JP7630926B2 - CURABLE RESIN COMPOSITION, ITS CURED PRODUCT, AND METHOD FOR PRODUCING THREE-DIMENSIONAL OBJECT - Google Patents

Description

The present invention relates to a curable resin composition, its cured product, and a method for producing a three-dimensional object.

There is known an optical three-dimensional modeling method (hereinafter referred to as "optical modeling") in which a photocurable resin composition is selectively irradiated with light based on the three-dimensional shape of a three-dimensional model to form a cured resin layer, and then the process is repeated to produce a shaped object in which the cured resin layers are integrally laminated.
Specifically, according to slice data generated from the three-dimensional shape data of the three-dimensional model to be produced, the liquid surface of the liquid photocurable resin composition contained in the container is irradiated with light such as an ultraviolet laser, and a cured resin layer having a desired thickness and a desired pattern is formed. Next, a layer of photocurable resin composition is supplied on the cured resin layer, and light is irradiated in the same manner to form a new cured resin layer continuous with the previously formed cured resin layer. In this way, the cured resin layers are laminated in a pattern based on the slice data, thereby obtaining a desired three-dimensional object. According to such a photo-molding method, if there is three-dimensional shape data of the three-dimensional model, it is possible to easily produce a three-dimensional object having a complex shape.
The application of stereolithography is expanding to the creation of prototypes for shape confirmation (rapid prototyping), the creation of working models for functionality verification, and the creation of molds (rapid tooling).Furthermore, in recent years, the use of stereolithography has begun to spread to the creation of actual products (rapid manufacturing).
In light of this background, there is a demand for curable resin compositions that have high impact resistance comparable to that of general-purpose engineering plastics and high heat resistance such that they do not deform even at relatively high temperatures, and that can be used to form three-dimensional objects.
Patent Document 1 discloses a curable resin composition containing a urethane (meth)acrylate having a specific structure, a radical polymerizable compound, elastomer particles, and a radical polymerization initiator. Patent Document 2 discloses a curable resin composition containing an oxetane compound, a compound having two or more epoxy groups other than an oxetanyl group, a photocationic polymerization initiator, a radical polymerizable compound, and a photoradical polymerization initiator.

JP 2004-51665 A JP 2013-23574 A

However, the curing of the curable resin composition described in Patent Document 1 was insufficient in terms of heat resistance and impact resistance, although good mechanical strength was obtained. In addition, in Patent Document 2, high heat resistance and good toughness (snap fit property) were obtained, but the impact resistance was insufficient, and it was insufficient in terms of achieving both high impact resistance and high heat resistance.
An object of the present invention is to provide a curable resin composition which can give a cured product having excellent heat resistance and impact resistance.

The curable resin composition according to the present invention comprises:
A polyfunctional carbonate (meth)acrylate having at least two (meth)acryloyl groups and at least one carbonate group in the molecule and represented by the following general formula (1):

（式（１）中、ｎは１以上の数を表す。Ｒは炭素数４以上１８以下のアルキレン基であり、前記アルキレン基を構成する炭素原子は、酸素原子、硫黄原子、またはケイ素原子に置き換えられていてもよい。Ｒ同士は同じであっても異なってもよい。Ｘは、水素原子またはメチル基を表す。）
分子内に１個以上のラジカル重合性官能基を有するラジカル重合性化合物と、
平均粒径が０．１０μｍ以上２．０μｍ以下であるゴム粒子と、
ラジカル重合開始剤と、
を含有する硬化性樹脂組成物であって、
前記多官能カーボネート（メタ）アクリレートと前記ラジカル重合性化合物の合計１００質量部に対して、前記多官能カーボネート（メタ）アクリレートの含有量は１質量部以上７０質量部以下であり、前記ラジカル重合性化合物の含有量は３０質量部以上９９質量部以下であり、前記ゴム粒子の含有量は２質量部以上６５質量部以下であり、前記ラジカル重合開始剤の含有量は０．１質量部以上１５質量部以下であり、
前記硬化性樹脂組成物における前記ラジカル重合性化合物の配合比は質量基準で７０／１２７以上であり、
前記ゴム粒子は、コア構造及びシェル構造を有し、
前記ゴム粒子の前記コア構造は、ブタジエンゴム、架橋ブタジエンゴム、及びスチレン／ブタジエン共重合ゴムからなる群から選ばれる少なくとも一種を含有することを特徴とする。

(In formula (1), n represents a number of 1 or more. R represents an alkylene group having 4 to 18 carbon atoms, and a carbon atom constituting the alkylene group may be replaced with an oxygen atom, a sulfur atom , or a silicon atom. R may be the same or different. X represents a hydrogen atom or a methyl group.)
a radical polymerizable compound having one or more radical polymerizable functional groups in the molecule;
Rubber particles having an average particle size of 0.10 μm or more and 2.0 μm or less;
A radical polymerization initiator;
A curable resin composition comprising:
relative to a total of 100 parts by mass of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound, the content of the polyfunctional carbonate (meth)acrylate is 1 part by mass or more and 70 parts by mass or less, the content of the radical polymerizable compound is 30 parts by mass or more and 99 parts by mass or less, the content of the rubber particles is 2 parts by mass or more and 65 parts by mass or less, and the content of the radical polymerization initiator is 0.1 parts by mass or more and 15 parts by mass or less,
a blending ratio of the radical polymerizable compound in the curable resin composition is 70/127 or more by mass,
The rubber particles have a core structure and a shell structure,
The core structure of the rubber particle is characterized in that it contains at least one rubber selected from the group consisting of butadiene rubber, crosslinked butadiene rubber, and styrene/butadiene copolymer rubber.

The present invention provides a curable resin composition that can form a cured product with excellent impact resistance and heat resistance and is suitable for three-dimensional modeling.

The following describes an embodiment of the present invention. Note that the embodiment described below is merely one embodiment of the present invention, and the present invention is not limited to these embodiments.

<Polyfunctional carbonate (meth)acrylate>
The curable resin composition according to the present invention contains a polyfunctional carbonate (meth)acrylate having at least two (meth)acryloyl groups and at least one carbonate group in the molecule and represented by the following general formula (1).

