JPWO2019198545A1 - adhesive - Google Patents

Abstract

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to exhibit surface tackiness to improve temporary adhesion, and further, it is possible to exhibit excellent adhesive force by enhancing adhesion even after temporary attachment, and it is excellent in transparency, particularly optical. Provided is an adhesive capable of suppressing deterioration of brightness when used for bonding films.
The present invention contains a thermoplastic resin, a reactive diluent (A) and a photoreactive initiator, and the reactive diluent (A) is JIS K 6851-1: 1999 when used for adhesion between PETs. This is an adhesive having a 90-degree peel-off adhesive strength of 5.5 N / 25 mm or more measured in accordance with the above.

Description

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to exhibit surface tackiness to improve temporary adhesion, and further, it is possible to exhibit excellent adhesive force by enhancing adhesion even after temporary attachment, and it is excellent in transparency, particularly optical. The present invention relates to an adhesive capable of suppressing brightness deterioration when used for bonding films.

Conventionally, an adhesive containing a large amount of solvent has been used for bonding plastic films and the like in order to make the amount of the adhesive applied uniform, but such an adhesive volatilizes a large amount of solvent when it dries. As a result, problems of toxicity, work safety and environmental pollution have arisen.

For this reason, solvent-free adhesives that do not use a solvent are attracting attention. As such a solvent-free adhesive, an active energy ray-curable adhesive that is cured by active energy rays such as ultraviolet rays and electron beams is widely used. In particular, the active energy ray-curable adhesive is widely used for bonding optical films used in liquid crystal displays and organic EL displays.

Further, in recent years, in order to reduce curing shrinkage, improve yield, and fix a very small area, an active energy ray-curable adhesive is applied, and then a small amount of active energy ray is irradiated to temporarily fix the adhesive, and then further active. A two-stage curing system that irradiates energy rays to perform main curing is drawing attention. In such two-stage curing, adhesion is enhanced by irradiating active energy rays after the first-stage temporary fixing, when an adhesive is applied, when the first-stage temporary fixing is performed, and the present. It is required that the resin component in the adhesive is not significantly deformed at any time when it is cured.

As an active energy ray-curable adhesive used for adhering an optical film, for example, Patent Document 1 describes an adhesive containing a radical polymerizable compound having an active methylene group and a radical polymerization initiator having a hydrogen abstraction action. ing. However, although the adhesive described in Patent Document 1 has adhesive strength to a polarizing plate, the adhesive strength becomes insufficient when used for bonding with other optical films, or when two-stage curing is performed. There was a problem that the adhesiveness was not enhanced and sufficient adhesiveness could not be exhibited.
Further, Patent Document 2 includes a pressure-sensitive adhesive containing a (meth) acrylic polymer containing an aromatic ring-containing (meth) acrylic monomer as a monomer, and light-diffusing fine particles having a refractive index lower than that of the pressure-sensitive adhesive. Adhesives are listed. However, the adhesive described in Patent Document 2 has a problem that it has a low adhesive force in a small area and is not suitable for bonding optical films that are required to be fixed in a very small area.
Further, Patent Document 3 describes an adhesive made of a siloxane polymer, but since the resin is flexible, there is a problem that the resin is deformed at the time of adhesion and adversely affects the optical characteristics.

Japanese Unexamined Patent Publication No. 2014-132092 Japanese Unexamined Patent Publication No. 2014-224964 Special Table 2009-507959

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to exhibit surface tackiness to improve temporary adhesion, and further, it is possible to exhibit excellent adhesive force by enhancing adhesion even after temporary attachment, and it is excellent in transparency, particularly optical. An object of the present invention is to provide an adhesive capable of suppressing deterioration of brightness when used for bonding films.

The present invention contains a thermoplastic resin, a reactive diluent (A) and a photoreactive initiator, and the reactive diluent (A) is JIS K 6851-1: 1999 when used for adhesion between PETs. This is an adhesive having a 90-degree peel-off adhesive strength of 5.5 N / 25 mm or more measured in accordance with the above.
The present invention will be described in detail below.

By using a thermoplastic resin, a reactive diluent (A) satisfying predetermined physical properties, and a photoreaction initiator in combination, the present inventors exhibit surface tackiness during one-stage curing and temporary adhesion. It was found that it can be an excellent adhesive. Furthermore, they have found that such an adhesive enhances adhesion when two-stage curing is performed and exhibits excellent adhesive force, and has completed the present invention.

The adhesive of the present invention contains a thermoplastic resin.
By containing the thermoplastic resin, the temporary adhesion to the adherend can be sufficiently improved.

Examples of the thermoplastic resin include ethylene-α-olefin copolymers such as polyethylene, polypropylene, and ethylene-propylene copolymers, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, and ethylene-vinyl acetate copolymers. , Polyvinyl alcohol resin, polyvinyl acetal resin and the like. Examples thereof include fluoropolymers such as polyvinylidene fluoride and polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polystyrene, polyacrylonitrile, and styrene-acrylonitrile copolymers. Further, acrylonitrile-butadiene-styrene copolymer (ABS) resin, polyphenylene-ether copolymer (PPE) resin, modified PPE resin, aliphatic polyamides, aromatic polyamides, polyimide, polyamideimide and the like can be mentioned. Further, polymethacrylic acid esters such as polymethacrylic acid and polymethacrylic acid methyl ester, polyacrylic acids, polycarbonate, polyphenylene sulfide, silicone resin and the like can be mentioned. Of these, polyvinyl acetal resins and polymethacrylic acid esters are preferable, and polyvinyl acetal resins are more preferable.

In the polyvinyl acetal resin, the preferable lower limit of the average degree of polymerization is 100, and the preferable upper limit is 5000.
When the average degree of polymerization of the polyvinyl acetal resin is 100 or more, the mechanical strength of the obtained cured product can be sufficiently improved. When the average degree of polymerization of the polyvinyl acetal resin is 5000 or less, the solution viscosity can be made suitable for acetalization of polyvinyl alcohol.
The average degree of polymerization of the polyvinyl acetal resin has a more preferable lower limit of 600 and a more preferable upper limit of 4500.

The preferable lower limit of the acetal group amount of the polyvinyl acetal resin is 50 mol%, and the preferable upper limit is 85 mol%, regardless of whether the aldehyde is used alone or in combination of two or more kinds.
When the acetal group amount of the polyvinyl acetal resin is 50 mol% or more, the coatability of the adhesive can be improved. Moreover, the compatibility with the above-mentioned reactive diluent can be improved. When the acetal group content of the polyvinyl acetal resin is 85 mol% or less, the mechanical strength of the obtained cured product can be sufficiently improved.
Regarding the amount of acetal groups in the polyvinyl acetal resin, a more preferable lower limit is 54 mol%, a further preferable lower limit is 58 mol%, a particularly preferable lower limit is 60 mol%, a more preferable upper limit is 82 mol%, and a further preferable upper limit is 79 mol%. A particularly preferred upper limit is 77 mol%.
Regarding the calculation method of the amount of acetal groups, since the acetal group of the polyvinyl acetal resin is obtained by acetalizing the two hydroxyl groups of polyvinyl alcohol, a method of counting the two acetalized hydroxyl groups is used. adopt.
Further, in the present specification, when the acetal group is an acetal acetal group, it is also referred to as an acetal acetal group amount, and when the acetal group is a butyral group, it is also referred to as a butyral group amount.

Examples of the method for adjusting the acetal group amount of the polyvinyl acetal include a method for adjusting the addition amount of the aldehyde. If the amount of the aldehyde added is small, the amount of acetal groups in the polyvinyl acetal is low, and if the amount of the aldehyde added is large, the amount of acetal groups in the polyvinyl acetal is high.

The preferable lower limit of the amount of hydroxyl groups in the polyvinyl acetal resin is 16 mol%, and the preferable upper limit is 45 mol%.
When the amount of hydroxyl groups is 16 mol% or more, the mechanical strength of the obtained cured product can be sufficiently improved. In addition, the adhesive strength can be further improved. When the amount of hydroxyl groups is 45 mol% or less, moisture resistance and weather resistance can be improved. Further, it is possible to improve the temporary adhesion at the time of one-stage curing, and further to improve the adhesiveness at the time of two-stage curing.
Regarding the amount of hydroxyl groups of the polyvinyl acetal resin, a more preferable lower limit is 20 mol%, a more preferable lower limit is 22 mol%, a more preferable upper limit is 40 mol%, a further preferable upper limit is 38 mol%, and a further preferable upper limit is 36 mol%. A particularly preferred upper limit is 35 mol%.

