UV-curing adhesive composition and adhesive

Abstract

The purpose of the present invention is to provide a UV-curable adhesive composition having excellent printability, UV reactivity in the presence of oxygen, and adhesiveness with respect to a variety of types of base materials. Another purpose of the present invention is to provide an adhesive obtained using the UV-curable adhesive composition. The present invention is a UV-curable adhesive composition containing (A) a nitrogen-containing monomer, (B) a monofunctional (meth)acrylate monomer, (C) a crosslinking component, (D) a photopolymerization initiator, and (E) a thermoplastic resin that is not reactive with respect to the (A) nitrogen-containing monomer or the (B) monofunctional (meth)acrylate monomer, the UV-curable adhesive composition being such that when the composition is applied onto a base material at a thickness of 150 μm and irradiated in an atmospheric environment with UV light having a wavelength of 315-480 nm at an irradiance of 90 mW / cm2 and an irradiation amount of 1350 mJ / cm2, the obtained cured product is such that the reaction rates of the atmosphere-side surface and the base material-side surface are both 80% or above.

Description

[Technical Field]

[0001] The present invention relates to an ultraviolet-curable adhesive composition that exhibits excellent printability, ultraviolet reactivity in the presence of oxygen, and adhesion to various substrates. The present invention also relates to an adhesive made using the ultraviolet-curable adhesive composition. [Background technology]

[0002] Adhesives are used to bond electronic components inside electronic devices such as smartphones and PCs. In a typical method of bonding with adhesives, an adhesive sheet is first prepared with separators placed on both sides of the adhesive, and then the adhesive sheet is cut to the desired shape. After that, one separator is peeled off from the cut adhesive sheet, and one side of the exposed adhesive is bonded to the first adherend, and then the other separator is peeled off, and the other side of the exposed adhesive is bonded to the second adherend. In this method, a portion of the adhesive sheet is discarded after cutting, resulting in waste. Also, air bubbles could get trapped in the bonded surface.

[0003] In response to this, a method is being considered in which the adhesive composition is printed into the desired shape and then bonded to the substrate without the need to create an adhesive sheet. This method can reduce waste generation and prevent air bubbles from forming on the bonded surface.

[0004] For example, Patent Document 1 describes a radiation-curable adhesive composition that enables fine patterning and exhibits high adhesion to various substrates such as metals and plastics, comprising 10 to 70% by weight of an aromatic ring-free ethylenically unsaturated monomer, 1 to 10% by weight of a photopolymerization initiator, and 10 to 55% by weight of a crosslinking agent, wherein the aromatic ring-free ethylenically unsaturated monomer contains 10 to 45% by weight of an alkyl (meth)acrylate having 8 to 18 carbon atoms in the alkyl group, and the crosslinking agent contains 10 to 50% by weight of a urethane poly(meth)acrylate having a weight-average molecular weight of 20,000 to 100,000.

[0005] Furthermore, Patent Document 2 describes a photocurable adhesive composition that provides a laminate having adhesive strength equivalent to that in the absence of oxygen, even when irradiated with light in the presence of oxygen, and includes (A) a (meth)acrylate oligomer, (B) a monofunctional (meth)acrylate monomer, (C) a bifunctional to tetrafunctional (meth)acrylate monomer, (D) a photoreaction initiator, (E) a tackifier with a softening point of 70 to 150°C, and (F) a liquid plasticizer. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2013-216742 [Patent Document 2] International Publication No. 2016 / 163152 [Overview of the project] [Problems that the invention aims to solve]

[0007] As described above, the method of printing the adhesive composition into the desired shape and then bonding it to the substrate, without creating an adhesive sheet, suppresses the generation of waste and prevents air bubbles from forming on the bonded surface. On the other hand, while UV curing is preferable as a method for curing the adhesive composition to avoid heating the substrate, if the adhesive composition is exposed without being covered by a separator during curing, sufficient UV reactivity may not be obtained, resulting in insufficient adhesion to the substrate. Therefore, there was still room for improvement in order to provide a UV-curable composition for printing that is excellent in printability, UV reactivity, and adhesion to various substrates.

[0008] The present invention aims to provide an ultraviolet-curable adhesive composition that exhibits excellent printability, ultraviolet reactivity in the presence of oxygen, and adhesion to various substrates. Furthermore, the present invention aims to provide an adhesive using the ultraviolet-curable adhesive composition. [Means for solving the problem]

[0009] Disclosure 1 is an ultraviolet-curable adhesive composition comprising (A) a nitrogen-containing monomer, (B) a monofunctional (meth)acrylate monomer, (C) a crosslinking component, (D) a photopolymerization initiator, and (E) a thermoplastic resin that does not react with the (A) nitrogen-containing monomer and the (B) monofunctional (meth)acrylate monomer, wherein the composition is coated onto a substrate to a thickness of 150 μm and exposed to ultraviolet light with a wavelength of 315 nm to 480 nm at an irradiance of 90 mW / cm² in an atmospheric environment. 2 , irradiation amount 1350mJ / cm 2 This is an ultraviolet-curable adhesive composition in which the reaction rate of both the air-facing side and the substrate-facing side of the cured product obtained by irradiation under the specified conditions is 80% or higher. Disclosure 2 is the UV-curable adhesive composition of Disclosure 1, wherein the content of (A) nitrogen-containing monomer is 10 to 35% by weight. Disclosure 3 is an ultraviolet-curable adhesive composition of Disclosure 1 or 2, further containing an antifoaming agent. Disclosure 4 is an ultraviolet-curable adhesive composition of Disclosure 1, 2, or 3, wherein the glass transition temperature of the cured product is 20°C to -30°C. Disclosure 5 is an ultraviolet-curable adhesive composition of Disclosure 1, 2, 3, or 4 used in screen printing. Disclosure 6 is an adhesive obtained by printing an ultraviolet-curable adhesive composition of Disclosure 1, 2, 3, 4, or 5 and irradiating it with ultraviolet light. Disclosure 7 is an adhesive sheet comprising a substrate and an adhesive layer provided on at least one side of the substrate, the adhesive layer being made of an ultraviolet-curable adhesive composition of Disclosure 1, 2, 3, 4, or 5. Disclosure 8 is an adhesive sheet of Disclosure 7, wherein the adhesive layer is partially disposed on the substrate. Disclosure 9 is a laminate in which a first adherend and a second adherend are bonded together via the adhesive layer contained in the adhesive sheet of Disclosure 7 or 8. Disclosure 10 is a method for manufacturing a laminate, which involves applying an ultraviolet-curable adhesive composition of Disclosure 1, 2, 3, 4, or 5 onto a first adherend, forming an adhesive layer by exposure, and then attaching a second adherend onto the adhesive layer to produce a laminate. Disclosure 11 is a method for manufacturing a laminate of Disclosure 10, wherein the method for applying the ultraviolet-curable adhesive composition is inkjet printing, screen printing, spray coating, spin coating, gravure offset, or reverse offset printing, and the ultraviolet-curable adhesive composition is partially applied on the first adherend. The present invention will be described in detail below.

