Active energy ray-curable adhesive composition, cured product, and laminate

Abstract

[Problem] The present invention provides an active energy ray-curable adhesive composition which provides a cured product layer having high adhesive strength at an initial stage and after exposure to high temperatures, and excellent resistance to thermal yellowing and resistance to wet heat whitening. [Technical means] An active energy ray-curable adhesive composition comprising specific amounts of: a urethane (meth) acrylate (A) having a weight-average molecular weight of 50,000-200,000; the urethane (meth) acrylate (A) is a reaction product of a chain polyether polyol (a1) having an alkylene chain having 4 or more carbon atoms as a repeating unit, a polyisocyanate (a2) and a mono (meth) acrylate (a3-1) having a hydroxyl group or a mono (meth) acrylate (a3-2) having an isocyanate group, and a mono (meth) acrylate (B) not having a hydroxyl group. And a mono (meth) acrylate (C) having a hydroxyl group.

Description

Technical Field

[0001] The present invention relates to an active energy ray-curable adhesive composition, a cured product, and a laminate. Background Art

[0002] Adhesives are used in mobile devices such as smartphones and tablets, digital home appliances such as digital cameras, stereos and TVs, wireless devices, and communication devices such as modems. They are also used in automotive touch panels for car navigation systems, audio displays, and rear-seat entertainment systems.

[0003] Adhesives used in automotive touch panels are required not only to have strong adhesion but also to not turn yellow even when exposed to high temperatures (high heat yellowing resistance), maintain high adhesion, and not whiten even under high temperature and high humidity (high moisture-heat whitening resistance).

[0004] To address these issues, the present applicant has also disclosed a UV-curable adhesive comprising a polyether polyurethane (meth)acrylate, a mono(meth)acrylate alkyl ester having an alkyl group with 4 to 12 carbon atoms, a mono(meth)acrylate cycloalkyl ester having a cycloalkyl group with 6 to 10 carbon atoms, and a mono(meth)acrylate containing a primary hydroxyl group, combined with a specific photopolymerization initiator and an antioxidant (Patent Document 1). However, these required properties have not yet been achieved, and there is still room for improvement. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-100403 Summary of the Invention Technical problem to be solved by the invention

[0006] The technical problem of the present invention is to provide an active energy ray-curable adhesive composition that provides a cured product layer having high initial adhesive strength and after exposure to high temperatures, and excellent resistance to heat yellowing and resistance to wet heat whitening. Technical means to solve technical problems

[0007] The present inventors have conducted intensive research and have found that they have solved the above-mentioned technical problems. Specifically, the present invention relates to the following active energy ray-curable adhesive composition, cured product, and laminate.

[0008] 1. An active energy ray-curable adhesive composition comprising: A polyurethane (meth)acrylate (A) having a weight-average molecular weight of 50,000 to 200,000, wherein the polyurethane (meth)acrylate (A) is a reaction product of a chain polyether polyol (a1), a polyisocyanate (a2), and a mono(meth)acrylate (a3-1) having a hydroxyl group or a mono(meth)acrylate (a3-2) having an isocyanate group, wherein the chain polyether polyol (a1) has an alkylene chain having 4 or more carbon atoms as a repeating unit. a mono(meth)acrylate (B) having no hydroxyl group, and a mono(meth)acrylate (C) having a hydroxyl group; Component (B) is an alkyl mono(meth)acrylate (B1) having an alkyl group having 6 to 20 carbon atoms, and a cycloalkyl mono(meth)acrylate (B2). The ratio of the mass of the non-volatile components of the component (B1) to the component (B2) [(B1) / (B2)] is 0.05 or more and less than 1, When the total of the components (A), (B), and (C) is 100% by mass, the content of the component (C) is 10% by mass to 35% by mass.

[0009] 2. The active energy ray-curable adhesive composition according to the above item 1, further comprising a tackifier resin (D).

[0010] 3. A cured product of the active energy ray-curable adhesive composition according to 1 or 2 above.

[0011] 4. A laminate comprising the cured product according to 3 above on at least one surface of a substrate. Beneficial effects

[0012] The active energy ray-curable adhesive composition of the present invention (hereinafter referred to as "adhesive composition") provides a cured product layer (hereinafter also referred to as "cured product layer") having high initial adhesive strength and after exposure to high temperatures, and excellent resistance to heat yellowing and resistance to wet heat whitening. DETAILED DESCRIPTION

[0013] The adhesive composition of the present invention comprises a specific urethane (meth)acrylate (A) (hereinafter referred to as component (A)), a mono(meth)acrylate (B) having no hydroxyl group (hereinafter referred to as component (B)), and a mono(meth)acrylate (C) having a hydroxyl group (hereinafter referred to as component (C)).

[0014] The component (A) of the present invention is a reaction product of a chain polyether polyol (a1) (hereinafter referred to as component (a1)), a polyisocyanate (a2) (hereinafter referred to as component (a2)), and a mono(meth)acrylate (a3-1) having a hydroxyl group (hereinafter referred to as component (a3-1)) or a mono(meth)acrylate (a3-2) having an isocyanate group (hereinafter referred to as component (a3-2)). The chain polyether polyol (a1) has an alkylene chain having 4 or more carbon atoms as a repeating unit.

