Photocurable composition and cured product thereof, photofusible resin composition, and adhesive kit

Abstract

The invention discloses a photocurable composition, which contains: a dithiol compound with a disulfide bond; a compound with two olefinic unsaturated groups; a hydrogen abstraction type photo free radical initiator; and an intramolecular cleavage type photo free radical initiator.

Description

Technical Field

[0001] The present invention relates to a photocurable composition and a cured product thereof, a photofusible resin composition, and an adhesive kit. Background Art

[0002] The photosoftening composition softened by light irradiation is used for various purposes. For example, Patent Document 1 discloses an image forming apparatus including a recording member having a photosoftening resin composed of a photosoftening resin composition.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 11-190883 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] General adhesives and temporary fixing materials are usually controlled by heating, such as bonding by curing with heat, peeling by softening with heat, or peeling by thermoplastic melting. However, in the characteristic control based on heating, there are cases where damage is applied to the substrate and the process operation time (takt time) is prolonged. Regarding temporary fixing materials, they are usually film products, so it is difficult to temporarily fix substrates with step differences, and the peeling mechanism also mostly utilizes the mechanism of curing shrinkage, foaming, and thermal expansion coefficient (CTE) difference, and usually stress is applied to the substrate. If it is a composition that is cured by light and melted by light, it is believed that the above-mentioned undesirable situation is unlikely to occur.

[0008] One object of the present invention is to provide a photocurable composition capable of forming a cured product that can be melted by light irradiation.

[0009] Means for solving technical problems

[0010] One aspect of the present invention is related to a photocurable composition, which contains: a dithiol compound having a disulfide bond; a compound having two ethylenically unsaturated groups; a hydrogen abstraction type photoradical initiator; and an intramolecular cleavage type photoradical initiator.

[0011] Since the photocurable composition contains: a dithiol compound having a disulfide bond; a compound having two ethylenically unsaturated groups; a hydrogen abstraction type photoradical initiator; and an intramolecular cleavage type photoradical initiator, it can form a cured product that can be melted by light irradiation.

[0012] The mechanism for obtaining this effect is, for example, inferred as follows, but is not limited thereto. First, when the photocurable composition is irradiated with the first light, a reaction (thiol-ene reaction) between a dithiol compound having a disulfide bond and a compound having two olefinically unsaturated groups is carried out by a hydrogen abstraction type photoradical initiator. Thus, a cured product of a photocurable composition comprising a reaction product based on a thiol-ene reaction and an intramolecular cleavage type photoradical initiator is formed. When the cured product of the photocurable composition is irradiated with the second light, the photocurable composition can be softened. Although the mechanism by which the photocurable composition can be softened is not yet clear, the following mechanism can be considered, for example. However, it is not limited to these mechanisms. First, the disulfide bonds in the photocurable composition are decomposed (cleaved) by irradiation with the second light, thereby generating thiol radicals. At this time, if an intramolecular cleavage type photoradical initiator is present in the photocurable composition, the thiol radicals react with the photoradical initiator, and the thiol radicals are capped by the photoradical initiator. Therefore, the following mechanism can be considered, that is, the molecular weight of the compound with a disulfide bond is reduced to soften the photocurable material. As another mechanism, the following mechanism can also be considered, that is, the photoinduced radical caused by the intramolecular cleavage type photoradical initiator directly reacts with the disulfide bond, causing the formation of a photoinduced radical-thioether bond and the generation of a thiol radical, and the thiol radical reacts with another photoinduced radical, and the molecular weight of the compound with a disulfide bond itself is reduced to soften the photocurable material. The first light includes light of a different wavelength from the second light. The first light may include light on the longer wavelength side than the second light. The first light may include light of a wavelength of 405nm. The second light may include light of a wavelength of 365nm. It can be said that the reaction of disulfide bond cleavage is an irreversible reaction.

[0013] The compound having two ethylenically unsaturated groups may be at least one compound selected from the group consisting of a compound having two allyl groups or a compound having two vinyloxy groups.

[0014] The extinction coefficient of the hydrogen abstraction type photoradical initiator at a wavelength of 405 nm may be greater than 7. The extinction coefficient of the intramolecular cleavage type photoradical initiator at a wavelength of 405 nm may be less than 5, and the extinction coefficient at a wavelength of 365 nm may be greater than 49.

