Photocurable resin composition, its cured product, and method for producing the stereochemical product.

Abstract

To provide a photocurable resin composition which is suitably usable for three-dimensional molding, and enables production of a cured product that has high elastic modulus and is excellent in impact resistance.SOLUTION: A photocurable resin composition contains polyfunctional urethane (meth)acrylate (a1) that has at least two (meth)acryloyl groups and two urethane groups in the molecule, and includes a structure represented by general formula (1) or (2) as a polyfunctional radical-polymerizable compound (A), in which a content of the polyfunctional urethane (meth)acrylate (a1) to 100 pts.mass of the total amount of the polyfunctional radical-polymerizable compound (A) and a monofunctional radical-polymerizable compound (B) is 10 pts.mass or more and 60 pts.mass or less, and a content of rubber particles (C) to 100 pts.mass of the total amount of the polyfunctional radical-polymerizable compound (A) and the monofunctional radical-polymerizable compound (B) is 2 pts.mass or more and less than 18 pts.mass.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to a photocurable resin composition, its cured product, and a method for producing a stereochemical object. [Background technology]

[0002] Optical stereolithography (hereinafter referred to as "stereolithography") is a known method of creating objects by repeatedly selectively irradiating a photocurable resin composition with light based on the three-dimensional shape of a 3D model to form a cured resin layer, thereby creating an object in which the cured resin layer is integrally laminated. Stereolithography can easily create even complex three-dimensional objects if three-dimensional shape data of a 3D model is available, and its application to the creation of prototypes for shape confirmation, working models and molds for functionality verification is progressing. Furthermore, in recent years, it has begun to spread to the creation of actual products.

[0003] Against this backdrop, there is a need for a photocurable resin composition that can create articles with high impact resistance comparable to general-purpose engineering plastics such as ABS, and high heat resistance that prevents deformation even at relatively high temperatures. Furthermore, the articles are also required to have high hardness, i.e., high elastic modulus, which allows them to withstand high stress against deformation.

[0004] Patent Document 1 discloses a photocurable resin composition comprising a cationic polymerizable compound (A) having two or more bisphenol structures and one or more hydroxyl groups, a cationic polymerizable compound other than component (A), a radical polymerizable compound, and multilayer polymer particles. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-266551 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the cured product of the photocurable resin composition described in Patent Document 1 is not sufficient in terms of achieving both mechanical strength and elastic modulus suitable for the molding of actual products. Although its elastic modulus is excellent at 2 GPa or higher, its impact resistance is significantly lower than that of ABS. [Means for solving the problem]

[0007] The present invention aims to provide a photocurable resin composition that can produce a cured product having a high modulus of elasticity and excellent impact resistance.

[0008] The photocurable resin composition according to the present invention is a photocurable resin composition comprising a polyfunctional radical polymerizable compound (A), a monofunctional radical polymerizable compound (B), rubber particles (C) made of a diene compound, and a radical polymerization initiator (D), wherein the polyfunctional radical polymerizable compound (A) includes a polyfunctional urethane (meth)acrylate (a1) having at least two (meth)acryloyl groups and two urethane groups in its molecule and having a structure represented by general formula (1) or (2), the content of the polyfunctional urethane (meth)acrylate (a1) per 100 parts by mass of the total amount of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B) is 10 parts by mass or more and 60 parts by mass or less, and the content of the rubber particles (C) per 100 parts by mass of the total amount of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B) is 2 parts by mass or more and less than 18 parts by mass.

[0009] [ka]

[0010] [ka]

[0011] [In general formulas (1) and (2), R1 and R2 are each independent hydrocarbon groups containing alkylene groups with 1 to 18 carbon atoms, and n is between 2 and 50.] Effects of the Invention

[0012] According to the present disclosure, it is possible to form a cured product having a high elastic modulus and excellent impact resistance and heat resistance, and to provide a photocurable resin composition suitable for three-dimensional modeling. Brief Description of the Drawings

[0013] [Figure 1] It is a schematic diagram showing a configuration example of a stereolithography apparatus. Mode for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described. The embodiments described below are merely examples, and the present invention is not limited to these embodiments unless specifically stated otherwise.

[0015] <Photocurable Resin Composition> The photocurable resin composition according to the present invention is produced by placing a polyfunctional radically polymerizable compound (A), a monofunctional radically polymerizable compound (B), rubber particles (C), and a radical polymerization initiator (D) in appropriate amounts into a stirring vessel and stirring the mixture. If necessary, other component(s) (E) may be added. The stirring temperature is usually 20°C or higher and 120°C or lower, preferably 40°C or higher and 100°C or lower. The composition can be produced by removing volatile solvents and the like as necessary.

[0016] The photocurable resin composition according to the present invention is suitable as a modeling material used in stereolithography. When the photocurable resin composition of the present invention is used as a modeling material for stereolithography, the viscosity at a shear rate of 5s-1 and 25°C is preferably 0.050 Pa·s or more and 5.0 Pa·s or less, more preferably 0.075 Pa·s or more and 4.5 Pa·s or less, and still more preferably 0.075 Pa·s or more and 2.0 Pa·s or less.

[0017] Hereinafter, each component contained in the photocurable resin composition according to the present invention will be described in detail.

[0018] [Polyfunctional radical polymerizable compound (A)] The polyfunctional radical polymerizable compound (A) contained in the photocurable resin composition is a compound having multiple radical polymerizable functional groups within its molecule. Hereinafter, the polyfunctional radical polymerizable compound (A) may be simply referred to as compound (A).

[0019] The photocurable resin composition of the present invention includes, as compound (A), a polyfunctional urethane (meth)acrylate (a1) having at least two (meth)acryloyl groups and at least two urethane groups in its molecule, and having a structure represented by general formula (1) or (2).

[0020] [ka]

[0021] [ka]

[0022] In general formulas (1) and (2), R1 and R2 are each a hydrocarbon group containing an alkylene group having 1 to 18 carbon atoms, and n is 2 to 50. Preferably, it is a hydrocarbon group containing an alkylene group having 4 to 9 carbon atoms. R1 and R2 are -(CH2) m -(m=1~18), -(CH2) h C(CH3)2(CH2) i -(h=0~15,i=0~15), -(CH2) j CH(CH3)(CH2) k This includes any one or more selected from the group consisting of -(j=0~16, k=0~16). In particular, R1 and R2 each have -(CH2) m It is particularly preferable to include -(m=4~9). In addition, R1 and R2 may contain aromatic hydrocarbon groups in addition to alkylene groups.

[0023] For the polyfunctional urethane (meth)acrylate (a1), for example, a reaction product of a polyol compound, a hydroxyl group-containing (meth)acrylate compound, and a polyvalent isocyanate compound can be used. Alternatively, a reaction product of a polyol compound and an isocyanate group-containing (meth)acrylate compound, or a reaction product of a hydroxyl group-containing (meth)acrylate compound and a polyvalent isocyanate compound can also be used. A reaction product of a hydroxyl group-containing (meth)acrylate compound, a polyvalent isocyanate compound, and a polyol compound is preferred because it tends to easily achieve high impact resistance.

[0024] As the polyol compound, polycarbonate-based polyols or polyester-based polyols having the structure represented by the general formula (1) or (2) described above can be used. These may be used individually or in combination of multiple types. Polyfunctional urethane (meth)acrylate (a1) obtained using polycarbonate-based polyols or polyester-based polyols is preferred from the viewpoint of easily achieving both high elastic modulus and high impact strength. Polycarbonate-based polyols are particularly preferred over polyester-based polyols because they have stronger intermolecular interactions and tend to easily achieve a high elastic modulus without reducing impact strength.

[0025] Other polyol compounds include polyether polyols, polyolefin polyols, and (meth)acrylic polyols. These polyol compounds may be used in combination with polycarbonate polyols and / or polyester polyols.

