Photocurable composition for support material formed by inkjet 3D printer and use thereof, and support material and optically built-up article production method using said photocurable composition

Abstract

The present invention addresses the problem of providing a photocurable composition capable of enhancing water solubility, support property, and transparency of a support material formed by an inkjet 3D printer. A photocurable composition for a support material formed by an ink jet 3D printer according to the present invention and solving said problem is characterized by containing a polymerizable monomer (A) having an oxyalkylene group and a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A).

Description

Photocurable composition for support material formed by inkjet 3D printer, use thereof, and method for producing support material and photo-fabricated object using said photocurable composition

[0001] The present invention relates to a photocurable composition for a support material formed by an inkjet 3D printer, use of the same, and a method for producing a support material and a stereolithography product using the photocurable composition.

[0002] In recent years, a stereolithography method using an inkjet 3D printer has been proposed, in which a liquid photocurable composition ejected from an inkjet nozzle is cured and layered to produce a shaped object. The inkjet 3D printer inks used in this stereolithography method include a photocurable composition for forming a molded body (model material) and a photocurable composition for forming a support material used to prevent the model material from collapsing when stacked three-dimensionally. By layering a photocured model material on the photocured support material and then removing the support material, it becomes possible to form overhanging structures, hollow structures, and the like.

[0003] Patent Document 1 describes a photocurable composition for a support material, which contains a water-soluble ethylenically unsaturated monomer containing an ionic group and a counter ion, and a photopolymerization initiator, and discloses that a support material formed from the composition has excellent water solubility and sufficient hardness (i.e., sufficient supportability).

[0004] Patent Document 2 describes a photocurable composition for a support material, which contains a water-soluble ethylenically unsaturated monomer containing an ionic group and a counter ion, and has a water content of 10 mass % or less relative to 100 mass % of the photocurable composition. It also discloses that the composition has excellent curability, and that a support material formed from the composition has sufficient hardness and excellent solubility in solvents.

[0005] International Publication No. WO 2018 / 043582 International Publication No. WO 2019 / 167948

[0006] Photocurable compositions for support materials formed by inkjet 3D printers are required to have better water solubility and supportability of the cured product after curing, as well as enhanced transparency of the cured product after curing. Therefore, an object of the present invention is to provide a photocurable composition that can enhance the water solubility, supportability, and transparency of the cured product (support material) formed by inkjet 3D printers.

[0007] As a result of intensive research to solve the above problems, the present inventors discovered that by using a photocurable composition containing a polymerizable monomer (A) having an oxyalkylene group and a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A), it is possible to improve the solubility in water, supportability, and transparency of a cured product (support material) formed by an inkjet 3D printer, and thus completed the present invention.

[0008] That is, the present invention is as follows. [1] A photocurable composition for a support material formed by an inkjet 3D printer, comprising a polymerizable monomer (A) having an oxyalkylene group and a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A). [2] The photocurable composition according to [1], wherein the polymerizable monomer (B) is an ionic monomer having an ionic group. [3] The photocurable composition according to [2], wherein the ionic monomer comprises an ionic monomer having a polyvalent metal ion that pairs with the ionic group. [4] The photocurable composition according to [3], wherein the content of the ionic monomer having a polyvalent metal ion is 50% by mass or more relative to 100% by mass of the polymerizable monomer (B). [5] The photocurable composition according to any one of [1] to [4], wherein the total content of the polymerizable monomer (A) and the polymerizable monomer (B) is less than 50% by mass relative to 100% by mass of the photocurable composition. [6] The photocurable composition according to any one of [1] to [5], wherein the polymerizable monomer (A) is a monomer represented by the following formula (1): Z-(R a -O) n -R b ...(1) [In formula (1), Z represents an ethylenically unsaturated bond-containing group, Ra represents an alkylene group, and R b represents a hydrogen atom or a hydrocarbon group which may have a substituent, and n represents an integer of 1 or more. When n is an integer of 2 or more, a plurality of R a may be the same or different.] [7] In the formula (1), Z is CH2=C(R 1 )-C(=O)-O-* or CH2=C(R 1 )-(CH2) m A group represented by —O—* (R 1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a substituent, m represents an integer of 0 to 6, and * represents a bond, a represents an alkylene group having 1 to 4 carbon atoms; R b represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 100. [8] The photocurable composition according to any one of [1] to [7], further comprising a photopolymerization initiator. [9] 100 mW / cm 2 The photocurable composition according to any one of [1] to [8], wherein when a cured piece (2 cm x 2 cm x 3 mm) obtained by irradiating the photocurable composition with light for 3 minutes is added to 50 mL of water at 25°C and allowed to stand for 3 hours, 50% by mass or more of the cured piece dissolves.

[10] A method for producing a support material, comprising irradiating the photocurable composition according to any one of [1] to [9] with light.

[11] A method for producing a stereolithographic object precursor, comprising: a step A of forming a support material layer by irradiating the photocurable composition according to any one of [1] to [9] with light; and a step B of forming a model material layer, which is carried out at the same and / or different timing as the step A, each repeated multiple times; and a step of removing the support material composed of the support material layer from the stereolithographic object precursor.

[12] Use of the photocurable composition according to any one of [1] to [9] for forming a support material using an inkjet 3D printer.

[13] A method for using the photocurable composition (I), comprising ejecting the photocurable composition (I) according to any one of [1] to [9] and a photocurable composition (II) different from the photocurable composition (I) from different ejection heads in an inkjet 3D printer.

[0009] According to the present invention, it is possible to provide a photocurable composition that can improve the water solubility, supportability, and transparency of a cured product (support material) formed using an inkjet 3D printer.

[0010] One embodiment of the present invention will be described below, but the present invention is not limited thereto. In this specification, unless otherwise specified, "A to B" representing a numerical range means "A or more and B or less." Furthermore, "(meth)acrylic acid" means acrylic acid or methacrylic acid, and "(meth)acrylate" means acrylate or methacrylate. The same applies to terms such as "(meth)acryloxy" and "(meth)acryloyl."

[0011] 1. Photocurable composition for support material formed by inkjet 3D printer The photocurable composition for support material formed by inkjet 3D printer of the present invention (hereinafter, may be simply referred to as "photocurable composition") contains a polymerizable monomer (A) having an oxyalkylene group and a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A). By including the polymerizable monomers (A) and (B) in the photocurable composition of the present invention, a support material with improved solubility in water, supportability, and transparency can be obtained.

[0012] The photocurable composition described below is used for forming a support material using an inkjet 3D printer. In other words, it is a composition for use in an inkjet 3D printer, and the photocurable composition may be used as is as an ink for an inkjet 3D printer, or may be a composition containing each component at a high concentration so that the photocurable composition can be used as an ink for an inkjet 3D printer by mixing the photocurable composition with a solvent at the time of use. Unless otherwise specified, the content of each component in the photocurable composition described below refers to the content in the photocurable composition when used as an ink for an inkjet 3D printer.

[0013] 1-1. Polymerizable Monomer (A) Having an Oxyalkylene Group The photocurable composition of the present invention contains a polymerizable monomer (A) having an oxyalkylene group. When the photocurable composition contains a polymerizable monomer (A) having an oxyalkylene group, the water solubility, supportability, and transparency of the resulting cured product (support material) tend to be improved, with transparency being particularly enhanced. In this specification, the term "polymerizable monomer" refers to a compound having one or more ethylenically unsaturated groups that polymerizes by light or the like.

[0014] The number of oxyalkylene groups in one molecule of the polymerizable monomer (A) is 1 or more, preferably 1 to 100, more preferably 2 to 80, even more preferably 4 to 60, and still more preferably 5 to 30.

[0015] The polymerizable monomer (A) is preferably a monomer represented by the following formula (1x), and more preferably a monomer represented by the following formula (1): Z-((R a -O) n -R b ) x ...(1x) Z-(R a -O) n -R b ...(1) [wherein Z represents an ethylenically unsaturated bond-containing group, R a represents an alkylene group, and R b represents a hydrogen atom or a hydrocarbon group which may have a substituent, n represents an integer of 1 or more, and x represents an integer of 1 to 4. When n or x is an integer of 2 or more, a plurality of R a and R b may be the same or different.

[0016] The ethylenically unsaturated bond-containing group represented by Z is a monovalent to tetravalent group having one or more ethylenically unsaturated bonds. The valence is determined by the R aWhen x is 1 in formula (1x), Z is a monovalent group, and when x is 2 in formula (1x), Z is a divalent group. In formula (1), Z is a monovalent group. The number of ethylenically unsaturated bonds contained in the ethylenically unsaturated bond-containing group is preferably 1 to 3, and more preferably 1.

[0017] The ethylenically unsaturated bond-containing group is preferably one having one ethylenically unsaturated group, for example, an alkene mono-, di-, tri-, or tetrayl group having about 2 to 10 carbon atoms, or a group in which the alkene mono-, di-, tri-, or tetrayl group is bonded to one or more divalent groups (carbonyl group, -O-, etc.). The ethylenically unsaturated bond-containing group having one ethylenically unsaturated group more preferably has an ethylenically unsaturated bond at a terminal, and is preferably a group having a structure such as CH═C(R 1 )-*, and more preferably has a group represented by CH2=C(R 1 )-C(=O)-O-* or CH2=C(R 1 )-(CH2) m It is even more preferable that the group is a group represented by —O—*, and CH═C(R 1 It is particularly preferable that R is a group represented by —C(═O)—O—*. 1 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms which may have a substituent, m represents an integer of 0 to 6, and * represents a bond.

[0018] The R 1 Specific examples of the alkyl group having 1 to 4 carbon atoms represented by the formula (I) include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

[0019] The R 1 The alkyl group having 1 to 4 carbon atoms represented by the formula (I) may have a substituent, and examples of the substituent include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, a hydroxy group, a thiol group, a group represented by *-C(=O)-R, a group represented by *-O-R, and a group represented by *-S-R. In addition, * represents a bond, and R represents a hydrocarbon group. Examples of the hydrocarbon group represented by R include the R groups described below.b Among them, an alkyl group or an aromatic hydrocarbon group is preferred, and an alkyl group having 1 to 4 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms is more preferred.

[0020] R 1 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group, and particularly preferably a hydrogen atom or a methyl group.

[0021] The above m is preferably an integer of 1 to 6, more preferably an integer of 1 to 4, and even more preferably 1 or 2.

[0022] Among these, the ethylenically unsaturated bond-containing group represented by Z includes a group represented by CH2=C(H)-C(=O)-O-*, a group represented by CH2=C(CH3)-C(=O)-O-*, a group represented by CH2=C(H)-(CH2) m1 A group represented by —O—*, or CH₂═C(CH₃)—(CH₂) m1 A group represented by —O—* (where m1 represents an integer of 1 to 4) is preferred.

[0023] In addition, from the viewpoint of further enhancing the transparency of the obtained cured product, it is preferable that Z in the above formula (1) is CH═C(R 1 In the above formula (1), Z is preferably a compound represented by CH2=C(R 1 The content of the compound which is a group represented by (III)-C(═O)-O-* is preferably 30% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and may be 100% by mass, based on 100% by mass of the polymerizable monomer (A).

