Photocurable resin composition for temporary fixing, masking or molding

Abstract

To provide a photocurable resin composition for temporary fixing, masking or molding which is cured by irradiation with energy rays, where its cured product is less likely to absorb water, and has high solubility to at least one of acetone and methylcyclohexane.SOLUTION: A photocurable resin composition for temporary fixing, masking or molding contains a radical polymerization reactive component (A), a chain transfer agent (B) and a photopolymerization initiator (C), wherein the component (A) contains a radical polymerization reactive monomer (A1) having a cyclic structure that does not contain one or more atoms selected from O and N, in the component (A), the content of a radical polymerization reactive monomer (A2) having an OH group is 0 wt.% or more and less than 60 wt.%, and the content of a bi- or higher oligomer and a bi- or higher monomer (A3) is 0 wt.% or more and less than 15 wt.%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photocurable resin composition for temporary fixing, masking or molding. [Background technology]

[0002] Compositions that dissolve in water or organic solvents after being cured with ultraviolet (UV) light are expected to be applied in various fields, such as for molding applications such as temporary fixing and masking agents during component processing, and pedestals (support materials) during 3D printer printing. Patent Document 1 discloses a photocurable resin composition that gives a cured product that dissolves in water. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-122120 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is difficult to use the cured product of the photocurable resin composition disclosed in Patent Document 1 for components that dislike water. On the other hand, even if it is not soluble in water, the cured product that is easy to absorb water absorbs water during processing and changes in thickness and hardness, so it is often difficult to apply it to applications such as temporary fixing, masking, or molding. Furthermore, since many of the cured products that are easy to absorb water also have hygroscopic properties, there is a risk that they will absorb moisture and change in size if left for a certain period of time, and there are concerns about their use in applications such as temporary fixing or molding. For this reason, there is a need for the development of a composition that is difficult to absorb water and dissolves in organic solvents such as acetone and methylcyclohexane, which are less toxic.

[0005] An object of the present invention is to provide a photocurable resin composition for temporary fixing, masking or molding, which is cured by irradiation with energy rays, and the cured product is unlikely to absorb water and has high solubility in at least one of acetone and methylcyclohexane. [Means for solving the problem]

[0006] The present invention relates to the following: [1] A photocurable resin composition for temporary fixing, masking, or molding, comprising a radical polymerization reactive component (A), a chain transfer agent (B), and a photopolymerization initiator (C), Component (A) contains a radical polymerization reactive monomer (A1) having a cyclic structure that does not contain one or more atoms selected from O and N, A photocurable resin composition for temporary fixing, masking or molding, characterized in that in component (A), the content of the radical polymerization reactive monomer (A2) having an OH group is 0% by weight or more and less than 60% by weight, and the content of the difunctional or higher oligomer and difunctional or higher monomer (A3) is 0% by weight or more and less than 15% by weight. [2] The photocurable resin composition of [1], wherein the content of the radical polymerization reactive monomer (A4) having a heterocyclic structure containing O and / or N in component (A) is 0% by weight or more and 60% by weight or less. [3] The photocurable resin composition according to [1] or [2], wherein the content of component (A1) in component (A) is 40% by weight or more. [4] The photocurable resin composition according to any one of [1] to [3], wherein the component (B) is a compound having an α-methylstyrene structure or a compound having a thiol group. [5] The photocurable resin composition according to any one of [1] to [4], wherein the content of component (B) in the photocurable resin composition is 0.5 to 10% by weight. [6] The photocurable resin composition according to any one of [1] to [5], further comprising a polymer component (D). [7] The photocurable resin composition according to [6], wherein component (D) is a hydrogenated diene-based polymer. Effect of the Invention

[0007] According to the present invention, there is provided a photocurable resin composition for temporary fixing, masking or molding which is cured by irradiation with energy rays, and further the cured product is unlikely to absorb water and has high solubility in at least one of acetone and methylcyclohexane. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [Terminology definition] The term "(meth)acrylate" refers to at least one of acrylate and methacrylate. The term "(meth)acryloyl group" refers to at least one of an acryloyl group and a methacryloyl group. The "radical polymerization reactive component (A)" is also referred to as "component (A)." The same applies to the "chain transfer agent (B)" and the like. With regard to numerical ranges, "to" means that both ends of the range are included. Furthermore, "less than" means "the same as or less than," and "more than" means "the same as or more than." In other words, "0.5% to 10% by weight" means "0.5% by weight or more and 10% by weight or less," and includes the meanings of "more than 0.5% by weight and 10% by weight or less," "more than 0.5% by weight and less than 10% by weight," and "more than 0.5% by weight and less than 10% by weight."

[0009] [Photocurable resin composition for temporary fixing, masking or molding] The photocurable resin composition for temporary fixing, masking or molding (hereinafter also simply referred to as "photocurable resin composition") comprises a radical polymerization reactive component (A), a chain transfer agent (B) and a photopolymerization initiator (C), in which the component (A) comprises a radical polymerization reactive monomer (A1) having a cyclic structure not containing one or more atoms selected from O and N, the content of the radical polymerization reactive monomer (A2) having an OH group in the component (A) is 0% by weight or more and less than 60% by weight, and the content of the difunctional or higher oligomer and difunctional or higher monomer (A3) is 0% by weight or more and less than 15% by weight.

[0010] The photocurable resin composition is soluble in at least one of acetone and methylcyclohexane with low toxicity. Therefore, the photocurable resin composition can be a composition for dissolving in at least one of acetone and methylcyclohexane. Here, the photocurable resin composition may be soluble in acetone but not in methylcyclohexane, may be soluble in methylcyclohexane but not in acetone, or may be soluble in both acetone and methylcyclohexane.