[0015] Component (a1) is a chain polyether polyol having an alkylene chain with 4 or more carbon atoms as a repeating unit. The structure having an alkylene chain with 4 or more carbon atoms as a repeating unit refers to the structure represented by general formula (1). When component (a1) is used, the resulting component (A) tends to have a weight-average molecular weight described below, and the cured layer containing component (A) tends to exhibit excellent resistance to heat yellowing.

[0016] [Chemical 1] HO-[(CH2) m O] n -H···(1) (In formula (1), m represents an integer greater than or equal to 4, and n represents an integer greater than or equal to 2.)

[0017] As the component (a1), polytetramethylene glycol is preferred because the cured product layer readily exhibits excellent resistance to thermal yellowing.

[0018] Examples of commercially available products of the component (a1) include "PTMG650," "PTMG850," "PTMG1000," "PTMG1300," "PTMG1500," "PTMG1800," "PTMG2000," "PTMG3000," "PTMG3200," "BioPTMG650," "BioPTMG1000," "BioPTMG2000," and "BioPTMG3000" (all manufactured by Mitsubishi Chemical Corporation). These may be used alone or in combination of two or more.

[0019] In addition, a polyol (a1') other than component (a1) (hereinafter referred to as component (a1')) may be used in combination. Examples of component (a1') include chain polyether polyols having an alkylene chain with 3 or fewer carbon atoms, such as polyethylene glycol and polypropylene glycol; polyester polyols, poly(meth)acrylic acid polyols, polyolefin polyols, polycaprolactone polyols, and polycarbonate polyols. These may be used alone or in combination of two or more. Furthermore, (meth)acrylic acid refers to acrylic acid or methacrylic acid.

[0020] The amount of the component (a1′) used is preferably 30% by mass or less, more preferably 20% by mass or less, based on 100% by mass of the total of the components (a1) and (a1′).

[0021] The physical properties of the component (a1) are, for example, preferably a number average molecular weight (polystyrene conversion value by gel permeation chromatography (GPC)) of 1,000 to 3,000, and more preferably 2,000 to 3,000, from the viewpoint of adhesive strength.

[0022] As the component (a2), for example, there can be mentioned: Aromatic diisocyanates such as toluene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; Aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate; Alicyclic diisocyanates such as dicyclohexylmethane diisocyanate, isophorone diisocyanate, 1,4-cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, etc. can be used alone or in combination of two or more. In addition, as (a2) component, urate ester form, adduct form or biuret form of these can also be used.

[0023] Among them, aliphatic diisocyanates and alicyclic diisocyanates are preferred, and hexamethylene diisocyanate and isophorone diisocyanate are more preferred, because the cured layer readily exhibits high adhesive strength even after exposure to high temperatures.

[0024] Examples of the component (a3-1) include mono(meth)acrylates having a hydroxyl group, such as 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 5-hydroxypentyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate, 7-hydroxyheptyl(meth)acrylate, and 8-hydroxyoctyl(meth)acrylate. These may be used alone or in combination of two or more.

[0025] Examples of the component (a3-2) include 2-isocyanatoethyl (meth)acrylate, 1,1-bis(acryloyloxymethyl)ethyl isocyanate, and 2-(o-[1'-methylpropyleneamino]carboxyamino)ethyl methacrylate (2-(o-[1'-methylpropylideneamino]carboxyamino)ethyl methacrylate). These may be used alone or in combination of two or more.

[0026] Among them, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-isocyanatoethyl (meth)acrylate are preferred because they readily react with the functional groups (hydroxyl groups derived from component (a1) or isocyanate groups derived from component (a2)) of the urethane prepolymer formed by the reaction of components (a1) and (a2). Furthermore, the term "(meth)acrylate" refers to either acrylate or methacrylate.

[0027] Component (A) can be produced by various known methods. Hereinafter, component (A1) obtained by using component (a3-1) as component (a3) ​​(hereinafter referred to as component (A1)) and component (A2) obtained by using component (a3-2) as component (a3) ​​(hereinafter referred to as component (A2)) will be described separately.

[0028] Component (A1) is obtained by, for example, reacting component (a1) with component (a2) to produce an isocyanate-terminated urethane prepolymer (hereinafter referred to as component (A1')), and then reacting component (A1') with component (a3-1). As reaction conditions, the preferred reaction temperature is 70 to 85°C and the reaction time is 1 to 5 hours. In addition, regarding the ratio of component (a1) to component (a2), the number of moles of isocyanate groups (NCO (a2) ) and the molar number of hydroxyl groups of component (a1) (OH (a1) ) ratio (NCO (a2) / OH (a1) ) is preferably 1.01 to 2. In addition, as the usage ratio of the component (A1') to the component (a3-1), the number of moles of the isocyanate group (NCO (A1’) The number of moles of hydroxyl groups (OH (a3-1) ) ratio (NCO (A1’) / OH (a3-1) ) is preferably 0.25 to 1.