[0024] R a The alkylene group represented by R may be linear or branched, but is preferably linear. a The number of carbon atoms in the alkylene group represented by R is preferably 1 to 6, more preferably 1 to 4, and even more preferably 2 or 3. aSpecific examples of the alkylene group represented by the formula (R) include linear alkylene groups such as methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene, and 1,6-hexylene; and branched alkylene groups such as 1,2-propylene, 1,2-butylene, 1,3-butylene, 2,3-butylene, and 1,2-hexylene. a The alkylene group represented by the formula (I) is preferably an alkylene group having 1 to 4 carbon atoms, more preferably a linear alkylene group having 1 to 4 carbon atoms, and even more preferably a linear alkylene group having 2 or 3 carbon atoms.

[0025] In the formula (1x) or (1), n ​​is an integer of 2 or more, and two or more kinds of R a In the case where the compound represented by formula (1x) or formula (1) contains an alkylene group represented by the formula:

[0026] R b The hydrocarbon group represented by the formula (I) may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or a group formed by combining these groups.

[0027] Examples of the aliphatic hydrocarbon group include: alkyl groups (preferably alkyl groups having 1 to 4 carbon atoms) such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl; alkenyl groups (preferably alkenyl groups having 2 to 6 carbon atoms) such as vinyl, n-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 1-pentenyl, 2-pentenyl, 2-methyl-1-butenyl, 2-methyl-2-butenyl, and 3-methyl-1-butenyl; and cycloalkyl groups (preferably cycloalkyl groups having 3 to 8 carbon atoms) such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 3-methylcyclohexyl, 4-methylcyclohexyl, and 4-ethylcyclohexyl. Among these, alkyl groups are preferred, more preferably alkyl groups having 1 to 4 carbon atoms, even more preferably methyl or ethyl, and particularly preferably methyl.

[0028] Examples of the aromatic hydrocarbon group include a phenyl group, a methylphenyl group, a dimethylphenyl group, a trimethylphenyl group, a 4-tert-butylphenyl group, and a naphthyl group, and preferably an aromatic hydrocarbon group having 6 to 10 carbon atoms.

[0029] Examples of the group formed by combining the aliphatic hydrocarbon group with the aromatic hydrocarbon group include aralkyl groups such as benzyl and phenethyl, and preferably aralkyl groups having 7 to 12 carbon atoms.

[0030] R b The hydrocarbon group represented by may have a substituent, and the substituent is R 1 The groups exemplified as the substituents that may be possessed by the alkyl group having 1 to 4 carbon atoms and represented by the following formula (I) are also included, and the preferred embodiments thereof are also the same.

[0031] R b is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, further preferably a hydrogen atom, a methyl group, or an ethyl group, and particularly preferably a hydrogen atom or a methyl group.

[0032] n is preferably an integer of 1 to 100, more preferably an integer of 2 to 80, even more preferably an integer of 4 to 60, and even more preferably an integer of 5 to 30. When the polymerizable monomer (A) is a mixture of monomers having different values ​​of n in the above formula (1), the above n can be an average value thereof.

[0033] The compound represented by the formula (1) may be a compound represented by the formula (1) in which Z is CH2=C(R 1 )-C(=O)-O-* or CH2=C(R 1 )-(CH2) m A group represented by —O—* (R 1 , m, and * are the same as above), and R a represents an alkylene group having 1 to 4 carbon atoms, and R b is preferably a compound in which Z is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 100; 2 )-C(=O)-O-* or CH2=C(R 2 )-(CH2) m2 A group represented by —O—* (R 2 represents a hydrogen atom or a methyl group, m2 represents an integer of 1 to 4, and * represents a bond, a represents an alkylene group having 2 or 3 carbon atoms, and R b More preferably, the compound is a compound in which n is an integer of 5 to 30 and represents a hydrogen atom or a methyl group.

[0034] Specific examples of the polymerizable monomer (A) include: (meth)acrylate compounds having an oxyethylene group, such as ethylene glycol (meth)acrylate, ethylene glycol methyl ether (meth)acrylate, polyethylene glycol (meth)acrylate having a repeat number of ethylene glycol (i.e., the repeat number of oxyethylene groups) of 2 to 100, and polyethylene glycol methyl ether (meth)acrylate having a repeat number of ethylene glycol (i.e., the repeat number of oxyethylene groups) of 2 to 100; (meth)acrylate compounds having an oxypropylene group, such as propylene glycol (meth)acrylate, propylene glycol monomethyl ether (meth)acrylate, polypropylene glycol (meth)acrylate having a repeat number of propylene glycol (i.e., the repeat number of oxypropylene groups) of 2 to 100, and polypropylene glycol monomethyl ether (meth)acrylate having a repeat number of propylene glycol (i.e., the repeat number of oxypropylene groups) of 2 to 100; Ethylene oxide adducts of unsaturated alcohols such as vinyl alcohol ethylene oxide (hereinafter EO) adducts (EO addition mole number 1 to 100 moles), (meth)allyl alcohol EO adducts (EO addition mole number 1 to 100 moles), 3-buten-1-ol EO adducts (EO addition mole number 1 to 100 moles), isoprene alcohol EO adducts (EO addition mole number 1 to 100 moles), 3-methyl-2-buten-1-ol EO adducts (EO addition mole number 1 to 100 moles), 2-methyl-3-buten-2-ol EO adducts (EO addition mole number 1 to 100 moles), 2-methyl-2-buten-1-ol EO adducts (EO addition mole number 1 to 100 moles), and 2-methyl-3-buten-1-ol EO adducts (EO addition mole number 1 to 100 moles);Examples include propylene oxide adducts of unsaturated alcohols such as vinyl alcohol propylene oxide (hereinafter referred to as PO) adducts (number of moles of PO added: 1 to 100 moles), (meth)allyl alcohol PO adducts (number of moles of PO added: 1 to 100 moles), 3-buten-1-ol PO adducts (number of moles of PO added: 1 to 100 moles), isoprene alcohol PO adducts (number of moles of PO added: 1 to 100 moles), 3-methyl-2-buten-1-ol PO adducts (number of moles of PO added: 1 to 100 moles), 2-methyl-3-buten-2-ol PO adducts (number of moles of PO added: 1 to 100 moles), 2-methyl-2-buten-1-ol PO adducts (number of moles of PO added: 1 to 100 moles), and 2-methyl-3-buten-1-ol PO adducts (number of moles of PO added: 1 to 100 moles);

[0035] Commercially available products can also be used as the polymerizable monomer (A), including NK Ester M-20G, M-40G, M-90G, M-130G, M-230G, M-450G, AM-90G, AM-130G, and AM-230G, manufactured by Shin-Nakamura Chemical Co., Ltd.; and Blenmar (registered trademark) PME-100, PME-200, PME-400, PME-1000, PME-4000, and AME-400, manufactured by NOF Corporation.

[0036] The photocurable composition of the present invention may contain one type of polymerizable monomer (A) alone or two or more types thereof.

[0037] In one preferred embodiment, two or more types of the polymerizable monomer (A) are used in combination.

[0038] When two or more kinds of polymerizable monomers (A) are used in combination, it is preferable to use polymerizable monomers (A) having different numbers of oxyalkylene groups in combination. The above-mentioned combination form may be, for example, a mixture of two or more kinds of polymerizable monomers (A) having adjacent numbers of oxyalkylene groups, such as a mixture of a polymerizable monomer (A) having 3 oxyalkylene groups, a polymerizable monomer (A) having 4 oxyalkylene groups, and a polymerizable monomer (A) having 5 oxyalkylene groups (for example, a mixture of compounds in formula (1x) or formula (1) where n is 3, 4, and 5), or may be a combination of two or more kinds of polymerizable monomers (A) having different average numbers of oxyalkylene groups, as described below.

[0039] In the photocurable composition of the present disclosure, the polymerizable monomer (A) preferably has a broad molecular weight distribution, preferably exhibiting a monomodal or polymodal molecular weight distribution, and more preferably exhibiting a monomodal or bimodal molecular weight distribution. The molecular weight distribution of the polymerizable monomer (A) can be measured by gel permeation chromatography (GPC), specifically under the same conditions as the method for measuring the weight average molecular weight of the polymerizable monomer (A) described below. In either form, the photocurable composition of the present invention tends to have excellent photocurability.

[0040] In an embodiment in which two or more polymerizable monomers (A) having different average numbers of oxyalkylene groups are used in combination as the polymerizable monomer (A), it is preferable to use two polymerizable monomers (A) having different average numbers of oxyalkylene groups in combination. That is, among embodiments in which the molecular weight distribution of the polymerizable monomer (A) exhibits a multimodal distribution, it is preferable that the molecular weight distribution of the polymerizable monomer (A) exhibits a bimodal distribution.

[0041] When two or more polymerizable monomers (A) having different average numbers of oxyalkylene groups are used in combination, the difference between the average number of oxyalkylene groups of the polymerizable monomer (A) having the largest average number of oxyalkylene groups and the average number of oxyalkylene groups of the polymerizable monomer (A) having the smallest average number of oxyalkylene groups is preferably 5 or more, more preferably 5 to 20. For example, a combination of a polymerizable monomer (A) having an average number of oxyalkylene groups of 1 to 5 with a polymerizable monomer (A) having an average number of oxyalkylene groups of 10 or more, or a combination of a polymerizable monomer (A) having an average number of oxyalkylene groups of 6 to 15 with a polymerizable monomer (A) having an average number of oxyalkylene groups of 20 or more is preferred, and a combination of a polymerizable monomer (A) having an average number of oxyalkylene groups of 1 to 5 with a polymerizable monomer (A) having an average number of oxyalkylene groups of 10 to 20, or a combination of a polymerizable monomer (A) having an average number of oxyalkylene groups of 10 to 15 with a polymerizable monomer (A) having an average number of oxyalkylene groups of 20 to 30 is more preferred.

[0042] When a polymerizable monomer (A) (hereinafter referred to as A1) having an average number of oxyalkylene groups of 1 to 5 is used in combination with a polymerizable monomer (A) (hereinafter referred to as A2) having an average number of oxyalkylene groups of 10 or more, the ratio (A1:A2) used is preferably 10:90 to 90:10, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40, by mass. When a polymerizable monomer (A) (hereinafter referred to as A3) having an average number of oxyalkylene groups of 6 to 15 is used in combination with a polymerizable monomer (A) (hereinafter referred to as A4) having an average number of oxyalkylene groups of 20 or more, the ratio (A3:A4) used is preferably 10:90 to 90:10, more preferably 30:70 to 70:30, and even more preferably 40:60 to 60:40, by mass.

[0043] When two or more polymerizable monomers (A) are used in combination, all of the ethylenically unsaturated bond-containing groups of the polymerizable monomers (A) are CH═C(R 1 )-C(=O)-O-*, or all are CH2=C(R 1 )-(CH2)m It is preferable that all of the groups are represented by —O—*, and 1 )-C(=O)-O-*, and it is even more preferable that all are groups represented by CH2=C(H)-C(=O)-O-* or all are groups represented by CH2=C(CH3)-C(=O)-O-*.

[0044] The weight average molecular weight of the polymerizable monomer (A) is not particularly limited, but is preferably 160 to 4,500.