In formula (1), n represents a number of 1 or more. R represents an alkylene group having 4 to 18 carbon atoms, and the carbon atoms constituting the alkylene group may be replaced with oxygen atoms, sulfur atoms, nitrogen atoms, or silicon atoms. Groups containing these atoms include, for example, groups containing ether bonds, ester bonds, urea bonds, thiourea bonds, and thiol bonds. R may be the same or different. X represents a hydrogen atom or a methyl group.
In the general formula (1), n is preferably a number equal to or greater than 2. In other words, the polyfunctional carbonate (meth)acrylate preferably contains two or more carbonate groups in the molecule.

The polyfunctional carbonate (meth)acrylate can be obtained using a carbonate polyol such as polycarbonate polyol. Examples of carbonate polyols include compounds represented by the following general formula (2).

n represents a number of 1 or more. R is an alkylene group having 4 to 18 carbon atoms, and the carbon atoms constituting the alkylene group may be replaced with oxygen atoms, sulfur atoms, nitrogen atoms, or silicon atoms. Groups containing these atoms include, for example, groups containing ether bonds, ester bonds, urea bonds, thiourea bonds, and thiol bonds. The Rs may be the same or different.

Examples of the alkylene group represented by R include linear alkylene groups, alicyclic alkylene groups, unsaturated alkylene groups, and unsaturated alicyclic alkylene groups.

Examples of polyols that can be used as raw materials for carbonate polyols include diols that do not have side chains, such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanodiol, 1,10-dodecanediol, 1,11-undecanediol, and 1,12-dodecanediol, 2-methyl-1,8-octanediol, 2-ethyl-1,6-hexanediol, 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, and 2-butyl-2-ethyl-1,3-propanediol. Examples of the diols include diols having a side chain such as propanediol and 2,2-dimethyl-1,3-propanediol, cyclic diols such as 1,4-cyclohexanedimethanol, 2-bis(4-hydroxycyclohexyl)-propane and isosorbide, and diols having an aromatic ring such as hydroquinone, 1,4-benzenedimethanol, 3,6-bis(hydroxymethyl)durene, bisphenol A, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol F, bisphenol G, bisphenol M, bisphenol S, bisphenol P, bisphenol PH, bisphenol TMC, bisphenol Z, 4,4'-dihydroxybiphenyl, and 4,4'-biphenyldimethanol. One or a combination of two or more of these diols can be used.

Furthermore, compounds having three or more hydroxyl groups per molecule, such as trimethylolethane, trimethylolpropane, hexanetriol, tris(2-hydroxyethyl) isocyanurate, pentaerythritol, and dipentaerythritol, can be used as raw materials for carbonate polyols, provided that the performance of the polyfunctional carbonate (meth)acrylate is not impaired.

Carbonates that are the raw material for carbonate polyols include dialkyl carbonates such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and dibutyl carbonate, diaryl carbonates such as diphenyl carbonate, and alkylene carbonates such as ethylene carbonate, trimethylene carbonate, 1,2-propylene carbonate, 1,2-butylene carbonate, 1,3-butylene carbonate, and 1,2-pentylene carbonate. One or more of these carbonates can be used as raw materials. When dialkyl carbonates and/or diaryl carbonates are used, it is preferable to easily obtain polycarbonate diols having a specific ratio of primary OH groups at the terminals by adjusting conditions such as the feed ratio of diol and carbonate. Furthermore, from the viewpoints of ease of availability and ease of setting polymerization reaction conditions, it is more preferable to use ethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and dibutyl carbonate.

As a polycarbonate diol suitable as a raw material for carbonate polyol, a commercially available product can be used. Examples of commercially available polycarbonate diols include Duranol (trademark) (manufactured by Asahi Kasei Corporation), Benebiol (trademark) (manufactured by Mitsubishi Chemical Corporation), Eternacol (trademark) (manufactured by Ube Industries, Ltd.), Nipporan (manufactured by Tosoh Corporation), and Kuraray Polyol (manufactured by Kuraray Co., Ltd.).

Polyfunctional carbonate (meth)acrylates can be obtained by condensing a carbonate polyol, such as polycarbonate polyol, with (meth)acrylic acid, a (meth)acrylic acid ester, a (meth)acrylic acid halide, or the like. Polyfunctional carbonate (meth)acrylates can also be obtained by reacting a carbonate polyol, such as polycarbonate polyol, with a compound having a group that reacts with the carbonate polyol.

The weight average molecular weight (Mw) of the polyfunctional carbonate (meth)acrylate is preferably 500 to 60,000, more preferably 600 to 50,000, and even more preferably 700 to 50,000. If the weight average molecular weight is 500 or more, the impact resistance of the cured product tends to increase with a decrease in crosslink density, which is preferable. If the weight average molecular weight is 60,000 or less, the viscosity of the curable composition tends to be appropriate and easy to handle. The weight average molecular weight (Mw) of the polyfunctional carbonate (meth)acrylate is a weight average molecular weight calculated based on the molecular weight of standard polystyrene, and is measured by using a high performance liquid chromatography (for example, a high performance GPC apparatus "HLC-8220GPC" manufactured by Tosoh Corporation) with a column (for example, "Shodex GPCLF-804" manufactured by Showa Denko K.K. (exclusion limit molecular weight: 2 × 10 ⁶ , separation range: 300 to 2 × 10 ⁶ ). In this case, two or more columns may be used in series.

The content of the polyfunctional carbonate (meth)acrylate is preferably 1 part by mass or more and 70 parts by mass or less, more preferably 2 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound described below. When the content of the polyfunctional carbonate (meth)acrylate is within this range, it is possible to achieve both high impact resistance and heat resistance. When the content of the polyfunctional carbonate (meth)acrylate is 1 part by mass or more, sufficient impact resistance is obtained. Furthermore, when the content of the polyfunctional carbonate (meth)acrylate is 70 parts by mass or less, sufficient heat resistance is obtained and the viscosity of the resin composition is appropriate.

<Radical Polymerizable Compound>
The curable resin composition according to the present invention includes a radical polymerizable compound having one or more radical polymerizable functional groups in the molecule, which is different from a polyfunctional carbonate (meth)acrylate. The radical polymerizable functional group includes an ethylenically unsaturated group. Specifically, the ethylenically unsaturated group includes a (meth)acryloyl group, a vinyl group, and the like. In this specification, the (meth)acryloyl group means an acryloyl group or a methacryloyl group. In addition, the (meth)acrylate-based compound means a compound having an acrylate group or a compound having a methacrylate group, and the (meth)acrylamide-based compound means a compound having an acrylamide group or a compound having a methacrylamide group.

