TWI612113B - Adhesives, adhesive sheets and optical laminates - Google Patents

Abstract

The present invention is an adhesive, which is characterized by containing a crosslinkable acrylic polymer as a main component, a crosslinker, and a non-functional acrylic polymer having a weight average molecular weight of 1,000 to 5000 and a Tg of 0 ° C or lower. Thing.

Description

Adhesive, adhesive sheet and optical laminate

The present invention relates to an acrylic adhesive and an adhesive sheet having excellent unevenness followability. Moreover, this invention relates to the optical laminated body manufactured using these.

In order to adhere various articles represented by plastic films, panels, etc., an acrylic adhesive mainly containing an acrylic polymer or an adhesive sheet formed by using an acrylic adhesive is widely used. In recent years, the objects to be bonded have become more and more diversified. With the increase in the complexity and complexity of industrial products, the requirements for the properties during or after bonding have become stricter. Therefore, various attempts have been made to improve the performance as an adhesive by further adding additives to the acrylic adhesive.

For example, it is described in Patent Document 1 (Japanese Patent Laid-Open No. 2005-255877) that a carboxyl group-containing crosslinkable monomer unit is added to the acrylic polymer or crosslinker as a main component in an amount of 3 to 10% by weight. , And an adhesive made of an acrylic polymerized oligomer having a cyclic structure having a weight average molecular weight of 3000 to 6000, which has high transparency after lamination, and can prevent bulging or peeling or warping.

Further, it is described in Patent Document 2 (Japanese Patent Application Publication No. 2009-215522) that a carboxyl group-containing crosslinkable monomer unit is added to an acrylic polymer or crosslinker as a main component in an amount of 1 to 10 weight. %, And a weight average molecular weight of 3000 to 6000, an acrylic polymer oligomer having a cyclic structure, which forms a specific adhesive layer with uneven thickness. Landing has excellent transparency, adhesion, and foam resistance after bonding, and the thickness unevenness of the adhesive layer is small.

Furthermore, it is described in Patent Document 3 (Japanese Patent Laid-Open No. 2017-157458) that a carboxyl group-containing crosslinkable monomer unit is added to an acrylic polymer or crosslinker as a main component in an amount of 1 to 10% by weight. Adhesives made of acrylic polymerized oligomers with a weight average molecular weight of 3,000 to 10,000. When applied to uneven parts or thick printed layers, there are no voids on the end faces, but they have an effect on the level difference. Followability, and high durability and adhesion.

Further, it is described in Patent Document 4 (Japanese Patent No. 3327921) that a processing oil, a liquid polyether, a liquid polyterpene, or the like is added to an acrylic polymer or a crosslinking agent as a main component. An adhesive layer formed by an adhesive made of a liquid resin has appropriate elasticity and softness, and can absorb shrinkage stress of a substrate.

Furthermore, it is described in Patent Literature 5 (Japanese Patent Laid-Open No. 2002-047468), Patent Literature 6 (Japanese Patent Laid-Open No. 2002-129123), and Patent Literature 7 (Japanese Patent Laid-Open No. 2003-049141): Copolymers containing Mw / Mn and copolymers containing 0.2 to 10% by weight of carboxyl and / or hydroxyl-containing crosslinkable monomers and 90 to 99.8% by weight of alkyl (meth) acrylate monomers are copolymerized. A non-functional acrylic polymer having a low molecular weight of 1.0 to 2.5 and an adhesive for a cross-linking agent have the following advantages: they exhibit excellent adhesion even under high temperature and humidity conditions, and they do not cause accompanying size Varying foaming or peeling.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2005-255877

[Patent Document 2] Japanese Patent Publication No. 2009-215522

[Patent Document 3] Japanese Patent Laid-Open No. 2011-157458

[Patent Document 4] Japanese Patent No. 3327921

[Patent Document 5] Japanese Patent Laid-Open No. 2002-047468

[Patent Document 6] Japanese Patent Laid-Open No. 2002-129123

[Patent Document 7] Japanese Patent Laid-Open No. 2003-049141

The acrylic adhesives described in these patent documents can exhibit a desired function when they are applied to a surface having a smooth flat surface and bonded together. However, if it is applied to a surface having irregularities, there is a problem that the adhesive cannot sufficiently follow the irregularities, which causes bubbles to remain on the concave portions, which results in a decrease in adhesive force, adhesion holding force, or transparency. In recent years, there has been an increase in the chances of applying adhesives on the surfaces where the concavities and convexities are provided consciously by printing or etching, and it is necessary to provide an adhesive without such problems. In addition, it is also required to be applied to a display panel or the like. Therefore, it is also necessary to provide an adhesive having sufficient durability such as maintaining transparency or hue after bonding even under high temperature and high humidity conditions.

Therefore, the present inventors have tried to develop an adhesive that solves such a technical problem. That is, the present inventors have worked hard to provide an adhesive having excellent unevenness followability, high adhesive force or adhesive retention, and excellent high-temperature, high-humidity durability.

The present inventors and others tried to produce a novel adhesive by adding an oligomer or an additive having various functional groups to an acrylic polymer, and tested it repeatedly. However, it is not easy to find an adhesive that is excellent in unevenness followability, has high adhesive force or adhesive holding force, and is also excellent in high temperature, high humidity durability.

At the end of repeated trial and error, the inventors discovered that as long as a non-functional acrylic polymer that satisfies specific conditions is added, an adhesive can be provided to solve the above problems. The present invention is provided based on such findings, and includes the following constituents.

[1] An adhesive characterized by containing a cross-linkable acrylic polymer as a main component, a cross-linking agent, and a non-functional acrylic polymer having a weight average molecular weight of 1,000 to 5000 and a Tg of 0 ° C or lower. Thing.

[2] The adhesive according to [1], wherein the viscosity at 25 ° C of the non-functional acrylic polymer is 4800 mPa. s or less.

[3] The adhesive according to [1] or [2], wherein the weight average molecular weight of the crosslinkable acrylic polymer is 100,000 to 2 million.

[4] The adhesive according to [3], wherein the crosslinkable acrylic polymer is polymerized using a polymerization initiator without repeating units, and has a weight average molecular weight of 350,000 to 750,000.

[5] The adhesive according to any one of [1] to [4], which contains 1 to 40% by weight of the non-functional acrylic polymer.

[6] The adhesive according to any one of [1] to [5], wherein the crosslinkable group of the crosslinkable acrylic polymer is a carboxyl group.

[7] The adhesive according to any one of [1] to [6], wherein the crosslinking agent is a ring Oxygen-based crosslinking agent.

[8] An adhesive sheet having an adhesive layer made of an adhesive such as any one of [1] to [7].

[9] The adhesive sheet according to [8], wherein a release sheet is formed on at least one side of the adhesive layer.

[10] The adhesive sheet according to [8], wherein release sheets are formed on both sides of the adhesive layer.

[11] The adhesive sheet according to any one of [8] to [10], wherein the adhesive layer has a laminated structure.

[12] The adhesive sheet according to any one of [8] to [11], which is used for bonding a member having unevenness on a surface having a height difference of 5 μm or more.