[0045] The weight-average molecular weight of the polymerizable monomer (A) can be measured by gel permeation chromatography (GPC), specifically under the following conditions: Apparatus: High-speed GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation Detector: RI Column: SHODEX (registered trademark) Asahipak (registered trademark) GF-310-HQ, GF-710-HQ, GF-1G 7B manufactured by Showa Denko Column temperature: 40°C Flow rate: 0.5 ml / min Calibration curve: POLYACRYLIC ACID STANDARD manufactured by Sowa Scientific Co., Ltd. Eluent: 0.1 N aqueous sodium acetate solution / acetonitrile = 3 / 1 (weight ratio)

[0046] The content of the polymerizable monomer (A) is preferably 3 to 60% by mass, more preferably 5 to 45% by mass, and even more preferably 8 to 30% by mass, based on 100% by mass of the photocurable composition.

[0047] Furthermore, the content of the polymerizable monomer (A) relative to 100% by mass of the total amount of polymerizable monomers contained in the photocurable composition of the present invention (i.e., the total amount of polymerizable monomers (A) to (C)) is preferably 15 to 85% by mass, more preferably 25 to 75% by mass, and even more preferably 35 to 70% by mass. By adjusting the content of the polymerizable monomer (A) to be equal to or greater than the above-mentioned predetermined value, the transparency and water solubility of the obtained cured product tend to be further improved, and by adjusting the content of the polymerizable monomer (A) to be equal to or less than the above-mentioned predetermined value, the supportability of the obtained cured product tends to be further improved.

[0048] 1-2. Water-soluble polymerizable monomer (B) The photocurable composition of the present invention contains a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A). By including the polymerizable monomer (B), the curability of the photocurable composition is improved, and the supportability and water solubility of the resulting cured product are enhanced. The photocurable composition of the present invention may contain one type of polymerizable monomer (B) alone, or two or more types of polymerizable monomer (B). In this specification, the term "water-soluble polymerizable monomer" refers to a polymerizable monomer having a water solubility at 20°C (hereinafter referred to as water solubility (20°C)) of 20 g / L or more. In this specification, X g of polymerizable monomer (temperature: 20°C) is added to 50 cc of ion-exchanged water (temperature: 20°C) in a 100 cc screw tube in a constant temperature and humidity chamber at 20°C, and the solution is stirred for 5 minutes using a magnetic stirrer (rotor: 10 mm long x 4 mm diameter) and then allowed to stand for 10 minutes. When the resulting solution is visually inspected, if it becomes uniformly transparent, the water solubility (20°C) of the polymerizable monomer is judged to be Y g / L or more (Y = 20X). If the resulting solution does not become uniformly transparent, the water solubility (20°C) of the polymerizable monomer is judged to be less than Y g / L (Y = 20X). In other words, polymerizable monomer (B) can be said to be a polymerizable monomer that, when 1 g of polymerizable monomer is used in the measurement of the water solubility (20°C), gives a uniformly transparent solution. Note that "uniformly transparent" means that no phase separation or cloudiness is visually observed.

[0049] The water solubility (20° C.) of the polymerizable monomer (B) is preferably 100 g / L or more, more preferably 200 g / L or more, and even more preferably 500 g / L or more.

[0050] The content of the polymerizable monomer (B) is preferably 5 to 60% by mass, more preferably 8 to 40% by mass, and even more preferably 10 to 25% by mass, based on 100% by mass of the photocurable composition.

[0051] Furthermore, the content of the polymerizable monomer (B) relative to 100% by mass of the total amount of polymerizable monomers contained in the photocurable composition of the present invention (i.e., the total amount of polymerizable monomers (A) to (C)) is preferably 15 to 85% by mass, more preferably 25 to 75% by mass, and even more preferably 30 to 65% by mass. By adjusting the content of polymerizable monomer (B) to the above-mentioned predetermined value or more, the supportability of the obtained cured product can be further improved, and by adjusting the content of polymerizable monomer (B) to the above-mentioned predetermined value or less, the solubility in water of the obtained cured product can be further improved.

[0052] The mass ratio (B / A) of the polymerizable monomer (B) to the polymerizable monomer (A) is preferably 0.1 to 5.0, more preferably 0.3 to 3.0, and even more preferably 0.5 to 2.0. By adjusting the mass ratio (B / A) within the above range, the transparency and water solubility of the obtained cured product tend to be more excellent.

[0053] The polymerizable monomer (B) preferably contains an ionic monomer having an ionic group (hereinafter, may be simply referred to as an ionic monomer).

[0054] The ionic group includes anionic groups, and specific examples thereof include groups obtained by removing a proton from an acidic group such as a group obtained by removing a proton from a carboxy group, a group obtained by removing a proton from a phosphate group, and a group obtained by removing a proton from a sulfo group. Of these, the ionic group is preferably a group obtained by removing a proton from a carboxy group.

[0055] The ionic monomer preferably further has an ion that forms a pair with the ionic group (hereinafter, sometimes referred to as a counter ion). It is preferable that the ionic monomer is neutral as a whole, that is, the charges of the ionic group and the counter ion are balanced as a whole.

[0056] The counter ion is preferably a cation, and specific examples thereof include: monovalent counter ions such as alkali metal ions such as sodium ions and potassium ions, and ammonium ions; and polyvalent counter ions typified by polyvalent metal ions such as zinc ions, magnesium ions, calcium ions, aluminum ions, and neodymium ions.

[0057] In particular, from the viewpoint of further enhancing the supportability of the resulting cured product, the counter ion is preferably a polyvalent metal ion, i.e., the ionic monomer preferably contains an ionic monomer having a polyvalent metal ion that forms a pair with the ionic group (hereinafter, may be referred to as a polyvalent metal ion-containing ionic monomer). The counter ion constituting the polyvalent metal ion-containing ionic monomer is not particularly limited as long as it is a polyvalent metal ion, but among these, a divalent metal ion such as a zinc ion, a magnesium ion, a calcium ion, or a neodymium ion is preferred, with a zinc ion, a magnesium ion, or a calcium ion being more preferred, and a zinc ion being particularly preferred.

[0058] It is also preferable to use, as the ionic monomer, a polyvalent metal ion-containing ionic monomer in combination with an ionic monomer having a monovalent cation as the counter ion (hereinafter, sometimes referred to as a monovalent cation-containing ionic monomer). The counter ion constituting the monovalent cation-containing ionic monomer is preferably an alkali metal ion or ammonium, more preferably a sodium ion, potassium ion, or ammonium, and even more preferably a potassium ion.

[0059] The content of the ionic monomer (particularly, the total content of the monovalent cation-containing ionic monomer and the polyvalent metal ion-containing ionic monomer) is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 80 to 100 mass%, and particularly preferably 95 to 100 mass%, based on 100 mass% of the polymerizable monomer (B).

[0060] The content of the ionic monomer is preferably 5 to 60% by mass, more preferably 8 to 40% by mass, and even more preferably 10 to 25% by mass, based on 100% by mass of the photocurable composition.

[0061] Furthermore, the content of the ionic monomer relative to 100% by mass of the total amount of polymerizable monomers contained in the photocurable composition of the present invention (i.e., the total amount of polymerizable monomers (A) to (C)) is preferably 15 to 85% by mass, more preferably 25 to 75% by mass, and even more preferably 30 to 65% by mass. By adjusting the content of the ionic monomer to the above-mentioned predetermined value or more, the supportability of the obtained cured product can be further improved, and by adjusting the content of polymerizable monomer (B) to the above-mentioned predetermined value or less, the solubility in water of the obtained cured product can be further improved.

[0062] The content of the polyvalent metal ion-containing ionic monomer is, for example, 20 to 100% by mass, preferably 35% by mass or more, more preferably 50% by mass or more, even more preferably 65% ​​by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more, based on 100% by mass of the polymerizable monomer (B). Adjusting the content of the polyvalent metal ion-containing ionic monomer within the above range can further enhance the supportability of the resulting cured product. In particular, adjusting the content of the polyvalent metal ion-containing ionic monomer to 50% by mass or more tends to further enhance the effect of improving supportability. Furthermore, adjusting the content of the polyvalent metal ion-containing ionic monomer to 50% by mass or more (preferably 65% ​​by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more) can reduce the viscosity of the photocurable composition. Reducing the viscosity of the photocurable composition reduces the likelihood of ejection defects in inkjet 3D printers, such as clogging of the ejection head, thereby improving ejection stability.

[0063] The content of the monovalent cation-containing ionic monomer may be, for example, 10% by mass or more, or may be 20% by mass or more, relative to 100% by mass of the polymerizable monomer (B). The content of the monovalent cation-containing ionic monomer may be 100% by mass, relative to 100% by mass of the polymerizable monomer (B), but from the viewpoint of reducing the viscosity of the photocurable composition and further improving the supportability of the obtained cured product, the content is preferably 80% by mass or less, more preferably 50% by mass or less, even more preferably 35% by mass or less, still more preferably 20% by mass or less, particularly preferably 10% by mass or less, and may even be 0% by mass.

[0064] The mass ratio of the polyvalent metal ion-containing ionic monomer to the monovalent cation-containing ionic monomer contained in the photocurable composition (polyvalent metal ion-containing ionic monomer / monovalent cation-containing ionic monomer) is, for example, 20 / 80 to 100 / 0, preferably 35 / 65 to 100 / 0, more preferably 50 / 50 to 100 / 0, even more preferably 60 / 40 to 100 / 0, and particularly preferably 80 / 20 to 100 / 0. In particular, from the viewpoint of reducing the viscosity of the photocurable composition, the mass ratio is preferably adjusted to 50 / 50 to 100 / 0, more preferably 60 / 40 to 100 / 0, and even more preferably 80 / 20 to 100 / 0.

[0065] The ionic monomer containing a group obtained by removing a proton from a carboxyl group as the ionic group is preferably a salt of an ethylenically unsaturated carboxylic acid. Examples of the salt of the ethylenically unsaturated carboxylic acid include alkali metal salts such as sodium salts and potassium salts of the unsaturated carboxylic acid, monovalent salts such as ammonium salts, and polyvalent salts represented by polyvalent metal salts such as zinc salts, magnesium salts, calcium salts, aluminum salts, and neodymium salts. The ethylenically unsaturated carboxylic acid constituting the salt of the ethylenically unsaturated carboxylic acid is a carboxylic acid compound having an ethylenically unsaturated group, and specific examples thereof include aliphatic unsaturated carboxylic acids such as (meth)acrylic acid, maleic acid, fumaric acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxyethylsuccinic acid, N-(meth)acryloylaspartic acid, and ω-(meth)acroylalkane-1,1-dicarboxylic acid; and aromatic unsaturated carboxylic acids such as 2-(meth)acryloyloxybenzoic acid, 3-(meth)acryloyloxybenzoic acid, 4-(meth)acryloyloxybenzoic acid, 2-(meth)acryloyloxyethylphthalic acid, 2-vinylbenzoic acid, 3-vinylbenzoic acid, and 4-vinylbenzoic acid; and among these, aliphatic unsaturated carboxylic acids are preferred. The number of carbon atoms in the ethylenically unsaturated carboxylic acid constituting the salt of the ethylenically unsaturated carboxylic acid is preferably 3 to 15, more preferably 3 to 12, even more preferably 3 to 9, and particularly preferably 3 to 6. By using a salt of an ethylenically unsaturated carboxylic acid with a small number of carbon atoms, the hydrophobic portion in the molecule can be made smaller, and the solubility of the resulting cured product in water can be further increased.