[0026] When using a polycarbonate-based polyol or polyester-based polyol in combination with other polyol compounds, it is preferable that the polycarbonate-based polyol or polyester-based polyol is present in an amount of 20 parts by mass or more per 100 parts by mass of the total amount of polyol compounds. More preferably, it is present in an amount of 30 parts by mass or more. It is preferable that the polycarbonate-based polyol or polyester-based polyol is present in an amount of 20 parts by mass or more because it tends to make it easier to achieve both a high modulus of elasticity and high impact strength.

[0027] Polycarbonate-based polyols are compounds that have a carbonate bond in their molecule and hydroxyl groups at their terminals or side chains, and may also have ester bonds in addition to the carbonate bond. Examples of polycarbonate-based polyols include reaction products of polyhydric alcohols and phosgene, and ring-opening polymers of cyclic carbonate esters (such as alkylene carbonates).

[0028] Polyester polyols can be any compound that has an ester bond in its molecule and a hydroxyl group at its terminal or side chain. Examples include condensation polymers of polyhydric alcohols and polyhydric carboxylic acids, ring-opening polymers of cyclic esters (lactones), and reaction products of polyhydric alcohols and three components: polyhydric alcohols, polyhydric carboxylic acids, and cyclic esters.

[0029] Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3-trimethylenediol, 1,5-pentamethylenediol, neopentyl glycol, 1,6-hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylenediol, glycerin, trimethylolpropane, trimethylolethane, cyclohexanediols (such as 1,4-cyclohexanediol), bisphenols (such as bisphenol A), and sugar alcohols (such as xylitol and sorbitol).

[0030] Examples of the alkylene carbonates include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, and hexamethylene carbonate.

[0031] Examples of the polycarboxylic acids include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid, sebacic acid, and dodecanedionic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, and trimellitic acid.

[0032] Examples of the cyclic esters mentioned above include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone.

[0033] Examples of hydroxyl group-containing (meth)acrylate compounds include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate, 2-hydroxyethyl acryloyl phosphate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, dipropylene glycol (meth)acrylate, fatty acid-modified glycidyl (meth)acrylate, and polyethylene glycol mono(meth)acrylate. Examples include hydroxyl group-containing (meth)acrylate compounds, polypropylene glycol mono(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, glycerin di(meth)acrylate, 2-hydroxy-3-acryloyloxypropyl(meth)acrylate, pentaerythritol tri(meth)acrylate, caprolactone-modified pentaerythritol tri(meth)acrylate, ethylene oxide-modified pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, caprolactone-modified dipentaerythritol penta(meth)acrylate, and ethylene oxide-modified dipentaerythritol penta(meth)acrylate. These hydroxyl group-containing (meth)acrylate compounds may be used individually or in combination of two or more.

[0034] Examples of polyvalent isocyanate compounds include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate. Examples include aliphatic polyisocyanates such as cyanates and lysine triisocyanate, alicyclic polyisocyanates such as hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane, or trimer compounds or polymer compounds of these polyisocyanates, allophanate-type polyisocyanates, biuret-type polyisocyanates, and aqueous-dispersible polyisocyanates. These polyvalent isocyanate compounds may be used individually or in combination of two or more types.

[0035] Examples of isocyanate group-containing (meth)acrylate compounds include 2-isocyanatoethyl (meth)acrylate and 1,1-(bisacryloyloxymethyl)ethyl isocyanate. These isocyanate group-containing (meth)acrylate compounds may be used individually or in combination of two or more.

[0036] The weight-average molecular weight of the polyfunctional urethane (meth)acrylate (a1) in the photocurable resin composition is preferably 1,000 or more and 60,000 or less. More preferably, it is 2,000 or more and 50,000 or less. When the weight-average molecular weight is 1,000 or more, the impact resistance of the cured product tends to increase significantly with decreasing crosslinking density, and when the weight-average molecular weight is greater than 60,000, the viscosity of the curable composition tends to increase. In this invention, the notation "greater than or equal to" includes "greater than", and the notation "less than or equal to" includes "less than".

[0037] The weight-average molecular weight (Mw) of polyfunctional urethane (meth)acrylate (a1) is the weight-average molecular weight converted to the molecular weight of standard polystyrene. The weight-average molecular weight can be measured using high-performance liquid chromatography (HPC). For example, it can be measured using a Tosoh Corporation HLC-8220GPC high-performance GPC instrument with two Shodex GPCLF-804 columns in series (exclusion limit molecular weight: 2 × 10⁶, separation range: 300 to 2 × 10⁶).

[0038] Furthermore, it is preferable that the radical polymerizable functional group equivalent of the polyfunctional urethane (meth)acrylate (a1) is 300 g / eq or more. If the radical polymerizable functional group equivalent is less than 300 g / eq, the impact resistance tends to decrease as the crosslinking density increases. Note that the radical polymerizable functional group equivalent is a value that indicates the molecular weight per radical polymerizable functional group.

[0039] The content of polyfunctional urethane (meth)acrylate (a1) in the photocurable resin composition is 10 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B). Preferably, it is 15 parts by mass or more and 45 parts by mass or less. More preferably, it is 15 parts by mass or more and 40 parts by mass or less. By having the content of polyfunctional urethane (meth)acrylate (a1) within the above range, it is possible to achieve both high impact resistance and heat resistance. If the content of polyfunctional urethane (meth)acrylate (a1) is less than 10 parts by mass, the impact resistance tends to decrease significantly. Also, if the content of polyfunctional urethane (meth)acrylate (a1) is more than 60 parts by mass, the heat resistance decreases and the viscosity of the resin composition tends to be higher than the range suitable for photopolymerization materials.

[0040] The photocurable resin composition may contain one or more polyfunctional radical polymerizable compounds (a2) other than polyfunctional urethane (meth)acrylate (a1) as the polyfunctional radical polymerizable compound (A). Examples of radical polymerizable functional groups of the polyfunctional radical polymerizable compound (a2) contained in the photocurable resin composition include ethylenically unsaturated groups. Examples of ethylenically unsaturated groups include (meth)acryloyl groups and vinyl groups. Examples of polyfunctional radical polymerizable compounds (a2) include polyfunctional (meth)acrylate compounds, vinyl ether group-containing (meth)acrylate compounds, polyfunctional (meth)acryloyl group-containing isocyanurate compounds, polyfunctional (meth)acrylamide compounds, polyfunctional maleimide compounds, polyfunctional vinyl ether compounds, and polyfunctional aromatic vinyl compounds.

[0041] Examples of the aforementioned polyfunctional (meth)acrylate compounds include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, dimethylol tricyclodecane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, and 1,6 -Hexamethylene di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, di(meth)acrylate of ε-caprolactone adduct of hydroxypivalate neopentyl glycol (e.g., manufactured by Nippon Kayaku Co., Ltd., KAYARAD Examples include HX-220, HX-620, etc., di(meth)acrylates of EO adducts of bisphenol A, polyfunctional (meth)acrylates having fluorine atoms, polyfunctional (meth)acrylates having a siloxane structure, polycarbonate diol di(meth)acrylate, polyester di(meth)acrylate, polyethylene glycol di(meth)acrylate, polyether-based polyfunctional urethane (meth)acrylate, polyolefin-based polyfunctional urethane (meth)acrylate, and (meth)acrylic-based polyfunctional urethane (meth)acrylate.

[0042] Examples of vinyl ether group-containing (meth)acrylate compounds include 2-vinyloxyethyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, and 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate.

[0043] Examples of the polyfunctional (meth)acryloyl group-containing isocyanurate compounds include tri(acryloyloxyethyl)isocyanurate, tri(methacryloyloxyethyl)isocyanurate, and ε-caprolactone-modified tris-(2-acryloxyethyl)isocyanurate.

[0044] Examples of the aforementioned polyfunctional (meth)acrylamide compounds include N,N'-methylenebisacrylamide, N,N'-ethylenebisacrylamide, N,N'-(1,2-dihydroxyethylene)bisacrylamide, N,N'-methylenebismethacrylamide, and N,N',N''-triacryloyldiethylenetriamine.

