Resin composition for photoforming

Abstract

The present invention provides a resin composition for stereolithography, said resin composition being easy to model and having good shaping accuracy, while being suppressed in sedimentation of inorganic particles during storage. This resin composition for stereolithography also has excellent mechanical characteristics as typified by bending strength and bending elastic modulus, while having good color and good color stability. The present invention relates to a resin composition for stereolithography, said resin composition containing (a) a polymerizable monomer, (b) a photopolymerization initiator, (c) inorganic particles having an average particle diameter of from 5 to 500 nm and (d) a hindered phenolic compound, wherein: the content of the photopolymerization initiator (b) is from 0.1 to 10 parts by mass relative to 100 parts by mass of the polymerizable monomer (a); the content of the inorganic particles (c) is from 50 to 400 parts by mass relative to 100 parts by mass of the polymerizable monomer (a); and the content of the hindered phenolic compound (d) is from 0.1 to 500 parts by mass relative to 100 parts by mass of the photopolymerization initiator (b).

Description

[Technical Field]

[0001] The present invention relates to a stereolithography resin composition. More specifically, the present invention relates to a stereolithography resin composition that, when fabricated by a stereolithography method (e.g., a lift-type liquid tank stereolithography method), can produce a three-dimensional object that is easy to fabricate, has good molding precision, inhibits sedimentation of inorganic particles during storage, and is excellent in mechanical properties such as flexural strength and flexural modulus, as well as has good color tone and color tone stability. [Background technology]

[0002] A method for producing a three-dimensional object by repeating the following steps has become widespread: supplying a required amount of controlled light energy to a liquid photocurable resin to harden it into a thin layer, supplying more liquid photocurable resin on top of it, and then irradiating it with light under controlled conditions to harden the resulting thin layer. This is known as optical three-dimensional modeling.

[0003] A typical method for optically producing a three-dimensional object is liquid vat stereolithography, which involves selectively irradiating a liquid photocurable resin composition in a container with a computer-controlled ultraviolet laser to form a desired pattern, curing the composition to a predetermined thickness, and then adding a layer of liquid photocurable resin composition on top of the cured layer. The layer is then irradiated with the ultraviolet laser and cured in the same manner as above to form successive cured layers. This lamination process is repeated to produce a three-dimensional object of the final shape. This method has attracted considerable attention in recent years because it allows for the production of desired three-dimensional objects with high accuracy, even for objects with complex shapes, simply and in a relatively short time. Furthermore, while traditionally a method in which a model was lowered from a container containing a large amount of liquid photocurable resin composition was used, recently, a lifting method has become more common, as it requires only a small amount of liquid photocurable resin composition and reduces waste.

[0004] Furthermore, the applications of three-dimensional objects obtained by stereolithography have expanded from mere concept models to test models, prototypes, and the like, and as a result, there is an increasing demand for excellent molding accuracy for these three-dimensional objects. Furthermore, in addition to these properties, excellent properties tailored to the intended use are also required. In particular, in the field of dental materials, the application of stereolithography is expected for prosthetics such as crowns and bridges, which have complex shapes and vary from patient to patient. However, these prosthetics require extremely high molding accuracy (fitability) and mechanical properties. To improve the mechanical properties of the cured product, inorganic particles are generally added to stereolithography resin compositions. However, adding inorganic particles to a stereolithography resin composition increases the viscosity of the composition, making it difficult to model using the composition, and there are problems such as the inorganic particles settling during storage. To avoid the settling of inorganic particles during storage and due to layer pitch restrictions when using stereolithography, inorganic particles with small particle diameters tend to be used, but this results in a problem of even higher viscosity. In particular, in the case of the suspended-type liquid tank stereolithography method, where the amount of liquid is small, it is difficult to supply the stereolithography resin composition to the modeling surface, making it more susceptible to the effects of viscosity. Furthermore, when the particle size of inorganic particles is reduced, the transparency of the material tends to improve, but there is also the problem that coloring or discoloration caused by ultraviolet laser irradiation becomes more noticeable.

[0005] Against this background, Patent Document 1 proposes a technique for imparting high molding accuracy to a stereolithography resin composition by blending a specific amount of a benzotriazole-based ultraviolet absorber. Furthermore, Patent Document 2, for example, proposes a technique for achieving appropriate fluidity by blending a specific amount of inorganic fine particles having a specific particle size. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 8-224790 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-348214 Summary of the Invention [Problem to be solved by the invention]

[0007] The stereolithography resin composition described in Patent Document 1 does not specifically describe its effectiveness in compositions that require the incorporation of inorganic particles, such as dental materials. Furthermore, although ultraviolet absorbers are prone to develop color when irradiated with light, no mention is made of the color tone. The photocurable liquid composition for stereolithography described in Patent Document 2 does not describe at all the sedimentation of inorganic particles during storage or the mechanical properties and color tone of the cured product.

[0008] Therefore, the present invention aims to provide a resin composition for stereolithography that can be used to obtain three-dimensional objects that are easy to shape, have good molding precision, suppress sedimentation of inorganic particles during storage, and have excellent mechanical properties such as bending strength and bending modulus, as well as good color tone and color tone stability when formed by stereolithography. [Means for solving the problem]

[0009] That is, the present invention includes the following inventions. [1] A composition comprising a polymerizable monomer (a), a photopolymerization initiator (b), inorganic particles (c) having an average particle size of 5 to 500 nm, and a hindered phenol compound (d), the content of the photopolymerization initiator (b) is 0.1 to 10 parts by mass relative to 100 parts by mass of the polymerizable monomer (a); the content of the inorganic particles (c) is 50 to 400 parts by mass relative to 100 parts by mass of the polymerizable monomer (a); a stereolithography resin composition in which the content of the hindered phenol compound (d) is 0.1 to 500 parts by mass relative to 100 parts by mass of the photopolymerization initiator (b); [2] The stereolithography resin composition according to [1], which has a consistency of 30 mm or more at 25°C; [3] The stereolithography resin composition according to either [1] or [2], wherein the inorganic particles (c) are surface-treated; [4] The stereolithography resin composition according to any one of [1] to [3], wherein the inorganic particles (c) contain spherical inorganic particles (cI); [5] The stereolithography resin composition according to [4], wherein the spherical inorganic particles (cI) have a sphericity of 0.70 to 0.99; [6] The stereolithography resin composition according to any one of [1] to [5], wherein the inorganic particles (c) have an average particle size of 7.5 to 300 nm; [7] The stereolithography resin composition according to any one of [1] to [6], wherein the inorganic particles (c) have an average particle size of 10 to 200 nm; [8] The stereolithography resin composition according to any one of [1] to [7], which does not contain any inorganic particles other than the inorganic particles (c); [9] The stereolithography resin composition according to any one of [1] to [8], further containing an organic ultraviolet absorber (e);

[10] The stereolithography resin composition according to any one of [1] to [9], wherein the polymerizable monomer (a) contains a bifunctional polymerizable monomer of an aromatic compound;

[11] The stereolithography resin composition according to

[10] , wherein the aromatic compound-based bifunctional polymerizable monomer is at least one selected from the group consisting of 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane and 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane;

[12] The stereolithography resin composition according to any one of [1] to

[11] , wherein the polymerizable monomer (a) contains a monofunctional monomer;

[13] The stereolithography resin composition according to

[12] , wherein the monofunctional monomer contains a (meth)acrylamide-based polymerizable monomer;

[14] The stereolithography resin composition according to any one of [1] to

[13] , wherein the hindered phenol compound (d) contains a compound represented by the following general formula [I] and / or a compound represented by the following general formula [III]: [ka] (In the formula, R 1 ~R 3each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a hydroxyl group; R 1 ~R 3 The groups (excluding the hydroxyl group) are -O-, -S-, -NH-, -N(R 4 R may contain at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—. 4 represents an alkyl group having 1 to 6 carbon atoms. [ka] (In the formula, R 10 and R 11 each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent; Z 1 represents an alkylene group having 1 to 20 carbon atoms which may have a substituent, and Z 2 represents a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom, or an aryl group; n represents an integer of 2 to 6; R 10 , R 11 and Z 1 The group is -O-, -S-, -NH-, -N(R 12 R may contain at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—. 12 represents an alkyl group having 1 to 6 carbon atoms.