[0011] <(Radical polymerization reactive component (A))> The radical polymerization reactive component (A) is not particularly limited as long as it has a radical polymerization reactive functional group, and examples include radical polymerization reactive oligomers and radical polymerization reactive monomers. The radical polymerization reactive functional group is not particularly limited as long as it is an unsaturated double bond-containing group, but an alkenyl group (for example, a vinyl group, an allyl group, etc.) or a (meth)acryloyl group is preferable, and a (meth)acryloyl group is particularly preferable. Component (A) may consist only of the above-mentioned component (A1), or may contain a predetermined amount of a radical polymerization reactive oligomer and / or monomer in addition to the above-mentioned component (A1). Further, component (A) may consist only of a radical polymerization reactive monomer, or may be a mixture of a radical polymerization reactive monomer and a radical polymerization reactive oligomer.

[0012] In component (A), the weight average molecular weight of the radical polymerization reactive oligomer is preferably 1,500 or more, and particularly preferably 1,500 to 50,000. As a method for measuring the weight average molecular weight, for components with relatively high molecular weights such as oligomers and polymers, a method of converting the measurement results of gel permeation chromatography (GPC) using a calibration curve of standard polystyrene is generally known. Further, since the monomer does not have a molecular weight distribution, it can be determined from the structural formula.

[0013] <<Radical polymerization reactive monomer (A1) having a cyclic structure containing no atom selected from O and N>> Component (A1) is a radically polymerizable monomer having a cyclic structure that does not contain one or more atoms selected from O and N. The cyclic structure may be a monocyclic or polycyclic structure. Further, the cyclic structure may be an alicyclic structure or an aromatic ring structure. The total number of atoms constituting one alicyclic structure is not particularly limited, but is preferably 3 to 20. The total number of atoms constituting one aromatic ring structure is not particularly limited, but is preferably 6 to 20. The cyclic structure preferably consists of only carbon atoms. Component (A1) is preferably an alicyclic (meth)acrylate monomer or an aromatic (meth)acrylate monomer.

[0014] Examples of the alicyclic (meth)acrylate monomer include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl oxyethyl (meth)acrylate, norbornene (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, naphthalenyl (meth)acrylate, phenylphenol ethyl oxy (meth)acrylate, and the like.

[0015] Examples of the aromatic (meth)acrylate monomer include benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, ethoxylated o-phenylphenol acrylate, phenoxybenzyl (meth)acrylate, naphthalene (meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, modified bisphenol A di(meth)acrylate, and the like.

[0016] <<Radically polymerizable monomer (A2) having an OH group>> Component (A2) is a compound having a radically polymerizable group and an OH group. The number of OH groups possessed by component (A2) is preferably 1 to 3, and particularly preferably 1. The number of radically polymerizable groups possessed by component (A2) is preferably 1 to 2, and particularly preferably 1. Examples of component (A2) include hydroxyl group-containing (meth)acrylate monomers.

[0017] Examples of the hydroxyl group-containing (meth)acrylate monomer include hydroxyalkyl (meth)acrylates such as hydroxyethyl (meth)acrylate (e.g., 2-hydroxyethyl (meth)acrylate), hydroxypropyl (meth)acrylate (e.g., 2-hydroxypropyl (meth)acrylate), hydroxybutyl (meth)acrylate (e.g., 4-hydroxybutyl (meth)acrylate), and diethylene glycol monoethyl ether (meth)acrylate.

[0018] <<Difunctional or higher oligomers and difunctional or higher monomers (A3)>> The difunctional or higher oligomer and monomer (A3) refer to an oligomer and monomer having two or more radical polymerization reactive groups in the molecule. The oligomer having two or more radical polymerization reactive groups in the molecule includes a (meth)acrylate oligomer having two or more (meth)acryloyl groups in the molecule, and the (meth)acrylate oligomer is preferably a urethane (meth)acrylate oligomer, an epoxy (meth)acrylate oligomer, or the like.

[0019] The urethane (meth)acrylate oligomer may be an aromatic, aliphatic, polyether, polycarbonate, polyester, or combination thereof. In addition to those described in the examples, commercially available urethane (meth)acrylate oligomers include EBECRYL4858 (manufactured by Daicel-Allnex Corporation), UN-2301 (manufactured by Negami Chemical Industry Co., Ltd.), EBECRYL4859 (manufactured by Daicel-Allnex Corporation), and EBECRYL4738 (manufactured by Daicel-Allnex Corporation).

[0020] Epoxy (meth)acrylate oligomer is an oligomer in which all epoxy groups in the epoxy resin have reacted with (meth)acrylic acid. The epoxy (meth)acrylate oligomer may include an oligomer in which some epoxy groups in the epoxy resin have reacted with (meth)acrylic acid, that is, an oligomer having an epoxy group and a (meth)acryloyl group in the resin. Here, examples of the epoxy resin include aromatic epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, and other epoxy resins. Commercially available products of epoxy (meth)acrylate oligomer include EB3700 (manufactured by Daicel Ornex), EB3708 (manufactured by Daicel Ornex), and the like.

[0021] The number of (meth)acryloyl groups possessed by the (meth)acrylate oligomer may be 2 to 6, or may be 2 to 4.

[0022] Monomers having two or more radical polymerization reactive groups in the molecule can be appropriately selected from known components.

[0023] <<Radical Polymerization Reactive Components Other than Component (A1) to Component (A3)>> Examples of the radical polymerization reactive components other than component (A1) to component (A3) include a radical polymerization reactive monomer (A4) having a heterocyclic structure containing O and / or N, and other radical polymerization reactive components (A5).