[0015] The hydrogen abstraction type photo radical initiator may include at least one selected from the group consisting of fluorenone and benzyl. The intramolecular cleavage type photo radical initiator may include one selected from the group consisting of 2,2-dimethoxy-1,2-diphenylethane-1-one and 2-hydroxy-2-methyl-1-phenylpropanone. The photocurable composition may be an adhesive.

[0016] Another aspect of the present invention relates to a cured product of the above-mentioned photocurable composition. Another aspect of the present invention relates to an optically fusible resin composition, which contains: a reaction product of a dithiol compound having a disulfide bond and a compound having two ethylenically unsaturated groups; and an intramolecular cleavage type photo-radical initiator.

[0017] Another aspect of the present invention relates to an adhesive kit, which comprises: a first component containing a dithiol compound having a disulfide bond; and a second component containing a compound having two ethylenically unsaturated groups, at least one of the first and second components further containing a hydrogen abstraction type photo-radical initiator, and at least one of the first and second components further containing an intramolecular cleavage type photo-radical initiator.

[0018] Effects of the Invention

[0019] According to one aspect of the present invention, there is provided a photocurable composition capable of forming a cured product that can be melted by light irradiation. According to one aspect of the present invention, there is provided a cured product of the photocurable composition, a photofusible resin composition using the photocurable composition, and an adhesive kit. DETAILED DESCRIPTION

[0020] Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments.

[0021] In this specification, the term "process" includes not only independent processes, but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved. In addition, a numerical range represented by "to" indicates a range that includes the numerical values ​​recorded before and after "to" as the minimum and maximum values, respectively.

[0022] In addition, in this specification, when there are multiple substances corresponding to each component in the composition, the content of each component in the composition refers to the total amount of the multiple substances present in the composition unless otherwise specified. In addition, the exemplified materials may be used alone or in combination of two or more unless otherwise specified.

[0023] Furthermore, in the numerical ranges recorded in stages in this specification, the upper limit or lower limit of the numerical range of a certain stage may also be replaced by the upper limit or lower limit of the numerical range of other stages. Furthermore, in the numerical ranges recorded in this specification, the upper limit or lower limit of the numerical range may be replaced by the values ​​shown in the embodiments. "A or B" may include either A or B, or both.

[0024] [Photocurable composition]

[0025] A photocurable composition according to one embodiment contains: a dithiol compound having a disulfide bond (hereinafter, sometimes referred to as component (A-1)); a compound having two ethylenically unsaturated groups (hereinafter, sometimes referred to as component (A-2)); a hydrogen abstraction type photoradical initiator (hereinafter, sometimes referred to as component (B-1)); and an intramolecular cleavage type photoradical initiator (hereinafter, sometimes referred to as component (B-2)).

[0026] (A-1) Component: dithiol compound having a disulfide bond

[0027] The component (A-1) is a compound having a disulfide bond (-SS-) and two thiol groups (-SH). The component (A-1) may be a high molecular weight component of a polymer or an oligomer. The component (A-1) may also be referred to as a compound consisting of two thiol groups and a group (first linking group) that includes a disulfide bond and connects the two thiol groups.

[0028] The molecular weight or weight average molecular weight of the component (A-1) may be 200 to 10,000,000, 200 to 3,000,000, 500 to 1,000,000, or 1,000 to 10,000. The weight average molecular weight is a polystyrene conversion value obtained by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene.

[0029] The component (A-1) has one or more (two or more) disulfide bonds in the molecule. The number of disulfide bonds in the component (A-1) may be, for example, 1 to 1,000 or 4 to 50.

[0030] The component (A-1) may be a compound (e.g., a polymer or oligomer) having a linear molecular chain and an end group and having a disulfide bond in the molecular chain. In this case, the end group in the component (A-1) may be a thiol group. When the component (A-1) is such a compound, it is easier to form a cured product having excellent optical solubility. The molecular chain in the component (A-1) may contain a disulfide bond and a polyether chain, or may consist of a disulfide bond and a polyether chain.

