Curable resin composition for photofabrication, cured object, and three-dimensional fabricated object

Abstract

Provided are: a curable resin composition from which a three-dimensional fabricated object having both excellent heat resistance and excellent flame retardancy can be produced; a cured object formed from the composition; and a three-dimensional fabricated object comprising the cured object.　A curable resin composition for photofabrication according to the present invention comprises: one or more polymerizable monomers including a photopolymerizable monomer (A) having two or more photopolymerizable functional groups; a phosphorus-based flame retardant (B); and a photopolymerization initiator. A homopolymer of the photopolymerizable monomer (A) preferably has a glass transition temperature of 100°C or higher. The phosphorus-based flame retardant (B) is preferably a flame retardant based on an aromatic phosphoric acid ester. The phosphorus-based flame retardant (B) preferably has a liquid form at 23°C. The phosphorus-based flame retardant (B) is contained preferably in an amount of 15-45 parts by weight per 100 parts by weight of the polymerizable monomers. The polymerizable monomers preferably further include a urethane oligomer (C) having two or more urethane bonds per molecule.

Description

Curable resin composition for stereolithography, cured product, and three-dimensional object

[0001] The present invention relates to a curable resin composition for stereolithography, a cured product of the composition, and a three-dimensional object made of the cured product.

[0002] In recent years, optical 3D modeling (stereolithography) has been used as a method for producing resin molded products. This method involves selectively polymerizing and curing a curable resin composition with active energy rays, such as an ultraviolet laser, based on three-dimensional shape data designed using a three-dimensional design system, such as 3D CAD, to produce a three-dimensional object. Because optical 3D modeling can handle complex shapes that are difficult to produce using cutting, has a short production time, and is easy to handle, it has come to be widely used for the production of not only resin molded products but also prototype models of industrial products. Accordingly, various curable resin compositions containing polymerizable monomers used in optical 3D modeling have been developed.

[0003] Curable resin compositions used in such optical three-dimensional modeling methods are required not only to be capable of three-dimensional modeling, but also to provide heat resistance and flame retardancy to the three-dimensionally modeled objects, particularly for electric and electronic components, automobile components, furniture, home appliance components, etc. As a method for imparting such heat resistance and flame retardancy, for example, a method using a polymerizable composition containing a liquid photopolymerizable compound, a flame retardant, and a flame retardant protective agent, as disclosed in Patent Document 1 below, is known.

[0004] International Publication No. 2019 / 203134

[0005] The present inventors have studied the above-mentioned Patent Document 1 and found that there is a problem in that the concentration of reactive functional groups in the polymerizable composition is low, and sufficient heat resistance cannot be achieved in the presence of a flame retardant. Furthermore, they found that the inclusion of a flame retardant protecting agent causes problems such as a decrease in the molecular weight of the polymer due to inhibition of UV curing, and the protecting agent itself acts as a plasticizer, causing a decrease in the heat resistance of the three-dimensionally shaped object.

[0006] Therefore, the problem to be solved by the present invention is to provide a curable resin composition capable of producing a three-dimensional object having excellent heat resistance and flame retardancy, a cured product of the composition, and a three-dimensional object made of the cured product.

[0007] As a result of intensive research to solve the above problems, the inventors discovered that the above problems can be solved by using a curable resin composition for stereolithography containing a specific photopolymerizable monomer and a phosphorus-based flame retardant, and thus completed the present invention.

[0008] That is, the present invention encompasses the following aspects. [1] A curable resin composition for stereolithography, comprising a polymerizable monomer including a photopolymerizable monomer (A) having two or more photopolymerizable functional groups, a phosphorus-based flame retardant (B), and a photopolymerization initiator. [2] The curable resin composition for stereolithography according to [1], wherein a homopolymer of the photopolymerizable monomer (A) has a glass transition temperature (Tg) of 100°C or higher. [3] The curable resin composition for stereolithography according to [1] or [2], wherein the phosphorus-based flame retardant (B) is an aromatic phosphate ester-based flame retardant. [4] The curable resin composition for stereolithography according to any one of [1] to [3], wherein the phosphorus-based flame retardant (B) is liquid at 23°C. [5] The curable resin composition for stereolithography according to any one of [1] to [4], wherein the phosphorus-based flame retardant (B) is 15 to 45 parts by weight per 100 parts by weight of the polymerizable monomer. [6] The curable resin composition for stereolithography according to any one of [1] to [5], further comprising a urethane oligomer (C) having two or more urethane bonds per molecule as the polymerizable monomer. [7] The curable resin composition for stereolithography according to [6], wherein the urethane oligomer (C) has three or more (meth)acryloyl groups per molecule. [8] The curable resin composition for stereolithography according to [6] or [7], wherein either the photopolymerizable monomer (A) or the urethane oligomer (C), or both, have an isocyanuric acid skeleton. [9] The curable resin composition for stereolithography according to any one of [1] to [8], which is used in a digital light processing 3D printer.

[10] The curable resin composition for stereolithography according to any one of [6] to [9], wherein the content of the urethane oligomer (C) is 10 to 55 wt % based on the total amount of the polymerizable monomer and the urethane oligomer (C).

[11] The curable resin composition for stereolithography according to any one of [1] to

[10] , further comprising silica.

[12] A cured product of the curable resin composition for stereolithography according to any one of [1] to

[11] .

[13] A three-dimensional object comprising the cured product according to

[12] .

[0009] The curable resin composition for stereolithography of the present invention is capable of producing three-dimensional objects with excellent heat resistance, strength, and flame retardancy. Furthermore, by increasing the concentration of reactive functional groups in the composition, the curable resin composition for stereolithography of the present invention can produce three-dimensional objects at low illuminance, thereby suppressing the decomposition of flame retardants without the use of flame retardant protectors. Furthermore, while the inclusion of non-reactive flame retardants such as metal hydroxides and antimony oxides can cause a decrease in heat resistance, the combination of a bifunctional or higher photopolymerizable monomer with a phosphorus-based flame retardant provides excellent heat resistance while achieving high flame retardancy with a small amount of flame retardant. In this way, three-dimensional objects can be obtained that exhibit both excellent flame retardancy and heat resistance that is useful in practical situations.

[0010] The present invention will be described in detail below. In this specification, "(meth)acrylate" means acrylate and / or methacrylate. Furthermore, "(meth)acryloyl" means acryloyl and / or methacryloyl. Furthermore, "(meth)acrylic" means acrylic and / or methacrylic.