[0066] The ionic monomer containing, as the ionic group, a group obtained by removing a proton from a phosphate group is preferably a salt of an ethylenically unsaturated phosphate. Examples of the salt of the ethylenically unsaturated phosphate include alkali metal salts such as sodium salts and potassium salts of ethylenically unsaturated phosphate, monovalent salts such as ammonium salts, and polyvalent salts represented by polyvalent metal salts such as zinc salts, magnesium salts, calcium salts, aluminum salts, and neodymium salts. The ethylenically unsaturated phosphoric acid constituting the salt of the ethylenically unsaturated phosphoric acid is a phosphoric acid compound having an ethylenically unsaturated group, and specific examples thereof include mono(2-(meth)acryloyloxyethyl) acid phosphate, phenyl(2-(meth)acryloyloxyethyl)phosphate, acid phosphooxyethyl (meth)acrylate, (meth)acryloyloxypropyl acid phosphate, (meth)acryloyloxy-2-hydroxypropyl acid phosphate, (meth)acryloyloxy-3-hydroxypropyl acid phosphate, (meth)acryloyloxy-3-chloro-2-hydroxypropyl acid phosphate, vinyl phosphoric acid, and p-vinylbenzene phosphoric acid.

[0067] The ionic monomer containing a group obtained by removing a proton from a sulfo group as the ionic group is preferably a salt of an ethylenically unsaturated sulfonic acid. Examples of the salt of an ethylenically unsaturated sulfonic acid include alkali metal salts such as sodium salts and potassium salts of ethylenically unsaturated sulfonic acid, monovalent salts such as ammonium salts, and polyvalent salts represented by polyvalent metal salts such as zinc salts, magnesium salts, calcium salts, aluminum salts, and neodymium salts. The ethylenically unsaturated sulfonic acid constituting the salt of an ethylenically unsaturated sulfonic acid is a sulfonic acid compound having an ethylenically unsaturated group, and specific examples thereof include allylsulfonic acid, isoprene sulfonic acid, 2-(meth)acrylamidoethylsulfonic acid, 3-(meth)acrylamidopropylsulfonic acid, 4-(meth)acrylamidobutylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, p-vinylbenzenesulfonic acid, and vinylsulfonic acid.

[0068] The ionic monomer is preferably a salt of an ethylenically unsaturated carboxylic acid, more preferably a monovalent salt and / or a polyvalent metal salt of an ethylenically unsaturated carboxylic acid, even more preferably a polyvalent metal salt of an ethylenically unsaturated carboxylic acid, even more preferably a divalent metal salt of an ethylenically unsaturated carboxylic acid such as a zinc salt, magnesium salt, calcium salt, or neodymium salt, particularly preferably a zinc salt, magnesium salt, or calcium salt of an ethylenically unsaturated carboxylic acid, and most preferably a zinc salt of an ethylenically unsaturated carboxylic acid. It is also preferable to use the polyvalent metal salt of an ethylenically unsaturated carboxylic acid in combination with a monovalent salt of an ethylenically unsaturated carboxylic acid. The monovalent salt of an ethylenically unsaturated carboxylic acid is preferably an alkali metal salt or ammonium salt of an ethylenically unsaturated carboxylic acid, more preferably a sodium salt, potassium salt, or ammonium salt of an ethylenically unsaturated carboxylic acid, and even more preferably a potassium salt of an ethylenically unsaturated carboxylic acid.

[0069] The ethylenically unsaturated carboxylic acid constituting the salt of the ethylenically unsaturated carboxylic acid is most preferably (meth)acrylic acid. That is, the ionic monomer is preferably a salt of (meth)acrylic acid, more preferably a monovalent salt and / or a polyvalent metal salt of (meth)acrylic acid, even more preferably a polyvalent metal salt of (meth)acrylic acid, even more preferably a divalent metal salt such as a zinc salt, magnesium salt, calcium salt, or neodymium salt of (meth)acrylic acid, particularly preferably a zinc salt, magnesium salt, or calcium salt of (meth)acrylic acid, most preferably a zinc salt of (meth)acrylic acid. It is also preferable to use the polyvalent metal salt of (meth)acrylic acid and a monovalent salt of (meth)acrylic acid in combination. The monovalent salt of (meth)acrylic acid is preferably an alkali metal salt or ammonium salt of (meth)acrylic acid, more preferably a sodium salt, potassium salt, or ammonium salt of (meth)acrylic acid, and even more preferably a potassium salt of (meth)acrylic acid.

[0070] The content of the salt of the ethylenically unsaturated carboxylic acid (particularly the salt of (meth)acrylic acid) is preferably 30 to 100 mass%, more preferably 50 to 100 mass%, even more preferably 80 to 100 mass%, and particularly preferably 90 to 100 mass%, based on 100 mass% of the polymerizable monomer (B).

[0071] The content of the salt of the ethylenically unsaturated carboxylic acid (particularly, the salt of (meth)acrylic acid) is preferably 5 to 60 mass%, more preferably 8 to 40 mass%, and even more preferably 10 to 25 mass%, based on 100 mass% of the photocurable composition.

[0072] Furthermore, the content of the salt of the ethylenically unsaturated carboxylic acid (particularly the salt of (meth)acrylic acid) relative to 100% by mass of the total amount of polymerizable monomers contained in the photocurable composition of the present invention (i.e., the total amount of polymerizable monomers (A) to (C)) is preferably 15 to 85% by mass, more preferably 25 to 75% by mass, and even more preferably 30 to 65% by mass. By adjusting the content of the salt of the ethylenically unsaturated carboxylic acid to the above-mentioned predetermined value or more, the supportability of the obtained cured product can be further improved, and by adjusting the content of the polymerizable monomer (B) to the above-mentioned predetermined value or less, the solubility in water of the obtained cured product can be further improved.

[0073] The content of the polyvalent metal salt of an ethylenically unsaturated carboxylic acid (particularly, a polyvalent metal salt of (meth)acrylic acid) is, for example, 20 to 100% by mass, preferably 35% by mass or more, more preferably 50% by mass or more, even more preferably 65% ​​by mass or more, and even more preferably 80% by mass or more, based on 100% by mass of the polymerizable monomer (B). By adjusting the content of the polyvalent metal salt of an ethylenically unsaturated carboxylic acid within the above range, the supportability of the resulting cured product can be further improved. In particular, by adjusting the content of the polyvalent metal salt of an ethylenically unsaturated carboxylic acid (particularly, a polyvalent metal salt of (meth)acrylic acid) to 50% by mass or more, the effect of improving supportability tends to be further enhanced. Furthermore, by adjusting the content of the polyvalent metal salt of an ethylenically unsaturated carboxylic acid (particularly, a polyvalent metal salt of (meth)acrylic acid) to 50% by mass or more (preferably 65% ​​by mass or more, more preferably 80% by mass or more), the viscosity of the photocurable composition can be reduced.

[0074] The content of the monovalent salt of the ethylenically unsaturated carboxylic acid (particularly, the monovalent salt of (meth)acrylic acid) may be, for example, 10% by mass or more, or may be 20% by mass or more, relative to 100% by mass of the polymerizable monomer (B). The content of the monovalent salt of the ethylenically unsaturated carboxylic acid (particularly, the monovalent salt of (meth)acrylic acid) may be 100% by mass, relative to 100% by mass of the polymerizable monomer (B). However, from the viewpoint of reducing the viscosity of the photocurable composition and further improving the supportability of the obtained cured product, the content is preferably 80% by mass or less, more preferably 50% by mass or less, even more preferably 35% by mass or less, still more preferably 20% by mass or less, particularly preferably 10% by mass or less, and may even be 0% by mass.

[0075] The mass ratio of the polyvalent metal salt of an ethylenically unsaturated carboxylic acid to the monovalent salt of an ethylenically unsaturated carboxylic acid (polyvalent metal salt of an ethylenically unsaturated carboxylic acid / monovalent salt of an ethylenically unsaturated carboxylic acid) contained in the photocurable composition is, for example, 20 / 80 to 100 / 0, preferably 35 / 65 to 100 / 0, more preferably 50 / 50 to 100 / 0, even more preferably 60 / 40 to 100 / 0, and particularly preferably 80 / 20 to 100 / 0. It is also preferable to adjust the mass ratio of the polyvalent metal salt of (meth)acrylic acid to the monovalent salt of (meth)acrylic acid (polyvalent metal salt of (meth)acrylic acid / monovalent salt of (meth)acrylic acid) contained in the photocurable composition to within the above range. In particular, from the viewpoint of reducing the viscosity of the photocurable composition, the mass ratio (i.e., polyvalent metal salt of ethylenically unsaturated carboxylic acid / monovalent salt of ethylenically unsaturated carboxylic acid, preferably polyvalent metal salt of (meth)acrylic acid / monovalent salt of (meth)acrylic acid) is preferably adjusted to 50 / 50 to 100 / 0, more preferably 60 / 40 to 100 / 0, and even more preferably 80 / 20 to 100 / 0.

[0076] Examples of the polymerizable monomer (B) other than the above ionic monomers include (meth)acrylic acid; methyl (meth)acrylate; (meth)acryloylmorpholine; N-vinylpyrrolidone; acrylamides such as (meth)acrylamide, N,N-dimethylacrylamide, N-hydroxyethylacrylamide, and N-isopropylacrylamide; and the like.

[0077] The total content of the polymerizable monomer (A) and the polymerizable monomer (B) relative to 100% by mass of the total amount of polymerizable monomers contained in the photocurable composition of the present invention (i.e., the total amount of the polymerizable monomers (A) to (C)) is preferably 50 to 100% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and particularly preferably 98% by mass or more.

[0078] 1-3. Polymerizable Monomer (C) The photocurable composition of the present invention may contain a polymerizable monomer (C) other than the polymerizable monomers (A) and (B) (for example, a polymerizable monomer having a water solubility (20°C) of less than 20 g / L). Examples of the polymerizable monomer (C) include ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, pentyl (meth)acrylate, isoamyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, isomyristyl (meth)acrylate, isostearyl (meth)acrylate, and n-stearyl (meth)acrylate. alkyl (meth)acrylates such as cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and other alicyclic hydrocarbon group-containing (meth)acrylates; aromatic hydrocarbon group-containing (meth)acrylates such as phenyl (meth)acrylate, benzyl (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate; and (meth)acrylate compounds such as tetrahydrofurfuryl (meth)acrylate. Examples of suitable vinyl ether compounds include allyl ether compounds such as phenyl allyl ether, o-, m-, p-cresol monoallyl ether, biphenyl-2-ol monoallyl ether, biphenyl-4-ol monoallyl ether, butyl allyl ether, cyclohexyl allyl ether, and cyclohexanemethanol monoallyl ether; vinyl ether compounds such as butyl vinyl ether, butyl propenyl ether, butyl butenyl ether, hexyl vinyl ether, ethylhexyl vinyl ether, phenyl vinyl ether, benzyl vinyl ether, acetylethoxyethoxy vinyl ether, cyclohexyl vinyl ether, and adamantyl vinyl ether; and maleimide compounds such as phenyl maleimide, cyclohexyl maleimide, and n-hexyl maleimide.These may be used alone or in combination of two or more.

