STEREOLITHOGRAPHIC METHOD AND COMPOSITION

Abstract

The invention concerns a method for producing a three-dimensional object, in particular an artificial tooth, by stereolithography wherein a liquid photocurable resin composition is cured by light. Said photocurable resin composition contains, based on the total weight of the photocurable resin composition, (i) from 90 to 99.9% by weight of a radical polymerizable organic compound (A) selected from radical polymerizable monomers, oligomers, pre-polymers and mixtures thereof; and (ii) from 0.1 to 10% by weight of a photosensitive radical polymerization initiator (B). Said radical polymerizable organic compound (A) comprises, based on the weight of the radical polymerizable organic compound (A), from 0.5 to 20% by weight of a polyrotaxane compound comprising a polymer chain selected from polyethylene glycol (PEG), polypropylene glycol (PPG), polyethylene glycol-polypropylene glycol (PEG-PPG) block copolymer or polydimethylsiloxane (PDMS), onto which the cyclodextrin ring(s) is/are slipped and wherein the cyclodextrin is derivatized with at least a radical polymerizable group. The invention also concerns a relative liquid photocurable resin composition and articles produced thereby.

Claims

1) Method for producing a three-dimensional object by stereolithography wherein a liquid photocurable resin composition is cured by light, said photocurable resin composition containing: (i) from 90 to 99.9% by weight, based on the total weight of the photocurable resin composition, of a radical polymerizable organic compound (A) selected from radical polymerizable monomers, oligomers, pre-polymers and mixtures thereof; (ii) from 0.1 to 10% by weight, based on the total weight of the photocurable resin composition, of a photosensitive radical polymerization initiator (B); wherein said radical polymerizable organic compound (A) comprises, based on the weight of the radical polymerizable organic compound (A), from 0.5 to 20% by weight of a polyrotaxane compound having the following general formula (I): ##STR00003## wherein Z is a bulky capping group, preferably selected from adamantane and its derivatives, 2,4-dinitrophenyl, or cyclodextrin and its derivatives; the dotted line ------ is a polymer chain selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), polyethylene glycol-polypropylene glycol (PEG-PPG) block copolymer or polydimethylsiloxane (PDMS), onto which the cyclodextrin ring(s) is/are slipped; m is an integer and independently represents the number of glucose units in the cyclodextrin ring, preferably m=6, 7 or 8; n is an integer and represents the number of cyclodextrin rings; X is independently H, or a radical polymerizable group, such as a methacryloyl-containing group or an acryloyl-containing group, with the condition that at least one X is a radical polymerizable group.

2) Method according to claim 1, characterized in that it comprises the following steps: (a) accommodating said liquid photocurable resin composition in a shaping container having a light permeable bottom face, and irradiating the photocurable resin composition in the shaping container with light in a predetermined shape pattern through the light permeable bottom face of the shaping container in accordance with slice data, every one layer based on three-dimensional CAD data to form a cured resin layer having a predetermined shape pattern for one layer; (b) lifting up the cured resin layer for one layer formed during step (a), thereby allowing the liquid photocurable resin composition to flow into the space between the lower face of the cured resin layer and the bottom face of the shaping container, and irradiating the photocurable resin composition between the lower face of the cured resin layer and the bottom face of the shaping container with light in a predetermined shape pattern through the light permeable bottom face of the shaping container in accordance with slice data, every one layer based on three-dimensional CAD data to form a further cured resin layer having a predetermined shape pattern for one layer, and (c) repeating the operation of step (b) until the desired object is obtained.

3) The method according to claim 2, characterized in that the three-dimensional CAD data are obtained using a computed tomography device (CT device), a magnetic resonance imaging device (MRI), a computed radiographic device (CR device), or an intraoral 3D scanner.

4) Method according to claim 1, characterized in that the radical polymerizable group of said liquid photocurable resin composition is constituted by a methacryloyl or acryloyl-containing unit bonded by a spacer unit to said cyclodextrin ring.

5) Liquid photocurable resin composition for stereolithography, containing: (i) from 90 to 99.9% by weight, based on the total weight of the photocurable resin composition, of a radical polymerizable organic compound (A) selected from radical polymerizable monomers, oligomers, pre-polymers and mixtures thereof; (ii) from 0.1 to 10% by weight, based on the total weight of the photocurable resin composition, of a photosensitive radical polymerization initiator (B); wherein said radical polymerizable organic compound (A) comprises, based on the weight of the radical polymerizable organic compound (A), from 0.5 to 20% by weight of a polyrotaxane compound having the following general formula (I): ##STR00004## wherein Z is a bulky capping group, preferably selected from adamantane and its derivatives, 2,4-dinitrophenyl, or cyclodextrin and its derivatives; the dotted line ------ is a polymer chain selected from the group consisting of polyethylene glycol (PEG), polypropylene glycol (PPG), polyethylene glycol-polypropylene glycol (PEG-PPG) block copolymer or polydimethylsiloxane (PDMS), onto which the cyclodextrin ring(s) is/are slipped; m is an integer and independently represents the number of glucose units in the cyclodextrin ring, preferably m=6, 7 or 8; n is an integer and represents the number of cyclodextrin rings; X is independently H, or a radical polymerizable group, such as a methacryloyl-containing group or an acryloyl-containing group, with the condition that at least one X is a radical polymerizable group.

6) The liquid photocurable resin composition according to claim 5, characterized in that said radical polymerizable group is constituted by a methacryloyl or acryloyl-containing unit bonded by a spacer unit to said cyclodextrin ring.

