Photopolymerizable composition for three-dimensional printer containing polymerizable monomer having allophanate bond

Abstract

To provide a photopolymerizable composition that has excellent moldability in a three-dimensional printer and can obtain a three-dimensional molded object with excellent toughness by using an optical three-dimensional molding method (photomolding method).SOLUTION: A dental photopolymerizable composition for a three-dimensional printer includes (a) a (meth)acrylic polymerizable compound having an allophanate group, (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups, and (c) a photoinitiator.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a photopolymerizable composition, and more particularly to a photopolymerizable composition which is excellent in formability when used with a 3D printer and which can give a three-dimensional object having excellent toughness. [Background technology]

[0002] A method for producing a three-dimensional object by repeatedly supplying a required amount of controlled light energy to a liquid photocurable resin and hardening it into a thin film is known as optical three-dimensional modeling (photolithography). Numerous proposals have been made since the basic practical methods were proposed.

[0003] Representative methods for optically manufacturing stereolithography include the following. A photopolymerizable composition placed in a container is selectively irradiated with computer-controlled light to obtain the desired pattern, and cured to a specified thickness. Next, one layer of photopolymerizable composition is supplied onto or below the cured layer, and similarly irradiated with light to cure. This process is repeated to form a laminate, and a three-dimensional object having the final shape is generally manufactured.

[0004] This method has been used in a variety of industries in recent years because it can easily produce a desired three-dimensional object in a relatively short time, even if the object has a complex shape.

[0005] In particular, in the field of dental materials, the application of stereolithography is advancing because the shapes of prosthetic devices such as inlays, crowns, and bridges vary from case to case and are complex.

[0006] In the past, stereolithography was used mainly to create prototypes, but with technological advances, its accuracy has improved, and in recent years, its applications have expanded beyond prototyping to the creation of final products. For this reason, there is a demand for models with not only high modeling accuracy but also excellent strength characteristics.

[0007] Representative prosthetic devices produced by such stereolithography include dental mouthpieces and denture base materials. There are several types of dental mouthpieces, such as orthodontic aligners that are worn on the teeth to correct the alignment of the teeth, dental splints that are used to correct the jaw position, those used in contact sports to reduce trauma to the teeth and jawbone during competition, and those worn while sleeping to treat sleep apnea syndrome or to suppress tooth wear due to teeth grinding. Among these, the use of dental mouthpieces has been rapidly increasing in recent years in the fields of orthodontic aligners and sleep apnea syndrome treatment.

[0008] Denture base materials are materials used for the gum area of ​​dentures. In recent years, the demand for dentures has increased due to the declining birthrate and aging population.

[0009] These dental aligner materials and denture base materials require shape recovery and toughness. If the shape recovery is impaired, the material will lose its orthodontic force or shock absorption, and will no longer perform its intended function. Furthermore, if the toughness is impaired, the material will be prone to breakage, and will need to be remade frequently.

[0010] There is a limit to the viscosity of materials that can be modeled using optical 3D modeling (photolithography). Generally, materials with lower viscosity have better modeling properties, but many materials that exhibit shape recovery and toughness have high molecular weights and high viscosities, which reduces modeling properties. Therefore, it has been difficult to obtain a resin composition used in optical 3D modeling that has excellent modeling properties and a cured product with excellent shape recovery and toughness.

[0011] In this background, for example, Patent Document 1 proposes a resin composition for optical three-dimensional modeling, which contains a monofunctional (meth)acrylate monomer and a urethane acrylate, as a technique for obtaining a desired cured product with excellent modeling accuracy. However, in Patent Document 1, the material viscosity is high because urethane acrylate is used, and the material is heated to reduce the viscosity before optical three-dimensional modeling, leaving room for improvement as a material with excellent modeling properties. Patent Documents 2 and 3 propose a composition with low viscosity by blending a monofunctional monomer having an aromatic ring as a technique for reducing the viscosity of a photocurable resin composition without impairing the curability. However, Patent Documents 2 and 3 assume a hard material, leaving room for improvement in terms of flexibility. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Special Publication No. 2021-523247 [Patent Document 2] International Publication No. 2010 / 113600 [Patent Document 3] JP 2017-128688 A Summary of the Invention [Problem to be solved by the invention]

[0013] An object of the present invention is to provide a photopolymerizable composition that has excellent modeling properties when used with a 3D printer and can be used to obtain a three-dimensional object having excellent toughness by using an optical three-dimensional modeling method (stereolithography). [Means for solving the problem]

[0014] That is, the present invention provides: (a) a (meth)acrylic polymerizable compound having an allophanate group; (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups; (c) a photopolymerization initiator; and A dental photopolymerizable composition for 3D printers comprising: Effect of the Invention

[0015] When the photopolymerizable composition of the present invention is modeled by a three-dimensional optical modeling method (stereolithography), a three-dimensional object having excellent modeling properties and excellent toughness can be obtained. Therefore, the three-dimensional object of the present invention can be suitably used as a dental material (e.g., dental aligner, denture base, mouthpiece). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention will be described in detail below. The dental photopolymerizable composition for 3D printers of the present invention is (a) a (meth)acrylic polymerizable compound having an allophanate group; (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups; (c) a photopolymerization initiator.

[0017] The dental photopolymerizable composition for 3D printers of the present invention contains (a) 30 to 99 weight % of a (meth)acrylic polymerizable compound having an allophanate group, and (b) 1 to 70 weight % of a (meth)acrylic polymer having one or two (meth)acryloyloxy groups, and may contain 0.01 to 5 weight parts of (c) a photopolymerization initiator per 100 weight parts in total of (a) the (meth)acrylic polymerizable compound having an allophanate group and (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups.

[0018] In the dental photopolymerizable composition for 3D printers of the present invention, (a) the (meth)acrylic polymerizable compound having an allophanate group can have a viscosity of 60,000 mPa s or less as measured using a rotational rheometer under conditions of a temperature of 23°C and a rotation speed of 20 rpm.

[0019] In the dental photopolymerizable composition for 3D printers of the present invention, the (a) allophanate group-containing (meth)acrylic polymerizable compound can have a glass transition point of 120° C. or lower when cured.

[0020] In the dental photopolymerizable composition for 3D printers of the present invention, (a) the (meth)acrylic polymerizable compound having an allophanate group can have three or more (meth)acryloyloxy groups.

[0021] In the dental photopolymerizable composition for 3D printers of the present invention, (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups may not contain a urethane structure.

[0022] In the dental photopolymerizable composition for 3D printers of the present invention, (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups may include at least one (meth)acrylic polymer having two (meth)acryloyloxy groups.