[0079] The content of the polymerizable monomer (C) is preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably less than 2% by mass, based on 100% by mass of the photocurable composition. By adjusting the content of the polymerizable monomer (C) within the above range, the odor of the photocurable composition can be further suppressed.

[0080] The total content of the polymerizable monomer (A), polymerizable monomer (B), and polymerizable monomer (C) (particularly the total content of polymerizable monomers (A) and (B)) is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably less than 50% by mass, even more preferably 45% by mass or less, and particularly preferably 40% by mass or less, based on 100% by mass of the photocurable composition. By adjusting the total amount of polymerizable monomers (particularly the total content of polymerizable monomers (A) and (B)) within the above range, the viscosity of the photocurable composition can be reduced and the thermal stability of the photocurable composition (specifically, the effect of suppressing thickening when stored under high-temperature conditions) can be improved. Furthermore, the total content of the polymerizable monomer (A), polymerizable monomer (B), and polymerizable monomer (C) (particularly the total content of polymerizable monomers (A) and (B)) is preferably 8% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, based on 100% by mass of the photocurable composition. By adjusting the total amount of polymerizable monomers (particularly the total content of polymerizable monomers (A) and (B)) within the above range, the supportability of the obtained cured product can be further improved. That is, the total content of polymerizable monomer (A), polymerizable monomer (B), and polymerizable monomer (C) (particularly the total content of polymerizable monomers (A) and (B)) is preferably 8 to 80 mass%, more preferably 15 to 60 mass%, even more preferably 20 mass% or more but less than 50 mass%, still more preferably 20 to 45 mass%, and particularly preferably 20 to 40 mass%, relative to 100 mass% of the photocurable composition.

[0081] Increasing the proportion of the polyvalent metal ion-containing ionic monomer in the polymerizable monomer (B) can improve the supportability of the resulting cured product, even when the total amount of polymerizable monomers in the photocurable composition is at least. That is, from the viewpoint of achieving both the thermal stability of the photocurable composition and the supportability of the resulting cured product, an embodiment in which the total content of polymerizable monomer (A), polymerizable monomer (B), and polymerizable monomer (C) (particularly the total content of polymerizable monomers (A) and (B)) is 8% by mass or more but less than 50% by mass (preferably 15 to 45% by mass, more preferably 20 to 45% by mass, and even more preferably 20 to 40% by mass) of 100% by mass of the photocurable composition, and the content of the polyvalent metal ion-containing ionic monomer (preferably a polyvalent metal salt of an ethylenically unsaturated carboxylic acid, more preferably a polyvalent metal salt of (meth)acrylic acid) is 50 to 100% by mass of 100% by mass of polymerizable monomer (B) is preferred.

[0082] Furthermore, by increasing the proportion of the polyvalent metal ion-containing ionic monomer in the polymerizable monomer (B), the viscosity of the photocurable composition can be kept low even when the content of the polymerizable monomer in the photocurable composition is high. That is, even when the total content of the polymerizable monomer (A), polymerizable monomer (B), and polymerizable monomer (C) (particularly the total content of the polymerizable monomers (A) and (B)) is, for example, 15% by mass or more (preferably 20 to 45% by mass) based on 100% by mass of the photocurable composition, the viscosity of the photocurable composition can be kept low by adjusting the content of the polyvalent metal ion-containing ionic monomer (preferably a polyvalent metal salt of an ethylenically unsaturated carboxylic acid, more preferably a polyvalent metal salt of (meth)acrylic acid) to 50 to 100% by mass based on 100% by mass of the polymerizable monomer (B).

[0083] 1-4. Organic Acid and / or Salt Thereof The photocurable composition of the present invention may contain an organic acid and / or a salt thereof. By containing an organic acid and / or a salt thereof, storage stability is further improved. Note that the organic acid and / or a salt thereof is a compound that does not have a polymerizable unsaturated group, i.e., does not include the above-mentioned polymerizable monomers (A) to (C).

[0084] Examples of the organic acid include organic carboxylic acids, organic sulfonic acids, and organic phosphoric acids. Examples of the organic carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, octylic acid, nonanoic acid, decanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, tridecanoic acid, pentadecanoic acid, heptadecanoic acid, lactic acid, malic acid, citric acid, oxalic acid, malonic acid, succinic acid, fumaric acid, adipic acid, glycine, polyacrylic acid, and polylactic acid; and aromatic carboxylic acids such as benzoic acid, phthalic acid, and salicylic acid. Specific examples of the organic sulfonic acids include p-toluenesulfonic acid. Specific examples of the organic phosphoric acids include phenylphosphonic acid. Among these, organic carboxylic acids are preferred, aliphatic carboxylic acids are more preferred, and lactic acid, propionic acid, and polyacrylic acid are even more preferred.

[0085] The salt of the organic acid is preferably a metal salt of the organic acid, and specific examples thereof include alkali metal salts such as lithium salts, sodium salts, and potassium salts of the organic acid; alkaline earth metal salts such as magnesium salts, calcium salts, strontium salts, and barium salts of the organic acid; etc. Among these, alkali metal salts of the organic acid are preferred, and potassium salts of the organic acid are more preferred.

[0086] The photocurable composition of the present invention may contain one or more of these organic acids and / or salts thereof.

[0087] The organic acid and / or salt thereof is preferably an organic carboxylic acid or a metal salt of an organic carboxylic acid, more preferably an aliphatic carboxylic acid or a metal salt of an aliphatic carboxylic acid, and even more preferably lactic acid, a metal salt of lactic acid, propionic acid, a metal salt of propionic acid, polyacrylic acid, or a metal salt of polyacrylic acid.

[0088] The content of the organic acid and / or salt thereof is, for example, 0 to 20 mass% relative to 100 mass% of the photocurable composition, and from the viewpoint of enhancing storage stability in particular, it is preferably 0.1 to 20 mass%, more preferably 0.5 to 10 mass%, and even more preferably 1 to 5 mass%.

[0089] 1-5. Photopolymerization Initiator The photocurable composition of the present invention may contain a photopolymerization initiator. Specific examples of the photopolymerization initiator include: benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, and benzoin isobutyl ether; acetophenone compounds such as acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-methylpropanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one; anthraquinone compounds such as 2-ethylanthraquinone, 2-t-butylanthraquinone, 2-chloroanthraquinone, and 2-amylanthraquinone; Thioxanthone compounds such as 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2-chlorothioxanthone, and [3-(3,4-dimethyl-9-oxothioxanthen-2-yl)oxy-2-hydroxypropyl]-trimethylazanium chloride; ketal compounds such as acetophenone dimethyl ketal, benzil dimethyl ketal, and benzil diethyl ketal; benzophenone compounds such as benzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, and 4,4'-bismethylaminobenzophenone; phosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; and the like. These may be used alone or in combination of two or more.

[0090] Among these, the photopolymerization initiator is preferably a benzoin compound, an acetophenone compound, a ketal compound, or a phosphine oxide compound, α-hydroxyacetophenone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, and 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-methylpropanone; α-aminoacetophenone compounds such as 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one; benzil ketal compounds such as benzil dimethyl ketal and benzil diethyl ketal; and acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, with α-hydroxyacetophenone compounds being particularly preferred.

[0091] The content of the photopolymerization initiator is preferably 0.05 to 10.0% by mass, more preferably 0.1 to 7.0% by mass, and even more preferably 0.2 to 5.0% by mass, based on 100% by mass of the photocurable composition. By adjusting the content of the photopolymerization initiator within the above range, curability can be further improved. Furthermore, the content of the photopolymerization initiator is preferably 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and even more preferably 3.0 to 10 parts by mass, based on 100 parts by mass of the total of the polymerizable monomers (A) to (C) (particularly the total of the polymerizable monomer (A) and the polymerizable monomer (B)).

[0092] 1-6. Polymerization Inhibitor The photocurable composition of the present invention may contain a polymerization inhibitor to the extent that the effects of the present invention are not impaired. By containing a polymerization inhibitor, the thermal stability of the photocurable composition is improved.

[0093] Examples of the polymerization inhibitor include phenols with a molecular weight of less than 300, such as hydroquinone, catechol, resorcinol, p-methoxyphenol, t-butylcatechol, t-butylhydroquinone, pyrogallol, 2,4-dihydroxybenzophenone, 2,6-di-t-butyl-p-cresol, butylated hydroxyanisole, and 2,6-di-t-butyl-4-ethylphenol; 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), and 4,4'-thiobis(3 bisphenols such as 4,4'-(2,3-dimethyl-tetramethylene)dipyrocatechol, 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), 3,9-bis[1,1-dimethyl-2-[β-(3-t-butyl-4-hydroxy-5-methylphenyl)propionyloxy]ethyl]-2,4,8,10-tetraoxaspiro[5,5]undecane, and 4,4'-(2,3-dimethyl-tetramethylene)dipyrocatechol; stearyl-β-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, 3,4, 5-Trihydroxybenzoic acid propyl ester, 1,1,3-tris(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene (Irganox (registered trademark) 1330, manufactured by BASF), tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-t-butylphenyl)propionate]methane phenolic antioxidants such as polymeric phenols having a molecular weight of 300 or more, such as 1,3,5-tris(3',5'-di-t-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, tocopherol, tocopherol derivatives, and 2-[1-(2-hydroxy-3,5-di-tert-pentylphenyl)ethyl]-4,6-di-tert-pentylphenyl acrylate (Sumilizer (registered trademark) GS, manufactured by Sumitomo Chemical Co., Ltd.); 2-mercaptobenzimidazole, dilauryl 3,3'-thiodipropionate, dimyristyl 3,sulfur-based antioxidants such as 3'-thiodipropionate, distearyl 3,3'-thiodipropionate, 2-mercaptobenzimidazole, tetrakismethylene-3-(laurylthio)propionate methane, and stearylthiopropylamide; Triphenyl phosphite, diphenyl isodecyl phosphite, phenyl diisodecyl phosphite, 4,4'-butylidene-bis(3-methyl-6-t-butylphenylditridecyl)phosphite, cyclic neopentanetetraylbis(octadecyl)phosphite, tris(nonylphenyl)phosphite, tris(mono- and / or dinonylphenyl)phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-t-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10- phosphorus-based antioxidants such as methyl acrylate, 10-decyloxy-9,10-dihydro-9-oxa-10-phosphaphenanthrene, tris(2,4-di-t-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,4-di-t-butylphenyl)phosphite, cyclic neopentanetetraylbis(2,6-di-t-butyl-4-methylphenyl)phosphite, 2,2-methylenebis(4,6-di-t-butylphenyl)octylphosphite, distearyl pentaerythritol diphosphite, di(2,4-di-t-butylphenyl)phosphite, and tetrakis(2,4-di-t-butylphenyl)-4,4-biphenylenephosphonite; 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, bis(2,2,6,6-tetramethyl-4-piperidinyl)sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate, dimethyl succinate-1-(2-hydroxyethyl)-4-hydroxy-2,2,6,6-tetramethylpiperidine and its condensates, 8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4,5]decane-2,Examples of the antioxidant include hindered amine antioxidants such as 4-dione, alkoxyamine radicals such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, 1,1-diphenyl-2-picrylhydrazyl, phenothiazine, p-benzoquinone, nitrosobenzene, 2,5-di-t-butyl-p-benzoquinone, dithiobenzoyl disulfide, picric acid, cupferron, aluminum N-nitrosophenylhydroxylamine, tri-p-nitrophenylmethyl, N-(3-oxyanilino-1,3-dimethylbutylidene)aniline oxide, cyclohexanone oxime cresol, guaiacol, o-isopropylphenol, butyraldoxime, methyl ethyl ketoxime, and cyclohexanone oxime.