[0045] Examples of the aforementioned polyfunctional maleimide compounds include 4,4'-diphenylmethanebismaleimide, m-phenylenebismaleimide, bisphenol A diphenyl etherbismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethanebismaleimide, 4-methyl-1,3-phenylenebismaleimide, and 1,6-bismaleimide-(2,2,4-trimethyl)hexane.

[0046] Examples of the aforementioned polyfunctional vinyl ether compounds include ethylene glycol divinyl ether, diethylene glycol divinyl ether, polyethylene glycol divinyl ether, propylene glycol divinyl ether, butylene glycol divinyl ether, hexanediol divinyl ether, bisphenol A alkylene oxide divinyl ether, bisphenol F alkylene oxide divinyl ether, trimethylolpropane trivinyl ether, ditrimethylolpropane tetravinyl ether, glycerin trivinyl ether, pentaerythritol tetravinyl ether, dipentaerythritol pentavinyl ether, and dipentaerythritol hexanyl ether.

[0047] Examples of the aforementioned polyfunctional aromatic vinyl compounds include divinylbenzene.

[0048] When the photocurable resin composition contains a polyfunctional radical polymerizable compound (a2) with a radical polymerizable functional group equivalent of less than 300 g / eq, its content is preferably 20 parts by mass or less per 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B). More preferably, it is 18 parts by mass or less, and even more preferably 15 parts by mass or less.

[0049] If the content of polyfunctional radical polymerizable compound (a2) with a radical polymerizable functional group equivalent of less than 300 g / eq is greater than 20 parts by mass, the crosslinking density of the cured product tends to increase, and at the same time, the crosslinking density tends to become non-uniform. As a result, when an external impact is applied, areas of stress concentration may occur, and the expected effect of improving impact resistance by adding rubber particles may not be obtained, resulting in a Charpy impact strength that is similar to that of conventional technology.

[0050] When the photocurable resin composition contains a polyfunctional radical polymerizable compound (a2) with a radical polymerizable functional group equivalent of 300 g / eq or more, the content of the polyfunctional radical polymerizable compound (a2) is preferably 40 parts by mass or less per 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B).

[0051] More preferably, the amount is 35 parts by mass or less. If the content of polyfunctional radical polymerizable compound (a2) with a radical polymerizable functional group equivalent of 300 g / eq or more is greater than 40 parts by mass, the heat resistance decreases, and at the same time, the elastic modulus of the resulting cured product tends to decrease significantly.

[0052] [Monofunctional radical polymerizable compound (B)] The monofunctional radical polymerizable compound (B) contained in the photocurable resin composition is a compound having only one radical polymerizable functional group in its molecule. Hereinafter, the monofunctional radical polymerizable compound (B) may be simply referred to as compound (B).

[0053] Examples of radically polymerizable functional groups include ethylenically unsaturated groups. Specific examples of ethylenically unsaturated groups include (meth)acryloyl groups and vinyl groups. In this specification, (meth)acryloyl group means either an acryloyl group or a methacryloyl group.

[0054] Examples of monofunctional radical polymerizable compounds (B) having a (meth)acryloyl group include monofunctional (meth)acrylamide compounds and monofunctional (meth)acrylate compounds.

[0055] Examples of monofunctional (meth)acrylamide compounds include (meth)acrylamide, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, N-phenyl(meth)acrylamide, N-methylol(meth)acrylamide, N,N-diacetone(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-dibutyl(meth)acrylamide, N-(meth)acryloylmorpholin, N-(meth)acryloylpiperidine, and N-[3-(dimethylamino)propyl]acrylamide.

[0056] Examples of monofunctional (meth)acrylate compounds include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, i-octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, and 2-hydroxyethyl (meth)acrylate. )Acrylate, 2-Hydroxypropyl (meth)acrylate, 2-Hydroxybutyl (meth)acrylate, 4-Hydroxybutyl (meth)acrylate, Glycidyl (meth)acrylate, 3-Methyl-3-Oxetanyl-methyl (meth)acrylate, Tetrahydrofurfuryl (meth)acrylate, Phenylglycidyl (meth)acrylate, Dimethylaminomethyl (meth)acrylate, Phenylcellosolve (meth)acrylate, Dicyclopentenyl (meth)acrylate, Dicyclopentenyloxyethyl (meth)acrylate, Bife Nyl (meth)acrylate, 2-hydroxyethyl (meth)acryloyl phosphate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, benzyl (meth)acrylate, butoxytriethylene glycol (meth)acrylate, 2-ethylhexyl polyethylene glycol (meth)acrylate, nonylphenyl polypropylene glycol (meth)acrylate, methoxydipropylene glycol (meth)acrylate, glycidyl (meth)acrylate, glycerol (meth)acrylate )Acrylate, trifluoromethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, allyl (meth)acrylate, epichlorohydrin-modified butyl (meth)acrylate, epichlorohydrin-modified phenoxy (meth)acrylate, ethylene oxide (EO)-modified phthalate (meth)acrylate, EO-modified succinate (meth)acrylate,Examples include caprolactone-modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, morpholino (meth)acrylate, EO-modified phosphate (meth)acrylate, methyl allyloxyacrylate (product name: AO-MA, manufactured by Nippon Shokubai Co., Ltd.), monofunctional (meth)acrylates having an imide group (product name: M-140, manufactured by Toagosei Co., Ltd.), and monofunctional (meth)acrylates having a siloxane structure.

[0057] Examples of monofunctional radical polymerizable compounds having ethylenically unsaturated groups other than (meth)acryloyl groups include styrene derivatives such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and its salts; maleimides such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, and cyclohexylmaleimide; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, and vinyl cinnamate; vinyl cyanide compounds such as (meth)acrylonitrile; and N-vinyl compounds such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, N-vinylimidazole, N-vinylmorpholine, N-vinylacetamide, and vinylmethyloxazolidinone.

[0058] These monofunctional radical polymerizable compounds may be used individually or in combination of two or more.

[0059] The amount of monofunctional radical polymerizable compound (B) contained in the photocurable resin composition is preferably 40 parts by mass or more and 85 parts by mass or less, based on 100 parts by mass of the total of polyfunctional radical polymerizable compound (A) and monofunctional radical polymerizable compound (B). More preferably, it is 45 parts by mass or more and 80 parts by mass or less.

[0060] From the viewpoint of accelerating the curing speed, it is preferable to include at least one compound selected from the group consisting of monofunctional acrylamide compounds, monofunctional acrylate compounds, and N-vinyl compounds as the monofunctional radical polymerizable compound. In particular, it is preferable to include a monofunctional acrylamide compound or an N-vinyl compound. Furthermore, since it tends to be easier to achieve both high heat resistance and high impact strength, it is preferable that the monofunctional acrylamide compound has a cyclic structure such as acryloylmorpholine or phenylacrylamide. In addition, it is preferable that the N-vinyl compound has a cyclic structure such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, N-vinylimidazole, N-vinylmorpholine, or vinylmethyloxazolidinone.

[0061] When an N-vinyl compound is used as the monofunctional radical polymerizable compound (B), it is preferable that the content of N-vinyl groups is 80 mol% or less relative to the total amount of radical polymerizable functional groups in the photocurable resin composition. More preferably, it is 75 mol% or less. N-vinyl compounds are difficult to homopolymerize, and by setting the content of N-vinyl groups to 80 mol% or less relative to the total amount of radical polymerizable functional groups, curing is significantly accelerated, making it suitable for use as a molding material in stereolithography, and therefore preferable.

[0062] When a monofunctional methacrylate compound is used as the monofunctional radical polymerizable compound (B), it is preferable that the methacrylate group content is 25 mol% or less relative to the total amount of radical polymerizable functional groups in the photocurable resin composition, as this tends to accelerate the curing rate. More preferably, the methacrylate group content is 20 mol% or less, or 0 mol%. If the methacrylate group content is greater than 20 mol%, the curing rate tends to decrease significantly, making it unsuitable as a molding material for stereolithography, and therefore undesirable.

