 that is excellent in compatibility with the (meth) acrylic acid ester polymer (A) and the like can be preferably exemplified.

  Examples of polyfunctional acrylate monomers having a molecular weight of less than 1000 include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and polyethylene glycol diene. (Meth) acrylate, neopentyl glycol adipate di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, dicyclopentanyl di (meth) acrylate, caprolactone modified dicyclopentenyl di (meth) acrylate, ethylene oxide modified Bifunctional type such as di (meth) acrylate phosphate, di (acryloxyethyl) isocyanurate, allylated cyclohexyl di (meth) acrylate, etc .; trimethylolpropane tri (meth) acrylate , Dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) Trifunctional type such as isocyanurate; tetrafunctional type such as diglycerin tetra (meth) acrylate and pentaerythritol tetra (meth) acrylate; pentafunctional type such as propionic acid-modified dipentaerythritol penta (meth) acrylate; dipentaerythritol hexa Examples include hexafunctional types such as (meth) acrylate and caprolactone-modified dipentaerythritol hexa (meth) acrylate. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Among the polyfunctional acrylate monomers, those having a cyclic structure in the skeleton are preferable because of their superior durability performance. The cyclic structure may be a carbocyclic structure or a heterocyclic structure, and may be a monocyclic structure or a polycyclic structure. Examples of such polyfunctional acrylate monomers include those having an isocyanurate structure such as di (acryloxyethyl) isocyanurate, tris (acryloxyethyl) isocyanurate, dimethylol dicyclopentane diacrylate, ethylene oxide. Examples include modified hexahydrophthalic acid diacrylate, tricyclodecane dimethanol acrylate, adamantane diacrylate, and the like.

  As the active energy ray-curable component (B), an active energy ray-curable acrylate oligomer can also 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 is obtained by, for example, esterifying the hydroxyl group of a polyester oligomer having hydroxyl groups at both ends obtained by condensation of a polyvalent carboxylic acid and a polyhydric alcohol with (meth) acrylic acid. It can be obtained by esterifying the terminal hydroxyl group of an oligomer obtained by adding an alkylene oxide to a carboxylic acid 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 novolac type epoxy resin with (meth) acrylic acid for esterification. In addition, a carboxyl-modified epoxy acrylate oligomer obtained by partially modifying this epoxy acrylate oligomer with a dibasic carboxylic acid anhydride can also be used. The urethane acrylate oligomer can be obtained, for example, by esterifying a polyurethane oligomer obtained by a reaction between a polyether polyol or a polyester polyol and 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, particularly preferably 500 to 50,000, and more preferably 3,000 to 40,000. These acrylate oligomers may be used alone or in combination of two or more.

  Moreover, as the active energy ray-curable component (B), an adduct acrylate polymer in which a group having a (meth) acryloyl group is introduced into the side chain can also be used. Such an adduct acrylate-based polymer uses a copolymer of (meth) acrylic acid ester and a monomer having a crosslinkable functional group in the molecule, and a part of the crosslinkable functional group of the copolymer. , A (meth) acryloyl group and a compound having a group that reacts with a crosslinkable functional group can be reacted.

  The (meth) acrylic acid ester preferably contains a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, such as 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, isooctyl (meth) acrylate , Decyl (meth) acrylate, dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. 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 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 (meth) acrylate, ( (Meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl methacrylate and 4-hydroxybutyl (meth) acrylate; acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, Acrylamides such as N-methylol methacrylamide; monomethylaminoethyl (meth) acrylate, monoethylaminoethyl (meth) acrylate, monomethylaminopropyl (meth) acrylate, monoethylaminopropyl (meth) acrylate, etc. Meth) acrylic acid monoalkyl aminoalkyl, acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, ethylenically unsaturated carboxylic acids such as citraconic acid. These monomers may be used independently and may be used in combination of 2 or more type.

  Examples of the compound having a group that reacts with a (meth) acryloyl group and a crosslinkable functional group include 2-methacryloyloxyethyl isocyanate, 2- (0- [1′-methylpropylideneamino] carboxyamino) ethyl methacrylate, 2-[(3,5-dimethylpyrazolyl) carbonylamino] ethyl methacrylate, 1,1- (bisacryloyloxymethyl) ethyl isocyanate, 2-acryloyloxyethyl isocyanate, 2-acryloyloxyethyl succinate, 2-acryloyloxyethyl Preferred examples include hexahydrophthalimide, ω-carboxy-polycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and the like. These compounds may be used alone or in combination of two or more.

  The weight average molecular weight of the adduct acrylate polymer is preferably about 300,000 to 2,000,000, and particularly preferably about 500,000 to 850,000.

  The active energy ray-curable component (B) can be used by selecting one from among the above-mentioned polyfunctional acrylate monomers, acrylate oligomers and adduct acrylate polymers, or a combination of two or more. It can also be used in combination with other active energy ray-curable components.

