JP5545416B2 - Adhesive, adhesive sheet and optical laminate - Google Patents

Description

  The present invention relates to an acrylic pressure-sensitive adhesive and a pressure-sensitive adhesive sheet excellent in unevenness followability. Moreover, this invention relates also to the optical laminated body manufactured using these.

  An acrylic pressure-sensitive adhesive mainly composed of an acrylic polymer and a pressure-sensitive adhesive sheet formed using an acrylic pressure-sensitive adhesive are widely used for bonding various articles such as plastic films and panels. In recent years, articles to be bonded have become more diversified, and demands for properties at the time of bonding and after bonding have become more severe as industrial products have become more sophisticated and complicated. For this reason, various attempts have been made to improve the performance as a pressure-sensitive adhesive by adding an additive to the acrylic pressure-sensitive adhesive.

  For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2005-255877) includes an acrylic having a cyclic structure containing 3 to 10% by weight of a carboxyl group-containing crosslinkable monomer unit and having a weight average molecular weight of 3000 to 6000. It is described that a pressure-sensitive adhesive in which a polymerization oligomer is added to an acrylic polymer or a crosslinking agent as a main component has high transparency after bonding, and can prevent floating, peeling and warping.

  Patent Document 2 (Japanese Patent Publication No. 2009-215522) includes 1 to 10% by weight of a carboxyl group-containing crosslinkable monomer unit, and an acrylic having a cyclic structure with a weight average molecular weight of 3000 to 6000. A pressure-sensitive adhesive sheet with a specific thickness unevenness using a polymer oligomer added to an acrylic polymer or cross-linking agent as a main component is used for the transparency, adhesion, and foam resistance after bonding. It is described that it has excellent properties and the thickness unevenness of the pressure-sensitive adhesive layer is small.

  Furthermore, Patent Document 3 (Japanese Patent Application Laid-Open No. 2011-157458) includes an acrylic polymerized oligomer containing 1 to 10% by weight of a carboxyl group-containing crosslinkable monomer unit and having a weight average molecular weight of 3000 to 10,000. The adhesive added to the acrylic polymer and cross-linking agent, which is the main component, does not generate voids on the end face when applied to uneven parts or thick printed layers, and has followability to steps, and is durable. It is described that the adhesiveness is also high.

  Patent Document 4 (Japanese Patent No. 3272721) is formed by using a pressure-sensitive adhesive in which a liquid resin such as process oil, liquid polyether, or liquid polyterpene is added to an acrylic polymer or a crosslinking agent as a main component. It is described that the pressure-sensitive adhesive layer has appropriate elasticity and flexibility and can absorb the shrinkage stress of the substrate.

  Further, Patent Document 5 (Japanese Patent Laid-Open No. 2002-047468), Patent Document 6 (Japanese Patent Laid-Open No. 2002-129123) and Patent Document 7 (Japanese Patent Laid-Open No. 2003-049141) include a carboxyl group and / or a hydroxy group. A copolymer having a controlled molecular weight obtained by copolymerizing 0.2 to 10% by weight of the crosslinkable monomer with 90 to 99.8% by weight of a (meth) acrylic acid alkyl ester monomer, and Mw / Mn is A low molecular weight non-functional acrylic polymer of 1.0 to 2.5 and a pressure-sensitive adhesive containing a cross-linking agent exhibit excellent pressure-sensitive adhesiveness even under high temperature and high humidity conditions, and foaming and peeling due to dimensional changes do not occur. And the like.

JP 2005-255877 A Special table 2009-215522 JP 2011-157458 A Japanese Patent No. 3272721 JP 2002-047468 A JP 2002-129123 A JP 2003-049141 A

The acrylic pressure-sensitive adhesive described in these patent documents can exhibit a desired function when applied and bonded onto a surface having a smooth flat surface. However, when applied to a surface having irregularities, the adhesive cannot sufficiently follow the irregularities, and bubbles remain in the concave portions, which causes a decrease in adhesive force, adhesive holding force and transparency. There is. In recent years, there has been an increasing opportunity to apply an adhesive to a surface intentionally provided with unevenness by printing, etching, or the like, and it is necessary to provide an adhesive that does not have such a problem. In addition, since it is also required to be applied to display panels, etc., we provide adhesives with sufficient durability so that the transparency and color after bonding are maintained even under high temperature and high humidity conditions. There is also a need to do.
Accordingly, the present inventors have attempted to develop a pressure-sensitive adhesive that solves such technical problems. That is, the present inventors have intensively studied for the purpose of providing a pressure-sensitive adhesive having excellent unevenness followability, high adhesive strength and adhesive retention, and excellent high temperature and high humidity durability.

The inventors of the present invention made a new pressure-sensitive adhesive by adding oligomers and additives having various functional groups to the acrylic polymer, and repeated tests. However, it has not been easy to find a pressure-sensitive adhesive that has excellent unevenness followability, high adhesive strength and adhesive retention, and excellent high-temperature and high-humidity durability.
The inventors of the present invention have found that a pressure-sensitive adhesive that solves the above problems can be provided by adding a non-functional acrylic polymer that satisfies a specific condition after repeated trial and error. The present invention has been provided based on such knowledge, and includes the following configurations.

[1] A pressure-sensitive adhesive comprising a crosslinkable acrylic polymer as a main component, and a crosslinking agent and a non-functional acrylic polymer having a weight average molecular weight of 1000 to 5000 and Tg of 0 ° C. or less. Agent.
[2] The pressure-sensitive adhesive according to [1], wherein the non-functional acrylic polymer has a viscosity at 25 ° C. of 4800 mPa · s or less.
[3] The pressure-sensitive adhesive according to [1] or [2], wherein the crosslinkable acrylic polymer has a weight average molecular weight of 100,000 to 2,000,000.
[4] The pressure-sensitive adhesive according to [3], wherein the crosslinkable acrylic polymer is polymerized using a polymerization initiator having no repeating unit, and has a weight average molecular weight of 350,000 to 750,000.
[5] The pressure-sensitive adhesive according to any one of [1] to [4], containing 1 to 40% by weight of the non-functional acrylic polymer.
[6] The pressure-sensitive adhesive according to any one of [1] to [5], wherein the crosslinkable group of the crosslinkable acrylic polymer is a carboxyl group.
[7] The pressure-sensitive adhesive according to any one of [1] to [6], wherein the crosslinking agent is an epoxy-based crosslinking agent.
[8] A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer produced from the pressure-sensitive adhesive according to any one of [1] to [7].
[9] The pressure-sensitive adhesive sheet according to [8], wherein a release sheet is formed on at least one surface of the pressure-sensitive adhesive layer.
[10] The pressure-sensitive adhesive sheet according to [8], wherein release sheets are formed on both sides of the pressure-sensitive adhesive layer.
[11] The pressure-sensitive adhesive sheet according to any one of [8] to [10], wherein the pressure-sensitive adhesive layer has a laminated structure.
[12] The pressure-sensitive adhesive sheet according to any one of [8] to [11], wherein the pressure-sensitive adhesive sheet is used for bonding a member having irregularities with a height difference of 5 μm or more on the surface.
[13] The pressure-sensitive adhesive sheet according to [12], wherein the member is an optical member.
[14] An optical laminate bonded by the pressure-sensitive adhesive sheet according to [13].

  The pressure-sensitive adhesive of the present invention is excellent in unevenness followability, high in adhesive strength and adhesive retention, and excellent in high temperature and high humidity durability. For this reason, even if it is the uneven | corrugated surface which performed printing and etching, according to the adhesive of this invention, it can bond together effectively, and transparency and color can be maintained over a long period of time.