[0031] The component (A-1) can be, for example, a compound of formula (1): HS-(ASS) n1 -A-SH represented by the compound (compound (1)) or a compound obtained by extending the chain of the compound. In the formula, A represents a polyether chain. A plurality of A's may be the same or different. n1 represents an integer greater than 1. n1 may be, for example, greater than 1 or greater than 4, or less than 1000. When the component (A-1) is a compound represented by the formula (1), -(ASS) n1The group represented by -A- is the first connecting group. The compound obtained by chain extension of compound (1) may be, for example, a Michael adduct of compound (1) or a thiol carbamate of compound (1). The Michael adduct of compound (1) as component (A-1) is a reaction product of a compound (e.g., diacrylate) having a group (e.g., acryloyl) that can react with a thiol group and form a bond by a Michael addition reaction, and is a compound having two thiol groups. The thiol carbamate of compound (1) as component (A-1) is a reaction product of a diisocyanate and compound (1), and is a compound having two thiol groups.

[0032] The polyether chain as A may be, for example, a polyoxyalkylene chain. The polyether chain as A may be, for example, a 1 -OA 2 -OA 3 -represented by a group. 1 ~A 3 Each of them may be independently an alkylene group, or an alkylene group having 1 to 2 carbon atoms (e.g., methylene group, ethylene group). Examples of the polyether chain of A include -CH 2 CH 2 -O-CH 2 -O-CH 2 CH 2 -wait.

[0033] As commercial products of component (A-1), for example, polysulfide rubber LP series (dithiol with disulfide bond, manufactured by TORAY FINE CHEMICALS CO., LTD.) etc. can be listed. Component (A-1) can be used alone or in combination of two or more. Component (A-1) can also be obtained by converting the reactive functional group of a compound having a reactive functional group (e.g., carboxyl, hydroxyl) and a disulfide bond at the end into a thiol group. As compounds having a reactive functional group and a disulfide bond at the end, 3,3'-dithiodipropionic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), dithiodiethanol, cystamine etc. can be listed.

[0034] The content of the component (A-1) may be 50% by mass or more, 60% by mass or more, 70% by mass or more, 75% by mass or more, or 80% by mass or less, or 95% by mass or less, or 90% by mass or less, or 85% by mass or less, based on the total mass of the photocurable composition.

[0035] Component (A-2): Compound having two ethylenically unsaturated groups

[0036] The component (A-2) is a compound having two ethylenically unsaturated groups (C=C) in the molecule. The component (A-2) can also be referred to as a compound consisting of two ethylenically unsaturated groups and a group connecting the two ethylenically unsaturated groups (second connecting group).

[0037] The second connecting group is a group capable of connecting two ethylenically unsaturated groups, and may be, for example, a substituted or unsubstituted divalent hydrocarbon group. Examples of the hydrocarbon group include divalent aromatic groups and alkylene groups such as phenylene. The substituted hydrocarbon group may be a group consisting of the above hydrocarbon group and a group containing an oxygen atom. Examples of the group containing an oxygen atom include an oxy group (-O-), an ester group (-OC(=O)-), etc. The group containing an oxygen atom may be a polyoxyalkylene group such as polyoxyethylene.

[0038] The component (A-2) may be, for example, a component having an allyl group (H 2 C=CH-CH 2 -), vinyloxy (H 2 C=CH-O-) and a compound having two groups selected from the group consisting of a (meth)acryloyl group. From the viewpoint of further improving the photocurability and the viewpoint that the cured product becomes easier to liquefy by light irradiation, a compound having two groups selected from the group consisting of an allyl group and a vinyloxy group may be included. (A-2) Component may include a compound having two allyl groups or a compound having two vinyloxy groups. From the viewpoint of better curability, a compound having two ethylenically unsaturated groups may, for example, include a compound having two vinyloxy groups. (Meth)acryloyl is a methacryloyl group or an acryloyl group.

[0039] Examples of the component (A-2) include dipropylene terephthalate, triethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, diethylene glycol divinyl ether, 1,4-butanediol divinyl ether, etc. The component (A-2) may be used alone or in combination of two or more.

[0040] The content of the component (A-2) may be 1.0% by mass or more, 2.0% by mass or more, 3.0% by mass or more, 3.5% by mass or more, or 4.0% by mass or less, or 30% by mass or less, 20.0% by mass or less, 10.0% by mass or less, or 5.0% by mass or less, based on the total mass of the photocurable composition.