[15] The stereolithography resin composition according to

[14] , wherein the hindered phenol compound (d) contains a compound represented by general formula [III]:

[16] In the compound represented by the general formula [III], Z 1 The alkylene group is -O-, -S-, -NH-, -N(R 12 the stereolithography resin composition according to

[15] , wherein the alkyl group is interrupted by at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—;

[17] The stereolithography resin composition according to any one of [1] to

[16] , wherein the content of the hindered phenol compound (d) is 5.0 to 100 parts by mass per 100 parts by mass of the photopolymerization initiator (b);

[18] A dental material comprising a cured product of the stereolithography resin composition according to any one of [1] to

[17] ;

[19] A dental prosthesis comprising a cured product of the stereolithography resin composition according to any one of [1] to

[17] ;

[20] A method for producing a three-dimensional object by a stereolithography method using the stereolithography resin composition according to any one of [1] to

[17] ;

[21] The method according to

[20] , wherein the stereolithography is a suspended bath stereolithography. [Effects of the Invention]

[0010] The stereolithography resin composition of the present invention can be used to produce three-dimensional objects that are easy to mold, have good molding accuracy, are inhibited from settling of inorganic particles during storage, and have excellent mechanical properties such as flexural strength and flexural modulus, as well as good color tone and color stability. Therefore, the composition can be suitably used for various dental materials, particularly dental prostheses. DETAILED DESCRIPTION OF THE INVENTION

[0011] The stereolithography resin composition of the present invention contains a polymerizable monomer (a), a photopolymerization initiator (b), inorganic particles (c) having an average particle size of 5 to 500 nm, and a hindered phenol compound (d). In the stereolithography resin composition of the present invention, the content of the photopolymerization initiator (b) is 0.1 to 10 parts by mass per 100 parts by mass of the polymerizable monomer (a), the content of the inorganic particles (c) is 50 to 400 parts by mass per 100 parts by mass of the polymerizable monomer (a), and the content of the hindered phenol compound (d) is 0.1 to 500 parts by mass per 100 parts by mass of the photopolymerization initiator (b). The stereolithography resin composition of the present invention has a consistency that allows for modeling, resulting in excellent molding accuracy and ease of modeling. The method for measuring the consistency is as described in the Examples below. In this specification, "consistency" is an index showing the ease of spreading of a stereolithography resin composition measured by the method described in the Examples below. A higher consistency value indicates a higher fluidity of the stereolithography resin composition and superior modeling properties, while a lower consistency value indicates a lower fluidity of the stereolithography resin composition. In this specification, the upper and lower limits of the numerical ranges (contents of each component, values ​​calculated from each component, and each physical property, etc.) can be combined as appropriate. In this specification, "stereolithography" is also referred to as "optical three-dimensional modeling."

[0012] Polymerizable monomer (a) A radically polymerizable monomer is preferably used as the polymerizable monomer (a) used in the stereolithography resin composition of the present invention. Specific examples of the radically polymerizable monomer in the polymerizable monomer (a) include (meth)acrylate-based polymerizable monomers; (meth)acrylamide-based polymerizable monomers; esters of α-cyanoacrylic acid, (meth)acrylic acid, α-halogenated acrylic acid, crotonic acid, cinnamic acid, sorbic acid, maleic acid, itaconic acid, and the like; vinyl esters; vinyl ethers; mono-N-vinyl derivatives; styrene derivatives, and the like. Among these, (meth)acrylate-based polymerizable monomers and (meth)acrylamide-based polymerizable monomers are preferred from the viewpoint of curability. These may be used alone or in combination of two or more. In the present invention, the term "(meth)acrylic" is used to encompass both "methacrylic" and "acrylic." The same applies to similar terms such as "(meth)acrylate" and "(meth)acryloyloxy."

[0013] The polymerizable monomer (a) in the present invention includes a monofunctional monomer having one polymerizable group (hereinafter also simply referred to as a "monofunctional monomer") and a polyfunctional monomer having multiple polymerizable groups (hereinafter also simply referred to as a "polyfunctional monomer"). Examples of the monofunctional monomer include a monofunctional (meth)acrylate polymerizable monomer and a monofunctional (meth)acrylamide polymerizable monomer.

[0014] Examples of monofunctional (meth)acrylate polymerizable monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, propylene glycol mono(meth)acrylate, glycerol mono(meth)acrylate, erythritol mono(meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n- Examples of the acrylate include butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, lauryl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, 2,3-dibromopropyl (meth)acrylate, 3-(meth)acryloyloxypropyltrimethoxysilane, and 11-(meth)acryloyloxyundecyltrimethoxysilane. Examples of monofunctional (meth)acrylamide polymerizable monomers include N-(meth)acryloylmorpholine, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-di-n-propyl(meth)acrylamide, N,N-di-n-butyl(meth)acrylamide, N,N-di-n-hexyl(meth)acrylamide, N,N-di-n-octyl(meth)acrylamide, N,N-di-2-ethylhexyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N,N-bis(2-hydroxyethyl)acrylamide. These may be used alone or in combination of two or more. Among these, (meth)acrylamide-based polymerizable monomers are preferred because they have excellent curability and improve molding accuracy when combined with a polyfunctional monomer, and among these, N-(meth)acryloylmorpholine, N,N-dimethyl(meth)acrylamide, and N,N-diethyl(meth)acrylamide are more preferred.

[0015] Examples of polyfunctional monomers include aromatic compound-based bifunctional polymerizable monomers, aliphatic compound-based bifunctional polymerizable monomers, and trifunctional or higher functional polymerizable monomers.

[0016] Examples of aromatic compound-based bifunctional polymerizable monomers include 2,2-bis((meth)acryloyloxyphenyl)propane, 2,2-bis[4-(3-acryloyloxy)-2-hydroxypropoxyphenyl]propane, 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane (commonly known as "Bis-GMA"), 2,2-bis(4-(meth)acryloyloxyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxydiethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxytetraethoxyphenyl)propane, and 2,2-bis(4-(meth)acryloyloxypentaethoxyphenyl)propane. acryloyloxydipropoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxyethoxyphenyl)propane, 2-(4-(meth)acryloyloxydiethoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2-(4-(meth)acryloyloxydipropoxyphenyl)-2-(4-(meth)acryloyloxytriethoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxypropoxyphenyl)propane, 2,2-bis(4-(meth)acryloyloxyisopropoxyphenyl)propane, 1,4-bis(2-(meth)acryloyloxyethyl)pyromellitate, and the like. These may be used alone or in combination of two or more. Among these, 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane and 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane are preferred because of their excellent curability and the mechanical strength of the cured product. Of the 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propanes, 2,2-bis(4-methacryloyloxypolyethoxyphenyl)propane (a compound having an average number of moles of ethoxy groups added of 2.6 (commonly known as "D-2.6E")) is more preferred.

[0017] Examples of the aliphatic compound-based bifunctional polymerizable monomer include glycerol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, Examples of suitable methacrylates include 1,6-hexanediol di(meth)acrylate, 2-ethyl-1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, 1,2-bis(3-methacryloyloxy-2-hydroxypropoxy)ethane, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (commonly known as "UDMA"), and N-methacryloyloxyethyl acrylamide. Among these, 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate is preferred due to its excellent curability and mechanical strength of the cured product. These may be used alone or in combination of two or more.