[0063] Preferably, the photocurable resin composition does not contain a monofunctional radically polymerizable compound having an alicyclic hydrocarbon group, or when it contains the same, the content thereof is 50 parts by mass or less based on a total of 100 parts by mass of the polyfunctional radically polymerizable compound (A) and the monofunctional radically polymerizable compound (B). More preferably, the content is 40 parts by mass or less. If the content of the monofunctional radically polymerizable compound having an alicyclic hydrocarbon group is more than 50 parts by mass, the effect of improving impact resistance tends to be difficult to obtain. In addition, when the rubber particles (C) are added, the viscosity of the photocurable resin composition increases, which tends to make handling difficult. For example, when the photocurable resin composition is used as a modeling material for stereolithography, high viscosity may lead to prolonged modeling time or make the modeling itself difficult.

[0064] Examples of the monofunctional radically polymerizable compound having an alicyclic hydrocarbon group include isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, cyclohexyl (meth)acrylate, 4-t-butylcyclohexyl acrylate, 3,3,5-trimethylcyclohexyl acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, and the like.

[0065] The glass transition temperature (Tg) of the homopolymer or copolymer of the monofunctional radically polymerizable compound (B) is preferably 70°C or higher. More preferably, it is 80°C or higher. The Tg of a copolymer can be obtained by the FOX equation (equation (1)). The unit of Tg is absolute temperature. 1 / Tg=Σ(W i / Tg i )···Equation (1)

[0066] In the above formula (1), W i is the mass ratio of each monofunctional radically polymerizable compound in the copolymer. Tg i is the glass transition temperature (unit: absolute temperature) of the homopolymer of each monofunctional radically polymerizable compound. The glass transition temperature (Tgi For each polymer, generally known values ​​can be used. Alternatively, the polymers can be actually fabricated, and experimental values ​​obtained by differential scanning calorimetry (DSC) or dynamic viscoelasticity measurement (DMA) can be used.

[0067] [Rubber particles (C)] By incorporating rubber particles (C) into a photocurable resin composition, the impact resistance of the cured product can be improved.

[0068] The composition constituting the rubber particles contained in the photocurable resin composition is a diene compound. Examples of rubber particles composed of diene compounds include butadiene rubber, crosslinked butadiene rubber, styrene / butadiene copolymer rubber, acrylonitrile / butadiene copolymer rubber, isoprene rubber, chloroprene rubber, and natural rubber. The rubber particles are preferably composed of these compositions individually or in combination of two or more. In particular, from the viewpoint of improving impact resistance and suppressing the increase in viscosity of the photocurable resin composition, rubber particles containing any one selected from the group consisting of butadiene rubber, crosslinked butadiene rubber, and styrene / butadiene copolymer rubber are preferred.

[0069] The glass transition temperature of the rubber particle composition is preferably 0°C or lower, more preferably -5°C or lower. If the glass transition temperature is higher than 0°C, it tends to be difficult to obtain an improved impact resistance. The glass transition temperature of the rubber particle composition can be determined, for example, by differential scanning calorimetry (DSC) or dynamic viscoelasticity measurement (DMA).

[0070] It is more preferable that the rubber particles have a core-shell structure. Specifically, it is preferable that the rubber particles have a core containing the aforementioned rubber, and further have a shell made of a polymer of a radically polymerizable compound that covers the outside (surface) thereof. By using rubber particles with a core-shell structure, the dispersibility of the rubber particles in the resin composition can be moderately improved, and the impact resistance can be further improved.

[0071] The polymer of the radical polymerizable compound that forms the shell is preferably graft polymerized onto the surface of the core via chemical bonds, and has a form that covers at least a portion of the core. Rubber particles having a core-shell structure in which the shell is graft polymerized onto the core can be formed by graft polymerizing a radical polymerizable compound in the presence of core particles using known methods. For example, they can be produced by adding a radical polymerizable compound, which is a component of the shell, to latex particles dispersed in water, which can be prepared by emulsion polymerization, miniemulsion polymerization, suspension polymerization, seed polymerization, etc., and polymerizing them.

[0072] Furthermore, if there are no or very few reactive sites, such as ethylenically unsaturated groups, on the surface of the core that can be graft-polymerized by the shell, an intermediate layer containing reactive sites may be provided on the surface of the core particle before graft-polymerizing the shell. In other words, the form of rubber particles having a core-shell structure also includes a form in which the shell is provided on the core via an intermediate layer.

[0073] As the radical polymerizable compound that forms the shell, a monofunctional radical polymerizable compound having one radical polymerizable functional group in its molecule can be suitably used. Rubber particles having a shell containing a polymer of the monofunctional radical polymerizable compound exhibit excellent dispersibility when dispersed in a resin composition containing the radical polymerizable compound. They are also preferable because they tend to easily provide high impact resistance.

[0074] The monofunctional radical polymerizable compound used to form the shell can be appropriately selected considering its compatibility with the core composition and its dispersibility in the resin composition. For example, one or more materials from the examples provided as monofunctional radical polymerizable compound (B) may be used in combination. It is preferable that the shell contains a polymer of a monofunctional radical polymerizable compound having a (meth)acryloyl group, as this tends to result in good dispersibility of rubber particles in the photocurable resin composition and suppress an increase in the viscosity of the photocurable resin composition.

[0075] Furthermore, a monofunctional radical polymerizable compound and a polyfunctional radical polymerizable compound may be used in combination as the radical polymerizable compound for forming the shell. When a polyfunctional radical polymerizable compound is used to form the shell, the viscosity of the photocurable resin composition tends to decrease, making it easier to handle. On the other hand, if the content of the polyfunctional radical polymerizable compound is excessive, it tends to become difficult to obtain the effect of improving impact resistance by adding rubber particles having a core-shell structure. Therefore, when a polyfunctional radical polymerizable compound is used for shell formation, it is preferable that the polyfunctional radical polymerizable compound is 40 parts by mass or less per 100 parts by mass of the radical polymerizable compound used for shell formation. More preferably, it is 30 parts by mass or less, and even more preferably 25 parts by mass or less. The polyfunctional radical polymerizable compound used for shell formation can be appropriately selected considering its compatibility with the composition constituting the core and its dispersibility in the resin composition. One or more materials from the examples of polyfunctional urethane (meth)acrylate (a1) and polyfunctional radical polymerizable compound (a2) may be used in combination.

[0076] In rubber particles having a core-shell structure, the mass ratio of core to shell is preferably 1 to 200 parts by mass of shell per 100 parts by mass of core, and more preferably 2 to 180 parts by mass of shell. If the mass ratio of core to shell is within the above range, it is possible to effectively improve impact resistance by adding it to a photocurable resin composition. If the amount of shell is less than 1 part by mass, the dispersibility of the rubber particles in the photocurable resin composition is insufficient, and the effect of improving impact resistance tends to be difficult to obtain. If the amount of shell is more than 200 parts by mass, the rubber particles are thickly covered by the shell, and the effect of improving impact resistance by the rubber component is reduced. In order to obtain sufficient impact resistance, it is necessary to add a large amount of rubber particles, and when a large amount of rubber particles are added, the viscosity of the photocurable resin composition tends to increase, making it difficult to handle.

[0077] The rubber particles preferably have an average particle diameter of 20 nm to 10 μm, and more preferably 50 nm to 5 μm. If the average particle diameter is less than 20 nm, the viscosity of the photocurable resin composition increases with the addition of the rubber particles, and the interaction between the rubber particles, which occurs due to the increase in the specific surface area of ​​the rubber particles, tends to cause a decrease in the heat resistance and impact resistance of the cured product.

[0078] When the average particle diameter is greater than 10 μm, the surface area (specific surface area) of the interface between the rubber particles (rubber components) and the cured product of the photocurable resin composition decreases drastically, which tends to reduce the effect of adding rubber particles on improving impact resistance. The average particle diameter referred to here is the arithmetic (number) mean particle diameter, which can be measured using dynamic light scattering. For example, rubber particles can be dispersed in a suitable organic solvent and measured using a particle size analyzer.