[0023] The dental photopolymerizable composition for 3D printers of the present invention may contain 1 to 25 parts by weight of a (meth)acrylic polymer having one (meth)acryloyloxy group per 100 parts by weight in total of (a) a (meth)acrylic polymerizable compound having an allophanate group and (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups.

[0024] In the dental photopolymerizable composition for 3D printers of the present invention, (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups may include a (meth)acrylic polymer containing one or more reactive groups selected from the group consisting of hydroxyl groups and carboxylic acid groups.

[0025] In the dental photopolymerizable composition for 3D printers of the present invention, the (c) photopolymerization initiator can be one or more selected from the group consisting of alkylphenone-based compounds, acetophenone-based compounds, and acylphosphine oxide-based compounds.

[0026] The dental photopolymerizable composition for 3D printers of the present invention can have a viscosity of 10,000 mPa·s or less, measured using a rotational rheometer under conditions of a temperature of 23° C. and a rotation speed of 20 rpm.

[0027] The dental photopolymerizable composition for 3D printers of the present invention can have a glass transition point of 30 to 100°C after curing.

[0028] The dental photopolymerizable composition for 3D printers of the present invention may further contain additives.

[0029] The dental photopolymerizable composition for 3D printers of the present invention may include one or more additives selected from the group consisting of colorants, ultraviolet absorbers, polymerization inhibitors, and fluorescent agents.

[0030] The dental photopolymerizable composition for 3D printers of the present invention may contain 0.0001 to 2 parts by weight of an additive relative to 100 parts by weight of the dental photopolymerizable composition for 3D printers excluding the additive.

[0031] The present invention provides a dental product produced by a stereolithography type 3D printer using the dental photopolymerizable composition for 3D printers of the present invention.

[0032] The present invention provides a dental aligner material produced by a stereolithography type 3D printer using the dental photopolymerizable composition for 3D printers of the present invention.

[0033] The present invention provides a denture base material produced by a stereolithography type 3D printer using the dental photopolymerizable composition for 3D printers of the present invention.

[0034] The present invention provides a dental mouthpiece produced by a stereolithography type 3D printer using the dental photopolymerizable composition for 3D printers of the present invention.

[0035] (a) A (meth)acrylic polymerizable compound having an allophanate group has a feature of forming intramolecular hydrogen bonds by having an allophanate group in the molecule. As a result, the intermolecular interaction derived from the urethane bond can be suppressed, and the viscosity can be lowered compared to conventional urethane (meth)acrylates. That is, the increase in viscosity can be suppressed, and a composition with excellent modeling properties can be obtained. Furthermore, it has been found that (a) a (meth)acrylic polymerizable compound having an allophanate group exhibits excellent transparency, high recovery force against deformation from external forces, and excellent impact resistance when used as a material for 3D printers. That is, it is possible to impart toughness and transparency to a molded object. In addition, it has been found that (a) a (meth)acrylic polymerizable compound having an allophanate group can be combined with (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups to further suppress the increase in viscosity and obtain a composition with excellent modeling properties. In this specification, the "allophanate group" refers to the structure "-NH-CO-N-CO2-". The inclusion of an allophanate group in the molecule can suppress an increase in viscosity and provide a composition with excellent moldability, and can also impart toughness and transparency to molded objects.

[0036] The (a) allophanate group-containing (meth)acrylic polymerizable compound may be contained in the photopolymerizable composition in an amount of 30 to 99% by weight, 35 to 90% by weight, or 40 to 80% by weight. If the (a) allophanate group-containing (meth)acrylic polymerizable compound is less than 30% by weight, a problem may occur in that it is difficult to impart toughness to a molded object. If the (a) allophanate group-containing (meth)acrylic polymerizable compound is more than 99% by weight, a problem may occur in that the viscosity is high and molding is difficult.

[0037] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups may be contained in the photopolymerizable composition in an amount of 1 to 70% by weight, 10 to 65% by weight, or 20 to 60% by weight. (b) If the (meth)acrylic polymer having one or two (meth)acryloyloxy groups is less than 1% by weight, the viscosity may be high and it may be difficult to mold. (b) If the (meth)acrylic polymer having one or two (meth)acryloyloxy groups is more than 70% by weight, it may be difficult to impart toughness.

[0038] The photopolymerization initiator (c) may be contained in an amount of 0.01 to 5 parts by weight, 0.5 to 5 parts by weight, or 1.0 to 4 parts by weight, per 100 parts by weight of the total of (a) the (meth)acrylic polymerizable compound having an allophanate group and (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups. If the amount of the photopolymerization initiator (c) is less than 0.01 part by weight, the composition is difficult to cure, and problems with modeling may occur, whereas if the amount exceeds 5 parts by weight, the transparency of the modeled object may deteriorate.

[0039] The (a) allophanate group-containing (meth)acrylic polymerizable compound desirably has a viscosity of 60,000 mPa s or less, more preferably 50,000 mPa s or less, and most preferably 40,000 mPa s or less, as measured with a rotational rheometer at a temperature of 23° C. and a rotation speed of 20 rpm. This makes it possible to suppress an increase in the viscosity of the polymerizable composition and to obtain a photopolymerizable composition with excellent shapeability.

[0040] The (a) allophanate group-containing (meth)acrylic polymerizable compound may have a glass transition point of a cured product of not more than 120° C. By appropriately selecting the glass transition point, optimal toughness can be imparted to a shaped article.

[0041] (a) The (meth)acrylic polymerizable compound having an allophanate group can have three or more (meth)acryloyloxy groups, which can impart suitable toughness and strength to a shaped object.

[0042] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups can be composed of a (meth)acrylate polymerizable monomer that does not contain a urethane structure. In this specification, the "urethane bond" refers to the structure "-NH-CO-O-". By using a (meth)acrylate that does not contain a urethane structure, it is possible to suppress an increase in the viscosity of the polymerizable composition and to impart toughness and transparency to the molded object.

[0043] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups may contain at least one (meth)acrylic polymer having two (meth)acryloyloxy groups. If the (meth)acrylic polymer having two (meth)acryloyloxy groups is not contained, the shaped object may become soft.

[0044] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups may contain 1 to 25 parts by weight of the (meth)acrylic polymer having one (meth)acryloyloxy group. If the (meth)acrylic polymer having one (meth)acryloyloxy group exceeds 25 parts by weight relative to a total of 100 parts by weight of (a) the (meth)acrylic polymerizable compound having an allophanate group and (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups, the molded object may become soft, which may cause problems. If the (meth)acrylic polymer having one (meth)acryloyloxy group is less than 1 part by weight, the toughness is unlikely to be improved, and it may be difficult to impart softness.

[0045] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups may include a (meth)acrylic polymer containing one or more reactive groups selected from the group consisting of a hydroxyl group and a carboxylic acid group. The intermolecular interaction in the polymerizable composition can adjust the viscosity and impart toughness and strength to the shaped object.