[13] The adhesive sheet according to [12], wherein the member is an optical member.

[14] An optical laminate, which is laminated by an adhesive sheet such as [13].

The adhesive of the present invention has excellent unevenness followability, high adhesive force or adhesive retention, and high temperature and high humidity durability. Therefore, even if it is an uneven surface which has been printed or etched, it can be effectively bonded with the adhesive of the present invention, and transparency or color tone can be maintained for a long time.

Hereinafter, the adhesive of the present invention will be described in detail. The description of the constituent elements described below is based on a representative embodiment or a specific example of the present invention, but the present invention is not limited to such an embodiment or a specific example. Moreover, in this specification, the numerical range indicated by "~" The numerical values described later are used as the range of the lower limit and the upper limit.

[Characteristics of the adhesive of the present invention]

The adhesive of the present invention is characterized by containing a cross-linkable acrylic polymer as a main component, and a non-functional acrylic polymer having a weight average molecular weight of 1,000 to 5000 and a Tg of 0 ° C or lower.

[Non-functional acrylic polymer]

The adhesive of the present invention contains a non-functional acrylic polymer. The "non-functional acrylic polymer" herein means a polymer containing only acrylic monomer units having no functional group other than an acrylate group; and an acrylic monomer containing no functional group other than an acrylate group A polymer of a bulk unit and a non-acrylic monomer unit having no functional group. "Monomer unit" means a repeating unit constituting a polymer. The "acrylic monomer" is a compound having a (meth) acrylfluorenyl group. "(Meth) acrylfluorenyl" means acrylfluorenyl or methacrylfluorenyl.

Examples of the acrylic monomer unit having no functional group 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. The carbon number of the hydrocarbon group is preferably 1 to 18, and more preferably 1 to 8.

Specific examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( N-butyl methacrylate, isobutyl (meth) acrylate, third butyl (meth) acrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) acrylic 2 -Ethylhexyl, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate (Meth) acrylic acid Decyl ester, n-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) ) Benzyl acrylate. These may be used individually by 1 type, and may use 2 or more types together.

In the present invention, the term "(meth) acrylic acid" means both "acrylic acid" and "methacrylic acid".

Examples of the non-acrylic monomer having no functional group include a non-functional monomer having a polymerizable vinyl group. The carbon number of the atomic group other than the polymerizable vinyl group of the monomer is preferably 0 to 18, and more preferably 0 to 8.

Specific examples of the non-acrylic monomer having no functional group include ethylene, propylene, and styrene.

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

The non-functional acrylic polymer contained in the adhesive of the present invention is a non-functional acrylic polymer having a weight average molecular weight of 1,000 to 5,000. The weight average molecular weight is preferably 1,000 or more, and more preferably 2,000 or more. It is preferably 5,000 or less, and more preferably 4,000 or less. If the weight average molecular weight is less than 1,000, an adhesive having sufficient unevenness followability and high temperature and high humidity durability cannot be obtained. When the weight average molecular weight exceeds 5000, an adhesive having sufficient unevenness followability and adhesive force cannot be obtained.

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

The non-functional acrylic polymer contained in the adhesive of the present invention preferably has a viscosity of 4800 mPa at 25 ° C. s or less. Here, the viscosity at 25 ° C. is a value measured using a B-type viscometer. The viscosity at 25 ° C of non-functional acrylic polymer is 4800 mPa. s or less, further preferably 3000 mPa. s or less. The viscosity at 25 ° C of the non-functional acrylic polymer is preferably 500 mPa. s or more.

The adhesive (removal of the solvent) of the present invention preferably contains 1.0% by weight or more of the non-functional acrylic polymer, more preferably contains 5.0% by weight or more, more preferably contains 40% by weight or less, and even more preferably contains 30%. % By weight or less. As long as the content of the non-functional acrylic polymer is at least the above-mentioned lower limit value, it is easy to obtain an adhesive having sufficient unevenness followability. If the non-functional acrylic polymer is equal to or less than the above-mentioned upper limit value, it is easy to obtain an adhesive having high temperature and high humidity durability.

[Crosslinkable acrylic polymer]

The adhesive of the present invention contains a crosslinkable acrylic polymer as a main component. The "main component" as used herein means a component of 40% by weight or more of an adhesive (with the solvent removed). The adhesive of the present invention preferably contains 50% by weight or more of the crosslinkable acrylic polymer, and more preferably contains 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 single system does not have an acrylic monomer having a crosslinkable group, and the crosslinkable single system has A monomer having a crosslinkable group. As long as the crosslinkable monomer is polymerizable with a non-crosslinkable acrylic monomer, it may be an acrylic monomer or a non-acrylic monomer, and an acrylic monomer is preferred. Examples of the crosslinkable group include a carboxyl group, a hydroxyl group, an amine group, an epoxy group, a glycidyl group, and the like, and a carboxyl group and a hydroxyl group are preferred.

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. The carbon number of the hydrocarbon group is preferably 1 to 18, and more preferably 1 to 8. This 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 an alkoxy group such as a methoxy group and an ethoxy group.

Specific examples of the (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( N-butyl methacrylate, isobutyl (meth) acrylate, third butyl (meth) acrylate, n-amyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) acrylic 2 -Ethylhexyl, n-octyl (meth) acrylate, 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, octadecyl (meth) acrylate, (meth) acrylic acid Methoxyethyl, ethoxyethyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate. These may be used individually by 1 type, and may use 2 or more types together.

Among these, in terms of adhesiveness, n-butyl acrylate, 2-ethylhexyl acrylate, and methyl acrylate are preferred.

Examples of the crosslinkable monomer unit include a carboxyl group-containing copolymerizable monomer unit, a hydroxyl group-containing copolymerizable monomer unit, an amine group-containing copolymerizable monomer unit, and a glycidyl group-containing copolymerizability. Monomer unit. Examples of the carboxyl group-containing copolymerizable monomer include acrylic acid, methacrylic acid, butenoic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, and glutaric acid. Saturated carboxylic acid or its anhydride.

Examples of the hydroxyl-containing copolymerizable monomer include (methyl) 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2-hydroxypropyl (meth) acrylate. ) Hydroxyalkyl acrylate; (meth) acrylic [(mono, di, or poly) alkanediol] esters; (meth) acrylic mono (diethylene glycol) esters; (meth) acrylic monocaprolactone, etc. (Meth) acrylic lactone; N-hydroxymethyl (meth) acrylamide.

Examples of the amine group-containing copolymerizable monomer include (meth) acrylamide, acrylamide, N, N-dimethyl (meth) acrylamide, and N-third butyl (methyl (Meth) acrylamide, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, third butylaminoethyl (meth) acrylate, and the like.

Examples of the glycidyl group-containing copolymerizable monomer include glycidyl (meth) acrylate.

Among these, it is preferable in terms of less adhesion, crosslinkability, and polymerizability, and further less corrosivity of metals such as tin-doped indium oxide used for transparent conductive films or copper used for electromagnetic wave shielding. It is a hydroxy-containing copolymerizable monomer, more preferably hydroxyalkyl (meth) acrylate, particularly preferably 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate.