[0041] The molar ratio of the component (A-1) to the component (A-2) (component (A-1) / component (A-2)) may be, for example, 0.8 to 1.2, 0.9 to 1.1, or 0.98 to 1.02.

[0042] (B-1) Component: Hydrogen abstraction type photo-radical initiator

[0043] The component (B-1) is a compound that generates radicals by abstracting hydrogen from other molecules when irradiated with light. As the component (B-1), a compound that is used as a hydrogen abstraction type photoradical polymerization initiator can be used.

[0044] Examples of the component (B-1) include hexaarylbiimidazole (HABI) compounds, benzophenone compounds, thioxanthone compounds, fluorenone compounds, and α-diketone compounds. The component (B-1) may be used alone or in combination of two or more.

[0045] Examples of the HABI compound include 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetraphenylbiimidazole (e.g., 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl-1,2'-biimidazole), 2,2'-bis(o-bromophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(o-,p-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, Tetraphenylbiimidazole, 2,2'-bis(o-chlorophenyl)-4,4',5,5'-tetra(m-methoxyphenyl)biimidazole, 2,2'-bis(o,o'-dichlorophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(o-nitrophenyl)-4,4',5,5'-tetraphenylbiimidazole, 2,2'-bis(o-methylphenyl)-4,4',5,5'-tetraphenylbiimidazole, etc.

[0046] Examples of the benzophenone compound include 4,4′-bis(dimethylamino)benzophenone and 4,4′-bis(diethylamino)benzophenone.

[0047] Examples of the thioxanthone compound include thioxanthone, 2-isopropyl thioxanthone, 2-dodecyl thioxanthone, 2-cyclohexyl thioxanthone, 2,4-diethyl thioxanthone, 2,4-dimethyl thioxanthone, 1-phenoxy thioxanthone, 1-methoxycarbonyl thioxanthone, 2-ethoxycarbonyl thioxanthone, 3-(2-methoxyethoxycarbonyl)-thioxanthone, 4-butoxycarbonyl thioxanthone, 3-butoxycarbonyl-7-methyl thioxanthone, 3,4-di-[2-(2-methoxyethoxy)-ethoxycarbonyl]-thioxanthone, 2-chlorothioxanthone, 1-ethoxycarbonyl-3-thioxanthone, -ethoxythioxanthone, 1-ethoxycarbonyl-3-chlorothioxanthone, 1-chloro-4-n-propoxythioxanthone, 2-methyl-6-dimethoxymethyl-thioxanthone, 2-methyl-6-(1,1-dimethoxybenzyl)-thioxanthone, 6-ethoxycarbonyl-2-methoxy-thioxanthone, 6-ethoxycarbonyl-2-methylthioxanthone, 1-ethoxycarbonyl-3-(1-methyl-1-morpholinylethyl)-thioxanthone, 2-morpholinylmethylthioxanthone, 2-methyl-6-morpholinylmethylthioxanthone, thioxanthone-2-carboxylic acid polyethylene glycol ester, etc.

[0048] Examples of the fluorenone compound include 9-fluorenone, 3,4-benzo-9-fluorenone, 2-dimethylamino-9-fluorenone, 2-methoxy-9-fluorenone, 2-chloro-9-fluorenone, 2,7-dichloro-9-fluorenone, 2-bromo-9-fluorenone, 2,7-dibromo-9-fluorenone, 2-nitro-9-fluorenone, and 2-acetoxy-9-fluorenone.

[0049] Examples of the α-diketone compound include benzyl (also referred to as diphenyldione or dibenzoyl compounds.

[0050] The component (B-1) may be, for example, a compound that absorbs light at a wavelength of 405 nm. The component (B-1) may be a compound that has a larger extinction coefficient at a wavelength of 405 nm than the component (B-2).

[0051] The extinction coefficient of the component (B-1) at a wavelength of 405 nm may be greater than 7. When the extinction coefficient of the component (B-1) at a wavelength of 405 nm is within the above range, the effect of the present invention is more significant.

[0052] In this specification, the absorption coefficients of Omnirad TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), Omnirad 754, and Omnirad MBF are values ​​measured in acetonitrile, and the absorption coefficients of other compounds are values ​​measured in methanol (unit: mL / g·cm).