[0011] [Curable Resin Composition for Stereolithography] The curable resin composition for stereolithography of the present invention (hereinafter simply referred to as "the composition of the present invention") contains a polymerizable monomer including a photopolymerizable monomer (A) having two or more photopolymerizable functional groups, a phosphorus-based flame retardant (B), and a photopolymerization initiator. The composition of the present invention may also contain a urethane oligomer (C) as the polymerizable monomer, other polymerizable monomers other than the photopolymerizable monomer (A) and the urethane oligomer (C), additives, etc.

[0012] [Photopolymerizable Monomer (A)] The photopolymerizable monomer (A) having two or more photopolymerizable functional groups is a central component that can increase the concentration of reactive functional groups in the polymerizable monomer, and the photopolymerizable functional group preferably has a (meth)acryloyl group or a vinyl group from the viewpoint of photoreactivity. The photopolymerizable monomer (A) preferably has a glass transition point (Tg) of 100°C or higher when made into a homopolymer from the viewpoint of the heat resistance of the three-dimensionally shaped object. The Tg is preferably 110°C or higher, more preferably 120°C or higher. The photopolymerizable monomer (A) can be used alone or in combination of two or more types.

[0013] Examples of the monomer having two photopolymerizable functional groups include tricyclodecane dimethanol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, hexanediol di(meth)acrylate, EO-modified di(meth)acrylate of bisphenol A, hexanediol EO-modified di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, neopentyl glycol PO-modified di(meth)acrylate, tripropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, (meth)acrylate, polyethylene glycol di(meth)acrylate, glycerin di(meth)acrylate, 2-[2-(vinyloxy)ethoxy]ethyl (meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, EO-modified 1,6-hexanediol di(meth)acrylate Acrylate, propylene oxide-modified neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, PO-modified di(meth)acrylate of bisphenol A, EO-modified di(meth)acrylate of bisphenol F, tricyclodecane dimethanol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, PO-modified tri(meth)acrylate of glycerin, 2-hydroxy-3-acryloyloxypropyl (meth)acrylate, EO-modified di(meth)acrylate of bisphenoxyethanol fluorene, polytetramethylene glycol di(meth)acrylate, phenoxyethylene glycol (meth)acrylate, stearyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, trifluoroethyl (meth)acrylate 3-methyl-1,5 pentanediol di(meth)acrylate, 2,Examples of suitable acrylates include 3-[(meth)acryloyloxymethyl]norbornane, 2,5-[(meth)acryloyloxymethyl]norbornane, 2,6-[(meth)acryloyloxymethyl]norbornane, 1,3-adamantyl di(meth)acrylate, 1,3-bis[(meth)acryloyloxymethyl]adamantane, tris(hydroxyethyl)isocyanuric acid di(meth)acrylate, and 3,9-bis[1,1-dimethyl-2-(meth)acryloyloxyethyl]-2,4,8,10-tetraoxospiro[5.5]undecane. Among these, tricyclodecane dimethanol di(meth)acrylate and ethoxylated bisphenol A di(meth)acrylate are preferred.

[0014] Examples of monomers having three photopolymerizable functional groups include trimethylolpropane tri(meth)acrylate, trimethylolpropane EO-modified tri(meth)acrylate, trimethylolpropane PO-modified tri(meth)acrylate, glycerol propoxy tri(meth)acrylate, pentaerythritol tri(meth)acrylate, EO-modified glycerol acrylate, PO-modified glycerol triacrylate, pentaerythritol triacrylate, EO-modified phosphate triacrylate, trimethylolpropane triacrylate, caprolactone-modified trimethylolpropane triacrylate, HPA-modified trimethylolpropane triacrylate, (EO)- or (PO)-modified trimethylolpropane triacrylate, and alkyl-modified dipentaerythritol triacrylate.

[0015] Examples of monomers having four or more photopolymerizable functional groups include pentaerythritol tetra(meth)acrylate, pentaerythritol EO-modified tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol ethoxy tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hydroxypenta(meth)acrylate, alkyl-modified dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0016] The photopolymerizable monomer (A) preferably has an isocyanuric acid skeleton, since the flame retardancy is improved by the synergistic effect of the nitrogen atom derived from the isocyanuric acid skeleton and the phosphorus atom derived from the phosphorus-based flame retardant (B). Examples of the monomer having an isocyanuric acid skeleton include tris(2-acryloyloxyethyl) isocyanurate and triallyl isocyanurate.

[0017] The content of the photopolymerizable monomer (A) is, for example, 30% by weight or more, preferably 50% by weight or more, and more preferably 70% by weight or more, based on the total amount of polymerizable monomers contained in the composition.

[0018] [Phosphorus-based flame retardant (B)] The phosphorus-based flame retardant (B) is preferably liquid at 23° C. (room temperature) in terms of compatibility with polymerizable monomers such as the photopolymerizable monomer (A). The phosphorus-based flame retardant (B) can be used alone or in combination of two or more.

[0019] Examples of the phosphorus-based flame retardant (B) include ammonium polyphosphate, metal phosphinate, phosphazene, bisphenol A, phenyl, and aromatic condensed phosphate flame retardants, and among these, aromatic phosphate ester flame retardants are particularly preferred because of their improved compatibility. Examples of aromatic phosphate ester flame retardant compounds include cresyl diphenyl phosphate, tricresyl phosphate, triphenyl phosphate, trixylenyl phosphate, 2-ethylhexyl diphenyl phosphate, 2-naphthyl diphenyl phosphate, and cresyl di-2,6-xylenyl phosphate.

[0020] Commercially available phosphorus-based flame retardants include, for example, ammonium polyphosphate-based EXOLIT (registered trademark) AP422, AP423, and AP462 (manufactured by Clariant Chemicals), metal phosphinate-based EXOLIT (registered trademark) OP1230, OP1240, OP1312, and OP1400 (manufactured by Clariant Chemicals), phosphazene-based LAVITOL (registered trademark) FP-110 and FP-100 (manufactured by Mitsui Fine Chemicals, Inc.), bisphenol A-based ADK STAB FP-600 (manufactured by ADEKA), biphenyl-based ADK STAB FP900L (manufactured by ADEKA), and phenyl-based aromatic condensed phosphate ester-based CR-733S and CR-741 (manufactured by Daihachi Chemical Industry Co., Ltd.).