[0018] Examples of the tri- or higher functional polymerizable monomer include trimethylolpropane tri(meth)acrylate, trimethylolethane tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetra(meth)acrylate, 1,7-diacryloyloxy-2,2,6,6-tetra(meth)acryloyloxymethyl-4-oxaheptane, and N,N',N'',N''',-tetra(meth)acryloyltriethyltetramine. Among these, N,N-(2,2,4-trimethylhexamethylene)bis[2-(aminocarboxy)propane-1,3-diol]tetramethacrylate and 1,7-diacryloyloxy-2,2,6,6-tetraacryloyloxymethyl-4-oxaheptane are preferred because of their excellent curability and the mechanical strength of the cured product. These may be used alone or in combination of two or more.

[0019] When the polymerizable monomer (a) contains a monofunctional (meth)acrylate polymerizable monomer, the content of the monofunctional (meth)acrylate polymerizable monomer in 100% by mass of the total amount of the polymerizable monomer (a) is preferably 10 to 55% by mass, more preferably 15 to 50% by mass, and even more preferably 15 to 45% by mass. When the polymerizable monomer (a) contains a bifunctional (meth)acrylate polymerizable monomer, the content of the bifunctional (meth)acrylate polymerizable monomer in 100% by mass of the total amount of the polymerizable monomer (a) is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more, from the viewpoint of excellent curability and mechanical strength of the cured product. In this specification, the content of a certain polymerizable monomer in 100% by mass of the total amount of polymerizable monomers (a) means the content (mass) of the polymerizable monomer when the total amount of the contained polymerizable monomers (a) is converted to 100% by mass.

[0020] The content of the polymerizable monomer (a) in the entire stereolithography resin composition is preferably 15 to 70 mass %, more preferably 20 to 65 mass %, and even more preferably 25 to 60 mass %.

[0021] Photopolymerization initiator (b) The photopolymerization initiator (b) used in the present invention can be selected from photopolymerization initiators used in general industrial fields, and among them, photopolymerization initiators used in dental applications are preferably used.

[0022] Examples of the photopolymerization initiator (b) include (bis)acylphosphine oxides and their salts, thioxanthones and their quaternary ammonium salts, ketals, α-diketones, coumarins, anthraquinones, benzoin alkyl ether compounds, α-aminoketone compounds, etc. These may be used alone or in combination of two or more.

[0023] Among these photopolymerization initiators (b), it is preferable to use at least one selected from the group consisting of (bis)acylphosphine oxides and their salts, and α-diketones. This provides a stereolithography resin composition that has excellent photocurability in the ultraviolet and visible light regions and exhibits sufficient photocurability when using any light source, such as a laser (e.g., Ar laser, He—Cd laser), or lighting (e.g., halogen lamp, xenon lamp, metal halide lamp, light-emitting diode (LED), mercury lamp, or fluorescent lamp).

[0024] Among the (bis)acylphosphine oxides and salts thereof used as the photopolymerization initiator (b), examples of the acylphosphine oxides and salts thereof include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,3,5,6-tetramethylbenzoyldiphenylphosphine oxide, benzoyldi(2,6-dimethylphenyl)phosphonate, 2,4,6-trimethylbenzoylphenylphosphine oxide sodium salt, 2,4,6-trimethylbenzoyldiphenylphosphine oxide potassium salt, and ammonium salt of 2,4,6-trimethylbenzoyldiphenylphosphine oxide. Examples of bisacylphosphine oxides and salts thereof include bis(2,6-dichlorobenzoyl)phenylphosphine oxide, bis(2,6-dichlorobenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-4-propylphenylphosphine oxide, bis(2,6-dichlorobenzoyl)-1-naphthylphosphine oxide, bis(2,6-dimethoxybenzoyl)phenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,5-dimethylphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide, and salts thereof (alkali metal salts, alkaline earth metal salts, ammonium salts, etc.). Further examples include compounds described in JP-A No. 2000-159621.

[0025] Among these (bis)acylphosphine oxides, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylmethoxyphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, and 2,4,6-trimethylbenzoylphenylphosphine oxide sodium salt are particularly preferred.

[0026] Examples of α-diketones used as the photopolymerization initiator (b) include diacetyl, benzyl, camphorquinone, 2,3-pentadione, 2,3-octadione, 9,10-phenanthrenequinone, 4,4'-oxybenzyl, and acenaphthenequinone. Among these, camphorquinone is particularly preferred when a light source in the visible light range is used.

[0027] From the viewpoint of the curability of the resulting stereolithography resin composition, the content of the photopolymerization initiator (b) in the stereolithography resin composition of the present invention is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 7.5 parts by mass, and even more preferably 1.0 to 5.0 parts by mass, relative to 100 parts by mass of the polymerizable monomer (a). If the content of the photopolymerization initiator (b) exceeds 10 parts by mass relative to 100 parts by mass of the polymerizable monomer (a), precipitation of the photopolymerization initiator from the stereolithography resin composition may occur if the solubility of the photopolymerization initiator itself is low.

[0028] Inorganic particles (c) Examples of inorganic particles (c) used in the present invention include quartz, silica, titanium oxide, zirconium oxide (zirconia), zinc oxide, cerium oxide, aluminum oxide (alumina), silica-titania, silica-titania-barium oxide, silica-zirconia, silica-alumina, barium glass, aluminosilicate glass, fluoroaluminosilicate glass, calcium fluoroaluminosilicate glass, strontium fluoroaluminosilicate glass, barium fluoroaluminosilicate glass, and strontium calcium fluoroaluminosilicate glass. These may also be used alone or in combination of two or more. Among these, quartz, silica, alumina, zirconia, barium glass, and fluoroaluminosilicate glass are preferred, more preferably silica and barium glass, and even more preferably barium glass, because they provide excellent mechanical strength to the cured product of the stereolithography resin composition obtained.

[0029] From the viewpoint of molding precision and suppression of sedimentation, the average particle diameter of the inorganic particles (c) must be 5 to 500 nm, preferably 7.5 to 300 nm, more preferably 10 to 200 nm, and even more preferably 12.5 to 100 nm. If the average particle diameter of the inorganic particles (c) is less than 5 nm, the viscosity of the stereolithography resin composition tends to increase and molding precision tends to decrease. On the other hand, if the average particle diameter of the inorganic particles (c) exceeds 500 nm, irradiated light tends to be easily scattered, tending to decrease molding precision, and the inorganic particles (c) are more likely to settle during storage or molding.

[0030] The shape of the inorganic particles (c) is not particularly limited, but it is preferable to contain spherical inorganic particles (cI) because they have excellent fluidity, which makes it easier to restore the liquid level near the shaped object and results in excellent molding precision. The sphericity of the spherical inorganic particles (cI) is preferably 0.70 to 0.99, more preferably 0.80 to 0.99, and even more preferably 0.90 to 0.99.

[0031] The shape of the inorganic particles (c) can be measured from images taken with a scanning electron microscope (hereinafter referred to as SEM). The average particle size and sphericity can be determined by processing SEM photographs with an image analyzer. The number of samples to be image-processed should be 200 or more, and the average value is used. The "sphericity" defined here substitutes for the circularity determined by image processing of SEM images. The circularity is expressed by the following formula: A circularity of 1 represents a perfect circle. Circularity=(4·π·S) / (L 2 ) (In the formula, S represents the area of ​​the particle obtained by image processing, and L represents the perimeter of the particle.) The particle diameter used to calculate the circularity is the equivalent circle diameter (diameter when assumed to be a perfect circle) = (4·S / π) 1 / 2 It was decided.