[0094] These polymerization inhibitors may be used alone or in combination of two or more.

[0095] The polymerization inhibitor is preferably at least one selected from the group consisting of a phenolic antioxidant, a sulfur-based antioxidant, a phosphorus-based antioxidant, a hindered amine-based antioxidant, and an alkoxyamine radical, and more preferably a phenolic antioxidant and / or an alkoxyamine radical. The total amount of the phenolic antioxidant, sulfur-based antioxidant, phosphorus-based antioxidant, hindered amine-based antioxidant, and alkoxyamine radical (preferably the total amount of the phenolic antioxidant and the alkoxyamine radical) in 100% by mass of the polymerization inhibitor is preferably 50 to 100% by mass, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0096] The content of the polymerization inhibitor is preferably 0.01 to 5.0% by mass, more preferably 0.03 to 3.0% by mass, and even more preferably 0.05 to 1.0% by mass, relative to 100 parts by mass of the total of the polymerizable monomers (A) to (C) (particularly, the total of the polymerizable monomer (A) and the polymerizable monomer (B)).

[0097] The photocurable composition of the present invention may contain a solvent as long as the effect of the present invention is not impaired. Examples of the solvent include water, monohydric alcohol, glycol, glycol ether, glycol ether acetate, and trihydric alcohol.

[0098] Specific examples of the monohydric alcohol include methanol, ethanol, and propanol, and preferred are monohydric alcohols having 1 to 5 carbon atoms.

[0099] Specific examples of the glycol include alkylene glycols such as ethylene glycol, propylene glycol, 1,3-butylene glycol, hexylene glycol, and 1,2-hexanediol (preferably C 2-6 alkylene glycol); polyalkylene glycols having a total number of repeating alkylene glycol units (i.e., the number of repeating oxyalkylene groups) of 2 or more (preferably 2 to 20, more preferably 2 to 10), such as diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, and copolymers of ethylene glycol and propylene glycol.

[0100] Specific examples of the glycol ether include propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monopropyl ether, and propylene glycol monopropyl ether. Of these, (poly)C 2-3 Alkylene glycol C 1-4 It is an alkyl ether.

[0101] Specific examples of the glycol ether acetate include propylene glycol monomethyl ether acetate and propylene glycol monoethyl ether acetate, and preferably (poly)C 2-3 Alkylene glycol mono C 1-4 It is an alkyl ether acetate.

[0102] Specific examples of the trihydric alcohol include glycerol.

[0103] The above solvents may be used alone or in combination of two or more.

[0104] The solvent preferably contains at least one selected from the group consisting of glycol, glycol ether, glycol ether acetate, and glycerol, more preferably at least one selected from the group consisting of glycol and glycerol, and particularly preferably contains glycol. The total content of glycol, glycol ether, glycol ether acetate, and glycerol (particularly the total content of glycol and glycerol) is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 95 to 100% by mass, based on 100% by mass of the solvent. The glycol content is preferably 50 to 100% by mass or more, more preferably 70 to 100% by mass, and even more preferably 90 to 100% by mass, based on 100% by mass of the solvent.

[0105] Among glycols, (poly)C glycols containing alkylene chains with 2 to 6 carbon atoms as the alkylene chains constituting the glycol molecule are preferred. 2-6 Alkylene glycols are preferred, and (poly)C 2-3 Alkylene glycol is more preferred, and (poly)propylene glycol containing an alkylene chain having 3 carbon atoms is even more preferred.

[0106] From the viewpoint of improving the thermal stability of the photocurable composition, the glycol should preferably contain at least C 2-6It preferably contains an alkylene glycol, more preferably contains at least ethylene glycol and / or propylene glycol, and even more preferably contains at least propylene glycol.

[0107] C 2-6 The content of alkylene glycol (particularly the content of propylene glycol) is preferably 20 to 100% by mass, more preferably 30 to 95% by mass, and even more preferably 40 to 90% by mass, based on 100% by mass of the solvent.

[0108] The glycols include C 2-6 Alkylene glycol and poly C 2-6 Preferably, the solvent contains an alkylene glycol; more preferably, it contains ethylene glycol and / or propylene glycol and polyethylene glycol and / or polypropylene glycol; even more preferably, it contains ethylene glycol and / or propylene glycol and a polyethylene glycol having an ethylene glycol repeat number (i.e., the number of oxyethylene group repeats) of 2 to 20 and / or a polypropylene glycol having a propylene glycol repeat number (i.e., the number of oxypropylene group repeats) of 2 to 20; and particularly preferably, it contains propylene glycol and a polyethylene glycol having an ethylene glycol repeat number (i.e., the number of oxyethylene group repeats) of 2 to 10 and / or a polypropylene glycol having a propylene glycol repeat number (i.e., the number of oxypropylene group repeats) of 2 to 10. The use of such glycols as a solvent improves the compatibility of the polymer obtained by curing the photocurable composition of the present invention with the solvent, possibly due to their good compatibility with the polymerizable monomer (A), thereby enhancing the transparency of the resulting support material. As a result, the surface properties of the resulting stereolithographic object tend to be improved.

[0109] C 2-6 Alkylene glycol and polyC 2-6 The total content of alkylene glycols is preferably 50 to 100% by mass or more, more preferably 70 to 100% by mass, and even more preferably 80 to 100% by mass, based on 100% by mass of the solvent.2-6 Poly C relative to 100 parts by mass of alkylene glycol 2-6 The content of alkylene glycol is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and even more preferably 20 to 120 parts by mass. In particular, it is preferable to adjust the total content of polyethylene glycol and polypropylene glycol to within the above range per 100 parts by mass of propylene glycol. In addition, the total content of polyC per 100 parts by mass of the polymerizable monomer (A) is preferably 5 to 200 parts by mass, more preferably 10 to 150 parts by mass, and even more preferably 20 to 120 parts by mass. 2-6 The content of alkylene glycol is preferably 10 to 500 parts by mass, more preferably 30 to 450 parts by mass, and even more preferably 50 to 400 parts by mass.

[0110] As described above, the solvent may contain water, but the content is preferably small. The water content is preferably 0 to 10% by mass, more preferably 5% by mass or less, and even more preferably 3% by mass or less, based on 100% by mass of the photocurable composition. By adjusting the water content within the above range, the supportability can be further improved. The water content in the photocurable composition can be calculated from the water content of each compound charged. It can also be determined by Karl Fischer measurement.

[0111] The total content of the solvents in 100% by mass of the photocurable composition of the present invention is preferably 20 to 90% by mass, more preferably 30 to 85% by mass, even more preferably 40 to 80% by mass, and still more preferably 50 to 80% by mass or 55 to 80% by mass.

[0112] 1-8. Other Additives The photocurable composition of the present invention may contain other additives as needed, as long as the effects of the present invention are not impaired. Examples of such additives include known additives such as photoinitiator aids, surfactants, colorants, chain transfer agents, fillers, emulsion stabilizers, penetration enhancers, UV absorbers, preservatives, antifungals, rust inhibitors, pH adjusters, surface tension adjusters, antifoaming agents, viscosity adjusters, dispersants, dispersion stabilizers, chelating agents, anti-drying agents (wetting agents), anti-fading agents, resistivity adjusters, and film modifiers.

[0113] Examples of the photoinitiator aid include tertiary amine compounds such as N,N-dimethylaniline, N,N-diethylaniline, N,N-dimethyl-p-toluidine, N,N-dimethylamino-p-benzoic acid ethyl ester, N,N-dimethylamino-p-benzoic acid isoamyl ethyl ester, N,N-dihydroxyethylaniline, triethylamine, and N,N-dimethylhexylamine.

[0114] Examples of surfactants include PEG-based nonionic surfactants such as 1-40 mole ethylene oxide (hereinafter abbreviated as EO) adducts of nonylphenol and 1-40 mole EO adducts of stearic acid; polyhydric alcohol-based nonionic surfactants such as sorbitan palmitate monoester, sorbitan stearate monoester, and sorbitan stearate triester; fluorine-containing surfactants such as 1-50 mole EO adducts of perfluoroalkyl, perfluoroalkyl carboxylates, and perfluoroalkyl betaines; and modified silicone oils such as polyether-modified silicone oils and (meth)acrylate-modified silicone oils.

[0115] Examples of colorants include toluidine red, permanent carmine FB, fast yellow G, disazo yellow AAA, disazo orange PMP, soluble azo pigments, condensed azo pigments, chelate azo pigments, phthalocyanine blue, indanthrone blue, quinacridone red, dioxazine violet, basic dyes, acid dyes, aniline black, daylight fluorescent pigments, nitroso pigments, nitro pigments, natural pigments, metal oxides as inorganic pigments, and carbon black.

[0116] Examples of the chain transfer agent include hydroquinone, diethylmethylamine, diphenylamine, diethyl disulfide, di-1-octyl disulfide, toluene, xylene, 1-butene, 1-nonene, dichloromethane, carbon tetrachloride, methanol, 1-butanol, ethyl thiol, 1-octyl thiol, acetone, methyl ethyl ketone, 2-methyl-2-propyl aldehyde, 1-pentyl aldehyde, phenol, m-cresol, p-cresol, and o-cresol.

[0117] Examples of fillers include alumina powder, silica powder, talc, mica, clay, aluminum hydroxide, calcium carbonate, calcium silicate, aluminum powder, copper powder, carbon fiber, glass fiber, cotton fiber, nylon fiber, acrylic fiber, rayon fiber, microballoons, carbon black, metal sulfides, and wood flour.

[0118] The additives may be used alone or in combination of two or more. The content of the additives may be adjusted appropriately depending on the additives used, but is preferably 0 to 30% by mass, more preferably 0.05 to 20% by mass, and even more preferably 0.05 to 10% by mass or 0.05 to 5% by mass, relative to 100% by mass of the photocurable composition.

[0119] 1-9. Method for Preparing Photocurable Composition The photocurable composition of the present invention can be prepared using the various components described above, and the preparation means and conditions are not particularly limited, but examples include a method of stirring and mixing using a mixing or stirring device such as a general stirring blade or ultrasonic homogenizer, high-speed homogenizer, high-pressure homogenizer, planetary stirring device, three-roll mill, ball mill, Kitty mill, disk mill, pin mill, or Dyno mill. The mixture obtained by stirring and mixing may be filtered using various filters.

[0120] 1-10. Physical Properties of the Photocurable Composition The photocurable composition of the present invention preferably has a viscosity of 20 mPa·s or less at the discharge temperature, from the viewpoint of improving dischargeability from the discharge head of an inkjet 3D printer. Furthermore, from the viewpoint of discharge stability, the photocurable composition of the present invention preferably has a low viscosity at 25°C, specifically 300 mPa·s or less, more preferably 200 mPa·s or less, even more preferably 150 mPa·s or less, and particularly preferably 100 mPa·s or less. The lower limit is not particularly limited, but is, for example, 5 mPa·s or more, preferably 20 mPa·s or more. The viscosity of the photocurable composition can be measured in accordance with JIS Z 8803 using an E-type viscometer.