[0010] The inventors of the present invention have found that it is difficult to obtain sufficient ultraviolet reactivity when the conventional adhesive composition is exposed without being coated with a separator during curing. Therefore, as a result of repeated studies, it has been found that (A) the use of a nitrogen-containing monomer can improve the ultraviolet reactivity in the presence of oxygen. Further, together with (A) the nitrogen-containing monomer, (B) a monofunctional (meth)acrylate monomer, (C) a crosslinking component, and (E) a thermoplastic resin having no reactivity with respect to the above (A) nitrogen-containing monomer and the above (B) monofunctional (meth)acrylate monomer are used, it has been found that printability and adhesion to various substrates can also be ensured. Furthermore, it has been found that when the reaction rates of the air-side surface and the substrate-side surface in the cured product are both adjusted to 80% or more, the ultraviolet reactivity in the presence of oxygen and the adhesion to various substrates are excellent, and the present invention has been completed.

[0011] The above ultraviolet-curable adhesive composition contains (A) a nitrogen-containing monomer. The nitrogen-containing monomer is not particularly limited as long as it has a nitrogen atom in the molecule and a polymerizable group, but an amide compound having a vinyl group is preferable, a cyclic amide compound having a vinyl group is more preferable, and a compound having a lactam structure is even more preferable.

[0012] Examples of the amide compound having a vinyl group include N-vinylacetamide, (meth)acrylamide compounds, and the like. Examples of the (meth)acrylamide compounds include N,N-dimethyl(meth)acrylamide, N-(meth)acryloylmorpholine, N-hydroxyethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, and the like.

[0013] Examples of the cyclic amide compound having a vinyl group include compounds represented by the following formula (1).

[0014]

Chemical formula

[0015] In formula (1), n represents an integer of 2 to 6.

[0016] Examples of the compound represented by the above formula (1) include N-vinyl-2-pyrrolidone, N-vinyl-ε-caprolactam, etc. Among them, N-vinyl-ε-caprolactam is preferred.

[0017] The above nitrogen-containing monomer preferably includes a monomer having a negative e value. Examples of the nitrogen-containing monomer having a negative e value include N-vinylacetamide (e value = -1.57), N-vinyl-ε-caprolactam (e value = -1.18), N-vinyl-2-pyrrolidone (e value = -1.62), N,N-dimethyl(meth)acrylamide (e value = -0.26), etc.

[0018] The content of the above nitrogen-containing monomer may be adjusted so that the reaction rates of both the air-side surface and the substrate-side surface in the cured product are 80% or more. Specifically, with respect to 100% by weight of the ultraviolet-curable adhesive composition, the content of the nitrogen-containing monomer is preferably 10 to 35% by weight. When the content of the above nitrogen-containing monomer is 10% by weight or more, the ultraviolet reactivity in the presence of oxygen can be improved, and it becomes easy to make the reaction rates of both the air-side surface and the substrate-side surface in the cured product 80% or more. When the content of the above nitrogen-containing monomer is 35% by weight or less, the resulting adhesive has excellent adhesion to various substrates. A more preferable upper limit of the content of the above nitrogen-containing monomer is 25% by weight.

[0019] The above ultraviolet-curable adhesive composition contains a (B) monofunctional (meth)acrylate monomer. In this specification, "(meth)acrylic" means acrylic or methacrylic, "(meth)acrylate monomer" means a monomer having a (meth)acryloyl group, and "(meth)acryloyl" means acryloyl or methacryloyl. In this specification, "monofunctional" means that there is one (meth)acryloyl group in one monomer molecule. Monomers having a (meth)acryloyl group and nitrogen are treated as (A) nitrogen-containing monomers, not as (B) monofunctional (meth)acrylate monomers.

[0020] Examples of the above-mentioned (meth)acrylate monomers include (meth)acrylic acid ester compounds and epoxy (meth)acrylates. In this specification, "(meth)acrylate" means acrylate or methacrylate, and "epoxy (meth)acrylate" refers to a compound obtained by reacting all epoxy groups in an epoxy compound with (meth)acrylic acid.

[0021] Examples of the monofunctional (meth)acrylic acid ester compounds mentioned above include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, n-heptyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, isomiristyl (meth)acrylate, stearyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Rate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, bicyclopentenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, methoxyethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, tetrahydrofurfuryl alcohol acrylic acid polymer ester, ethyl carbitol (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-Octafluoropentyl (meth)acrylate, imido (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalate, 2-(meth)acryloyloxyethyl 2-hydroxypropyl phthalate, 2-(meth)acryloyloxyethyl phosphate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, 2-(((butylamino)carbonyl)oxy)ethyl (meth)acrylate, (3-propyloxetan-3-yl)methyl (meth)acrylate, (3-butyloxetan-3-yl)methyl (meth)acrylate, (3-ethyloxetan-3-yl)ethyl (meth)acrylate Examples include (3-ethyloxetan-3-yl)propyl (meth)acrylate, (3-ethyloxetan-3-yl)butyl (meth)acrylate, (3-ethyloxetan-3-yl)pentyl (meth)acrylate, (3-ethyloxetan-3-yl)hexyl (meth)acrylate, γ-butyrolactone (meth)acrylate, (2,2-dimethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (2-methyl-2-isobutyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, (2-cyclohexyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, and cyclic trimethylolpropane formal acrylate.

[0022] Examples of the epoxy (meth)acrylates mentioned above include bisphenol A type epoxy (meth)acrylate, bisphenol F type epoxy (meth)acrylate, bisphenol E type epoxy (meth)acrylate, and caprolactone-modified versions thereof.

[0023] The preferred lower limit for the content of the monofunctional (meth)acrylate monomer in 100 parts by weight of the above UV-curable adhesive composition is 20 parts by weight, and the preferred upper limit is 70 parts by weight. A content of 20 parts by weight or more of the monofunctional (meth)acrylate monomer results in an adhesive with excellent adhesion to various substrates. A content of 70 parts by weight or less of the monofunctional (meth)acrylate monomer results in an adhesive with excellent properties other than adhesion. A more preferred lower limit for the content of the monofunctional (meth)acrylate monomer is 28 parts by weight, and a more preferred upper limit is 60 parts by weight.