[0053] Examples of the component (B-1) having an extinction coefficient of 7 or more at a wavelength of 405 nm include 2,2′-bis(o-chlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole and 9-fluorenone.

[0054] The content of the component (B-1) may be 0.5 parts by mass or more, 1.5 parts by mass or more, 3 parts by mass or more, or 4 parts by mass or more relative to 100 parts by mass of the photocurable composition. The content of the component (B-1) may be 20 parts by mass or less, 15 parts by mass or less, 10 parts by mass or less, or 7 parts by mass or less relative to 100 parts by mass of the photocurable composition.

[0055] (B-2) Component: Intramolecular cleavage type photoradical initiator

[0056] The component (B-2) is a compound that generates two radicals by photolysis upon irradiation with light. As the component (B-2), a compound that functions as an intramolecular cleavage-type photoradical polymerization initiator can be used.

[0057] Examples of the intramolecular cleavage type photoradical initiator include benzyl ketal photoradical initiators, α-aminoalkylphenone photoradical initiators, α-hydroxyalkylphenone photoradical initiators, α-hydroxyacetophenone photoradical initiators, and acylphosphine oxide photoradical initiators. Component (B-2) may be used alone or in combination of two or more.

[0058] Examples of the benzyl ketal-based photoradical initiator include 2,2-dimethoxy-1,2-diphenylethane-1-one (Omnirad 651) and the like.

[0059] Examples of α-aminoalkylphenone-based photoradical initiators include 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (Omnirad369), 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropane-1-one (Omnirad907), and 2-dimethylamino-2-(4-methyl-benzyl)-1-(4-morpholino-4-yl-phenyl)-butane-1-one (Omnirad379EG).

[0060] Examples of the α-hydroxyalkylphenone-based photoradical initiator include 1-hydroxy-cyclohexyl-phenyl-ketone (Omnirad 184) and the like.

[0061] Examples of the α-hydroxyacetophenone-based photoradical initiator include 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propane-1-one (Omnirad 127) and 2-hydroxy-2-methyl-1-phenyl-propane-1-one (Omnirad 1173).

[0062] Examples of the acylphosphine oxide-based photoradical initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (Omnirad TPO H) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Omnirad 819).

[0063] The component (B-2) may be a compound that absorbs light at a wavelength of 365 nm and substantially does not absorb light at a wavelength of 405 nm or has an absorption coefficient at a wavelength of 405 nm that is smaller than that of the component (B-1). The absorption coefficient at a wavelength of 365 nm of the component (B-2) may be 49 or more. In the present specification, "substantially does not absorb light at a wavelength of 405 nm" means that the absorption coefficient at a wavelength of 405 nm is 5 or less. The component (B-2) may be a compound that has an absorption coefficient at a wavelength of 365 nm of 49 or more and an absorption coefficient at a wavelength of 405 nm of 5 or less. When the absorption coefficient at a wavelength of 405 nm and the absorption coefficient at a wavelength of 365 nm of the component (B-2) are within the above ranges, the effect of the present invention is more significant.

[0064] Examples of the component (B-2) having an extinction coefficient of 49 or more at a wavelength of 365 nm and an extinction coefficient of 5 or less at a wavelength of 405 nm include Omnirad651, Omnirad1173, and Omnirad184.

[0065] The content of the component (B-2) may be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, 10 parts by mass or more, 15 parts by mass or more, or 25 parts by mass or more, relative to 100 parts by mass of the photocurable composition. The content of the component (B-2) may be 50 parts by mass or less, 40 parts by mass or less, 35 parts by mass or less, or 30 parts by mass or less, relative to 100 parts by mass of the photocurable composition.

[0066] The combination of the component (B-1) and the component (B-2) may be a combination of fluorenone and 2,2-dimethoxy-1,2-diphenylethane-1-one, a combination of benzyl and 2-hydroxy-2-methyl-1-phenylpropanone, a combination of benzyl and 2,2-dimethoxy-1,2-diphenylethane-1-one, or a combination of benzyl and 1-hydroxy-cyclohexyl-phenyl-ketone.

[0067] In the photocurable composition, the hydrogen abstraction type photoradical initiator may include at least one selected from the group consisting of fluorenone and benzyl, and the intramolecular cleavage type photoradical initiator may include one selected from the group consisting of 2,2-dimethoxy-1,2-diphenylethane-1-one and 2-hydroxy-2-methyl-1-phenylpropanone.