The preferable lower limit of the amount of acetyl groups in the polyvinyl acetal resin is 0.1 mol%, and the preferable upper limit is 30 mol%.
When the amount of the acetyl group is 0.1 mol% or more, the mechanical strength of the obtained cured product can be sufficiently improved. In addition, the compatibility with the above-mentioned reactive diluent can be increased. When the amount of the acetyl group is 30 mol% or less, the temporary adhesion at the time of one-stage curing can be improved, and the adhesiveness at the time of two-stage curing can be improved. Moreover, the moisture resistance can be sufficiently improved.
As for the amount of acetyl groups, a more preferable lower limit is 0.2 mol%, a further preferable lower limit is 0.3 mol%, a more preferable upper limit is 24 mol%, a further preferable upper limit is 20 mol%, and a further preferable upper limit is 19.5. Mol%, a particularly preferred upper limit is 15 mol%.

As a method for adjusting the amount of acetyl group of the polyvinyl acetal within the above range, for example, a method for adjusting the degree of saponification of the polyvinyl alcohol can be mentioned. That is, the acetyl group amount of the polyvinyl acetal depends on the saponification degree of the polyvinyl alcohol, and if a polyvinyl alcohol having a low saponification degree is used, the acetyl group amount of the polyvinyl acetal becomes large and the saponification degree becomes high. If a high polyvinyl alcohol is used, the amount of acetyl group in the polyvinyl acetal becomes small.

The polyvinyl acetal resin is preferably a polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol having a saponification degree of 80 mol% or more. By using such a polyvinyl acetal resin, the stability of the adhesive can be improved and excellent mechanical strength can be exhibited over a long period of time.
If the degree of saponification of polyvinyl alcohol is less than 80 mol%, the solubility of polyvinyl alcohol in water decreases, which may make acetalization difficult. Further, since the amount of hydroxyl groups of polyvinyl alcohol is small, the acetalization reaction may be difficult to proceed.
A more preferable lower limit of the degree of saponification of the polyvinyl alcohol is 85 mol%.

The method for acetalization is not particularly limited, and conventionally known methods can be used. Examples thereof include a method of adding an aldehyde to an aqueous solution of polyvinyl alcohol in the presence of an acid catalyst such as hydrochloric acid.
The above aldehyde is not particularly limited, and examples thereof include formaldehyde (including paraformaldehyde), acetaldehyde (including paraacetaldehyde), propionaldehyde, butylaldehyde, amylaldehyde, hexylaldehyde, heptylaldehyde, 2-ethylhexylaldehyde, cyclohexylaldehyde and the like. Can be mentioned. Further, furfural, glioxal, glutaraldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, β-phenylpropionaldehyde and the like can be mentioned.

As the polyvinyl acetal resin, a polyvinyl butyral resin having an acetal group as a butyral group and a polyvinyl acetal acetal resin having an acetal group as an acetal acetal group are preferable, and the brightness deteriorates particularly when an adhesive is used for bonding prism sheets. Polyvinyl acetal acetal resin is more preferable because it can suppress the above.

In the adhesive of the present invention, the preferable lower limit of the content of the thermoplastic resin is 5% by weight, and the preferable upper limit is 40% by weight.
When the content of the thermoplastic resin is 5% by weight or more, the temporary adhesion at the time of one-stage curing can be improved. When the content of the thermoplastic resin is 40% by weight or less, the cohesive force can be improved during the two-stage curing to improve the adhesiveness.
The content of the thermoplastic resin has a more preferable lower limit of 10% by weight and a more preferable upper limit of 20% by weight.

The adhesive of the present invention contains a reactive diluent (A).
The reactive diluent (A) has a 90-degree peel-off adhesive strength of 5.5 N / 25 mm or more measured in accordance with JIS K 6851-1: 1999 when used for bonding PET to each other.
By containing the above-mentioned reactive diluent (A), it is possible to improve the tackability at the time of one-stage curing.
In the present specification, the reactive diluent can be compatible with the above-mentioned thermoplastic resin to liquefy the adhesive, and also reacts between the reactive diluents by irradiating with active energy rays. It means something that can be crosslinked and cured.

Examples of the reactive diluent (A) include a (meth) acrylic acid ester having a cyclic ether structure, a (meth) acrylic acid ester having two or more ester bonds, and a (meth) acrylic acid ester having a urethane bond. .. Further, an epoxy compound having an alkylene oxide structure, a polyfunctional alicyclic epoxy compound, a polyfunctional aliphatic epoxy compound, an aromatic epoxy compound and the like can be mentioned. These may be used alone or in combination. Among them, the reactive diluent (A) has two or more (meth) acrylic acid esters having a cyclic ether structure and two or more ester bonds because the temporary adhesiveness at the time of one-step curing can be further improved (). It is preferable to contain a (meth) acrylic acid ester such as a meta) acrylic acid ester. Further, in addition to the above (meth) acrylic acid ester, it is more preferable to further contain an epoxy compound such as an epoxy compound having an alkylene oxide structure, a polyfunctional alicyclic epoxy compound, and a polyfunctional aliphatic epoxy compound.

As the (meth) acrylic acid ester having a cyclic ether structure, it is preferable to use a (meth) acrylic acid ester having a cyclic ether structure in the range of a three-membered ring to a six-membered ring.
These may be monomeric esters or multimeric esters, and may be used alone or in combination of two or more.

Examples of the (meth) acrylic acid ester having a three-membered ring cyclic ether structure include glycidyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate glycidyl ether, and 3-hydroxypropyl (meth) acrylate glycidyl ether. Can be mentioned. In addition, 4-hydroxybutyl acrylate glycidyl ether, 5-hydroxypentyl (meth) acrylate glycidyl ether, 6-hydroxyhexyl (meth) acrylate glycidyl ether and the like can be mentioned.

Examples of the (meth) acrylic acid ester having a four-membered ring cyclic ether structure include (3-methyloxetane-3-yl) methyl (meth) acrylate and (3-propyloxetane-3-yl) methyl (meth). ) Acrylic, (3-ethyloxetane-3-yl) methyl (meth) acrylate and the like. In addition, (3-butyloxetane-3-yl) methyl (meth) acrylate, (3-ethyloxetane-3-yl) ethyl (meth) acrylate, (3-ethyloxetane-3-yl) propyl (meth) acrylate, Examples thereof include (3-ethyloxetane-3-yl) butyl (meth) acrylate. Further, (3-ethyloxetane-3-yl) pentyl (meth) acrylate, (3-ethyloxetane-3-yl) hexyl (meth) acrylate and the like can be mentioned.

Examples of the (meth) acrylic acid ester having a five-membered ring cyclic ether structure include tetrahydrofurfuryl (meth) acrylate, γ-butyrolactone (meth) acrylate, and (2,2-dimethyl-1,3-dioxolane-4-). Il) methyl (meth) acrylate and the like can be mentioned. In addition, (2-methyl-2-ethyl-1,3-dioxolan-4-yl) methyl (meth) acrylate, (2-methyl-2-isobutyl-1,3-dioxolan-4-yl) methyl (meth) Examples thereof include acrylate, (2-cyclohexyl-1,3-dioxolane-4-yl) methyl (meth) acrylate and the like. Furthermore, tetrahydrofurfuryl alcohol acrylic acid multimer ester can also be used.

Examples of the (meth) acrylic acid ester having a 6-membered ring cyclic ether structure include tetrahydro-2H-pyran-2-yl- (meth) acrylate and 2- {1-[(tetrahydro-2H-pyran-2). -Il) oxy] -2-methylpropyl} (meth) acrylate and the like. Further, cyclic trimethylolpropane formal acrylate, (meth) acryloyl morpholine and the like can be mentioned.

The (meth) acrylic acid ester having a cyclic ether structure has a five-membered ring or more from the viewpoint that the adhesion is further improved by dissolving the polycarbonate surface, especially when a polycarbonate base material is used as the plastic base material. Is preferably used. Among them, tetrahydrofurfuryl (meth) acrylate, tetrahydrofurfuryl alcohol acrylic acid multimer ester, (2-methyl-2-ethyl-) are particularly excellent in solubility and can further improve adhesion to a polycarbonate substrate. 1,3-Dioxolane-4-yl) methyl (meth) acrylate is more preferred.