[0029] Regarding component (A2), after reacting component (a1) with component (a2) to obtain a hydroxyl-terminated urethane prepolymer (hereinafter referred to as component (A2')), component (A2') may be reacted with component (a3-2). The reaction temperature and reaction time are the same as those for component (A1). In addition, as the ratio of component (a1) to component (a2), it is preferred that (NCO (a2) / OH (a1) ) is 0.50 to 0.99. In addition, as the usage ratio of the component (A2') to the component (a3-2), the molar number of the isocyanate group (NCO (a3-2) ) and the number of moles of hydroxyl groups (OH (A2’) Ratio (NCO (a3-2) / OH(A2’) It is preferably 0.5 to 1.

[0030] The production of these components (A1) and (A2) can be carried out in the presence of an organic solvent described below, but is preferably carried out in the absence of a solvent to reduce environmental load. In addition, their production can also be carried out in the presence of component (B1) described below.

[0031] The weight average molecular weight of the obtained (A) component is 50,000 to 200,000. If the weight average molecular weight is less than 50,000, the adhesive force of the cured layer after exposure to high temperature is easily reduced, and the resistance to moist heat whitening is also easily deteriorated. On the other hand, if it exceeds 200,000, the viscosity becomes high, and it is difficult to prepare the adhesive composition, or the chain length of the (A) component becomes long, causing the adhesive composition to be difficult to solidify, and the initial adhesive force of the obtained cured layer is easily reduced. In addition, from the same aspect, the weight average molecular weight of the (A) component is preferably 50,000 to 150,000, and more preferably 60,000 to 100,000. In addition, the weight average molecular weight is a value measured by gel permeation chromatography (GPC method) using polystyrene as a standard substance.

[0032] The content of component (A) when the total of component (A), component (B) and component (C) is taken as 100% by mass is preferably 10% by mass to 50% by mass, more preferably 15% by mass to 40% by mass, and even more preferably 20% by mass to 40% by mass, in terms of the non-volatile content mass (the same below), from the viewpoint that the cured layer has high adhesive strength in the initial stage and after exposure to high temperatures and is also likely to have excellent heat yellowing resistance.

[0033] The component (B) is a mono(meth)acrylate having no hydroxyl group, and is used to ensure that the cured layer exhibits high adhesive strength both initially and after exposure to high temperatures.

[0034] The content of the component (B) when the total of the components (A), (B) and (C) is 100% by mass is preferably 20% to 80% by mass, more preferably 30% to 70% by mass, and even more preferably 40% to 60% by mass, from the viewpoint that the cured layer readily exhibits high adhesive strength both initially and after exposure to high temperatures.

[0035] The adhesive composition of the present invention essentially contains, as component (B), an alkyl mono(meth)acrylate (B1) having an alkyl group having 6 to 20 carbon atoms (hereinafter referred to as component (B1)) and a cycloalkyl mono(meth)acrylate (B2) (hereinafter referred to as component (B2)).

[0036] Component (B1) includes n-hexyl (meth)acrylate, isohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, tridecyl (meth)acrylate, lauryl (meth)acrylate (n-dodecyl (meth)acrylate), myristyl (meth)acrylate (n-tetradecyl (meth)acrylate), palmityl (meth)acrylate (n-hexadecyl (meth)acrylate), stearyl (meth)acrylate (n-octadecyl (meth)acrylate), and isostearyl (meth)acrylate. These may be used alone or in combination of two or more.

[0037] Among them, from the perspective that the cured layer readily exhibits high adhesive strength both initially and after exposure to high temperatures, preferred are alkyl mono(meth)acrylates having an alkyl group with 7 to 15 carbon atoms, and more preferred are 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, and isostearyl (meth)acrylate.

[0038] Examples of the component (B2) include monocyclic (meth)acrylates such as cyclopentyl (meth)acrylate and cyclohexyl (meth)acrylate; Dicyclic (meth)acrylates such as norbornyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentanyloxyethyl (meth)acrylate; Tricyclic (meth)acrylates such as tricyclodecane dihydroxymethyl di(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0039] Among them, dicyclic (meth)acrylates are preferred, and isobornyl (meth)acrylate and dicyclopentanyl (meth)acrylate are more preferred, because the cured layer tends to exhibit high adhesive strength even after exposure to high temperatures and also tends to have excellent resistance to thermal yellowing.

[0040] The ratio of the mass of the non-volatile components of component (B1) to component (B2) [(B1) / (B2)] is 0.05 or more and less than 1. If this ratio is less than 0.05, the adhesive composition will have a reduced viscosity when cured, making it difficult to exert adhesive strength, and the resistance to whitening due to moist heat will also tend to deteriorate. If it is 1 or more, the adhesive strength of the cured layer after exposure to high temperatures will tend to decrease. From the same perspective, the above ratio is preferably 0.1 or more and 0.8 or less, and more preferably 0.2 or more and 0.6 or less.

[0041] The adhesive composition of the present invention may contain a mono(meth)acrylate (B') not having a hydroxyl group (hereinafter referred to as component (B')) in addition to the components (B1) and (B2).