  The content of the active energy ray-curable component (B) in the adhesive composition P is preferably 1 to 30 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A). In particular, the amount is preferably 2 to 20 parts by mass, and more preferably 3 to 9 parts by mass. The pressure-sensitive adhesive obtained from the pressure-sensitive adhesive composition P containing the active energy ray-curable component (B) within this range is presumed to form the aforementioned three-dimensional network structure satisfactorily.

(3) Silane coupling agent (C)
When the adhesive composition P contains a silane coupling agent (C) having a mercapto group as a functional group that reacts with an organic material, the reaction between the silane coupling agent (C) and the active energy ray-curable component (B). By the reaction between the silane coupling agent (C) and the adherend and the condensation reaction between the silane coupling agents (C), the effect of improving the adhesion is exhibited. In addition, the effect in case adhesive composition P contains a crosslinking agent (D) is mentioned later.

  The silane coupling agent (C) is an organosilicon compound having at least one mercapto group and at least one alkoxysilyl group in the molecule, has good compatibility with the pressure-sensitive adhesive component, and has light transmittance. Those having, for example, substantially transparent ones are preferred.

  Specific examples of the silane coupling agent (C) include mercapto group-containing low molecular silane coupling agents such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane; Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxy Examples include a mercapto group-containing oligomer type silane coupling agent such as a cocondensate with an alkyl group-containing silane compound such as silane. Among these, from the viewpoint of improving durability, a mercapto group-containing oligomer type silane coupling agent is preferable, and a cocondensate of a mercapto group-containing silane compound and an alkyl group-containing silane compound is particularly preferable, and 3-mercaptopropyltrimethoxy is more preferable. A cocondensate of silane and methyltriethoxysilane is preferred. These may be used individually by 1 type and may be used in combination of 2 or more type.

  The silane coupling agent (C) is preferably an oligomer. In the oligomeric silane coupling agent (C), the mercapto equivalent in the oligomer is preferably 100 to 1000 g / mol, particularly preferably 200 to 900 g / mol, and more preferably 300 to 700 g / mol. Preferably there is. If the mercapto equivalent is less than 100 g / mol, the effect of improving the durability may be reduced, and if it exceeds 1000 g / mol, there is a possibility that a decrease in adhesive strength or poor peeling occurs.

  The content of the silane coupling agent (C) in the adhesive composition P is preferably 0.01 to 5 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester polymer (A). In particular, it is preferably 0.02 to 3 parts by mass, and more preferably 0.05 to 2 parts by mass. When the content of the silane coupling agent (C) is less than 0.01 parts by mass, it is difficult to obtain the effect of the silane coupling agent (C). On the other hand, when content of a silane coupling agent (C) exceeds 5 mass parts, there exists a possibility that the extreme fall of adhesive force or the cohesion power shortage may generate | occur | produce.

(4) Crosslinking agent (D)
It is preferable that the adhesive composition P contains a crosslinking agent (D). Here, as described above, the silane coupling agent (C) contributes to the improvement of durability by the reaction with the active energy ray-curable component (B), its own condensation reaction, or the like. In addition to this, when the pressure-sensitive adhesive composition P contains a crosslinking agent (D), when the pressure-sensitive adhesive composition P is cured, the mercapto group of the silane coupling agent (C) It is presumed to react with a reactive functional group. In particular, when the crosslinking agent (D) is an isocyanate crosslinking agent, the mercapto group of the silane coupling agent (C) easily forms a thiourethane bond with the isocyanate group of the isocyanate crosslinking agent. On the other hand, another reactive functional group of the crosslinking agent (D) (isocyanate group of the isocyanate crosslinking agent) reacts with a reactive functional group (hydroxyl group, amino group, etc.) of the (meth) acrylic acid ester polymer (A). Then, the (meth) acrylic acid ester polymer (A) is crosslinked to form a second three-dimensional network structure. It is presumed that this second three-dimensional network structure is entangled with the above-described three-dimensional network structure based on the active energy ray-curable component (B) to form an integral three-dimensional network structure. With such a structure, the obtained pressure-sensitive adhesive is more excellent in durability. Further, the alkoxysilyl group of the silane coupling agent (C) is suspended from the (meth) acrylic acid ester polymer (A) at an appropriate distance from the (crosslinked) (meth) acrylic acid ester polymer (A). This provides an excellent coupling effect. The pressure-sensitive adhesive obtained as described above is excellent in adhesiveness, and is more excellent in durability even under high temperature conditions and wet heat conditions.

  When the crosslinking agent (D) is an isocyanate crosslinking agent, the mercapto group of the silane coupling agent (C) easily reacts with the isocyanate group of the isocyanate crosslinking agent, so that the (meth) acrylic acid ester polymer (A Even if the reactive functional group of () is only a hydroxyl group that is difficult to act with a general silane coupling agent, ((meth) acrylic acid ester polymer (A) does not contain a carboxyl group as a reactive functional group) Even if not, the coupling effect by the silane coupling agent (C) can be obtained.