The (meth) acrylic acid ester having two or more ester bonds is, for example, derived from a polyfunctional (meth) acrylic acid ester having two or more ester bonds derived from (meth) acrylic acid, or (meth) acrylic acid. Examples thereof include (meth) acrylic acid esters having an ester bond other than the ester bond. Specifically, a lactone-modified (meth) acrylate compound obtained by reacting a (meth) acrylic acid ester with a lactone compound, and a polyester (meth) acrylate compound obtained by reacting a polyester polyol with (meth) acrylic acid. And so on.

In the lactone-modified (meth) acrylate compound obtained by reacting the (meth) acrylic acid ester with the lactone compound, the (meth) acrylic acid ester includes an aliphatic (meth) acrylate compound and an aromatic (meth) acrylate. Examples include compounds.
Examples of the aliphatic (meth) acrylate compound include 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, glycerin diacrylate, trimethylolpropane diacrylate, pentaerythritol triacrylate, and dipentaerythritol penta. Examples include acrylate.
Examples of the aromatic (meth) acrylate compound include 4-hydroxyphenyl acrylate, β-hydroxyphenethyl acrylate, 4-hydroxyphenethyl acrylate, 1-phenyl-2-hydroxyethyl acrylate, and 3-hydroxy acrylate. Examples thereof include -4-acetylphenyl and 2-hydroxy-3-phenoxypropyl acrylate. Examples of the lactone compound include ε-caprolactone and γ-butyrolactone.

In the polyester (meth) acrylate compound obtained by reacting the polyester polyol with (meth) acrylic acid, the polyester polyol is composed of a polybasic acid and a polyhydric alcohol.

Examples of the polybasic acid include aliphatic dibasic acid, alicyclic dibasic acid, aromatic dibasic acid, aliphatic tribasic acid, aromatic tribasic acid, and an anhydride thereof.
Examples of the aliphatic dibasic acid include malonic acid, succinic acid, glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, and tetradecanedioic acid. , Pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecandioic acid, icosandioic acid and the like. Further, tetrahydrophthalic acid, maleic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid and the like can be mentioned. Examples of the alicyclic dibasic acid include hexahydrophthalic acid and 1,4-cyclohexanedicarboxylic acid. Examples of the aromatic dibasic acid include phthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid and the like. Examples of the aliphatic tribasic acid include 1,2,5-hexanetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid and the like. Examples of the aromatic tribasic acid include trimellitic acid, trimellitic anhydride, 1,2,5-benzenetricarboxylic acid, 2,5,7-naphthalene tricarboxylic acid and the like.

Further, examples of the polyhydric alcohol include a divalent polyhydric alcohol and a trihydric or higher polyhydric alcohol.
Examples of the divalent polyhydric alcohol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2,2-trimethyl-1,3-propanediol, and 2,2-dimethyl-3-isopropyl-. Examples thereof include 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol and the like. In addition, 1,5-pentanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 2,2,4-trimethyl-1,3 -Pentanediol and the like can be mentioned. Examples of the above-mentioned trihydric or higher polyhydric alcohol include trimethylolethane, trimethylolpropane, glycerin, hexanetriol, pentaerythritol and the like. Further, as the polyhydric alcohol, a modified polyether polyol obtained by ring-opening polymerization of the divalent polyhydric alcohol or the trihydric or higher polyhydric alcohol and the cyclic ether bond-containing compound may be used. Examples of the cyclic ether bond-containing compound include ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether, and allyl glycidyl ether. Further, a lactone-modified polyester polyol obtained by a polycondensation reaction between the divalent polyhydric alcohol or the trihydric or higher polyhydric alcohol and the lactone compound may be used.

By using the (meth) acrylic acid ester having two or more of the above ester bonds, the adhesion to the plastic can be improved.
The lower limit of the acid value of the (meth) acrylic acid ester having two or more ester bonds is preferably 20 mgKOH / g.
When the acid value is 20 mgKOH / g or more, the adhesion can be further improved.
A more preferable lower limit of the acid value is 100 mgKOH / g.
The upper limit of the acid value is not particularly limited, but a preferable upper limit is 500 mgKOH / g, and a more preferable upper limit is 300 mgKOH / g.

Examples of the (meth) acrylic acid ester having a urethane bond include those obtained by reacting an isocyanate compound with a (meth) acrylic acid derivative having a hydroxyl group.

Examples of the isocyanate compound used as a raw material for the (meth) acrylic acid ester having a urethane bond include isophorone diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate. Can be mentioned. In addition, diphenylmethane-4,4'-diisocyanate (MDI), hydrogenated MDI, polypeptide MDI, 1,5-naphthalenediocyanate, norbornan diisocyanate, trizine diisocyanate, xylylene diisocyanate (XDI), hydrogenated XDI, lysine diisocyanate, triphenyl. Examples thereof include methane triisocyanate. Further, tris (isocyanatephenyl) thiophosphate, tetramethylxylylene diisocyanate, 1,6,11-undecanetriisocyanate and the like can be mentioned.

Examples of the isocyanate compound include a chain-extended isocyanate compound obtained by reacting a polyol such as ethylene glycol, propylene glycol, glycerin, sorbitol, polyether diol, polyester diol, and polycaprolactone diol with an excess of isocyanate compound. Can also be used.

Examples of the (meth) acrylic acid derivative having a hydroxyl group, which is a raw material of the (meth) acrylic acid ester having a urethane bond, include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, and 1, , 4-Butanediol, mono (meth) acrylate of dihydric alcohol such as polyethylene glycol and the like can be mentioned. Further, mono (meth) acrylates or di (meth) acrylates of trivalent alcohols such as trimethylolethane, trimethylolpropane and glycerin, and epoxy (meth) acrylates such as bisphenol A type epoxy (meth) acrylate can be mentioned.

Examples of the alkylene oxide group contained in the epoxy compound having an alkylene oxide structure include an oxymethylene group, an oxyethylene group, an oxypropylene group and an oxybutylene group.
The number of moles added to the alkylene oxide structure is preferably 1 to 10.
Examples of the epoxy compound having an alkylene oxide structure include an alkylene oxide adduct of a bisphenol F type epoxy resin, an alkylene oxide adduct of a bisphenol A type epoxy resin, a glycidyl ether adduct of polyethylene glycol, and a glycidyl ether adduct of polypropylene glycol. Can be mentioned.

Examples of the polyfunctional alicyclic epoxy compound include a cyclopentadiene type epoxy compound and a dicyclopentadiene type epoxy compound such as dicyclopentadiene dimethanol diglycidyl ether.

Examples of the polyfunctional aliphatic epoxy compound include trimethylolpropane diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and propylene glycol diglycidyl ether. Can be mentioned. In addition, neopentyl glycol diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, polyglycerol triglycidyl ether, diglycerol triglycidyl ether and the like can be mentioned.

The reactive diluent (A) has a (meth) acrylic acid ester having two or more ester bonds, a (meth) acrylic acid ester having a cyclic ether structure, a polyfunctional alicyclic epoxy compound, and an alkylene oxide structure. Epoxy compounds are more preferably used. Among them, a lactone-modified (meth) acrylate compound, a (meth) acrylic acid ester having a cyclic ether structure of five-membered ring or more, a dicyclopentadiene type epoxy compound, and an alkylene oxide adduct of a bisphenol A type epoxy resin are particularly preferably used. ..

The content of the (meth) acrylic acid ester having two or more of the above ester bonds in the reactive diluent (A) has a preferable lower limit of 30% by weight, a more preferable lower limit of 50% by weight, and a preferable upper limit of 85% by weight. A more preferable upper limit is 70% by weight.

The content of the (meth) acrylic acid ester having the cyclic ether structure in the reactive diluent (A) has a preferable lower limit of 5% by weight, a more preferable lower limit of 15% by weight, and a preferable upper limit of 85% by weight, more preferably. The upper limit is 50% by weight.

The content of the epoxy compound in the reactive diluent (A) is such that the preferable lower limit is 5% by weight, the more preferable lower limit is 10% by weight, the preferable upper limit is 30% by weight, and the more preferable upper limit is 25% by weight.

In the adhesive of the present invention, the preferable lower limit of the content of the reactive diluent (A) is 30% by weight, and the preferable upper limit is 85% by weight.
When the content of the reactive diluent (A) is 30% by weight or more, the temporary adhesion at the time of one-stage curing can be improved. When the content of the reactive diluent (A) is 85% by weight or less, the adhesion is enhanced during the two-stage curing and the adhesiveness can be improved.
The content of the reactive diluent (A) has a more preferable lower limit of 50% by weight and a more preferable upper limit of 70% by weight.