[0021] The content of the phosphorus-based flame retardant (B) is preferably 15 to 45 parts by weight per 100 parts by weight of the polymerizable monomer from the viewpoint of achieving both flame retardancy and heat resistance. When the content of the phosphorus-based flame retardant (B) is within this range, optimal flame retardancy and heat resistance can be imparted to the three-dimensional object. The polymerizable monomer includes the photopolymerizable monomer (A), the urethane oligomer (C), and other polymerizable monomers other than these.

[0022] [Photopolymerization Initiator] Examples of the photopolymerization initiator include 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, thioxanthone and thioxanthone derivatives, 2,2'-dimethoxy-1,2-diphenylethan-1-one, diphenyl(2,4,6-trimethoxybenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate, and polymeric TPO-L.

[0023] Other commercially available photopolymerization initiators include, for example, "Omnirad-1173", "Omnirad-184", "Omnirad-127", "Omnirad-369", "Omnirad-379", "Omnirad-907", "Omnirad-4265", "Omnirad-1000", "Omnirad-651", "Omnirad-TPO", "Omnirad-819", "Omnirad-2022", "Omnirad-2100", "Omnirad-2959", "Omnirad-754", "Omnirad-784", "Omnirad-500", "Omnirad-819", and "Omnirad Examples of suitable antiperspirants include "TPO-L," "Omnipol TP" (manufactured by IGM), "Kayacure-DETX," "Kayacure-MBP," "Kayacure-DMBI," "Kayacure-EPA," and "Kayacure-OA" (manufactured by Nippon Kayaku Co., Ltd.), "Baicure-10," "Baicure-55" (manufactured by Stauffer Chemical Co., Ltd.), "Trigonal P1" (manufactured by Akzo), "Sandray 1000" (manufactured by Sandoz), "Deep" (manufactured by Upjohn), "Quantacure-PDO," "Quantacure-ITX," and "Quantacure-EPD" (manufactured by Ward-Blenkinsop), and "Runtecure-1104" (manufactured by Runtec).

[0024] The content of the photopolymerization initiator is preferably in the range of 0.1 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer.

[0025] [Urethane Oligomer (C)] The composition of the present invention may further contain a urethane oligomer (C) as an optional polymerizable monomer. By containing the urethane oligomer (C), the bending strength of the cured product can be improved. The urethane oligomer (C) is a compound having at least one (meth)acryloyl group and one or more urethane bonds in the molecule, but preferably has two or more (meth)acryloyl groups and two or more urethane bonds. The urethane oligomer (C) can be used alone or in combination of two or more.

[0026] The number average molecular weight (Mn) of the urethane oligomer (C) is, for example, 300 to 10,000, preferably 400 to 9,000, and more preferably 500 to 8,000. When the molecular weight is within this range, a three-dimensionally shaped article having excellent heat resistance and strength can be obtained.

[0027] As the urethane oligomer (C), it is preferable to use a polyfunctional urethane acrylate such as diurethane dimethacrylate, etc. Also, compounds represented by the following chemical formulas (C1) to (C6) are preferred. Commercially available products may also be used from the viewpoint of availability, and examples thereof include those manufactured by Daicel Allnex Co., Ltd. under the trade names "EBECRYL220", "EBECRYL4513", "EBECRYL4738", "EBECRYL4740", "EBECRYL8311", "EBECRYL9260", "EBECRYL8701", "KRM8667", "KRM8296", "EBECRYL4265", "EBECRYL4587", "EBECRYL4666", "EBECRYL8210", "EBECRYL1290", "EBECRYL5129", "EBECRYL8301R", "KRM8200", "KRM8904", and "KRM8451"; and those manufactured by MIWON Co., Ltd. under the trade names "MIRAMER PU340" and "MIRAMER PU3450", "MIRAMER PU5000", "MIRAMER PU610", "MIRAMER PU6510", "MIRAMER PU9500", "MIRAMER PU9800", "MIRAMER SC2100", "MIRAMER SC2565", "MIRAMER PU370", "MIRAMER PU640", etc. can be used. (C1) (C2) (C3) (C4) (C5) (C6)

[0028] The urethane oligomer (C) preferably has an isocyanuric acid skeleton. That is, it is preferable that either the photopolymerizable monomer (A) or the urethane oligomer (C), or both, have an isocyanuric acid skeleton. The composition of the present invention, which combines a tri- or higher functional urethane oligomer (C), a compound having an isocyanuric acid skeleton, and a phosphorus-based flame retardant (B), enables the production of a three-dimensional object with particularly excellent heat resistance and flame retardancy. In particular, the tri- or higher functional urethane oligomer (C) exhibits particularly excellent heat resistance due to improved crosslink density and rigidification of the resin structure. Furthermore, by combining a compound having an isocyanuric acid skeleton, the flame retardancy is significantly improved due to the synergistic effect of the nitrogen atom derived from the isocyanuric acid skeleton and the phosphorus atom derived from the phosphorus-based flame retardant (B). When the composition of the present invention contains a compound having an isocyanuric acid skeleton, the content thereof (total content when multiple compounds are included) is preferably 10 to 40 parts by weight, more preferably 15 to 30 parts by weight, per 100 parts by weight of the polymerizable monomer.

[0029] Examples of compounds having an isocyanuric acid skeleton include compounds represented by the following chemical formulas (C7) and (C8). (C7) (C8)

[0030] The urethane oligomer (C) can be obtained, for example, by reacting a polyisocyanate (a1) with a compound (a2) having a hydroxyl group and a (meth)acryloyl group. A compound (a3) ​​having a hydroxyl group other than the compound (a2) may also be used as a reaction raw material.

[0031] The polyisocyanate (a1) is not particularly limited as long as it can form the urethane resin (A) used in the present invention having a specific content of (meth)acryloyl groups, and can be appropriately selected depending on the purpose. Examples of the diisocyanate include aliphatic diisocyanate compounds such as butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate; alicyclic diisocyanate compounds such as norbornane diisocyanate, isophorone diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate; aromatic diisocyanate compounds such as tolylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diisocyanato-3,3'-dimethylbiphenyl, and o-tolidine diisocyanate; and isocyanurate-modified, biuret-modified, and allophanate-modified diisocyanates thereof.