It is sectional drawing which shows one Embodiment of the adhesive sheet which has a peeling film on both surfaces. It is sectional drawing which shows one embodiment of the adhesion target object with an adhesive layer. It is sectional drawing which shows one embodiment which stuck two adhesion objects with the adhesive layer. It is sectional drawing which shows one embodiment of the adhesion target object with an adhesive layer which has a peeling film. It is sectional drawing which shows one embodiment of the adhesion target object which has an adhesive layer which has a peeling film on both surfaces.

  Below, the adhesive of this invention is demonstrated in detail. The description of the constituent elements described below may be made based on typical embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples. In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.

[Features of pressure-sensitive adhesive of the present invention]
The pressure-sensitive adhesive of the present invention contains a cross-linkable acrylic polymer as a main component and a non-functional acrylic polymer having a weight average molecular weight of 1000 to 5000 and Tg of 0 ° C. or less.

[Non-functional acrylic polymer]
The pressure-sensitive adhesive of the present invention contains a non-functional acrylic polymer. The term “non-functional acrylic polymer” as used herein means a polymer consisting only of an acrylic monomer unit having no functional group other than an acrylate group, an acrylic monomer unit having no functional group other than an acrylate group, and It means a polymer composed of non-acrylic monomer units having no functional group. “Monomer unit” means a repeating unit constituting a polymer. An “acrylic monomer” is a compound having a (meth) acryloyl group. “(Meth) acryloyl group” means an acryloyl group or a methacryloyl group.

As an acrylic monomer unit which does not have a functional group, the (meth) acrylic acid ester unit which substituted the hydrogen atom of the carboxyl group of (meth) acrylic acid with the hydrocarbon group is mentioned, for example. 1-18 are preferable and, as for carbon number of this hydrocarbon group, 1-8 are more preferable.
Specific examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n- (meth) acrylate Octyl, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, N-dodecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, ( Data), and benzyl acrylate. These may be used individually by 1 type and may use 2 or more types together.
In the present invention, “(meth) acrylic acid” means containing both “acrylic acid” and “methacrylic acid”.

Examples of the non-acrylic monomer having no functional group include a non-functional monomer having a polymerizable ethylene group. 0-18 are preferable and, as for carbon number of atomic groups other than the polymerizable ethylene group of this monomer, 0-8 are more preferable.
Specific examples of the non-acrylic monomer having no functional group include ethylene, propylene, and styrene.

  The content of the acrylic monomer unit having no functional group other than the acrylate group in the non-functional acrylic polymer is preferably 70 to 100% by weight, more preferably 80 to 100% by weight, and 90 More preferably, it is -100 weight%.

  The non-functional acrylic polymer contained in the pressure-sensitive adhesive of the present invention is a non-functional acrylic polymer having a weight average molecular weight of 1000 to 5000. The weight average molecular weight is preferably 1000 or more, and more preferably 2000 or more. Moreover, it is preferable that it is 5000 or less, and it is more preferable that it is 4000 or less. When the weight average molecular weight is less than 1000, a pressure-sensitive adhesive having sufficient unevenness followability and high temperature and high humidity durability cannot be obtained. When the weight average molecular weight is more than 5000, a pressure-sensitive adhesive having sufficient unevenness followability and adhesive force cannot be obtained.

  The non-functional acrylic polymer contained in the pressure-sensitive adhesive of the present invention is a non-functional acrylic polymer having a glass transition temperature (Tg) of 0 ° C. or lower. Tg is preferably 0 ° C. or lower, more preferably −30 ° C. or lower, and further preferably −50 ° C. or lower. When Tg is higher than 0 ° C., a pressure-sensitive adhesive having sufficient unevenness followability cannot be obtained.

  The non-functional acrylic polymer contained in the pressure-sensitive adhesive of the present invention preferably has a viscosity at 25 ° C. of 4800 mPa · s or less. The viscosity at 25 ° C. here is a value measured using a B-type viscometer. The viscosity at 25 ° C. of the non-functional acrylic polymer is more preferably 4800 mPa · s or less, and further preferably 3000 mPa · s or less. Moreover, it is preferable that the viscosity at 25 degrees C of a nonfunctional acrylic polymer is 500 mPa * s or more.

  The pressure-sensitive adhesive (excluding the solvent) of the present invention preferably contains 1.0% by weight or more of a non-functional acrylic polymer, more preferably 5.0% by weight or more, and 40% by weight or less. It is preferably contained, and more preferably 30% by weight or less. When the content of the non-functional group acrylic polymer is equal to or higher than the lower limit, a pressure-sensitive adhesive having sufficient unevenness followability is easily obtained. Moreover, if a non-functional acrylic polymer is below the said upper limit, it will become easy to obtain the adhesive which has high temperature high-humidity durability.

[Crosslinkable acrylic polymer]
The pressure-sensitive adhesive of the present invention contains a crosslinkable acrylic polymer as a main component. The “main component” here means 40% by weight or more of the pressure-sensitive adhesive (excluding the solvent). The pressure-sensitive adhesive of the present invention preferably contains 50% by weight or more of a crosslinkable acrylic polymer, and more preferably 70% by weight or more.
The crosslinkable acrylic polymer is a polymer having a non-crosslinkable acrylic monomer unit and a crosslinkable monomer unit. Here, the non-crosslinkable acrylic monomer is an acrylic monomer having no crosslinkable group, and the crosslinkable monomer is a monomer having a crosslinkable group. The crosslinkable monomer may be an acrylic monomer or a non-acrylic monomer as long as it is polymerizable with the non-crosslinkable acrylic monomer, and is preferably an acrylic monomer. . Examples of the crosslinkable group include a carboxyl group, a hydroxy group, an amino group, an epoxy group, and a glycidyl group, and a carboxyl group and a hydroxy group are preferable.

Examples of the non-crosslinkable acrylic monomer unit include a (meth) acrylic acid ester unit in which a hydrogen atom of a carboxyl group of (meth) acrylic acid is substituted with a hydrocarbon group. 1-18 are preferable and, as for carbon number of this hydrocarbon group, 1-8 are more preferable. In the hydrocarbon group, the hydrocarbon group may have a substituent. The substituent is not particularly limited as long as it does not contain a crosslinkable group, and examples thereof include alkoxy groups such as methoxy group and ethoxy group.
Specific examples of the (meth) acrylic acid ester include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, Isobutyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n- (meth) acrylate Octyl, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-undecyl (meth) acrylate, N-dodecyl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ( Data) ethoxyethyl acrylate, cyclohexyl (meth) acrylate include benzyl (meth) acrylate. These may be used individually by 1 type and may use 2 or more types together.
Among these, n-butyl acrylate, 2-ethylhexyl acrylate, and methyl acrylate are preferable from the viewpoint of adhesiveness.

The crosslinkable monomer unit includes a carboxyl group-containing copolymerizable monomer unit, a hydroxy group-containing copolymerizable monomer unit, an amino group-containing copolymerizable monomer unit, and a glycidyl group-containing copolymerizable monomer. Examples include body units. Examples of the carboxyl group-containing copolymerizable monomer include α, β-unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, grataconic acid, and anhydrides thereof. Such as things.
Examples of the hydroxy group-containing copolymerizable monomer include (meth) acrylic acid such as 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate. Hydroxyalkyl, (meth) acrylic acid such as mono (diethylene glycol) (meth) acrylic acid [(mono, di or poly) alkylene glycol], (meth) acrylic acid lactone such as monocaprolactone (meth) acrylic acid, N-methylol (Meth) acrylamide is mentioned.
Examples of the amino group-containing copolymerizable monomer include (meth) acrylamide, allylamide, N, N-dimethyl (meth) acrylamide, N-tertbutyl (meth) acrylamide, dimethylaminoethyl (meth) acrylate, ( Examples include diethylaminoethyl methacrylate) and tertbutylaminoethyl (meth) acrylate.
Examples of the glycidyl group-containing copolymerizable monomer include glycidyl (meth) acrylate.