In addition, a carboxyl group-containing copolymerizable monomer unit is included as a crosslinkable monomer unit. In the case of yuan, the acidity becomes stronger, so if it comes into contact with a corrosive film such as a tin-doped indium oxide film or a metal film, these films may be corroded. Therefore, when the adhesive of the present invention is applied to such a corrosive object, in terms of corrosion resistance, the content of a carboxyl-containing copolymerizable monomer unit as a crosslinkable monomer unit, It 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. As long as the content of the crosslinkable monomer unit is at least the above-mentioned lower limit, sufficient crosslinking can be achieved, and the swelling resistance or punching processability can be further improved. As long as the content is below the above-mentioned upper limit, it is possible to ensure sufficient Adhesion or unevenness tends to follow performance and anti-curling performance.

The crosslinkable acrylic polymer may have a non-crosslinkable acrylic monomer unit and a monomer unit other than the crosslinkable monomer unit. Examples of other monomers include (meth) acrylonitrile, vinyl acetate, styrene, vinyl chloride, vinylpyrrolidone, vinylpyridine, and acrylamide.

The content of the 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. As long as the content of other monomer units is above the lower limit, physical properties can be easily adjusted, and as long as the content of other monomer units is below the upper limit, yellowing due to deterioration with time can be prevented.

When a monomer is polymerized to synthesize a crosslinkable acrylic polymer, a polymerization initiator is preferably used. As a preferable polymerization initiator which can be used, a polymerization initiator which does not have a repeating unit is mentioned. Examples thereof include azo-based polymerization initiators such as azobisisobutyronitrile and azodivaleronitrile, or benzophenone peroxide and peroxygen. Peroxide based polymerization initiators such as laurel tincture. These polymerization initiators are preferably used, for example, as compared with a high molecular weight azo polymerization initiator having a polymer fragment and an azo group. The molecular weight of the polymerization initiator used in the present invention is preferably 1,000 or less, more preferably 700 or less, and even more preferably 500 or less. The lower limit may be, for example, 100 or more.

The weight average molecular weight of the crosslinkable acrylic polymer is preferably 100,000 or more, more preferably 200,000 or more, still more preferably 300,000 or more, still more preferably 350,000 or more, and still more preferably 2 million or less. It is more preferably 1.5 million or less, still more preferably 1 million or less, and still more preferably 750,000 or less.

[Crosslinking agent]

The adhesive of the present invention contains a crosslinking agent.

唑啉化合物、氮丙啶化合物、金屬螯合化合物、三聚氰胺化合物等。該等交聯劑中，就可容易地將丙烯酸系聚合物交聯的方面而言，較佳為異氰酸酯化合物、環氧化合物。特別是丙烯酸系聚合物僅含有含羥基之共聚合性單體單元作為交聯性單體單元之情形時，就羥基之反應性而言，較佳為使用異氰酸酯化合物。又，丙烯酸系聚合物僅含有含羧基之共聚合性單體單元作為交聯性單體單元之情形時，就羧基之反應性而言，較佳為使用異氰酸酯化合物、環氧化合物、氮丙啶化合物、三聚氰胺化合物，特佳為使用環氧化合物或異氰酸酯化合物。 Examples of the crosslinking agent include isocyanate compounds, epoxy compounds,

An oxazoline compound, an aziridine compound, a metal chelate compound, a melamine compound, and the like. Among these crosslinking agents, an isocyanate compound and an epoxy compound are preferred because they can easily crosslink the acrylic polymer. In particular, when the acrylic polymer contains only a hydroxyl-containing copolymerizable monomer unit as a crosslinkable monomer unit, an isocyanate compound is preferably used in terms of the reactivity of the hydroxyl group. When the acrylic polymer contains only a carboxyl-containing copolymerizable monomer unit as a crosslinkable monomer unit, it is preferable to use an isocyanate compound, an epoxy compound, and aziridine in terms of reactivity of the carboxyl group. As the compound and the melamine compound, 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, and bisphenol. A. Epichlorohydrin type epoxy resin, N, N, N ', N'-tetraglycidyl-m-xylylenediamine, 1,3-bis (N, N-diglycidylamine methyl) cyclohexane, N , N-diglycidyl aniline, N, N-diglycidyl toluidine and other polyfunctional epoxy compounds. Examples of the isocyanate compound include toluene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and the like.

Examples of the crosslinking agent other than the epoxy compound and the isocyanate compound include 2,2'-bishydroxymethylbutanoltri [3- (1-aziridinyl) propionate], 4,4'- Multifunctional aziridine compounds such as bis (ethyleneimine-based amine) diphenylmethane; for example, aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium Metal chelate compounds such as complexes of valence metals with acetoacetone or acetoacetate.

The content of the cross-linking agent is preferably appropriately selected according to the desired adhesive properties. Usually, it is preferably 0.01% by weight or more, more preferably 0.02% by weight or more, more preferably 0.04% by weight or more, more preferably 0.20% by weight or less, and more preferably 0.18% of the adhesive (removing solvent) of the present invention. The weight% or less is more preferably 0.14 weight% or less.

[Other ingredients of adhesive]

The adhesive of the present invention may contain components other than the above. The resin other than the acrylic polymer or the non-functional acrylic polymer as the main component may be a polyester resin, an amine resin, an epoxy resin, or a polyurethane resin in combination. Among them, the addition amount of such a resin is preferably 40% by weight or less of the adhesive (removing the solvent), more preferably 35% by weight or less, and still more preferably 30% by weight or less.

In addition, the adhesive of the present invention may contain light stabilizers such as antioxidants, metal corrosion inhibitors, adhesion-imparting agents, silane coupling agents, ultraviolet absorbers, hindered amine-based compounds, fillers, and ionicity as needed Additives such as liquids. Examples of the antioxidant include a phenol-based antioxidant, an amine-based antioxidant, a lactone-based antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. These antioxidants may be used individually by 1 type, and may use 2 or more types together. As the metal corrosion preventive agent, a benzotriazole-based resin is preferred in terms of the compatibility or the effect of the adhesive. Examples of the adhesion-imparting agent include a rosin-based resin, a terpene-based resin, a terpene-based resin, a benzofuran-indene-based resin, a styrene-based resin, a xylene-based resin, a phenol-based resin, and a petroleum resin. Examples of the silane coupling agent include a mercaptoalkoxysilane compound (for example, a mercapto-substituted alkoxy oligomer). Examples of the ultraviolet absorber include benzotriazole-based compounds and benzophenone-based compounds. Examples of the ionic liquid include an ionic liquid such as a nitrogen-containing onium salt, a sulfur-containing onium salt, or a phosphorus-containing onium salt. Preferably, Japanese Patent Application Laid-Open No. 2011-89138 can be cited in paragraph numbers 0018 to 0028. Documented ionic liquid. The descriptions of paragraph numbers 0018 to 0028 in Japanese Patent Laid-Open No. 2011-89138 are incorporated herein by reference as part of this specification.

When using these additives, the compounding amount is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, more preferably 0.1% by weight or more, and still more preferably 10% by weight of the adhesive (with the solvent removed). Hereinafter, it is more preferably 5% by weight or less, and still more preferably 3% by weight or less.