  The crosslinking agent (D) may be any one having reactivity with the reactive functional group (hydroxyl group, amino group, etc.) of the (meth) acrylic acid ester polymer (A). Agent, epoxy crosslinking agent, amine crosslinking agent, melamine crosslinking agent, aziridine crosslinking agent, hydrazine crosslinking agent, aldehyde crosslinking agent, oxazoline crosslinking agent, metal alkoxide crosslinking agent, metal chelate crosslinking agent, metal A salt type crosslinking agent, an ammonium salt type crosslinking agent, etc. are mentioned. Among them, the isocyanate-based crosslinking agent is excellent in reactivity with the mercapto group possessed by the silane coupling agent (C), and when the (meth) acrylic acid ester polymer (A) has a hydroxyl group, There is an advantage of excellent reactivity. A crosslinking agent (D) can be used individually by 1 type or in combination of 2 or more types.

  The isocyanate-based crosslinking agent 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, alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, etc. And biuret bodies, isocyanurate bodies, and adduct bodies that are a reaction product with a low-molecular active hydrogen-containing compound such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, castor oil, and the like. Among them, trimethylolpropane-modified aromatic polyisocyanate from the viewpoint of reactivity with the hydroxyl group of (meth) acrylic acid ester polymer (A) In particular trimethylolpropane modified xylylene diisocyanate and trimethylolpropane-modified tolylene diisocyanate is preferable.

  It is preferable that content of the crosslinking agent (D) in the adhesive composition P is 0.05-3 mass parts with respect to 100 mass parts of (meth) acrylic acid ester polymer (A), especially 0. It is preferably 0.08 to 1.5 parts by mass, and more preferably 0.1 to 1 part by mass. The durability improvement effect by the said crosslinking agent (D) is acquired as content of a crosslinking agent (D) is 0.05 mass part or more. When content of a crosslinking agent (D) exceeds 3 mass parts, there exists a possibility that the degree of bridge | crosslinking may become excessive and the adhesive force of the adhesive obtained may fall.

(5) Photopolymerization initiator (E)
When ultraviolet rays are used as the active energy rays irradiated to the adhesive composition P, the adhesive composition P preferably further contains a photopolymerization initiator (E). By containing the photopolymerization initiator (E) in this way, the active energy ray-curable component (B) can be efficiently cured, and the polymerization curing time and the amount of active energy ray irradiation can be reduced. it can.

  Examples of such photopolymerization initiator (E) include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, and 2,2-dimethoxy. 2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4 -Diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone 2,4-diethylthioxanthone, benzyldimethyl ketal, acetophenone dimethyl ketal, p-dimethylaminobenzoate, oligo [2-hydroxy-2-methyl-1 [4- (1-methylvinyl) phenyl] propanone], 2 4,6-trimethylbenzoyl-diphenyl-phosphine oxide and the like. These may be used alone or in combination of two or more.

  It is preferable that a photoinitiator (E) is used in the quantity of the range of 2-15 mass parts with respect to 100 mass parts of active energy ray hardening components (B), especially 5-12 mass parts.

(6) Various additives For the adhesive composition P, various additives usually used in acrylic pressure-sensitive adhesives, for example, antistatic agents, tackifiers, antioxidants, ultraviolet absorbers, and light stabilizers are optionally used. An agent, a softening agent, a filler, a refractive index adjusting agent and the like can be added.

  Examples of the antistatic agent include ionic liquids, ionic solids, anionic surfactants, alkali metal salts, cationic surfactants, nonionic surfactants, and the like. It is preferable to use at least one selected from solid and alkali metal salts.

  As the ionic liquid and ionic solid, nitrogen-containing onium salts, sulfur-containing onium salts, phosphorus-containing onium salts and the like are preferable. Moreover, as an alkali metal salt, lithium salt, potassium salt, etc. are preferable. 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 0.5 to 8% by mass, and particularly preferably 1 to 5% by 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 becomes good.

[Method for producing adhesive composition]
The adhesive composition P was produced from the (meth) acrylic acid ester polymer (A), the (meth) acrylic acid ester polymer (A), the active energy ray-curable component (B), and the silane. While mixing with a coupling agent (C), if desired, it can manufacture by adding a crosslinking agent (D), a photoinitiator (E), an additive, etc. in arbitrary steps.

  The (meth) acrylic acid ester polymer (A) can be produced by polymerizing monomers constituting the polymer (in the case of a copolymer, a mixture of monomers) by an ordinary 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. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, and the like. Two or more kinds may be used in combination.

  Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more kinds may be used in combination. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane 1-carbonitrile), 2 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2′-azobis (2-methylpropionate) 4,4′-azobis (4-cyanovaleric acid), 2,2′-azobis (2-hydroxymethylpropionitrile), 2,2′-azobis [2- (2-imidazolin-2-yl) Propane] and the like.

  Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, and di (2-ethoxyethyl) peroxydi. Examples include carbonate, t-butyl peroxyneodecanoate, t-butyl peroxybivalate, (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.

  Once the (meth) acrylic acid ester polymer (A) is obtained, the solution of the (meth) acrylic acid ester polymer (A) is added to the active energy ray-curable component (B), the silane coupling agent (C) and the desired By adding a cross-linking agent (D), a photopolymerization initiator (E), an additive, and the like, and thoroughly mixing, an adhesive composition P (coating solution) diluted with a solvent is obtained.