[0068] The photocurable composition may also include other ingredients other than (A-1) component, (A-2) component, (B-1) component and (B-2) component. As other ingredients, for example, adhesive imparting agents such as plasticizers and tackifiers, antioxidants, leuco dyes, sensitizers, adhesion improvers such as coupling agents, inhibitors, light stabilizers, defoamers, fillers, chain transfer agents, thixotropy imparting agents, flame retardants, release agents, surfactants, lubricants, antistatic agents and other additives can be listed. These additives can use known additives. The total amount of the content of other ingredients is based on the total amount of the photocurable composition, and can be 0 to 95% by mass, 0.01 to 50% by mass or 0.1 to 10% by mass.

[0069] The photocurable composition can be used as a varnish of the photocurable composition diluted with a solvent. Examples of the solvent component include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene, and p-isopropylbenzene; aliphatic hydrocarbons such as hexane and heptane; cycloalkanes such as methylcyclohexane; cyclic ethers such as tetrahydrofuran and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate, butyl acetate, methyl lactate, ethyl lactate, and γ-butyrolactone; carbonates such as ethylene carbonate and propylene carbonate; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone (NMP), etc. Component (E) can be used alone or in combination of two or more. The solid content in the varnish, that is, the total content of the varnish other than the solvent, may be 10 to 95% by mass, 15 to 70% by mass, or 20 to 50% by mass based on the total mass of the varnish.

[0070] The photocurable composition can be prepared, for example, by a method comprising the steps of mixing or kneading the components (A-1), (A-2), (B-1), (B-2), and (A-3), and optionally added components. The mixing and kneading can be performed by appropriately combining a conventional dispersing machine such as a stirrer, a pestle, a three-roll mill, a ball mill, or a bead mill.

[0071] The photocurable composition can form a cured product by light irradiation. By irradiating the photocurable composition with light, a thiol-ene reaction with the components (A-1) and (A-2) is carried out. The thiol-ene reaction is carried out starting from the hydrogen abstraction type photo radical initiator abstracting the hydrogen of the thiol group in the component (A-1) during light irradiation. The reaction product of the components (A-1) and (A-2) includes, for example, a compound represented by the following formula. The cured product contains: the reaction product of the components (A-1) and (A-2); and an intramolecular cleavage type photo radical initiator.

[0072]

[0073] In the formula, X represents the first linking group, and Y represents the second linking group. m represents an integer greater than 1. For example, m can be greater than 25, greater than 50, greater than 100, or greater than 250.

[0074] For example, by irradiating the photocurable composition with a first light having a wavelength of 405 nm, a cured product of the photocurable composition can be formed. The exposure amount of the first light can be, for example, 20,000 mJ / cm 2In this specification, the exposure amount refers to the product of the illumination intensity and the irradiation time (seconds). The irradiation of light can be performed directly on the irradiated object or through glass, etc. There is no particular limitation on the light source used for light irradiation, and examples thereof include LED lamps, mercury lamps (low pressure, high pressure, ultra-high pressure, etc.), metal halide lamps, excimer lamps, xenon lamps, etc., and LED lamps, mercury lamps, metal halide lamps, etc. are preferred.

[0075] The cured product of the photocurable composition can be formed into various shapes. For example, a cured product formed into a film (film) can be used as a resin film. A cured product formed into a block can be used as a resin block. The method for forming a cured product in a film (film) or block form is not particularly limited, and a known method can be applied.

[0076] The storage modulus of the cured product of the photocurable composition at 25°C may be 5000 Pa or more, 7000 Pa or more, or 100000 Pa or more. The storage modulus of the cured product of the photocurable composition at 25°C is not particularly limited, and may be, for example, 1000 MPa or less. In this specification, the storage modulus at 25°C refers to a value measured by the method described in the Examples.

[0077] The cured product has the property of being photo-melted by light irradiation. For example, by irradiating the second light including light of wavelength 365nm, the cured product can be melted. The exposure amount of the second light can be, for example, 5000mJ / cm 2 The above. The irradiation of light may be performed directly on the irradiated object, or may be performed through glass, etc. The light source, etc. when performing the light irradiation may be the same as described above.