The paragraph number of Japanese Patent Laid-Open No. 2011-148965 The materials or aspects described in 0021 ~ 0105 can also be used in the present invention, and these records are incorporated herein as part of this specification.

In addition, by using an ionic liquid such as a nitrogen-containing onium salt, a sulfur-containing onium salt, or a phosphorus-containing onium salt, it is preferably selected from the group consisting of the following formulae (A), (B), (C), and (D) As an additive, the ionic salt in the group can make the adhesive have antistatic properties. Ionic salts are liquid or solid at 25 ° C.

[R ¹ in formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, and may also contain heteroatoms. R ² and R ^{3 are the} same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and may also contain hetero atom. However, when the nitrogen atom contains a double bond, there is no R ³ . R ⁴ in formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms, and may also contain a hetero atom. R ⁵ , R ⁶ , and R ^{7 are the} same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and also May contain heteroatoms.

R ⁸ in formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms, and may also contain a hetero atom. R ⁹ , R ¹⁰ , and R ^{11 are the} same or different and represent hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and also May contain heteroatoms. X in formula (D) represents a nitrogen, sulfur, or phosphorus atom, and 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, and may also contain a hetero atom. When X is a sulfur atom, R ^{12 is} absent.

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, and 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-pyrrolline cation, 1-ethyl-2-phenylindole cation, 1, 2-dimethylindole cation, 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, and 1-butyl-3-methyl Imidazolium 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-dimethyl Imidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium 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-dihydropyrimidine Pyridinium 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 cations and the like.

Examples of the cation represented by the formula (C) include a pyrazolium cation, a pyrazolinium cation, and the like. 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 trialkylphosphonium cation, a tetraalkylphosphonium cation, or an alkyl group or an alkoxy group substituted with a part of the alkyl group, and further an epoxy group. Specific examples thereof include tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, Trimethyldecyl ammonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyl trimethylammonium cation, N, N-dimethyl -N, N-dipropylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl-N, N-dihexylammonium cation, trimethylsulfonium Cation, triethylphosphonium cation, tributylphosphonium cation, trihexylphosphonium cation, diethylmethylphosphonium cation, dibutylethylphosphonium cation, dimethyldecylphosphonium cation, tetramethylphosphonium cation, tetramethylphosphonium Ethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecane Phosphonium cation, a diallyl dimethyl ammonium cation.

On the other hand, as an anion component, as long as it becomes an ionic liquid are satisfied, not particularly limited, for example, may be ^{used: 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. Among these, in order to obtain an ionic compound having a low melting point, it is particularly preferable to use an anion component containing a fluorine atom.

The ionic salt may be a commercially available one or may be appropriately synthesized. The method for synthesizing the ionic salt in a liquid state is not particularly limited as long as it is a method for obtaining a target ionic liquid. For example, the document "Ionic Liquid-The Forefront of Development and the Future-" [CMC Publishing (Share) issue] as described in the halide method, hydroxide method, ester method, error method, and neutralization method, a method based on it, or a method combining these with a common method.

[Application of adhesive]

The adhesive of the present invention can be directly applied to those who want to adhere. The application method is not particularly limited. For example, it can be dissolved in a solvent to make a solution, and then applied and dried (solution method), or it can be formed into a sheet in advance and overlapped (sheet method). When it is applied as a solution, it can be coated on a release film and then contacted with the object to be adhered (transfer method); it can also be laminated with a release film with different release properties and finished into After the sheet-like shape of the release film is brought into contact with the object to be adhered on the adhesive layer from which the release film is peeled off (adhesive sheet method).

烷、乙腈、四氫呋喃、二乙二醇二甲醚、二甲基亞碸、N-甲基吡咯啶酮、二甲基甲醯胺等。塗佈溶液後，可藉由於高溫或減壓下去除溶劑而製成黏著劑層。 When the adhesive is applied as a solution and applied, as the solvent, for example, methyl ethyl ketone, ethyl acetate, toluene, xylene, acetone, benzene, and dioxane can be used.

Alkanes, acetonitrile, tetrahydrofuran, diethylene glycol dimethyl ether, dimethyl sulfene, N-methylpyrrolidone, dimethylformamide and the like. After applying the solution, the adhesive layer can be made by removing the solvent due to high temperature or reduced pressure.

[Thickness of adhesive layer]

When using the adhesive of the present invention to form an adhesive layer, the thickness of the adhesive layer is not particularly limited.

Usually, it is preferably 50 μm or more, more preferably 100 μm or more, and still more preferably 500 μm or less. As long as the thickness of the adhesive layer is greater than or equal to the above-mentioned lower limit value, there is a tendency that sufficient followability to unevenness can be obtained, and problems such as occurrence of abnormalities such as bubbles are unlikely to occur. In addition, as long as the thickness of the adhesive layer is equal to or less than the above-mentioned upper limit value, there is a tendency that the light transmittance of the adhesive layer is reduced, or the problem of the exposure of the adhesive is difficult to occur during the punching process of the adhesive.

[Adhesive layer with laminated structure]

The adhesive layer may have a laminated structure of two or more layers. In the case of having a multilayer structure of two or more layers, at least one layer must be an adhesive layer that satisfies the conditions of the present invention. For example, specific examples include: a two-layer laminate structure including a layer that satisfies the conditions of the present invention / a layer that does not meet the conditions of the present invention; or a layer that satisfies the conditions of the present invention / another layer that satisfies the conditions of the present invention Or a three-layer laminated structure including 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. At this time, the thickness of the adhesive layer that satisfies the conditions of the present invention is preferably a thickness having the above-mentioned preferred range. In the case where the 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 preferably 50% of the total thickness of the adhesive layer. The above is more preferably 70% or more, and may be set to 85% or more.

The adhesive layer which satisfies the conditions of the present invention is preferably configured so as to be in direct contact with an adhesion target having unevenness. When the adhesive layer has a laminated structure of a layer that satisfies the conditions of the present invention and a layer that does not meet the conditions of the present invention, it is preferably a cross-linkable acrylic resin contained as a main component in the layer that satisfies the conditions of the present invention The weight average molecular weight of the cross-linkable acrylic polymer as a main component contained in the layer which does not satisfy the conditions of the present invention is larger than the weight average molecular weight of the polymer. For example, the weight average molecular weight of the latter can be increased by 200,000 or more, or 400,000 or more.

[Adhesive sheet]

The adhesive of the present invention can be formed into a sheet to form an adhesive sheet. The adhesive sheet can be produced, for example, by dissolving an adhesive in a solvent and removing the solvent after coating. The coating method can be appropriately selected from the group consisting of doctor blade coating, microrod coating, air knife coating, reverse roll coating, reverse gravure coating, multidirectional gravure coating, slit extrusion coating, and curtain coating. Curtain coating, etc.