Among these, from the point of low adhesiveness, crosslinkability and polymerizability, and the corrosiveness of metals such as tin-doped indium oxide used for transparent conductive films and copper used for electromagnetic shielding, a hydroxy group-containing copolymerizable monomer Body, hydroxyalkyl (meth) acrylate is more preferable, 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate are particularly preferable.
In addition, when a carboxyl group-containing copolymerizable monomer unit is contained as a crosslinkable monomer unit, the acidity becomes strong, so when a corrosive film such as a tin-doped indium oxide film or a metal film is in contact with these, May corrode the film. Therefore, when applying the pressure-sensitive adhesive of the present invention to such an object having corrosivity, from the viewpoint of corrosion prevention, a carboxyl group-containing copolymerizable monomer unit as a crosslinkable monomer unit The content of is preferably less than 0.5% by weight, and more preferably not contained at all.

  The content of the crosslinkable monomer unit in the crosslinkable acrylic polymer is preferably 0.01 to 20% by weight, and more preferably 0.5 to 10% by weight. If the content of the crosslinkable monomer unit is not less than the above lower limit value, it can be sufficiently cross-linked, and the swelling prevention and punching performance can be further improved. There is a tendency to ensure performance and curl prevention performance.

Moreover, the crosslinkable acrylic polymer may have other monomer units other than the non-crosslinkable acrylic monomer unit and the crosslinkable monomer unit. Examples of other monomers include (meth) acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinyl pyrrolidone, vinyl pyridine, and acrylamide.
The content of other monomer units in the crosslinkable acrylic polymer is preferably 0.1 to 20% by weight, and more preferably 0.5 to 10% by weight. If the content of other monomer units is not less than the lower limit, the physical properties can be easily adjusted, and if it is not more than the upper limit, yellowing due to deterioration with time can be prevented.

When the monomer is polymerized to synthesize a crosslinkable acrylic polymer, it is preferable to use a polymerization initiator. A preferable polymerization initiator that can be used includes a polymerization initiator having no repeating unit. Examples thereof include azo polymerization initiators such as azobisisobutyronitrile and azobisvaleronitrile, and peroxide polymerization initiators such as benzoyl peroxide and lauryl peroxide. These polymerization initiators can be used more preferably than, for example, a polymer azo polymerization initiator having a polymer segment and an azo group. The molecular weight of the polymerization initiator used in the present invention is preferably 1000 or less, more preferably 700 or less, and even more preferably 500 or less. About a lower limit, it can be set as 100 or more, for example.
The weight average molecular weight of the crosslinkable acrylic polymer is preferably 100,000 or more, more preferably 200,000 or more, further preferably 300,000 or more, and further preferably 350,000 or more, Further, it is preferably 2 million or less, more preferably 1.5 million or less, further preferably 1 million or less, and even more preferably 750,000 or less.

[Crosslinking agent]
The pressure-sensitive adhesive of the present invention contains a crosslinking agent.
Examples of the crosslinking agent include isocyanate compounds, epoxy compounds, oxazoline compounds, aziridine compounds, metal chelate compounds, melamine compounds, and the like. Among these crosslinking agents, an isocyanate compound and an epoxy compound are preferable because the acrylic polymer can be easily crosslinked. In particular, when the acrylic polymer contains only a hydroxy group-containing copolymerizable monomer unit as a crosslinkable monomer unit, it is preferable to use an isocyanate compound from the reactivity of the hydroxy group. Moreover, when an acrylic polymer contains only a carboxyl group-containing copolymerizable monomer unit as a crosslinkable monomer unit, an isocyanate compound, an epoxy compound, an aziridine compound, or a melamine compound may be used due to the reactivity of the carboxyl group. It is particularly preferable to use an epoxy compound or an isocyanate compound.

Examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol A / epichlorohydrin type epoxy resin, N, N, N ′, N′— And polyfunctional epoxy compounds such as tetraglycidyl-m-xylenediamine, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, N, N-diglycidylaniline, N, N-diglycidyltoluidine and the like. .
Examples of the isocyanate compound include tolylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate.

  Examples of crosslinking agents other than epoxy compounds and isocyanate compounds include 2,2′-bishydroxymethylbutanol tris [3- (1-aziridinyl) propionate], 4,4′-bis (ethyleneiminocarbonylamino) diphenylmethane, and the like. Functional aziridine compounds; for example, metal chelates such as coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium with acetylacetone and ethyl acetoacetate Is mentioned.

  It is preferable that the content of the crosslinking agent is appropriately selected according to the desired pressure-sensitive adhesive properties. Usually, it is preferably 0.01% by weight or more of the pressure-sensitive adhesive of the present invention (excluding the solvent), more preferably 0.02% by weight or more, and further preferably 0.04% by weight or more. It is preferably 0.20% by weight or less, more preferably 0.18% by weight or less, and further preferably 0.14% by weight or less.

[Other components of adhesive]
Components other than the above may be contained in the pressure-sensitive adhesive of the present invention. A polyester resin, amino resin, epoxy resin, or polyurethane resin may be used in combination as a resin other than the main component acrylic polymer or non-functional acrylic polymer. However, the amount of such resin added is preferably 40% by weight or less of the pressure-sensitive adhesive (excluding the solvent), more preferably 35% by weight or less, and further preferably 30% by weight or less. .

Further, the pressure-sensitive adhesive of the present invention includes an antioxidant, a metal corrosion inhibitor, a tackifier, a silane coupling agent, an ultraviolet absorber, a light stabilizer such as a hindered amine compound, a filler, an ionic property as necessary. Additives such as liquids may be included. Examples of the antioxidant include phenolic antioxidants, amine-based antioxidants, lactone-based antioxidants, phosphorus-based antioxidants, sulfur-based antioxidants, and the like. These antioxidants may be used alone or in combination of two or more. As the metal corrosion inhibitor, a benzotriazole-based resin is preferable because of the compatibility and high effect of the pressure-sensitive adhesive. Examples of the tackifier include rosin resin, terpene resin, terpene phenol resin, coumarone indene resin, styrene resin, xylene resin, phenol resin, and petroleum resin. Examples of the silane coupling agent include mercaptoalkoxysilane compounds (for example, mercapto group-substituted alkoxy oligomers). Examples of the ultraviolet absorber include benzotriazole compounds and benzophenone compounds. Examples of the ionic liquid include ionic liquids such as a nitrogen-containing onium salt, a sulfur-containing onium salt, or a phosphorus-containing onium salt, and are preferably described in paragraph numbers 0018 to 0028 of JP2011-89138A. Ionic liquids to be used. The description of paragraph numbers 0018 to 0028 in Japanese Patent Application Laid-Open No. 2011-89138 is incorporated herein as part of this specification.
The blending amount when these additives are used is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, still more preferably 0.1% by weight or more of the pressure-sensitive adhesive (excluding the solvent). It is preferably 10% by weight or less, more preferably 5% by weight or less, and further preferably 3% by weight or less.
In addition, the material and aspect described in Paragraph Nos. 0021 to 0105 of JP 2011-148965 A can also be adopted in the present invention, and these descriptions are cited here as a part of this specification.