[0046] (c) The photopolymerization initiator may be one or more selected from the group consisting of alkylphenone compounds, acetophenone compounds, and acylphosphine oxide compounds. Taking into consideration the formability and physical properties of the polymerizable composition, a plurality of photopolymerization initiators may be combined.

[0047] The photopolymerizable composition may have a viscosity of 10,000 mPa s or less as measured with a rotational rheometer at a temperature of 23°C and a rotation speed of 20 rpm. If the viscosity is too high, problems with moldability may occur.

[0048] The photopolymerizable composition may have a glass transition point of 30 to 100° C. in this range, which can impart toughness and strength to a shaped object.

[0049] (a) The (meth)acrylic polymerizable compound having an allophanate group is not particularly specified, and a material synthesized by a known method can be used. More specifically, it is formed by the reaction of a diisocyanate with an alcohol, and is formed by adding a diisocyanate to a urethane group. The structure can be controlled by changing the hydroxyl group equivalent molecular weight of the polyalcohol and the molecular weight of the polyisocyanate.

[0050] For example, it can be formed by reacting hexamethylene diisocyanate with a monohydric to hexahydric alcohol having a molecular weight of 32 to 900 or a mixture of such alcohols. Other examples of isocyanates include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate (HDI), undecamethylene diisocyanate, dodecamethylene diisocyanate, 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (IPDI), 4,4'-bis-(isocyanatocyclohexyl)methane, and the like.

[0051] Also suitable are saturated monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, methoxypropanol, and isomeric butanols, pentanols, hexanols, octanols, decanols, dodecanols, and octadecanols. Examples of polyhydric alcohols include ethylene glycol, propylene glycol, butanediol-1,4, hexanediol-1,6, neopentyl glycol, 2-methylpropanediol-1,3, 2,2,4-trimethylpentanediol-1,3, dimeric fatty alcohols, trimeric fatty alcohols, glycerol, trimethylolpropane, trimethylolethane, isomeric hexanetriols, pentaerythritol, and sorbitol. Also suitable are unsaturated alcohols such as allyl alcohol, trimethylolpropane diallyl ether, butenediol, and monofunctional alcohols derived from the corresponding acids and acid mixtures of unsaturated synthetic and natural fatty acids.

[0052] (a) A specific example of a (meth)acrylic polymerizable compound having an allophanate group is an allophanate group-containing (meth)acrylate resin. An allophanate group-containing (meth)acrylate resin has a "-N(COOR)" group in the resin skeleton. 1 )-CO-NH-" and further includes a structure consisting of an allophanate group represented by the formula "-NH-COOR 2 -O-CO-C(=CH 2 )-R 3" The allophanate group-containing (meth)acrylate resin having such a structure can be obtained by reacting an allophanate group-containing polyisocyanate resin with an active hydrogen compound having at least one (meth)acrylate group in the molecule.

[0053] Here, "-N(COOR 1 )-CO-NH-" in which R 1 represents an aliphatic, alicyclic, or aromatic hydrocarbon group having a total of 1 to 40 carbon atoms. However, these hydrocarbon groups may be branched or may have a substituent.

[0054] Also, "-NH-COOR 2 -O-CO-C(=CH 2 )-R 3 " In the formula, R 2 represents an organic group having a total of 1 to 50 carbon atoms, and R 3 represents a hydrogen atom or a methyl group, provided that the organic group R2 may have a branch or a side chain.

[0055] <Allophanate group-containing polyisocyanate resin> The allophanate group-containing polyisocyanate resin can be produced by reacting a monoalcohol with an organic polyisocyanate prepolymer under specific conditions.

[0056] <<Production of organic polyisocyanate prepolymer>> The organic polyisocyanate prepolymer means a prepolymer having an isocyanate group, and can usually be produced by reacting an isocyanate compound with a hydroxyl group-containing compound.

[0057] The isocyanate compound used in the reaction for producing the organic polyisocyanate prepolymer can usually be divided into a diisocyanate compound and a polyisocyanate compound. The polyisocyanate compound means an isocyanate compound having three or more isocyanate groups.

[0058] Examples of the diisocyanate compound include: Aliphatic diisocyanate compounds such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate; Alicyclic diisocyanate compounds such as 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 1,3-diisocyanatomethylcyclohexane (H6 XDI), and isophorone diisocyanate (IPDI); Aromatic aliphatic diisocyanate compounds such as 1,3- or 1,4-xylylene diisocyanate, mixtures of the two compounds, ω,ω'-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene, mixtures of the two compounds; and Aromatic diisocyanate compounds such as m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, and toluene diisocyanate (TDI); etc.

[0059] Examples of the polyisocyanate compound include: Aliphatic polyisocyanate compounds such as lysine ester triisocyanate, 1,4,8-triisocyanatooctane, 1,6,11-triisocyanatoundecane, 1,8-diisocyanato-4-isocyanatomethyloctane, 1,3,6-triisocyanatohexane, 2,5,7-trimethyl-1,8-diisocyanato-5-isocyanatomethyloctane; 1,3,5-Triisocyanatocyclohexane, 1,3,5-Trimethylisocyanatocyclohexane, 2-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 2-(3-isocyanatopropyl)-2,6-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 3-(3-isocyanatopropyl)-2,5-di(isocyanatomethyl)-bicyclo(2.2.1)heptane, 5-(2-isocyanatoethyl)-2-isocyanatomethyl-3-(3 -isocyanatepropyl)-bicyclo(2.2.1)heptane, 6-(2-isocyanateethyl)-2-isocyanatemethyl-3-(3-isocyanatepropyl)-bicyclo(2.2.1)heptane, 5-(2-isocyanateethyl)-2-isocyanatemethyl-2-(3-isocyanatepropyl)-bicyclo(2.2.1)heptane, 6-(2-isocyanateethyl)-2-isocyanatemethyl-2-(3-isocyanatepropyl)-bicyclo(2.2.1)heptane and other alicyclic polyisocyanate compounds; Aromatic and aliphatic polyisocyanate compounds such as 1,3,5-triisocyanate methylbenzene; and Aromatic polyisocyanate compounds such as triphenylmethane-4,4',4''-triisocyanate, 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, 4,4'-diphenylmethane-2,2',5,5'-tetraisocyanate; etc.

[0060] These isocyanate compounds may be used alone or in combination of two or more. Among these isocyanate compounds, hexamethylene diisocyanate (HDI), 1,3-diisocyanatomethylcyclohexane (H6XDI), and isophorone diisocyanate (IPDI) are preferred.