[0024] The above UV-curable adhesive composition contains (C) a crosslinking component. The above crosslinking component is not particularly limited as long as it is a compound having two or more bonding functional groups in one molecule, but it is preferable that it is reactive to the above (A) nitrogen-containing monomer and the above (B) monofunctional (meth)acrylate monomer, or that it is reactive to the above (A) nitrogen-containing monomer, the above (B) monofunctional (meth)acrylate monomer and (E) thermoplastic resin.

[0025] The above (C) crosslinking component preferably has at least one bonding functional group selected from the group consisting of isocyanate group, epoxy group, aldehyde group, hydroxyl group, amino group, (meth)acrylate group, and vinyl group. If it has these bonding functional groups, it can form crosslinked bonds with sufficient density during curing.

[0026] The crosslinking component (C) above preferably contains a (meth)acrylate monomer that has a gel fraction of 80% or more when homopolymerized. Using such a (meth)acrylate monomer improves the cohesive strength of the UV-curable adhesive composition, thereby improving the printability of the composition and the adhesion of the resulting adhesive.

[0027] The (C) crosslinking component described above is preferably composed of a (meth)acrylate monomer having a viscosity of 10,000 cps or more at 25°C. Furthermore, the (C) crosslinking component described above is preferably composed of a bifunctional (meth)acrylate monomer. Using such a (meth)acrylate monomer improves the cohesive strength of the UV-curable adhesive composition, thereby improving the printability of the composition and the adhesion of the resulting adhesive.

[0028] Specific examples of the crosslinking component (C) above include, for example, radically polymerizable polyfunctional oligomers or monomers, polymers having crosslinkable functional groups, and the like.

[0029] Examples of the above-mentioned radically polymerizable polyfunctional oligomers or monomers include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, or similar methacrylates. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylates, and similar methacrylates. These radically polymerizable polyfunctional oligomers or monomers may be used individually or in combination of two or more.

[0030] The content of the (C) crosslinking component is preferably 0.1 to 25% by weight in 100% by weight of the total amount of the (A) nitrogen-containing monomer, the (B) monofunctional (meth)acrylate monomer, and the (C) crosslinking component. Having the (C) crosslinking component content within this range moderately improves the cohesive strength of the UV-curable adhesive composition, thereby improving the printability of the composition and the adhesion of the resulting adhesive. A more preferable lower limit for the (C) crosslinking component content is 2% by weight, and a more preferable upper limit is 15% by weight.

[0031] The above UV-curable adhesive composition contains (D) a photopolymerization initiator. As the above-mentioned photopolymerization initiator, a photoradical polymerization initiator is preferably used. The photopolymerization initiator and the photoradical polymerization initiator may be used alone, or two or more may be used in combination.

[0032] Examples of the above-mentioned photoradical polymerization initiators include benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin ether compounds, and thioxanthone compounds. Examples of alkylphenone compounds include acetophenone compounds. When two or more photoradical polymerization initiators are used in combination, the adhesion of the resulting adhesive is improved, so it is preferable to use alkylphenone compounds and acylphosphine oxide compounds in combination.

[0033] Examples of the above-mentioned photoradical polymerization initiators include, specifically, 1-hydroxycyclohexylphenyl ketone, 2-benzyl-2-(dimethylamino)-1-(4-(morpholino)phenyl)-1-butanone, 2-(dimethylamino)-2-((4-methylphenyl)methyl)-1-(4-(4-morpholinyl)phenyl)-1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2- Examples include methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 1-(4-(2-hydroxyethoxy)-phenyl)-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-(phenylthio)phenyl)-1,2-octanedione 2-(O-benzoyloxime), 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether. When two or more of the above photoradical polymerization initiators are used in combination, the adhesion of the resulting adhesive is improved, so it is preferable to use 1-hydroxycyclohexylphenyl ketone as the alkylphenone compound and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and / or 2,4,6-trimethylbenzoyldiphenylphosphine oxide as the acylphosphine oxide compound.

[0034] The preferred lower limit for the content of the above-mentioned photopolymerization initiator is 0.2 parts by weight and the preferred upper limit is 10 parts by weight, based on 100 parts by weight of the total amount of the above-mentioned nitrogen-containing monomer (A) and monofunctional (meth)acrylate monomer (B). When the content of the above-mentioned photopolymerization initiator is within this range, the UV-curable adhesive composition maintains excellent storage stability while exhibiting superior UV curability. Furthermore, when the content of the above-mentioned photopolymerization initiator is 0.2 parts by weight or more, the adhesion of the resulting adhesive is further improved. A more preferred lower limit for the content of the above-mentioned photopolymerization initiator is 0.5 parts by weight, an even more preferred lower limit is 1.0 part by weight, a particularly preferred lower limit is 1.5 parts by weight, a more preferred upper limit is 5 parts by weight, an even more preferred upper limit is 3 parts by weight, a particularly preferred upper limit is 2.5 parts by weight, and the most preferred upper limit is 2 parts by weight. Note that if two or more types of photopolymerization initiators are included, the content of the photopolymerization initiators refers to the total content of all included photopolymerization initiators.

[0035] The above UV-curable adhesive composition contains (E) a thermoplastic resin that does not react to the above (A) nitrogen-containing monomer and the above (B) monofunctional (meth)acrylate monomer. As the above thermoplastic resin, a compound that does not contain reactive double bonds or a compound that contains reactive double bonds but does not substantially exhibit photopolymerization reactivity can be used. The above thermoplastic resin may also be reactive to triggers such as heat and moisture after the above UV-curable adhesive composition has been photopolymerized. For example, it may contain an epoxy resin and be cured by heat, or it may contain an isocyanate compound and be cured by moisture or alcohol.

[0036] Examples of the thermoplastic resins mentioned above include solvent-free acrylic polymers.

[0037] Examples of the solvent-free acrylic polymers mentioned above include polymers of at least one monomer selected from alkyl (meth)acrylate esters having 1 to 20 carbon atoms in the alkyl group, or copolymers of the monomer and other copolymerizable monomers. Examples of commercially available solvent-free acrylic polymers include the ARUFON-UP1000 series, UH2000 series, and UC3000 series from Toagosei Co., Ltd., and the acrylic block copolymers Clarity LA series and LK series from Kuraray Co., Ltd.

[0038] The content of the thermoplastic resin is preferably 0.1 to 140 parts by weight per 100 parts by weight of the total amount of the nitrogen-containing monomer (A) and the monofunctional (meth)acrylate monomer (B). This range of thermoplastic resin content improves the viscosity of the UV-curable adhesive composition, allowing for the formation of a thick coating film, resulting in excellent printability and suppressing a decrease in tackiness at high temperatures. A more preferable lower limit for the thermoplastic resin content is 10 parts by weight, and a more preferable upper limit is 90 parts by weight.

[0039] The above UV-curable adhesive composition may contain plasticizers such as organic acid esters, organic phosphate esters, and organic phosphite esters.