  Further, as an additive, an ionic liquid such as a nitrogen-containing onium salt, a sulfur-containing onium salt, or a phosphorus-containing onium salt, preferably from the group consisting of the following formulas (A), (B), (C) and (D) By using the selected ionic salt, the pressure-sensitive adhesive can have antistatic properties. The ionic salt is liquid or solid at 25 ° C.

［式（Ａ）中のＲ^１は炭素数４〜２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ^２およびＲ^３は、同一又は異なって、水素または炭素数１〜１６の炭化水素基を表し、ヘテロ原子を含んでも良い。但し、窒素原子が２重結合を含む場合、Ｒ^３はない。式（Ｂ）中のＲ^４は、炭素数２〜２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ^５、Ｒ^６、およびＲ^７は、同一又は異なって、水素または炭素数１〜１６の炭化水素基を表し、ヘテロ原子を含んでも良い。
式（Ｃ）中のＲ^８は、炭素数２〜２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ^９、Ｒ^１０、およびＲ^１１は、同一又は異なって、水素または炭素数１〜１６の炭化水素基を表し、ヘテロ原子を含んでも良い。式（Ｄ）中のＸは、窒素、硫黄、又はリン原子を表し、Ｒ^１２、Ｒ^１３、Ｒ^１４、およびＲ^１５は、同一又は異なって、炭素数１〜２０の炭化水素基を表し、ヘテロ原子を含んでも良い。但しＸが硫黄原子の場合、Ｒ^１２はない。］

[R ¹ in Formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may contain a hetero atom, and R ² and R ³ may be the same or different, and may be hydrogen or carbon atoms having 1 to 16 carbon atoms. Represents a hydrogen group and may contain a heteroatom. However, when the nitrogen atom contains a double bond, there is no R ³ . R ⁴ in the formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms, and may contain a hetero atom, and R ⁵ , R ⁶ , and R ⁷ are the same or different and each represents hydrogen or carbon number 1 Represents ˜16 hydrocarbon groups and may contain heteroatoms.
R ⁸ in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms, and may contain a hetero atom, and R ⁹ , R ¹⁰ , and R ¹¹ are the same or different and each represents hydrogen or carbon number 1 Represents ˜16 hydrocarbon groups and may contain heteroatoms. X in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, R ¹² , R ¹³ , R ¹⁴ , and R ¹⁵ are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms, Hetero atoms may be included. However, if X is a sulfur ^{atom, R 12} is not. ]

  Examples of the cation represented by the formula (A) include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, and a cation having a pyrrole skeleton. Specific examples include 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl-3. -Methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidinium cation 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, and 1-ethylcarbazole cation.

Examples of the cation represented by the formula (B) include an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.
Specific examples include 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl- 3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethyl Imidazolium cation, 1,3-dimethyl-1,4 5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6 -Tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1, 3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation And the like.

  Examples of the cation represented by the formula (C) include a pyrazolium cation and a pyrazolinium cation. Specific examples include 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation and the like.

  Examples of the cation represented by the formula (D) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and those in which a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. Specifically, for example, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, N, N-diethyl -N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N, N-dip Pyrammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl-N, N-dihexylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethyl Methylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethyl Ammonium On and the like.

On the other hand, the anion component is not particularly limited as long as it satisfies that it becomes an ionic liquid. For example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , F (HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ ) (CF ₃ CO) N ^{− and the} like are used. In particular, an anion component containing a fluorine atom is preferably used because an ionic compound having a low melting point is obtained.

  Although the said ionic salt may use a commercially available thing, it can also synthesize | combine suitably. The method for synthesizing the ionic salt in a liquid form is not particularly limited as long as the target ionic liquid can be obtained. For example, the document “ionic liquids—the forefront and future of development” — [ Use the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method described in [Published by CMC Publishing Co., Ltd.], a method according to this, or a method combining these with conventional methods. be able to.

[Application of adhesive]
The pressure-sensitive adhesive of the present invention can be directly applied to a material to be adhered. The applicable law is not particularly limited. For example, it may be dissolved in a solvent and applied as a solution and then dried (solution method), or may be formed into a sheet and stacked (sheet method). When applied as a solution, it may be applied to a release film and then brought into contact with an adhesive object (transfer method), and bonded to a release film having a different release performance, and finished into a sheet having a release film on both sides. Then, you may make an adhesion target object contact the adhesion layer which peeled the peeling film (adhesive sheet method).
When the adhesive is applied in the form of a solution, examples of the solvent include methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, benzene, dioxane, acetonitrile, tetrahydrofuran, diglyme, dimethyl sulfoxide, N-methylpyrrolidone, dimethylformamide and the like. Can be used. After applying the solution, the pressure-sensitive adhesive layer can be formed by removing the solvent at high temperature or under reduced pressure.

[Thickness of adhesive layer]
When forming an adhesive layer using the adhesive of this invention, the thickness in particular of an adhesive layer is not restrict | limited.
Usually, it is preferably 50 μm or more, more preferably 100 μm or more, and preferably 500 μm or less. If the thickness of the pressure-sensitive adhesive layer is equal to or more than the lower limit value, sufficient followability to unevenness can be obtained, and there is a tendency that problems such as bubbles are unlikely to occur. Also, if the thickness of the pressure-sensitive adhesive layer is not more than the upper limit of the previous period, the light transmittance of the pressure-sensitive adhesive layer tends to decrease, or the problem that the pressure-sensitive adhesive protrudes during the punching process of the pressure-sensitive adhesive is less likely to occur. is there.

[Adhesive layer having a laminated structure]
The pressure-sensitive adhesive layer may have a laminated structure of two or more layers. When it has a laminated structure of two or more layers, at least one layer is required to be an adhesive layer that satisfies the conditions of the present invention. For example, a two-layer laminated structure composed of a layer satisfying the conditions of the present invention / a layer not satisfying the conditions of the present invention, a layer satisfying the conditions of the present invention / a two-layer laminated structure composed of another layer satisfying the conditions of the present invention, Specific examples include a three-layered structure composed of a layer that satisfies the conditions of the present invention / a layer that does not satisfy the conditions of the present invention / a layer that satisfies the conditions of the present invention. At this time, it is desirable that the pressure-sensitive adhesive layer satisfying the conditions of the present invention has a thickness in the above-mentioned preferable range. When the pressure-sensitive adhesive layer has a laminated structure of a layer satisfying the conditions of the present invention and a layer not satisfying the conditions of the present invention, the thickness of the layer satisfying the conditions of the present invention is 50% or more of the total thickness of the pressure-sensitive adhesive layer. Preferably, it is 70% or more, more preferably 85% or more.

  The pressure-sensitive adhesive layer that satisfies the conditions of the present invention is preferably configured so as to directly contact a pressure-sensitive adhesive object having irregularities. When the pressure-sensitive adhesive layer has a laminated structure of a layer that satisfies the conditions of the present invention and a layer that does not satisfy the conditions of the present invention, the weight average of the crosslinkable acrylic polymer that is the main component contained in the layer that satisfies the conditions of the present invention It is preferable to increase the weight average molecular weight of the crosslinkable acrylic polymer as the main component contained in the layer that does not satisfy the conditions of the present invention, rather than the molecular weight. For example, the latter weight average molecular weight can be increased by 200,000 or more, or can be increased by 400,000 or more.