[0042] Examples of the component (B') include mono(meth)acrylates having an alkyl group having 5 or less carbon atoms, such as methyl(meth)acrylate, ethyl(meth)acrylate, n-propyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, sec-butyl(meth)acrylate, tert-butyl(meth)acrylate, and n-pentyl(meth)acrylate. Aromatic mono(meth)acrylates such as phenyl(meth)acrylate, benzyl acrylate, 2-phenylethyl(meth)acrylate, and nonylphenoxypolyethylene glycol(meth)acrylate may be used alone or in combination of two or more.

[0043] The content of the component (B') is preferably 30% by mass or less, more preferably 10% by mass or less, based on 100% by mass of the total of the components (A), (B), and (C).

[0044] The component (C) is a mono(meth)acrylate having a hydroxyl group, and is a component for allowing the cured product layer to exhibit excellent resistance to whitening due to moisture and heat.

[0045] Examples of the component (C) include aliphatic mono(meth)acrylates having one primary hydroxyl group, such as 2-hydroxyethyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, 5-hydroxypentyl(meth)acrylate, 6-hydroxyhexyl(meth)acrylate, 7-hydroxyheptyl(meth)acrylate, and 8-hydroxyoctyl(meth)acrylate. Aliphatic mono(meth)acrylates having one secondary hydroxyl group, such as 2-hydroxypropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl(meth)acrylate, 4-hydroxyhexyl(meth)acrylate, and 5-hydroxyhexyl(meth)acrylate; Aliphatic mono(meth)acrylates having two hydroxyl groups, such as 2,3-dihydroxypropyl(meth)acrylate, 3,4-dihydroxybutyl(meth)acrylate, glycerol mono(meth)acrylate, and 1,4-dihydroxyheptyl(meth)acrylate; Alicyclic mono(meth)acrylates having one hydroxyl group, such as 4-hydroxycyclohexyl(meth)acrylate and 3-hydroxy-1-adamantyl(meth)acrylate; Alicyclic mono(meth)acrylates having two hydroxyl groups, such as 1,4-cyclohexanedimethanol mono(meth)acrylate and 3,5-dihydroxyadamantyl(meth)acrylate; Aromatic (meth)acrylates having one hydroxyl group, such as 2-hydroxy-3-phenoxypropyl (meth)acrylate, etc. These may be used alone or in combination of two or more.

[0046] Among them, (meth)acrylates having one primary hydroxyl group are preferred, and 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferred, because the cured layer readily exhibits excellent resistance to whitening due to moisture and heat.

[0047] As the content of the (C) component when the total of (A) component, (B) component and (C) component is set to 100 mass %, it is 10 mass % to 35 mass %. If the content of (C) component is less than 10 mass %, the initial adhesive force and the resistance to moist heat whitening of the cured product layer are easily deteriorated, and if it exceeds 35 mass %, the adhesive force of the cured product layer in the initial stage and after exposure at high temperature is easily reduced. In addition, from the same aspect, the content of (C) component is preferably 15 mass % to 30 mass %, more preferably 15 mass % to 25 mass %.

[0048] The adhesive composition of the present invention may contain a tackifier resin (D) (hereinafter referred to as component (D)) from the viewpoint that the cured layer readily exhibits high adhesive strength both initially and after exposure to high temperatures.

[0049] Examples of the component (D) include rosin-based resins, aliphatic petroleum resins, aromatic petroleum resins, phenolic resins, styrene resins, xylene resins, coumarone-indene resins, terpene-based resins, terpene-phenolic resins, aromatic modified terpene resins, and hydrogenated products of these resins. These may be used alone or in combination of two or more.

[0050] Examples of commercially available products of the component (D) include "Pensel D-135", "SuperEster A-125", "Pinecrystal KE-100", "Pinecrystal KE-311", "Pinecrystal KE-604", "Arkon P-100", "Arkon M-100", "Arkon M-135", "Arkon P-140" (manufactured by Arakawa Chemical Industries, Ltd.), "YS Polyster K125", "YS Polyster N125", "YS Polyster TH130", "YS Polyster G150", and "YS Polyster T-160" (manufactured by YASUHARA CHEMICAL Co., Ltd.), "FTR0100", "FTR0120", "FTR2085", "FTR2120", "FTR2140", "FTR6100", "FTR6110", "FTR6125" (the above are made by Mitsui Chemicals Co., Ltd.), etc.

[0051] The content of the component (D) relative to 100% by mass of the total of the components (A), (B) and (C) is preferably 10% by mass or less, and more preferably 5% by mass or less, from the perspectives that the cured layer exhibits high adhesive strength both initially and after exposure to high temperatures and also tends to have excellent resistance to whitening due to moisture and heat.