[0061] Examples of the hydroxyl group-containing compound used in the reaction for producing the organic polyisocyanate prepolymer include: Monoalcohols (monohydric alcohols) such as methanol, ethanol, propanol, butanol, alkanols having 5 to 38 carbon atoms, alkenyl alcohols having 3 to 36 carbon atoms (e.g., 2-propen-1-ol, etc.), alkadienols having 6 to 8 carbon atoms (e.g., 3,7-dimethyl-1,6-octadien-3-ol, etc.), and aliphatic unsaturated alcohols having 9 to 24 carbon atoms other than the above; Dialcohols (dihydric alcohols) such as ethylene glycol, propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,6-hexanediol, methylpentanediol, neopentyl glycol, 3,3-dimethylolheptane, alkanediols having 7 to 22 carbon atoms, diethylene glycol, triethylene glycol, dipropylene glycol, cyclohexanedimethanol, alkane-1,2-diols having 17 to 20 carbon atoms, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, and bisphenol A; Trialcohols (trihydric alcohols) such as glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, 1,1,1-tris(hydroxymethyl)propane, 2,2-bis(hydroxymethyl)-3-butanol, and other aliphatic triols having 8 to 24 carbon atoms; Alcohols with tetrahydric or higher hydricities, such as tetramethylolmethane, D-sorbitol, xylitol, D-mannitol, and D-mannite; polyester polyols such as pivalic acid neopentyl glycol ester; Polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol; and polycarbonate polyols such as polyhexamethylene carbonate glycol; etc.

[0062] Among these compounds having a hydroxyl group, monoalcohols or dialcohols are preferred. These compounds having a hydroxyl group may be used alone or in combination of two or more kinds.

[0063] When the hydroxyl group compound is a monoalcohol, the organic polyisocyanate prepolymer can be obtained by reacting the monoalcohol with the isocyanate compound in an amount that provides an excess of isocyanate group equivalents relative to twice the hydroxyl group equivalent of the monoalcohol, or by reacting the hydroxyl group-containing compound with the isocyanate compound in an amount that provides an excess of isocyanate group equivalents relative to the hydroxyl group equivalent of the hydroxyl group-containing compound when the hydroxyl group compound is other than a monoalcohol, and further removing unreacted isocyanate compound as necessary.

[0064] <<Production of allophanate group-containing polyisocyanate resin>> The allophanate group-containing polyisocyanate resin can be obtained by reacting an organic polyisocyanate prepolymer with a monoalcohol under specific reaction conditions. As a method for producing the allophanate group-containing polyisocyanate resin, for example, the methods disclosed in detail in JP-A-5-209038 and JP-A-8-188566 can be adopted.

[0065] That is, the allophanate group-containing polyisocyanate resin can be obtained by subjecting a monoalcohol and the above-mentioned organic polyisocyanate prepolymer in an amount that results in an excess of an isocyanate group equivalent relative to the hydroxyl group equivalent in the monoalcohol to an allophanate reaction in the presence of a catalyst, and further removing the unreacted organic polyisocyanate prepolymer.

[0066] By these reactions, monoalcohols can be bonded to the organic polyisocyanate prepolymer via the allophanate groups, and the solubility in acrylic resins and polyester resins can be dramatically improved. Moreover, the skeleton derived from the monoalcohol can impart flexibility to the cured product obtained by using the resin, and thus flexibility and scratch resistance can be achieved at the same time.

[0067] The monoalcohol used in the above-mentioned production process may have an unsaturated bond or a polar group such as an ether group or an ester group. The above-mentioned monoalcohol can be appropriately selected and used depending on the other resin to be compatible with.

[0068] Among these monoalcohols, it is preferable to use monoalcohols having a carbon number of 1 to 40. By using a monoalcohol having a carbon number within the above range, it is possible to achieve both flexibility and scratch resistance of the cured coating film.

[0069] These monoalcohols include: aliphatic, alicyclic, and aromatic aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, butanol isomers, allyl alcohol, pentanol, hexanol, heptanol, 2-ethylhexanol, n-octanol, nonanol, n-decanol, cyclopentanol, cyclohexanol, furfuryl alcohol, and benzyl alcohol; Ether group-containing monoalcohols which are addition polymers of the above monoalcohols with alkylene oxides such as ethylene oxide and propylene oxide (random and / or block copolymers of two or more alkylene oxides); Ester group-containing monoalcohols which are addition polymers of low molecular weight monoalcohols and lactones such as ε-caprolactone, δ-valerolactone, and the like; and ester group-containing monoalcohols which are adducts of monocarboxylic acids such as acetic acid, propionic acid, and benzoic acid with alkylene oxides; The following can be given as examples:

[0070] In addition to the above-mentioned monoalcohols having 1 to 40 carbon atoms, small amounts of polyfunctional alcohols such as dialcohols and trialcohols can be used in combination. Furthermore, other than these, active hydrogen compounds such as thiols, oximes, lactams, phenols, and β-diketones can also be used in combination as necessary.

[0071] Furthermore, prior to carrying out the allophanate reaction between the organic polyisocyanate prepolymer and the monoalcohol, some or all of the hydroxyl groups present in the monoalcohol may be preliminarily reacted with some of the isocyanate groups present in the organic polyisocyanate compound to generate urethane groups.

[0072] The proportion of the organic polyisocyanate prepolymer and the monoalcohol used, calculated as the molar ratio of the isocyanate groups present in the organic polyisocyanate prepolymer to the hydroxyl groups present in the monoalcohol ([isocyanate groups in the prepolymer] / [hydroxyl groups in the monoalcohol]), is usually in the range of 5 to 100, preferably 10 to 50. When the molar ratio of the isocyanate groups to the hydroxyl groups is within the above range, the content of allophanate groups becomes appropriate, and a resin having high solubility in other resins can be obtained.

[0073] The reaction between the monoalcohol and the organic polyisocyanate compound may or may not involve the use of a solvent. If a solvent is used, it is necessary to use a solvent that has no reactivity with the isocyanate group.

[0074] As a catalyst for the reaction of the monoalcohol with the organic polyisocyanate prepolymer, a catalyst is used which allows easy control of the reaction, reduces the coloring of the final product, and reduces the production of dimers with poor thermal stability. Examples of such catalysts include: tetramethylammonium, tetraethylammonium, tetrabutylammonium, trimethylbenzylammonium, and other tetraalkylammonium hydroxides and their organic weak acid salts; Trimethylhydroxypropylammonium, trimethylhydroxyethylammonium, triethylhydroxypropylammonium, triethylhydroxyethylammonium and other trialkylhydroxyalkylammonium hydroxides and their organic weak acid salts; Alkyl carboxylates of alkyl carboxylic acids such as acetic acid, caproic acid, octylic acid, myristic acid, etc. with alkali metals; Metal alkylcarboxylates of the above alkylcarboxylic acids with metals such as tin, zinc, lead, etc.; Chelate compounds of β-diketones with metals, such as aluminum acetylacetone and lithium acetylacetone; Friedel-Crafts catalysts such as aluminum chloride and boron trifluoride; Various organometallic compounds such as titanium tetrabutylate, tributylantimony oxide, and the like; and Aminosilyl group-containing compounds such as hexamethylsilazane; Some examples include:

[0075] Of these catalysts, quaternary ammonium compounds such as tetraalkylammonium hydroxide and its weak organic acid salt, trialkylhydroxyalkylammonium hydroxide and its weak organic acid salt, etc. are preferably used.