[0079] Furthermore, the gel fraction of the rubber particles is preferably 5% or more. If the gel fraction is less than 5%, both impact resistance and heat resistance tend to decrease, which is undesirable. The gel fraction can be determined by the following procedure. Immerse dried rubber particles W1 [g] in a sufficient amount of toluene and leave it at room temperature for 7 days. Then, remove the solids by centrifugation or the like and dry them at 100°C for 2 hours, and measure the amount of solids obtained after drying. If the mass of the solids obtained after drying is W2 [g], it can be calculated by the following formula. Gel fraction (%) = W2 / W1 × 100

[0080] The rubber particle content in the photocurable resin composition shall be 2 parts by mass or more and less than 18 parts by mass per 100 parts by mass of the total radical polymerizable compounds. Preferably, it shall be 3 parts by mass or more and 16 parts by mass or less. If the rubber particle content is less than 2 parts by mass, the effect of improving impact resistance due to the addition of rubber particles will not be obtained. If the rubber particle content is 18 parts by mass or more, the elastic modulus of the resulting cured product will decrease significantly. In addition, because the rubber particles are in close proximity to each other, the interaction will increase, the viscosity of the photocurable resin composition will increase significantly, and it will become difficult to handle.

[0081] [Radical polymerization initiator (D)] The radical polymerization initiator (D) can be a photo-radical polymerization initiator or a thermal radical polymerization initiator.

[0082] Photoradical polymerization initiators are mainly classified into intramolecular cleavage type and hydrogen abstraction type. In intramolecular cleavage type photoradical polymerization initiators, absorption of light of a specific wavelength breaks bonds at specific sites, generating radicals at the broken sites. These radicals act as polymerization initiators, initiating the polymerization of ethylenically unsaturated compounds containing (meth)acryloyl groups. On the other hand, in the case of hydrogen abstraction type initiators, absorption of light of a specific wavelength leads to an excited state, and these excited species undergo hydrogen abstraction reactions from surrounding hydrogen donors, generating radicals. These radicals act as polymerization initiators, initiating the polymerization of radically polymerizable compounds.

[0083] Known intramolecular cleavage-type photoradical polymerization initiators include alkylphenone-based photoradical polymerization initiators, acylphosphine oxide-based photoradical polymerization initiators, and oxime ester-based photoradical polymerization initiators. These are of the type in which a bond adjacent to the carbonyl group undergoes α-cleavage to generate a radical species. Examples of alkylphenone-based photoradical polymerization initiators include benzylmethyl ketal-based photoradical polymerization initiators, α-hydroxyalkylphenone-based photoradical polymerization initiators, and aminoalkylphenone-based photoradical polymerization initiators. Specific compounds include, for example, benzyl methyl ketal-based photoradical polymerization initiators such as 2,2'-dimethoxy-1,2-diphenylethane-1-one (Irgacure® 651, manufactured by BASF), and α-hydroxyalkylphenone-based photoradical polymerization initiators such as 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocure 1173, manufactured by BASF), 1-hydroxycyclohexylphenyl ketone (Irgacure 184, manufactured by BASF), and 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (Irgacure® 651). Examples include Irgacure 2959 (manufactured by BASF) and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methylpropionyl)benzyl]phenyl}-2-methylpropan-1-one (Irgacure 127, manufactured by BASF). Aminoalkylphenone-based photoradical polymerization initiators include, but are not limited to, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (Irgacure 907, manufactured by BASF) or 2-benzylmethyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (Irgacure 369, manufactured by BASF). Examples of acylphosphine oxide-based photoradical polymerization initiators include, but are not limited to, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucilin TPO, manufactured by BASF) and bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819, manufactured by BASF).Examples of oxime ester-based photoradical polymerization initiators include (2E)-2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]octan-1-one (Irgacure OXE-01, manufactured by BASF), but are not limited to these. Examples of trade names are listed in parentheses.

[0084] Examples of the hydrogen abstraction-type radical polymerization initiators include, but are not limited to, anthraquinone derivatives such as 2-ethyl-9,10-anthraquinone and 2-t-butyl-9,10-anthraquinone, and thioxanthone derivatives such as isopropylthioxanthone and 2,4-diethylthioxanthone. These photoradical polymerization initiators may be used alone or in combination of two or more types. They may also be used in combination with the thermal radical polymerization initiators described later.

[0085] The amount of photoradical polymerization initiator added is preferably 0.1 parts by mass or more and 15 parts by mass or less per 100 parts by mass of the radical polymerizable compound contained in the photocurable resin composition.

[0086] More preferably, the amount is 0.1 parts by mass or more and 10 parts by mass or less. If the amount of photoradical polymerization initiator is too small, polymerization tends to be insufficient. If an excess of polymerization initiator is added, the molecular weight will not increase, and there is a risk that the heat resistance or impact resistance will decrease. Here, the radical polymerizable compound is a combination of a polyfunctional radical polymerizable compound (A) and a monofunctional radical polymerizable compound (B).

[0087] Furthermore, the thermal radical polymerization initiator is not particularly limited as long as it generates radicals upon heating, and conventionally known compounds can be used. For example, azo compounds, peroxides, and persulfates are preferred examples. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(methylisobutyrate), 2,2'-azobis-2,4-dimethylvaleronitrile, and 1,1'-azobis(1-acetoxy-1-phenylethane). Examples of peroxides include benzoyl peroxide, di-t-butylbenzoyl peroxide, t-butyl peroxypivalate, and di(4-t-butylcyclohexyl)peroxydicarbonate. Examples of persulfates include ammonium persulfate, sodium persulfate, and potassium persulfate.

[0088] The amount of thermal radical polymerization initiator added is preferably 0.1 parts by mass to 15 parts by mass, and more preferably 0.1 parts by mass to 10 parts by mass, per 100 parts by mass of the radical polymerizable compound contained in the photocurable resin composition. Adding an excess of polymerization initiator may prevent an increase in molecular weight and may reduce heat resistance or impact resistance.

[0089] [Other ingredients (E)] The photocurable resin composition may contain other components (E) to the extent that it does not impair the objectives and effects of the present invention.

[0090] Other components (E) may include property modifiers, photosensitizers, polymerization initiators, leveling agents, wettability modifiers, surfactants, plasticizers, UV absorbers, and silane coupling agents to impart desired properties to the cured product. Alternatively, it may include inorganic fillers, pigments, dyes, antioxidants, flame retardants, thickeners, defoamers, etc.

[0091] The amount of other component (E) added is preferably 0.05 parts by mass or more and 25 parts by mass or less, based on 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B). More preferably, it is 0.1 parts by mass or more and 20 parts by mass or less. Within this range, desired physical properties can be imparted to the cured product or photocurable resin composition without reducing the elastic modulus or impact resistance of the resulting cured product.

[0092] For example, as a property modifier to impart desired physical properties to a cured product, resins such as epoxy resin, polyurethane, polychloroprene, polyester, polysiloxane, petroleum resin, xylene resin, ketone resin, cellulose resin, or polycarbonate, modified polyphenylene ether, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, ultra-high molecular weight polyethylene, polyphenylsulfone, polysulfone, polyarylate, polyetherimide, polyetheretherketone, polyphenyl Examples include engineering plastics such as polysulfides, polyethersulfones, polyamide-imides, liquid crystal polymers, polytrafluoroethylenes, polychlorotrifluoroethylenes, and polyvinylidene fluoride; fluorine-based oligomers, silicone-based oligomers, and polysulfide-based oligomers; soft metals such as gold, silver, and lead; and layered crystalline materials such as graphite, molybdenum disulfide, tungsten disulfide, boron nitride, graphite fluoride, calcium fluoride, barium fluoride, lithium fluoride, silicon nitride, and molybdenum selenide.

[0093] Furthermore, examples of photosensitizers include phenothiazines, polymerization inhibitors such as 2,6-di-t-butyl-4-methylphenol, benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, tertiary amine compounds, and xanthone compounds.