[0040] Examples of the plasticizers mentioned above include organic acid ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, and phosphate plasticizers such as organic phosphate plasticizers and organic phosphite plasticizers. Among these, organic acid ester plasticizers are preferred. These plasticizers may be used individually or in combination of two or more.

[0041] Examples of the above-mentioned organic acid esters include monobasic organic acid esters and polybasic organic acid esters. The monobasic organic acid esters mentioned above are not particularly limited. For example, examples include glycol esters obtained by the reaction of monobasic organic acids such as butyric acid, isobutyric acid, caproic acid, 2-ethylbutyric acid, heptylic acid, n-octylic acid, 2-ethylhexylic acid, pelargonic acid (n-nonylic acid), and decylic acid with glycols such as triethylene glycol, tetraethylene glycol, and tripropylene glycol. The above-mentioned polybasic organic acid esters are not particularly limited, and examples include ester compounds obtained by the reaction of polybasic organic acids such as adipic acid, sebacic acid, and azelaic acid with alcohols having a linear or branched structure with 4 to 8 carbon atoms.

[0042] The above organic acid esters specifically include, for example, triethylene glycol-di-2-ethyl butyrate (3GH), triethylene glycol-di-2-ethylhexanoate (3GO), triethylene glycol dicaprylate, triethylene glycol di-n-octanoate, and triethylene glycol-di-n-heptanoate (3G7). Also, examples include tetraethylene glycol-di-n-heptanoate (4G7), tetraethylene glycol-di-2-ethylhexanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol-di-2-ethyl butyrate, and 1,3-propylene glycol-di-2-ethyl butyrate. Furthermore, examples include 1,4-butylene glycol-di-2-ethyl butyrate, diethylene glycol-di-2-ethyl butyrate, diethylene glycol-di-2-ethylhexanoate, and dipropylene glycol-di-2-ethyl butyrate. Other examples include triethylene glycol di-2-ethylpentanoate, tetraethylene glycol di-2-ethyl butyrate (4GH), diethylene glycol dicapriate, dihexyl adipate (DHA), dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, and heptylnonyl adipate. Other examples include oil-modified sebacate alkyd, mixtures of phosphate esters and adipate esters, and mixed adipate esters made from alkyl alcohols having 4 to 9 carbon atoms and cyclic alcohols having 4 to 9 carbon atoms.

[0043] Examples of the above-mentioned organic phosphate esters or organic phosphite esters include compounds obtained by the condensation reaction of phosphoric acid or phosphite with an alcohol. Among these, compounds obtained by the condensation reaction of an alcohol having 1 to 12 carbon atoms with phosphoric acid or phosphite are preferred. Examples of the above-mentioned alcohols having 1 to 12 carbon atoms include methanol, ethanol, butanol, hexanol, 2-ethylbutanol, heptanol, octanol, 2-ethylhexanol, decanol, dodecanol, butoxyethanol, butoxyethoxyethanol, and benzyl alcohol. Examples of the above-mentioned organic phosphate esters or organic phosphite esters include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, tri(2-ethylhexyl) phosphate, tri(butoxyethyl) phosphate, tri(2-ethylhexyl) phosphite, isodecylphenyl phosphate, triisopropyl phosphate, and the like.

[0044] The above UV-curing adhesive composition may contain tackifiers such as rosin resins and terpene resins.

[0045] Examples of the rosin-based resins mentioned above include rosindiol. The above-mentioned rosin diol is not particularly limited as long as it is a rosin-modified diol having two rosin skeletons and two hydroxyl groups in its molecule. Diols containing a rosin component in their molecule are called rosin polyols, and these include polyether types, such as polypropylene glycol (PPG), in which the skeleton excluding the rosin component is made, and polyester types, such as condensed polyester polyols, lactone polyester polyols, and polycarbonate diols. Examples of the above-mentioned rosin diols include rosin esters obtained by reacting rosin with a polyhydric alcohol, epoxy-modified rosin esters obtained by reacting rosin with an epoxy compound, and modified rosins having hydroxyl groups, such as polyethers having a rosin skeleton. These can be produced by conventionally known methods.

[0046] Examples of the rosin components mentioned above include abietic acid and its derivatives such as pimaric acid-type resin acids including dehydroabietic acid, dihydroabietic acid, tetrahydroabietic acid, diabietic acid, neoabietic acid, and levopimalic acid, hydrogenated rosin obtained by hydrogenating these, 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, KE-604, and D-6250, all manufactured by Arakawa Chemical Industries, Ltd.

[0047] Examples of the terpene resins mentioned above include terpene phenol resins. The above-mentioned terpene phenol resins are copolymers of terpene resins, which are essential oil components obtained from natural products such as pine resin and orange peel, and phenol, and also include partially hydrogenated terpene phenol resins in which at least a portion of the copolymer is hydrogenated, or fully hydrogenated terpene phenol resins in which the copolymer is completely hydrogenated. Here, fully hydrogenated terpene phenol resins are terpene resins (tackifying resins) obtained by substantially completely hydrogenating a terpene phenol resin, and partially hydrogenated terpene phenol resins are terpene resins (tackifying resins) obtained by partially hydrogenating a terpene phenol resin. Terpene phenol resins have double bonds derived from terpenes and aromatic ring double bonds derived from phenols. Therefore, fully hydrogenated terpene phenol resins mean tackifying resins in which both the terpene and phenol moieties are completely or almost completely hydrogenated, and partially hydrogenated terpene phenol resins mean terpene phenol resins in which the degree of hydrogenation of those moieties is not complete but partial. The hydrogenation method and reaction form are not particularly limited. Examples of commercially available terpene phenol resins include YS Polystar NH (fully hydrogenated terpene phenol resin) manufactured by Yasuhara Chemical Co., Ltd.

[0048] The above UV-curing adhesive composition may contain an antifoaming agent. The antifoaming agent is not particularly limited and examples include silicone-based antifoaming agents, acrylic polymer-based antifoaming agents, vinyl ether polymer-based antifoaming agents, olefin polymer-based antifoaming agents, and so on.

[0049] The above UV-curable adhesive composition may further contain various known additives such as viscosity modifiers, silane coupling agents, sensitizers, thermosetting agents, curing retarders, antioxidants, storage stabilizers, dispersants, and fillers, to the extent that they do not hinder the objectives of the present invention. Furthermore, from the viewpoint of preventing a decrease in UV reactivity, the above UV-curable adhesive composition preferably contains substantially no organic solvents, and specifically, it is preferable that the content of organic solvents is 1.5% by weight or less per 100% by weight of the UV-curable adhesive composition.