[0032] Furthermore, if the polyisocyanate (a1) is particularly isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, or an isocyanurate-modified product of hexamethylene diisocyanate, it is more preferable in terms of forming a cured product that has both high heat resistance and flame retardancy.

[0033] The compound (a2) having a hydroxyl group and a (meth)acryloyl group is not particularly limited as long as it can form a urethane resin (A) having at least one (meth)acryloyl group in the molecule, and can be appropriately selected depending on the purpose. Examples thereof include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, trimethylolpropane (meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol (meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol (meth)acrylate, dipentaerythritol di(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane (meth)acrylate, ditrimethylolpropane di(meth)acrylate, and ditrimethylolpropane tri(meth)acrylate. Also usable are (poly)oxyalkylene modified compounds in which a (poly)oxyalkylene chain such as a (poly)oxyethylene chain, a (poly)oxypropylene chain or a (poly)oxytetramethylene chain has been introduced into the molecular structure of the above-mentioned various compounds having a hydroxyl group and a (meth)acryloyl group, and lactone modified compounds in which a (poly)lactone structure has been introduced into the molecular structure of the above-mentioned various compounds having a hydroxyl group and a (meth)acryloyl group.

[0034] Furthermore, when the compound (a2) having a hydroxyl group and a (meth)acryloyl group is, in particular, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate (for example, various products under the trade name "ARONIX" (registered trademark) manufactured by Toagosei Co., Ltd. (M-306, M-305, M-303, M-452, M-450, etc.)), or dipentaerythritol penta(meth)acrylate (for example, various products under the trade name "ARONIX" (registered trademark) manufactured by Toagosei Co., Ltd. (M-400, M-403, M-404, M-405, M-406, MT-3545, etc.)), it is more preferable to form a cured product that combines high heat resistance and flame retardancy.

[0035] The compound (a3) ​​having a hydroxyl group is not particularly limited as long as it is a compound having a hydroxyl group but not a (meth)acryloyl group in the molecule, and can be appropriately selected depending on the purpose. For example, polyhydric alcohols having a linear alkyl structure such as ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, etc.; polyhydric alcohols having a branched alkyl structure such as 3-methyl-1,5-pentanediol, neopentyl glycol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, etc.; polycarbonate polyols synthesized by transesterification of these polyhydric alcohols with carbonate esters; polyester polyols synthesized by dehydration condensation of the above polyhydric alcohols with dibasic acids; polytetramethylene ether glycol, polyethylene glycol, polypropylene glycol, copolymers of polyethylene glycol and polypropylene glycol, etc. can be used.

[0036] The method for producing the urethane oligomer (C) is not particularly limited, and any method may be used. For example, the urethane oligomer (C) may be produced by reacting the polyisocyanate (a1) and the compound (a2) having a hydroxyl group and a (meth)acryloyl group in a single reaction, or by dividing the reactants and reacting them sequentially. The compound (a3) ​​having a hydroxyl group may or may not be used as a reactant.

[0037] In producing the urethane oligomer (C), for example, dibutyltin laurate, dibutyltin acetate, etc. can be used as a catalyst, and the production can be carried out under the conditions for a commonly performed urethanization reaction. If necessary, a solvent such as ethyl acetate, butyl acetate, methyl isobutyl ketone, toluene, xylene, etc., or a radical polymerizable monomer that does not contain a site reactive with isocyanate and does not contain a hydroxyl group or an amino group, can also be used as a solvent.

[0038] The content of the urethane oligomer (C) is, for example, 10 to 55% by weight, preferably 15 to 50% by weight, based on the total amount of the polymerizable monomers including the photopolymerizable monomer (A) and the urethane oligomer (C). When the content of the urethane oligomer (C) is within the above range, the bending strength of the cured product can be further improved.

[0039] [Other Polymerizable Monomers] The composition of the present invention may contain, as a polymerizable monomer, a polymerizable monomer other than the photopolymerizable monomer (A) and the urethane oligomer (C). Examples of the other polymerizable monomers include monofunctional (meth)acrylic compounds.

[0040] Examples of monofunctional (meth)acrylic compounds include phenoxyethyl (meth)acrylate, phenoxybenzyl (meth)acrylate, cyclohexyl (meth)acrylate, trimethylcyclohexyl (meth)acrylate, cyclohexylmethyl (meth)acrylate, cyclohexylethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dipropylene glycol mono(meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, isononyl (meth)acrylate, benzyl (meth)acrylate, ) acrylate, phenylbenzyl (meth)acrylate, lauryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl ( (meth)acrylate, 2-ethylmethoxy (meth)acrylate, 2-ethylethoxy (meth)acrylate, 2-ethylbutoxy (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, butoxydiethylene glycol (meth)acrylate, butoxytriethylene glycol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, 2- Hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl hexahydrophthalate, glycidyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate,Dicyclopentanyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, pentamethylpiperidinyl (meth)acrylate, tetramethylpiperidinyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, 3,4-epoxycyclohexylmethyl methacrylate, cyclic trimethylolpropane formal (meth)acrylate, 1-adamantyl (meth)acrylate, 2-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, glycerin Examples of the monofunctional (meth)acrylate compound include monofunctional (meth)acrylate compounds such as methyl carbonate (meth)acrylate, tert-butylcyclohexyl (meth)acrylate, 2-(1,2-cyclohexanedicarboximide)ethyl (meth)acrylate, o-phenylphenoxyethyl (meth)acrylate, and phenoxyethyl (meth)acrylate; and monofunctional (meth)acrylamide compounds such as (meth)acryloylmorpholine, isopropyl(meth)acrylamide, dimethyl(meth)acrylamide, hydroxyethyl(meth)acrylamide, and diethyl(meth)acrylamide.

[0041] [Additives] The composition of the present invention may contain various additives, such as a photosensitizer, an ultraviolet absorber, an antioxidant, a polymerization inhibitor, a silicon-based additive, a fluorine-based additive, a silane coupling agent, organic beads, inorganic fine particles, an organic filler, an inorganic filler, a rheology control agent, a defoaming agent, and a colorant, as needed.

[0042] Examples of the photosensitizer include amine compounds such as aliphatic amines and aromatic amines, urea compounds such as o-tolylthiourea, condensed polycyclic compounds such as anthraquinone derivatives, and sulfur compounds such as sodium diethyldithiophosphate and s-benzylisothiuronium-p-toluenesulfonate.