[0024] <<Radical Polymerization Reactive Monomer (A4) Having a Heterocyclic Structure Containing O and / or N>> Component (A4) is a compound having a radical polymerization reactive group and a heterocyclic structure containing O and / or N. The heterocyclic structure possessed by component (A4) has one or more selected from the group consisting of an oxygen atom and a nitrogen atom as the heteroatoms constituting the ring structure.

[0025] When the heterocyclic structure contains an oxygen atom, the number of oxygen atoms contained in the heterocyclic structure is preferably 1 to 3, and more preferably 1 to 2. When the heterocyclic structure contains a nitrogen atom, the number of nitrogen atoms contained in the heterocyclic structure is preferably 1 to 2, and more preferably 1. When the heterocyclic structure contains both an oxygen atom and a nitrogen atom, the total number of oxygen atoms and nitrogen atoms contained in the heterocyclic structure is preferably 2 to 4, and more preferably 2 to 3.

[0026] The heterocyclic structure may be a monocyclic or polycyclic structure. The total number of atoms constituting one heterocyclic structure is not particularly limited, but is preferably 3 to 20. The heterocyclic structure is preferably a 5- or 6-membered monocyclic heterocyclic structure. Examples of the heterocyclic structure include morpholine, furan, tetrahydrofuran, dioxane, pyrrolidine, piperidine, piperazine, pyrrolidone, maleimide, etc.

[0027] The total number of heterocyclic structures contained in component (A4) is preferably 1 to 3, and particularly preferably 1 to 2. Here, when the heterocyclic structures are polycyclic structures, the polycyclic structures are counted as 1. Furthermore, the number of radical polymerization reactive groups contained in component (A4) is preferably 1 to 2, and particularly preferably 1. Component (A4) is preferably a (meth)acrylate monomer having a (meth)acryloyl group.

[0028] Specific examples of component (A4) include tetrahydrofurfuryl (meth)acrylate, alkoxylated tetrahydrofurfuryl acrylate, caprolactone-modified tetrahydrofurfuryl (meth)acrylate, morpholine (meth)acrylate (4-(meth)acryloylmorpholine, etc.), pentamethylpiperidinyl (meth)acrylate, and cyclic trimethylolpropane formal (meth)acrylate.

[0029] <<Other radical polymerization reactive components (A5)>> Component (A5) is a radical polymerization reactive component other than components (A1) to (A4). Component (A5) is preferably a (meth)acrylate monomer or oligomer having a (meth)acryloyl group. Examples of the (meth)acrylate monomer of component (A5) include an alkyl (meth)acrylate monomer and a (meth)acrylate of a (poly)alkylene glycol monoalkyl ether.

[0030] Examples of the alkyl (meth)acrylate monomer include methyl (meth)acrylate, ethyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, isomyristyl (meth)acrylate, and lauryl (meth)acrylate.

[0031] Examples of the (meth)acrylate monomer of the (poly)alkylene glycol monoalkyl ether include alkoxyethyl (meth)acrylate, alkoxypropyl (meth)acrylate, alkoxybutyl (meth)acrylate, and polymers of these alkylene glycols (e.g., methoxytriethyleneoxyethyl (meth)acrylate), etc. Here, the number of carbon atoms of the alkyl group, alkoxy group, and alkylene group is preferably 1 to 6.

[0032] The (meth)acrylate oligomer of component (A5) is not particularly limited as long as it is an oligomer having one (meth)acryloyl group in the molecule. The (meth)acrylate oligomer of component (A5) is the same as that described above for component (A3), except that the number of (meth)acryloyl groups in the molecule is one.

[0033] Component (A5) may be a combination of one or more of each of them. For example, component (A5) may be a combination of one or more of (meth)acrylate monomers and one or more of (meth)acrylate oligomers.

[0034] <Chain transfer agent (B)> The chain transfer agent (B) is a component that causes a chain transfer reaction. Here, the chain transfer reaction refers to a reaction in radical polymerization in which a propagating radical reacts with another chemical species in the polymerization system, resulting in the termination of propagation, the transfer of the radical, and the restart of propagation. Examples of component (B) include one or more selected from the group consisting of compounds having an α-methylstyrene structure, such as α-methylstyrene and α-methylstyrene dimer; alcohols, such as methanol, ethanol, propanol, and butanol; aldehydes, such as acetaldehyde, propionaldehyde, n-butylaldehyde, furfural, and benzaldehyde; halogens, such as carbon tetrachloride and chloroform; and compounds having a thiol group, such as pentaerythritol tetrakis(3-mercaptobutyrate), 1,4-bis(3-mercaptobutyryloxy)butane, dodecyl mercaptan, lauryl mercaptan, normal mercaptan, thioglycolic acid, octyl thioglycolate, and thioglycerol. Compounds having an α-methylstyrene structure or compounds having a thiol group are preferred. Component (B) may be one type or a combination of two or more types.

[0035] <Photopolymerization initiator (C)> The photopolymerization initiator (C) is not particularly limited as long as it is a compound that generates radicals by irradiation with energy rays. Component (C) is 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, benzophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone-1,2-hydroxy-2-methyl Oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], Oligo[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone], Benzoin methyl ether, Benzoin ethyl ether, Benzoin isobutyl ether, Benzoin isopropyl ether, Bis(2,4,6-trimethylbenzoyl)-phenylphosphine Oxide, oligo 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanol, oligo 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanol, 2-hydroxy-2-methyl-1-phenyl-1-propanone, isopropylthioxanthone, o-benzoylbenzoic acid methyl, [4-(methylphenylthio)phenyl]phenylmethane, 2,4-diethylthioxanthone, 2-chlorothioxanthone, benzophenone, ethyl anthraquinone, benzophenone anthraquinone monium salts, thioxanthone ammonium salts, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 4,4'-bisdiethylaminobenzophenone, 1,4 dibenzoylbenzene, 10-butyl-2-chloroacridone, 2,2'bis(o-chlorophenyl)4,5,4',5'-tetrakis(3,4,5-trimethoxyphenyl)1,2'-biimidazole, 2,2'bis(o-chlorophenyl)4,5,4',5'-tetraphenyl-1,2'-biimidazole, 4-benzoyldiphenyl ether, acrylated benzophenone, bis(η5-2,4-cyclopentadiene-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, o-methylbenzoyl benzoate, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ethyl ester, active tertiary amine, carbazole-phenone photopolymerization initiator, acridine photopolymerization initiator, triazine photopolymerization initiator, benzoyl photopolymerization initiator, etc.