[Adhesive sheet]
The pressure-sensitive adhesive of the present invention can be formed into a sheet to form a pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet can be produced, for example, by dissolving a pressure-sensitive adhesive in a solvent and removing the solvent after coating. The coating method can be appropriately selected from knife coaters, micro bar coaters, air knife coaters, reverse roll coaters, reverse gravure coaters, bario gravure coaters, die coaters, curtain coaters and the like.
The pressure-sensitive adhesive sheet of the present invention is prepared, for example, by preparing a release film provided with a release agent layer on a substrate such as a polymer film, and applying and drying the pressure-sensitive adhesive coating liquid of the present invention on the release agent layer. Can be obtained. As shown in FIG. 1, the release sheet preferably has a structure in which the upper and lower sides of the pressure-sensitive adhesive layer 112 are sandwiched between two release films 114 each having a release agent layer 115 provided on a base material 116. The pressure-sensitive adhesive sheet of the present invention having such a structure is obtained by applying and drying the pressure-sensitive adhesive coating liquid on the release layer surface of the first release film in which the release agent layer is provided on the polymer film, and then the first release film and Can be obtained by bonding and pressure-bonding the release layer surface of the second release film composed of release agent layers having different release forces to the pressure-sensitive adhesive layer surface.
When the release force of the first release film and the second release film is close, when the release film on the light release force side is peeled off, there is a tearing phenomenon in which the adhesive floats from the release film on the heavy release force side. Occur. Therefore, the peel force of the release film on the heavy peel force side is preferably 0.5 N / 50 mm to 1.5 N / 50 mm, and the peel force of the peel film on the light peel force side is 0.01 N / 50 mm to 0.4 N. / 50 mm is preferable. Further, the value of heavy peeling force / light peeling force is preferably 1.5 or more, and more preferably 2.0 or more.
Moreover, at this time, when the difference of the peeling force of two peeling films can be maintained, after apply | coating an adhesive coating liquid previously to a 2nd peeling film, a 1st peeling film may be bonded and pressure-bonded. .
The shape of the pressure-sensitive adhesive sheet may be a sheet shape or may be wound up in a roll shape.

  If a pressure-sensitive adhesive sheet is used, there is no need for the application of a pressure-sensitive adhesive at the bonding stage and a drying step, and it is easy to apply pressure by laminating a pressure-sensitive adhesive sheet between two pressure-sensitive adhesive objects and pressing it. . That is, two adhesion objects can be easily adhered by laminating the first adhesion object, the adhesive sheet, and the second adhesion object in this order, and pressurizing the obtained laminate. .

[Adhesive object with adhesive layer]
As shown in FIG. 2, the pressure-sensitive adhesive object 110 with the pressure-sensitive adhesive layer can be manufactured by laminating the pressure-sensitive adhesive of the present invention on the surface of the pressure-sensitive adhesive object 111 as the pressure-sensitive adhesive layer 112. As a method of applying the pressure-sensitive adhesive to the surface of the pressure-sensitive adhesive object, the above-described solution method, sheet method, or the like can be used. As shown in FIG. 3, the pressure-sensitive adhesive object with the pressure-sensitive adhesive layer is easily bonded to the pressure-sensitive adhesive object 113 to which the pressure-sensitive adhesive object 111 is to be attached by pressing the pressure-sensitive adhesive layer 112 so that the pressure-sensitive adhesive layer 112 is in contact with the pressure-sensitive adhesive object. Can be attached to objects.
Moreover, after peeling off the peeling film 114 on one side of the pressure-sensitive adhesive sheet using the pressure-sensitive adhesive of the present invention shown in FIG. 1, the pressure-sensitive adhesive 111 is pressure-bonded to the pressure-sensitive adhesive layer 112 as shown in FIG. A layered adhesive object can be produced. At this time, in order to prevent the adhesive from sticking to an unintended object or being deteriorated by being exposed to air, the release film should be peeled off just before trying to bond as much as possible. .
Furthermore, when forming the above-mentioned pressure-sensitive adhesive of the present invention into a sheet to form a pressure-sensitive adhesive sheet, after being applied to the release film, a pressure-sensitive adhesive object with a pressure-sensitive adhesive layer can be produced by directly pressing the pressure-sensitive adhesive object, The manufacturing method can be properly used for convenience.
By performing known surface treatment such as corona treatment or plasma treatment on the bonding surface of the adhesion target object to be bonded, the adhesiveness between the pressure-sensitive adhesive layer and the adhesion target object can be further improved.
Such a pressure-sensitive adhesive-attached object may have a sheet shape or a roll shape.

As shown in FIG. 3, the pressure-sensitive adhesive layer-attached adhesive object can be easily obtained by stacking and pressing the second pressure-sensitive adhesive object 113 to be bonded to the pressure-sensitive adhesive layer 112 from which the release film has been peeled. It can stick to the 2nd adhesion target object 113. At this time, in order to prevent the adhesive from sticking to an unintended object or being deteriorated by being exposed to air, the release film should be peeled off just before trying to bond as much as possible. .
Moreover, as a means for suppressing such a case, a mode in which a release film 114 is further formed on the pressure-sensitive adhesive layer 112 as shown in FIG. 4 can be cited as a preferred example. The release film 114 preferably includes a base material 116 and a release agent layer 115. At this time, lamination is performed such that the release film 115 side of the release film contacts the surface of the pressure-sensitive adhesive layer 112. When making especially roll shape, it is preferable to apply and roll up such a release film, peel off the release film at the time of use, and stick the adhesive object with the adhesive layer to the second adhesive object. .
In addition, you may form the adhesive layer on both surfaces of the adhesion target object. Moreover, you may form said peeling film further on the adhesive layer formed in both surfaces. As a specific example of such an embodiment, the embodiment shown in FIG. 5 can be cited. At the time of use, for example, the adhesive layer exposed by peeling off one release film is superimposed on the adhesive object, and the other adhesive layer exposed by peeling the other release film is used as another adhesive object. It is possible to adhere by pressurizing the whole.

As the release film substrate, for example, various polymer films can be used, and polyethylene terephthalate is particularly preferable from the viewpoint of surface smoothness and processability. As the release agent constituting the release agent layer, for example, a general-purpose addition type or condensation type silicone release agent or a long-chain alkyl group-containing compound is used. In particular, an addition type silicone release agent having high reactivity is preferably used. Specific examples of silicone release agents include BY24-4527 and SD-7220 manufactured by Toray Dow Corning Silicone, KS-3600, KS-774, and X62-2600 manufactured by Shin-Etsu Chemical Co., Ltd. Is mentioned. Further, the silicone-based release agent may contain a silicone resin that is an organosilicon compound having a SiO ₂ unit and (CH ₃ ) ₃ SiO _1/2 unit or CH ₂ ═CH (CH ₃ ) SiO _1/2 unit. preferable. Specific examples of the silicone resin include BY24-843, SD-7292, SHR-1404, etc. manufactured by Toray Dow Corning Silicone, KS-3800, X92-183, manufactured by Shin-Etsu Chemical Co., Ltd., and the like.