In the adhesive of the present invention, the content of the (meth) acrylic acid ester having two or more of the above ester bonds is preferably 0% by weight, a more preferable lower limit is 10% by weight, and a further preferable lower limit is 30% by weight. The upper limit is 85% by weight, the more preferable upper limit is 75% by weight, and the more preferable upper limit is 65% by weight.

In the adhesive of the present invention, the content of the (meth) acrylic acid ester having the cyclic ether structure has a preferable lower limit of 0% by weight, a more preferable lower limit of 5% by weight, a further preferable lower limit of 15% by weight, and a preferable upper limit. 85% by weight, a more preferred upper limit is 65% by weight, and a more preferred upper limit is 50% by weight.

In the adhesive of the present invention, the preferable lower limit of the content of the epoxy compound is 0% by weight, the more preferable lower limit is 5% by weight, the more preferable lower limit is 10% by weight, the preferable upper limit is 35% by weight, and the more preferable upper limit is 30. By weight%, a more preferred upper limit is 25% by weight.

In the adhesive of the present invention, the ratio of the content (mol) of the thermoplastic resin to the content (mol) of the diluent (A) (content of the thermoplastic resin / content of the diluent (A)). The preferred lower limit is 0.0003, the more preferred lower limit is 0.0009, the preferred upper limit is 0.004, and the more preferred upper limit is 0.002.
The content (mol) of the thermoplastic resin and the diluent (A) can be calculated based on the molecular weight and the amount of the diluent (A) added. When the thermoplastic resin is a polyvinyl acetal resin, the molecular weight of the polyvinyl acetal resin can be calculated based on the average degree of polymerization, the acetal group amount, the hydroxyl group amount, the acetyl group amount and the molecular weight of each structural unit. ..

In the adhesive of the present invention, the ratio of the total number of acetal groups to the total number of functional groups ((meth) acrylic group or epoxy group) of the diluent (A) (number of acetal groups / number of functional groups of the diluent (A)) is preferable. The lower limit is 0.13, the more preferred lower limit is 0.18, the preferred upper limit is 0.70, and the more preferred upper limit is 0.40.
The total number of acetal groups can be calculated based on the molecular weight, average degree of polymerization, acetal group amount of the polyvinyl acetal resin and the addition amount of the polyvinyl acetal resin in the adhesive of the present invention.
The total number of functional groups of the diluent (A) is the molecular weight of the diluent (A), the number of functional groups in one molecule of the diluent (A), and the diluent (A) in the adhesive of the present invention. ) Can be calculated based on the addition amount.

In the adhesive of the present invention, the ratio of the molecular weight of the thermoplastic resin to the functional group equivalent of the diluent (A) (molecular weight per (meth) acrylic group or epoxy group) (molecular weight / dilution of the thermoplastic resin). The functional group equivalent of the agent (A)) has a preferable lower limit of 80, a more preferable lower limit of 180, a preferable upper limit of 300, and a more preferable upper limit of 250.
The functional group equivalent of the diluent (A) can be calculated based on the molecular weight of the diluent (A) and the number of functional groups in one molecule of the diluent (A).
When the diluent (A) contains a plurality of diluents, the functional group equivalent of the diluent (A) is the amount of the diluent (A) added to the adhesive of the present invention and the diluent (A). ) Can be calculated based on the total number of functional groups.

The adhesive of the present invention preferably contains a reactive diluent (B) other than the reactive diluent (A) in addition to the reactive diluent (A).
That is, the reactive diluent (B) has a 90-degree peel-off adhesive strength of less than 5.5 N / 25 mm measured in accordance with JIS K 6851-1: 1999 when used for adhesion between PETs.
By containing the above-mentioned reactive diluent (B), the adhesiveness at the time of two-stage curing can be further improved.

Examples of the reactive diluent (B) include (meth) acrylic acid esters and epoxy compounds other than the reactive diluent (A). For example, a (meth) acrylic acid ester having an alkylene oxide structure having 1 to 3 carbon atoms, a (meth) acrylic acid alkyl ester, a (meth) acrylic acid ester having a polar group, an acryloyl group-containing polyvalent carboxylic acid ester, and an aromatic. Examples include epoxy compounds.

Examples of the alkylene oxide group contained in the (meth) acrylic acid ester having an alkylene oxide structure having 1 to 3 carbon atoms include an oxymethylene group and an oxyethylene group.
The number of moles added to the alkylene oxide structure is preferably 1 to 10.
Examples of the (meth) acrylic acid ester having an alkylene oxide structure include methoxypolyethylene glycol (meth) acrylate and ethoxypolyethylene glycol (meth) acrylate.

Examples of the (meth) acrylic acid alkyl ester include (meth) acrylic acid esters having an alkyl group having 1 to 20 carbon atoms. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth). ) Acrylate and the like can be mentioned. In addition, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, lauryl ( Meta) acrylate and the like can be mentioned.

Examples of the (meth) acrylic acid ester having the above polar group include (meth) acrylic acid ester having a hydroxyl group, an amide group, an amino group, an isocyanate group and the like as the polar group.
Examples of the (meth) acrylic acid ester having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and polyethylene glycol (meth) acrylic acid ester. , Glyxyl (meth) acrylate and the like.
Examples of the (meth) acrylic acid ester having an amide group include N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, (meth) acryloyl morpholine, and N-isopropyl (meth) acrylamide. , N-Hydroxyethyl (meth) acrylamide and the like.
Examples of the (meth) acrylic acid ester having an amino group include N-dialkylaminoalkyl (meth) acrylamide, N, N-dialkylaminoalkyl (meth) acrylamide and the like. Specifically, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-di-t-butylamino. Ethyl (meth) acrylate, N, N-dimethylaminobutyl (meth) acrylate and the like can be mentioned. Further, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide and the like can be mentioned.
Examples of the (meth) acrylic acid ester having an isocyanate group include 2-isocyanatoethyl (meth) acrylate.
Examples of the acryloyl group-containing multivalent carboxylic acid ester include 2-acryloyloxyethyl succinate and the like.

Examples of the aromatic epoxy compound include bisphenol A type glycidyl ether epoxy resin, bisphenol F type glycidyl ether epoxy resin, and phenol novolac type glycidyl ether epoxy resin.

As the reactive diluent (B), methoxypolyethylene glycol (meth) acrylate, (meth) acrylic acid ester having an amide group, acryloyl group-containing polyvalent carboxylic acid ester, and aromatic epoxy compound are preferably used. Further, it is preferable to use a combination of a (meth) acrylic acid ester having an alkylene oxide structure having 1 to 3 carbon atoms, a (meth) acrylic acid alkyl ester, and a (meth) acrylic acid ester having a polar group.

In the adhesive of the present invention, the content of the reactive diluent (B) is such that the preferable lower limit is 10% by weight, the more preferable lower limit is 20% by weight, the preferable upper limit is 40% by weight, and the more preferable upper limit is 30% by weight. is there.

In the adhesive of the present invention, the content of the (meth) acrylic acid ester having an alkylene oxide structure having 1 to 3 carbon atoms has a preferable lower limit of 5% by weight, a more preferable lower limit of 10% by weight, and a preferable upper limit of 25% by weight. %, The more preferable upper limit is 20% by weight.

In the adhesive of the present invention, the content of the (meth) acrylic acid alkyl ester has a preferable lower limit of 5% by weight, a more preferable lower limit of 10% by weight, a preferable upper limit of 20% by weight, and a more preferable upper limit of 15% by weight. is there.

In the adhesive of the present invention, the content of the (meth) acrylic acid ester having the polar group has a preferable lower limit of 2% by weight, a more preferable lower limit of 4% by weight, a preferable upper limit of 10% by weight, and a more preferable upper limit of 7. By weight%.

In the adhesive of the present invention, the content of the reactive diluent (B) with respect to 100 parts by weight of the reactive diluent (A) has a preferable lower limit of 0 parts by weight, a more preferable lower limit of 10 parts by weight, and a preferable upper limit. 50 parts by weight, more preferably 30 parts by weight.