The adhesive sheet of the present invention can be obtained, for example, by preparing a release film provided with a release agent layer on a substrate such as a polymer film, applying the adhesive coating solution of the present invention to the release agent layer, and performing dry. As shown in FIG. 1, the release sheet is preferably one having a structure in which two release films 114 provided with a release agent layer 115 on the base material 116 are sandwiched above and below the adhesive layer 112. The adhesive sheet of the present invention having such a structure can be obtained by applying an adhesive coating solution on the release layer of a first release film provided with a release agent layer on a polymer film, and drying the adhesive film. The release layer of the second release film including a release agent layer having a peeling force different from that of the first release film is bonded and pressure-bonded to the adhesive. Level.

When the peeling force of the first peeling film and the second peeling film are close to each other, when the peeling film on the light peeling force side is peeled off, the peeling phenomenon of the peeling film on the peeling force side of the adhesive is raised. Therefore, the peeling force of the peeling film on the heavy peeling force side is preferably 0.5 N / 50 mm to 1.5 N / 50 mm, and the peeling force of the peeling film on the light peeling force side is preferably 0.01 N / 50 mm to 0.4 N / 50. mm. Further, the value of the heavy peeling force ÷ light peeling force is preferably 1.5 or more, and more preferably 2.0 or more.

In this case, when the difference in the peeling force between the two release films is maintained, an adhesive coating liquid may be applied to the second release film in advance, and then the first release film may be bonded and pressure-bonded.

The shape of the adhesive sheet may be a sheet, or it may be rolled into a roll.

If an adhesive sheet is used, the steps of applying and drying the adhesive in the bonding stage are not necessary, and the adhesive sheet can be adhered by simply laminating and pressing the adhesive sheet between two adherends, which is convenient. That is, the first adhesion target, the adhesive sheet, and the second adhesion target are laminated in this order, and the obtained laminated body is pressurized, so that the two adhesion targets can be easily adhered.

[Adhesive object with adhesive layer]

As shown in FIG. 2, the adhesive of the present invention is laminated on the surface of the adhered object 111 to form an adhesive layer 112, whereby an adhered object 110 with an adhesive layer can be manufactured. As a method of applying an adhesive to the surface of an adhered object, the solution method and the sheet method described above can be used. As shown in FIG. 3, the object to be adhered with the adhesive layer is superimposed and pressurized so that the side of the adhesive layer 112 contacts the object 113 to be adhered to the object 111 to be adhered, thereby being easily adhered to the object. Stick to the object.

In addition, after peeling off the release film 114 on one side of the adhesive sheet using the adhesive of the present invention shown in FIG. 1, as shown in FIG. 4, the adhesive object 111 is pressure-bonded to the adhesive layer 112 to manufacture the accessory. Adhesive object of the adhesive layer. In this case, in order to prevent the adhesive from sticking to the object insignificantly or deteriorating due to exposure to the air, the release film is preferably peeled as soon as possible immediately before bonding.

Furthermore, when the adhesive agent of the present invention is formed into a sheet shape to form an adhesive sheet, an adhesive object with an adhesive layer can also be produced by directly applying the adhesive object by applying the adhesive film to the release film, for convenience. , Its manufacturing method can be used separately.

A known surface treatment such as a corona treatment or a plasma treatment is performed on the bonding surface of the object to be bonded, thereby further improving the adhesion between the adhesive layer and the object to be bonded.

The shape of such an object to be adhered with an adhesive may be a sheet shape or a roll shape.

As shown in FIG. 3, the object to be adhered with the adhesive layer is superimposed and pressed so that the second adhesive object 113 to be adhered contacts and peels off the adhesive layer 112 of the release film, thereby allowing easy adhesion. Close the second adhesion object 113. In this case, in order to prevent the adhesive from sticking to the object insignificantly or deteriorating due to exposure to the air, the release film is preferably peeled as soon as possible immediately before bonding.

As a mechanism for suppressing such a situation, as shown in FIG. 4, a state in which a release film 114 is further formed on the adhesive layer 112 in advance can be cited as a preferable example. The release film 114 preferably includes a base material 116 and a release agent layer 115. this In this case, lamination is performed so that the release agent layer 115 side of the release film contacts the surface of the adhesive layer 112. In particular, when it is made into a roll shape, it is preferred to apply such a release film and roll it up in advance. When in use, the release film is peeled off and the adhered object with an adhesive layer is bonded to the second adhered object. .

Furthermore, the adhesive layer may be formed on both surfaces of the object to be adhered in advance. The above-mentioned release film may be further formed on the adhesive layer formed on both surfaces. As a specific example of such a state, the state shown in FIG. 5 can be mentioned. In use, for example, the adhesive layer exposed by peeling the release film on one side is superimposed on the object to be adhered, and then the adhesive layer exposed by peeling the other surface of the peeling film is superimposed on another object to be adhered, and the whole is pressed. This can be used for adhesion.

As the base material for a release film, for example, various polymer films can be used. However, in terms of surface smoothness or processability, polyethylene terephthalate is particularly preferred. As the release agent constituting the release agent layer, for example, a general-purpose addition-type or condensation-type silicone release agent or a compound containing a long-chain alkyl group can be used. In particular, it is preferred to use a highly reactive addition-molded silicone release agent. Specific examples of the polysiloxane-based release agent include BY24-4527 and SD-7220 manufactured by Dow Corning Toray Silicone or KS-3600, KS-774, and X62-2600 manufactured by Shin-Etsu Chemical Industry Co., Ltd. Wait. In addition, it is preferable that the polysiloxane-based release agent contains a polymer as an organosilicon compound having SiO ₂ units and (CH ₃ ) ₃ SiO _1/2 units or CH ₂ = CH (CH ₃ ) SiO _1/2 units. Silicone resin. Specific examples of the silicone resin include BY24-843, SD-7292, and SHF-1404 manufactured by Dow Corning Toray Silicone, and KS-3800 and X92-183 manufactured by Shin-Etsu Chemical Industry Co., Ltd.

[Adhesive object]

There is no particular limitation on an adherend to be adhered using the adhesive of the present invention. For example, glass, a film, etc. are mentioned. As long as the adhesive of the present invention is used, adhesion with lower haze and higher transparency can be achieved, so it can be better used for adhesion of surface protection boards or touch panel modules of display devices; surface protection boards and Adhesion of image display module, or touch panel module and image display module.

Examples of the surface protection plate include a glass plate or a resin plate subjected to frame printing, and the material is not particularly limited as long as the penetrability is ensured. Specifically, in addition to inorganic materials such as soda glass, alkali-free glass, and strengthened glass, transparent resins such as polyethylene terephthalate resin, polycarbonate resin, and polymethyl methacrylate resin are preferred.

Examples of the adhered object of the touch panel module include a sensing glass or a sensing film that has been subjected to a conductive treatment, a protective film on the conductive layer and a conductive glass, or a sensing glass that has been subjected to a conductive treatment. The glass or film corresponding to the opposite side of the sensing film, and the hard coating on the surface. Examples of the film subjected to the conductive treatment include polyethylene terephthalate resin, polycarbonate resin, and cycloolefin resin.