[0032] When the inorganic particles (c) are not spherical, the particle diameter can be determined by photographing and processing the image in the same manner as described above. The particle diameter of the particles is determined as the arithmetic mean value of the longest and shortest lengths of the particles, and the average primary particle diameter is calculated from the number of particles and their particle diameters.

[0033] The content of inorganic particles (c) in the stereolithography resin composition of the present invention must be 50 to 400 parts by mass, preferably 75 to 300 parts by mass, and more preferably 100 to 200 parts by mass, per 100 parts by mass of polymerizable monomer (a), from the viewpoints of the consistency of the resulting stereolithography resin composition, the molding precision of the cured product, and the mechanical properties. If the content of inorganic particles (c) is less than 50 parts by mass per 100 parts by mass of polymerizable monomer (a), sufficient mechanical properties cannot be obtained in the three-dimensional object. On the other hand, if the content of inorganic particles (c) is more than 400 parts by mass per 100 parts by mass of polymerizable monomer (a), the fluidity of the stereolithography resin composition decreases, making modeling difficult.

[0034] In order to adjust the miscibility with the polymerizable monomer (a), the inorganic particles (c) are preferably surface-treated in advance with a known surface treatment agent, such as an organic compound containing an acidic group; a fatty acid amide such as saturated fatty acid amide, unsaturated fatty acid amide, saturated fatty acid bisamide, or unsaturated fatty acid bisamide; or an organosilicon compound such as a silane coupling agent. In order to enhance the chemical bonding between the polymerizable monomer (a) and the inorganic particles (c) and thereby improve the mechanical strength of the cured product, the inorganic particles (c) are preferably surface-treated with an organic compound containing an acidic group. Examples of the acidic group-containing organic compound include organic compounds having at least one acidic group, such as a phosphate group, pyrophosphate group, thiophosphate group, phosphonate group, sulfonate group, or carboxylic acid group, with organic compounds having at least one phosphate group being preferred. When two or more surface treatment agents are used, the surface treatment agent layer may be a mixture of two or more surface treatment agents, or a multi-layer structure in which multiple surface treatment agent layers are laminated.

[0035] Examples of acidic group-containing organic compounds containing a phosphoric acid group include 2-ethylhexyl acid phosphate, stearyl acid phosphate, 2-(meth)acryloyloxyethyl dihydrogen phosphate, 3-(meth)acryloyloxypropyl dihydrogen phosphate, 4-(meth)acryloyloxybutyl dihydrogen phosphate, 5-(meth)acryloyloxypentyl dihydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate, 7- (Meth)acryloyloxyheptyl dihydrogen phosphate, 8-(meth)acryloyloxyoctyl dihydrogen phosphate, 9-(meth)acryloyloxynonyl dihydrogen phosphate, 10-(meth)acryloyloxydecyl dihydrogen phosphate, 11-(meth)acryloyloxyundecyl dihydrogen phosphate, 12-(meth)acryloyloxydodecyl dihydrogen phosphate, 16-(meth)acryloyloxyhexadecyl dihydrogen hydrogen phosphate, 20-(meth)acryloyloxyicosyl dihydrogen phosphate, bis[2-(meth)acryloyloxyethyl]hydrogen phosphate, bis[4-(meth)acryloyloxybutyl]hydrogen phosphate, bis[6-(meth)acryloyloxyhexyl]hydrogen phosphate, bis[8-(meth)acryloyloxyoctyl]hydrogen phosphate, bis[9-(meth)acryloyloxynonyl]hydrogen phosphate, bis[ [10-(meth)acryloyloxydecyl]hydrogenphosphate, 1,3-di(meth)acryloyloxypropyl dihydrogenphosphate, 2-(meth)acryloyloxyethylphenylhydrogenphosphate, 2-(meth)acryloyloxyethyl-2-bromoethylhydrogenphosphate, bis[2-(meth)acryloyloxy-(1-hydroxymethyl)ethyl]hydrogenphosphate, and acid chlorides, alkali metal salts, and ammonium salts thereof.

[0036] Furthermore, as the acidic group-containing organic compound having an acidic group such as a pyrophosphate group, a thiophosphate group, a phosphonate group, a sulfonic acid group, or a carboxylic acid group, for example, those described in WO 2012 / 042911 can be suitably used.

[0037] Examples of saturated fatty acid amides include palmitic acid amide, stearic acid amide, and behenic acid amide. Examples of unsaturated fatty acid amides include oleic acid amide and erucic acid amide. Examples of saturated fatty acid bisamides include ethylene bispalmitic acid amide, ethylene bisstearic acid amide, and hexamethylene bisstearic acid amide. Examples of unsaturated fatty acid bisamides include ethylene bisoleic acid amide, hexamethylene bisoleic acid amide, and N,N'-dioleylsebacic acid amide.

[0038] As the organic silicon compound, R 13 m SiW 4-m In the formula, R 13 is a substituted or unsubstituted hydrocarbon group having 1 to 12 carbon atoms, W is an alkoxy group having 1 to 4 carbon atoms, a hydroxy group, a halogen atom or a hydrogen atom, and m is an integer of 0 to 3, provided that R 13 When there are a plurality of Ws, they may be the same or different.

[0039] Specific examples include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, isobutyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(β-methoxyethoxy)silane, 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, β-(3,4-epoxycyclohexyl)silane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltriethoxysilane, N-β(aminoethyl)-γ-aminopropyltrimethoxysilane , γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, trimethylsilanol, methyltrichlorosilane, methyldichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, phenyltrichlorosilane, diphenyldichlorosilane, vinyltrichlorosilane, trimethylbromosilane, diethylsilane, vinyltriacetoxysilane, ω-(meth)acryloyloxyalkyltrimethoxysilane [between a (meth)acryloyloxy group and a silicon atom] carbon number: 3 to 12, e.g., γ-methacryloyloxypropyltrimethoxysilane, etc.), ω-(meth)acryloyloxyalkyltriethoxysilane [carbon number between the (meth)acryloyloxy group and the silicon atom: 3 to 12, e.g., γ-methacryloyloxypropyltriethoxysilane, etc.], hexaethyldisilazane, hexa-n-propyldisilazane, hexaisopropyldisilazane, 1,1,2,2-tetramethyl-3,3-diethyldisilazane, 1,1,3,3-tetramethyldisilazane, 1,1,1,3,3,3-hexamethyldisilazane, 1,1,Examples include 1,3,3-pentamethyldisilazane.

[0040] Among these, silane coupling agents having a functional group copolymerizable with a polymerizable monomer, such as ω-(meth)acryloyloxyalkyltrimethoxysilane [number of carbon atoms between the (meth)acryloyloxy group and the silicon atom: 3 to 12], ω-(meth)acryloyloxyalkyltriethoxysilane [number of carbon atoms between the (meth)acryloyloxy group and the silicon atom: 3 to 12], vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, and γ-glycidoxypropyltrimethoxysilane are preferred.

[0041] The surface treatment method can be any known method without any particular limitation, and examples thereof include a method in which the surface treatment agent is sprayed onto the inorganic particles (c) while vigorously stirring the particles, and a method in which the inorganic particles (c) and the surface treatment agent are dispersed or dissolved in a suitable solvent, and then the solvent is removed.

[0042] The amount of the surface treatment agent used is not particularly limited, and is preferably 0.1 to 50 parts by mass, for example, relative to 100 parts by mass of the inorganic particles (c).

[0043] The stereolithography resin composition of the present invention may contain substantially only spherical inorganic particles (cI) as the inorganic particles (c). The content of the spherical inorganic particles (cI) in 100% by mass of the inorganic particles (c) is preferably 60 to 100% by mass, more preferably 80 to 100% by mass, and even more preferably 90 to 100% by mass.