[0094] <Method of manufacturing articles> As a method for curing the photocurable resin composition according to the present invention to obtain an article, known stereolithography methods can be suitably used. A typical example of a preferred stereolithography method is a method that has a step of repeatedly curing the photocurable resin composition to a predetermined thickness based on slice data generated based on three-dimensional shape data of the object to be manufactured (three-dimensional model). Stereolithography methods can be broadly divided into two types: free-level method and controlled-level method.

[0095] Figure 1 shows an example configuration of a stereolithography apparatus 100 using the free-level method. The stereolithography apparatus 100 has a tank 11 that contains a liquid photocurable resin composition 10. Inside the tank 11, a molding stage 12 is provided so as to be drivable vertically by a drive shaft 13. Light energy rays 15 for curing the photocurable resin composition 10, ejected from a light source 14, have their irradiation position changed by a galvanometer mirror 16 controlled by a control unit 18 according to slice data, and scan the surface of the photocurable resin composition 10. In Figure 1, the scanning range is shown by a thick dashed line.

[0096] The thickness d of the photocurable resin composition 10 cured by the light energy rays 15 is a value determined based on the settings when generating the slice data, and affects the accuracy of the resulting article (reproducibility of the three-dimensional shape data of the article being fabricated). The thickness d is achieved by the control unit 18 controlling the amount of drive of the drive shaft 13.

[0097] First, the control unit 18 controls the drive shaft 13 based on the settings, and a photocurable resin composition is supplied onto the stage 12 in a thickness d. Based on slice data, light energy rays are selectively irradiated onto the liquid photocurable resin composition on the stage 12 to form a cured layer having a desired pattern. Next, by moving the stage 12 in the direction of the white arrow, an uncured photocurable resin composition is supplied to the surface of the cured layer in a thickness d. Then, based on slice data, light energy rays 15 are irradiated, and a cured product is formed that is integrated with the previously formed cured layer. By repeating this layered curing process, the desired three-dimensional object can be obtained.

[0098] When forming a cured layer with a predetermined shape pattern by irradiating a surface made of a photocurable resin composition with active energy rays, the resin can be cured in a pointillist or linear manner by using light energy rays focused into a point or linear shape. Alternatively, the resin may be cured by irradiating it in a planar manner with active energy rays through a planar drawing mask formed by arranging multiple minute light shutters such as liquid crystal shutters or digital micromirror shutters.

[0099] Similar to the free-level method, the controlled-level method is also preferred for fabrication. In a stereolithography apparatus using the controlled-level method, the stage 12 of the stereolithography apparatus 100 in Figure 1 is positioned to pull the fabricated object above the liquid level, and the light irradiation means is positioned below the tank 11. A typical example of fabrication using the controlled-level method is as follows: First, a support stage, which is provided to be vertically movable, is set up so that its support surface and the bottom surface of a tank containing a photocurable resin composition are at a predetermined distance from each other, and the photocurable resin composition is supplied between the support surface of the support stage and the bottom surface of the tank. Next, from the bottom side of the tank containing the photocurable resin composition, light is selectively irradiated onto the photocurable resin composition between the stage support surface and the bottom surface of the tank according to the slice data using a laser light source or projector. The photocurable resin composition between the stage support surface and the bottom surface of the tank hardens due to the light irradiation, forming a solid hardened layer. After that, the hardened layer is peeled off the bottom surface of the tank by raising the support stage.

[0100] Next, the height of the support stage is adjusted so that there is a predetermined distance between the cured layer formed on the support stage and the bottom surface of the tank. Then, as before, a photocurable resin composition is supplied between the bottom surface of the tank and the cured layer, and light is irradiated according to the slice data to form a new cured layer between the photocured layer and the bottom surface of the tank. By repeating this process multiple times, a molded object 17 can be obtained in which multiple cured layers are integrally laminated.

[0101] The molded object obtained in this way can be removed from the tank 11, and any unreacted photocurable resin composition remaining on its surface can be removed. After that, the desired article can be obtained by performing post-processing as necessary.

[0102] Post-processing includes cleaning, post-curing, cutting, polishing, and assembly.

[0103] As cleaning agents, alcohol-based organic solvents such as isopropyl alcohol and ethyl alcohol can be used. Alternatively, ketone-based organic solvents such as acetone, ethyl acetate, and methyl ethyl ketone, or aliphatic organic solvents such as terpenes may be used.

[0104] After cleaning, post-curing may be performed by light irradiation, heat irradiation, or both, as needed. Post-curing can cure any unreacted photocurable resin composition that may remain on the surface and inside the printed object, reducing stickiness on the surface of the three-dimensional object and improving the initial strength of the object.

[0105] Examples of light energy rays used in the manufacture of three-dimensional objects include ultraviolet rays, electron beams, X-rays, and radiation. Among these, ultraviolet rays with wavelengths between 300 nm and 450 nm are preferred from an economic standpoint. Light sources that generate ultraviolet rays include ultraviolet lasers (e.g., Ar lasers, He-Cd lasers), mercury lamps, xenon lamps, halogen lamps, and fluorescent lamps. Among these, laser light sources are preferred because they have excellent focusing properties, can increase the energy level to shorten the manufacturing time, and can achieve high manufacturing accuracy. [Examples]

[0106] The following describes examples of the present invention, but the present invention is not limited to these examples.

[0107] <Materials used> The materials used in the examples and comparative examples are listed below.

[0108] [Polyfunctional radical polymerizable compound (A)] (Polyfunctional urethane (meth)acrylate (a1)) a1-1: Polycarbonate-based urethane acrylate; "CN9001NS" (Arkema, difunctional, number-average molecular weight / weight-average molecular weight (measured value): 1.3 × 10⁻⁶) 3 / 5.4×10 3 a1-2: Polyester-based urethane acrylate; "KAYARAD UXT-6100" (manufactured by Nippon Kayaku Co., Ltd., difunctional, number average molecular weight / weight average molecular weight (measured value): 2.7 × 10⁻⁶) 3 / 6.0×10 3 ) ((a1) Other polyfunctional radical polymerizable compounds (a2)) a2-1: Polyether-based urethane acrylate; "KAYARAD UX-6101" (difunctional, number average molecular weight / weight average molecular weight (measured value): 1.0 × 10⁻⁶) 3 / 6.7×10 3 (Radical polymerizable functional group equivalent: 500g / eq, manufactured by Nippon Kayaku Co., Ltd.) a2-2: Ethoxylated isocyanuric acid triacrylate "A-9300" (Molecular weight: 423, Radical polymerizable functional group equivalent: 141 g / eq, manufactured by Shin Nakamura Chemical Industry Co., Ltd.) a2-3: Polycarbonate diol diacrylate "UM-90(1 / 3)DM" (Molecular weight: approx. 900, Radical polymerizable functional group equivalent: approx. 450 g / eq, Manufactured by Ube Industries, Ltd.)

[0109] [Monofunctional radical polymerizable compound (B)] B-1: N-vinyl-ε-caprolactam B-2: Acryloylmorpholine; "ACMO" (manufactured by KJ Chemicals) B-3: Diacetone acrylamide; "DAAM" (manufactured by KJ Chemicals) B-4: Vinylmethyloxazolidinone; "VMOX" (manufactured by BASF) B-5: Isobornyl acrylate

[0110] [Rubber particles (C)] C-1: Kaneace M-511 (manufactured by Kaneka Corporation); rubber particles with a core-shell structure consisting of a cross-linked butadiene rubber core and a polymethyl methacrylate shell. C'-1: Metabrene W-600A (manufactured by Mitsubishi Chemical Corporation); rubber particles with a core-shell structure consisting of an acrylic rubber core and a polymethyl methacrylate shell.

[0111] Acetone dispersions of rubber particles C-1 and C'-1 were prepared by the following method.

[0112] (Production of acetone dispersion of rubber particles C-1) A dispersion of core-shell type rubber particles C-1 was obtained by mixing 20 parts by mass of rubber particles C-1 and 80 parts by mass of acetone, and then dispersing the mixture using an ultrasonic homogenizer until it became primary particles. The average particle size of the core-shell type rubber particles C-1, measured using dynamic light scattering, was 0.23 μm.