[0050] In this invention, the above UV-curable adhesive composition is coated onto a substrate to a thickness of 150 μm, and exposed to ultraviolet light with a wavelength of 315 nm to 480 nm at an irradiance of 90 mW / cm² in an atmospheric environment. 2 , irradiation amount 1350mJ / cm 2 The reaction rates of both the surface facing the atmosphere (front) and the surface facing the substrate (back) of the cured product obtained by irradiation under these conditions are 80% or higher. At that time, the total irradiance is 90 mW / cm². 2 and irradiation dose of 1350 mJ / cm² 2If so, it may be irradiated with a plurality of wavelengths in the wavelength range of 315 nm to 480 nm. As the above base material, a PET film having a release treatment on the surface is preferably used. The above conditions are such that after applying the ultraviolet curable adhesive composition on the base material, ultraviolet irradiation is performed in the presence of oxygen without covering the coated upper surface with a separator. Therefore, the reaction rate of the surface on the atmosphere side (also referred to as "surface reaction rate" in this specification) reflects the ultraviolet reactivity in the presence of oxygen. On the other hand, since the coating film has a thickness of 150 μm, the reaction rate of the surface on the base material side (back surface) (also referred to as "back surface reaction rate" in this specification) reflects the ultraviolet reactivity under the condition where oxygen is absent. If a reaction rate of 80% or more is obtained on both the surface on the atmosphere side (surface) and the surface on the base material side (back surface), it can be said that the ultraviolet reactivity in the presence of oxygen is sufficiently high, and a method of printing the adhesive composition into a desired shape and then bonding it to an adherend can be applied.

[0051] Incidentally, the above surface reaction rate can be determined by optically measuring the structure derived from the monomer or the structure derived from the polymer in the cured product from the atmosphere side (front side). The above back surface reaction rate can be determined by optically measuring the structure derived from the monomer or the structure derived from the polymer in the cured product from the base material side (back side). As the optical measurement, for example, a method of obtaining the amount of vinyl groups in the cured product from the absorbance value at 810 cm -1 in the IR spectrum obtained by the ATR method (Attenuated Total Reflection: total reflection measurement method) can be used.

[0052] Specifically, the measurement of the above surface reaction rate and back surface reaction rate can be performed according to the following procedure. (Preparation of cured product) The above ultraviolet curable adhesive composition is applied onto a PET sheet having a single-sided release treatment as a base material with an applicator so as to have a thickness of 150 μm. Then, in the atmosphere environment without sealing the coated upper surface, using an ultraviolet irradiation device, the UV irradiance at a wavelength of 365 nm is 30 mW / cm 2 and the UV irradiance at a wavelength of 405 nm is 60 mW / cm 2Set it so that the irradiation energy is 1350 mJ / cm². 2 By irradiating the adhesive with ultraviolet light, the ultraviolet-curable adhesive composition is cured to obtain a cured product.

[0053] (Measurement of surface reaction rate and back surface reaction rate) Figures 1 and 2 are diagrams illustrating the calculation methods for surface reaction rate and back surface reaction rate. Figure 1 explains the sample preparation method and the object to be measured, and Figure 2 explains the method for calculating the surface reaction rate and back surface reaction rate from the obtained IR spectrum. The cured sample prepared as described above (cured in an atmospheric environment without sealing the coated surface; see Figure 1(a)) is referred to as "Cured Product A," and the sample prepared by irradiating with ultraviolet (UV) light in the same manner as Cured Product A, except that the ultraviolet-curable adhesive composition 10 is sandwiched between PET sheets 20 (see Figure 1(b)), is referred to as "Cured Product B." First, place approximately 0.3g of cured material A onto an aluminum pan. Gently add a mixed solvent containing THF:acetone:ethanol in a weight ratio of 8:1:1, taking care not to cause the cured material sample to splatter, and allow it to swell for about 2 hours. Then, dry it at 110°C for 30 minutes, 170°C for 1 hour, and 190°C for 30 minutes. After drying, confirm that the mixed solvent has completely evaporated. Finally, weigh the aluminum pan and the dried sample, and calculate the overall reaction rate using the following formula. Overall reaction rate [%] = 100 - (Total weight of aluminum pan and sample after drying - Weight of aluminum pan before drying) / (Total weight of aluminum pan and sample before drying - Weight of aluminum pan before drying) × 100

[0054] Next, the IR spectra (infrared absorption spectra) shown in Figure 2 were measured on the front and back surfaces of the cured material A using the ATR method with a Fourier transform infrared spectrometer, at 810 cm⁻¹. -1 Obtain the absorbance values. The obtained values ​​will be designated as "absorbance without PET (front side)" and "absorbance without PET (back side)," respectively. Furthermore, regarding the irradiated surface (surface) of cured material B during curing, after peeling off the PET sheet, the IR spectrum shown in Figure 2 was measured similarly using the ATR method, and the 810 cm⁻¹ spectrum was measured. -1Obtain the absorbance value. The obtained value will be called "Absorbance with PET (Surface)". From these values ​​and the overall reaction rate mentioned above, the surface reaction rate and the back surface reaction rate are calculated using the following formula. Surface reaction rate [%] = Absorbance without PET (surface) / Absorbance with PET (surface) Backside reaction rate [%] = Absorbance without PET (backside) / Absorbance with PET (front) Here, "absorbance without PET (front) / absorbance with PET (front)" and "absorbance without PET (back) / absorbance with PET (front)" are obtained by measuring the UV-curable adhesive composition before curing at 810 cm². -1 This refers to the magnitude of the absorbance without PET (front) and the absorbance without PET (back) when the absorbance of the surface is set to 0% (minimum value) and the absorbance with PET is set to 100% (maximum value). For example, "absorbance without PET (front) / absorbance with PET (front)" represents the reaction rate X in Figure 2 and is expressed by the following formula. Response rate X = B / A × 100 A = |ABS.M - ABS.0| B = |ABS.D - ABS.0|

[0055] To adjust the surface reaction rate and back surface reaction rate of the above UV-curable adhesive composition to the above range, the UV reactivity in the presence of oxygen should be increased to increase the surface reaction rate. Methods for increasing the surface reaction rate include, for example, increasing the amount of (A) nitrogen-containing monomer, increasing the amount of (C) crosslinking component, using a crosslinking component with a high gel fraction when homopolymerized (a (meth)acrylate monomer with a high gel fraction when homopolymerized), using a large amount of (D) photopolymerization initiator, and increasing the amount of (E) thermoplastic resin (non-reactive component).

[0056] In this invention, the above UV-curable adhesive composition is coated onto a substrate to a thickness of 150 μm, and exposed to ultraviolet light with a wavelength of 315 nm to 480 nm at an irradiance of 90 mW / cm² in an atmospheric environment. 2 , irradiation amount 1350mJ / cm 2The glass transition temperature (Tg) of the cured product obtained by irradiation under these conditions is preferably 20°C to -30°C. Having a glass transition temperature within this range allows for excellent adhesion to various substrates. A glass transition temperature of 1°C or less is more preferable.