  Examples of the dilution solvent for diluting the adhesive composition P to form a coating solution include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, methylene chloride, ethylene chloride, and the like. Halogenated hydrocarbons, methanol, ethanol, propanol, butanol, alcohols such as 1-methoxy-2-propanol, acetone, methyl ethyl ketone, ketones such as 2-pentanone, isophorone, cyclohexanone, esters such as ethyl acetate and butyl acetate, ethyl A cellosolv solvent such as cellosolve is used.

  The concentration / viscosity of the coating solution thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. For example, it dilutes so that the density | concentration of the adhesive composition P may be 10-40 mass%. In addition, when obtaining a coating solution, addition of a dilution solvent etc. is not a necessary condition, and if a viscosity etc. which can be coated with the adhesive composition P are not necessary, a dilution solvent does not need to be added. In this case, the adhesive composition P becomes the coating solution as it is.

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

  Although drying of the adhesive composition P may be performed by air drying, it is normally performed by heat processing (preferably hot air drying). When performing 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, particularly preferably 50 seconds to 2 minutes.

As active energy rays, ultraviolet rays, electron beams and the like are usually used. The dose of the active energy ray varies depending on the type of the energy ray, for example, in the case of ultraviolet rays, preferably 50~1000mJ / cm ² in quantity, in particular 100 to 500 mJ / cm ² is preferred. In the case of an electron beam, about 10 to 1000 krad is preferable.

  By drying the adhesive composition P and irradiating with active energy rays, the plural active energy ray-curable components (B) are bonded to each other to form a three-dimensional network structure. It is presumed that a structure in which the acrylate polymer (A) and the silane coupling agent (C) are entangled is formed.

  The pressure-sensitive adhesive obtained by curing the pressure-sensitive adhesive composition P has the above structure, the action of the alicyclic structure of the (meth) acrylic acid ester polymer (A), and the activity of the silane coupling agent (C). When an optical member such as a polarizing plate, particularly a polycycloolefin-based optical member or a transparent conductive film is used as an adherend due to the reaction with the energy ray-curable component (B) or its own condensation reaction. In addition, it is highly durable and exhibits excellent durability even under high temperature conditions and wet heat conditions.

  Moreover, when the adhesive composition P contains a crosslinking agent (D), the (meth) acrylic acid ester polymer (A) is crosslinked by the crosslinking agent (D) by the above heat treatment, and the second tertiary It is presumed that an original three-dimensional network structure is also formed and entangled with the three-dimensional network structure of the active energy ray-curable component (B) to form an integral three-dimensional network structure. The mercapto group of the silane coupling agent (C) reacts with the reactive functional group of the crosslinking agent (D), and the alkoxysilyl group of the silane coupling agent (C) passes through the crosslinking agent (D). The (meth) acrylic acid ester polymer (A) and by extension, present at an appropriate distance from the above three-dimensional network structure, exhibit an excellent coupling effect. The pressure-sensitive adhesive thus obtained is excellent in adhesiveness, and is more excellent in durability even under high temperature conditions and wet heat conditions. For example, even when kept under a high temperature condition of 85 ° C. or a wet heat condition of 60 ° C./90% RH for 500 hours, the occurrence of floating, peeling, bubbles, etc. is prevented / suppressed.

  The gel fraction of the pressure-sensitive adhesive according to this embodiment is preferably 30 to 99%, particularly preferably 40 to 95%, and further preferably 50 to 90%. When the gel fraction is less than 30%, the cohesive force of the pressure-sensitive adhesive is insufficient, and durability and reworkability may be deteriorated. On the other hand, if the gel fraction exceeds 99%, the adhesive strength may be too low and the durability may be lowered. In addition, the said gel fraction is a value after storing for 7 days in 23 degreeC and 50% RH environment after adhesive layer formation (after a curing period progress). If it is unclear whether the curing period has elapsed, after storing again for 7 days in an environment of 23 ° C. and 50% RH, the gel fraction should be within the above range.

[Adhesive sheet]
As shown in FIG. 1, the pressure-sensitive adhesive sheet 1 </ b> A according to the first embodiment is laminated on the pressure-sensitive adhesive layer 11, the pressure-sensitive adhesive layer 11 stacked on the release surface of the release sheet 12, and the pressure-sensitive adhesive layer 11. And the formed base material 13.

  In addition, as shown in FIG. 2, the adhesive sheet 1B according to the second embodiment includes the two release sheets 12a and 12b and the two release sheets 12a and 12b so as to be in contact with the release surfaces of the two release sheets 12a and 12b. And the pressure-sensitive adhesive layer 11 sandwiched between the release sheets 12a and 12b. In addition, the release surface of the release sheet in this specification refers to a surface having peelability in the release sheet, and includes both a surface that has been subjected to a release treatment and a surface that exhibits peelability without being subjected to a release treatment. .

  In any of the pressure-sensitive adhesive sheets 1A and 1B, the pressure-sensitive adhesive layer 11 is made of a pressure-sensitive adhesive formed by curing the above-described pressure-sensitive adhesive composition.