[0076] The catalyst is usually used in an amount of 0.0001 to 1% by weight based on the organic polyisocyanate, although this varies depending on the type and reaction temperature, etc. The allophanate reaction is usually carried out at a temperature of 20 to 160°C, preferably 40 to 100°C.

[0077] When the residual NCO amount reaches a desired amount, an acidic substance such as phosphoric acid, benzoyl chloride, monochloroacetic acid, or dodecylbenzenesulfonic acid is added to the reaction mixture as a catalyst deactivator to deactivate the catalyst, and then the unreacted organic polyisocyanate prepolymer is removed by means of, for example, thin-film distillation, to obtain a desired polyisocyanate resin.

[0078] The polyisocyanate resin having allophanate groups thus obtained can be made into a resin that can be mixed with other resins in any ratio by appropriately selecting the monoalcohol as the raw material, and it is possible to provide a resin that does not become cloudy even at or below room temperature.

[0079] The allophanate group-containing polyisocyanate resin can also be obtained by reacting the isocyanate compound used in the production of the above-mentioned organic polyisocyanate prepolymer with a monoalcohol, which is a compound having a hydroxyl group, under conditions in which the isocyanate compound is in large excess.

[0080] <Production of Allophanate Group-Containing (Meth)acrylate Resin> The allophanate group-containing (meth)acrylate resin is obtained by reacting the allophanate group-containing polyisocyanate resin with an active hydrogen compound having at least one (meth)acrylate group in the molecule. As the active hydrogen compound having a (meth)acrylate group used in this reaction, a compound containing a (meth)acrylate group and a hydroxyl group can be suitably used.

[0081] (a) The (meth)acrylic polymerizable compound having an allophanate group is not particularly specified, and a material synthesized by a known method can be used. For example, hexane, 1,6-diisocyanate, homopolymer, 2-hydroxyethyl acrylate block, hexane, 1,6-diisocyanate, homopolymer, 2-hydroxyethyl acrylate, propylene glycol monoacrylate block, etc. can be mentioned. These may be used alone or in combination of two or more kinds.

[0082] In addition, the (a) allophanate group-containing (meth)acrylic polymerizable compound is represented by the general formula "R 1 N(COOR 2 )CONHCOR 3 " is a compound represented by the formula: R in the formula 1 is a trifluoromethylbenzene group, R 2 is a methylbenzene group, R 3 is a morpholine group, R in the formula 1 is a trifluoromethylbenzene group, R 2 is a methylbenzene group, R 3 is a methoxy group, R in the formula 1 is a trifluoromethylbenzene group, R 2 is a methylbenzene group, R 3 is a hexanol group, R in the formula 1 is a trifluoromethylbenzene group, R 2 is a benzene group, R 3 is a morpholine group, R in the formula 1 is a trifluoromethylbenzene group, R 2 is a chlorobenzene group, R 3 is a decanol group, and R in the formula 1 is a dichlorobenzene group, R 2 is a benzene group, R 3 is a toluidine group, etc.

[0083] Specific examples of the (meth)acrylic polymerizable compound having an allophanate group (a) having three or more (meth)acryloyloxy groups include the compounds used in the examples of this specification.

[0084] (b) (meth)acrylic polymers having one or two (meth)acryloyloxy groups, examples of (meth)acrylic polymers having two (meth)acryloyloxy groups include ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, 2,2-bis[4-(methacryloxyethoxy)phenyl]propane, tricyclodecane dimethanol dimethacrylate, 1,10-decane diol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-nonanediol dimethacrylate, neopentyl glycol dimethacrylate, 2-hydroxy-1,3-dimethacryloxypropane, etc. Among these, triethylene glycol dimethacrylate and 2,2-bis(4-methacryloxypolyethoxyphenyl)propane are preferred.

[0085] (b) (meth)acrylic polymers having one or two (meth)acryloyloxy groups. Examples of (meth)acrylic polymers having one (meth)acryloyloxy group include, for example, o-benzyl (meth)acrylate, m-phenoxybenzyl (meth)acrylate, p-phenoxybenzyl (meth)acrylate, 2-(o-phenoxyphenyl)ethyl (meth)acrylate, 2-(m-phenoxyphenyl)ethyl (meth)acrylate, 2-(p-phenoxyphenyl)ethyl (meth)acrylate, 3-(o- phenoxyphenyl)propyl (meth)acrylate, 3-(m-phenoxyphenyl)propyl (meth)acrylate, 3-(p-phenoxyphenyl)propyl (meth)acrylate, 4-(o-phenoxyphenyl)butyl (meth)acrylate, 4-(m-phenoxyphenyl)butyl (meth)acrylate, 4-(p-phenoxyphenyl)butyl (meth)acrylate, 5-(o-phenoxyphenyl)pentyl (meth)acrylate, 5-(m-phenoxyphenyl)pentyl (meth)acrylate, 5-(p-phenoxyphenyl) (phenyl)pentyl (meth)acrylate, 6-(o-phenoxyphenyl)hexyl (meth)acrylate, 6-(m-phenoxyphenyl)hexyl (meth)acrylate, 6-(p-phenoxyphenyl)hexyl (meth)acrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, alkyl methacrylate, n-stearyl methacrylate, butoxydiethylene glycol methacrylate , methoxypolyethylene glycol methacrylate, cyclohexyl methacrylate, tetrahydrofurfuryl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, 2-methacryloyloxyethyl succinic acid, glycidyl methacrylate, etc. These may be used alone or in combination of two or more.

[0086] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups may be a (meth)acrylate polymerizable monomer not containing a urethane structure. Specific examples of (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups not containing a urethane structure include 3,3,5-trimethylcyclohexyl acrylate, isobornyl acrylate, dicyclopentanyl acrylate, cyclohexyl methacrylate, tert-butyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenoxybenzyl acrylate, and triethylene glycol dimethacrylate.