[0057] The above UV-curing adhesive composition has no limited uses, but is particularly suitable for printing. By applying it to a substrate (adhesion material) in a desired pattern through printing to form a heat-dissipating adhesive layer, the cutting process can be eliminated, which is advantageous compared to obtaining an adhesive of a desired shape by cutting a sheet-like adhesive immediately before bonding. As a result, waste generation can be reduced, and the environmental burden can be minimized. The printing method is not particularly limited and includes screen printing, inkjet printing, gravure printing, etc., with screen printing being particularly preferred.

[0058] The viscosity of the above UV-curable adhesive composition is not limited, but it is preferably a paste with a viscosity of 5 to 500 Pa·s at 25°C, as measured using an E-type viscometer. A more preferable lower limit for the viscosity is 10 Pa·s, and a more preferable upper limit is 100 Pa·s. The viscosity can be measured, for example, using a VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) as an E-type viscometer, by selecting a rotation speed of 1 to 100 rpm from the optimal torque number in each viscosity range using the CP1 cone plate.

[0059] The method for preparing the above-mentioned UV-curable adhesive composition is not particularly limited, and examples include a method of mixing (A) a nitrogen-containing monomer, (B) a monofunctional (meth)acrylate monomer, (C) a crosslinking component, (D) a photopolymerization initiator, (E) a thermoplastic resin, and additives as needed, using a mixer. Examples of such mixers include homodispers, homomixers, universal mixers, planetary mixers, kneaders, and three-roll mixers.

[0060] Furthermore, an adhesive obtained by printing the UV-curable adhesive composition of the present invention and irradiating it with ultraviolet light is also one of the present inventions. The adhesive of the present invention can be formed into a desired shape by printing such as screen printing, and has excellent adhesion to various substrates, making it applicable to a variety of uses, and may be used for bonding electronic components inside electronic devices.

[0061] The above-mentioned UV-curable adhesive composition forms an adhesive layer by curing with UV light. Its application method may involve forming the adhesive layer on a substrate (separator) to create an adhesive sheet transferable to the adherend, or it may involve forming the adhesive layer directly on the adherend. The method of forming the adhesive layer directly on the adherend minimizes the number of bonding steps and prevents air bubbles from forming at the interface during bonding. On the other hand, the method of forming the adhesive layer on a substrate (separator) has the advantage of fewer constraints on construction, as the adhesive layer is positioned on the adherend by transfer.

[0062] The following describes adhesive sheets, laminates, and methods for manufacturing laminates using the above-mentioned ultraviolet-curable adhesive composition.

[0063] An adhesive sheet comprising a base material and an adhesive layer made of the ultraviolet-curable adhesive composition of the present invention, provided on at least one side of the base material, is also one of the present inventions.

[0064] The above-mentioned substrate is not particularly limited, but a resin film is preferably used. Examples of resin film materials include polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetylcellulose and triacetylcellulose, acrylic polymers such as polymethyl methacrylate, styrene polymers such as polystyrene and acrylonitrile-styrene copolymer (AS resin), and polycarbonate polymers. In addition, examples of transparent protective film materials include polyethylene, polypropylene, polyolefin polymers having a cyclo- or norbornene structure, ethylene-propylene copolymer, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers, acrylate polymers, polyoxymethylene polymers, epoxy polymers, or mixtures thereof. The thickness of the above-mentioned substrate is not particularly limited, for example, about 1 to 500 μm.

[0065] The above-mentioned substrate is preferably treated with a release agent so that the adhesive layer can be easily peeled off after being attached to the adherend. For example, a release-treated polyethylene terephthalate (PET) sheet is preferably used.

[0066] The adhesive layer described above can be formed by applying the UV-curable adhesive composition and then curing it by UV irradiation. Preferably, the adhesive layer is partially arranged on the substrate by methods such as printing.

[0067] The thickness of the adhesive layer is preferably 30 μm or more, and more preferably 50 μm or more. A thickness of 30 μm or more of the adhesive layer ensures sufficient adhesion. While there is no particular upper limit to the thickness of the adhesive layer, from the viewpoint of miniaturizing electronic devices, it is preferably 1000 μm or less, and more preferably 500 μm or less.

[0068] The above adhesive sheet can be used to create a laminate by bonding one side of the adhesive layer (the side not in contact with the substrate) to a first adherend, then peeling off the substrate, and bonding the other side of the exposed adhesive layer to a second adherend. Examples of materials for the first and second adherends include metals such as stainless steel and aluminum, and resins. A laminate in which the first adherend and the second adherend are bonded together via the adhesive layer contained in the adhesive sheet of the present invention is also one of the present inventions.

[0069] Another method of manufacturing a laminate is also part of the present invention, which involves applying the ultraviolet-curable adhesive composition of the present invention onto a first adherend, forming an adhesive layer by exposure, and then attaching a second adherend onto the adhesive layer to produce a laminate. Suitable methods for applying the ultraviolet-curable adhesive composition include inkjet printing, screen printing, spray coating, spin coating, gravure offset printing, or reverse offset printing. Furthermore, it is preferable that the ultraviolet-curable adhesive composition is partially applied onto the first adherend. [Effects of the Invention]

[0070] According to the present invention, it is possible to provide an ultraviolet-curable adhesive composition that exhibits excellent printability, ultraviolet reactivity in the presence of oxygen, and adhesion to various substrates. Furthermore, according to the present invention, it is possible to provide an adhesive using the ultraviolet-curable adhesive composition. [Brief explanation of the drawing]