  The thickness of the pressure-sensitive adhesive layer 11 is appropriately determined according to the purpose of use of the pressure-sensitive adhesive sheets 1A and 1B, but is usually in the range of 5 to 100 μm, preferably 10 to 60 μm, for example, for optical members, particularly for polarizing plates. When used as an adhesive layer, it is preferably 10 to 50 μm, particularly preferably 15 to 30 μm.

  There is no restriction | limiting in particular as the base material 13, What was used as a base material sheet of a normal adhesive sheet can be used. For example, in addition to the desired optical member, woven or non-woven fabric using fibers such as rayon, acrylic, polyester, etc .; synthetic paper; paper such as fine paper, glassine paper, impregnated paper, coated paper; metal such as aluminum and copper Foil; Foam such as urethane foam and polyethylene foam; Polyester film such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyurethane film, polyethylene film, polypropylene film, cellulose film such as triacetyl cellulose, polyvinyl chloride film , Polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate copolymer film, polystyrene film, polycarbonate film, acrylic resin film, norbornene resin film, cycloolefin Plastic film such as emission resin film; and the like of two or more kinds of those laminates. The plastic film may be uniaxially stretched or biaxially stretched.

  Examples of the optical member include a polarizing plate (polarizing film), a polarizer, a retardation plate (retarding film), a viewing angle compensation film, a brightness enhancement film, a contrast enhancement film, a liquid crystal polymer film, a diffusion film, and a transflective film. Etc. Among them, the polarizing plate is preferable as a base material for forming the pressure-sensitive adhesive (the pressure-sensitive adhesive layer 11) according to the present embodiment from the viewpoint of durability because it easily contracts and has a large dimensional change. In particular, a polarizing plate in which one of the protective films is a polycycloolefin-based film (hereinafter sometimes referred to as “COP polarizing plate”) is easily shrunk, has a large dimensional change, has a large contact angle, and has a close contact. From the viewpoint of durability, it is more preferable as a base material for forming the pressure-sensitive adhesive according to the present embodiment (the pressure-sensitive adhesive layer 11).

  Although the thickness of the base material 13 changes with kinds, for example in the case of an optical member, it is 10-500 micrometers normally, Preferably it is 50-300 micrometers, Most preferably, it is 80-150 micrometers.

  As the release sheets 12, 12a, 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 A fluororesin film or the like is used. These crosslinked films are also used. Furthermore, these laminated films may be sufficient. In addition, it is preferable that the release sheets 12, 12a, and 12b are active energy ray permeable.

  The release surface of the release sheet (particularly the surface in contact with the pressure-sensitive adhesive layer 11) is preferably subjected to a release treatment. Examples of the release agent used for the release treatment include alkyd, silicone, fluorine, unsaturated polyester, polyolefin, and wax release agents.

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

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

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

  Moreover, it replaces with forming an adhesive layer 11 by irradiating an active energy ray through a peeling sheet as mentioned above, and forms the coating-film layer of the adhesive composition P on a peeling sheet, The coating-film layer With the exposed state, the active energy ray may be irradiated to form the pressure-sensitive adhesive layer 11, and then a base material or a release sheet may be laminated on the pressure-sensitive adhesive layer 11. Furthermore, the adhesive layer 11 may be formed by directly forming a coating layer of the adhesive composition P on the substrate and irradiating the coating layer with active energy rays.

  As a method for 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, or the like can be used.

  Here, for example, to manufacture a liquid crystal display device composed of a liquid crystal cell and a polarizing plate, 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-sensitive adhesive sheet 1A is peeled off. What is necessary is just to bond the exposed adhesive layer 11 and a liquid crystal cell.

  For example, in order to manufacture a liquid crystal display device in which a retardation plate is disposed between a liquid crystal cell and a polarizing plate, as an example, first, one release sheet 12a (or 12b) of the adhesive sheet 1B is released. Then, the pressure-sensitive adhesive layer 11 exposed from the pressure-sensitive adhesive sheet 1B and the phase difference plate are bonded together. Next, the release sheet 12 of the pressure-sensitive adhesive sheet 1A using a polarizing plate as the base material 13 is peeled off, and the pressure-sensitive adhesive layer 11 exposed from the pressure-sensitive adhesive sheet 1A and the retardation plate are bonded. Furthermore, 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 exposed from the pressure-sensitive adhesive sheet B is bonded to the liquid crystal cell.

  According to the above pressure-sensitive adhesive sheets 1A and 1B, since the pressure-sensitive adhesive layer 11 is excellent in durability, it floats and peels between the substrate 13 such as the COP polarizing plate and the adherend even under high temperature conditions or wet heat conditions. , Foaming and the like are prevented / suppressed.

  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 2.0% or less, particularly 1.8% or less. It is preferable that it is 1.0% or less. When the haze value is 1.0% or less, the transparency is very high, which is suitable for optical applications.