[0087] (b) Specific examples of (meth)acrylic polymers having one or two (meth)acryloyloxy groups and containing one or more reactive groups selected from the group consisting of hydroxyl groups and carboxylic acid groups include hydroxy linear alkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, mono-2-(methacryloyloxy)ethyl succinate, and 4-hydroxybutyl (meth)acrylate, caprolactone-modified hydroxy (meth)acrylate, hydroxy branched alkyl (meth)acrylate, and hydroxyl group-containing (meth)acrylates such as mono(meth)acrylate of polyester diol obtained from divalent carboxylic acid (such as phthalic acid) and dihydric alcohol (such as propylene glycol), monocarboxylic acid such as acrylic acid, methacrylic acid, and crotonic acid, and tricarboxylic acid such as 1,2,4-benzenetricarboxylic acid 4-[2-(methacryloyloxy)ethyl]. These may be used alone or in combination of two or more.

[0088] (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups may be used alone or in combination of two or more kinds.

[0089] (c) Examples of the photopolymerization initiator include alkylphenone compounds, acetophenone compounds, acylphosphine oxide compounds, titanocene compounds, oxime ester compounds, benzoin compounds, benzophenone compounds, thioxanthone compounds, α-acyloxime ester compounds, phenylglyoxylate compounds, benzyl compounds, azo compounds, diphenyl sulfide compounds, organic dye compounds, iron-phthalocyanine compounds, benzoin ether compounds, anthraquinone compounds, α-diketones, ketals, coumarins, and α-aminoketone compounds. Among these, alkylphenone compounds, acetophenone compounds, and acylphosphine oxide compounds are preferred from the viewpoint of reactivity and the like. These may be used alone or in combination of two or more.

[0090] Specific examples of alkylphenone compounds used as photopolymerization initiators include 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, and the like.

[0091] Specific examples of acetophenone-based compounds used as photopolymerization initiators include acetophenone, 2-hydroxy-2-phenylacetophenone, 2-ethoxy-2-phenylacetophenone, 2-methoxy-2-phenylacetophenone, 2-isopropoxy-2-phenylacetophenone, 2-i-butoxy-2-phenylacetophenone, 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one, and the like.

[0092] Specific examples of the acylphosphine oxide compound used as the photopolymerization initiator 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, and benzoyldi-(2,6-dimethylphenyl)phosphonate. Examples of the bisacylphosphine oxides 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, and (2,5,6-trimethylbenzoyl)-2,4,4-trimethylpentylphosphine oxide.

[0093] In addition, the stereolithography composition of the present invention can be blended with known additives. For the purpose of adjusting the color tone or paste properties, the additives include, for example, pigments or dyes as colorants, organic solvents, thickeners, ultraviolet absorbers, polymerization inhibitors, fluorescent agents, inorganic fillers, etc., and in this case, the additives can be added in an amount of 0.0001 to 30 parts by weight based on the total weight of the composition. In particular, it is preferable that the composition contains 0.0001 to 2 parts by weight of one or more additives selected from colorants, ultraviolet absorbers, polymerization inhibitors, and fluorescent agents based on the total weight of the composition. In the present invention, the composition may contain no additives other than pigments, dyes, organic solvents, thickeners, ultraviolet absorbers, polymerization inhibitors, fluorescent agents, and inorganic fillers.

[0094] For the purpose of viscosity adjustment, etc., additives that can be used include (meth)acrylic polymerizable compounds that do not contain allophanate groups, acrylic resins, polyester resins, epoxy resins, melamine resins, olefin resins, etc. In the present invention, additives other than compounds having (meth)acrylic groups, acrylic resins, polyester resins, epoxy resins, melamine resins, and olefin resins can be used.

[0095] Specific examples of such compounds having a (meth)acrylic group include 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isobornyl (meth)acrylate, dipropylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, dicyclopentenyl (meth)acrylate, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dimethyloltricyclodecane di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, neopentyl glycol modified trimethylolpropane di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol Examples of the (meth)acrylate include ricol di(meth)acrylate, polyethylene glycol di(meth)acrylate, bis((meth)acryloxyethyl)bisphenol A, trimethylolpropane tri(meth)acrylate, ethylene oxide modified trimethylolpropane di(meth)acrylate, propylene oxide modified trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, ethylene oxide modified glycerin tri(meth)acrylate, propylene oxide modified glycerin tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, and polyfunctional (meth)acrylates in which a portion of these (meth)acrylate compounds is substituted with an alkyl group or ε-caprolactone.

[0096] Further examples include polyester poly(meth)acrylates obtained by reacting a polybasic acid such as phthalic acid or adipic acid with a polyhydric alcohol such as ethylene glycol or butanediol and a (meth)acrylic acid compound; epoxy poly(meth)acrylates obtained by reacting an epoxy resin with a (meth)acrylic acid compound; polysiloxane poly(meth)acrylates obtained by reacting a polysiloxane with a (meth)acrylic acid compound; and polyamide poly(meth)acrylates obtained by reacting a polyamide with a (meth)acrylic acid compound.

[0097] Furthermore, in the present invention, various additives such as organic solvents, polymerization inhibitors, ultraviolet absorbers, light stabilizers, antioxidants, anti-yellowing agents, dyes, pigments, leveling agents, defoamers, thickeners, anti-settling agents, antistatic agents, anti-fogging agents, anti-repelling agents, wetting agents, dispersants, anti-sagging agents, coupling agents, etc. In the present invention, it is possible to not contain any additives other than those described in this specification.

[0098] The dental photopolymerizable composition for 3D printers of the present invention can be used for producing, for example, dental products, dental aligner materials, denture base materials, and dental mouthpieces, but is not limited thereto. EXAMPLES

[0099] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples in any way.

[0100] [(a) (Meth)acrylic polymerizable compound having an allophanate group] (a1) (Meth)acrylic polymerizable compound having an allophanate group 1 A polyisocyanate resin was produced from 1,6-hexamethylene diisocyanate and 1,3-butanediol. Specifically, it was produced by the method disclosed in Comparative Example 1 of JP-A-6-41270. The produced polyisocyanate resin had an NCO content of 20.8 wt%. In addition, NMR analysis confirmed almost no urethane groups, 5 mol% allophanate groups, and 95 mol% isocyanurate groups. Next, 600 g of this polyisocyanate resin, 149 g 2-hydroxyethyl methacrylate, 127 g pentaerythritol triacrylate, and 2 g methylhydroquinone were charged into a reaction vessel and reacted at 80° C. for 4 hours under air flow. 0.6 g of dibutyltin laurate was added to this and further reacted at 80° C. for 4 hours to obtain (a1) (meth)acrylic polymer 1 having an allophanate group. In addition, d6-DMSO was used as a solvent and H 1 The content of allophanate groups determined by -NMR measurement was 0.2 mmol / g. Furthermore, the viscosity measured using a rotational rheometer was 9000 mPa·s. The glass transition point was 47°C. It was confirmed that the resulting resin had three or more functional groups.