Examples of monofunctional radically polymerizable compounds having a (meth)acryloyl group include monofunctional (meth)acrylamide compounds and monofunctional (meth)acrylate compounds.

Examples of monofunctional (meth)acrylamide compounds include (meth)acrylamide, N-methyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-t-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)acryloylmorpholine, N-(meth)acryloylpiperidine, and N-[3-(dimethylamino)propyl]acrylamide.

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, 3-hydroxy-1-adamantyl (meth)acrylate, 3,5-dihydroxy-1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate, 2-isopropyl 1-2-adamantyl (meth)acrylate, 2-hydroxyethyl (meth)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, phenyl cellosolve (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, biphenyl (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, glycerol (meth)acrylate, trifluoromethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, octafluoropentyl acrylate, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, allyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate acrylate, 1H,1H,5H,octafluoropentyl (meth)acrylate, epichlorohydrin modified butyl (meth)acrylate, epichlorohydrin modified phenoxy (meth)acrylate, ethylene oxide (EO) modified phthalic acid (meth)acrylate, EO modified succinic acid (meth)acrylate, caprolactone modified 2-hydroxyethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, morpholino (meth)acrylate, EO modified phosphoric acid (meth)acrylate, methyl allyloxyacrylate (product name: AO-MA, manufactured by Nippon Shokubai Co., Ltd.), (meth)acrylates with imide groups (product name: M-140, manufactured by Toagosei Co., Ltd.), monofunctional (meth)acrylates with siloxane structures, etc.

Examples of monofunctional radically polymerizable compounds having an ethylenically unsaturated group other than a (meth)acryloyl group 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-vinylcaprolactam, N-vinylimidazole, N-vinylmorpholine, and N-vinylacetamide.

These monofunctional radically polymerizable compounds may be used alone or in combination of two or more.

Examples of 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, 1,6-hexyl acrylate, 1,7-hexyl acrylate, 1,8-hexyl acrylate, 1,9-hexyl acrylate, 2,3-hexyl acrylate, 2,4-hexyl acrylate, 2,5-hexyl acrylate, 2,6-hexyl acrylate, 2,7-hexyl acrylate, 2,8-hexyl acrylate, 2,5-hexyl acrylate, 2,6-hexyl acrylate, 2,7 ...5-hexyl acrylate, 2,6-hexyl acrylate, 2,7-hexyl acrylate, 2,5-hexyl acrylate, 2,5-hexyl acrylate, 2,5-hexyl acrylate, 2,5-hexyl acrylate, 2,5-hexyl acrylate, 2,5-hexyl acrylate, 2,5-hexyl acrylate, Examples of the di(meth)acrylate include hexamethylene di(meth)acrylate, hydroxypivalic acid ester 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 hydroxypivalic acid neopentyl glycol (e.g., KAYARAD HX-220, HX-620, etc., manufactured by Nippon Kayaku Co., Ltd.), di(meth)acrylate of EO adduct of bisphenol A, polyfunctional (meth)acrylate having a fluorine atom, polyfunctional (meth)acrylate having a siloxane structure, and urethane (meth)acrylate having at least two (meth)acryloyl groups and at least two urethane groups in the molecule.

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.

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

Examples of polyfunctional (meth)acrylamide compounds include N,N'-methylenebisacrylamide, N,N'-ethylenebisacrylamide, N,N'-(1,2-dihydroxyethylene)bisacrylamide, N,N'-methylenebismethacrylamide, N,N',N''-triacryloyldiethylenetriamine, 2,2-bis[(acryloyloxy)methyl]propane-1,3-diyl=diacrylate, 2-[(acryloyloxy)methyl]-2-(hydroxymethyl)propane-1,3-diyl=diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, ditrimethylolpropane tetraacrylate, pentaerythritol tetraacrylate, dipentaerythritol polyacrylate, dipentaerythritol hexaacrylate, trimethylolpropane trimethacrylate, and N-[tris(3-acrylamidopropoxymethyl)methyl]acrylamide.

Examples of polyfunctional maleimide compounds include 4,4'-diphenylmethane bismaleimide, m-phenylene bismaleimide, bisphenol A diphenyl ether bismaleimide, 3,3'-dimethyl-5,5'-diethyl-4,4'-diphenylmethane bismaleimide, 4-methyl-1,3-phenylene bismaleimide, and 1,6-bismaleimide-(2,2,4-trimethyl)hexane.

Examples of 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 hexavinyl ether.

Examples of polyfunctional aromatic vinyl compounds include divinylbenzene.

These polyfunctional radical polymerizable compounds may be used alone or in combination of two or more.

From the viewpoint of increasing the curing speed, it is preferable that the radical polymerizable compound contains at least a (meth)acrylamide-based compound or a (meth)acrylate-based compound. It is more preferable that the radical polymerizable compound contains at least a monofunctional (meth)acrylamide-based compound or a monofunctional (meth)acrylate-based compound. In particular, it is preferable that the radical polymerizable compound contains a (meth)acrylamide-based compound. By containing a (meth)acrylamide-based compound or a (meth)acrylate-based compound in the radical polymerizable compound, the curing speed can be improved. Furthermore, by containing a (meth)acrylamide-based compound or a (meth)acrylate-based compound in the radical polymerizable compound, it is possible to realize a molded object having particularly excellent impact resistance. This is thought to be because the mixed resin composition consisting of a polyfunctional carbonate (meth)acrylate and a radical polymerizable compound penetrates into the rubber particles described later and causes the rubber particles to swell appropriately. As a result, the impact resistance of the cured product is improved significantly.

The content of the radical polymerizable compound is preferably 30 parts by mass or more and 99 parts by mass or less, more preferably 40 parts by mass or more and 98 parts by mass or less, relative to 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound. When the content of the radical polymerizable compound is within this range, it is possible to achieve both high impact resistance and heat resistance. When the content of the radical polymerizable compound is 99 parts by mass or less, sufficient impact resistance is obtained. Furthermore, when the content of the radical polymerizable compound is 30 parts by mass or more, sufficient heat resistance is obtained and the viscosity of the resin composition is appropriate.