  On the other hand, the pressure-sensitive adhesive sheets 1A and 1B according to the present embodiment preferably have a transparent conductive film as an adherend. In this case, it is preferable that the (meth) acrylic acid ester polymer (A) in the adhesive composition P does not contain a carboxyl group-containing monomer as a monomer unit constituting the polymer. Thereby, it can suppress that the negative influence by an acid component is given to a transparent conductive film. Specifically, corrosion of the transparent conductive film or change in the resistance value of the transparent conductive film can be suppressed.

  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, tin-doped indium oxide (ITO), and zinc oxide-doped oxide. Examples include composite oxides such as indium, fluorine-doped indium oxide, antimony-doped tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide, and non-oxidized compounds such as chalcogenide, lanthanum hexaboride, titanium nitride, and titanium carbide. It is done.

  Further, the pressure-sensitive adhesive sheet 1A using a polarizing plate as the base material 13 (hereinafter sometimes referred to as “polarizing plate with a pressure-sensitive adhesive layer”) has an adhesive strength to non-alkali glass of 0.1 to 25 N / 25 mm. In particular, it is preferably 2 to 20 N / 25 mm. When the adhesive strength is within the above range, it is possible to prevent floating or peeling between the glass plate and the adherend. In addition, although the adhesive force here means the adhesive force measured by the 180 degree peeling method according to JIS Z0237: 2009, the measurement sample has a width of 25 mm and a length of 100 mm, and the measurement sample is attached. After pressing and pasting the body (non-alkali glass) at 0.5 MPa and 50 ° C. for 20 minutes, it was left for 24 hours under conditions of normal pressure, 23 ° C. and 50% RH, and then the peeling speed was 300 mm / min. Shall be measured.

  Further, the polarizing plate with the pressure-sensitive adhesive layer is preferably 0.5 to 30 N / 25 mm in adhesive strength after being pasted on the alkali-free glass and allowed to stand for 14 days (adhesive strength after 14 days of pasting). In particular, 1 to 25 N / 25 mm is preferable, and 2 to 20 N / 25 mm is more preferable. Thus, by suppressing the increase in adhesive strength over time, the polarizing plate with the pressure-sensitive adhesive layer can be evaluated as having excellent reworkability. The adhesive strength here also means the adhesive strength measured by a 180 ° peeling method in accordance with JIS Z0237: 2009. The measurement sample is 25 mm wide and 100 mm long, and the measurement sample is attached to the adherend. (Applicable to alkali-free glass) with a pressure of 0.5 MPa and 50 ° C. for 20 minutes, and then left for 14 days under conditions of normal pressure, 23 ° C. and 50% RH, then at a peeling speed of 300 mm / min. Shall be measured.

  The embodiment described above is described for facilitating understanding of the present invention, and is 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 adhesive sheet 1A may be omitted, or one of the release sheets 12a and 12b in the 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 etc.

[Example 1]
1. Preparation of (meth) acrylic acid ester polymer In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device and nitrogen introduction tube, 74 parts by mass of n-butyl acrylate, 5 parts by mass of methyl acrylate, acrylic acid 20 parts by mass of isobornyl, 1 part by mass of 2-hydroxyethyl acrylate, 200 parts by mass of ethyl acetate, and 0.08 part by mass of 2,2′-azobisisobutyronitrile are charged, and the air in the reaction vessel is nitrogen gas Replaced with. While stirring in 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 of a part of the obtained solution was measured by a method described later, and production of a (meth) acrylic acid ester polymer (A) having a weight average molecular weight (Mw) of 18.5 million was confirmed.

2. Preparation of adhesive composition As (meth) acrylic acid ester polymer (A) 100 mass parts (solid content conversion value; same hereafter) obtained by the said process (1), and active energy ray hardening component (B) Silane cup having 5 parts by mass of tris (acryloxyethyl) isocyanurate (manufactured by Toa Gosei Co., Ltd., trade name “Aronix M-315”, molecular weight: 423, trifunctional type) and a mercapto group as a functional group that reacts with an organic material As a ring agent (C), 0.3 part by mass of a co-condensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X41-1810”), and as a crosslinking agent (D) 0.4 parts by mass of trimethylolpropane-modified xylylene diisocyanate (manufactured by Soken Chemical Co., Ltd., trade name “TD-75”) and benzoate as a photopolymerization initiator (E) 0.5 parts by mass of phenone and 1-hydroxycyclohexyl phenyl ketone mixed at a mass ratio of 1: 1 (Ciba Specialty Chemicals Co., Ltd., Irgacure 500) are mixed, stirred well, and diluted with ethyl acetate By doing this, the coating solution of the adhesive composition was obtained.