[0044] Hindered phenol compounds (d) The stereolithography resin composition of the present invention contains a hindered phenol compound (d). The hindered phenol compound (d) is used in the stereolithography resin composition of the present invention to suppress coloration of a cured product of the stereolithography resin composition and discoloration after storage.

[0045] Generally, phenolic compounds are blended as polymerization inhibitors or antioxidants to ensure the storage stability of resin compositions. In contrast, in the present invention, hindered phenolic compounds are used to suppress coloration and discoloration (particularly yellowing) caused by irradiation with active energy rays, such as ultraviolet lasers, emitted by stereolithography devices. Among phenolic compounds, hindered phenolic compounds are essential because they have minimal curing inhibition and are excellent in suppressing coloration and discoloration of the cured product. Furthermore, only when the hindered phenolic compound (d) is blended in a specific ratio relative to the photopolymerization initiator (b), can the stereolithography resin composition of the present invention be easily molded, and coloration and discoloration (particularly yellowing) of the cured product be suppressed.

[0046] Examples of the hindered phenol compound (d) include a compound represented by the following general formula [I], a compound represented by the following general formula [II], and a compound represented by the following general formula [III], and the like, and the compound represented by the following general formula [I] and the compound represented by the following general formula [III] are preferred. [ka] (In the formula, R 1 ~R 3 each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a hydroxyl group; R 1 ~R 3 The groups (excluding the hydroxyl group) are -O-, -S-, -NH-, -N(R 4 R may contain at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—. 4 represents an alkyl group having 1 to 6 carbon atoms. [ka] (In the formula, R 5 ~R 8each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a hydroxyl group; X represents an alkylene group having 1 to 20 carbon atoms which may have a substituent; Y represents a vinyloxy group or a (meth)acryloyloxy group; R 5 ~R 8 and the groups of X (excluding hydroxyl groups) are -O-, -S-, -NH-, -N(R 9 R may contain at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—. 9 represents an alkyl group having 1 to 6 carbon atoms. [ka] (In the formula, R 10 and R 11 each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent; Z 1 represents an alkylene group having 1 to 20 carbon atoms which may have a substituent, and Z 2 represents a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom, or an aryl group; n represents an integer of 2 to 6; R 10 , R 11 and Z 1 The group is -O-, -S-, -NH-, -N(R 12 R may contain at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—. 12 represents an alkyl group having 1 to 6 carbon atoms.

[0047] R 1 ~R 3 and R 5 ~R 8The alkyl group having 1 to 20 carbon atoms may be linear or branched. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a 2-methylpropyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a 1-ethylpropyl group, a 1,1-dimethylpropyl group, an n-hexyl group, a 1-methylpentyl group, a 1-ethylbutyl group, a 2-ethylbutyl group, a 1,1-dimethylbutyl group, an n-heptyl group, a 2-methylhexyl group, an n-octyl group, an isooctyl group, a tert-octyl group, an n-nonyl group, an n-decyl group, a 1-methylnonyl group, an n-undecyl group, and an n-dodecyl group. 1 ~R 3 and R 5 ~R 8 The alkyl group in R may be unsubstituted. 1 ~R 3 and R 5 ~R 8 The number of carbon atoms in the alkyl group R is preferably 1 to 10, and more preferably 1 to 6, in view of the excellent effect of inhibiting coloring and discoloration. 1 ~R 3 and R 5 ~R 8 The alkoxy group having 1 to 20 carbon atoms may be linear or branched. Examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, an n-pentyloxy group, an isopentyloxy group, and an n-hexyloxy group. 1 ~R 3 and R 5 ~R 8 The alkoxy group in R may be unsubstituted. 1 ~R 7 The number of carbon atoms in the alkoxy group of R is preferably 1 to 10, and more preferably 1 to 6 from the viewpoint of excellent effect of inhibiting coloring and discoloration. 1 ~R 3 and R 5 ~R 8Examples of the aryl group having 6 to 12 carbon atoms include a phenyl group, a benzyl group, and a naphthyl group. The number of carbon atoms in the aryl group is preferably 6 to 10. 1 ~R 3 and R 5 ~R 8 Examples of the substituents on the alkyl group, alkoxy group, and aryl group in R include a linear or branched alkyl group having 1 to 10 carbon atoms, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom), and a carboxy group. 4 and R 9 The alkyl group of R 1 ~R 3 and R 5 ~R 8 Among the alkylene groups mentioned above, those having 1 to 6 carbon atoms in the alkyl group are preferred. The alkylene group having 1 to 20 carbon atoms for X may be linear or branched, and examples thereof include methylene, methylmethylene, ethylene, n-propylene, isopropylene, n-butylene, 1-methylbutylene, n-pentylene, 1,1-dimethylpropylene, n-hexylene, n-heptylene, n-octylene, n-nonylene, and n-decylene. The alkylene group for X preferably has 1 to 10 carbon atoms, more preferably 1 to 6, and even more preferably 1 to 4, from the viewpoint of excellent suppression of coloring and discoloration. Y is preferably a (meth)acryloyloxy group, more preferably an acryloyloxy group. In a preferred embodiment, the hindered phenol compound (d) contains a compound represented by general formula [I], and R 1 ~R 3 The group is -O-, -S-, -NH-, -N(R 4 Examples of the stereolithography resin composition include a stereolithography resin composition that does not contain a bonding group of —O(CO)—, —O(CO)—, or —CO—.

[0048] R 10 and R 11 The alkyl group, alkoxy group and aryl group of R 1 ~R 3 and R 5 ~R 8 Similar examples include R 10 and R11 As R, an alkyl group is preferable, and from the viewpoint of excellent effect of inhibiting coloration and discoloration, a branched alkyl group is more preferable, and a branched alkyl group having 3 to 6 carbon atoms is even more preferable. 12 The alkyl group of R 4 and R 9 The same can be mentioned as Z. 1 The alkylene group of Z may be the same as that of X. 2 represents a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom, or an aryl group, and is preferably a carbon atom, a sulfur atom, or an aryl group. 2 The aryl group in R 1 ~R 3 and R 5 ~R 8 The same groups as those listed above are included, and a phenyl group is preferred, a substituted phenyl group is more preferred, and a substituted phenyl group substituted with an alkyl group having 1 to 3 carbon atoms is even more preferred. n represents an integer of 2 to 6, and an integer of 2 to 4 is preferred. n represents Z 2 In another preferred embodiment, the hindered phenol compound (d) includes a compound represented by the general formula [III], and Z 1 The alkylene group is -O-, -S-, -NH-, -N(R 12 )-, -O(CO)-, and -CO-. 1 The alkylene group of the formula (I) is preferably a hindered phenol compound containing at least one bonding group selected from the group consisting of -O-, -O(CO)-, and -CO-, and Z 1 is an alkylene group having 1 to 6 carbon atoms, and the alkylene group contains at least one bonding group selected from the group consisting of -O-, -O(CO)-, and -CO-, and a hindered phenol compound is more preferred, 2is a carbon atom, and a hindered phenol compound in which n is 4 is more preferred. In this specification, when a group (e.g., an alkylene group) is interrupted by a specific bonding group, it means that the bonding group is contained in the middle of the group (e.g., an alkylene group), and both terms have the same meaning. For example, Z 1 When the alkylene group is an ethylene group and contains -O-, Z 1 means -CH2-O-CH2-.

[0049] Examples of the hindered phenol compound (d) include 3,5-di-t-butyl-4-hydroxytoluene, 3,5-di-t-butyl-4-hydroxyanisole, 2,6-di-t-butyl-4-hydroxytoluene, 2,6-di-t-butyl-4-hydroxyanisole, 4-t-butylpyrocatechol, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], thiodiethylene Examples of suitable hydroxytoluene include ethylene bis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, N,N'-hexane-1,6-diylbis(3-(3,5-di-t-butyl-4-hydroxyphenylpropionamide)), octyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate (IRGANOX 1135), 3,3',3",5,5',5"-hexa-t-butyl-α,α',α"-(mesitylene-2,4,6-triyl)tri-p-cresol, and 4,6-bis(octylthiomethyl)-o-cresol. Among these, 3,5-di-t-butyl-4-hydroxytoluene is preferably used because of its small curing inhibitory effect and strong discoloration suppression effect.