In the adhesive of the present invention, the ratio of the content (mol) of the thermoplastic resin to the total content (mol) of the diluents (A) and (B) (thermoplastic resin content / diluent (A). ) And (B), the preferable lower limit is 0.0002, the more preferable lower limit is 0.00075, the preferable upper limit is 0.3, and the more preferable upper limit is 0.0015.

In the adhesive of the present invention, the ratio of the total number of acetal groups to the total number of functional groups ((meth) acrylic groups or epoxy groups) of the diluents (A) and (B) (number of acetal groups / diluent (A) and (B). ), The preferable lower limit is 0.05, the more preferable lower limit is 0.13, the preferable upper limit is 0.6, and the more preferable upper limit is 0.2.

The ratio of the total number of epoxy groups to the total number of (meth) acrylic groups in the adhesive of the present invention (number of epoxy groups / number of (meth) acrylic groups) has a preferable lower limit of 0.05, a more preferable lower limit of 0.2, and a preferable upper limit. Is 0.5, and a more preferable upper limit is 0.3.

In the adhesive of the present invention, the ratio (thermoplastic resin) of the molecular weight of the thermoplastic resin to the functional group equivalents (molecular weight per (meth) acrylic group or epoxy group) of the diluents (A) and (B). The molecular weight / functional group equivalent of the diluents (A) and (B)) has a preferable lower limit of 110, a more preferable lower limit of 140, a preferable upper limit of 300, and a more preferable upper limit of 190.
The functional group equivalents of the diluents (A) and (B) are the amount of the diluents (A) and (B) added to the adhesive of the present invention and the functional groups of the diluents (A) and (B). It can be calculated based on the total number of groups.

The adhesive of the present invention contains a photoreaction initiator.
Specific examples of the photoreaction initiator include an acylphosphine oxide-based photoreaction initiator, a titanosen-based photoreaction initiator, an acetophenone-based photoreaction initiator, a benzoin-based photoreaction initiator, and a benzophenone-based photoreaction initiator. Examples thereof include a thioxanthone-based photoreaction initiator and a sulfonium salt-based photoreaction initiator.
Examples of the acylphosphine oxide-based photoreaction initiator include 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and bis (2,6-dimethoxy). Benzoyl) -2,4,4-trimethylpentylphosphine oxide and the like can be mentioned.
Examples of the titanosen-based photoreaction initiator include bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl). Titanium and the like can be mentioned.
Examples of the acetophenone-based photoreaction initiator include 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2-methyl. -1- (4-Methylthiophenyl) -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, 1,2- (dimethylamino) -2-[ (4-Methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-hydroxy Examples thereof include -2-methyl-1- [4- (1-methylvinyl) phenyl] propanone oligomer.
Examples of the benzoin-based photoreaction initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and the like.
Examples of the benzophenone-based photoreaction initiator include benzophenone, methyl o-benzoyl benzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenylsulfide, 3,3', 4,4'-tetra ( t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethaminium bromide , (4-Benzoylbenzyl) trimethylammonium chloride and the like.
Examples of the thioxanthone-based photoreaction initiator include 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, and 2- (3- (3-). Dimethylamino-2-hydroxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride and the like can be mentioned.
Examples of the sulfonium salt-based photoreaction initiator include tris (4- (4-acetylphenyl) thiophenyl) sulfonium tetrakis (pentafluorophenyl) borate and the like.
These photoreaction initiators may be used alone or in combination of two or more.

In addition, as these auxiliaries, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michler ketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethyl benzoate, 4-dimethylaminobenzoate Ethyl can be mentioned. In addition, 4-dimethylaminobenzoic acid (n-butoxy) ethyl, 4-dimethylaminobenzoate isoamyl, 4-dimethylaminobenzoate 2-ethylhexyl, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone. Etc. can be used together.

Among them, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenyl ketone, benzoyl isopropyl ether, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 2-hydroxy- It is preferable to use 2-methyl-1-phenylpropan-1-one, tris (4- (4-acetylphenyl) thiophenyl) sulfonium tetrakis (pentafluorophenyl) borate.

In the adhesive of the present invention, the preferable lower limit of the content of the photoreaction initiator is 0.01% by weight, and the preferable upper limit is 10% by weight. When the content of the photoreaction initiator is in this range, the obtained adhesive is more excellent in photocurability and storage stability. The more preferable lower limit of the content of the photoreaction initiator is 0.1% by weight, and the more preferable upper limit is 5% by weight.

In addition, the adhesive of the present invention may further contain a non-reactive component.
In the present specification, the non-reactive component can be compatible with the above-mentioned thermoplastic resin and does not contain a reactive double bond in the compound or has a reactive double bond. Also means a compound that does not substantially exhibit polymerization reactivity.
Specific examples of the non-reactive component include plasticizers such as organic acid esters, organic phosphoric acid esters, and organic phosphite esters, tackifiers such as rosin-based resins and terpene-based resins, and solvent-free acrylics. Examples include polymers. Examples of the plasticizer include organic acid ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, and phosphoric acid plasticizers such as organic phosphoric acid plasticizers and organic phosphite plasticizers. .. Of these, organic acid ester plasticizers are preferable. These plasticizers may be used alone or in combination of two or more. The plasticizer is preferably a liquid plasticizer.

Examples of the organic acid ester include monobasic organic acid ester and polybasic organic acid ester.
The monobasic organic acid ester is not particularly limited. For example, monobasic organic acids such as butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptyl acid, n-octyl acid, 2-ethylhexic acid, pelargonic acid (n-nonyl acid), decyl acid, and triethylene. Examples thereof include glycol esters obtained by reacting with glycols such as glycols, tetraethylene glycols and tripropylene glycols.
The above-mentioned multibasic organic acid ester is not particularly limited, and is, for example, by reaction of a multibasic organic acid such as adipic acid, sebacic acid, and azelaic acid with an alcohol having a linear or branched structure having 4 to 8 carbon atoms. Examples thereof include the obtained ester compounds.

Specific examples of the organic acid ester include triethylene glycol-di-2-ethylbutyrate (3GH), triethylene glycol-di-2-ethylhexanoate (3GO), and triethylene glycol dicaprelate. Examples thereof include triethylene glycol di-n-octanoate and triethylene glycol-di-n-heptanoate (3G7). In addition, tetraethylene glycol-di-n-heptanoate (4G7), tetraethylene glycol-di-2-ethylhexanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethyl butyrate. , 1,3-Propylene glycol di-2-ethylbutyrate and the like. Further, 1,4-butylene glycol di-2-ethylbutyrate, diethylene glycol-di-2-ethylbutyrate, diethylene glycol-di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate and the like can be mentioned. Be done. In addition, triethylene glycol di-2-ethylpentanoate, tetraethylene glycol-di-2-ethylbutyrate (4GH), diethylene glycol dicapriate, dihexyl adipate (DHA), dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, Heptyl nonyl adipate and the like can be mentioned. Other examples include oil-modified sebacic acid alkyd, a mixture of a phosphoric acid ester and an adipate ester, and a mixed adipate ester prepared from an alkyl alcohol having 4 to 9 carbon atoms and a cyclic alcohol having 4 to 9 carbon atoms. Of these, DHA, 3GO, 4GO, 3GH, 4GH, and 3G7 are preferable. Further, 3GH, 3G7 and 3GO are more preferable, and 3GO is further preferable.

Examples of the organic phosphoric acid ester or organic phosphite ester include compounds obtained by a condensation reaction between phosphoric acid or phosphorous acid and an alcohol. Of these, a compound obtained by a condensation reaction between an alcohol having 1 to 12 carbon atoms and phosphoric acid or phosphorous acid is preferable. Examples of the alcohol having 1 to 12 carbon atoms include methanol, ethanol, butanol, hexanol, 2-ethylbutanol, heptanol, octanol, 2-ethylhexanol, decanol, dodecanol, butoxyethanol, butoxyethoxyethanol, benzyl alcohol and the like. Can be mentioned.
Examples of the organic phosphate ester or organic phosphate ester include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tri (2-ethylhexyl) phosphate, and tri (butoxyethyl) phosphate. Examples thereof include tri (2-ethylhexyl) phosphite, isodecylphenyl phosphate, and triisopropyl phosphate.