<Rubber particles>
The curable resin composition according to the present invention contains rubber particles. By containing the rubber particles in the curable resin composition, the impact resistance of the cured product can be significantly improved.

The type of rubber particles is not particularly limited. Preferred polymers constituting the rubber particles include, for example, butadiene rubber, styrene/butadiene copolymer rubber, acrylonitrile/butadiene copolymer rubber, saturated rubber obtained by hydrogenating or partially hydrogenating these diene rubbers, crosslinked butadiene rubber, isoprene rubber, chloroprene rubber, natural rubber, silicone rubber, ethylene/propylene/diene monomer terpolymer rubber, acrylic rubber, silicone/acrylic composite rubber, and urethane rubber. These polymers may be used alone or in combination of two or more. Among them, from the viewpoint of flexibility, at least one selected from the group consisting of butadiene rubber, crosslinked butadiene rubber, styrene/butadiene copolymer rubber, acrylic rubber, silicone/acrylic composite rubber, and urethane rubber is particularly preferred.

The rubber particles are preferably rubber particles having a core structure and a shell structure that covers the outside of the core structure (hereinafter, sometimes referred to as "core-shell rubber particles"). The polymer constituting the core structure of the rubber particles may be any of the polymers exemplified as preferred polymers constituting the rubber particles described above, but at least one selected from the group consisting of butadiene rubber, crosslinked butadiene rubber, and styrene/butadiene copolymer rubber is more preferred. It is preferable to use styrene/butadiene copolymer rubber as the core structure and change the ratio of styrene to butadiene, since it is possible to control the particle size of the core structure, the glass transition temperature of the copolymer rubber, the breaking stress, the breaking elongation, and other physical properties. Examples of commercially available styrene/butadiene copolymer rubber include latex manufactured by JSR Corporation.

The shell structure includes a polymer of a compound having radical polymerization properties, and examples of the polymers include (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, glycidyl (meth)acrylate, 3-methyl-3-oxetanyl-methyl (meth)acrylate, isobornyl (meth)acrylate, maleimide, styrene, α-allyloxymethyl acrylic acid ester, etc., but are not limited thereto. The shell structure may also include a polymer of a reactive crosslinking monomer having two or more reactive functional groups in the molecule, such as divinylbenzene, allyl (meth)acrylate, ethylene glycol di(meth)acrylate, diallyl maleate, triallyl cyanurate, diallyl phthalate, butylene glycol diacrylate, etc. It is preferable that the polymers constituting the core structure and the shell structure are different polymers. By using rubber particles having such a core structure and shell structure, it is possible to improve the dispersibility of the rubber particles in the mixed resin composition of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound. As a result, a cured product is obtained in which the rubber particles are dispersed, and the rubber particles function effectively in the cured product, significantly improving impact resistance.

The polymer of the compound having radical polymerization properties that forms the shell structure is preferably graft-polymerized onto the surface of the core structure via a chemical bond, and has a form that covers a part or the whole of the core structure. The rubber particles having the core structure and the shell structure, in which the shell structure is graft-polymerized onto the core structure, can be formed by graft-polymerizing a compound having radical polymerization properties by a known method in the presence of particles that will become the core structure. For example, the rubber particles can be produced by adding a compound having radical polymerization properties, which is a component of the shell structure, to latex particles dispersed in water, which can be prepared by emulsion polymerization, mini-emulsion polymerization, suspension polymerization, etc., and polymerizing the particles. In addition, when there are no or very few reactive sites such as ethylenically unsaturated groups that can be graft-polymerized onto the surface of the core structure, an intermediate layer containing reactive sites may be provided on the surface of the particles that will become the core structure, and then the shell structure may be graft-polymerized. In other words, the form of the rubber particles having the core structure and the shell structure also includes a form in which the shell structure is provided on the core structure via an intermediate layer.

As the compound having radical polymerizability for forming the shell structure, the compound described as the radical polymerizable compound can be suitably used. In this case, the compound used as the radical polymerizable compound in the composition and the compound having radical polymerizability used in the shell structure do not need to be the same. As the polymer of the compound having radical polymerizability used in the shell structure, it is preferable to use one or more compounds appropriately selected from the viewpoints of compatibility with the core structure and dispersibility of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound in the composition. In addition to the compound described as the radical polymerizable compound, the compound described as the polyfunctional carbonate (meth)acrylate may be used in combination as the compound having radical polymerizability for forming the shell structure. In this case, the compound used as the polyfunctional carbonate (meth)acrylate in the composition and the compound having radical polymerizability used in the shell structure do not need to be the same.

When a shell structure is formed using a polyfunctional radical polymerizable compound, the viscosity of the curable resin composition tends to be low and easy to handle. The polyfunctional radical polymerizable compound used to form the shell structure is preferably 0 parts by mass or more and 40 parts by mass or less, more preferably 0 parts by mass or more and 30 parts by mass or less, and even more preferably 0 parts by mass or more and 25 parts by mass or less, relative to 100 parts by mass of the compound having radical polymerizability for forming the shell structure. If the content of the polyfunctional radical polymerizable compound is 40 parts by mass or less, it becomes easier to obtain the effect of improving impact resistance by adding rubber particles having a core structure and a shell structure. The polyfunctional radical polymerizable compound used to form the shell structure can be appropriately selected from the viewpoint of compatibility with the core structure and dispersibility in the resin composition, and for example, one or more types of polyfunctional radical polymerizable compounds contained in the radical polymerizable compound may be used in combination.

As the rubber particles, commercially available rubber particles can be used. For example, Metablen (trademark) (manufactured by Mitsubishi Chemical Corporation), Kane Ace (trademark) (manufactured by Kaneka Corporation), etc. can be used.