[0043] Examples of ultraviolet absorbers include triazine derivatives such as 2-[4-{(2-hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-{(2-hydroxy-3-tridecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2'-xanthenecarboxy-5'-methylphenyl)benzotriazole, 2-(2'-o-nitrobenzyloxy-5'-methylphenyl)benzotriazole, 2-xanthenecarboxy-4-dodecyloxybenzophenone, and 2-o-nitrobenzyloxy-4-dodecyloxybenzophenone. These ultraviolet absorbers can be used alone or in combination of two or more.

[0044] Examples of antioxidants include hindered phenol antioxidants, hindered amine antioxidants, organic sulfur antioxidants, and phosphate ester antioxidants. These antioxidants can be used alone or in combination of two or more.

[0045] Examples of the polymerization inhibitor include hydroquinone, methoquinone, di-t-butylhydroquinone, p-methoxyphenol, butylhydroxytoluene, and nitrosamine salts.

[0046] Examples of silicon-based additives include polyorganosiloxanes having alkyl or phenyl groups, such as dimethylpolysiloxane, methylphenylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, polyether-modified dimethylpolysiloxane copolymer, polyester-modified dimethylpolysiloxane copolymer, fluorine-modified dimethylpolysiloxane copolymer, and amino-modified dimethylpolysiloxane copolymer, polydimethylsiloxanes having polyether-modified acrylic groups, and polydimethylsiloxanes having polyester-modified acrylic groups. These silicon-based additives can be used alone or in combination of two or more.

[0047] Examples of fluorine-based additives include the "Megaface" series manufactured by DIC Corporation. These fluorine-based additives can be used alone or in combination of two or more.

[0048] Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, Silane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimeth Xysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, special aminosilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatopropyltriethoxysilane, allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane vinyl-based silane coupling agents such as vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-methoxyethoxy)silane; epoxy-based silane coupling agents such as diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; styrene-based silane coupling agents such as p-styryltrimethoxysilane;(Meth)acryloxy-based silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane; N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-triethoxysilyl-N-(1,3-dimethyl)- Examples of suitable silane coupling agents include amino-based silane coupling agents such as N-butylidene)propylamine and N-phenyl-3-aminopropyltrimethoxysilane; ureido-based silane coupling agents such as 3-ureidopropyltriethoxysilane; chloropropyl-based silane coupling agents such as 3-chloropropyltrimethoxysilane; mercapto-based silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane; sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide; and isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane. These silane coupling agents can be used alone or in combination of two or more.

[0049] Examples of organic beads include polymethyl methacrylate beads, polycarbonate beads, polystyrene beads, polyacrylic styrene beads, silicone beads, glass beads, acrylic beads, benzoguanamine resin beads, melamine resin beads, polyolefin resin beads, polyester resin beads, polyamide resin beads, polyimide resin beads, polyethylene fluoride resin beads, and polyethylene resin beads. These organic beads can be used alone or in combination of two or more types. Furthermore, the average particle size of these organic beads is preferably in the range of 1 to 10 μm.

[0050] Examples of inorganic fine particles include silica, alumina, zirconia, titania, barium titanate, and antimony trioxide. These inorganic fine particles can be used alone or in combination of two or more. The average particle size of these inorganic fine particles is preferably in the range of 0.05 to 3 μm, and more preferably in the range of 0.1 to 1 μm. The silica is not limited, and known silica fine particles such as powdered silica and colloidal silica can be used. Commercially available powdered silica fine particles include, for example, the "Aerosil (registered trademark)" series (50, 200, etc.) manufactured by Nippon Aerosil Co., Ltd., the "Sildex" series (H31, H32, H51, H52, H121, H122, etc.) manufactured by AGC, the "E220A" or "E220" manufactured by Tosoh Silica Corporation, the "SYLYSIA (registered trademark) 470" manufactured by Fuji Silysia Chemical Ltd., and the "Sildex" series (H31, H32, H51, H52, H121, H122, etc.) manufactured by Nippon Sheet Glass Co., Ltd. Examples of such products include those manufactured by Admatechs Co., Ltd. under the trade name "SG Flake," those manufactured by Adma Fine series (SC1500-SMJ, SC2500-SMJ, SC4500-SMJ, etc.) and those manufactured by Admanano series (YC100, etc.), those manufactured by Tokuyama Corporation under the trade names "Reoloseal," "Silfil," and "Sunseal," and those manufactured by Nippon Shokubai Co., Ltd. under the product name "Seahoster" series (S10, S30, S50, S100, etc.). Furthermore, commercially available colloidal silica can be used by removing the solvent from products such as "Methanol Silica Sol," "IPA-ST," "MEK-ST," "PGM-ST," "NBA-ST," "XBA-ST," "DMAC-ST," "ST-UP," "ST-OUP," "ST-20," "ST-40," "ST-C," "ST-N," "ST-O," "ST-50," "ST-OL," "MIBK-SD," "MIBK-SD-L," "MIBK-AC-2140Z," and "MEK-AC-2140Z," manufactured by Nissan Chemical Industries, Ltd.

[0051] When inorganic fine particles are contained, a dispersing aid can be used. Examples of dispersing aids include phosphate ester compounds such as isopropyl acid phosphate, triisodecyl phosphite, and ethylene oxide-modified phosphate dimethacrylate. These dispersing aids can be used alone or in combination of two or more. In addition, examples of commercially available dispersing aids include "Kayamar PM-21" and "Kayamar PM-2" manufactured by Nippon Kayaku Co., Ltd., and "Light Ester P-2M" manufactured by Kyoeisha Chemical Co., Ltd.

[0052] Examples of organic fillers include plant-derived solvent-insoluble substances such as cellulose, lignin, and cellulose nanofibers. Examples of inorganic fillers include glass (particles), silica (particles), alumina silicate, talc, mica, aluminum hydroxide, alumina, calcium carbonate, and carbon nanotubes.

[0053] Examples of rheology control agents include amide waxes such as "Disparlon 6900" manufactured by Kusumoto Chemicals Co., Ltd.; urea-based rheology control agents such as "BYK410" manufactured by BYK-Chemie; polyethylene waxes such as "Disparlon 4200" manufactured by Kusumoto Chemicals Co., Ltd.; and cellulose acetate butyrates such as "CAB-381-2" and "CAB 32101" manufactured by Eastman Chemical Products Co. Examples of defoaming agents include oligomers containing fluorine or silicon atoms, or oligomers of higher fatty acids, acrylic polymers, etc.