[0101] (a2) (Meth)acrylic polymerizable compound having an allophanate group 2 A polyisocyanate resin was produced from 1,3-diisocyanatomethylcyclohexane and isobutanol. Specifically, it was produced by the method disclosed in Example 1 of JP-A-6-41270. The produced polyisocyanate resin had an NCO content of 18.2 wt%. In addition, NMR analysis confirmed almost no urethane groups, 35 mol% allophanate groups, and 75 mol% isocyanurate groups. Next, 600 g of this polyisocyanate resin, 241 g 2-hydroxyethyl acrylate, 206 g pentaerythritol triacrylate, and 2 g methylhydroquinone were charged into a reaction vessel and reacted at 80° C. for 4 hours under air flow. 0.6 g of dibutyltin laurate was added to this and further reacted at 80° C. for 4 hours to obtain (a2) a (meth)acrylic polymer 2 having an allophanate group. In addition, d6-DMSO was used as a solvent and H 1The content of allophanate groups determined by -NMR measurement was 1.0 mmol / g. Furthermore, the viscosity measured using a rotational rheometer was 60,000 mPa·s. The glass transition point was 98°C. It was confirmed that the resulting resin had three or more functional groups.

[0102] (a3) (Meth)acrylic polymerizable compound having an allophanate group 3 A polyisocyanate resin was produced from isophorone diisocyanate and isobutanol. Specifically, it was produced by the method disclosed in Example 4 of JP-A-6-41270. The produced polyisocyanate resin had an NCO content of 11.6 wt%. In addition, urethane groups were hardly confirmed by NMR analysis, and allophanate groups were 60 mol% and isocyanurate groups were 40 mol%. Next, 600 g of this polyisocyanate resin, 149 g of 2-hydroxyethyl acrylate, 127 g of pentaerythritol triacrylate, and 2 g of methylhydroquinone were charged into a reaction vessel and reacted at 80°C for 4 hours under air flow. 0.6 g of dibutyltin laurate was added to this and further reacted at 80°C for 4 hours to obtain (a3) ​​a (meth)acrylic polymer 3 having an allophanate group. In addition, d6-DMSO was used as a solvent and H 1 The content of allophanate groups determined by -NMR measurement was 0.5 mmol / g. Furthermore, the viscosity measured using a rotational rheometer was 32,000 mPa·s. The glass transition point was 120°C. It was confirmed that the resin obtained had three or more functional groups.

[0103] (a4) (Meth)acrylic polymerizable compound having an allophanate group 4 Hexane, 1,6-diisocyanate, homopolymer, 2-hydroxyethyl acrylate block was used. The viscosity measured using a rotational rheometer is 60,000 mPa·s. The glass transition point is 98°C, and it is a tetrafunctional allophanate group-containing acrylate resin.

[0104] (a5) (Meth)acrylic polymerizable compound having an allophanate group 5 Hexane, 1,6-diisocyanate, homopolymer, 2-hydroxyethyl acrylate, propylene glycol monoacrylate block was used. The viscosity measured using a rotational rheometer is 30000mPa·s. The glass transition point is 118℃, and it is an allophanate group-containing acrylate resin with three functionalities.

[0105] [(b) (meth)acrylic polymer having one or two (meth)acryloyloxy groups] <(Meth)acrylic polymer having one (meth)acryloyloxy group and not containing a urethane structure> (b1) Mono-2-(methacryloyloxy)ethyl succinic acid (b2) 3-phenoxybenzyl acrylate

[0106] <(Meth)acrylic polymer having two (meth)acryloyloxy groups and not containing a urethane structure> (b3) Triethylene glycol dimethacrylate

[0107] <(Meth)acrylic polymer having two (meth)acryloyloxy groups with a urethane structure> (b4): Di(methacryloxyethyl)trimethylhexamethylenediurethane

[0108] [(Meth)acrylic polymer having three (meth)acryloyloxy groups] Trimethylolpropane Trimethacrylate

[0109] [(c) Photopolymerization initiator] <Acylphosphine oxide compounds> (c1) Monoacylphosphine oxide

[0110] <Acetophenone compounds> (c2) 2-Hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one

[0111] [(d) (Meth)acrylic polymerizable compound not containing an allophanate group] (d1) Di(methacryloxyethyl)trimethylhexamethylenediurethane

[0112] [Preparation of composition for stereolithography] As shown in the Examples Table, a given amount of each component including (a) a (meth)acrylic polymerizable compound having an allophanate group, (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups, and (c) a photopolymerization initiator was added to a container and mixed using a planetary centrifugal mixer ARV-310 (Thinky Corporation), to prepare a photopolymerizable composition.

[0113] [Viscosity measurement method] The viscosity of the photopolymerizable composition was measured using a rotational rheometer (Physica MCR301, manufactured by Anton Paar) at a temperature of 23° C. and a rotation speed of 20 rpm.

[0114] [Glass transition temperature measurement method] Measurements were performed in tension mode using a DMA Q800 (TA Instruments) with a sample length of 20 mm. The stereolithography composition was poured into a mold (width 10 mm x thickness 1 mm x length 50 mm) and polymerized and cured using a photopolymerizer (Solidlight LED, Matsukaze) to prepare a sample. The glass transition point (Tg) of the sample was measured from the peak top temperature of the loss tangent (tan δ).

[0115] [Formability] The photopolymerizable composition obtained in the above [Preparation of photopolymerization composition] was molded into various test specimen shapes using a dental 3D printer DWP-80S (manufactured by DG SHAPE). After molding, the molded object was washed with ethanol for 10 minutes and dried. After storing for 24 hours, post-polymerization was performed for 10 minutes using a photopolymerizer (Solidlight LED, manufactured by Matsukaze). The surface of the test object was visually inspected, and those without molding defects were rated as good (A), those that could be molded despite slight surface roughness were rated as possible (B), and those whose surface was significantly rough or it was difficult to obtain a molded object were rated as C.

[0116] [Impact resistance] The photopolymerization composition was poured into a mold (width 4 mm x thickness 6 mm x length 50 mm), polymerized and hardened using a photopolymerizer (Solidlight LED, manufactured by Matsukaze), and a V-shaped notch was machined with a milling machine aiming for a depth of 1.2 mm to prepare a test specimen. Using an impact tester IMPACT TESTER (manufactured by Toyo Seiki), the load at which the test specimen broke was measured with a hammer capacity of 0.5 J. The measured value was expressed in J / m 2 The average value was calculated as the impact resistance. 2 The above items were judged to have excellent impact resistance.

[0117] [Color tone] According to the above test method for [Formability], a plate-shaped specimen with a diameter of 15 mm and a thickness of 1.0 mm was prepared. After preparation, the specimen was stored at room temperature for 14 days. The L*a*b values ​​were measured against a white background using a spectrophotometer (CM-3500d: Konica Minolta). Those with a b* value of 4 or less were deemed good because they had very little yellowing and were very transparent, those with a b* value of 10 or less were deemed usable because they had very little yellowing and were very transparent, and those with a b* value of more than 10 were deemed unsuitable.