[0078] When irradiated with light, the intramolecular cleavage type photo-radical initiator cleaves the disulfide bond (-SS-) in the reaction product of the components (A-1) and (A-2). As a result, the reaction product of the components (A-1) and (A-2) is reduced in molecular weight and becomes liquid (liquid). The cured product of the above-mentioned photocurable composition melts by irradiation with light, so it can also be called a photofusible composition. The photofusible composition contains: a reaction product of the components (A-1) and (A-2); and an intramolecular cleavage type photo-radical initiator.

[0079] The storage modulus of the cured product of the photocurable composition after light irradiation at 25° C. may be 100 Pa or less, 10 Pa or less, or 8.5 Pa or less. The storage modulus of the cured product of the photocurable composition at 25° C. is not particularly limited and may exceed 0 MPa, for example.

[0080] The photocurable composition of the present embodiment can be used for applications such as adhesives, temporary fixing materials, photoresists, resins for 3D printers, and resins for molding materials.

[0081] The adhesive kit of this embodiment includes: a first component containing a dithiol compound having a disulfide bond (component (A-1)) and a second component containing a compound having two ethylenically unsaturated groups (component (A-2)). At least one of the first component and the second component further contains a hydrogen abstraction type photo-radical initiator (component (B-1)), and at least one of the first component and the second component further contains an intramolecular cleavage type photo-radical initiator (component (B-2)). At least one of the first component and the second component may further contain the above-mentioned other components.

[0082] When the first component and the second component are mixed, the equivalent ratio (molar ratio) of the component (A-1) to the component (A-2) may be, for example, 0.8 to 1.2.

[0083] The adhesive kit of the present embodiment can prepare an adhesive composition by mixing the first component and the second component. The temperature and time for mixing the first component and the second component can be, for example, 10 to 35° C. and 0.1 to 60 minutes.

[0084] Examples of a method for mixing the first component and the second component include a method of manually mixing using a spatula or the like, a method of mixing by manual application using a conventional filling gun, and a method of mixing using a mechanical rotary mixer, a static mixer, or the like using a quantitative pump (e.g., a gear pump, a plunger pump, etc.) and a throttle valve for liquid delivery of the raw materials.

[0085] The prepared adhesive composition can form a cured product of the adhesive composition by light irradiation, and can function as an adhesive layer for bonding adherends to each other. For example, the adhesive composition can be cured by irradiating light including light having a wavelength of 405 nm.

[0086] The adhesive composition including the first component and the second component has adhesiveness, and a cured product of the adhesive composition has photosensitivity due to light irradiation. Therefore, the adhesive composition can also be used as an adhesive having repairability.

[0087] An adhesive body according to one embodiment includes a first adherend, a second adherend, and an adhesive layer for bonding the first adherend and the second adherend to each other. The adhesive layer contains a cured product of a photocurable composition.

[0088] Examples of the first adherend and the second adherend include plastics such as polyolefin resin, polyamide resin, ABS, PC, PET, PPS, and acrylic resin, and inorganic materials such as wood, rubber, steel, stainless steel, aluminum, copper, nickel, chromium, or alloys thereof, glass, and silicon wafers.

[0089] The adhesive body includes a step of bonding the first adherend and the second adherend via a photocurable composition. The curing conditions and the like may be the same as those described above.

[0090] The method for separating adherends of one embodiment includes a step of separating a first adherend and a second adherend by irradiating an adhesive layer of the adhesive body with light. Since the adhesive layer contains a cured product of the photocurable composition described above, the cured product of the photocurable composition can be melted by irradiating light, and the adherends can be easily separated from each other.

[0091] In the method for separating an adherend, the type of light, light source, etc. when irradiating light may be the same as those described above.

[0092] Example

[0093] Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0094] The compounds shown below were prepared.

[0095] (A-1) Ingredients:

[0096] Polysulfide rubber LP-55 (dithiol compound having a disulfide bond, manufactured by TORAY FINE CHEMICALS CO., LTD.)