[0054] Examples of colorants include pigments and dyes. Known and commonly used inorganic and organic pigments can be used as pigments. Examples of inorganic pigments include titanium oxide, antimony red, red iron oxide, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine blue, carbon black, and graphite. Examples of organic pigments include quinacridone pigments, quinacridonequinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, and azo pigments. These pigments can be used alone or in combination of two or more.

[0055] Examples of dyes include azo dyes such as monoazo and disazo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinoimine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, naphthalimide dyes, perinone dyes, phthalocyanine dyes, triarylmethane dyes, etc. These dyes can be used alone or in combination of two or more.

[0056] [Cured Product] The cured product of the present invention is obtained by photocuring the composition of the present invention by irradiating it with active energy rays or the like. Examples of active energy rays include ionizing radiation such as ultraviolet rays, electron beams, α rays, β rays, and γ rays. When ultraviolet rays are used as the active energy rays, irradiation may be carried out in an inert gas atmosphere such as nitrogen gas, or in an air atmosphere, in order to efficiently carry out the curing reaction by ultraviolet rays.

[0057] As a source of ultraviolet light, ultraviolet lamps are generally used from the viewpoints of practicality and economy, and specific examples include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, sunlight, and LEDs.

[0058] The cumulative amount of active energy rays is not particularly limited, but is preferably 50 to 5,000 mJ / cm２ is preferably 300 to 1,000 mJ / cm ２ It is more preferable that the integrated light amount is within the above range, since it is possible to prevent or suppress the occurrence of uncured portions.

[0059] [Three-dimensional object] The three-dimensional object of the present invention is made of the cured product and can be produced by a known optical three-dimensional modeling method using a 3D printer or the like. Examples of optical three-dimensional modeling methods include stereolithography (SLA), digital light processing (DLP), and inkjet. Among these, it is preferable to use a digital light processing (DLP) 3D printer because it enables high-speed modeling using surfaces and easily exhibits the effects of the composition of the present invention.

[0060] The stereolithography (SLA) method is a method in which a tank of liquid curable resin composition is irradiated with active energy rays such as laser beams at points, and the composition is cured layer by layer while the modeling stage is moved, resulting in a three-dimensional model.The digital light processing (DLP) method is a method in which a tank of liquid curable resin composition is irradiated with active energy rays such as LEDs at surfaces, and the composition is cured layer by layer while the modeling stage is moved, resulting in a three-dimensional model.The inkjet stereolithography method is a method in which minute droplets of a stereolithography curable resin composition are ejected from a nozzle to draw a predetermined shape pattern, and then ultraviolet light is irradiated to form a cured thin film.

[0061] The DLP three-dimensional modeling method is not particularly limited as long as it is a method using a DLP optical modeling system. However, as for the modeling conditions, in order to improve the modeling accuracy of the three-dimensional model, it is preferable that the layer pitch of the optical modeling is in the range of 0.01 to 0.2 mm, the irradiation wavelength is in the range of 350 to 410 nm, and the light intensity is in the range of 0.5 to 50 mW / cm. ２ The integrated light amount per layer is in the range of 1 to 100 mJ / cm ２ In particular, in order to improve the molding accuracy of the three-dimensional object, the layer pitch of the photolithography is in the range of 0.02 to 0.1 mm, the irradiation wavelength is in the range of 365 to 410 nm, and the light intensity is in the range of 5 to 15 mW / cm. ２The integrated light amount per layer is in the range of 5 to 15 mJ / cm ２ The three-dimensional object obtained by stereolithography may be irradiated with active energy rays from multiple directions to form a final three-dimensional object. This irradiation step is called post-curing.

[0062] The three-dimensional object of the present invention has both heat resistance and flame retardancy, and therefore can be suitably used in applications requiring heat resistance and flame retardancy, such as electric and electronic parts, automobile parts, furniture, and home appliance parts.

[0063] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0064] The materials used in the following examples and shown in the tables are as follows: MIRAMER M262: Tricyclodecane dimethanol diacrylate (manufactured by MIWON Corporation) MIRAMER M240: Bisphenol A EO-modified diacrylate (manufactured by MIWON Corporation) ARONIX M-315: Tris(2-acryloyloxyethyl) isocyanurate (manufactured by Toagosei Co., Ltd.) ARONIX M-305: Reaction product of pentaerythritol and acrylic acid, with pentaerythritol triacrylate as the main component (manufactured by Toagosei Co., Ltd.) ARONIX MT-3545: Reaction product of dipentaerythritol and acrylic acid, with dipentaerythritol tetraacrylate as the main component (manufactured by Toagosei Co., Ltd.) WANNATE HT-600: Hexamethylene diisocyanate polymer (isocyanurate-modified) (manufactured by WANHUA Corporation) TAICROS (registered trademark): triallyl isocyanurate (manufactured by Evonik Degussa) VEEA (registered trademark): 2-(2-vinyloxyethoxy)ethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.) NK Ester DCP: tricyclodecane dimethanol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) VISIOMER HEMATMDI (registered trademark): diurethane dimethacrylate (manufactured by Evonik) Urethane (C-1): urethane oligomer having as the main component the above formula (C1) (Synthesis Example 1) Urethane (C-2): urethane oligomer having as the main component the above formula (C2) (Synthesis Example 2) Urethane (C-3): urethane oligomer having as the main component the above formula (C3) (Synthesis Example 3) Urethane (C-4): urethane oligomer having as the main component the above formula (C4) (Synthesis Example 4) Urethane (C-5): Urethane oligomer having the above formula (C5) as the main component (Synthesis Example 5) Urethane (C-6): Urethane oligomer having the above formula (C6) as the main component (Synthesis Example 6) Urethane (C-7): Urethane oligomer having the above formula (C7) as the main component (Synthesis Example 7) Urethane (C-8): Urethane oligomer having the above formula (C8) as the main component (Synthesis Example 8) ACMO: Acryloylmorpholine (KJ Chemicals), Tg 145°C Firecut P-801: Ethylenebispentabromobenzene (Suzuhiro Chemical Industry Co., Ltd.) Kisuma 5E: Magnesium hydroxide (Kyowa Chemical Industry Co., Ltd.) EXOLIT AP422: Ammonium polyphosphate flame retardant (manufactured by Clariant Chemicals) EXOLIT AP 1230: Metal phosphinate flame retardant (manufactured by Clariant Chemicals) Ravitor FP-100: Phosphazene flame retardant (manufactured by Mitsui Fine Chemicals) PX-200: Aromatic condensed phosphate ester flame retardant (manufactured by Daihachi Chemical Industry Co., Ltd.) Adeka STAB FP-600: Condensed phosphate ester flame retardant (manufactured by ADEKA Corporation) Adeka STAB FP-900L: Condensed phosphate ester flame retardant (manufactured by ADEKA Corporation) Fireguard FCX-210: Spirocyclic diphosphonate compound (manufactured by Teijin Limited) CR-733S: Aromatic condensed phosphate ester flame retardant (manufactured by Daihachi Chemical Industry Co., Ltd.) ADMAFINE SC2500-SMJ: spherical silica (manufactured by Admatechs Co., Ltd.) Omnirad 819: bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (manufactured by IGM Resins Co., Ltd.)