The mass ratio of the core structure to the shell structure in rubber particles having a core structure and a shell structure is preferably 1 part by mass or more and 200 parts by mass or less, more preferably 2 parts by mass or more and 180 parts by mass or less, per 100 parts by mass of the core structure. If the mass ratio of the core structure to the shell structure is within this range, the impact resistance is greatly improved by including the rubber particles. When the shell structure is 1 part by mass or more, it is sufficiently dispersible in the curable resin composition, and the impact resistance improvement effect is easily obtained. Also, when the shell structure is 200 parts by mass or less, a sufficient impact resistance improvement effect can be obtained without adding a large amount of rubber particles, and the viscosity of the curable resin composition is moderate, making it easy to handle.

The average particle size of the rubber particles is preferably 0.10 μm or more and 2.0 μm or less, more preferably 0.15 μm or more and 1.0 μm or less. When the average particle size is 0.10 μm or more, the increase in viscosity due to addition and the interaction between rubber particles due to the increase in the specific surface area of the rubber particles are unlikely to occur, and the heat resistance and impact resistance of the cured product can be sufficiently obtained. Also, when the average particle size is 2.0 μm or less, the dispersibility of the rubber particles in the curable resin composition is sufficiently obtained, and the effect of improving the impact resistance by adding the rubber particles is sufficiently obtained. For the average particle size of the rubber particles, the arithmetic (number) average particle size is used, and the value measured by the dynamic light scattering method is used. For example, the rubber particles can be dispersed in an appropriate organic solvent and measured using a particle size distribution meter. When the average particle size of the rubber particles is in the range of 0.15 μm or more and 1.0 μm or less, the dispersibility of the rubber particles in the curable resin composition is more stable, and high impact resistance of the cured product is obtained.

The content of the rubber particles is preferably 2 parts by mass or more and 65 parts by mass or less, more preferably 5 parts by mass or more and 60 parts by mass or less, based on 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound. If the content of the rubber particles is within this range, a cured product that has both high impact resistance and heat resistance can be obtained. If the content of the rubber particles is 2 parts by mass or more, the effect of improving impact resistance by adding the rubber particles can be sufficiently obtained. Furthermore, if the content of the rubber particles is 65 parts by mass or less, in addition to the heat resistance of the obtained cured product being sufficient, the viscosity of the curable resin composition is moderate and it is easy to handle.

<Radical Polymerization Initiator>
The curable resin composition according to the present invention contains a radical polymerization initiator. As the radical polymerization initiator, a photoradical polymerization initiator or a thermal radical polymerization initiator can be used.

[Photoradical polymerization initiator]
Photoradical polymerization initiators are mainly classified into intramolecular cleavage type and hydrogen abstraction type. In intramolecular cleavage type photoradical polymerization initiators, the bond at a specific site is cut by absorbing light of a specific wavelength, and radicals are generated at the cut site, which become polymerization initiators and start polymerization of polyfunctional carbonate (meth)acrylate and radical polymerizable compounds. On the other hand, in the case of hydrogen abstraction type, the light of a specific wavelength is absorbed and becomes excited, and the excited species causes hydrogen abstraction reaction from surrounding hydrogen donors, generating radicals, which become polymerization initiators and start polymerization of polyfunctional carbonate (meth)acrylate and radical polymerizable compounds.

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 types in which the bond adjacent to the carbonyl group undergoes α-cleavage to generate radical species. Examples of alkylphenone-based photoradical polymerization initiators include benzyl methyl ketal-based photoradical polymerization initiators, α-hydroxyalkylphenone-based photoradical polymerization initiators, and aminoalkylphenone-based photoradical polymerization initiators. Specific examples of the compounds include benzyl methyl ketal-based photoradical polymerization initiators such as 2,2'-dimethoxy-1,2-diphenylethan-1-one (Irgacure (trademark) 651, manufactured by BASF Corporation), and α-hydroxyalkylphenone-based photoradical polymerization initiators such as 2-hydroxy-2-methyl-1-phenylpropan-1-one (Darocure 1173, manufactured by BASF Corporation), 1-hydroxycyclohexyl phenyl ketone (Irgacure 184, manufactured by BASF Corporation), 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one (Irgacure 185, manufactured by BASF Corporation), and α-hydroxyalkylphenone-based photoradical polymerization initiators such as 1-hydroxycyclohexyl phenyl ketone (Irgacure 186, manufactured by BASF Corporation). Examples of the aminoalkylphenone-based photoradical polymerization initiator include, but are not limited to, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (Irgacure 907, BASF Corporation) and 2-benzylmethyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone (Irgacure 369, BASF Corporation). Examples of acylphosphine oxide-based photoradical polymerization initiators include, but are not limited to, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin 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, but are not limited to, (2E)-2-(benzoyloxyimino)-1-[4-(phenylthio)phenyl]octan-1-one (Irgacure OXE-01, manufactured by BASF). An example of a product name is given in parentheses.

Examples of hydrogen abstraction type radical polymerization initiators include 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, but are not limited to these.

These photoradical polymerization initiators may be used alone or in combination of two or more. They may also be used in combination with a thermal radical polymerization initiator, which will be described later.

The amount of photoradical polymerization initiator added is preferably 0.1 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound. When the amount of photoradical polymerization initiator is 0.1 parts by mass or more, polymerization is sufficient. When the amount of photoradical polymerization initiator is 15 parts by mass or less, the molecular weight is sufficiently increased, and sufficient heat resistance or impact resistance is obtained.

[Thermal radical polymerization initiator]
The thermal radical polymerization initiator is not particularly limited as long as it generates radicals by heating, and conventionally known compounds can be used. For example, preferred examples include azo compounds, peroxides, and persulfates. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(methyl isobutyrate), 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 persulfates such as ammonium persulfate, sodium persulfate, and potassium persulfate.

The amount of thermal radical polymerization initiator added is preferably 0.1 to 15 parts by mass, more preferably 0.1 to 10 parts by mass, per 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radically polymerizable compound. When the amount of thermal radical polymerization initiator is 0.1 parts by mass or more, polymerization is sufficient. When the amount of thermal radical polymerization initiator is 15 parts by mass or less, the molecular weight increases sufficiently, and sufficient heat resistance or impact resistance is obtained.

<Other ingredients (additives)>
The curable resin composition of the present invention may contain various additives as other optional components within a range that does not impair the object and effect of the present invention. The amount of the additives added is preferably 0.05 parts by mass or more and 25 parts by mass or less, more preferably 0.1 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound.