Examples of the rosin-based resin include rosin diol and the like.
The rosin diol is not particularly limited as long as it is a rosin-modified diol having two rosin skeletons and two hydroxyl groups in the molecule. A diol having a rosin component in the molecule is called a rosin polyol, which includes a polyether type having a skeleton excluding the rosin component such as polypropylene glycol (PPG), a condensation polyester polyol, and a lactone polyester polyol. There is a polyester type such as polycarbonate diol.
The rosin diol has a hydroxyl group such as a rosin ester obtained by reacting rosin with a polyhydric alcohol, an epoxy-modified rosin ester obtained by reacting rosin with an epoxy compound, and a polyether having a rosin skeleton. Examples include modified rosin. These can be produced by conventionally known methods.

Examples of the rosin component include pimaric acid-type resin acids such as abietic acid and its derivatives dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, diavietic acid, neoavietic acid, and levopimaric acid, and hydrogenated water thereof. Examples thereof include supplementary rosin and disproportionated rosin obtained by disproportionating these.
Examples of commercially available rosin-based resins include Pine Crystal D-6011, KE-615-3, KR-614, KE-100, KE-311, KE-359, and KE-604 manufactured by Arakawa Chemical Industries, Ltd. D-6250 and the like can be mentioned.

Examples of the terpene-based resin include terpene phenol-based resins and the like.
The terpene phenol-based resin is a copolymer of a terpene-based resin, which is an essential oil component obtained from a natural product such as pine tar or orange peel, and phenol, and at least a part of the copolymer is hydrogenated. Partially hydrogenated terpene phenolic resins or fully hydrogenated fully hydrogenated terpene phenolic resins are also included.
Here, the completely hydrogenated terpene phenol-based resin is a terpene-based resin (adhesive-imparting resin) obtained by substantially completely hydrolyzing the terpene phenol-based resin, and the partially hydrogenated terpene phenol-based resin is It is a terpene resin (adhesive-imparting resin) obtained by partially watering a terpene phenol resin. The terpene phenolic resin has a terpene-derived double bond and a phenol-derived aromatic ring double bond. Therefore, the fully hydrogenated terpene phenolic resin means a tackifier resin in which both the terpene moiety and the phenol moiety are completely or almost hydrolyzed, and the partially hydrogenated terpene phenolic resin means them. It means a terpene phenolic resin in which the degree of watering of the part is not perfect and is partial. The hydrogenation method and reaction form are not particularly limited.
Examples of commercially available products of the terpene phenol-based resin include YS Polystar NH (fully hydrogenated terpene phenol-based resin) manufactured by Yasuhara Chemical Co., Ltd.

Examples of the solvent-free acrylic polymer include a polymer of at least one monomer selected from (meth) acrylic acid alkyl esters having an alkyl group having 1 to 20 carbon atoms, or the monomer and others. Examples thereof include a copolymer with a copolymerizable monomer of.
Examples of commercially available products of the solvent-free acrylic polymer include ARUFON-UP1000 series, UH2000 series, and UC3000 series manufactured by Toagosei Co., Ltd.

In addition, the adhesive of the present invention may contain various additives as other optional components as long as the purpose and effect of the present invention are not impaired.
Examples of the additives include adhesive strength modifiers, tackifier resins, plasticizers, emulsifiers, softeners, fine particles, fillers, pigments, dyes, silane coupling agents, antioxidants, surfactants, waxes and the like. ..

The adhesive of the present invention is preferably an elastic modulus in a dynamic viscoelasticity measurement of dose 3000 mJ / cm ² of the active energy ray cured product obtained by curing by irradiating is 1 × 10 5 ^Pa or more.
When the elastic modulus of the cured product is at 1 × 10 5 ^Pa or more, the prism can ground without the buried, it is possible to improve the brightness.
The more preferable lower limit of the elastic modulus is 5 × 10 ⁵ Pa, the preferable upper limit is 5 × 10 ⁷ Pa, and the more preferable upper limit is 5 × 10 ⁶ Pa.
The elastic modulus can be measured by using, for example, a dynamic viscoelasticity measuring device.
The elastic modulus means the elastic modulus at 50 ° C.

The adhesive of the present invention preferably has a tan δ peak temperature of 50 ° C. or higher derived from the thermoplastic resin of the cured product obtained by irradiating and curing an active energy ray having an irradiation amount of 3000 mJ / cm ^2.
When the tan δ peak temperature is 50 ° C. or higher, the brightness can be maintained even when pressure is applied.
The more preferable lower limit of the tan δ peak temperature is 60 ° C, the preferable upper limit is 80 ° C, and the more preferable upper limit is 70 ° C.
The tan δ peak temperature can be measured by using, for example, a dynamic viscoelasticity measuring device.

The adhesive of the present invention is prepared by mixing a thermoplastic resin, a reactive diluent (A), a photoreactive initiator, a reactive diluent (B) added as needed, a stabilizer, and the like. Can be made.

The adhesive of the present invention can be used as an adhesive between the same or different materials such as fibers, composite materials, ceramics, glass, rubber, concrete, paper, metals and plastics.
Specifically, it manufactures building materials such as wallpaper, laminated plywood, and security glass, manufactures window glass with UV cut filters for automobiles, adheres labels to beverage bottles, cans, bottles, etc., and attaches labels to show windows, etc. It can be used for adhering exhibits and the like, adhering optical disk substrates, adhering non-contact IC cards, adhering IC chips, adhering cover glass for organic EL lighting, and the like. Further, it can be used for bonding display members such as projection televisions and organic EL displays having a completely solid sealing structure, bonding between a touch panel and a liquid crystal panel, and bonding between a touch panel and a front window, or a touch panel inside a touch panel. .. Further, it can be suitably used for bonding various materials and members such as bonding of various optical films used for flat panel displays and bonding of laminated plates used for electric circuits, and for manufacturing laminated bodies. Examples of the optical film include a brightness improving film, a prism sheet, a light diffusing sheet, a Frenel lens, a lenticular lens, a polarizing film, a retardation film, a color filter, a light guide plate, an antiglare film, an antireflection film, a reflection sheet, and near. Examples thereof include an infrared cut filter, a viewing angle control film, and a viewing angle compensation film.
The adhesive of the present invention can be preferably used for adhering plastics, has excellent temporary adhesion during one-step curing, and further enhances adhesion by two-step curing to exhibit excellent adhesiveness. It can be particularly preferably used for bonding an optical film such as a prism sheet that requires bonding in an area.

The method of adhering the adherend using the adhesive of the present invention is not particularly limited. For example, after the step of applying the adhesive of the present invention to the first member, the step of laminating and crimping the first member and the second member (bonding step), and the laminating step, the active energy It is preferable to perform a step of irradiating a wire and temporarily adhering (one-step curing step), and a step of further irradiating an active energy ray and adhering after the above-mentioned one-step curing step (two-step curing step).

When applying the above adhesive to the adherend, for example, a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater, etc. may be used, or a dipping method may be used. It is possible to perform coating by.

For the bonding and crimping, for example, a roll laminator or the like can be used, and the pressure thereof is selected from the range of 0.1 to 10 MPa.
For the above active energy ray irradiation, in addition to far ultraviolet rays, ultraviolet rays, near ultraviolet rays, rays such as infrared rays, electromagnetic waves such as X-rays and γ-rays, electron beams, proton rays, neutron rays and the like can be used. Curing by ultraviolet irradiation is advantageous because of the availability of the device and the price.

As the light source for irradiating the ultraviolet rays, a high-pressure mercury lamp, an electrodeless lamp, an ultra-high pressure mercury lamp carbon arc lamp, a xenon lamp, a metal halide lamp, a chemical lamp, a black light, an LED and the like are used.
The integrated exposure amount when irradiating with ultraviolet rays is preferably ^{2 to} 3000 mJ / cm 2, more preferably 10 to 2000 mJ / cm ² .

Especially in the case of the high-pressure mercury lamp, for example, preferably 5~3000mJ / cm ^2, more preferably at a condition of 50~2000mJ / cm ^2.
Further, in the case of the electrodeless lamp, for example, the condition ^{is preferably 2 to} 2000 mJ / cm 2, more preferably 10 to 1000 mJ / cm ^2.

The irradiation time varies depending on the type of light source, the distance between the light source and the coated surface, the coating thickness, and other conditions, but is usually several seconds to several tens of seconds, and in some cases, a fraction of a second. On the other hand, in the case of the above-mentioned electron beam irradiation, for example, it is preferable to use an electron beam having an energy in the range of 50 to 1000 keV, and an irradiation amount of 2 to 50 mad is preferable.