[0036] Commercially available products of component (C) include KIP-150 manufactured by DKSH Japan, Omnirad® series such as Omnirad184, Omnirad819, Omnirad127, and Omnirad1173 manufactured by IGM Resins BV, Darocur® series such as Darocur1173, Lucirin® series such as Lucirin TPO, and ESACURE 1001M manufactured by ESACUR Nippon SiberHegner Co., Ltd. From the viewpoint of making the radical reaction of component (A) less susceptible to oxygen inhibition, which is a cause of non-curing, and further from the viewpoint of solubility in component (A) and alcohol-based cleaners, Omnirad1173 and Omnirad184 are preferred. Component (C) may be one type or a combination of two or more types.

[0037] <Additional Ingredients> The photocurable resin composition may contain additional components, if necessary, within the scope of not impairing the effects of the present invention. Examples of additional components include a polymer component (D), a thixotropic agent containing an inorganic substance, a silane coupling agent, a surfactant, a slip agent, a polymerization inhibitor, a photosensitizer, an antioxidant, a stabilizer, a colorant, a solvent, a filler, etc. Each of the additional components may be one component or a combination of two or more components.

[0038] The polymer component (D) is a component that adjusts the viscosity of the photocurable resin composition (for example, increases the viscosity of the photocurable resin composition). The component (D) is not particularly limited as long as it is a polymer that does not have a functional group reactive to radical polymerization and has the property of being dissolved in the photocurable resin composition. In addition, by selecting the component (D), a solvent capable of dissolving the composition can be selected. Examples of the component (D) include acrylic polymers such as poly(meth)acrylic acid, poly(meth)acrylic acid ester, or copolymers thereof; (hydrogenated) diene polymers such as polyisoprene, hydrogenated polyisoprene, polybutadiene, or hydrogenated polybutadiene. The (hydrogenated) diene polymer may be a homocopolymer of a conjugated diene monomer such as 1,3-butadiene or isoprene, or a copolymer of a conjugated diene monomer and an aromatic vinyl monomer such as styrene. The component (D) is preferably a high-viscosity liquid or solid having a viscosity of 100,000 mPa·s or more at 25°C, and particularly preferably a solid. In addition, component (D) preferably has a weight average molecular weight such that it is a high-viscosity liquid or solid of 100,000 mPa·s or more at 25°C. Here, the viscosity is a value measured using an E-type viscometer at atmospheric pressure and 25°C by selecting an appropriate cone plate and rotation speed. From the viewpoint of solubility in acetone, it is preferable that it is an acrylic polymer such as a copolymer of poly(meth)acrylic acid ester. From the viewpoint of solubility in methylcyclohexane, it is preferable that it is a (hydrogenated) diene polymer, and particularly preferable that it is a hydrogenated diene polymer.

[0039] The thixotropic agent containing an inorganic substance is not particularly limited as long as it has a high thickening or thixotropic effect with the addition of a small amount. Examples of the inorganic substance contained in the thixotropic agent include fumed silica, calcium carbonate, carbon black, kaolin, clay, activated clay, silica sand, silica stone, diatomaceous earth, anhydrous aluminum silicate, hydrated magnesium silicate, talc, perlite, white carbon, mica fine powder, bentonite, etc. In addition, the thixotropic agent may be composed of only an inorganic substance, or may be an inorganic substance surface-treated with a fatty acid and / or a resin acid.

[0040] The additional components other than the above-mentioned components are not particularly limited as long as they are components normally used in photocurable resin compositions, and can be appropriately selected depending on the purpose.

[0041] (Content of each ingredient) In the photocurable resin composition, the content of each component is as follows. In the component (A), the content of the radical polymerization reactive monomer (A1) having a cyclic structure not containing one or more atoms selected from O and N is preferably 40% by weight or more from the viewpoint of energy ray curability. The content of the component (A1) in the component (A) may be 100% by weight. In component (A), the content of the radical polymerization reactive monomer (A2) having an OH group is 0% by weight or more and less than 60% by weight. From the viewpoint of suppressing water absorption, the content of component (A2) in component (A) is preferably 0% by weight or more and 50% by weight or less, and particularly preferably 0% by weight or more and 40% by weight or less. In addition, from the viewpoint of energy ray curability, the content of component (A2) in component (A) is preferably 10% by weight or more and 40% by weight or less. In component (A), the content of difunctional or higher oligomer and difunctional or higher monomer (A3) is 0% by weight or more and less than 15% by weight. When the content of component (A3) in component (A) is 15% by weight or more, the solubility in at least one of acetone and methylcyclohexane after energy ray curing tends to be poor. In component (A), the content of the radical polymerization reactive monomer (A4) having a heterocyclic structure containing O and / or N is preferably 0% by weight or more and 60% by weight or less. From the viewpoint of obtaining a cured product with a lowered water absorption rate, the content of component (A4) in component (A) is more preferably 0% by weight or more and 50% by weight or less, and particularly preferably 0% by weight or more and 40% by weight or less. The content of component (A5) is the remainder after excluding components (A1) to (A4) in component (A), and is preferably less than 30% by weight from the viewpoint of energy ray curability.