For example, physical property modifiers for imparting desired physical properties to the cured product include resins such as epoxy resins, polyurethanes, polychloroprene, polyesters, polysiloxanes, petroleum resins, xylene resins, ketone resins, and cellulose resins, as well as polycarbonates, modified polyphenylene ethers, polyamides, polyacetals, polyethylene terephthalates, polybutylene terephthalates, ultra-high molecular weight polyethylenes, polyphenylsulfones, polysulfones, polyarylates, polyetherimides, polyetheretherketones, and polyphenylenes. Other examples of the additives that may be added include engineering plastics such as polystyrene sulfide, polyethersulfone, polyamideimide, liquid crystal polymers, polytetrafluoroethylene, polychlorotrifluoroethylene, and polyvinylidene fluoride, fluorine-based oligomers, silicone-based oligomers, and polysulfide-based oligomers, soft metals such as gold, silver, and lead, and layered crystal structure materials such as graphite, molybdenum disulfide, tungsten disulfide, boron nitride, graphite fluoride, calcium fluoride, barium fluoride, lithium fluoride, silicon nitride, and molybdenum selenide.

In addition, photosensitizers such as polymerization inhibitors such as phenothiazine and 2,6-di-t-butyl-4-methylphenol, benzoin compounds, acetophenone compounds, anthraquinone compounds, thioxanthone compounds, ketal compounds, benzophenone compounds, tertiary amine compounds, and xanthone compounds may be added.

Other additives include polymerization initiators, leveling agents, wettability improvers, surfactants, plasticizers, UV absorbers, silane coupling agents, inorganic fillers, pigments, dyes, antioxidants, flame retardants, thickeners, and defoamers.

<Curable resin composition>
The composition of the present invention can be produced by charging appropriate amounts of a polyfunctional carbonate (meth)acrylate, a radically polymerizable compound, rubber particles, and a radical polymerization initiator, as well as other optional components as necessary, into a stirring vessel and stirring the mixture usually at a temperature of 0° C. or higher and 120° C. or lower, preferably 20° C. or higher and 100° C. or lower, and then removing volatile solvents and the like as necessary.

The curable resin composition of the present invention can be suitably used as a modeling material for use in stereolithography. That is, a modeled object of a desired shape can be produced by selectively irradiating the curable resin composition of the present invention with active energy rays such as ultraviolet or visible light, electron beams, X-rays, or radiation to supply the energy required for curing. When the curable resin composition of the present invention is used as a modeling material for stereolithography, the viscosity at 25°C is preferably 10 mPa·s or more and 10,000 mPa·s or less, and more preferably 10 mPa·s or more and 5,000 mPa·s or less.

<Cured Product>
The resin cured product of the present invention can be obtained by curing the above-mentioned curable resin composition using a known method such as active energy ray irradiation or heat irradiation. Examples of active energy rays include ultraviolet and visible light rays, electron beams, X-rays, and radiation. Among them, ultraviolet and visible light rays having a wavelength of 300 nm or more and 450 nm or less can be preferably used in terms of easy availability and compatibility with the photoradical polymerization initiator. As a light source of ultraviolet and visible light rays, ultraviolet and visible light lasers (for example, Ar lasers, He-Cd lasers, etc.), mercury lamps, xenon lamps, halogen lamps, fluorescent lamps, etc. can be used. Among them, laser light sources are preferably used because they can increase the energy level to shorten the modeling time, and have excellent light collecting properties to obtain high modeling accuracy. The curing method can be appropriately selected according to the type of radical polymerization initiator contained in the curable resin composition. In addition, the curing methods may be used alone or in combination.

<Method of manufacturing a three-dimensional object>
The curable resin composition of the present invention can be suitably used as a modeling material for photo-molding. A three-dimensional object obtained by curing the curable resin composition of the present invention can be produced using a known photo-molding method and device. A representative example of a preferred photo-molding method is a method having a step of photo-curing the curable resin composition layer by layer to form a molded object based on slice data generated from three-dimensional shape data of a three-dimensional model. Specifically, a cured layer is formed by selectively irradiating active energy rays based on slice data so that a cured layer having a desired pattern is obtained from the liquid curable resin composition. Next, an uncured layer made of a liquid curable resin composition is supplied in contact with this cured layer, and similarly irradiated with active energy rays based on the slice data to newly form a cured layer continuous with the cured layer. A method of finally obtaining a desired three-dimensional object corresponding to a three-dimensional model by repeating this lamination step can be mentioned.

When irradiating an uncured layer made of a curable resin composition with active energy rays to form each cured resin layer having a desired shape pattern, active energy rays focused in a dot pattern, such as laser light, may be irradiated in a pointillist or line drawing manner. Alternatively, a method may be adopted in which the uncured layer is irradiated with active energy rays in a planar manner through a planar drawing mask formed by arranging multiple microscopic optical shutters, such as liquid crystal shutters or digital micromirror shutters.

The free liquid surface method is a typical example of the photo-lithography method. First, in a container containing a liquid curable resin composition, a support stage that can be freely raised and lowered is lowered (sunk) a predetermined amount from the liquid surface of the resin composition to supply the curable resin composition onto the support stage. Next, the curable resin composition on the support stage is selectively irradiated with light based on slice data to form a cured layer (1) that has been hardened into a solid state. Next, the support stage is lowered a predetermined amount, a curable resin composition is supplied onto the cured layer (1), and the curable resin composition is selectively irradiated with light based on slice data to form a new cured layer (2) on the cured layer (1) so that it is continuously and integrally laminated therewith. In this way, by repeating this process a predetermined number of times, with or without changing the pattern of light irradiation of the curable resin composition for each layer based on slice data, a three-dimensional object is formed in which multiple cured layers (1, 2, ... n) are laminated integrally. In addition, it can also be modeled by a pre-formed liquid surface method or an inkjet method.

The object thus obtained is removed from the container and washed as necessary to remove the unreacted curable resin composition remaining on the surface. As a cleaning agent, an alcohol-based organic solvent such as isopropyl alcohol or ethyl alcohol; a ketone-based organic solvent such as acetone, ethyl acetate, or methyl ethyl ketone; or an aliphatic organic solvent such as terpenes can be used. After removing the unreacted curable resin composition, post-curing with active energy rays or heat may be performed as necessary. By performing post-curing, the unreacted curable resin composition remaining on the surface and inside of the object can be cured, which can suppress stickiness of the surface of the object and improve the initial strength of the object.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

<Ingredients>
The materials used in the examples and comparative examples are listed below.