[0121] The photocurable composition of the present invention preferably has a surface tension of 25 to 70 mN / m at 25° C. The surface tension of the photocurable composition can be measured, for example, using a bubble pressure type dynamic surface tensiometer BP100 (manufactured by KRUSS).

[0122] The photocurable composition of the present invention has excellent curability. 2 It is preferable that the composition be cured by irradiating it with ultraviolet light of 1000 kJ / cm 2 or more. Here, "cured" means that the composition is no longer in a liquid state and loses its fluidity.

[0123] The cured product obtained using the photocurable composition of the present invention has excellent supportability. Here, supportability refers to the ability of the cured product obtained by curing the photocurable composition to support a model material. The higher the hardness of the cured product obtained by curing the photocurable composition, the higher the supportability. When the photocurable composition of the present invention is exposed to a light of 100 mW / cm 2 When the hardness of a plate-shaped cured product (thickness: 3 mm) obtained by irradiating the product with ultraviolet light for 3 minutes is measured using a Type E durometer, the hardness 0 seconds after the start of measurement is preferably 65 or more, more preferably 75 or more, even more preferably 80 or more, and particularly preferably 85 or more or more.

[0124] The cured product formed from the photocurable composition of the present invention preferably has the property of being easily removable with water. 2 When a cured product piece (2 cm × 2 cm × 3 mm thick) obtained by irradiating the cured product piece with UV light for 3 minutes is added to 50 mL of water at 25°C and allowed to stand for 3 hours, preferably 50 mass % or more of the cured product piece dissolves, more preferably 80 mass % or more of the cured product piece dissolves, and particularly preferably all of the cured product piece dissolves.

[0125] The cured product formed from the photocurable composition of the present invention has excellent transparency. The inventors have discovered that the better the transparency of the cured product formed from the photocurable composition for a support material (specifically, the lower the haze of the cured product), the cleaner (less rough) the surface state of the resulting photofabricated object (model material). Although the mechanism behind this is unclear, when the support material is made of a photocurable composition in which a highly water-soluble polymerizable monomer is dissolved or dispersed (i.e., a water-affinity photocurable composition) and the model material is made of a photocurable composition in which a less water-soluble polymerizable monomer is dissolved or dispersed (i.e., a water-incompatible photocurable composition), the better the transparency of the cured product (support material) formed from the water-affinity photocurable composition for a support material, the more difficult it becomes for the photocurable composition for a support material to mix with the water-incompatible photocurable composition for a model material. As a result, when both the photocurable composition for a support material and the photocurable composition for a model material are ejected, the separation of their interfaces is enhanced, resulting in a photofabricated object (model material) with a clean surface derived from the interface. The photocurable composition of the present invention was exposed to 100 mW / cm 2 When the haze of a plate-shaped piece of the cured product (thickness: 2 mm) obtained by irradiating the cured product with ultraviolet light of 1000 W for 3 minutes is measured using a turbidity meter, the haze is preferably 70% or less, more preferably 50% or less, even more preferably 10% or less, and particularly preferably less than 5%.

[0126] 2. Cartridge for Inkjet 3D Printer The photocurable composition is used as an ink for an inkjet 3D printer. The photocurable composition is usually filled into a cartridge for an inkjet 3D printer for use. The inkjet 3D printer cartridge may be filled with the photocurable composition, and any known inkjet 3D printer cartridge may be used.

[0127] 3. Method for Producing Support Material The support material of the present invention is produced by irradiating the photocurable composition with light. That is, the method for producing a support material of the present invention only needs to include a step of irradiating the photocurable composition with light. Specifically, it preferably includes a step of ejecting the photocurable composition from the ejection head of an inkjet 3D printer (ejection step a) and a support material layer formation step A, which includes a step of irradiating the ejected photocurable composition with light (light irradiation step a). By repeatedly performing this support material layer formation step A, support material layers can be stacked, and a support material of the desired shape can be produced. In the ejection step a, a known method can be used other than using the photocurable composition.

[0128] The light to be irradiated onto the photocurable composition may be ultraviolet light, near ultraviolet light, visible light, infrared light, far infrared light, electron beam, α-rays, γ-rays, X-rays, or the like, with ultraviolet light being preferred.

[0129] The exposure dose during light irradiation was 100 mJ / cm 2 ~3000mJ / cm 2 is preferred, and more preferably 100 to 2000 mJ / cm 2 , more preferably 100 to 1000 mJ / cm 2 is.

[0130] 4. Manufacturing Method of a Photo-Fabricated Object The manufacturing method of a photo-fabricated object of the present invention includes a step of forming a modeled object precursor, in which a step A of forming a support material layer by irradiating the photocurable composition with light and a step B of forming a model material layer are each repeated multiple times, and a step of removing the support material composed of the support material layer from the photo-fabricated object precursor.

[0131] In the method for producing a photo-fabricated object, known methods can be used, except that the above-mentioned photocurable composition (hereinafter sometimes referred to as photocurable composition (I)) is used in the support material layer formation step A. Specifically, the support material layer formation step A preferably includes a step of ejecting the photocurable composition (I) from the ejection head of an inkjet 3D printer (ejection step a) and a step of irradiating the ejected photocurable composition (I) with light (light irradiation step a). By repeatedly performing this support material layer formation step A, support material layers can be stacked, and a support material of the desired shape can be produced. Preferred aspects of the ejection step a and light irradiation step a are the same as those described above.

[0132] The model material layer formation step B preferably includes a step of irradiating a photocurable composition for the model material (hereinafter sometimes referred to as photocurable composition (II)) with light. Specifically, it preferably includes a step of ejecting the photocurable composition (II) from the ejection head of the inkjet 3D printer (ejection step b) and a step of irradiating the ejected photocurable composition (II) with light (light irradiation step b). By repeatedly performing this model material layer formation step B, model material layers can be stacked to produce a model material with the desired shape.

[0133] The ejection step b in the model material layer formation step B is a step of ejecting the photocurable composition (II) from the ejection head of the inkjet 3D printer. In the ejection step b, a known method can be used.

[0134] It is preferable that the ejection head that ejects the photocurable composition (I) in the ejection step a is different from the ejection head that ejects the photocurable composition (II) in the ejection step b. That is, the inkjet 3D printer used in the present invention preferably includes an ejection head for ejecting the photocurable composition (I) and an ejection head for ejecting the photocurable composition (II).

[0135] The light irradiation step b in the model material layer formation step B is a step of irradiating the photocurable composition (II) discharged in the discharge step b with light, and a known method can be used. Preferred aspects of the light irradiation step b are the same as those of the light irradiation step a.

[0136] A stereolithography precursor composed of a supporting material and a modeling material is produced by repeating the forming step A and the forming step B multiple times. Specifically, the stereolithography precursor can be produced by stacking layers obtained by dividing the target stereolithography precursor into thin flakes. Examples of the layers include a layer consisting only of a supporting material, a layer consisting only of a modeling material, and a layer consisting of a supporting material and a modeling material (i.e., a layer in which the supporting material and the modeling material are present on the same plane). To form a layer consisting only of a supporting material, the forming step A is carried out. To form a layer consisting only of a modeling material, the forming step B is carried out. To form a layer consisting of a supporting material and a modeling material, the forming step A and the forming step B are carried out simultaneously. By appropriately repeating these steps, the target stereolithography precursor can be produced. The order and number of repetitions of the forming step A, the forming step B, and the simultaneous carrying out of the forming step A and the forming step B can be adjusted appropriately depending on the shape of the target stereolithography precursor.

[0137] When the forming step A and the forming step B are performed simultaneously, it is preferable to first perform the discharging step a and the discharging step b, thereby placing the photocurable composition (I) and the photocurable composition (II) on the same plane, and then perform the light irradiation step a and the light irradiation step b. In this case, the discharging step a and the discharging step b may be performed simultaneously, or may be performed at different times, such as performing the discharging step a after the discharging step b, or performing the discharging step a after the discharging step b. In the present invention, a photocurable composition for the support material (i.e., the photocurable composition (I)) is used that has an enhanced transparency for the resulting cured product, so the interfacial separability between the photocurable composition (I) and the photocurable composition (II) discharged by the discharging step a and the discharging step b is enhanced. Furthermore, the light irradiation step a and the light irradiation step b can be performed while this interfacial separability is enhanced, so a photo-molded object (model material) with a clean surface derived from the interface can be obtained. When the forming step A of the support material layer and the forming step B of the model material layer are performed simultaneously, it is more preferable to perform the light irradiation step a and the light irradiation step b simultaneously.

[0138] The photocurable composition (II) used in the formation step B is preferably a composition containing a polymerizable monomer (D) and a photopolymerization initiator.

[0139] The polymerizable monomer (D) is not particularly limited as long as it is a compound having one or more ethylenically unsaturated groups and is polymerizable by light or the like, and specifically includes: (meth)acrylic acid; alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, isobutyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, and t-butyl (meth)acrylate; hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate; Alicyclic hydrocarbon group-containing (meth)acrylates such as cyclohexyl (meth)acrylate, 4-t-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, and adamantyl (meth)acrylate; aromatic hydrocarbon group-containing (meth)acrylates such as phenyl (meth)acrylate and phenoxyethyl (meth)acrylate; heterocycle-containing (meth)acrylates such as tetrahydrofurfuryl (meth)acrylate, 4-(meth)acryloyloxymethyl-2-methyl-2-ethyl-1,3-dioxolane, 4-(meth)acryloyloxymethyl-2-cyclohexyl-1,3-dioxolane, cyclic trimethylolpropane formal (meth)acrylate, and glycidyl (meth)acrylate; Alkyleneoxy group-containing (meth)acrylates such as tripropylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 2-n-butyl-2-ethyl-1,3-propanediol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and 2-(2-vinyloxyethoxy)ethyl (meth)acrylate; (meth)acrylamides such as N-alkyl(meth)acrylamides having an alkyl group having 1 to 12 carbon atoms introduced therein;Vinyl compounds such as vinyl acetate, vinyl propionate, methyl vinyl ether, styrene, and N-vinyl caprolactam; allyloxymethyl methyl acrylate; and the like.

[0140] The polymerizable monomer (D) may be used alone or in combination of two or more thereof. The polymerizable monomer (D) is preferably a monomer that does not contain a metal component, and more preferably does not contain the above-mentioned polymerizable monomer (A) or polymerizable monomer (B) (particularly, an ionic monomer).

[0141] The polymerizable monomer (D) preferably contains a polymerizable monomer having a water solubility (20° C.) of less than 20 g / L, more preferably a polymerizable monomer having a water solubility (20° C.) of 10 g / L or less, and even more preferably a polymerizable monomer having a water solubility (20° C.) of 1 g / L or less. From the viewpoint of preventing the resulting cured product (model material) from dissolving in water, the content of the polymerizable monomer having a water solubility (20° C.) of less than 20 g / L (preferably 10 g / L or less, more preferably 1 g / L or less) is preferably 50 to 100 mass%, more preferably 60 to 100 mass%, based on 100 mass% of the polymerizable monomer (D).