[0042] From the viewpoint of achieving better solubility in at least one of acetone and methylcyclohexane after energy ray curing, the content of component (A1) in component (A) is preferably less than 100% by weight, and particularly preferably 50 to 90% by weight.

[0043] The content of component (A) as the main component of the photocurable resin composition is preferably 55% by weight or more, more preferably 70% by weight or more, and particularly preferably 80% by weight or more, in the photocurable resin composition.

[0044] The content of component (B) in the photocurable resin composition is preferably 0.5 to 10% by weight, more preferably 0.8 to 10% by weight, and particularly preferably 1.0 to 7.0% by weight, from the viewpoints of energy ray curability, water absorbency of the cured product, and solubility in at least one of acetone and methylcyclohexane after energy ray curing.

[0045] The content of component (C) in the photocurable resin composition is preferably 0.1 to 10% by weight, more preferably 0.5 to 8.0% by weight, and particularly preferably 1.0 to 7.0% by weight, from the viewpoints of energy ray curability and solubility in at least one of acetone and methylcyclohexane after energy ray curing.

[0046] From the viewpoint of superior solubility in at least one of acetone and methylcyclohexane after energy ray curing, the content of component (D) is preferably less than 50 parts by weight, more preferably 0 to 40 parts by weight, and particularly preferably 1 to 20 parts by weight, relative to 100 parts by weight of component (A). Furthermore, a photocurable resin composition in which the content of component (D) is 0 part by weight relative to 100 parts by weight of component (A) may be a composition that dissolves in acetone.

[0047] The content of the additional component other than the component (D) in the photocurable resin composition is preferably 20% by weight or less, more preferably 10% by weight or less, and particularly preferably 5.0% by weight or less. In addition, when the content of O or N etc. in the photocurable resin composition is high, the polarity tends to be high and the composition tends to be easily dissolved in acetone. On the other hand, when the content of hydrocarbon structures in the photocurable resin composition is high (i.e., when the content of O or N etc. is low), the polarity tends to be low and the composition tends to be easily dissolved in methylcyclohexane.

[0048] (Method for producing photocurable resin composition) The photocurable resin composition can be obtained by a production method including a step of mixing component (A), component (B), component (C), and an optional further component (such as component (D)).

[0049] (Method of curing photocurable resin composition) The photocurable resin composition can be cured by irradiation with energy rays. The energy rays and the like are as described later in the description of the temporary fixing material.

[0050] [Application] The photocurable resin composition can be used as a photocurable resin composition for temporary fixing (temporary fixing material), a photocurable resin composition for masking (masking material), or a photocurable resin composition for molding (molding material). Here, the photocurable resin composition is dissolved in at least one of acetone and methylcyclohexane in the above-mentioned application. Thus, the photocurable resin composition is used for dissolving in at least one of acetone and methylcyclohexane in the above-mentioned application. The photocurable resin composition can be applied to temporary fixing in the processing of quartz crystal oscillators, glass lenses, plastic lenses, and optical disks. In addition, the photocurable resin composition can be applied to masking of printed wiring boards, electronic parts, automobile parts, etc. In addition, the photocurable resin composition can be applied to molding materials such as pedestals for 3D printer printing.

[0051] (Temporary fixing material) The term "temporary fixation" refers to temporarily adhering one member to another member via a cured product of a photocurable resin composition. The cured product of the photocurable resin composition is later removed by dissolving it in at least one of acetone and methylcyclohexane, thereby losing the adhesiveness between the one member and the other member due to the cured product of the photocurable resin composition, thereby achieving the purpose of temporary fixation.

[0052] <Temporary fixing method> The method for temporarily fixing members using the photocurable resin composition for temporary fixation includes the steps of laminating substrates using the photocurable resin composition for temporary fixation, or overlapping two members and applying the photocurable resin composition to the outer periphery thereof, curing the photocurable resin composition for temporary fixation to bond and temporarily fix the substrates, processing the temporarily fixed substrates, and contacting the processed substrates with a cleaning agent which is at least one of acetone and methylcyclohexane, to remove the cured photocurable resin composition for temporary fixation.

[0053] Moreover, examples of a method for producing a processed body using a photocurable resin composition for temporary fixing include a method including the following steps (A) or (B) and (C) to (E). (A) (a1) a step of applying a photocurable resin composition to one substrate to form a photocurable resin composition layer, and (a2) a step of laminating another substrate onto the photocurable resin composition layer to obtain a laminate, or (B) a step of superposing one substrate on the other substrate, and then applying a photocurable resin composition to the peripheral edge or the superposed portion to obtain a laminate; (C) a step of irradiating the laminate obtained in step (A) or step (B) with energy rays to obtain a bonded body; (D) processing the bonded body to obtain a rough processed body; (E) A method of removing the cured product of the photocurable resin composition from the crude product to obtain a processed product.

[0054] Step (A) is comprised of step (a1) and step (b1). Step (a1) is a step of applying a photocurable resin composition to one of the substrates to form a photocurable resin composition layer. The material of the substrate is not particularly limited, but a substrate made of a material capable of transmitting ultraviolet light is preferred. Examples of such a material capable of transmitting ultraviolet light include quartz, glass, plastic, and the like.

[0055] The method of applying the photocurable resin composition to the substrate is not particularly limited, and examples thereof include inkjet printing (inkjet printing using an inkjet 3D printer), brush coating, screen printing, gravure printing, spraying, dipping, bar coater, roll coater, spin coater, die coater, dispenser, and other known coating means. The thickness of the curable resin composition layer formed by applying the photocurable resin composition is not particularly limited, but is preferably 10 to 500 μm, and particularly preferably 30 to 350 μm.