[0065] Synthesis Example 1: Synthesis of Urethane Oligomer (C-1) A 1-liter flask equipped with a stirrer, a gas inlet tube, a condenser, and a thermometer was charged with Aronix M-305 (409 parts by weight), tertiary butylhydroxytoluene (1.0 part by weight), methoxyhydroquinone (0.1 part by weight), and dibutyltin diacetate (0.1 part by weight), and the temperature was raised to 70°C. 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI; 90 parts by weight) was added in portions over 1 hour. After the addition, a 2250 cm3 (indicating an isocyanate group) was obtained. －１ The reaction was continued at 70°C until the infrared absorption spectrum of the above disappeared, yielding a urethane oligomer (C-1) mainly composed of the above formula (C1). The number average molecular weight (Mn) of the urethane oligomer (C-1) was 800.

[0066] (Synthesis Example 2: Synthesis of Urethane Oligomer (C-2)) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with Aronix M-305 (395 parts by weight), tertiary butylhydroxytoluene (1.0 part by weight), methoxyhydroquinone (0.1 part by weight), and dibutyltin diacetate (0.1 part by weight). The temperature was raised to 70°C, and dicyclohexylmethane 4,4'-diisocyanate (H12MDI; 104 parts by weight) was added in portions over 1 hour. After charging, the reaction was carried out at 70°C until the infrared absorption spectrum at 2250 cm-1, which indicates an isocyanate group, disappeared, yielding a urethane oligomer (C-2) composed primarily of the above formula (C2). The number average molecular weight (Mn) of the urethane oligomer (C-2) was 900.

[0067] Synthesis Example 3: Synthesis of Urethane Oligomer (C-3) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with Aronix M-305 (418 parts by weight), tertiary butylhydroxytoluene (1.0 parts by weight), methoxyhydroquinone (0.1 parts by weight), and dibutyltin diacetate (0.1 parts by weight). The temperature was raised to 70°C, and 1,3-bis(isocyanatomethyl)cyclohexane (H6XDI; 81 parts by weight) was added in portions over 1 hour. After charging, the reaction was carried out at 70°C until the infrared absorption spectrum at 2250 cm-1, which indicates an isocyanate group, disappeared, yielding a urethane oligomer (C-3) composed primarily of the above formula (C3). The number average molecular weight (Mn) of the urethane oligomer (C-3) was 800.

[0068] (Synthesis Example 4: Synthesis of Urethane Oligomer (C-4)) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with Aronix M-305 (413 parts by weight), tertiary butylhydroxytoluene (1.0 parts by weight), methoxyhydroquinone (0.1 parts by weight), and dibutyltin diacetate (0.1 parts by weight), and the temperature was raised to 70 ° C., and norbornane diisocyanate (NBDI; 85 parts by weight) was charged in portions over 1 hour. After charging, the reaction was carried out at 70 ° C. until the infrared absorption spectrum at 2250 cm −1 indicating an isocyanate group disappeared, and a urethane oligomer (C-4) having the above formula (C4) as the main component was obtained. The number average molecular weight (Mn) of the urethane oligomer (C-4) was 800.

[0069] (Synthesis Example 5: Synthesis of Urethane Oligomer (C-5)) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with Aronix M-305 (412 parts by weight), tertiary butylhydroxytoluene (1.0 parts by weight), methoxyhydroquinone (0.1 parts by weight), and dibutyltin diacetate (0.1 parts by weight), and the temperature was raised to 70°C. Naphthalene-1,5-diisocyanate (NaphDI; 87 parts by weight) was added in portions over 1 hour. After charging, the reaction was carried out at 70°C until the infrared absorption spectrum at 2250 cm-1, which indicates an isocyanate group, disappeared, and a urethane oligomer (C-5) composed mainly of the above formula (C5) was obtained. The number average molecular weight (Mn) of the urethane oligomer (C-5) was 800.

[0070] (Synthesis Example 6: Synthesis of Urethane Oligomer (C-6)) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with Aronix MT-3545 (DPET-PA; 386 parts by weight), tertiary butylhydroxytoluene (1.0 parts by weight), methoxyhydroquinone (0.1 parts by weight), and dibutyltin diacetate (0.1 parts by weight), and the temperature was raised to 70°C. Dicyclohexylmethane 4,4'-diisocyanate (H12MDI; 113 parts by weight) was added in portions over 1 hour. After charging, the reaction was carried out at 70°C until the infrared absorption spectrum at 2250 cm-1, which indicates an isocyanate group, disappeared, and a urethane oligomer (C-6) composed mainly of the above formula (C6) was obtained. The number average molecular weight (Mn) of the urethane oligomer (C-6) was 1300.

[0071] (Synthesis Example 7: Synthesis of Urethane Oligomer (C-7)) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with WANNATE HT-600 (303 parts by weight), tertiary butylhydroxytoluene (1.0 parts by weight), methoxyhydroquinone (0.1 parts by weight), and dibutyltin diacetate (0.1 parts by weight), and the temperature was raised to 70 ° C., and 2-hydroxyethyl acrylate (HEA; 196 parts by weight) was added in portions over 1 hour. After charging, the reaction was carried out at 70 ° C. until the infrared absorption spectrum at 2250 cm −1 indicating an isocyanate group disappeared, and a urethane oligomer (C-7) composed mainly of the above formula (C7) was obtained. The number average molecular weight (Mn) of the urethane oligomer (C-7) was 900.