[0097] (A-2) Ingredients:

[0098] ·Dipropylene terephthalate (number of allyl groups: 2, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0099] ·Triethylene glycol divinyl ether (number of vinyl ether groups: 2, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0100] (B-1) Ingredients:

[0101] ·Fluorenone (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0102] Benzyl (manufactured by FUJIFILM Wako Pure Chemical Corporation)

[0103] (B-2) Ingredients:

[0104] 2,2-Dimethoxy-1,2-diphenylethane-1-one (manufactured by IGM Resins BV, trade name Omnirad 651)

[0105] 2-Hydroxy-2-methyl-1-phenylpropanone (manufactured by IGM Resins BV, trade name Omnirad 1173)

[0106] [Preparation of photopolymerizable compound]

[0107] To a 125 ml ointment jar were added the components (A-1), (A-2), (B-1), and (B-2) in the amounts and quantities (unit: parts by mass) listed in Table 1, and mixed at 2000 rpm for 3 minutes using a self-revolving stirrer (manufactured by THINKY CORPORATION, trade name: Awatorirentarou ARE-310). Subsequently, each ointment jar was heated at 90° C. for 1 hour using a box-type dryer, and then mixed again at 2000 rpm for 3 minutes using a self-revolving stirrer to obtain a photocurable composition.

[0108] Using a viscoelasticity measuring device (manufactured by TA Instruments, trade name: DHR-2), the storage modulus change at 25°C relative to the light irradiation time was measured by irradiating the evaluation sample with ultraviolet light from the bottom surface of the light transmission. The light irradiation was performed using an LED lamp (manufactured by Panasonic Industrial Devices SUNX Co., Ltd., trade name: AicureUJ30 / ANUJ6186 and ANUJ6189), and the wavelength and exposure amount shown in Table 1 were used as the first wavelength. Then, exposure was performed with the wavelength and exposure amount shown in Table 1 as the second wavelength. Table 1 shows the storage modulus results at 25°C before light irradiation, after light irradiation with the first wavelength, and after light irradiation with the second wavelength.

[0109] [Table 1]

[0110]

[0111] As shown in Table 1, a cured product that can be melted by light irradiation can be formed in a photocurable composition containing a dithiol compound having a disulfide bond, a compound having two ethylenically unsaturated groups, a hydrogen abstraction type photoradical initiator, and an intramolecular cleavage type photoradical initiator.

Claims

1. A photocurable composition comprising: dithiol compounds having disulfide bonds; Compounds having 2 ethylenically unsaturated groups; Hydrogen abstraction type photo-radical initiators; and Intramolecular cleavage type photo-radical initiator, in, The compound having two ethylenically unsaturated groups is a compound having two allyl groups or a compound having two vinyloxy groups.

2. The photocurable composition according to claim 1, in, The absorption coefficient of the hydrogen abstraction type photo-radical initiator at a wavelength of 405 nm is greater than 7, The intramolecular cleavage type photo-radical initiator has an extinction coefficient of 5 or less at a wavelength of 405 nm and an extinction coefficient of 49 or more at a wavelength of 365 nm.

3. The photocurable composition according to claim 1 or 2, in, The hydrogen abstraction type photo-radical initiator includes at least one selected from the group consisting of fluorenone and benzyl.

4. The photocurable composition according to claim 1 or 2, in, The intramolecular cleavage type photoradical initiator includes one selected from the group consisting of 2,2-dimethoxy-1,2-diphenylethane-1-one and 2-hydroxy-2-methyl-1-phenylpropanone.

5. The photocurable composition according to claim 1 or 2, which is used for an adhesive. 6 . A cured product of the photocurable composition according to claim 1 .

7. An optically fusible resin composition comprising: A reaction product obtained by reacting a dithiol compound having a disulfide bond with a compound having two ethylenically unsaturated groups using a hydrogen abstraction type photoradical initiator; and Intramolecular cleavage type photo-radical initiator, in, The compound having two ethylenically unsaturated groups is a compound having two allyl groups or a compound having two vinyloxy groups.

8. An adhesive kit comprising: The first component comprises a dithiol compound having a disulfide bond; and The second component comprises a compound having two ethylenically unsaturated groups, At least one of the first component and the second component further contains a hydrogen abstraction type photo-radical initiator, At least one of the first component and the second component further contains an intramolecular cleavage type photo-radical initiator, in, The compound having two ethylenically unsaturated groups is a compound having two allyl groups or a compound having two vinyloxy groups.

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