According to the present invention, it is possible to exhibit surface tackiness to improve temporary adhesion, and further, it is possible to exhibit excellent adhesive force by enhancing adhesion even after temporary attachment, and it is excellent in transparency. In particular, it is possible to provide an adhesive capable of suppressing deterioration of brightness when used for bonding optical films.

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

(Examples 1 to 4, 6 to 9, 12 and 13)
240 g of polyvinyl alcohol (polymerization degree 650, saponification degree 99 mol%) was added to 1800 g of pure water, and the mixture was dissolved by stirring at 90 ° C. for 2 hours. This solution was cooled to 40 ° C., 170 g of hydrochloric acid having a concentration of 35% by weight and 275 g of n-butyraldehyde were added, and the liquid temperature was maintained at 40 ° C. to carry out an acetalization reaction to precipitate a reaction product.
Then, the liquid temperature was maintained at 40 ° C. for 3 hours to complete the reaction, and the mixture was neutralized, washed with water and dried by a conventional method to obtain a polyvinyl butyral resin powder.
The obtained polyvinyl butyral resin was dissolved in _{DMSO-D 6} ^{(dimethyl sulfoxide) and measured using 13} C-NMR (nuclear magnetic resonance spectrum). As a result, the amount of hydroxyl groups was 34 mol% and the amount of butyral groups was 65 mol%. , The amount of acetyl group was 1 mol%.

The obtained polyvinyl butyral resin was used as the thermoplastic resin, and as shown in Table 1, the thermoplastic resin, the reactive diluent (A), the reactive diluent (B) and the photoreaction initiator were added. An adhesive was prepared.

The following agents were used as the reactive diluent (A), the reactive diluent (B), and the photoreaction initiator. Further, regarding the reactive diluent (A) and the reactive diluent (B), in accordance with JIS K 6854-1: 1999, the peeling angle when the PET films are bonded to each other is 90 degrees, and the peeling speed is 300 mm / min. The peel-off adhesive strength was measured under the conditions of.
<Reactive diluent (A)>
[(Meta) acrylate]
M-5300: ω-carboxy-polycaprolactone (n≈2) monoacrylate, manufactured by Toagosei Co., Ltd., molecular weight 300.3, 90 degree peeling adhesive strength 6.2N / 25mm, acid value 230mgKOH / g
Viscoat # 150D: Tetrahydrofurfuryl alcohol acrylic acid multimer ester, manufactured by Osaka Organic Chemical Industry Co., Ltd., molecular weight 156.2, 90 degree peeling adhesive strength 8.5N / 25mm
MEDOL-10: (2-methyl-2-ethyl-1,3-dioxolane-4-yl) methyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., molecular weight 208.3, 90 degree peeling adhesive strength 10.5 N / 25 mm
[Epoxy compound]
EP-4088: Dicyclopentadiene dimethanol diglycidyl ether, manufactured by ADEKA, molecular weight 340, 90 degree peeling adhesive strength 6.4 N / 25 mm
EP-4003S: Propylene oxide adduct of bisphenol A type epoxy resin, manufactured by ADEKA, molecular weight 940, 90 degree peeling adhesive strength 7.3N / 25mm
<Reactive diluent (B)>
[(Meta) acrylate]
M-90G: Methoxypolyethylene glycol # 400 methacrylate, manufactured by Shin Nakamura Chemical Industry Co., Ltd., molecular weight 468, 90 degree peeling adhesive strength 2.5N / 25mm
DMAA: N, N-dimethylacrylamide, manufactured by KJ Chemicals, molecular weight 99.1, 90 degree peeling adhesive strength 0.17N / 25mm
A-SA: 2-acryloyloxyethyl succinate, manufactured by Shin Nakamura Chemical Industry Co., Ltd., molecular weight 216, 90 degree peeling adhesive strength 1.3N / 25mm
EHA: 2-ethylhexyl acrylate, manufactured by Nippon Shokubai Co., Ltd., molecular weight 184.3, 90 degree peeling adhesive strength 4.5N / 25mm
[Epoxy compound]
EXA-830CRP: Bisphenol F type epoxy resin, manufactured by DIC Corporation, molecular weight 316, 90 ° C. peeling adhesive strength 1.1 N / 25 mm
<Photoreaction initiator>
Irgacure 184: 1-Hydroxycyclohexylphenyl ketone, manufactured by BASF Irgacare 290: Tris (4- (4-acetylphenyl) thiophenyl) Sulfonium tetrakis (pentafluorophenyl) borate, manufactured by BASF

(Example 5)
As a polymerizable monomer, 75 parts by weight of methyl methacrylate and 25 parts by weight of methyl acrylate were added to a reaction vessel equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a cooling tube, and 300 parts by weight of ethyl acetate as a polymerization solvent. Added a part. Then, nitrogen gas was blown into the reaction vessel for 30 minutes while stirring to replace the inside of the reaction vessel with nitrogen, and then the inside of the reaction vessel was heated to 80 ° C. while stirring. Leave at 80 ° C. for 30 minutes, and further add t-butylperoxy-2-ethylhexanoate (1 hour half-life temperature: 92.1 ° C., 10-hour half-life temperature: 72.1 ° C.) as a polymerization initiator. 0.5 part by weight was diluted with 5 parts by weight of ethyl acetate, and the obtained polymerization initiator solution was added dropwise to the reaction vessel over 6 hours to react. Further, the reaction solution was cooled to obtain an MMA / MA copolymer having an average molecular weight of 50,000.
The obtained copolymer was used as the thermoplastic resin, and as shown in Table 1, the thermoplastic resin, the reactive diluent (A), the reactive diluent (B) and the photoreaction initiator were added. An adhesive was prepared.

(Examples 10 and 11)
200 g of polyvinyl alcohol having a degree of polymerization of 560 and a degree of saponification of 99 mol% was added to 1800 g of pure water, and the mixture was dissolved by stirring at a temperature of 90 ° C. for about 2 hours. This solution was cooled to 40 ° C., 150 g of hydrochloric acid having a concentration of 35% by weight and 75 g of acetaldehyde were added thereto, and the liquid temperature was maintained at 40 ° C. to carry out an acetalization reaction to precipitate a reaction product.
Then, the liquid temperature was maintained at 40 ° C. for 3 hours to complete the reaction, and the mixture was neutralized, washed with water and dried by a conventional method to obtain a polyvinyl acetal acetal resin powder.
The obtained polyvinyl acetal acetal resin was dissolved in _{DMSO-D 6} ^{(dimethyl sulfoxide) and measured using 13} C-NMR (nuclear magnetic resonance spectrum). As a result, the amount of hydroxyl groups was 25 mol% and the amount of acetal acetal groups was 74. It was mol% and the amount of acetyl group was 1 mol%.

The obtained polyvinyl acetal acetal resin was used as the thermoplastic resin, and as shown in Table 1, the thermoplastic resin, the reactive diluent (A), the reactive diluent (B) and the photoreaction initiator were added. , Made an adhesive.

(Comparative Examples 1 to 3 and 6)
As shown in Table 2, a reactive diluent (A), a reactive diluent (B) and a photoreactive initiator were added to prepare an adhesive.

(Comparative Example 4)
An adhesive made of the polyvinyl butyral resin obtained in Example 1 was prepared.

(Comparative Example 5)
An adhesive made of the polyvinyl acetal resin obtained in Example 8 was prepared.

(Comparative Examples 7 and 8)
As the thermoplastic resin, the polyvinyl butyral resin obtained in Example 1 was used, and as shown in Table 2, the thermoplastic resin, the reactive diluent (B) and the photoreaction initiator were added to prepare an adhesive. did.

(Comparative Example 9)
As the thermoplastic resin, the polyvinyl acetal acetal resin obtained in Example 8 was used, and as shown in Table 2, the thermoplastic resin, the reactive diluent (B) and the photoreaction initiator were added to obtain an adhesive. Made.

<Evaluation>
The adhesives obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 1 and 2.

(Measurement of elastic modulus and tan δ peak temperature)
The adhesives obtained in Examples 1 to 13 and Comparative Examples 1, 2, 4, 5, 7 to 9 were irradiated with ultraviolet rays at ^{an irradiation amount of 3000 mJ / cm 2 using a metal halide UV lamp to obtain a cured product.} It was.
The obtained cured product was subjected to a sample length of 30 mm, a chuck interval of 20 mm, a frequency of 1 Hz, and a heating rate of 5 ° C./min using a dynamic viscoelasticity measuring device DVA-200 (manufactured by IT Measurement Control Co., Ltd.). The dynamic viscoelastic spectrum was measured in the temperature range of 50 to 100 ° C., and the elastic modulus at 50 ° C. and the tan δ peak temperature derived from the thermoplastic resin were confirmed.