[0113] (Preparation of acetone dispersion of rubber particles C'-1) A dispersion of core-shell type rubber particles C'-1 was obtained by mixing 20 parts by mass of rubber particles C'-1 with 80 parts by mass of acetone and dispersing the mixture using an ultrasonic homogenizer until it became primary particles. The average particle size of core-shell type rubber particles C'-1, measured using dynamic light scattering, was 0.36 μm.

[0114] [Radical polymerization initiator (D)] D-1: Photoradical generator; "Irgacure819" (manufactured by BASF) <Manufacturing of photocurable resin compositions> Each material was blended according to the mixing ratios shown in Table 1 and mixed until uniform. An acetone dispersion of rubber particles C-1 or C'-1 was added to this mixture, and the volatile acetone was removed to obtain the photocurable resin compositions of Examples 1-8 and Comparative Examples 1-6.

[0115] <Preparation of test specimens> A cured product was prepared from the prepared photocurable resin composition using the following method. First, a mold measuring 80 mm in length, 10 mm in width, and 4 mm in thickness was placed between two sheets of quartz glass, and the photocurable resin composition was poured into it. The poured photocurable resin composition was irradiated with ultraviolet light at 5 mW / cm2 from both sides of the mold alternately for 180 seconds each, twice, using an ultraviolet irradiation device (HOYA CANDEO OPTRONICS, product name "LIGHT SOURCE EXECURE3000"). The resulting cured product was heat-treated in a 70°C oven for 2 hours to obtain a test specimen measuring 80 mm in length, 10 mm in width, and 4 mm in thickness.

[0116] <Rating> [Weight average molecular weight] Two Shodex GPC LF-804 columns (Showa Denko Corporation, exclusion limit molecular weight: 2 × 10⁶, separation range: 300 to 2 × 10⁶) were placed in series in a gel permeation chromatography (GPC) apparatus (Tosoh Corporation, HLC-8220GPC). The molecular weight was measured at 40°C using THF as the developing solvent and with a RI (Refractive Index) detector. The obtained weight-average molecular weight is the value on a standard polystyrene basis.

[0117] [Average particle size of rubber particles] Using a particle size analyzer (Malvern Zetasizer Nano ZS), approximately 1 ml of a dilute acetone dispersion of rubber particles (C-1, C-2) was placed in a glass cell, and the average particle size (Z-Average) was measured at 25°C.

[0118] [Viscosity of photocurable resin compositions] The viscosity of the photocurable resin composition was measured using a rotational rheometer. Specifically, it was measured using a viscoelasticity analyzer (Physica MCR302, manufactured by Anton Paar) as follows.

[0119] A measuring device fitted with a cone-plate type measuring jig (CP25-2, manufactured by Anton Paar; 25 mm diameter, 2°) was filled with approximately 0.5 mL of the sample and adjusted to 25°C. Under a constant shear rate condition of 5 s⁻¹, measurements were taken at a data interval of 6 seconds, and the value at 120 seconds was defined as viscosity. Viscosity was evaluated according to the following criteria. Samples with an evaluation of A or B have a viscosity suitable for stereolithography, while samples with a C have a viscosity that is too high and are not suitable for stereolithography. A: Viscosity is 2.0 Pa·s or less B: Viscosity greater than 2.0 Pa·s and 5.0 Pa·s or less C: Viscosity greater than 5.0 Pa·s

[0120] [Temperature of deflection under load] For the test specimens, a load deflection temperature testing machine (manufactured by Toyo Seiki Seisakusho, product name "No. 533 HDT Test Apparatus 3M-2") was used in accordance with JIS K 7191-2, and the temperature was increased from room temperature at 2°C per minute under a bending stress of 1.80 MPa. The temperature at which the deflection of the test specimen reached 0.34 mm was defined as the load deflection temperature and used as an indicator of heat resistance. The obtained results are shown in Table 1. Heat resistance was evaluated according to the following criteria. Evaluations A and B indicate load deflection temperatures that are suitable for use in actual products, while evaluation C indicates a low load deflection temperature and is unsuitable for actual products. A: Load deflection temperature is 70°C or higher B: Load deflection temperature is between 50°C and 70°C C: Load deflection temperature is less than 50°C

[0121] [Charpy impact strength] In accordance with JIS K 7111, a 2mm deep, 45° notch was made in the center of the test specimen using a notching machine (manufactured by Toyo Seiki Seisakusho, product name "Notching Tool A-4"). An impact tester (manufactured by Toyo Seiki Seisakusho, product name "IMPACT TESTER IT") was used to fracture the test specimen from the back of the notch with an energy of 2J. The energy required for fracture was calculated from the angle at which the hammer, swung up to 150°, rose after the test specimen fractured, and this was defined as the Charpy impact strength, which was used as an indicator of impact resistance. The results obtained are shown in Table 1. Impact resistance was evaluated according to the following criteria: A rating was given for Charpy impact strength significantly exceeding that of conventional photocurable compositions, and a rating of B was given for Charpy impact strength exceeding that of conventional photocurable compositions. A rating of C was given for Charpy impact strength equal to or less than that of conventional photocurable compositions. A: Charpy impact strength is 10kJ / m2 or higher B: Charpy impact strength between 7kJ / m2 and less than 10kJ / m2 C: Charpy impact strength less than 7kJ / m2

[0122] [Flexural modulus] As an evaluation of the mechanical properties, a bending test was performed in accordance with JIS K6911-1995 "General Test Methods for Thermosetting Plastics" to measure the flexural modulus. A tensile testing machine (manufactured by A&D Company, Limited, product name "Tensilon Universal Material Testing Machine RTF-1250") was used for the measurement. The modulus was evaluated according to the following criteria. Materials with an evaluation of A or B showed a flexural modulus equivalent to or higher than general-purpose ABS, while materials with an evaluation of C had a flexural modulus lower than ABS. A: Flexural modulus of elasticity of 2.2 GPa or higher B: Flexural modulus of elasticity is 1.7 GPa or more and less than 2.2 GPa C: Flexural modulus less than 1.7 GPa

[0123] [Table 1]

[0124] As shown in Table 1, the photocurable resin compositions prepared in Examples 1 to 17 had viscosities within a suitable range for use as molding materials in stereolithography. Furthermore, the resulting cured products exhibited high elastic modulus, as well as excellent impact resistance and heat resistance.

[0125] The cured product of Comparative Example 1, obtained from a photocurable resin composition containing only polyether-based urethane acrylate and no polycarbonate-based urethane acrylate, did not show a significant difference in impact strength compared to the cured product of Example 1. However, both the elastic modulus and heat resistance were lower. The cured product of Comparative Example 2, obtained from a photocurable resin composition with a high rubber particle (C) content of 18.5 parts by mass, had extremely high viscosity and was unsuitable for molding using stereolithography. The cured product of Comparative Example 3, obtained from a photocurable resin composition with a low rubber particle (C) content of 1.5 parts by mass, did not show sufficient improvement in impact resistance.

[0126] The photocurable resin composition containing acrylic rubber particles had extremely high viscosity, making it difficult to use for 3D printing. Furthermore, Comparative Example 4, which was the cured product of this composition, had low load deflection temperature and flexural modulus.

[0127] Comparative Example 5, which did not contain rubber particles (C), and Comparative Example 6, which did not contain polycarbonate-based urethane acrylate, both exhibited low impact resistance.

[0128] The cured product according to Comparative Example 7, obtained from a photocurable resin composition containing 18 parts by mass or more of rubber particles (C), had both low flexural modulus and high viscosity.

[0129] Comparative Example 8, obtained from a photocurable resin mixture in which the content of polyfunctional urethane (meth)acrylate (a1) was less than 10 parts by mass per 100 parts by mass of the total amount of polyfunctional radical polymerizable compound (A) and monofunctional radical polymerizable compound (B), exhibited low impact resistance. Conversely, Comparative Example 9, obtained from a photocurable resin mixture in which the content of polyfunctional urethane (meth)acrylate (a1) exceeded 60 parts by mass, exhibited reduced heat resistance.