Examples of the object to be adhered to the image display module include an optical film and a display panel. It is preferable to provide the optical laminate by bonding these using the adhesive of the present invention. Examples of the optical film include a retardation film (optical compensation film) having optical anisotropy, a retardation in a specific in-plane direction, and a retardation in a specific thickness direction; and a polarized light formed to protect polarizers Sub-protective film (also referred to as a polarizer protective film); polarizer base material that functions as a support for polarizers in polarizers; anti-reflection films that suppress the reflection of light incident from the outside. 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 propionate butyrate Halogenated cellulose such as cellulose; cycloolefin resin and the like. Examples of commercially available resin materials that can be used as a retardation film include ARTON (manufactured by JSR), ZEONOR (manufactured by ZEON, Japan), and the like. On the other hand, examples of the display panel include glass.

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 (electro luminescence) panel).

Since the surface protective plate or touch panel module and image display module can be effectively adhered by using the adhesive of the present invention, in addition to being able to better manufacture a fixed image display device, it can also be better manufactured as an action Mobile phones, smart phones, tablet terminals, and mobile computers.

The adhesive of the present invention is particularly suitable for bonding members having an uneven surface because of its excellent unevenness followability. That is, the adhesive of the present invention can be preferably used for the bonding of members having unevenness on the surface and members having no unevenness on the surface; the same kind of members having unevenness on the surface; Lamination of members with irregularities. The "member having unevenness on the surface" herein refers to a member having unevenness on the surface of a member to be bonded, whose unevenness (step difference) is 5 μm or more. As a specific example, a frame protection surface protection plate or the like can be cited as a reason. Think example. According to the necessity of decoration or concealment, the printing step of the surface protection plate has the following tendency: from 10 μm to 15 μm to 60 μm in recent years, the adhesive of the present invention has excellent unevenness followability and prevents Residual bubbles during lamination, and the display device after lamination becomes high temperature even after long-term continuous use or outdoor use, or the panel is placed in high humidity due to use in a high humidity environment. In this case, it can also prevent the generation of air bubbles and maintain a stable display function. That is, even when exposed to high temperature and high humidity for a long time, the adhesive of the present invention can prevent the following situations: the change of the color tone of the display, the whitening constantly, the distortion or the uneven display due to the generation of air bubbles.

[Example]

The characteristics of the present invention will be described more specifically with reference to the following examples and comparative examples. The materials, usage amounts, proportions, processing contents, processing procedures, and the like shown in the following examples can be appropriately changed as long as they do not depart from the spirit of the present invention. Therefore, the scope of the present invention should not be limitedly interpreted by the specific examples shown below. In addition, "part" and "%" in an Example mean "weight part" and "weight%" unless there is particular notice. The weight-average molecular weight M _w is a sample in which THF (tetrahydrofuran) is dissolved using a gel permeation chromatography method (pump: PU-980, detector: RI-2031Plus, manufactured by JASCO Corporation), and The value was determined by the polystyrene standard. The glass transition temperature (Tg) was measured using a DSC (thermogravimetric differential thermal synchronization measurement device) manufactured by SII. The viscosity at 25 ° C was measured using a type B viscometer manufactured by TOKIMEC.

(1) Preparation of adhesive solution

100 parts by weight of an acrylic polymer having a carboxyl group (SK-2094 manufactured by Shoken Chemical Co., Ltd.) and an epoxy-based crosslinking agent (Shoken 0.1 parts by weight of E-5XM manufactured by Chemical Co., Ltd., 0.15 parts by weight of silane coupling agent (C-50 manufactured by Soken Chemical Co., Ltd.), and 0.01 parts by weight of metal corrosion inhibitor (M produced by Soken Research Chemical Co., Ltd.) And 5.0 parts by weight of the low-molecular-weight acrylic polymer described in Table 1, thereby preparing each adhesive solution of Examples 1 to 4 and Comparative Examples 1 to 5. In Comparative Example 1, a low molecular weight acrylic polymer was not added. In addition, the low-molecular-weight acrylic polymers added in Examples 1 to 4 and Comparative Examples 2 to 5 are all liquids at 25 ° C, the non-volatile content is 98% or more, and the specific gravity is in the range of 1.02 to 1.12. Refraction The ratio is 1.46 to 1.47, and it is a 100% polymer of a cross-linkable acrylic monomer.

(2) Manufacturing of adhesive sheet

Using the adhesive solutions of Examples 1 to 4 and Comparative Examples 1 to 5 prepared in (1), each of the adhesive sheets of Examples 1A to 4A and Comparative Examples 1A to 5A was manufactured in the following order.

A release film having a release agent layer on a PET (polyethylene terephthalate) film [manufactured by Mitsubishi Resins Co., Ltd., MRV # 50] was prepared as a first release sheet, and the first release sheet was prepared on the first release sheet. On the release agent layer, the adhesive solution prepared in (1) was applied by doctor blade application. As a second release sheet, a release film [manufactured by Teijin Dupont Films (strand), A50 # 50] having a release agent layer on a PET film was prepared. After heating at 40 ° C for 2 minutes, it was further heated at 110 ° C for 2 minutes. Thus, an adhesive sheet having an adhesive layer having a thickness shown in Table 2 between the first release sheet and the second release sheet was produced.

(3) Adhesion test

The adhesive sheet manufactured in (2) was cut to a size of 25 mm × 100 mm, and the adhesive layer exposed by peeling the second release sheet was attached to the surface of a clean glass plate, and pressed back and forth with a 2 kg pressure roller Take 2 times. Immediately after crimping and 24 hours after crimping, a TENSILON tensile tester [Automatic Stereo Mapping Machine manufactured by Shimadzu Corporation] was used to measure the 180-degree peeling method specified by JIS-Z-0237 (Peeling method) The adhesive force when the adhesive layer was peeled from the glass plate at a tensile speed of 300 mm / min. In addition, the residue of the paste on the glass surface after peeling was evaluated by the following 4 levels. The results are shown in Table 2.

A: No paste residue

B: No paste residue (only some paste residue on the edge or beyond)

C: Paste residue as a whole

D: Paste residue during measurement

It is clear from Table 2 that Examples 1A to 4A are not inferior to Comparative Example 1A in which a non-functional acrylic polymer is not added. This case indicates that even if a nonfunctional acrylic polymer is added according to the present invention, the adhesive properties are not affected. On the other hand, the adhesive force of Comparative Example 2A or Comparative Example 3A after 24 hours after compression bonding was inferior to that of Examples 1A to 4A.

(4) Holding force test

The adhesive sheet manufactured in (2) was cut into a size of 25 mm × 100 mm, and the adhesive layer exposed by peeling the second release sheet was attached to the surface of a clean SUS (Steel Use Stainless) board. The holding force test specified in JIS-Z-0237: 2000 was performed, and evaluation was performed using the following criteria. The results are shown in Table 2.

A: No offset

C: with offset

As shown in Table 2, no offset was found in the samples.