[0118] [Table 1]

[0119] [Table 2]

[0120] [Table 3]

[0121] [Details of each composition] Examples 1 to 17 and 25 to 27 in the table were found to have high impact resistance and good toughness, and the color tone (b* value) was also found to be 5.5 or less, indicating excellent transparency.

[0122] Example 18 in the table had low impact resistance and slightly decreased toughness due to the small amount of (a) (meth)acrylic polymerizable compound having an allophanate group, and also had a high glass transition point, but was found to have good physical properties overall.

[0123] In Example 19 in the table, (c) the amount of photopolymerization initiator was small, which made curing difficult and reduced the moldability slightly, but it was found to exhibit good physical properties overall.

[0124] Example 20 in the table showed a tendency for the color tone (b* value) to be high due to the large amount of (c) photopolymerization initiator, but was found to exhibit good physical properties overall.

[0125] Example 21 in the table is the case where (a) the (meth)acrylic polymerizable compound having an allophanate group has a glass transition point of 120° C. Although the impact resistance was low, the toughness was slightly decreased, and the color tone (b* value) tended to be high, it was recognized that the physical properties were good overall.

[0126] Example 22 in the table is a case where (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups contains a urethane structure. The viscosity of the stereolithography composition increased and the modeling property decreased slightly, but it was found to show good physical properties overall.

[0127] Example 23 in the table is a case where (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups is composed of only a (meth)acrylic polymer having one (meth)acryloyloxy group and is contained in a large amount. The molded object became soft and the moldability was slightly decreased, but it was observed that the physical properties were good overall.

[0128] Example 24 in the table is a case where the viscosity of the stereolithography composition was high. Although the modeling ability was reduced, it was found that the physical properties were good overall.

[0129] Comparative Example 1 is a case where (a) a (meth)acrylic polymerizable compound having an allophanate group is not included. Impact resistance was low and toughness could not be imparted. In addition, the color tone (b* value) was high and transparency was poor, and good physical properties could not be obtained overall.

[0130] Comparative Example 2 is a case where (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups is not included, and only a (meth)acrylic polymer having a polyfunctional (meth)acryloyloxy group is included. Impact resistance was low, and toughness could not be imparted. In addition, the color tone (b* value) was high, transparency was poor, and good physical properties could not be obtained overall.

[0131] It was confirmed that the same results were obtained in each example even when 0.1 parts by weight of a colorant and an ultraviolet absorbing agent were further included in the components. [Industrial Applicability]

[0132] The present invention is utilized in the industry of manufacturing dental restorations with 3D printers using photopolymerizable compositions.

Claims

1. (a) a (meth)acrylic polymerizable compound having an allophanate group; (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups; (c) a photopolymerization initiator; and Including, A dental photopolymerizable composition for use with a 3D printer, comprising 1 to 25 parts by weight of a (meth)acrylic polymer having one (meth)acryloyloxy group, relative to a total of 100 parts by weight of (a) a (meth)acrylic polymerizable compound having an allophanate group and (b) a (meth)acrylic polymer having one or two (meth)acryloyloxy groups.

2. (a) 30 to 99% by weight of a (meth)acrylic polymerizable compound having an allophanate group, (b) containing 1 to 70% by weight of a (meth)acrylic polymer having one or two (meth)acryloyloxy groups; 2. The dental photopolymerizable composition for 3D printers according to claim 1, comprising 0.01 to 5 parts by weight of (c) a photopolymerization initiator per 100 parts by weight of the total of (a) the (meth)acrylic polymerizable compound having an allophanate group and (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups.

3. 2. The dental photopolymerizable composition for 3D printers according to claim 1, wherein (a) the (meth)acrylic polymerizable compound having an allophanate group has a viscosity of 60,000 mPa·s or less as measured using a rotational rheometer at a temperature of 23°C and a rotation speed of 20 rpm.

4. The dental photopolymerizable composition for 3D printers according to claim 1, wherein (a) the (meth)acrylic polymerizable compound having an allophanate group has a glass transition temperature of a cured product of 120°C or lower.

5. The dental photopolymerizable composition for 3D printers according to claim 1, wherein (a) the (meth)acrylic polymerizable compound having an allophanate group has three or more (meth)acryloyloxy groups.

6. The dental photopolymerizable composition for 3D printers according to claim 1, wherein (b) the (meth)acrylic polymer having one or two (meth)acryloyloxy groups does not contain a urethane structure.

7. (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups includes at least one (meth)acrylic polymer having two (meth)acryloyloxy groups. A dental photopolymerizable composition for 3D printers according to claim 1.

8. (b) The (meth)acrylic polymer having one or two (meth)acryloyloxy groups comprises a (meth)acrylic polymer containing one or more reactive groups selected from the group consisting of hydroxyl groups and carboxylic acid groups. A dental photopolymerizable composition for 3D printers according to claim 1.

9. (c) The dental photopolymerizable composition for 3D printers according to claim 1, wherein the photopolymerization initiator is one or more selected from the group consisting of alkylphenone compounds, acetophenone compounds, and acylphosphine oxide compounds.

10. 2. The dental photopolymerizable composition for 3D printers according to claim 1, wherein the viscosity measured by a rotational rheometer under conditions of a temperature of 23°C and a rotation speed of 20 rpm is 10,000 mPa·s or less.

11. The dental photopolymerizable composition for 3D printers according to claim 1, wherein the glass transition point of the cured product is 30 to 100°C.

12. The dental photopolymerizable composition for 3D printers according to claim 1 , further comprising an additive.

13. The dental photopolymerizable composition for 3D printers according to claim 12, wherein the additive comprises one or more selected from the group consisting of a colorant, an ultraviolet absorber, a polymerization inhibitor, and a fluorescent agent.

14. The dental photopolymerizable composition for 3D printers according to claim 12, wherein the additive is contained in an amount of 0.0001 to 2 parts by weight relative to 100 parts by weight of the dental photopolymerizable composition for 3D printers excluding the additive.

15. A dental product produced by a stereolithography 3D printer using the dental photopolymerizable composition for 3D printers according to any one of claims 1 to 14.

16. A dental aligner material produced by a stereolithography 3D printer using the dental photopolymerizable composition for 3D printers according to any one of claims 1 to 14.

17. A denture base material produced by a stereolithography type 3D printer using the dental photopolymerizable composition for 3D printers according to any one of claims 1 to 14.

18. A dental mouthpiece produced by a stereolithography type 3D printer using the dental photopolymerizable composition for 3D printers according to any one of claims 1 to 14.