(Evaluation of adhesiveness after temporary attachment)
As an adherend, PET film (manufactured by Toyobo Co., Ltd., Cosmo Shine A-4100, thickness 100 μm, untreated surface that is not an easy-adhesion-treated surface is used as an evaluation surface), polarizing plate (manufactured by Nitto Denko Corporation, SEG1425DU), Glass (manufactured by Nippon Test Panel Co., Ltd.) and prism sheet (manufactured by Suntech Opto Co., Ltd., 48 μm prism pitch, thickness 45 μm) were used.
The adhesives obtained in Examples and Comparative Examples were coated on a PET film using a bar coater so as to have a thickness of 20 μm, and further, a PET sheet that had been released from the mold was laminated to obtain a laminate. .. The obtained laminate was irradiated with ultraviolet rays at an irradiation amount of 60 mJ / cm ² using a metal halide UV lamp, and then the PET sheet was peeled off to obtain a PET film with an adhesive layer.
The adherend was placed on the adhesive layer side of the PET film with the adhesive layer, and pressed once back and forth using a 2 kg roller. As for the prism sheet, only the outward path was pressed using a 30 g roller.
Then, ultraviolet rays were irradiated with an irradiation amount of 3000 mJ / cm ² using a metal halide lamp to obtain a two-stage cured sample.
The obtained sample was subjected to a 90-degree peel test under the condition of a tensile speed of 300 mm / min using a tensile tester to measure the adhesive strength, and the adhesiveness after temporary attachment was evaluated according to the following criteria.

<PET-PET>
⊚: The adhesive strength was 14 N or more.
◯: The adhesive strength was 11 N or more and less than 14 N.
Δ: The adhesive strength was 8 N or more and less than 11 N.
X: The adhesive strength was less than 8N.
<PET-polarizing plate>
⊚: The adhesive strength was 10 N or more.
◯: The adhesive strength was 8 N or more and less than 10 N.
Δ: The adhesive strength was 6 N or more and less than 8 N.
X: The adhesive strength was less than 6N.
<PET-Glass>
⊚: The adhesive strength was 10 N or more.
◯: The adhesive strength was 8 N or more and less than 10 N.
Δ: The adhesive strength was 4 N or more and less than 8 N.
X: The adhesive strength was less than 4N.
<PET-Prism sheet>
⊚: The adhesive strength was 1N or more.
◯: The adhesive strength was 0.7 N or more and less than 1 N.
Δ: The adhesive strength was 0.5 N or more and less than 0.7 N.
X: The adhesive strength was less than 0.5N.

(Adhesion evaluation)
As the adherend, the same material as (evaluation of adhesiveness after temporary attachment) was used.
For the PET film, the polarizing plate and the prism sheet, the adhesives obtained in Examples and Comparative Examples were applied onto the PET film using a bar coater so as to have a thickness of 20 μm, and the PET film and the adherend were coated. The adherends were laminated so as to sandwich the adhesive between the and, to prepare a laminated body. The obtained laminate was irradiated with ultraviolet rays at an irradiation amount of 3000 mJ / cm ² using a metal halide UV lamp, and then cut into 25 mm × 150 mm to obtain a sample.
For glass, the adhesive obtained on a glass of 50 mm × 150 mm was coated with a bar coater so as to have a thickness of 20 μm, and a PET film cut into 25 mm × 150 mm was layered on the glass to obtain 30 g. A laminate was produced by pressurizing with a roller. The obtained laminate was irradiated with ultraviolet rays at an irradiation amount of 3000 mJ / cm ^{2 using a metal halide lamp to obtain a sample.}
The obtained sample was subjected to a 90-degree peel test under the condition of a tensile speed of 300 mm / min using a tensile tester to measure the adhesive strength, and the adhesiveness was evaluated according to the following criteria.

<PET-PET>
⊚: The adhesive strength was 12 N or more.
◯: The adhesive strength was 8 N or more and less than 12 N.
Δ: The adhesive strength was 6 N or more and less than 8 N.
X: The adhesive strength was less than 6N.
<PET-polarizing plate>
⊚: The adhesive strength was 7 N or more.
◯: The adhesive strength was 5 N or more and less than 7 N.
Δ: Adhesive strength was 3N or more and less than 5N.
X: The adhesive strength was less than 3N.
<PET-Glass>
⊚: The adhesive strength was 12 N or more.
◯: The adhesive strength was 9 N or more and less than 12 N.
Δ: The adhesive strength was 6 N or more and less than 9 N.
X: The adhesive strength was less than 6N.
<PET-Prism sheet>
⊚: The adhesive strength was 1.4 N or more.
◯: The adhesive strength was 0.9 N or more and less than 1.4 N.
Δ: The adhesive strength was 0.7 N or more and less than 0.9 N.
X: The adhesive strength was less than 0.7N.

(Brightness deterioration evaluation)
On the MUTOH light board, put the unbonded PET film and prism sheet on top of each other and place them in the center of the light source. Using BM-9 manufactured by TOPCON as a luminance meter, the distance between the light source and the luminance meter is set to 350 mm. A luminance meter was placed in the center of the light source, and the luminance before bonding was measured. After that, the brightness of the sample using the prism sheet obtained in (Adhesion Evaluation) was measured in the same manner.
The brightness deterioration was calculated by the following formula and evaluated according to the following criteria.
(Brightness deterioration) = (Brightness before bonding-Brightness of sample) / (Brightness before bonding) x 100 (%)
⊚: Luminance deterioration was less than 10%.
◯: The brightness deterioration was 10% or more and less than 12%.
Δ: Luminance deterioration was 12% or more and less than 16%.
X: Luminance deterioration was 16% or more.

(Haze evaluation)
The adhesives obtained in Examples and Comparative Examples were applied to a glass of 10 cm × 7.0 cm and a thickness of 1 mm using a dispenser so that the thickness after coating was 100 μm, and the other surface was 10 cm. It was attached to glass having a thickness of × 7.0 cm and a thickness of 1 mm to obtain a glass / adhesive / glass constituent (glass-glass constituent).

The haze value of the obtained structure was measured using a color haze meter (manufactured by Murakami Color Technology Research Institute) in accordance with JIS K 5600.
⊚: Haze was less than 0.5%.
〇: The haze was 0.5% or more and less than 1%.
Δ: The haze was 1% or more and less than 2%.
X: The haze was 2% or more.

According to the present invention, it is possible to exhibit surface tackiness to improve temporary adhesion, and further, it is possible to exhibit excellent adhesive force by enhancing adhesion even after temporary attachment, and it is excellent in transparency. In particular, it is possible to provide an adhesive capable of suppressing deterioration of brightness when used for bonding optical films.

Claims (10)

Containing a thermoplastic resin, a reactive diluent (A) and a photoreaction initiator,
The reactive diluent (A) is characterized in that the 90-degree peel-off adhesive strength measured in accordance with JIS K 6851-1: 1999 when used for bonding PET to each other is 5.5 N / 25 mm or more. Adhesive to be. The adhesive according to claim 1, further comprising a reactive diluent (B) other than the reactive diluent (A). The adhesive according to claim 1 or 2, wherein the content of the thermoplastic resin is 5 to 40% by weight. The adhesive according to claim 1, 2 or 3, wherein the content of the reactive diluent (A) is 30 to 85% by weight. The adhesive according to claim 1, 2, 3 or 4, wherein the reactive diluent (A) contains an epoxy compound. The adhesive according to claim 1, 2, 3, 4 or 5, wherein the thermoplastic resin is a polyvinyl acetal resin. The adhesive according to claim 6, wherein the polyvinyl acetal resin is a polyvinyl acetal acetal resin. Modulus at a dynamic viscoelasticity measurement of dose 3000 mJ / cm cured product obtained by curing by irradiation ² of the active energy ray is 1 × ¹⁰ 5 Pa or more and, tan [delta peak temperature derived from the thermoplastic resin is 60 ° C. or higher The adhesive according to claim 7, wherein the adhesive is. The adhesive according to claim 1, 2, 3, 4, 5, 6, 7 or 8, which is used for adhering plastics. The adhesive according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, which is used for adhering an optical film.