[0056] Step (a2) is a step of laminating another substrate on the photocurable resin composition layer to obtain a laminate. The other substrate is placed on the substrate on which the photocurable resin composition layer is formed so as to be in contact with the cured resin layer, and the substrates are laminated together to obtain a laminate. Step (a2) may include a step of subjecting the laminate to a pressure treatment.

[0057] Step (B) is a step of superposing one substrate on the other substrate, and then applying a photocurable resin composition to the outer peripheral edge or the overlapping portion to obtain a laminate. In step (B), the other substrate is placed on one substrate, and any condition may be used as long as the photocurable composition is applied so that the one substrate and the other substrate are fixed by the photocurable resin composition at the outer peripheral edge or the overlapping portion. Examples of the method of applying the photocurable resin composition include the methods described above in step (a1).

[0058] Step (C) is a step of obtaining an adhesive body by irradiating the laminate obtained in step (A) or step (B) with energy rays. By irradiating the laminate with energy rays, the photocurable resin composition between one substrate and the other substrate is cured, and the substrates are bonded to each other.

[0059] The energy ray is not particularly limited, and active energy rays such as visible light, ultraviolet light, X-rays, and electron beams can be used. The energy ray is preferably ultraviolet light. As a light source of ultraviolet light, a light source that emits ultraviolet light (UV) can be used. As a light source of ultraviolet light, for example, a metal halide lamp, a high-pressure mercury lamp, a xenon lamp, a mercury xenon lamp, a halogen lamp, a pulse xenon lamp, and an LED can be mentioned. The integrated light amount of the energy ray is, for example, 500 to 10,000 mJ / cm at 365 nm. 2 and preferably 1,000 to 8,000 mJ / cm 2 It is particularly preferred that:

[0060] Step (D) is a step of processing the bonded body to obtain a roughly processed body. Examples of processing include cutting, grinding, polishing, drilling, painting, etc. of the temporarily fixed bonded body into a desired shape, and are appropriately set depending on the processed body to be obtained.

[0061] Step (E) is a method of removing the cured product of the photocurable resin composition from the roughly processed body to obtain a processed body. The method of removing the cured product of the photocurable resin composition includes a method of contacting the roughly processed body with a cleaning agent, such as a method of spray-coating the cleaning agent on the cured product of the photocurable resin composition, and a method of immersing the roughly processed body in the cleaning agent. By the method of contacting the roughly processed body with the cleaning agent, the cured product of the photocurable resin composition is removed from the roughly processed body by peeling off from the substrate or dissolving.

[0062] The cleaning agent is at least one of acetone and methylcyclohexane, and can be appropriately selected depending on the type of photocurable resin composition.

[0063] The cleaning agent may further include a component that is usually added to an organic solvent-based cleaning agent, such as a surfactant. The surfactant may be a nonionic surfactant, an anionic surfactant, or a cationic surfactant. The surfactant may be one type or a combination of two or more types.

[0064] The temperature of the cleaner in step (E) is not particularly limited, and is preferably 25 to 70°C. The contact time between the roughly processed body and the cleaner in step (E) is not particularly limited as long as the cured product of the photocurable resin composition can be removed from the roughly processed body, and can be appropriately set by those skilled in the art. From the viewpoint of accelerating the dissolution of the cured product of the photocurable resin composition in the cleaner, it is preferable to vibrate the cleaner by ultrasonic waves or the like. The purpose of temporary fixation is achieved by step (E).

[0065] Examples of processed objects obtainable by the method for producing a processed object using a photocurable resin composition for temporary fixing include quartz crystal oscillators, glass lenses, plastic lenses, and optical disks.

[0066] (Masking material) Masking refers to the prevention of damage, adhesion of dirt, deterioration, etc. of a substrate by temporarily protecting the substrate with a cured product of a photocurable resin composition, or the prevention of film formation on wiring during a film formation process. The cured product of the photocurable resin composition is later removed, achieving the purpose of masking with the cured product of the photocurable resin composition. The photocurable resin composition can be used to temporarily mask substrates to be masked (e.g., printed wiring boards, electronic components).

[0067] <Masking method> As a method for masking a substrate, for example, a method of temporarily covering a part or the whole of a surface of a substrate with a cured product of a photocurable resin composition can be mentioned. When the substrate is handled or a plurality of substrates are stacked by the method for masking a substrate, the substrate is prevented from coming into direct contact with the substrate by the presence of a cured film between the substrates, and the substrate is prevented from being damaged, such as scratched, or from being attached with foreign matter. In addition, when painting an automobile part or the like, the paint can be prevented from splashing onto the unpainted region by temporarily covering the unpainted region with a cured film of a masking material.

[0068] Moreover, as a method for producing a processed body using the photocurable resin composition for masking, a method including the following steps (F) to (I) can be mentioned. (F) applying a photocurable resin composition to a substrate to form a photocurable resin composition layer; (G) a step of irradiating the photocurable resin composition layer with energy rays to obtain a substrate masked with a cured product of the photocurable resin composition; (H) a step of processing the substrate masked with the cured product of the photocurable resin composition to obtain a crude product; and (I) A step of removing the cured product of the photocurable resin composition from the crude product to obtain a processed product.

[0069] Examples of the method for applying the photocurable resin composition to a substrate, the method for curing the photocurable resin composition, the method for processing the substrate, and the method for removing the cured product of the photocurable resin composition include the methods described above in the method for manufacturing a processed body using the photocurable resin composition for temporary fixation.

[0070] Examples of processed articles that can be obtained by the method for producing a processed article using a photocurable resin composition for masking include electronic parts such as printed wiring boards and displays, and automobile parts.