Here, Table 1 shows the composition of the adhesive composition. Details of the abbreviations and the like described in Table 1 are as follows.
[(Meth) acrylic acid ester polymer (A)]
BA: n-butyl acrylate MA: methyl acrylate HEA: 2-hydroxyethyl acrylate IBXA: isobornyl acrylate ADMMA: adamantyl methacrylate DCPA: dicyclopentanyl acrylate CHA: cyclohexyl acrylate PhEA: 2-phenoxy acrylate Ethyl AA: Acrylic acid [Silane coupling agent (C)]
C1: Co-condensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “X41-1810”, mercapto equivalent: 450 g / mol)
C2: 3-mercaptopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-803”)
C3: 3-glycidoxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”)
[Crosslinking agent (D)]
XDI: trimethylolpropane-modified xylylene diisocyanate (manufactured by Soken Chemical Co., Ltd., trade name “TD-75”)
TDI: Trimethylolpropane modified tolylene diisocyanate (manufactured by Soken Chemical Co., Ltd., trade name “L-45”)

3. Production of polarizing plate with pressure-sensitive adhesive layer A release sheet (SP-PET3811, manufactured by Lintec Corporation, thickness: 38 μm) obtained by subjecting one surface of a polyethylene terephthalate film to a release treatment with a silicone-based release agent. After the coating was applied to the release-treated surface with a knife coater, the coating layer of the adhesive composition was formed by heat treatment at 90 ° C. for 1 minute.

Next, a COP polarizing plate having a thickness of 100 μm formed by protecting one surface of a polarizer made of a polyvinyl alcohol film with a triacetyl cellulose film and the other surface with a cycloolefin polymer film is exposed to the coating layer. Bonded to the surface side. Then, the polarizing plate with an adhesive layer was obtained by irradiating an ultraviolet-ray on the following conditions through a peeling sheet, and making the said coating-film layer into an adhesive layer. In addition, the thickness of the adhesive layer was 20 μm.
<Ultraviolet irradiation conditions>
Fusion Co. electrodeless lamp H bulb used, illuminance 600 mW / cm ^2, light quantity 150 mJ / cm ²
・ Use UV-illumination meter "UVPF-36" manufactured by iGraphics.

[Examples 2 to 22, Comparative Examples 1 to 5]
Kind and ratio of each monomer constituting (meth) acrylate polymer (A), weight average molecular weight of (meth) acrylate polymer (A), active energy ray-curable component (B), silane cup A polarizing plate with an adhesive layer in the same manner as in Example 1 except that the type and / or blending amount of the ring agent (C), the crosslinking agent (D) and the photopolymerization initiator (E) are changed as shown in Table 1. Manufactured. In Example 7, a pressure-sensitive adhesive composition further blended with a pyridinium salt ionic liquid (manufactured by Guangei Chemical Co., Ltd., trade name “IL-P18”) as an antistatic agent was used.

Here, the above-mentioned weight average molecular weight (Mw) is a polystyrene-reduced weight average molecular weight measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC).
<Measurement conditions>
GPC measurement device: manufactured by Tosoh Corporation, HLC-8020
GPC column (passed in the following order): TSK guard column HXL-H manufactured by Tosoh Corporation
TSK gel GMHXL (× 2)
TSK gel G2000HXL
・ Measurement solvent: Tetrahydrofuran ・ Measurement temperature: 40 ° C.

[Test Example 1] (Measurement of gel fraction)
Instead of the polarizing plate used for the production of the polarizing plate with the pressure-sensitive adhesive layer in the examples or comparative examples, a release sheet obtained by peeling one side of the polyethylene terephthalate film with a silicone release agent (manufactured by Lintec Corporation, SP-PET 3801, thickness) S: 38 μm) was used to prepare an adhesive sheet. Specifically, the release sheet is peeled onto the exposed pressure-sensitive adhesive layer of the structure composed of the release sheet / pressure-sensitive adhesive layer (thickness: 20 μm) obtained in the production process of the examples or comparative examples. The layers were laminated so that the surface side was in contact. Thereby, the adhesive sheet which consists of a structure of a peeling sheet / adhesive layer / release sheet was produced.

  The obtained pressure-sensitive adhesive sheet was cured for 7 days under the conditions of 23 ° C. and 50% RH. Thereafter, the pressure-sensitive adhesive sheet was sampled to a size of 80 mm × 80 mm, the pressure-sensitive adhesive layer was wrapped in 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 M1.

  Next, the pressure-sensitive adhesive wrapped in the polyester mesh was immersed in ethyl acetate at room temperature (23 ° C.) for 24 hours. Thereafter, the pressure-sensitive adhesive was taken out, air-dried for 24 hours in 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 only the pressure-sensitive adhesive after drying was weighed with a precision balance. The mass at this time is M2. The gel fraction (%) is represented by (M2 / M1) × 100. The results are shown in Table 2.

[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. About the adhesive layer (thickness: 20 micrometers) of the said adhesive sheet, haze value (%) was measured according to JISK7136: 2000 using the haze meter (Nippon Denshoku Industries Co., Ltd. make, NDH2000). The results are shown in Table 2.

[Test Example 3] (Measurement of adhesive strength)
The pressure-sensitive adhesive layer-attached polarizing plate obtained in Examples or Comparative Examples was cut to prepare samples having a width of 25 mm and a length of 100 mm. After peeling the release sheet from this sample and pasting the sample on alkali-free glass (Corning, Eagle XG) through the exposed adhesive layer, 0.5 MPa at 50 ° C. in an autoclave manufactured by Kurihara Seisakusho, Pressurized for 20 minutes. Then, after leaving for 24 hours (1 day) or 14 days under conditions of 23 ° C. and 50% RH, using a tensile tester (Orientec Co., Tensilon), the peeling speed according to JIS Z0237: 2009 The adhesive strength (adhesive strength after 1 day and 14 days after application; N / 25 mm) was measured under the conditions of 300 mm / min and a peeling angle of 180 °. The results are shown in Table 2, respectively.