[0130] From the above results, it has been confirmed that the present invention provides a photocurable resin composition with a viscosity suitable for stereolithography, and that cured products with high elastic modulus, good impact resistance, and heat resistance can be obtained by curing it.

Claims

1. A polyfunctional radical polymerizable compound (A), Monofunctional radical polymerizable compound (B), Rubber particles (C) made of diene compounds, A photocurable resin composition comprising a radical polymerization initiator (D), The polyfunctional radical polymerizable compound (A) is a reaction product of a polyol compound, a hydroxyl group-containing (meth)acrylate compound, and a polyvalent isocyanate compound, or a reaction product of a polyol compound and an isocyanate group-containing (meth)acrylate compound, wherein the polyol compound has at least two (meth)acryloyl groups and two urethane groups in its molecule, and the polyol compound contains a polyfunctional urethane (meth)acrylate (a1) having a structure represented by general formula (1) or (2). The content of the polyfunctional urethane (meth)acrylate (a1) relative to 100 parts by mass of the total amount of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B) is It is 10 parts by mass or more and 60 parts by mass or less. A photocurable resin composition characterized in that the content of the rubber particles (C) is 2 parts by mass or more and less than 18 parts by mass relative to 100 parts by mass of the total amount of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B). 【Chemistry 1】 （１） 【Chemistry 2】 （２） [R in general formulas (1) and (2)] １ , R ２ Each of these is a hydrocarbon group containing an alkylene group having 1 to 18 carbon atoms, and n is 2 to 50.

2. The photocurable resin composition according to claim 1, characterized in that the content of the polyfunctional urethane (meth)acrylate (a1) is 15 parts by mass or more and 45 parts by mass or less per 100 parts by mass of the total amount of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B).

3. In the above general formulas (1) and (2), each of R1 and R2 is -(CH ２ ) ｍ -(m=1 to 18), -(CH ２ ) ｈ C(CH ３ ) ２ (CH ２ ) ｉ -(h=0 to 15, i=0 to 15), -(CH ２ ) ｊ CH(CH ３ )(CH ２ ) ｋ -(j=0 to 16, k=0 to 16), which is any one selected from the group consisting of, or a combination of two or more selected from the group consisting of. The photocurable resin composition according to claim 1 or 2, characterized in that:

4. In the above general formulas (1) and (2), R １ and R ２ Each of them is - (CH ２ ) ｍ The photocurable resin composition according to claim 3, characterized by containing - (m = 4 to 9).

5. The photocurable resin composition according to any one of claims 1 to 4, characterized in that the weight-average molecular weight of the polyfunctional urethane (meth)acrylate (a1) on a standard polystyrene molecular weight basis is 1,000 or more and 60,000 or less.

6. The photocurable resin composition according to claim 5, characterized in that the weight-average molecular weight of the polyfunctional urethane (meth)acrylate (a1) on a standard polystyrene molecular weight basis is 2,000 or more and 50,000 or less.

7. The photocurable resin composition according to any one of claims 1 to 6, characterized in that the radical polymerizable functional group equivalent of the polyfunctional urethane (meth)acrylate (a1) is 300 g / eq or more.

8. The photocurable resin composition according to any one of claims 1 to 7, characterized in that the polyfunctional radical polymerizable compound (A) includes a polyfunctional radical polymerizable compound (a2) other than the polyfunctional urethane (meth)acrylate (a1).

9. The photocurable resin composition according to claim 8, characterized in that the polyfunctional radical polymerizable compound (a2) has an ethylenically unsaturated group.

10. The photocurable resin composition according to claim 9, characterized in that the polyfunctional radical polymerizable compound (a2) includes at least one selected from the group consisting of polyfunctional (meth)acrylate compounds, vinyl ether group-containing (meth)acrylate compounds, polyfunctional (meth)acryloyl group-containing isocyanurate compounds, polyfunctional (meth)acrylamide compounds, polyfunctional maleimide compounds, polyfunctional vinyl ether compounds, and polyfunctional aromatic vinyl compounds.

11. The photocurable resin composition according to any one of claims 8 to 10, characterized in that, when the polyfunctional radical polymerizable compound (a2) includes a compound with a radical polymerizable functional group equivalent of less than 300 g / eq, its content is 20 parts by mass or less with respect to 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B).

12. The photocurable resin composition according to any one of claims 8 to 11, characterized in that, when the polyfunctional radical polymerizable compound (a2) contains a compound with a radical polymerizable functional group equivalent of 300 g / eq or more, its content is 40 parts by mass or less with respect to 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B).

13. The photocurable resin composition according to any one of claims 1 to 12, characterized in that the content of the monofunctional radical polymerizable compound (B) is 40 parts by mass or more and 85 parts by mass or less with respect to 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B).

14. The photocurable resin composition according to any one of claims 1 to 13, characterized in that the monofunctional radical polymerizable compound (B) comprises at least one compound selected from the group consisting of monofunctional acrylamide compounds, monofunctional acrylate compounds, and N-vinyl compounds.

15. The photocurable resin composition according to claim 14, wherein the monofunctional radical polymerizable compound (B) contains an N-vinyl compound, and the content of the N-vinyl group is 80 mol% or less with respect to the total amount of radical polymerizable functional groups in the photocurable resin composition.

16. The photocurable resin composition according to claim 14 or 15, wherein the monofunctional radical polymerizable compound (B) comprises an N-vinyl compound, and the N-vinyl compound has a cyclic structure.

17. The photocurable resin composition according to claim 16, characterized in that the N-vinyl compound is at least one compound selected from the group consisting of N-vinylpyrrolidone, N-vinyl-ε-caprolactam, N-vinylimidazole, N-vinylmorpholine, and vinylmethyloxazolidinone.

18. The photocurable resin composition according to any one of claims 14 to 17, wherein the monofunctional radical polymerizable compound (B) comprises a monofunctional acrylamide compound, and the monofunctional acrylamide compound has a cyclic structure.

19. The photocurable resin composition according to claim 18, characterized in that the monofunctional acrylamide compound is acryloylmorpholine or phenylacrylamide.

20. The photocurable resin composition according to any one of claims 15 to 19, wherein the monofunctional radical polymerizable compound (B) further comprises a monofunctional methacrylate compound, and the content of the methacrylate group is 25 mol% or less with respect to the total amount of radical polymerizable functional groups in the photocurable resin composition.

21. The photocurable resin composition according to any one of claims 1 to 20, characterized in that the monofunctional radical polymerizable compound (B) does not contain a compound having an alicyclic hydrocarbon group, or if it does, the amount thereof is 50 parts by mass or less with respect to 100 parts by mass of the total of the polyfunctional radical polymerizable compound (A) and the monofunctional radical polymerizable compound (B).

22. The photocurable resin composition according to any one of claims 1 to 21, characterized in that the rubber particles (C) include at least one selected from the group consisting of butadiene rubber, crosslinked butadiene rubber, and styrene / butadiene copolymer rubber.

23. The photocurable resin composition according to any one of claims 1 to 22, characterized in that the rubber particles (C) have a core-shell structure in which at least a portion of the rubber-containing core is covered with a shell made of a polymer of a radically polymerizable compound.

24. The photocurable resin composition according to any one of claims 1 to 23, characterized in that the average particle diameter of the rubber particles (C) is 20 nm or more and 10 μm or less.

25. A cured product obtained by polymerizing a photocurable resin composition according to any one of claims 1 to 24.

26. A method for manufacturing articles using stereolithography, A step of arranging a photocurable resin composition to a predetermined thickness, A step of curing the photocurable resin composition by irradiating it with light energy based on slice data of a three-dimensional model, Includes, A method for producing an article, characterized in that the photocurable resin composition is the photocurable resin composition described in any one of claims 1 to 24.

27. The method for manufacturing an article according to claim 26, characterized in that the light energy is light emitted from a laser light source or a projector.

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