[0071] [Figure 1]This diagram illustrates the method for calculating surface reaction rates and back reaction rates, and also explains the sample preparation method and the object to be measured. [Figure 2] This diagram illustrates the method for calculating the surface reaction rate and back surface reaction rate, specifically the method for calculating the surface reaction rate and back surface reaction rate from the obtained IR spectrum. [Modes for carrying out the invention]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0073] <Examples 1-12, Comparative Examples 1-8> According to the mixing ratios listed in Tables 1 and 2, each material was mixed in a planetary agitator (Sinky Co., Ltd. "Awatori Rentaro") to obtain the ultraviolet-curing adhesive compositions of the examples and comparative examples. Details of the materials listed in the table using abbreviations are as follows: NVC: N-vinyl-ε-caprolactam (manufactured by Tokyo Chemical Industry Co., Ltd.) ACMO: Acryloylmorpholine (manufactured by KJ Chemical Co., Ltd.) DMAA: Dimethylacrylamide (manufactured by KJ Chemical Co., Ltd.) NVA: N-vinylacetamide (manufactured by Showa Denko Corporation) 150D: Tetrahydrofurfuryl alcohol acrylic acid polymer ester (manufactured by Osaka Organic Chemical Industry Co., Ltd., "Viscoat #150D") IDAA: Isodecyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 4HBA: 4-Hydroxybutyl acrylate (manufactured by Mitsubishi Chemical Corporation) CN9004: Urethane (bifunctional, manufactured by Sartomer Japan, "CN9004") EB3700: Bisphenol A type epoxy acrylate (difunctional, manufactured by Daicel Ornex, "EBECRYL 3700") DPHA: Dipentaerythritol hexaacrylate (hexafunctional, manufactured by Daicel Ornex) TPO: Omnirad TPO H (manufactured by IGM Resins BV) 819: Omnirad 819 (manufactured by IGM Resins BV) 184: Omnirad 184 (manufactured by IGM Resins BV) KS-66: An oil compound type defoaming agent containing finely powdered silica in silicone oil (manufactured by Shin-Etsu Silicone Co., Ltd., "KS-66"). BYK-052: Polymer-type silicone-free defoaming agent (manufactured by Bic Chemie Japan, "BYK-052 N")

[0074] The acrylic polymer used as the thermoplastic resin in the examples and comparative examples was prepared by the following method. In a 2 L separable flask equipped with a thermometer, stirrer, nitrogen inlet tube, and condenser, 100 parts by weight of 2-ethylhexyl acrylate, 3 parts by weight of acrylic acid, 0.1 parts by weight of 2-hydroxyethyl acrylate, and 300 parts by weight of ethyl acetate as the polymerization solvent were added. Next, nitrogen gas was blown into the reaction vessel for 30 minutes to purge it with nitrogen, and then the reaction vessel was heated to 80°C while stirring. After 30 minutes, 0.5 parts by weight of t-butylperoxy-2-ethylhexanoate (1-hour half-life temperature: 92.1°C, 10-hour half-life temperature: 72.1°C) as a polymerization initiator was diluted with 5 parts by weight of ethyl acetate, and the resulting polymerization initiator solution was added dropwise to the reaction vessel over 6 hours. After that, the reaction was continued at 80°C for another 6 hours, and then the reaction mixture was cooled to obtain an acrylic polymer solution. The obtained solution was diluted with a diluent (a mixed solvent of methanol and toluene, with a weight ratio of methanol to toluene of 1:2) to obtain a solution with a solid content of 20% by weight. Next, this solution was applied using a coater onto a release-treated PET film to a thickness of 100 μm after drying, and dried at 80°C for 1 hour and then at 110°C for 1 hour to obtain an acrylic polymer.

[0075] <Rating> The ultraviolet-curable adhesive compositions of Examples 1-12 and Comparative Examples 1-8, as well as the cured products thereof, were evaluated as follows. The results are shown in Tables 1 and 2.

[0076] The cured material used for evaluation was prepared as follows. (Preparation of hardened material) A UV-curable adhesive composition was applied to a PET sheet (Nipper Co., Ltd. "1-E", 50 μm thick) with one side release treatment using an applicator to a thickness of 150 μm. Then, without sealing the coated surface, it was cured in an atmospheric environment using a batch-type UV LED curing device (Itec Co., Ltd. "M UVBA") with a wavelength of 365 nm and an irradiance of 30 mW / cm². 2 UV irradiance of 60 mW / cm² at a wavelength of 405 nm 2 Set the parameters to be such that the irradiation energy is 1350 mJ / cm². 2 By irradiating the UV-curable adhesive composition with ultraviolet light, a cured product was obtained.

[0077] (Surface reaction rate and back reaction rate) Figures 1 and 2 illustrate the methods for calculating the surface reaction rate and back surface reaction rate. Figure 1 explains the sample preparation method and the object to be measured, while Figure 2 explains the method for calculating the surface reaction rate and back surface reaction rate from the obtained IR spectrum. The cured sample prepared as described above (cured in an atmospheric environment without sealing the coated surface; see Figure 1(a)) was designated as "Cured Product A," and the sample prepared by irradiating with ultraviolet (UV) light in the same manner as Cured Product A, except that the UV-curable adhesive composition 10 was sandwiched between PET sheets 20 (see Figure 1(b)), was designated as "Cured Product B." First, approximately 0.3 g of cured material A was placed on an aluminum pan, and a mixed solvent containing THF:acetone:ethanol in a weight ratio of 8:1:1 was gently added to prevent the cured material sample from splashing. The sample was allowed to swell for about 2 hours. After that, it was dried at 110°C for 30 minutes, 170°C for 1 hour, and 190°C for 30 minutes. It was confirmed that the mixed solvent had completely evaporated after drying. The weights of the dried aluminum pan and the dried sample were then weighed, and the overall reaction rate was calculated using the following formula. Overall reaction rate [%] = 100 - (Total weight of aluminum pan and sample after drying - Weight of aluminum pan before drying) / (Total weight of aluminum pan and sample before drying - Weight of aluminum pan before drying) × 100

[0078] Next, the IR spectra shown in Figure 2 were measured on the front and back surfaces of the cured material A using the ATR method with a Fourier transform infrared spectrometer (Nicolet iS5 FT-IR), and the IR spectrum was measured at 810 cm⁻¹. -1 The absorbance values ​​were obtained. The obtained values ​​were designated as "absorbance without PET (front surface)" and "absorbance without PET (back surface)," respectively. Furthermore, regarding the irradiated surface (surface) of cured material B during curing, after peeling off the PET sheet, the IR spectrum shown in Figure 2 was measured similarly using the ATR method, and the 810 cm⁻¹ spectrum was measured. -1 The absorbance value was obtained. The obtained value was defined as "Absorbance with PET (Surface)". From these values, the surface reaction rate and the back surface reaction rate were calculated using the following formula. Surface reaction rate [%] = Absorbance without PET (surface) / Absorbance with PET (surface) Backside reaction rate [%] = Absorbance without PET (backside) / Absorbance with PET (front) Here, "absorbance without PET (front) / absorbance with PET (front)" and "absorbance without PET (back) / absorbance with PET (front)" are obtained by measuring the UV-curable adhesive composition before curing at 810 cm². -1 This refers to the magnitude of the absorbance without PET (front) and the absorbance without PET (back) when the absorbance of the surface is set to 0% (minimum value) and the absorbance with PET is set to 100% (maximum value). For example, "absorbance without PET (front) / absorbance with PET (front)" represents the reaction rate X in Figure 2 and is expressed by the following formula. Response rate X = B / A × 100 A = |ABS.M - ABS.0| B = |ABS.D - ABS.0|