[0142] From the viewpoint of improving the curability of the photocurable composition (II), the content of the polymerizable monomer (D) is preferably 15 to 90 mass%, and more preferably 20 to 80 mass%, relative to 100 mass% of the photocurable composition (II).

[0143] As the photopolymerization initiator contained in the photocurable composition (II), the compounds exemplified as the photopolymerization initiator in the photocurable composition (I) can be used.

[0144] The content of the photopolymerization initiator is preferably 0.05 to 10.0% by mass, more preferably 0.1 to 7.0% by mass, and even more preferably 0.2 to 5.0% by mass, based on 100% by mass of the photocurable composition (II). By adjusting the content of the photopolymerization initiator within the above range, curability can be further improved. Furthermore, the content of the photopolymerization initiator is preferably 0.5 to 20 parts by mass, more preferably 1.0 to 15 parts by mass, and even more preferably 3.0 to 10 parts by mass, based on 100 parts by mass of the polymerizable monomer (D).

[0145] The photocurable composition (II) may further contain a solvent. Examples of the solvent that can be used include those exemplified as the solvent for the photocurable composition (I). The content of the solvent is not particularly limited, and may be adjusted so that the photocurable composition (II) has a suitable viscosity. The photocurable composition (II) preferably has a viscosity of 5 to 300 mPa·s at 25°C. Furthermore, from the viewpoint of improving the ejection properties from the ejection head of an inkjet 3D printer, the viscosity of the photocurable composition (II) at the ejection temperature is preferably 20 mPa·s or less.

[0146] The photocurable composition (II) may contain other additives as needed, as long as the effects of the present invention are not impaired. Examples of the additives include known additives such as a photoinitiator aid, a polymerization inhibitor, a surfactant, a colorant, a chain transfer agent, a filler, an emulsion stabilizer, a penetration enhancer, an ultraviolet absorber, an antiseptic, an antifungal agent, an antirust agent, a pH adjuster, a surface tension adjuster, an antifoaming agent, a viscosity adjuster, a dispersant, a dispersion stabilizer, a chelating agent, an anti-drying agent (wetting agent), an anti-fading agent, a resistivity adjuster, and a film adjuster.

[0147] The model material formed from the photocurable composition (II) must be resistant to the support material removal process. 2 When a piece of the cured product (2 cm x 2 cm x 3 mm) obtained by irradiating the cured product with ultraviolet light of 1000 W for 3 minutes is added to 50 mL of water at 25°C and allowed to stand for 3 hours, it is preferable that the piece of the cured product does not dissolve at all.

[0148] Subsequently, a step of removing the support material composed of the support material layer from the obtained stereolithography precursor is carried out, thereby obtaining the desired stereolithography product (a stereolithography product composed of a model material). The support material can be easily removed using a polar solvent such as water, alcohol, an acidic solution, or a basic solution. From the viewpoints of safety and reducing environmental impact, it is preferable to use water as the polar solvent. In terms of safety and cost, the support material removal step is preferably a method in which the stereolithography precursor is allowed to stand in a polar solvent (preferably water) to remove the support material. The standing time is not particularly limited, but from the viewpoint of workability, it is preferably 1 to 5 hours, more preferably 0.5 to 2 hours. In addition, the temperature of the polar solvent (preferably water) is preferably 10 to 40°C, more preferably 20 to 30°C.

[0149] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples, and can of course be practiced with appropriate modifications within the scope of the above and below-described aims, all of which are included within the technical scope of the present invention. In the following, unless otherwise specified, "parts" means "parts by mass" and "%" means "% by mass."

[0150] Example 1 To a 20 mL brown screw tube were added 20 parts of methoxypolyethylene glycol acrylate (average number of repeating oxyethylene groups: approximately 9, product name "NK Ester AM-90G" manufactured by Shin-Nakamura Chemical Co., Ltd.), 15 parts of zinc acrylate, 30 parts of propylene glycol, 30 parts of triethylene glycol, 5 parts of glycerin, and 2 parts of a photopolymerization initiator (product name "Omnirad2959" manufactured by IGM Resins B.V.), and the mixture was stirred and mixed to obtain a photocurable composition.

[0151] Examples 2 to 13, Comparative Examples 1 to 3 Photocurable compositions were obtained in the same manner as in Example 1, except that the compositions were changed as shown in Table 1.

[0152] The photocurable compositions obtained in the examples and comparative examples were evaluated by the following evaluation methods.

[0153] (1) Evaluation of Viscosity of Photocurable Composition The viscosity of the photocurable compositions of Examples 11 to 13 was measured at 25° C. using a TPE100 viscometer (manufactured by Toki Sangyo Co., Ltd.) according to a method in accordance with JIS Z 8803. The obtained viscosities (unit: mPa s) are shown in Table 1.

[0154] (2) Evaluation of curability The photocurable composition was irradiated with 100 mW / cm 2 The appearance of the light-irradiated object (2 cm x 2 cm x 3 mm thick) obtained by irradiating the object with ultraviolet light (wavelength 365 nm) for 30 seconds was visually inspected and evaluated. The evaluation criteria are as follows. The results are shown in Table 1. ○: The light-irradiated object did not flow, i.e., it was hardened. ×: The light-irradiated object was a liquid or viscous liquid and had flowability.

[0155] (3) Evaluation of supportability: The photocurable composition was subjected to 100 mW / cm 2 The hardness of the cured product (2 cm x 2 cm x 3 mm thick) obtained by irradiating it with ultraviolet light (wavelength 365 nm) for 3 minutes was measured and evaluated using a Type E Durometer (manufactured by Kobunshi Keiki Co., Ltd.) at 0 seconds after the start of measurement. The evaluation criteria are as follows. The results are shown in Table 1. ◯: Over 85 △: 65 to 85 ×: Less than 65

[0156] (4) Evaluation of Transparency: The photocurable composition was irradiated with 100 mW / cm 2 The haze of a cured product piece (6 cm x 3 cm x 2 mm) obtained by irradiating the cured product with ultraviolet light (wavelength 365 nm) for 3 minutes was measured using a turbidity meter (Nippon Denshoku Industries Co., Ltd., Haze Meter NDH7000). The evaluation criteria are as follows. The results are shown in Table 1. ○: Haze less than 5% △: Haze 5% to 50% ×: Haze more than 50%

[0157] (5) Evaluation of water solubility: The photocurable composition was subjected to 100 mW / cm 2 A piece of cured material (2 cm x 2 cm x 3 mm thick) obtained by irradiating with ultraviolet light (wavelength 365 nm) for 3 minutes was placed on a wire net and kept in 50 mL of water at 25°C, and the time until the cured material piece was completely dissolved was measured. The evaluation criteria are as follows. The results are shown in Table 1. ◯: Less than 3 hours ×: 3 hours or more

[0158]

[0159] Details of each component listed in Table 1 are as follows. AM-90G: methoxypolyethylene glycol acrylate (average number of repeating oxyethylene groups: approximately 9), manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester AM-90G" AM-130G: methoxypolyethylene glycol acrylate (average number of repeating oxyethylene groups: approximately 13), manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester AM-130G" AM-230G: methoxypolyethylene glycol acrylate (average number of repeating oxyethylene groups: approximately 23), manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester AM-230G" M-90G: methoxypolyethylene glycol methacrylate (average number of repeating oxyethylene groups: approximately 9), manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester M-90G" M-130G: methoxypolyethylene glycol methacrylate (average number of repeating oxyethylene groups: approximately 13), manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester M-130G" M-230G: methoxypolyethylene glycol methacrylate (average number of repeating oxyethylene groups: approximately 23), manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "NK Ester M-230G" Viscoat #MTG: methoxytriethylene glycol acrylate, manufactured by Osaka Organic Chemical Industry, Ltd., trade name "Viscoat #MTG" Polyethylene glycol 400: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Polyethylene Glycol 400" Polypropylene glycol (diol type, Mn=400): manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Polypropylene Glycol, Diol Type, 400" Omnirad 2959 (trade name): 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-methylpropanone (acetophenone-type photopolymerization initiator), manufactured by IGM Resins B.V.

[0160] The photocurable resin compositions of the examples containing a polymerizable monomer (A) having an oxyalkylene group and a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A) were excellent in curability as shown in Table 1, and cured products (support materials) with improved supportability, transparency, and solubility in water were obtained.

Claims

1. A photocurable composition for a support material formed by an inkjet 3D printer, comprising a polymerizable monomer (A) having an oxyalkylene group and a water-soluble polymerizable monomer (B) other than the polymerizable monomer (A).

2. The photocurable composition according to claim 1, wherein the polymerizable monomer (B) is an ionic monomer having an ionic group.

3. The photocurable composition according to claim 2, wherein the ionic monomer contains an ionic monomer having a polyvalent metal ion that pairs with the ionic group.

4. The photocurable composition according to claim 3, wherein the content of the ionic monomer having a polyvalent metal ion is 50% by mass or more in 100% by mass of the polymerizable monomer (B).

5. The photocurable composition according to claim 1, wherein the total content of the polymerizable monomer (A) and the polymerizable monomer (B) is less than 50% by mass in 100% by mass of the photocurable composition.

6. The photocurable composition according to claim 1, wherein the polymerizable monomer (A) is a monomer represented by the following formula (1). Z-(R a -O) n -R b …(1) [In formula (1), Z represents an ethylenically unsaturated bond-containing group, R a represents an alkylene group, R b represents a hydrogen atom or a hydrocarbon group which may have a substituent, and n represents an integer of 1 or more. When n is an integer of 2 or more, a plurality of R a may be the same or different from each other.] 7. In the formula (1), Z is CH2═C(R 1 )−C(═O)−O−* or CH2═C(R 1 )(CH2) m −O−* (where R 1 represents a hydrogen atom or an optionally substituted alkyl group having 1 to 4 carbon atoms, m represents an integer of 0 to 6, and * represents a bond), R a represents an alkylene group having 1 to 4 carbon atoms, R b represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and n represents an integer of 1 to 100. The photocurable composition according to claim 6.

8. The photocurable composition according to claim 1, further comprising a photoinitiator.

9. 100 mW / cm 2 The photocurable composition according to claim 1, wherein when a cured piece (2 cm × 2 cm × 3 mm) obtained by irradiating light of 2 for 3 minutes is added to 50 mL of water at 25°C and allowed to stand for 3 hours, 50% by mass or more of the cured piece dissolves.

10. A method for manufacturing a support material, comprising irradiating light on the photocurable composition according to any one of claims 1 to 9.

11. A forming step A of a support material layer by irradiating light on the photocurable composition according to any one of claims 1 to 9, and a forming step B of a model material layer performed at the same and / or different timing as the forming step A, each being repeated a plurality of times to form a photocurable object precursor, and a step of removing the support material composed of the support material layer from the photocurable object precursor. A method for manufacturing a photocurable object.

12. Use of the photocurable composition according to any one of claims 1 to 9 for forming a support material by an inkjet 3D printer.

13. A method for using the photocurable composition (I) according to any one of claims 1 to 9, wherein the photocurable composition (I) and a photocurable composition (II) different from the photocurable composition (I) are ejected from different ejection heads in an inkjet 3D printer.

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