[0072] (Synthesis Example 8: Synthesis of Urethane Oligomer (C-8)) A 1-liter flask equipped with a stirrer, gas inlet tube, condenser, and thermometer was charged with Aronix M-305 (366 parts by weight), tertiary butylhydroxytoluene (1.0 parts by weight), methoxyhydroquinone (0.1 parts by weight), and dibutyltin diacetate (0.1 parts by weight), and the temperature was raised to 70 ° C., and WANNATE HT-600 (133 parts by weight) was added in portions over 1 hour. After charging, the reaction was carried out at 70 ° C. until the infrared absorption spectrum at 2250 cm −1 indicating an isocyanate group disappeared, and a urethane oligomer (C-8) having the above formula (C8) as the main component was obtained. The number average molecular weight (Mn) of the urethane oligomer (C-8) was 1400.

[0073] Example 1 Preparation of Curable Resin Composition (1) To a four-neck flask equipped with a stirrer, a thermometer, and a condenser, 70 parts by weight of MIRAMER M262 manufactured by MIWON, 30 parts by weight of EXOLIT AP 422 manufactured by Clariant Chemicals, and 1.2 parts by weight of Omnirad 819 manufactured by IGM Resins were added, and the mixture was stirred at 60°C or less until uniformly dissolved, thereby obtaining a curable resin composition (1).

[0074] (Examples 2 to 23: Preparation of curable resin compositions (2) to (23)) Curable resin compositions (2) to (23) were obtained in the same manner as in Example 1, except that the photopolymerizable monomer (A), the phosphorus-based flame retardant (B), and the urethane oligomer (C) in Example 1 were changed to the compositions and blending amounts (unit: parts by weight) shown in Tables 1 to 3.

[0075] Comparative Examples 1 to 4: Preparation of Curable Resin Compositions (R1) to (R4) Curable resin compositions (R1) to (R4) were obtained in the same manner as in Example 1, except that the urethane resin and the (meth)acrylic compound in Example 1 were changed to the compositions and blending amounts shown in Table 3.

[0076] Using the curable resin compositions obtained in Examples 1 to 23 and Comparative Examples 1 to 4, stereolithography was carried out using a stereolithography 3D printer ("Vittro P100" manufactured by 3D'LIGHT). The stereolithography was carried out at a power of 2.5 mW / cm per layer. ２The irradiation was performed at an illuminance of 10 ...

[0077] [Flexural strength] The test was performed according to ASTM D790 Plastic Bending Test Method. A bending strength evaluation of 80 MPa or more was rated as ⊚ (very good), 50 MPa or more but less than 80 MPa was ◯ (good), 20 MPa or more but less than 50 MPa was △ (slightly poor), and less than 20 MPa was x (poor).

[0078] [Heat resistance] A deflection temperature under load test (HDT) was performed according to ASTM D 648. A deflection temperature under load (heat distortion temperature) of 90°C or higher was rated as ⊚ (very good), 60°C or higher but less than 90°C was rated as ◯ (good), 45°C or higher but less than 60°C was Δ (slightly poor), and less than 45°C was rated as × (poor).

[0079] [Flame retardancy] A flammability test was conducted based on the UL94 standard. Samples (test pieces: length 125 mm, width 13.0 mm) were prepared using the same method as above with thicknesses (heights) of 3 mm and 2 mm as well as 4 mm. Flame retardancy was evaluated as follows. The following "1" to "5" were considered to be pass: 5: Test piece thicknesses of 2 mm, 3 mm, and 4 mm all at V-0 level 4: Test piece thicknesses of 3 mm and 4 mm at V-0 level 3: Test piece thickness of 4 mm at V-0 level 2: Test piece thickness of 4 mm at V-1 level 1: Test piece thickness of 4 mm at V-2 level Fail: Other than the above

[0080]

[0081]

[0082]

[0083] It is clear that the compositions of Examples 1 to 8, which contain a photopolymerizable monomer (A) and a phosphorus-based flame retardant (B), are able to maintain high flame retardancy while also maintaining flexural strength and heat resistance. It is also clear that the compositions of Examples 9 to 23, which further contain a urethane oligomer (C), are able to maintain high flame retardancy while also maintaining flexural strength and heat resistance.

Claims

1. A curable resin composition for stereolithography, comprising a polymerizable monomer including a photopolymerizable monomer (A) having two or more photopolymerizable functional groups, a phosphorus-based flame retardant (B), and a photopolymerization initiator.

2. The curable resin composition for stereolithography according to claim 1, wherein the homopolymer of the photopolymerizable monomer (A) has a glass transition temperature of 100° C. or higher.

3. The curable resin composition for stereolithography according to claim 1, wherein the phosphorus-based flame retardant (B) is an aromatic phosphate ester-based flame retardant.

4. The curable resin composition for stereolithography according to claim 1, wherein the phosphorus-based flame retardant (B) is liquid at 23°C.

5. The curable resin composition for stereolithography according to claim 1, which contains 15 to 45 parts by weight of the phosphorus-based flame retardant (B) per 100 parts by weight of the polymerizable monomer.

6. The curable resin composition for stereolithography according to claim 1, further comprising a urethane oligomer (C) having two or more urethane bonds in one molecule as the polymerizable monomer.

7. The curable resin composition for stereolithography according to claim 6, wherein the urethane oligomer (C) has three or more (meth)acryloyl groups in one molecule.

8. The curable resin composition for stereolithography according to claim 6, wherein either the photopolymerizable monomer (A) or the urethane oligomer (C), or both, have an isocyanuric acid skeleton.

9. The curable resin composition for stereolithography according to claim 1, which is used in a digital light processing type 3D printer.

10. The curable resin composition for stereolithography according to claim 6, wherein the content of the urethane oligomer (C) is 10 to 55% by weight based on the total amount of the polymerizable monomer and the urethane oligomer (C).

11. The curable resin composition for stereolithography according to claim 1, further comprising silica.

12. A cured product of the curable resin composition for stereolithography according to any one of claims 1 to 11.

13. A three-dimensional object made from the cured product according to claim 12.

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