[0050] The content of the hindered phenol compound (d) in the stereolithography resin composition must be 0.1 to 500 parts by mass relative to 100 parts by mass of the photopolymerization initiator (b), preferably 0.5 to 300 parts by mass, more preferably 1.0 to 200 parts by mass, even more preferably 5.0 to 100 parts by mass, and most preferably 10 to 50 parts by mass. By setting the content of the hindered phenol compound (d) to 0.1 to 500 parts by mass, curability, color tone, and color tone stability are maintained favorably. If the content of the hindered phenol compound (d) is less than 0.1 part by mass relative to 100 parts by mass of the photopolymerization initiator (b), molded articles of the stereolithography resin composition tend to yellow and have poor color tone and color tone stability. On the other hand, if the content of the hindered phenol compound (d) is more than 500 parts by mass relative to 100 parts by mass of the photopolymerization initiator (b), the degree of polymerization when the stereolithography resin composition is molded decreases, resulting in a tendency for the mechanical strength of the molded articles to decrease. In particular, when using liquid layer stereolithography, modeling becomes difficult due to factors such as falling off and modeling interruptions caused by insufficient hardening.

[0051] Organic UV absorber (e) The stereolithography resin composition of the present invention preferably contains an organic ultraviolet absorber (e) in order to further improve molding precision.

[0052] Examples of the organic ultraviolet absorber (e) include benzotriazole-based compounds, benzophenone-based compounds, and thiophene-based compounds. Benzotriazole-based compounds are preferably compounds in which a hydroxy group is bonded to the 2-position of an aromatic ring bonded to a nitrogen atom of a triazole structure. From the viewpoint of further improving molding precision, more preferred are compounds in which a hydroxy group is bonded to the 2-position of an aromatic ring bonded to a nitrogen atom of a triazole structure and an alkyl group having 1 to 10 carbon atoms is bonded to the 3- and / or 5-position of the aromatic ring. Benzotriazole-based compounds include 2-(2-hydroxy-5-methylphenyl)benzotriazole ("TINUVIN P"), 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole ("TINUVIN P"). 329"), 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-amylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, and the like. Examples of benzophenone compounds include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-(dodecyloxy)benzophenone, 2-hydroxy-4-(octadecyloxy)benzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, and 2,2'-dihydroxy-4,4'-dimethoxybenzophenone. Examples of thiophene compounds include thiophene compounds such as 2,5-bis(5-t-butyl-2-benzoxazolyl)thiophene. Among these, benzotriazole compounds are preferred from the viewpoint of improving molding accuracy.

[0053] The organic ultraviolet absorber (e) may be used alone or in combination of two or more. The content of the organic ultraviolet absorber (e) is preferably in the range of 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, and even more preferably 0.02 to 2 parts by mass, relative to 100 parts by mass of the polymerizable monomer (a).

[0054] The stereolithography resin composition of the present invention is not particularly limited as long as it contains the polymerizable monomer (a), photopolymerization initiator (b), inorganic particles (c), and hindered phenol compound (d), and may contain an organic UV absorber (e) as needed, or may contain other components other than these. The content of other components in the stereolithography resin composition (i.e., components other than the polymerizable monomer (a), polymerization initiator (b), inorganic particles (c), and hindered phenol compound (d), and optionally the organic UV absorber (e)) may be less than 3% by mass, less than 2% by mass, less than 1% by mass, or even 0% by mass, based on the total amount of the stereolithography resin composition. A preferred embodiment of the present invention is a stereolithography resin composition containing a polymerizable monomer (a), a photopolymerization initiator (b), inorganic particles (c), and a hindered phenol compound (d), and optionally an organic UV absorber (e), wherein the inorganic particles (c) have an average particle size of 7.5 to 300 nm, and the composition does not contain any inorganic particles (f) other than the inorganic particles (c). The inorganic particles (f) are not particularly limited, and examples thereof include metal oxide particles (f-1) having an average particle size of 0.5 μm or more. The average particle size of the inorganic particles (f) may vary depending on the average particle size of the inorganic particles (c), and may be 0.4 μm or more, or 0.3 μm or more. The metal oxide particles (f-1) are not particularly limited, and examples thereof include at least one selected from the group consisting of titanium oxide, aluminum oxide, zirconium oxide, zinc oxide, and cerium oxide. The stereolithography resin composition of the present invention can be produced according to known methods.

[0055] The stereolithography resin composition of the present invention may contain a polymerization accelerator to improve photocurability, provided that the invention is not impaired by the accelerator. Examples of the accelerator include amine compounds such as ethyl 4-(N,N-dimethylamino)benzoate, methyl 4-(N,N-dimethylamino)benzoate, n-butoxyethyl 4-(N,N-dimethylamino)benzoate, 2-(methacryloyloxy)ethyl 4-N,N-dimethylaminobenzoate, 4-(N,N-dimethylamino)benzophenone, and butyl 4-(N,N-dimethylamino)benzoate. Among these, at least one selected from the group consisting of ethyl 4-(N,N-dimethylamino)benzoate, n-butoxyethyl 4-(N,N-dimethylamino)benzoate, and 4-(N,N-dimethylamino)benzophenone is preferred for imparting excellent curability to the stereolithography resin composition.

[0056] The stereolithography resin composition of the present invention may contain a known stabilizer to prevent deterioration of physical properties or to adjust photocurability. Examples of such stabilizers include polymerization inhibitors and antioxidants (with the exception of the hindered phenol compound (d)). In one embodiment, the stereolithography resin composition does not contain any polymerization inhibitor or antioxidant other than the hindered phenol compound (d).

[0057] The stereolithography resin composition of the present invention may contain known additives for adjusting the color tone or paste properties, such as pigments, dyes, organic solvents, and thickeners.

[0058] The stereolithography resin composition of the present invention is easy to mold, has good molding precision, inhibits sedimentation of inorganic particles during storage, and has excellent mechanical properties such as flexural strength and flexural modulus, as well as good color tone and color stability. Therefore, the stereolithography resin composition of the present invention can be used in applications where these advantages are utilized, such as for various three-dimensional objects produced by curing using a stereolithography method. The cured product (three-dimensional object) of the stereolithography resin composition of the present invention can be particularly suitably used as a dental material, and is particularly suitable for dental prostheses.

[0059] Another embodiment of the present invention includes a method for producing a three-dimensional object (e.g., a dental material, particularly preferably a dental prosthesis) by a conventionally known optical three-dimensional modeling method (e.g., a suspended liquid tank stereolithography method) using any of the above-mentioned stereolithography resin compositions.

[0060] When a conventionally known stereolithography method (e.g., a suspended liquid tank stereolithography method) is performed using the stereolithography resin composition of the present invention, any conventionally known stereolithography method and apparatus (e.g., a stereolithography machine such as the DIGITALWAX (registered trademark) 028J-Plus manufactured by DWS) can be used. Among these, in the present invention, it is preferable to use active energy rays as the light energy for curing the resin. In the present invention, "active energy rays" refers to energy rays capable of curing the stereolithography resin composition, such as ultraviolet rays, electron beams, X-rays, radiation, and high frequency waves. For example, the active energy rays may be ultraviolet rays having a wavelength of 300 to 400 nm. Examples of light sources for active energy rays include lasers such as Ar lasers and He-Cd lasers; and lighting such as halogen lamps, xenon lamps, metal halide lamps, LEDs, mercury lamps, and fluorescent lamps. Lasers are particularly preferred. When a laser is used as the light source, it is possible to increase the energy level and shorten the modeling time, and by taking advantage of the excellent focusing properties of the laser beam, it is possible to obtain three-dimensional objects with high molding precision.