[Adhesive object]
The adhesion target object which adheres using the adhesive of this invention is not restrict | limited in particular. For example, glass, a film, etc. can be mentioned. By using the pressure-sensitive adhesive of the present invention, it is possible to realize adhesion with low haze and high transparency. Therefore, the surface protection plate of the display device and the adhesion of the touch panel module, the surface protection plate and the image display module, or the touch panel module It can be preferably used for adhesion of an image display module.
Examples of the surface protective plate include a glass plate and a resin plate subjected to frame printing, and the material is not particularly limited as long as transparency is ensured. Specifically, in addition to inorganic materials such as soda glass, alkali-free glass, and tempered glass, transparent resins such as polyethylene terephthalate resin, polycarbonate resin, and polymethyl methacrylate resin are desirable.
Examples of adhesive objects of touch panel modules include sensor glass and sensor films that have been subjected to conductive treatment, protective films on the top of the conductive layer, or glass that is opposite to sensor glass and sensor films that have been subjected to conductive treatment, Examples thereof include a film and a hard coat layer on the surface thereof. Examples of the film subjected to the conductive treatment include polyethylene terephthalate, polycarbonate, and cycloolefin resin.
Examples of the adhesive object of the image display module include an optical film and a display panel, and it is preferable to provide an optical laminate by bonding them using the adhesive of the present invention. As an optical film, for example, it has optical anisotropy and is formed to protect a retardation film (optical compensation film) having a retardation in a specific in-plane direction and a retardation in a specific thickness direction, and a polarizer. Polarizer protective film (sometimes called a polarizing plate protective film), a polarizing plate base material that functions as a support for the polarizer in the polarizing plate, an antireflection film that suppresses reflection of light incident from the outside, and the like be able to. Examples of materials constituting such an optical film include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate, and cellulose propionate butyrate. Examples include cellulose acylate; cycloolefin resin. As a commercially available resin material that can be used as a retardation film, Arton (manufactured by JSR), Zeonore (manufactured by Nippon Zeon), and the like can be given. On the other hand, glass etc. can be mentioned as a display panel.
Examples of typical display devices include a liquid crystal display device (liquid crystal display panel), a plasma display device (plasma display panel), and an organic electroluminescence display device (organic EL panel).

Since the surface protective plate, the touch panel module, and the image display module can be effectively adhered using the adhesive of the present invention, in addition to the stationary image display device, a mobile phone, a smartphone, or a tablet terminal as a mobile terminal A mobile personal computer can be preferably manufactured.
Since the adhesive of this invention is excellent in uneven | corrugated followable | trackability, it is preferable to use for the bonding of the member which has an unevenness | corrugation on the surface especially. That is, bonding between a member having irregularities on the surface and a member having no irregularities on the surface, bonding between members of the same type having irregularities on the surface, a member having irregularities on the surface and a member having irregularities on the other surface The pressure-sensitive adhesive of the present invention can be preferably used for pasting and the like. The term “member having irregularities on the surface” as used herein means a member having irregularities with a height difference (step) of 5 μm or more on the surface of the member to be bonded. As a specific example, a surface protective plate subjected to frame printing can be cited as a desirable example. The printing step of the surface protection plate tends to be thicker from 15 μm to 60 μm than the need for decoration and concealment from about 10 μm until recently, and the pressure-sensitive adhesive of the present invention is excellent in the unevenness followability, and the bonding In addition to preventing air bubbles from being left behind, the display device after bonding can be used for a long time or when used outdoors. Even when the is placed under high humidity, it is possible to prevent the generation of bubbles and maintain a stable display function. That is, even when left under a high temperature and high humidity for a long time, the pressure-sensitive adhesive of the present invention causes the display color to change, whitening progresses, and distortion and display unevenness occur due to the generation of bubbles. Can be prevented.

The features of the present invention will be described more specifically with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below. In the examples, “parts” and “%” represent “parts by weight” and “% by weight” unless otherwise specified. In addition, the weight average molecular weight _Mw is measured by using a gel permeation chromatography (pump: PU-980, detector: RI-2031Plus, manufactured by JASCO Corporation) for a sample in which THF (tetrahydrofuran) is dissolved, and polystyrene. It is the value obtained by the standard. Further, the glass transition temperature (Tg) was measured by using DSC (simultaneous differential thermogravimetric measuring device) manufactured by SII. The viscosity at 25 ° C. was measured using a B-type viscometer manufactured by TOKIMEC.

(1) Preparation of pressure-sensitive adhesive solution 100 parts by weight of an acrylic polymer having a carboxyl group (manufactured by Soken Chemical Co., Ltd .: SK-2094), and 0 of an epoxy-based crosslinking agent (manufactured by Soken Chemical Co., Ltd .: E-5XM) 0.1 part by weight, 0.15 part by weight of silane coupling agent (manufactured by Soken Chemical Co., Ltd .: C-50), 0.01 part by weight of metal corrosion inhibitor (manufactured by Soken Chemical Co., Ltd .: M), table The adhesives of Examples 1 to 4 and Comparative Examples 1 to 5 were diluted by 5.0 parts by weight of the low molecular weight acrylic polymer described in 1 and ethyl acetate as a solvent in a concentration of 30% by weight. An agent solution was prepared. In Comparative Example 1, no low molecular weight acrylic polymer was added. The low molecular weight acrylic polymers added in Examples 1 to 4 and Comparative Examples 2 to 5 are all liquid at 25 ° C., the non-volatile content is 98% or more, and the specific gravity is 1.02 to 1.12. It is in a range, a refractive index is 1.46-1.47, and is a 100% polymer of a crosslinkable acrylic monomer.

(2) Production of pressure-sensitive adhesive sheets Using the pressure-sensitive adhesive solutions of Examples 1 to 4 and Comparative Examples 1 to 5 prepared in (1), according to the following procedure, Examples 1A to 4A and Comparative Examples 1A to 5A Each pressure-sensitive adhesive sheet was produced.
As a first release sheet, a release film [Mitsubishi Resin Co., Ltd., MRV # 50] provided with a release layer on a PET film is prepared, and on the release agent layer of the first release sheet, (1 The adhesive solution prepared in (1) was applied with a knife coater. As a second release sheet, a release film [A50 # 50, manufactured by Teijin DuPont Films Co., Ltd.] provided with a release agent layer on a PET film is prepared, and the release layer side is on the coated surface of the adhesive solution. After heating at 40 ° C. for 2 minutes, it was further heated at 110 ° C. for 2 minutes. This produced the adhesive sheet which has an adhesive layer of the thickness shown in Table 2 between the 1st release sheet and the 2nd release sheet.

(3) The pressure-sensitive adhesive sheet produced in the pressure- sensitive adhesive strength test (2) is cut into a size of 25 mm × 100 mm, the second pressure-sensitive adhesive layer is peeled off, and the pressure-sensitive adhesive layer exposed is attached to a clean glass plate surface. Two reciprocating pressures were applied with a roller. Adhesion when the pressure-sensitive adhesive layer is peeled off from the glass plate at a tensile rate of 300 mm / min by the 180 degree peeling method (peel method) specified in JIS-Z-0237 after 24 hours from the time of pressure bonding. The force was measured with a Tensilon tensile tester [manufactured by Shimadzu Corporation: Autograph]. Moreover, the adhesive residue on the glass surface after peeling was evaluated in the following four stages. The results are shown in Table 2.
A: No glue residue B: No glue residue (only the edge or part of the glue is left in addition to the edge)
C: There is adhesive residue throughout
D: There is adhesive residue at the time of measurement. As is clear from Table 2, Examples 1A to 4A were not inferior to Comparative Example 1A in which the non-functional acrylic polymer was not added. This indicates that the addition of a non-functional acrylic polymer according to the present invention does not affect the adhesive physical properties. On the other hand, Comparative Example 2A and Comparative Example 3A were inferior to Examples 1A to 4A in adhesive strength after 24 hours had passed since the pressure bonding.

(4) The pressure-sensitive adhesive sheet produced in the holding power test (2) was cut into a size of 25 mm × 100 mm, and the pressure-sensitive adhesive layer exposed by peeling the second release sheet was pasted on a clean SUS board surface, and JIS-Z The holding power test specified in 0237: 2000 was performed and evaluated according to the following criteria. The results are shown in Table 2.
A: No deviation C: There is a deviation As shown in Table 2, no deviation was observed in any of the samples.