[0052] The adhesive composition of the present invention may further contain a multifunctional monomer. For example, hexanediol di(methyl)acrylate, polyethylene glycol di(methyl)acrylate, polypropylene glycol di(methyl)acrylate, neopentyl glycol di(methyl)acrylate, trimethylolpropane tri(methyl)acrylate, pentaerythritol di(methyl)acrylate, pentaerythritol tri(methyl)acrylate, pentaerythritol tetra(methyl)acrylate, dipentaerythritol di(methyl)acrylate, dipentaerythritol tri(methyl)acrylate, dipentaerythritol tetra(methyl)acrylate, dipentaerythritol penta(methyl)acrylate, dipentaerythritol hexa(methyl)acrylate, epoxy (methyl)acrylate, polyester (methyl)acrylate, carbamate (methyl)acrylate and the like (methyl)acrylate etc. can be enumerated.They can be used alone or in combination with more than two kinds.In addition, as the content of above-mentioned multifunctional monomer, relative to 100 mass parts of adhesive composition of the present invention, it is preferably below 10 mass parts, more preferably below 5 mass parts.

[0053] The adhesive composition of the present invention may also contain various known additives as needed. The additives are not particularly limited, and examples thereof include surface conditioners, surfactants, ultraviolet absorbers, antioxidants, light stabilizers, inorganic fillers, silane coupling agents, colloidal silica, defoamers, wetting agents, and rust inhibitors. These may be used alone or in combination of two or more.

[0054] The adhesive composition of the present invention is obtained by mixing components (A), (B), (C), (B'), (D), the aforementioned polyfunctional monomers, and additives. The mixing method and mixing order are not particularly limited. Furthermore, when component (A) is diluted with component (B), component (C), (B'), (D), the aforementioned polyfunctional monomers, and additives may be mixed with the resulting solution.

[0055] The adhesive composition of the present invention is substantially solvent-free, but may contain an organic solvent in an amount of less than 1% by mass, preferably less than 0.1% by mass. Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, ethylbenzene, n-propylbenzene, tert-butylbenzene, o-xylene, m-xylene, p-xylene, tetralin, decalin, and aromatic naphtha; aliphatic hydrocarbons such as n-hexane, n-heptane, n-octane, isooctane, and n-decane; alicyclic hydrocarbons such as cyclohexane; ethyl acetate, n-butyl acetate, n-pentyl acetate, 2-hydroxyethyl ... Esters such as 3-methoxybutyl acetate, 3-methoxybutyl acetate, and methyl benzoate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, isophorone, cyclohexanone, and methylcyclohexanone; glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and tert-butanol.

[0056] The adhesive composition of the present invention is blended with a photopolymerization initiator when irradiated with active energy rays.

[0057] Examples of the photopolymerization initiator include: Hydroxyketones such as 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one), 2-hydroxy-1-[4-{4-(2-hydroxy-2-methylpropionyl)benzyl}phenyl]-2-methylpropane-1-one, and 2-isopropoxy-2-phenylacetophenone; Acylphosphine oxides such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide; Oxime esters such as 1,2-octanedione 1-[4-(phenylthio)-2-(o-benzoyl oxime)] and ethyl ketone 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-1-(o-acetyl oxime); Aminoketones such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropiophenone, 2-benzyl-2-(dimethylamino)-4'-morpholinobutyrophenone, and 2-(dimethylamino)-2-(4-methylbenzyl)-1-(4-morpholin-4-ylphenyl)butan-1-one; Double (η 5 Cationic photopolymerization initiators such as 2,4-cyclopentadien-1-yl)-bis{2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl}titanium, 4-isobutylphenyl(4-methylphenyl)iodonium hexafluorophosphate, sulfonium hexafluorophosphate, and sulfonium tetrakis(pentafluorophenyl)borate; Benzil ketals such as 2,2-dimethoxy-2-phenylacetophenone (2,2-dimethoxy-1,2-diphenylethane-1-one); Benzophenones such as benzophenone, 4-methylbenzophenone, benzophenone 2-carboxylic acid methyl ester (2-benzoylbenzoic acid methyl ester), and 4,4-bis(dimethylamino)benzophenone; Thioxanthones such as 2,4-diethylthioxanthone and 2-isopropylthioxanthone; Oxyacetic acid esters such as 2-(2-oxo-2-phenylacetoxyethoxy)ethyl oxyphenylacetate and 2-(2-hydroxyethoxy)ethyl oxyphenylacetate; and methyl benzoylformate (methyl oxyphenylacetate, 1-methoxy-2-phenyl-1,2-ethanedione, methyl phenylglyoxylate). These may be used alone or in combination of two or more.

[0058] The content of the photopolymerization initiator relative to 100% by mass of the total of the components (A), (B), and (C) is preferably from 0.05% by mass to 10% by mass, more preferably from 0.2% by mass to 5% by mass.

[0059] The cured product of the present invention is a cured product obtained by curing the above-mentioned adhesive composition.

[0060] The cured product of the present invention is obtained by applying the above-mentioned adhesive composition to a substrate and then irradiating the substrate with active energy rays. Alternatively, the substrate may be dried under heating before being irradiated with active energy rays.

[0061] Examples of the substrate include plastics and paper.