[0061] As described above, when performing stereolithography using the stereolithography resin composition of the present invention, any of the conventionally known methods (e.g., suspended liquid tank stereolithography) and conventionally known stereolithography systems can be used without any particular limitation. However, a representative example of a stereolithography method preferably used in the present invention is a method that involves selectively irradiating a stereolithography resin composition with an active energy ray to form a cured layer having a desired pattern, followed by repeatedly supplying an uncured liquid stereolithography resin composition to the cured layer and similarly irradiating it with an active energy ray to form a new cured layer continuous with the cured layer, thereby laminating the cured layer, thereby finally obtaining the desired three-dimensional object. The three-dimensional object thus obtained can be used as is, or, in some cases, can be post-cured by light irradiation or heat to further improve its mechanical properties or shape stability before use.

[0062] The present invention includes embodiments in which the above-described configurations are combined in various ways within the scope of the technical concept of the present invention, as long as the effects of the present invention are achieved. [Example]

[0063] Next, the present invention will be explained in more detail by way of examples, but the present invention is not limited to these examples, and many modifications within the scope of the technical concept of the present invention are possible by those skilled in the art. Each component used in the stereolithography resin composition according to the examples or comparative examples is explained below together with its abbreviation.

[0064] [Polymerizable monomer (a)] UDMA: 2,2,4-trimethylhexamethylenebis(2-carbamoyloxyethyl)dimethacrylate (Kyoeisha Chemical Co., Ltd.) Bis-GMA: 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane (manufactured by Shin-Nakamura Chemical Co., Ltd.) TEGDMA: Triethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) ACMO: N-acryloylmorpholine (KJ Chemicals Co., Ltd.)

[0065] [Photopolymerization initiator (b)] TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide

[0066] [Inorganic particles (c)] Inorganic particles (c)-1: γ-methacryloyloxypropyltrimethoxysilane-treated spherical silica particles "Admanano (registered trademark)" YA050C (manufactured by Admatechs Co., Ltd., average particle diameter: 50 nm, sphericity: 0.97) Inorganic particles (c)-2: γ-methacryloyloxypropyltrimethoxysilane-treated spherical silica particles "Admanano (registered trademark)" YC100C (manufactured by Admatechs Co., Ltd., average particle diameter: 100 nm, sphericity: 0.98) Inorganic particles (c)-3: γ-methacryloyloxypropyltrimethoxysilane-treated spherical silica particles "Admafine (registered trademark) SO-C1" (manufactured by Admatechs Co., Ltd., average particle diameter: 300 nm, sphericity: 0.96)

[0067] [Inorganic particles other than inorganic particles (c)] Inorganic particles (large particle size): γ-methacryloyloxypropyltrimethoxysilane-treated spherical silica particles "Admafine (registered trademark)" SO-C4 (manufactured by Admatechs Co., Ltd., average particle size: 1.0 μm)

[0068] [Hindered phenol compounds (d)] BHT: 3,5-di-t-butyl-4-hydroxytoluene PETBHPP: Pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate]

[0069] [Organic UV absorber (e)] HOB: 2-(2-hydroxy-5-tert-octylphenyl)benzotriazole

[0070] [Stabilizers other than hindered phenol compounds (d)] MEHQ: p-Methoxyphenol

[0071] (Examples 1 to 9 and Comparative Examples 1 to 6) The components shown in Tables 1 and 2 were mixed at room temperature (20°C ± 15°C, JIS (Japanese Industrial Standards) Z 8703:1983) to prepare inks as stereolithography resin compositions according to Examples 1 to 9 and Comparative Examples 1 to 6.

[0072] <Formability> 1. Possibility of modeling Using the inks of each example and comparative example, a stereolithography machine (DIGITALWAX (registered trademark) 020D manufactured by DWS) was used to produce a cubic three-dimensional object with a side length of 10,000 mm. The object was visually inspected to determine whether it could be modeled without falling off the base of the stereolithography machine, interruption of modeling, or destruction of the container (damage to the coating material of the tray filled with the resin composition). 2. Consistency A 0.05 mm thick PET film with a square base measuring 50 mm on a flat surface was placed, and 0.5 ml of the ink from each Example and Comparative Example was dropped onto the center of the film and allowed to stand for 10 minutes in a thermostatic chamber at 25°C. The maximum diameter (longer diameter) and minimum diameter (minor diameter) of the ink that spread into a circular shape were then averaged to calculate the ink diameter. Three samples of each Example and Comparative Example ink were measured using this method, and the ink diameter was calculated. The average of these three measurements was taken as the measured consistency. A higher measured consistency indicates easier ink flow and better shaping properties. A consistency of 30 mm or more in this test indicates high fluidity and excellent shaping properties, while a consistency of 40 mm or more is preferred.

[0073] <Forming precision> Using the inks of each example and comparative example, a stereolithography machine (DIGITALWAX (registered trademark) 020D manufactured by DWS) was used to produce a cubic three-dimensional object with a side length of 10,000 mm. The resulting three-dimensional object was washed with ethanol to remove any unpolymerized polymerizable monomer, and then the dimensions (unit: mm) were measured using a micrometer. The molding error for molding precision was calculated using the following formula (n=5). The average calculated values ​​are shown in Tables 1 and 2. A molding error of 1.0% or less indicates excellent molding precision, and when a crown or bridge is molded, it is likely to have excellent compatibility; a molding error of 0.80% or less is preferable. TIFF0007735248000006.tif12170

[0074] <Flexural strength, flexural modulus> Using the compositions listed in Tables 1 and 2 for each Example and Comparative Example, rectangular parallelepiped objects measuring 25.0 mm long, 2.0 mm wide, and 2.0 mm thick were fabricated using a stereolithography machine (DIGITALWAX® 028J-Plus, manufactured by DWS Corporation). The resulting objects were washed with methanol to remove unpolymerized polymerizable monomers, and then further polymerized for 90 seconds using a dental laboratory LED polymerization device ("α Light V," manufactured by Morita Tokyo Manufacturing Co., Ltd.) to obtain cured products. The resulting cured products were polished with 300-grit silicon carbide paper and stored in water at 37°C for 24 hours. The flexural strength (three-point flexural strength) and flexural modulus were measured (n=5) using a precision universal testing machine ("Autograph AG-I 100kN," manufactured by Shimadzu Corporation) at a support distance of 20 mm and a crosshead speed of 1 mm / min. The average values ​​of the measurements are shown in Tables 1 and 2. A cured product having a flexural strength of 100 MPa or more and a flexural modulus of elasticity of 5.0 GPa or more has excellent mechanical strength.

[0075] <Sedimentation> A 2 ml polypropylene centrifuge tube vial was filled with 1 ml of the stereolithography resin composition (ink), and centrifuged at 5,000 rpm for 5 minutes using a centrifuge (MCX-150, manufactured by Tomy Seiko Co., Ltd.). The presence or absence of composition separation was visually confirmed (n=1). If no separation was observed, it was marked with ○, and if separation was observed, it was marked with ×.