[Test Example 4] (Durability evaluation)
The pressure-sensitive adhesive layer-attached polarizing plate obtained in Examples or Comparative Examples was cut to produce a sample having a size of 233 mm × 309 mm. As a sample, a sample after storage for 7 days in an environment of 23 ° C. and 50% RH was prepared from preparation of a polarizing plate with an adhesive layer (adhesive layer formation). The release sheet is peeled off from this sample and attached to an alkali-free glass (Corning Corp., Eagle XG) through the exposed adhesive layer, and then applied at 0.5 MPa and 50 ° C. for 20 minutes in an autoclave manufactured by Kurihara Seisakusho. Pressed.

Then, it put into the environment of the following durable conditions, and the presence or absence of the float and peeling was confirmed using the 10 time loupe after 500 hours. The evaluation criteria are as follows. The results are shown in Table 2.
A: No lifting or peeling was confirmed.
○: Lifting or peeling of a size of 0.5 mm or less was confirmed.
X: Floating or peeling of a size of 0.6 mm or more was confirmed.
<Durability conditions>
・ 85 ℃ dry
・ 60 ℃, relative humidity 90% RH

  As can be seen from Table 2, the pressure-sensitive adhesive of the pressure-sensitive adhesive layer obtained in the examples had high adhesive strength and was excellent in durability.

  The pressure-sensitive adhesive of the present invention is suitable for adhesion of optical members, particularly polarizing plates, and the pressure-sensitive adhesive sheet of the present invention is suitable as a pressure-sensitive adhesive sheet for optical members, particularly for polarizing plates.

1A, 1B ... Adhesive sheet 11 ... Adhesive layer 12, 12a, 12b ... Release sheet 13 ... Base material

Claims (18)

(Meth) acrylic acid ester polymer (A) having a weight average molecular weight of 900,000 to 3,000,000 and containing a monomer having an alicyclic structure as a monomer unit constituting the polymer;
An active energy ray-curable component (B);
A pressure-sensitive adhesive composition comprising a silane coupling agent (C) having a mercapto group as a functional group that reacts with an organic material.   Furthermore, a crosslinking agent (D) is contained, The adhesive composition of Claim 1 characterized by the above-mentioned.   The said (meth) acrylic acid ester polymer (A) contains 0.1-30 mass% of monomers which have the said alicyclic structure as a monomer unit which comprises the said polymer. Or the adhesive composition of 2.   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the alicyclic structure includes a cyclohexyl skeleton, a dicyclopentadiene skeleton, an adamantane skeleton, or an isobornyl skeleton.   The said (meth) acrylic acid ester polymer (A) contains 0.1-10 mass% of monomers which further have a hydroxyl group as a monomer unit which comprises the said polymer. The adhesive composition as described in any one of Claims.   The said (meth) acrylic acid ester polymer (A) does not contain the monomer which has a carboxyl group substantially as a monomer unit which comprises the said polymer, The any one of Claims 1-5 characterized by the above-mentioned. The adhesive composition according to 1.   The adhesive composition according to any one of claims 1 to 6, wherein the active energy ray-curable component (B) is a polyfunctional acrylate monomer having a molecular weight of less than 1000.   The pressure-sensitive adhesive composition according to claim 7, wherein the polyfunctional acrylate monomer has a cyclic structure.   Content of the said active energy ray hardening component (B) in the said adhesive composition is 1-30 mass parts with respect to 100 mass parts of said (meth) acrylic acid ester polymers (A). The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein   Content of the said silane coupling agent (C) in the said adhesive composition is 0.01-5 mass parts with respect to 100 mass parts of said (meth) acrylic acid ester polymers (A). The pressure-sensitive adhesive composition according to any one of claims 1 to 9, wherein   The said crosslinking agent (D) is an isocyanate type crosslinking agent, The adhesive composition as described in any one of Claims 2-10 characterized by the above-mentioned.   Furthermore, a photoinitiator (E) is contained, The adhesive composition as described in any one of Claims 1-11 characterized by the above-mentioned.   The adhesive which hardens the adhesive composition as described in any one of Claims 1-12 by irradiation of an active energy ray. A pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer,
The said adhesive layer consists of an adhesive of Claim 13, The adhesive sheet characterized by the above-mentioned.   The pressure-sensitive adhesive sheet according to claim 14, wherein the base material is an optical member.   The pressure-sensitive adhesive sheet according to claim 15, wherein the optical member is a polarizing plate.   The pressure-sensitive adhesive sheet according to claim 15 or 16, wherein the optical member has a polycycloolefin-based film. Two release sheets,
An adhesive sheet comprising an adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets,
The said adhesive layer consists of an adhesive of Claim 13, The adhesive sheet characterized by the above-mentioned.

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