[0062] Examples of the plastic include olefin resins such as polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, and cycloolefin; Polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene terephthalate (PBT), polybutylene adipate terephthalate (PBAT), polylactic acid, polyhydroxyalkanoic acid, and polycaprolactone; (Meth)acrylic resins such as polymethyl (meth)acrylate; Vinyl resins such as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and poly(ethylene vinyl acetate); Styrene resins such as polystyrene, poly(styrene-acrylonitrile) (AS resin), and poly(styrene-butadiene-acrylonitrile) (ABS resin); Polycarbonate, polyetheretherketone, polyamide, polyimide, epoxy resin, melamine resin, diacetyl cellulose, triacetyl cellulose, fluororesin, etc.

[0063] Examples of paper include bleached kraft paper, unbleached kraft paper, premium paper, medium-quality paper, lightly coated paper, coated paper, processed base paper, cardboard, white board, interleaving paper, semi-glassine, glassine, sulphate paper, and top-coated paper.

[0064] Other substrates that can be used include, for example, fabrics such as woven fabrics and non-woven fabrics; foam sheets such as polyurethane foam and chloroprene foam; rubbers such as natural rubber and butyl rubber; metals such as aluminum and copper; glass, and ITO.

[0065] Furthermore, as the substrate, a crosslinked film or a laminated film thereof may be used, and any of an untreated substrate, a substrate lightly to heavily peeled, and a substrate having an easy-adhesion layer or an anchor layer may be used.

[0066] Examples of coating methods include applicators, bar coaters, Mayer bar coaters, roll coaters, die coaters, comma coaters, knife coaters, gravure coaters, reverse gravure coaters, offset printing, flexographic printing, and screen printing. The active energy ray-curable adhesive composition is applied in an amount such that the thickness of the cured product layer is preferably 25 μm to 1000 μm, more preferably 100 μm to 500 μm.

[0067] Examples of active energy rays include ultraviolet rays, infrared rays, visible rays, electron beams, X-rays, α rays, β rays, γ rays, and neutron rays. In the present invention, light rays are preferred, and ultraviolet rays are more preferred.

[0068] As the light source of ultraviolet rays, for example, xenon lamps, high pressure mercury lamps, metal halide lamps, UV-LEDs, etc. are mentioned. In addition, the irradiation intensity of ultraviolet rays is usually 80 mW / cm 2~160mW / cm 2 , the cumulative light intensity is usually 100mJ / cm 2 ~3000mJ / cm 2 The conveying speed is usually 5m / min to 50m / min.

[0069] The laminate of the present invention has the above-mentioned cured product on at least one surface of a substrate. The substrate, coating method, irradiation conditions, etc. used are the same as those described above. Example

[0070] Hereinafter, the present invention will be described in detail by way of Examples and Comparative Examples. It should be noted that the technical scope of the present invention is certainly not limited thereto. In addition, unless otherwise specified, the "parts" and "%" in the examples are by mass.

[0071] Production Example 1 In a reaction apparatus equipped with a condenser, a stirrer, and a nitrogen inlet tube, 89.7 parts of polytetramethylene glycol (trade name: "PTMG2000", manufactured by Mitsubishi Chemical Corporation) (hereinafter referred to as PTMG2000), 9.2 parts of isophorone diisocyanate (hereinafter referred to as IPDI), 0.1 part of methylquinone (hereinafter referred to as MQ), and 0.1 part of stannous octoate were added. The temperature was raised to 70°C and maintained for 3 hours. Then, 1.1 parts of 2-isocyanatoethyl methacrylate (trade name: "Karenz MOI", manufactured by Showa Denko K.K.) (hereinafter referred to as Karenz MOI) was added. The temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane methacrylate (A-1) having a weight-average molecular weight of 60,000. The NCO value was measured in accordance with JIS K 1603-1 (hereinafter the same).

[0072] Production Example 2 Into the same reaction apparatus as in Production Example 1, 91.8 parts of PTMG2000, 7.1 parts of hexamethylene diisocyanate, 0.1 part of MQ, and 0.1 part of stannous octoate were added, the temperature was raised to 70°C, and the temperature was maintained for 3 hours. Then, 1.1 parts of Karenz MOI was added, and the temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane methacrylate (A-2) having a weight average molecular weight of 60,000.

[0073] Production Example 3 92.9 parts of polytetramethylene glycol (trade name: "PTMG3000", manufactured by Mitsubishi Chemical Corporation) (hereinafter referred to as PTMG3000), 6.4 parts of IPDI, 0.1 part of MQ, and 0.1 part of stannous octoate were added, the temperature was raised to 70°C and maintained for 3 hours, and then 0.7 parts of Karenz MOI was added. The temperature was maintained at 70°C for 2 hours, and the NCO value was measured to confirm the completion of the reaction. Thus, a polyurethane methacrylate (A-3) with a weight average molecular weight of 80,000 was obtained.

[0074] Production Example 4 Into the same reaction apparatus as in Production Example 1, 93.0 parts of PTMG3000, 6.4 parts of IPDI, 0.1 part of MQ, and 0.1 part of stannous octoate were added, the temperature was raised to 70°C, and the temperature was maintained for 3 hours. Then, 0.7 part of 2-isocyanatoethyl acrylate (trade name: "Karenz AOI", manufactured by Showa Denko K.K.) was added, and the temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane acrylate (A-4) having a weight average molecular weight of 80,000.