[0071] (molding material) The photocurable resin composition can be used as a molding material (support material) such as a base for 3D printer printing. As a manufacturing method of a molded product using a 3D printer printing method, a method of curing 3D printer ink discharged from an inkjet nozzle of a 3D printer and stacking it to perform photolithography can be mentioned. Here, the 3D printer ink includes a model material that forms a molded body by photocuring with UV or the like, and a support material used as a support material when stacking the model material three-dimensionally. By stacking the model material on the molding material, it is possible to manufacture a molded product having a structure such as an overhang structure or a hollow structure.

[0072] A method for producing a molded article using a photocurable resin composition for molding includes the following steps (J) to (L). Here, steps (J) and (K) can be performed in any order or simultaneously depending on the shape of the molded article. (J) forming a molding material; (K) forming a model material; (L) A process for removing the molding material to obtain a molded product.

[0073] In the step of forming the molding material, the photocurable resin composition for molding is sprayed from the nozzle of a 3D printer (inkjet 3D printer), shaped by printing, etc., and then photocured to form the molding material. Examples of the method for curing the photocurable resin composition include the methods described above in the method for producing a processed body using the photocurable resin composition for temporary fixing.

[0074] In the process of forming the model material, the composition for the model material is modeled using a 3D printer, and then photocured to form the model material constituting the molded product. The composition for the model material can be appropriately set from known components, but is a composition that does not dissolve in a solvent that dissolves the molding material. The method for curing the model material can be appropriately set from known photocuring conditions.

[0075] In the molding material removal step, the method for removing the cured product of the photocurable resin composition described above in the manufacturing method of the processed body using the photocurable resin composition for temporary fixing can be mentioned. Here, the type of the cleaning agent used in the molding material removal step is at least one of acetone and methylcyclohexane, and can be appropriately selected depending on the type of the photocurable resin composition for molding. EXAMPLES

[0076] The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Values ​​in the tables are in parts by weight unless otherwise specified.

[0077] (Ingredients used) <Component (A): Radical polymerization reactive component> Component (A1): IBOA: Isobornyl acrylate (manufactured by Nippon Shokubai) Component (A1): FA-513AS: Dicyclopentanyl acrylate (manufactured by Showa Denko Materials) Component (A2): 4HBA: Hydroxybutyl acrylate (Osaka Organic Chemical Industry Co., Ltd.) Component (A3): UN-7700: Bifunctional urethane acrylate (manufactured by Negami Chemical Industries, Ltd.) Component (A4): THF-A: Tetrahydrofurfuryl acrylate (Showa Denko Materials) Ingredient (A5): LA: Lauryl acrylate (Kyoeisha Chemical) <Component (B): Chain transfer agent> Karenz MT PE1: Pentaerythritol tetrakis(3-mercaptobutyrate) (Showa Denko) Karenz MT BD1: 1,4-bis(3-mercaptobutyryloxy)butane (Showa Denko) MSD-100: α-methylstyrene dimer (Mitsui Chemicals) <Component (C): Photopolymerization initiator> Omnirad 1173: 2-hydroxy-2-methyl-1-phenyl-propan-1-one (manufactured by IGM Resins BV) <Component (D): Polymer component> LA1892: Acrylic polymer (Kuraray) (solid at 25°C) SEP2002: Styrene-hydrogenated isoprene copolymer (Kuraray) (solid at 25°C)

[0078] [Evaluation conditions] (1) UV curable (ultraviolet curable) The photocurable resin composition was poured into a mold measuring 20 × 5 × 1 mm, and then laminated with a PET (polyethylene terephthalate) film (Panasonic Corporation, product name Lumirror 100T60, thickness 100 μm). The film was then sandwiched between slide glasses, and 3000 mJ / cm of light with a wavelength of 365 nm was applied from a metal halide lamp (Eye Graphics Corporation, ECS-301). 2 The photocurable resin composition was cured by irradiation. After the PET film was removed, the photocurable resin composition was confirmed by touch with a finger whether it had been cured or not. ○: Cured (liquid (photocurable resin composition) does not come into contact with hands) △: Hardened but very sticky (liquid does not stick to hands) ×: Not cured (liquid gets on hands)

[0079] (2) Water absorption rate After measuring the weight of the test pieces whose UV curability was "○" or "△" in "(1) UV curability" above, they were placed in a 1 L beaker and about 100 g of water was poured in. The beaker was left to stand at room temperature (23°C) for 24 hours. After removing it from the water and wiping it thoroughly, the weight was measured again. The water absorption rate was calculated from the change in weight of the test piece before and after immersion in water using the following formula (1). A water absorption rate of less than 3.0% was considered particularly good, a rate of 3.0% or more but less than 5.0% was considered good, and a rate of 5.0% or more was considered poor. Water absorption rate (%) = (weight of test piece after immersion in water - weight of test piece before immersion in water) / weight of test piece before immersion in water × 100 Formula (1)

[0080] (3) Solvent solubility The test pieces that were graded as "○" or "△" in the above "(1) UV curability" were placed in a 1 L beaker, and about 100 g of acetone was poured in. The beaker was placed in an ultrasonic cleaner (US-20PS, manufactured by SND) and the weakest level of ultrasonic waves was applied for 5 minutes. After that, the test pieces were removed and visually confirmed whether any cured product of the photocurable resin composition remained. Those that did not dissolve in acetone were then subjected to the same test as above with 100 g of methylcyclohexane. ○1: No photocurable resin composition remains after acetone testing 〇2: No photocurable resin composition remains in the methylcyclohexane test ×: Photocurable resin composition remains in the test with acetone and methylcyclohexane

[0081] (4) Adhesion A spacer was placed on a slide glass substrate so that the thickness was 50 μm, and about 0.05 g of the photocurable resin composition was applied, and a PET film was attached from above. The irradiation was 3000 mJ / cm 2 using a metal halide lamp (M06-L31, manufactured by Eye Graphics). 2 After the UV irradiation, the PET film was peeled off and left for 24 hours, and then visually observed to confirm whether or not it had peeled off from the slide glass substrate. ○: No peeling ×: Peeling

[0082] [Production of photocurable resin composition] According to the compounding ratios shown in the table, components (A) to (C) and other components were mixed in a flask equipped with a stirrer for 30 minutes to 1 hour until homogenized. Among these, for Examples 18 and 19, components (A), (C) and (D) were stirred while being heated at 80°C to dissolve the solid components, and then component (B) was added to obtain liquid photocurable resin compositions of the Examples and Comparative Examples.