[0079] (Tg) The cured material prepared as described above was measured using a dynamic viscoelasticity measuring device (IT Measurement Control Co., Ltd. "DVA-200") under the following conditions, and the tanδ peak temperature was defined as Tg. [Measurement conditions] Shear method Measurement temperature: -100~200℃ Heating rate: 3°C / min Distortion level: 0.8% Frequency: 1Hz

[0080] (Screen printability) The screen printability of UV-curing adhesive compositions was evaluated using a screen printing machine ("SSA-PC560E," manufactured by SERIA). Using a patterned 70-mesh printing plate, the UV-curing adhesive composition was pattern-coated onto a PET sheet (Nippa Corporation's "1-E," 50 μm thick) in a 22 mm square shape with a thickness of 100 μm and a width of 1 mm. The condition of the coating film was then observed. The evaluation was performed according to the following criteria. [bubbles] ○: No air bubbles were found in the paint film. ×: Bubbles were present in the paint film. [film thickness] ○: No dripping occurred, and the paint film did not extend beyond the pattern. ×: The paint film extended beyond the pattern.

[0081] (viscosity) A VISCOMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) was used as the E-type viscometer. A 0.4 mL sample was collected using the CP1 cone plate at a rotation speed of 10 rpm and measured. Only Comparative Example 5 was measured at 100 rpm.

[0082] (Adhesion strength at room temperature and high temperature: Peel test) A UV-curable adhesive composition was applied to the inner surface of an easy-to-adhere polyester film ("Cosmoshine A4100," manufactured by Toyobo Co., Ltd.) to a thickness of 150 μm using an applicator. Then, without sealing the coated surface, the film was cured in an atmospheric environment using a batch-type UV LED curing device ("M UVBA," manufactured by ITEC Corporation) with a UV irradiance of 30 mW / cm² at a wavelength of 365 nm.2 UV irradiance of 60 mW / cm² at a wavelength of 405 nm 2 Set the parameters to be such that the irradiation energy is 1350 mJ / cm². 2 The UV-curable adhesive composition was cured by irradiation with ultraviolet light to obtain a cured product. Five test pieces were prepared by sealing the air surface with a PET sheet (Nipper Co., Ltd. "1-E", 50 μm thick) with one side release treatment, and cutting them to a width of 25 mm and a length of 200 mm (adhesion surface 125 mm). Next, the sealed PET sheet with one side release treatment was peeled off, the adherend was attached to the exposed surface, and pressure was applied by passing a 2 kg roller back and forth once. The pressed test pieces were peeled 180° at a speed of 300 mm / min using a universal testing machine (A AND D Co., Ltd. "Tensilon RTI-1310"). The room temperature adhesive strength was measured using test pieces adjusted to 25°C, and high-temperature evaluation at 60°C was performed in a chamber using a constant temperature bath (Mita Sangyo Co., Ltd.). For four types of substrates—glass, ABS, Cu, and Al—the adhesive strength at room temperature and at high temperature were measured and evaluated according to the following criteria. [Adhesion at room temperature] ◎:20N / inch or more ○: 10 N / inch or more, less than 20 N / inch △: 5N / inch or more, less than 10N / inch ×: Less than 5N / inch [High temperature adhesive strength] 〇:5N / inch or more ×: Less than 5N / inch

[0083] [Table 1]

[0084] [Table 2] [Industrial applicability]

[0085] According to the present invention, it is possible to provide an ultraviolet-curable adhesive composition that exhibits excellent printability, ultraviolet reactivity in the presence of oxygen, and adhesion to various substrates. Furthermore, according to the present invention, it is possible to provide an adhesive using the ultraviolet-curable adhesive composition. [Explanation of symbols]

[0086] 10: UV-curing adhesive composition 20: PET sheet

Claims

1. (A) Nitrogen-containing monomers and (B) Monofunctional (meth)acrylate monomers, (C) Crosslinking component, (D) Photopolymerization initiator, (E) A thermoplastic resin that does not react with the nitrogen-containing monomer (A) and the monofunctional (meth)acrylate monomer (B), an ultraviolet-curable adhesive composition, The content of the nitrogen-containing monomer (A) is 10 to 35% by weight relative to 100% by weight of the UV-curable adhesive composition. The content of the (B) monofunctional (meth)acrylate monomer in 100 parts by mass of the UV-curable adhesive composition is 20 to 70 parts by weight. The content of the crosslinking component (C) is 0.1 to 25% by weight in 100% by weight of the total amount of the nitrogen-containing monomer (A), the monofunctional (meth)acrylate monomer (B), and the crosslinking component (C). The content of (E) thermoplastic resin is 0.1 to 140 parts by weight per 100 parts by weight of the total amount of (A) nitrogen-containing monomer and (B) monofunctional (meth)acrylate monomer. The viscosity measured using an E-type viscometer at 25°C and 10 rpm is 5 to 500 Pa·s. The composition is coated onto a substrate to a thickness of 150 μm, and exposed to ultraviolet light with a wavelength of 315 nm to 480 nm in an atmospheric environment at an irradiance of 90 mW / cm². ２ , irradiation amount 1350mJ / cm ２ The reaction rate of the air-facing side and the substrate-facing side of the cured product obtained by irradiation under these conditions is 80% or higher. Used in screen printing A UV-curable adhesive composition characterized by the following features.

2. The ultraviolet-curable adhesive composition according to claim 1, wherein the nitrogen-containing monomer (A) comprises a cyclic amide compound having a vinyl group and a lactam structure.

3. Furthermore, the UV-curable adhesive composition according to claim 1 contains an antifoaming agent.

4. The ultraviolet-curable adhesive composition according to claim 1, wherein the glass transition temperature of the cured product is 20°C to -30°C.

5. An adhesive characterized by being obtained by printing the ultraviolet-curable adhesive composition according to claim 1, 2, 3, or 4 and irradiating it with ultraviolet light.

6. An adhesive sheet comprising a base material and an adhesive layer provided on at least one side of the base material, the adhesive layer being made of the ultraviolet-curable adhesive composition according to claim 1, 2, 3, or 4.

7. The adhesive sheet according to claim 6, wherein the adhesive layer is partially disposed on the substrate.

8. A laminate characterized in that a first adherend and a second adherend are bonded together via the adhesive layer contained in the adhesive sheet according to claim 6.

9. A method for manufacturing a laminate, characterized by screen printing the ultraviolet-curable adhesive composition according to claim 1, 2, 3, or 4 onto a first adherend, exposing it to light to form an adhesive layer, and then attaching a second adherend onto the adhesive layer to produce a laminate.

10. The method for manufacturing a laminate according to claim 9, wherein the ultraviolet-curable adhesive composition is partially applied to the first adherend.

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