[0075] Comparative Manufacturing Example 1 Into the same reaction apparatus as in Production Example 1, 88.4 parts of polypropylene glycol (trade name: "Adeka Polyether P-2000", number average molecular weight: 2000, manufactured by ADEKA Corporation) (hereinafter referred to as P-2000), 10.6 parts of IPDI, 0.1 part of MQ, and 0.1 part of stannous octoate were added. The temperature was raised to 70°C and maintained for 3 hours. Then, 1.0 part of 4-hydroxybutyl acrylate (4HBA) was added, and the temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane acrylate (A'-1) having a weight average molecular weight of 60,000.

[0076] Comparative Manufacturing Example 2 Into the same reaction apparatus as in Production Example 1, 84.3 parts of PTMG2000, 12.5 parts of IPDI, 0.1 part of MQ, and 0.1 part of stannous octoate were added, the temperature was raised to 70°C, and the temperature was maintained for 3 hours. Then, 3.3 parts of 2-hydroxyethyl acrylate (2HEA) was added, and the temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane acrylate (A'-2) having a weight average molecular weight of 35,000.

[0077] Comparative Manufacturing Example 3 Into the same reaction apparatus as in Production Example 1, 98.5 parts of polypropylene glycol (trade name: "PREMINOL S4318F", number average molecular weight: 18,000, manufactured by AGC Corporation), 0.6 parts of IPDI, 0.1 parts of MQ, and 0.1 parts of stannous octoate were added. The temperature was raised to 70°C and maintained for 3 hours. Then, 0.9 parts of Karenz MOI was added, and the temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane methacrylate (A'-3) having a weight average molecular weight of 90,000.

[0078] Comparative Manufacturing Example 4 In the same reaction apparatus as in Production Example 1, 88.5 parts of PTMG2000, 10.7 parts of IPDI, 0.1 part of MQ, and 0.1 part of stannous octoate were added, the temperature was raised to 70°C, and the temperature was maintained for 3 hours. Then, 0.8 parts of 2-hydroxyethyl acrylate (2HEA) was added, and the temperature was maintained at 70°C for 2 hours. The NCO value was measured to confirm the completion of the reaction, thereby obtaining a polyurethane acrylate (A'-4) having a weight-average molecular weight of 220,000. However, due to its high viscosity, the following evaluation was not performed.

[0079] Example 1 Polyurethane methacrylate (A-1), 2-ethylhexyl acrylate as component (B1), isobornyl acrylate as component (B2), and 4-hydroxybutyl acrylate as component (C) were mixed in the mixing ratio shown in Table 1, and 1-hydroxycyclohexyl phenyl ketone (trade name: "LUNACURE200", manufactured by DKSH) as a photopolymerization initiator was further mixed to obtain an active energy ray-curable adhesive composition.

[0080] Examples 2 to 15, Comparative Examples 1 to 7 The same procedure as in Example 1 was carried out by changing the composition and content ratio shown in Table 1 to obtain active energy ray-curable adhesive compositions.

[0081] <Preparation of Pre-laminated Body> The adhesive composition of each embodiment and comparative example was coated on a 75 μm thick heavy-peel treated polyester film (trade name: "SP-PET-03-75BU", manufactured by PANAC Co., Ltd.) in such a way that the film thickness after curing became 400 μm, and the peel-treated surface of a 38 μm thick light-peel treated polyester film (trade name: "SP-PET-01-38BU", manufactured by PANAC Co., Ltd.) was attached to the coating layer. Then, a high pressure mercury lamp (100 mW / cm 2 , 900mJ / cm 2) is irradiated with ultraviolet rays to produce a pre-laminated body (light release treated polyester film / cured product / heavy release treated polyester film).

[0082] <Heat yellowing resistance> <Heat yellowing resistance> The light release polyester film was removed from the pre-laminated body and replaced with the pre-laminated body, which was then laminated to a glass plate using a 2 kg roller. The heavy release polyester film was then removed and laminated to the glass plate. The pre-laminated body was then autoclaved at 70°C and 0.5 MPa for 30 minutes to obtain a double-sided glass laminate (glass / cured product / glass). The obtained laminate was measured using a commercially available measuring instrument (trade name: "Color Meter SE7700", manufactured by Nippon Denshoku Industries Co., Ltd.) to measure the initial color difference (b * It should be noted that b * The value is the b including the substrate (glass plate) * The results are shown in Table 1 (the same below). If b * If it is 1 or less, the initial color difference is good, and the closer the value is to 0, the better it is. Next, the laminate was allowed to stand in a constant temperature and humidity chamber at 120° C. for 500 hours, and the color difference (b * value), calculate the color difference compared to the initial color (b * The change range of the value) (△b * ), and the heat yellowing resistance was evaluated according to the following criteria.