(5) High temperature and high humidity durability test

Using each of the adhesive sheets of Examples 1 to 4 and Comparative Examples 1 to 4 manufactured in (2), the adhesive layer exposed by peeling the second release sheet was made with 100 μm PET [manufactured by Toyobo Corporation, Cosmosine A4300] Laminating was followed by using a pressure-bonding roller to adhere the adhesive layer exposed by peeling the first release sheet to glass [Slide Glass S9111 manufactured by Matsuna Glass Industry Co., Ltd.] to prepare Example 1B ~ Samples of 4B and Comparative Examples 1B to 4B. The total transmittance (Tt) and haze (Hz) of each sample were measured using a turbidimeter [Haze Meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd., and a color difference meter [Spectro Color Meter SE2000 manufactured by Nippon Denshoku Industries Co., Ltd.] ] Measure the brightness (L *) and chromaticity (a *, b *). Thereafter, each sample was placed in an oven set at 85 ° C. and a relative humidity of 85%, and was taken out after 250 hours. After 30 minutes, the haze (Hz), total light transmittance (Tt), and brightness (L *), Chromaticity (a *, b *). The haze (Hz) was also measured 24 hours after taking out. The results are shown in Table 3 below.

As shown in Table 3, the high temperature and high humidity durability of Examples 1B to 4B were high. In contrast, the unprocessed Hz value of Comparative Example 3B is high.

(6) Bump followability test 1

Using each of the adhesive sheets of Examples 1 to 4 and Comparative Examples 1 to 5 manufactured in (2), samples of Examples 1C to 4C and Comparative Examples 1C to 5C were manufactured according to the following procedures, respectively.

Printing was performed on one side of glass (thickness: about 0.9 mm) so as to form unevenness with a height difference of 10 μm, to obtain a glass with unevenness. On the pressure-sensitive adhesive layer exposed by peeling the second release sheet of the pressure-sensitive adhesive sheet manufactured in (2), non-concavo-convex polyethylene terephthalate (thickness: 188 μm) was bonded, and then a pressure roller was used to apply The uneven surface of the uneven-attached glass is bonded to the adhesive layer exposed by peeling the first release sheet. In a pressure degassing apparatus (YK-350S manufactured by Kurihara Manufacturing Co., Ltd.) at 40 ° C, a pressure of 0.5 MPa was applied to the obtained transparent laminated body for 10 minutes. Thereafter, the occurrence of bubbles was observed with a microscope (magnification: 25 times), and the degree of adhesion of the glass with unevenness was evaluated by the following criteria. The results are shown in Table 4.

A: Compared with Comparative Example 1, there are fewer bubbles

B: Compared with Comparative Example 1, there are fewer bubbles

C: The bubbles remaining on the uneven printing step are the same as or more than those of Comparative Example 1.

As shown in Table 4, all the samples of the examples showed good unevenness followability. On the other hand, in Comparative Examples 2C to 5C, no improvement in unevenness followability was found.

(7) Concave-convex follow-up test 2

In the test of (6), the treatment in the pressure defoaming device was changed to 30 minutes at 60 ° C and 0.6 MPa, and then it was left to stand at 80 ° C for 1 day. Test (Delay Bubble Test). Table 4 shows the results of the evaluation using the criteria of (6).

As shown in Table 4, the samples of the examples all showed good results.

(8) Addition amount change test

Examples 4D-1, 4D-2, and 4D-3 were prepared by changing the addition amount of the non-functional acrylic polymer in Example 4 to 4.0 parts by weight, 8.0 parts by weight, and 24.0 parts by weight. sample. In the samples of Examples 4D-1, 4D-2, and 4D-3, the thickness of the adhesive layer was set to 75 μm. In addition, a sample of Comparative Example 1D-1 in which the thickness of the adhesive layer of Comparative Example 1 was changed to 75 μm was also produced. For each of these samples, the adhesion test of (3) was performed. The results are shown in Table 5.

For each sample, the adhesive layer was changed to 175 μm, and the unevenness followability test 3 was performed in the following procedure. Printing was performed on one side of glass (thickness: about 0.9 mm) so as to form unevenness with a height difference of 30 μm, to obtain a glass with unevenness. Then, the adhesive layer exposed by peeling off the second release sheet of the sample adhesive sheet was bonded to glass [Slide Glass S9111 manufactured by Matsuna Glass Industry Co., Ltd.] to obtain a glass with an adhesive layer. Then, using a vacuum laminator [V-SE160H manufactured by CLIMB PRODUCTS Co., Ltd.], under an environment with a vacuum of 100 Pa and a temperature of 30 ° C, a pressure of 0.6 MPa for 30 seconds was applied, and an adhesive layer was attached. The adhesive layer exposed by peeling the first release sheet of glass is bonded to the uneven surface of the glass with unevenness. In a pressure defoaming device [YK-350S manufactured by Kurihara Manufacturing Co., Ltd.] at 50 ° C, a pressure of 0.5 MPa was applied to the obtained transparent laminated body for 20 minutes. Thereafter, the occurrence of bubbles was observed using a microscope (magnification: 25 times), whereby the degree of adhesion of the glass with unevenness was evaluated using the same criteria as in (6).

In addition, as the bump followability test 4, the same procedure as in (7) was followed, and The transparent laminated body bonded according to the same procedure as (8) was evaluated using the same criteria as (7). The results are shown in Table 5.

As shown in Table 5, even if the cross-linking agent of the non-functional acrylic polymer was changed, the adhesion of Examples 4D-1, 4D-2, and 4D-3 was good, and the unevenness followability was improved. In particular, the unevenness followability of Example 4D-3 was significantly improved (the evaluation was set to AA).

(9) Cross-linking agent change test

Manufactured by changing the cross-linking agent in Example 4 and Comparative Example 1 to epoxy-based cross-linking agent [E-5C manufactured by Soken Chemical Co., Ltd.] and changing the thickness of the adhesive layer to 75 μm Samples of Example 4D-4 and Comparative Example 1D-1. For each of these samples, the adhesion test of (3) was performed. Further, the thickness of the 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 adhesion of Example 4D-4 was good, and the unevenness followability was improved.

(10) Two-layer test of adhesive layer [Synthesis of Adhesive Solution of the First Adhesive Layer]

A reaction device including a stirrer, a thermometer, a reflux cooler, a dropping device, and a nitrogen introduction tube was filled with nitrogen, and 105 parts by weight of ethyl acetate as a solvent was added. Then, in the reaction device, 55 parts by weight of methyl acrylate, 45 parts by weight of 2-ethylhexyl acrylate, and 4 parts by weight of acrylic acid were added to ethyl acetate so that the monomer concentration became about 50% by weight. -5.0 parts by weight of hydroxybutyl ester, 0.24 parts by weight of azobisisobutyronitrile (hereinafter, referred to as "AIBN, azobisisobutyronitrile") as a starter. Thereafter, while stirring at 50 ° C. for 8 hours while stirring in a nitrogen stream, the polymerization reaction was stopped by rapid cooling using an ice water bath to obtain an acrylate copolymer solution having a weight average molecular weight Mw of 1 million.

With respect to 100 parts by weight of the solid content of the copolymer solution, the hexamethylene diisocyanate-based trifunctional adduct used as a crosslinking agent was diluted with ethyl acetate so as to be a solution having a concentration of 35% by weight [Asahi Kasei P301-75E manufactured by the company] 0.4 parts by weight, and further 5.0 parts by weight of the low-molecular-weight acrylic polymer used in Example 1 described in Table 1, each adhesive solution E-1 used in Example 5 was obtained. Furthermore, the adhesive solution E- used in Comparative Example 6 In 2, no low molecular weight acrylic polymer was added.