[Polyfunctional carbonate (meth)acrylate]
A-1: Polycarbonate diacrylate represented by the general formula ( 1 ) (R=( _CH2 ) ₆ or 1,4-dimethylenecyclohexane, X=H, Mw=900) (product name: UM-90(1/3)DA, manufactured by Ube Industries, Ltd.)
A-2: Polycarbonate diacrylate represented by the general formula ( 1 ) (R=(CH ₂ ) ₆ , X=H, Mw=1,000) (product name: UH-100DA, manufactured by Ube Industries, Ltd.)

[Radical polymerizable compound]
B-1: Acryloylmorpholine (product name: ACMO, manufactured by KJ Chemicals Co., Ltd.)
B-2: Bifunctional acrylic monomer (product name: KAYARAD HX-220, manufactured by Nippon Kayaku Co., Ltd.)
B-3: N-phenylmaleimide (product name: imilex (trademark)-P, manufactured by Nippon Shokubai Co., Ltd.)

[Radical Polymerization Initiator]
D-1: Photoradical polymerization initiator (product name: Irgacure 819, manufactured by BASF)

<Rubber particles having a core structure and a shell structure>
[Preparation of acetone dispersion of core-shell rubber particles (C-1) having an average particle size of 0.28 μm]
A 1 L glass container was charged with 185 parts by mass of polybutadiene latex (product name: Nipol LX111A2, manufactured by Zeon Corporation) (corresponding to 100 parts by mass of polybutadiene rubber particles) and 315 parts by mass of deionized water, and the mixture was stirred at 60° C. while being purged with nitrogen. After adding 0.005 parts by mass of disodium ethylenediaminetetraacetate (EDTA), 0.001 parts by mass of ferrous sulfate heptahydrate, and 0.2 parts by mass of sodium formaldehyde sulfoxylate, a mixture of 17.5 parts by mass of methyl methacrylate (MMA) and 17.5 parts by mass of 3-methyl-3-oxetanyl-methyl methacrylate (product name: ETERNACOLL (trademark), OXMA, manufactured by Ube Industries, Ltd.) as a radical polymerizable compound for forming a shell structure, and 0.1 parts by mass of cumene hydroperoxide was continuously added over 2 hours to graft polymerize the radical polymerizable compound onto the surface of the polybutadiene rubber particles. After the addition was completed, the mixture was stirred for another 2 hours to terminate the reaction, and an aqueous dispersion of rubber particles having a core structure and a shell structure, in which polybutadiene rubber was the core structure and a polymer of the radical polymerizable compound was the shell structure, was obtained.

The aqueous dispersion of rubber particles having a core structure and a shell structure obtained as described above was added to 450 parts by mass of acetone and mixed uniformly. After centrifugation for 30 minutes at 12,000 rpm and 10°C, the supernatant was removed. Acetone was added to the settled core and shell structure rubber particles to redisperse them, and the centrifugation and removal of the supernatant were repeated twice under the same conditions as above to obtain an acetone dispersion of core-shell rubber particles (C-1). The average particle size of the core-shell rubber particles (C-1) measured by the method described below was 0.28 μm.

[Preparation of acetone dispersion of core-shell rubber particles (C-2) having an average particle size of 0.066 μm]
An acetone dispersion of core-shell rubber particles (C-2) was obtained in the same manner as in C-1, except that the polybutadiene latex was changed to a styrene-butadiene latex (product name: SBLTX, manufactured by JSR Corporation, grade 2108). The average particle size of the core-shell rubber particles (C-2) was 0.066 μm.

[Preparation of acetone dispersion of core-shell rubber particles (C-3) having an average particle size of 0.81 μm]
An acetone dispersion of core-shell rubber particles (C-3) was obtained in the same manner as in C-1, except that the polybutadiene latex was changed to a styrene-butadiene latex (product name: SBLTX, manufactured by JSR Corporation, grade 0561). The average particle size of the core-shell rubber particles (C-3) was 0.81 μm.

[C-4]
Core-shell rubber particles (product name: Kane Ace (trademark), manufactured by Kaneka Corporation, grade B-564, average particle size 0.17 μm)

<Production of Curable Resin Composition>
A polyfunctional carbonate (meth)acrylate, a radical polymerizable compound, and a radical polymerization initiator were blended and mixed uniformly in the blending ratio shown in Table 1. An acetone dispersion of rubber particles was mixed into this blend, and the volatile acetone was removed using a rotary evaporator to obtain a curable resin composition.

<Creating test pieces>
A cured product was prepared from the prepared curable resin composition by the following method. First, a mold having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was sandwiched between two pieces of quartz glass, and the curable resin composition was poured into the mold. The poured curable resin composition was irradiated with 5 mW/ ^cm2 ultraviolet light from both sides of the mold alternately for 180 seconds each four times using an ultraviolet irradiator (product name: LIGHT SOURCE EXECURE 3000, manufactured by HOYA CANDEO OPTRONICS Co., Ltd.). The obtained cured product was placed in a heating oven at 50 ° C. for 1 hour and in a heating oven at 100 ° C. for 2 hours to perform heat treatment, thereby obtaining a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm.

<Evaluation and measurement methods>
[Weight average molecular weight]
Two columns (product name: Shodex GPC LF-804, product of Showa Denko K.K., exclusion limit molecular weight: 2×10 ⁶ , separation range: 300 to 2×10 ⁶ ) were arranged in series in a gel permeation chromatography (GPC) apparatus (product name: HLC-8220GPC, product of Tosoh Corporation), and measurements were performed at 40° C. using THF as a developing solvent with a refractive index (RI, differential refractive index) detector. The weight average molecular weight obtained is a value calculated in terms of standard polystyrene.

[Average particle size of rubber particles]
Using a particle size distribution meter (product name: Zetasizer Nano ZS, manufactured by Malvern Instruments), about 1 ml of the acetone dispersion of rubber particles was placed in a glass cell and measured at 25° C. The average particle size was determined from the maximum value of the particle size distribution curve (particle size - scattering intensity).