(5) Using each pressure-sensitive adhesive sheet of Examples 1 to 4 and Comparative Examples 1 to 4 manufactured in the high-temperature and high-humidity durability test (2), the pressure-sensitive adhesive layer exposed by peeling the second release sheet and 100 μm PET [Toyobo Co., Ltd., Cosmo Shine A4300] is pasted, and then the first release sheet is peeled off and the adhesive layer and glass [Matsunami Glass Industry Co., Ltd .: slide glass S9111] are exposed and pressed. The samples of Examples 1B to 4B and Comparative Examples 1B to 4B were prepared by bonding using a roller. The total light transmittance (Tt) and haze (Hz) of each sample were measured using a turbidimeter [manufactured by Nippon Denshoku Industries Co., Ltd .: Haze Meter NDH2000], and the lightness (L *) and chromaticity (a *, b) *) Was measured using a color difference meter [manufactured by Nippon Denshoku Industries Co., Ltd .: Spectro Color Meter SE2000]. Thereafter, each sample was put in an oven set at 85 ° C. and relative humidity 85%, taken out after 250 hours, and again after 30 minutes haze (Hz), total light transmittance (Tt), lightness (L *), color The degree (a *, b *) was measured. Further, haze (Hz) was also measured after 24 hours from the removal. The results are shown in Table 3 below.
As shown in Table 3, Examples 1B to 4B all had high temperature and high humidity durability. In contrast, Comparative Example 3B had a high untreated Hz value.

(6) Concavity and convexity followability test 1
Using the pressure-sensitive adhesive sheets of Examples 1 to 4 and Comparative Examples 1 to 5 manufactured in (2), the samples of Examples 1C to 4C and Comparative Examples 1C to 5C were manufactured according to the following procedure.
Printing was performed on one side of the glass (thickness: about 0.9 mm) so that unevenness with an elevation difference of 10 μm was formed, whereby uneven glass was obtained. A polyethylene terephthalate (thickness: 188 μm) without unevenness is pasted on the pressure-sensitive adhesive layer that is exposed by peeling off the second release sheet of the pressure-sensitive adhesive sheet produced in (2), and then the first release sheet is peeled off. The uneven surface of the glass with unevenness was bonded to the exposed pressure-sensitive adhesive layer using a pressure roller. A pressure of 0.5 MPa was applied to the obtained transparent laminate for 10 minutes in a pressure degassing apparatus (manufactured by Kurihara Seisakusho: YK-350S) at 40 ° C. Thereafter, the degree of adhesion of the glass with unevenness was evaluated according to the following criteria by observing the generation of bubbles using a microscope (magnification: 25 times). The results are shown in Table 4.
A: Fewer bubbles than Comparative Example B B: Fewer bubbles than Comparative Example C C: Bubbles remain in the uneven or uneven printing step portion as much as or more than Comparative Example 1.
As shown in Table 4, all the samples of the examples showed good unevenness followability. On the other hand, the improvement of uneven | corrugated followable | trackability was not seen by Comparative Examples 2C-5C.

(7) Concavity and convexity followability test 2
In the test of (6), the treatment in the pressure defoaming apparatus was changed to 60 ° C. and 0.6 MPa for 30 minutes, and then the point placed at 80 ° C. for 1 day was changed. (Delay Bubble test). Table 4 shows the results of evaluation based on the criterion (6).
As shown in Table 4, all the samples of the examples showed good results.

(8) Addition amount change test Examples 4D-1 and 4D in which the addition amount of the non-functional acrylic polymer in Example 4 was changed to 4.0 parts by weight, 8.0 parts by weight, and 24.0 parts by weight. -2, Samples of Example 4D-3 were produced. In the samples of Example 4D-1, Example 4D-2, and Example 4D-3, the thickness of the pressure-sensitive adhesive layer was 75 μm. Moreover, the sample of Comparative Example 1D-1 in which the thickness of the pressure-sensitive adhesive layer of Comparative Example 1 was changed to 75 μm was also produced. About each of these samples, the adhesive force test of (3) was done. The results are shown in Table 5.
Moreover, about each sample, the adhesive layer was changed into 175 micrometers and the uneven | corrugated followability test 3 was done according to the following procedures. Printing was performed on one side of the glass (thickness: about 0.9 mm) so that unevenness with an elevation difference of 30 μm was formed, whereby uneven glass was obtained. Next, the second pressure-sensitive adhesive sheet of the sample pressure-sensitive adhesive sheet was peeled off and the exposed pressure-sensitive adhesive layer was attached to glass [Matsunami Glass Industry Co., Ltd .: slide glass S9111] to obtain a glass with a pressure-sensitive adhesive layer. Thereafter, the pressure-sensitive adhesive layer exposed by peeling off the first release sheet of the glass with the pressure-sensitive adhesive layer and the concavo-convex surface of the glass with the concavo-convex were measured using a vacuum bonding machine [Crim Products Co., Ltd .: V-SE160H]. A pressure of 0.6 MPa was applied for 30 seconds in an environment of 100 Pa and a temperature of 30 ° C. A pressure of 0.5 MPa was applied to the obtained transparent laminate for 20 minutes in a pressure degassing apparatus (manufactured by Kurihara Seisakusho: YK-350S) at 50 ° C. Thereafter, the degree of adhesion of the glass with unevenness was evaluated based on the same criteria as in (6) by observing the generation of bubbles using a microscope (magnification: 25 times).
Moreover, as the uneven | corrugated followable | trackability test 4, the transparent laminated body bonded according to the same procedure as (8) was evaluated on the same basis as (7) according to the same procedure as (7). The results are shown in Table 5.
As shown in Table 5, even if the crosslinking agent of the non-functional acrylic polymer is changed, the adhesive strength of Example 4D-1, Example 4D-2, and Example 4D-3 is good, and the unevenness followability is improved. doing. Especially the uneven | corrugated followable | trackability of Example 4D-3 has improved remarkably (evaluation was set to AA).

(9) Cross-linking agent change test The cross-linking agent in Example 4 and Comparative Example 1 was changed to an epoxy-based cross-linking agent [manufactured by Soken Chemical Co., Ltd .: E-5C], and the thickness of the pressure-sensitive adhesive layer was changed to 75 μm. Samples of Example 4D-4 and Comparative Example 1D-1 were produced. About each of these samples, the adhesive force test of (3) was done. Further, the thickness of the pressure-sensitive adhesive layer was changed to 175 μm, and the unevenness followability tests 3 and 4 of (8) were performed. The results are shown in Table 6.
As shown in Table 6, even if the crosslinking agent was changed, the adhesive strength of Example 4D-4 was good, and the unevenness followability was improved.

(10) 2-layered test of the pressure-sensitive adhesive layer [Synthesis of pressure-sensitive adhesive solution of the first adhesive layer]
After nitrogen gas was sealed in a reactor equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen introduction tube, 105 parts by weight of ethyl acetate as a solvent was added. Next, in the reactor, 55 parts by weight of methyl acrylate as a monomer component, 45 parts by weight of 2-ethylhexyl acrylate, 5.0 parts by weight of 4-hydroxyptyl acrylate, azobisiso as an initiator 0.24 parts by weight of butyronitrile (hereinafter referred to as “AIBN”) was added to ethyl acetate so that the monomer concentration was about 50% by weight. Then, after stirring at 50 ° C. for 8 hours in a nitrogen gas stream while stirring, the polymerization reaction was stopped by quenching in an ice-water bath to obtain an acrylate copolymer solution having a weight average molecular weight Mw of 1,000,000. .
0.4 parts by weight of a hexamethylene diisocyanate-based trifunctional adduct (Asahi Kasei Co., Ltd .: P301-75E) as a cross-linking agent with respect to 100 parts by weight of the solid content of this copolymer solution is described in Table 1. The low molecular weight acrylic polymer used in Example 1 was diluted with 5.0 parts by weight of ethyl acetate to give a solution having a concentration of 35% by weight, and each adhesive solution E-1 for Reference Example 1 was diluted. Obtained. In the adhesive solution E-2 for Comparative Example 6, no low molecular weight acrylic polymer was added.