[Synthesis of the adhesive solution of the second adhesive layer]

Except that the amount of AIBN used was changed to 0.12 parts by weight, an acrylate copolymer solution having a weight average molecular weight Mw 1.5 million was obtained in the same manner as the method for synthesizing the adhesive solution of the first adhesive layer. With respect to 100 parts by weight of the solid content of the copolymer solution, 0.4 part by weight of hexamethylene diisocyanate trifunctional adduct [P301-75E manufactured by Asahi Kasei Co., Ltd.] as a cross-linking agent was added and used Ethyl acetate was diluted so as to become a solution having a concentration of 25% by weight to obtain a solution of the adhesive F-1.

[Production of double-sided adhesive sheet]

A release film [38 μ RL-07 (2) manufactured by Oji Special Paper Co., Ltd.] provided with a release agent layer on a PET film was prepared as a first release sheet, and coated with a doctor blade, and then applied to the first release sheet. The adhesive solution (E-1 or E-2) for the first adhesive layer was applied on the release agent layer, and heated at 100 ° C for 3 minutes to form the first adhesive layer. Thus, Example 5 and Comparative Example 6 were obtained. Use the first adhesive sheet. In addition, a release film [38 μ RL-07 (L) manufactured by Oji Special Paper Co., Ltd.] having a release agent layer having higher releasability than the first release sheet on a PET film was prepared as a second release sheet, and Apply a doctor blade, and apply the solution of the second adhesive layer solution F-1 to the release agent layer of the second release sheet, and heat at 100 ° C for 3 minutes to form a second adhesive layer, and A second adhesive sheet was obtained. Then, the first adhesive sheet and the second adhesive sheet were superimposed so that the first adhesive layer and the second adhesive layer were in contact with each other, and the pressure-bonding was performed to produce Table 7 between the first release sheet and the second release sheet. The adhesive sheet of the adhesive layer of the thickness shown was obtained, and the adhesive sheet of Example 5 and Comparative Example 6 was obtained.

Using each of the adhesive sheets of Example 5 and Comparative Example 6 produced as described above, samples of Example 5D and Comparative Example 6D were produced according to the following procedures.

The unevenness followability test 3 was performed in the following procedure. Printing was performed on one side of glass (thickness: about 0.9 mm) so as to form unevenness with a height difference of 30 μm, to obtain a glass with unevenness. Then, the second adhesive layer exposed by peeling off the second release sheet of the adhesive sheet of the sample was bonded to glass [Slide Glass S9111 manufactured by Matsuna Glass Industry Co., Ltd.] to obtain a glass with an adhesive layer. Then, using a vacuum laminator [V-SE160H manufactured by CLIMB PRODUCTS Co., Ltd.], under an environment with a vacuum of 100 Pa and a temperature of 30 ° C, a pressure of 0.6 MPa for 30 seconds was applied, and an adhesive layer was attached. The first adhesive layer exposed by peeling the first release sheet of glass is bonded to the uneven surface of the glass with unevenness. In a pressure defoaming device [YK-350S manufactured by Kurihara Manufacturing Co., Ltd.] at 50 ° C, a pressure of 0.5 MPa was applied to the obtained transparent laminated body for 20 minutes. Thereafter, the occurrence of bubbles was observed with a microscope (magnification: 25 times), and the degree of adhesion of the glass with unevenness was evaluated by the following criteria.

A: Compared with Comparative Example 6, there are fewer bubbles

B: Compared with Comparative Example 6, there are fewer bubbles

C: The air bubbles remaining on the uneven portion of the printing step are the same as or more than that of Comparative Example 6.

In addition, as the unevenness followability test 4, the transparent laminated body adhered in the same order as (8) was evaluated using the same standard as described above. The results are shown in Table 5.

As shown in Table 7, even if the adhesive layer was changed to two layers, the adhesion of Example 5D The focus is also good, and the unevenness followability is improved.

[Industrial availability]

The adhesive of the present invention is excellent in followability of unevenness, has high adhesive force or adhesive holding force, and has excellent high temperature, high humidity durability. Therefore, even if it is an uneven surface which has been printed or etched, it can be effectively bonded with the adhesive of the present invention, and transparency or color tone can be maintained for a long time. Therefore, the adhesive of the present invention can be effectively applied to the adhesion of various articles such as display devices which are necessary for the adhesion of films or panels, and has high industrial applicability.

110‧‧‧ Adhesive object with adhesive layer

111‧‧‧ Adhesive object

112‧‧‧Adhesive layer

113‧‧‧Second adhesion object

114‧‧‧ peeling film

115‧‧‧ peeling agent layer

116‧‧‧ Substrate

FIG. 1 is a cross-sectional view showing an embodiment of an adhesive sheet having a release film on both sides.

FIG. 2 is a cross-sectional view showing an embodiment of an adhesion target with an adhesive layer.

FIG. 3 is a cross-sectional view showing an embodiment in which one of two adhered objects is bonded by an adhesive layer.

FIG. 4 is a cross-sectional view showing an embodiment of an adhesion target with an adhesive layer having a release film.

FIG. 5 is a cross-sectional view showing an embodiment of an adhesion target having an adhesive layer having a release film on both sides.

112‧‧‧Adhesive layer

114‧‧‧ peeling film

115‧‧‧ peeling agent layer

116‧‧‧ Substrate

Claims (13)

An adhesive characterized by containing a cross-linkable acrylic polymer as a main component, a cross-linking agent, and a non-functional acrylic polymer having a weight average molecular weight of 1700 to 4000 and a Tg of 0 ° C or lower. 40% by weight. The adhesive of claim 1, wherein the content of the carboxyl-containing copolymerizable monomer unit of the crosslinkable acrylic polymer is less than 0.5% by weight. As the adhesive of claim 2, wherein the viscosity at 25 ° C of the non-functional acrylic polymer is 4800 mPa. s or less. The adhesive of claim 2, wherein the weight average molecular weight of the crosslinkable acrylic polymer is 100,000 to 2 million. The adhesive according to claim 4, wherein the crosslinkable acrylic polymer is polymerized using a polymerization initiator without repeating units, and has a weight average molecular weight of 350,000 to 750,000. The adhesive according to any one of claims 1 to 5, wherein the crosslinking agent is an epoxy-based crosslinking agent. An adhesive sheet having an adhesive layer made of the adhesive according to any one of claims 1 to 6. The adhesive sheet according to claim 7, wherein a release sheet is formed on at least one side of the adhesive layer. The adhesive sheet according to claim 7, wherein a release sheet is formed on both sides of the adhesive layer. The adhesive sheet according to any one of claims 7 to 9, wherein the adhesive layer has a laminated structure. The pressure-sensitive adhesive sheet according to any one of claims 7 to 9 is used for bonding a member having unevenness on a surface of 5 μm or more. The adhesive sheet according to claim 11, wherein the above-mentioned member is an optical member. An optical laminated body is formed by laminating an adhesive sheet according to claim 12.