[0076] <Color and color stability> For each ink of each Example and Comparative Example, a disk-shaped object measuring 15.0 mm in diameter and 1.0 mm in thickness was produced using the same stereolithography machine as described above. The resulting object was washed with ethanol to remove any unpolymerized polymerizable monomer, and then subjected to secondary polymerization for 5 minutes using a dental laboratory LED polymerization device (manufactured by Morita Tokyo Manufacturing Co., Ltd., product name: "α Light V") to obtain a cured product. The resulting cured product was polished with 1000-grit silicon carbide paper, then with dental lapping film (manufactured by 3M Co.), and then measured for yellowness b using a spectrophotometer (manufactured by Konica Minolta, Inc., SPECTROPHOTOMETER CM-3610A, conforming to JIS Z 8722:2009, condition c, D65 light source). * value, and yellowing degree Δb * The values ​​were measured and the average value was obtained (n=5). The average values ​​are shown in Tables 1 and 2. The yellowing index Δb * The value is defined by the following formula: Δb * =b * (7d) -b * (0d) (In the formula, b * (7d) is the yellowness b in the L*a*b* color system of JIS Z 8781-4:2013 measured 7 days after molding and secondary polymerization. * represents the average value of the * (0d) is the yellowness index b in the L*a*b* color system measured immediately after modeling and secondary polymerization. * represents the average value of the values.) The yellowness b * When the value is 10.0 or less, the dental prosthesis is easily recognized as colorless by visual inspection when it is produced, and it is preferably 8.0 or less. * If the value is 5.0 or less, it is easily recognized by visual inspection that there is no yellowing when a dental prosthesis is produced, and a value of 4.5 or less is preferable.

[0077] [Table 1]

[0078] [Table 2]

[0079] As shown in Tables 1 and 2, the stereolithography resin compositions of Examples 1 to 9 had a consistency sufficient for molding, excellent molding accuracy, and no settling of inorganic particles during storage. Furthermore, the cured products thereof had excellent flexural strength and flexural modulus, and little discoloration. The composition of Comparative Example 1, which contained a small amount of inorganic particles (c), had low flexural strength and flexural modulus. The composition of Comparative Example 2, which contained a large amount of inorganic particles (c), had a measured consistency that was too low and was unsuitable for molding. The composition of Comparative Example 3, which contained inorganic particles with a large particle size, experienced settling of the inorganic particles and poor molding accuracy. The composition of Comparative Example 4, in which the ratio of the content of hindered phenol compound (d) to the content of photopolymerization initiator (b) was too low, exhibited significant discoloration and discoloration. The composition of Comparative Example 5, in which the ratio of the content of hindered phenol compound (d) to the content of photopolymerization initiator (b) was too high, was unsuitable for molding. The composition of Comparative Example 6, which did not contain a hindered phenol compound but contained another stabilizer instead, exhibited significant discoloration and discoloration. [Industrial Applicability]

[0080] The stereolithography resin composition of the present invention is easy to mold, has good molding precision, and inhibits sedimentation of inorganic particles during storage. It also has excellent mechanical properties such as flexural strength and flexural modulus, and has good color tone and color tone stability, making it suitable for various dental materials, particularly dental prostheses.

Claims

1. The composition contains a polymerizable monomer (a), a photopolymerization initiator (b), inorganic particles (c) having an average particle size of 5 to 500 nm, and a hindered phenol compound (d), the content of the photopolymerization initiator (b) is 0.1 to 10 parts by mass relative to 100 parts by mass of the polymerizable monomer (a); the content of the inorganic particles (c) is 50 to 400 parts by mass relative to 100 parts by mass of the polymerizable monomer (a); The content of the hindered phenol compound (d) is 5.0 to 500 parts by mass relative to 100 parts by mass of the photopolymerization initiator (b) (excluding those containing ultraviolet absorbing inorganic particles, and the content of the hindered phenol compound (d) is 5.0 to 500 parts by mass relative to 100 parts by mass of the photopolymerization initiator (b)) (In general formula (1), X is an n-valent hydrocarbon group having 2 to 100 carbon atoms, n is an integer selected from the range of 2 to 4, and R 1 is hydrogen or a methyl group.) (Excluding those containing a polymerizable monomer represented by the formula:)

2. 2. The stereolithography resin composition according to claim 1, which has a consistency of 30 mm or more at 25°C.

3. The stereolithography resin composition according to claim 1 or 2, wherein the inorganic particles (c) are surface-treated.

4. 4. The stereolithography resin composition according to claim 1, wherein the inorganic particles (c) contain spherical inorganic particles (c-I).

5. 5. The stereolithography resin composition according to claim 4, wherein the spherical inorganic particles (cI) have a sphericity of 0.70 to 0.

99.

6. 6. The stereolithography resin composition according to claim 1, wherein the inorganic particles (c) have an average particle size of 7.5 to 300 nm.

7. 7. The stereolithography resin composition according to claim 1, wherein the inorganic particles (c) have an average particle size of 10 to 200 nm.

8. The stereolithography resin composition according to any one of claims 1 to 7, which does not contain any inorganic particles other than the inorganic particles (c).

9. The stereolithography resin composition according to any one of claims 1 to 8, further comprising an organic ultraviolet absorber (e).

10. 10. The stereolithography resin composition according to claim 1, wherein the polymerizable monomer (a) contains a bifunctional polymerizable monomer of an aromatic compound.

11. The stereolithography resin composition according to claim 10, wherein the aromatic compound-based bifunctional polymerizable monomer is at least one selected from the group consisting of 2,2-bis[4-(3-methacryloyloxy-2-hydroxypropoxy)phenyl]propane and 2,2-bis(4-(meth)acryloyloxypolyethoxyphenyl)propane.

12. 12. The stereolithography resin composition according to claim 1, wherein the polymerizable monomer (a) contains a monofunctional monomer.

13. The stereolithography resin composition according to claim 12, wherein the monofunctional monomer contains a (meth)acrylamide-based polymerizable monomer.

14. The stereolithography resin composition according to any one of claims 1 to 13, wherein the hindered phenol compound (d) contains a compound represented by the following general formula [I] and / or a compound represented by the following general formula [III]: 【Chemical 1】 (In the formula, R 1 ~R 3 each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 12 carbon atoms which may have a substituent, or a hydroxyl group; R 1 ~R 3 The groups (excluding hydroxyl groups) are —O—, —S—, —NH—, —N(R 4 )-, —O(CO)-, and —CO-. 4 has 1 to 6 carbon atoms represents an alkyl group represented by the formula: 【Chemistry 2】 (In the formula, R 10 and R 11 each independently represents an alkyl group having 1 to 20 carbon atoms which may have a substituent, an alkoxy group having 1 to 20 carbon atoms which may have a substituent, or an aryl group having 6 to 12 carbon atoms which may have a substituent; Z 1 may have a substituent represents an alkylene group having 1 to 20 carbon atoms; Z 2 represents a carbon atom, an oxygen atom, a nitrogen atom, a sulfur atom, or an aryl group; n represents an integer of 2 to 6; R 10 , R 11 and Z 1 The group is —O—, —S—, —NH—, —N(R 12 )-, —O(CO)-, and —CO-. 12 represents an alkyl group having 1 to 6 carbon atoms.

15. The stereolithography resin composition according to claim 14, wherein the hindered phenol compound (d) contains a compound represented by general formula [III].

16. In the compound represented by the general formula [III], Z 1 The alkylene group is —O—, —S—, —NH—, —N(R 12 16. The stereolithography resin composition according to claim 15, wherein the alkyl group is interrupted by at least one bonding group selected from the group consisting of —O(CO)—, —O(CO)—, and —CO—.

17. The content of the hindered phenol compound (d) is 5.0 to 100 parts by mass per 100 parts by mass of the photopolymerization initiator (b).

18. A dental material comprising a cured product of the stereolithography resin composition according to any one of claims 1 to 17.

19. A dental prosthesis comprising a cured product of the stereolithography resin composition according to any one of claims 1 to 17.

20. A method for producing a three-dimensional object by a stereolithography method using the stereolithography resin composition according to any one of claims 1 to 17.

21. 21. The method of claim 20, wherein the stereolithography process is suspended bath stereolithography.

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