[Synthesis of adhesive solution of second adhesive layer]
An acrylic acid ester copolymer solution having a weight average molecular weight Mw of 1,500,000 was obtained in the same manner as the method for synthesizing the pressure-sensitive adhesive solution of the first pressure-sensitive adhesive layer except that the amount of AIBN used was changed to 0.12 parts by weight. 0.4 parts by weight of hexamethylene diisocyanate trifunctional adduct [Asahi Kasei Co., Ltd .: P301-75E] as a cross-linking agent is added to 100 parts by weight of the solid content of the copolymer solution. It diluted so that it might become a 25 weight% solution, and the solution of adhesive F-1 was obtained.

[Create double-sided adhesive sheet]
As a first release sheet, a release film [Oji Specialty Paper Co., Ltd., 38 μRL-07 (2)] provided with a release layer on a PET film is prepared, and the release agent layer of the first release sheet is The first pressure-sensitive adhesive layer pressure-sensitive adhesive solution (E-1 or E-2) was applied with a knife coater and heated at 100 ° C. for 3 minutes to form a first pressure-sensitive adhesive layer. Reference Example 1 And the 1st adhesive sheet for Comparative Example 6 was obtained. Also, as the second release sheet, a release film [38 μRL-07 (L)] manufactured by Oji Specialty Paper Co., Ltd., which is provided with a release agent layer having a higher release property than the first release sheet on the PET film is prepared. The solution of the pressure-sensitive adhesive solution F-1 for the second pressure-sensitive adhesive layer is applied to the release layer of the second release sheet with a knife coater, heated at 100 ° C. for 3 minutes, and the second pressure-sensitive adhesive. A layer was formed to obtain a second pressure-sensitive adhesive sheet. Next, the first pressure-sensitive adhesive sheet and the second pressure-sensitive adhesive sheet are stacked so that the first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer are in contact with each other, and are pressure-bonded to form the first release sheet and the second release sheet. A pressure-sensitive adhesive sheet having a thickness of the pressure-sensitive adhesive layer shown in Table 7 was produced between the sheets, and pressure-sensitive adhesive sheets of Reference Example 1 and Comparative Example 6 were obtained.

Using the pressure-sensitive adhesive sheets of Reference Example 1 and Comparative Example 6 produced as described above, samples of Reference Example 1D and Comparative Example 6D were produced according to the following procedure.
The unevenness followability test 3 was performed according to the following procedure. Printing was performed on one side of the glass (thickness: about 0.9 mm) so that unevenness with an elevation difference of 30 μm was formed, whereby uneven glass was obtained. Next, the 2nd adhesive layer which peeled and exposed the 2nd peeling sheet of the adhesive sheet of a sample was stuck on glass [Matsunami Glass Industrial Co., Ltd. product: slide glass S9111], and the glass with an adhesive layer was obtained. It was. Then, the 1st adhesive layer which peeled and peeled the 1st peeling sheet of glass with an adhesive layer, and the uneven surface of glass with an unevenness | corrugation were used for the vacuum bonding machine [Crim Products Co., Ltd. product: Sakai-SE160H]. Then, a pressure of 0.6 MPa was applied for 30 seconds in an environment of a degree of vacuum of 100 Pa and a temperature of 30 ° C. A pressure of 0.5 MPa was applied to the obtained transparent laminate for 20 minutes in a pressure degassing apparatus (manufactured by Kurihara Seisakusho: YK-350S) at 50 ° C. Thereafter, the degree of adhesion of the glass with unevenness was evaluated according to the following criteria by observing the generation of bubbles using a microscope (magnification: 25 times).
A: Fewer bubbles than Comparative Example B B: Fewer bubbles than Comparative Example C C: Bubbles remain in the uneven printing step portion as much as or more than Comparative Example 6.
Moreover, as the uneven | corrugated followability test 4, the transparent laminated body bonded according to the same procedure as (8) was evaluated on the same basis as the above. The results are shown in Table 7 . In Table 7, Example 5D should be read as Reference Example 1D.
As shown in Table 7, even if the pressure-sensitive adhesive layer is changed to two layers, the adhesive strength of Reference Example 1D is good, and the unevenness followability is improved.

  The pressure-sensitive adhesive of the present invention is excellent in unevenness followability, high in adhesive strength and adhesive retention, and excellent in high temperature and high humidity durability. For this reason, even if it is the uneven | corrugated surface which performed printing and etching, according to the adhesive of this invention, it can bond together effectively, and transparency and color can be maintained over a long period of time. Therefore, the pressure-sensitive adhesive of the present invention can be effectively used for laminating a wide variety of articles, including display devices that require film and panel adhesion, and has industrial applicability. Is expensive.

110 Adhesive Object with Adhesive Layer 111 Adhesive Object 112 Adhesive Layer 113 Second Adhesive Object 114 Release Film 115 Release Agent Layer 116 Base Material

Claims (15)

Crosslinkable acrylic having a weight average molecular weight of 350,000-750,000 polymerized using a polymerization initiator containing only a hydroxy group-containing copolymerizable monomer unit as a crosslinkable monomer unit and having no repeating unit. with containing a polymer 40% by weight or more, crosslinking agent and pressure-sensitive adhesive which is a solution having a weight average molecular weight containing non-functional acrylic polymer Tg is 0 ℃ or less 1000-5000.   40% by weight or more of a crosslinkable acrylic polymer containing a carboxyl group-containing copolymerizable monomer unit in a range of less than 0.5% by weight, an epoxy-based crosslinking agent, and a weight average molecular weight of 1,000 to 5,000. A pressure-sensitive adhesive comprising a non-functional acrylic polymer having a temperature of 0 ° C. or lower. The pressure-sensitive adhesive according to claim 1 or 2 , wherein the non-functional acrylic polymer has a viscosity at 25 ° C of 4800 mPa · s or less. The pressure-sensitive adhesive according to claim 2 , wherein the crosslinkable acrylic polymer has a weight average molecular weight of 100,000 to 2,000,000. The pressure-sensitive adhesive according to claim 4 , wherein the crosslinkable acrylic polymer is polymerized using a polymerization initiator having no repeating unit, and has a weight average molecular weight of 350,000 to 750,000. The pressure-sensitive adhesive according to any one of claims 1 to 5 , comprising 1 to 40% by weight of the non-functional acrylic polymer.   The pressure-sensitive adhesive according to claim 1, wherein the crosslinking agent is an isocyanate-based crosslinking agent. The pressure-sensitive adhesive according to claim 1 , wherein the crosslinking agent is an epoxy-based crosslinking agent. The adhesive sheet which has an adhesive layer manufactured from the adhesive of any one of Claims 1-8 . The pressure-sensitive adhesive sheet according to claim 9 , wherein a release sheet is formed on at least one surface of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet according to claim 9 , wherein release sheets are formed on both surfaces of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet according to any one of claims 9 to 11 , wherein the pressure-sensitive adhesive layer has a laminated structure. The pressure-sensitive adhesive sheet according to any one of claims 9 to 12 , wherein the pressure-sensitive adhesive sheet is used for bonding a member having unevenness having a height difference of 5 µm or more on the surface. The pressure-sensitive adhesive sheet according to claim 13 , wherein the member is an optical member. The optical laminated body bonded by the adhesive sheet of Claim 14 .

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