[0083] The results are shown in the table below. All values ​​of the amounts of each component are in parts by weight. The unit of water absorption is %.

[0084] [Table 1]

[0085] [Table 2]

[0086] [Table 3]

[0087] From Tables 1 and 2, the photocurable resin compositions of the Examples had excellent UV curability and excellent adhesion. The cured products of the photocurable resin compositions of the Examples had low water absorption. In addition, the photocurable resin compositions of the Examples had solubility in at least one of acetone and methylcyclohexane after UV curing. Therefore, the photocurable resin compositions can be used as photocurable resin compositions for temporary fixing, masking, or molding.

[0088] The results of Examples 2, 6 to 8, and Example 9 show that when component (A) contains component (A1) and component (A2), the UV curing property was superior when the content of component (A2) in component (A) was 10 to 40% by weight, and the water absorption rate was lower when the content of component (A2) was lower. Comparing Example 12 with Example 6 and the like, it was found that when the content of component (A5) in component (A) was less than 30% by weight, the UV curability was superior. The results of Examples 13 to 16 show that the water absorption rate decreased when the content of component (A4) was decreased. The results of Examples 6, 10 and 11 show that the water absorption rate was lower when the content of component (A3) was lower. A comparison between Example 18 and Example 19 showed that when the polymer component was an acrylic polymer, it was dissolved in acetone, and when the polymer component was a hydrogenated diene polymer, it was not dissolved in acetone but was dissolved in methylcyclohexane.

[0089] On the other hand, in Table 3, the composition of Comparative Example 1 did not contain component (B), and therefore the cured product of the photocurable resin composition of Comparative Example 1 had poor solubility in acetone and methylcyclohexane. The composition of Comparative Example 2 did not contain component (A1), and therefore had poor UV curability. The composition of Comparative Example 3 had a total content of di- or higher functional oligomers and monomers in component (A) of 20 wt%, and therefore the cured product of the photocurable resin composition of Comparative Example 3 had poor solubility in acetone and methylcyclohexane.

Claims

1. A photocurable resin composition for temporary fixing, masking, or molding, comprising: (A) a radical polymerization reactive component having a (meth)acryloyl group; (B) a chain transfer agent; and (C) a photopolymerization initiator, component (A) contains a (meth)acrylate monomer (A1) having a cyclic structure containing neither O nor N atoms and having one (meth)acryloyl group in the molecule, the content of component (A1) in component (A) being 40% by weight or more, In component (A), the content of the (meth)acrylate monomer (A2) having an OH group and one (meth)acryloyl group in the molecule is 10% by weight or more and 40% by weight or less, and the content of the (meth)acrylate oligomer having two or more (meth)acryloyl groups in the molecule and the (meth)acrylate monomer (A3) having two or more (meth)acryloyl groups in the molecule is 0% by weight or more and less than 15% by weight, The content of component (A) in the photocurable resin composition is 55% by weight or more, A photocurable resin composition for temporary fixing, masking or molding, characterized in that the content of component (B) in the photocurable resin composition is 1.0 to 10% by weight.

2. 2. The photocurable resin composition according to claim 1, wherein the content of the (meth)acrylate monomer (A4) having a heterocyclic structure containing O and / or N and having one (meth)acryloyl group in the molecule in the component (A) is 0% by weight or more and 50% by weight or less.

3. 3. The photocurable resin composition according to claim 1, wherein the component (B) is a compound having an α-methylstyrene structure or a compound having a thiol group.

4. The photocurable resin composition according to any one of claims 1 to 3, further comprising a polymer component (D).

5. The photocurable resin composition according to claim 4, wherein the component (D) is a hydrogenated diene-based polymer.

6. A photocurable resin composition for temporary fixing, masking or molding, comprising: (A) a radical polymerization reactive component having a (meth)acryloyl group; (B) a chain transfer agent; (C) a photopolymerization initiator; and (D) a polymer component, component (A) contains a (meth)acrylate monomer (A1) having a cyclic structure containing neither O nor N atoms and having one (meth)acryloyl group in the molecule, the content of component (A1) in component (A) being 40% by weight or more, In component (A), the content of a (meth)acrylate monomer (A2) having an OH group and one (meth)acryloyl group in the molecule is 0% by weight or more and 40% by weight or less, and the content of a (meth)acrylate oligomer having two or more (meth)acryloyl groups in the molecule and a (meth)acrylate monomer (A3) having two or more (meth)acryloyl groups in the molecule is 0% by weight or more and less than 15% by weight, The content of component (A) in the photocurable resin composition is 55% by weight or more, The content of component (B) in the photocurable resin composition is 1.0 to 10% by weight, A photocurable resin composition for temporary fixing, masking or molding, characterized in that component (D) is a hydrogenated diene polymer.

7. 7. The photocurable resin composition according to claim 6, wherein the content of the (meth)acrylate monomer (A4) having a heterocyclic structure containing O and / or N and having one (meth)acryloyl group in the molecule in the component (A) is 0% by weight or more and 60% by weight or less.

8. 8. The photocurable resin composition according to claim 6, wherein the component (B) is a compound having an α-methylstyrene structure or a compound having a thiol group.

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