[Deflection temperature under load]
The test pieces were subjected to a bending stress of 1.80 MPa using a deflection temperature under load tester (product name: No. 533 HDT Testing Machine 3M-2, manufactured by Toyo Seiki Seisakusho Co., Ltd.), and the temperature was raised from room temperature at 2°C per minute. The temperature at which the deflection of the test piece reached 0.34 mm was taken as the deflection temperature under load, and was used as an index of heat resistance. The results are shown in Table 1. Heat resistance was evaluated as follows: A (very good) for a deflection temperature under load of 70°C or more, B (good) for a temperature of 60°C or more and less than 70°C, and C (poor) for a temperature of less than 60°C.

[Charpy impact strength]
According to JIS K 7111, a notch of 2 mm depth and 45° was made in the center of the test piece using a notch forming machine (product name: Notching Tool A-4, manufactured by Toyo Seiki Seisakusho Co., Ltd.). Using an impact tester (product name: IMPACT TESTER IT, manufactured by Toyo Seiki Seisakusho Co., Ltd.), the test piece was broken with an energy of 2 J from the back of the notch. The energy required for breaking was calculated from the angle at which the hammer, which had been swung up to 150°, swung up after the test piece was broken, and this was taken as the Charpy impact strength, which was used as an index of impact resistance. The results obtained are shown in Table 1. The impact resistance was evaluated as follows: A (very good) for a Charpy impact strength of 10 kJ/m ² or more, B (good) for 8 kJ/m ² or more and less than 10 kJ/m ² , and C (poor) for less than 8 kJ/m ² .

In the results shown in Table 1, Comparative Example 1 is a system that does not contain a polyfunctional carbonate (meth)acrylate. In Comparative Example 1, the load deflection temperature is 90°C, but the Charpy impact strength is 3.4 kJ/ ^m2 , and it is difficult to say that the heat resistance and toughness are well balanced. On the other hand, Examples 1 to 7 are excellent in toughness and heat resistance, and are given physical properties that exceed the range that can be normally expected. As a result, it has become clear that the curable resin composition of the present invention has an effect of achieving both high toughness and heat resistance, contrary to expectations.

The above results demonstrate that the curable resin composition of the present invention has excellent effects of achieving both impact resistance and heat resistance, and can be suitably used for optical three-dimensional modeling.

Claims (15)

A polyfunctional carbonate (meth)acrylate having at least two (meth)acryloyl groups and at least one carbonate group in the molecule and represented by the following general formula (1):

(In formula (1), n represents a number of 1 or more. R represents an alkylene group having 4 to 18 carbon atoms, and a carbon atom constituting the alkylene group may be replaced with an oxygen atom, a sulfur atom , or a silicon atom. R may be the same or different. X represents a hydrogen atom or a methyl group.)
a radical polymerizable compound having one or more radical polymerizable functional groups in the molecule;
Rubber particles having an average particle size of 0.10 μm or more and 2.0 μm or less;
A radical polymerization initiator;
A curable resin composition comprising:
relative to a total of 100 parts by mass of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound, the content of the polyfunctional carbonate (meth)acrylate is 1 part by mass or more and 70 parts by mass or less, the content of the radical polymerizable compound is 30 parts by mass or more and 99 parts by mass or less, the content of the rubber particles is 2 parts by mass or more and 65 parts by mass or less, and the content of the radical polymerization initiator is 0.1 parts by mass or more and 15 parts by mass or less,
a blending ratio of the radical polymerizable compound in the curable resin composition is 70/127 or more by mass,
The rubber particles have a core structure and a shell structure,
A curable resin composition, wherein the core structure of the rubber particles contains at least one rubber selected from the group consisting of butadiene rubber, crosslinked butadiene rubber, and styrene/butadiene copolymer rubber. the content of the polyfunctional carbonate (meth)acrylate is 30 parts by mass or less per 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound;
and/or
the content of the radical polymerizable compound is 70 parts by mass or more relative to 100 parts by mass in total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound;
The curable resin composition according to claim 1 , The curable resin composition according to claim 1 or 2, characterized in that the radical polymerizable compound contains a monofunctional radical polymerizable compound, and a blending ratio of the monofunctional radical polymerizable compound in the curable resin composition is 60/127 or more on a mass basis. The curable resin composition according to any one of claims 1 to 3, characterized in that the radical polymerizable compound contains a monofunctional radical polymerizable compound, and the content of the monofunctional radical polymerizable compound is 70 parts by mass or more per 100 parts by mass of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound in total. The curable resin composition according to claim 1 , wherein the curable resin composition does not contain a cationic polymerizable compound. The curable resin composition according to any one of claims 1 to 5 , wherein the weight average molecular weight of the polyfunctional carbonate (meth)acrylate is 500 or more and 60,000 or less. 7. The curable resin composition according to claim 1, wherein the radical polymerizable compound contains at least a (meth)acrylamide-based compound or a (meth)acrylate-based compound. The curable resin composition according to any one of claims 1 to 7 , characterized in that the content of the rubber particles is 5 parts by mass or more and 60 parts by mass or less per 100 parts by mass of the total of the polyfunctional carbonate (meth)acrylate and the radical polymerizable compound. 9. The curable resin composition according to claim 1 , wherein the shell structure of the rubber particles contains a polymer of a compound having radical polymerizability. The curable resin composition according to any one of claims 1 to 9 , characterized in that a mass ratio of the core structure to the shell structure of the rubber particles is 1 part by mass or more and 200 parts by mass or less of the shell structure per 100 parts by mass of the core structure. A cured product obtained by curing the curable resin composition according to claim 1 . The Charpy impact strength of the cured product is 8 kJ/m ² The cured product according to claim 11, characterized in that 13. The cured product according to claim 11, wherein the deflection temperature under load of the cured product is 60° C. or higher. A method for manufacturing a three-dimensional object, comprising a step of photo-curing a curable resin composition layer by layer based on slice data to form a model, comprising:
A method for producing a three-dimensional object, comprising the curable resin composition according to claim 1 . The method for producing a three-dimensional object according to claim 14 , further comprising a step of subjecting the object to a post-cure treatment using active energy rays or heat to obtain a three-dimensional object.