[0083] (Evaluation Criteria) A: The change in color difference (b* value) is less than 0.5 B: The change in color difference (b* value) is greater than 0.5 and less than 1 C: The change in color difference (b* value) is greater than 1

[0084] <Moisture and heat resistance (whitening and peeling)> The light release polyester film was removed from the pre-laminated body and replaced with the pre-laminated body, which was then laminated to a glass plate using a 2 kg roller. The heavy release polyester film was then removed and laminated to the glass plate. The pre-laminated body was then autoclaved at 70°C and 0.5 MPa for 30 minutes to obtain a double-sided glass laminate (glass / cured product / glass). The obtained laminate was allowed to stand in a constant temperature and humidity chamber at a temperature of 85° C. and a humidity of 85% for 500 hours, and the whitening and peeling of the cured product were visually observed and evaluated according to the following criteria.

[0085] (Evaluation Criteria) A: No bleaching or peeling B: Although there is no whitening, part of the base material has peeled off C: There is whitening and the base material has completely peeled off

[0086] <Adhesion> The lightly release-treated polyester film was removed from the pre-laminated structure and replaced with a 50 μm thick polyester film (trade name: "Cosmoshine A-4300", manufactured by Toyobo Co., Ltd.) using a 2 kg roller. The film was then left for 2 hours. A 2.5 cm x 8 cm test piece was then cut from the pre-laminated structure, and the heavy release-treated polyester film was removed to obtain a single-sided PSA sheet (Cosmoshine A-4300 / cured product). The resulting mixture was bonded to a glass plate using a 2 kg roller and allowed to stand for 24 hours under the conditions of a temperature of 25° C. and a humidity of 50% to produce a laminate (Cosmoshine A-4300 / cured material layer / glass). The adhesive strength (N / 25mm) of the cured product was measured using a commercially available testing machine (trade name: "TENSILON Universal Material Testing Machine," manufactured by A&D Co., Ltd.) by peeling a glass plate in the 180° direction at a rate of 300 mm / min. The high-temperature adhesive strength of the laminate was also measured in the same manner after the laminate was allowed to stand in a constant temperature and humidity chamber at 85°C for at least 2 hours. If the adhesive strength was 20 N / mm or greater at 25°C and 5 N / 25mm or greater at 85°C, the adhesive strength was considered good, with larger values ​​indicating superior adhesion.

[0087] [Table 1] *1: The ratio is expressed as the total of the components (A), (B), and (C) being 100% by mass. *2: Indicated as a ratio relative to 100% by mass of the total of the components (A), (B), and (C).

[0088] The symbols in Table 1 represent the following compounds. <Urethane (meth)acrylate> A-1: Polyurethane methacrylate of Production Example 1 A-2: Polyurethane methacrylate of Production Example 2 A-3: Polyurethane methacrylate of Production Example 3 A-4: Polyurethane acrylate of Production Example 4 A'-1: polyurethane acrylate of comparative preparation example 1 A'-2: polyurethane acrylate of comparative preparation example 2 A'-3: polyurethane methacrylate of comparative preparation example 3 <(B1) Ingredients> 2EHA: 2-ethylhexyl acrylate NOAA: n-octyl acrylate LA: Lauryl acrylate ISTA: Isostearyl acrylate (B2) Ingredients IBXA: Isobornyl acrylate FA-513AS: dicyclopentanyl acrylate, trade name: "FA-513AS", manufactured by Resonac Co., Ltd. <(C) Ingredient> 4HBA: 4-Hydroxybutyl acrylate 2HEA: 2-Hydroxyethyl acrylate <Tackifying Resin> D-1: Styrene resin (trade name: "FTR6125", styrene-aliphatic monomer copolymer, manufactured by Mitsui Chemicals, Inc.).

Claims

1. An active energy ray-curable adhesive composition comprising: A polyurethane (meth)acrylate (A) having a weight-average molecular weight of 50,000 to 200,000, wherein the polyurethane (meth)acrylate (A) is a reaction product of a chain polyether polyol (a1), a polyisocyanate (a2), and a mono(meth)acrylate (a3-1) having a hydroxyl group or a mono(meth)acrylate (a3-2) having an isocyanate group, wherein the chain polyether polyol (a1) has an alkylene chain having 4 or more carbon atoms as a repeating unit. a mono(meth)acrylate (B) having no hydroxyl group, and a mono(meth)acrylate (C) having a hydroxyl group; Component (B) is an alkyl mono(meth)acrylate (B1) having an alkyl group having 6 to 20 carbon atoms, and a cycloalkyl mono(meth)acrylate (B2). The ratio of the mass of the non-volatile components of the component (B1) to the component (B2) [(B1) / (B2)] is 0.05 or more and less than 1, When the total of the components (A), (B), and (C) is 100% by mass, the content of the component (C) is 10% by mass to 35% by mass. 2 . The active energy ray-curable adhesive composition according to claim 1 , further comprising a tackifier resin (D). 3 . A cured product of the active energy ray-curable adhesive composition according to claim 1 . A laminate comprising the cured product according to claim 3 on at least one surface of a substrate.

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