7) The liquid photocurable resin composition according to claim 6, characterized in that said radical polymerizable group is independently selected from
—[(C═O)(CH.sub.2).sub.5O—].sub.p—CONH(CH.sub.2).sub.2CO.sub.2C(R.sup.1)═CH.sub.2 or
—CH.sub.2CHMeO—[(C═O)(CH.sub.2).sub.5O—].sub.q—CONH(CH.sub.2).sub.2CO.sub.2C(R.sup.1)═CH.sub.2, wherein R.sup.1 represents a hydrogen atom or a methyl group with p and q being integers indicating the number of repeating units.

8) The liquid photocurable resin composition according to claim 5, characterized in that said radical polymerizable organic compound (A) further comprises: (i) a urethane-based di(meth)acrylate compound (A-1a) obtained by the reaction of 1 mol of an organic diisocyanate compound with 2 mol of hydroxyalkyl (meth)acrylate, represented by the following general formula (A-1a):
D-{NH—CO—O—R.sup.2—O—CO—C(R.sup.1)═CH.sub.2}.sub.2  (A-1a) wherein R.sup.1 represents a hydrogen atom or a methyl group, R.sup.2 represents an alkylene group, and D represents an organic diisocyanate compound residue; and/or (ii) a di(meth)acrylate compound (A-1b) obtained by the reaction of 1 mol of a diepoxy compound with 2 mol of (meth)acrylic acid, represented by the following general formula (A-1b):
E-{C(H)(OH)—CH.sub.2—O—CO—C(R.sup.3)═CH.sub.2}.sub.2  (A-1b) wherein R.sup.3 represents a hydrogen atom or a methyl group, and E represents a diepoxy compound residue.

9) The liquid photocurable resin composition according to claim 5, characterized in that the viscosity of said photocurable resin composition is 20,000 mPa.Math.s or less, more preferably 15,000 mPa.Math.s or less, and still more preferably 10,000 mPa.Math.s or less, when measured at 25° C. according to method ISO 2555 with a single cylinder rotational viscometer.

10) The liquid photocurable resin composition according to claim 5, characterized in that every radical polymerizable organic compound (A) is a methacrylate-based compound.

11) The liquid photocurable resin composition according to claim 5, characterized in that in said polyrotaxane compound the polymer chain is polyethylene glycol, the cyclodextrin is α-cyclodextrin and the bulky groups are —NH-adamantane.

12) The liquid photocurable resin composition according to claim 5, characterized in that said radical polymerizable organic compound (A) further includes a viscosity reducing compound (A-2) which is at least one of a methacrylic acid ester, an acrylic acid ester, a polyester methacrylate, a polyester acrylate, a polyether methacrylate of alcohols, a polyether acrylate of alcohols.

13) The liquid photocurable resin composition according to claim 5, characterized in that said radical polymerizable organic compound (A) other than the polyrotaxane compound and other than compounds (A-1a), (A-1b) and (A-2) is selected from radical polymerizable monomers.

14) The liquid photocurable resin composition according to claim 5, characterized in that said photocurable resin composition is blended with 10 to 250 parts per weight of a filler (C) per every 100 parts per weight of said photocurable resin composition.

15) The liquid photocurable resin composition according to claim 5, characterized in that said filler (C) is selected from a silica powder, an alumina powder, a zirconia powder, a glass powder, powders prepared by treating the above powders with a coupling agent, and mixtures thereof.

16) A three-dimensional article comprising a photo-cured resin composition obtained by the method according to claim 1.

17) The three-dimensional article according to claim 16, characterized in that said three-dimensional article is an artificial tooth.

Description

DESCRIPTION OF PREFERRED EXAMPLE EMBODIMENTS OF THE INVENTION

[0109] In the present invention, a liquid photocurable resin composition containing a radical polymerizable organic compound (A) which contains a polyrotaxane compound with a photo-polymerizable group and a photosensitive radical polymerization initiator (B) and preferably a filler (C) is used as the material for the production of a three-dimensional object with high toughness and high elasticity.

[0110] A (meth)acryl modified polyrotaxane according to the invention can be derived from a polyrotaxane compound containing cyclodextrin or hydroxypropylized cyclodextrin rings wherein one or more hydroxyl groups of the cyclodextrin ring and/or the hydroxyl group of hydroxypropyl are derivatized with ε-caprolactone in a first step and then in a second step with CH.sub.2═C(R.sup.1)CO.sub.2(CH.sub.2).sub.2NCO wherein R.sup.1 represents a hydrogen atom or a methyl group. More specifically, the polyrotaxane compound can be obtained using the methods disclosed in document JP 2011-046917, those derived from the reaction of hydroxyalkyl polyrotaxane and 2-acryloyloxyethyl isocyanate and the like.

[0111] In particular, as (meth)acryl modified polyrotaxane compound in this sense, various molecular weight compounds are commercially available from Advanced Softmaterials Inc., such as SM3405P, SM2400P, SM1315P, SA3405P, SA2405P and SA1315P which contain solvent.

[0112] There are other products without solvent but with low molecular weight light cross-linking monomer in order to adjust the reactivity or viscosity, such as SM3400C, SA3400C, SA2400C, SA1310C, SM2400C, SM1310C, etc.

[0113] Among these, SM type is a methacryl modified type and SA type is an acryl modified product. The molecular weights of these modified polyrotaxane are: 34 series are about 35,000, 24 series are about 20,000, 13 series are about 11,000. These molecular weights are determined by the ring number of compounds such as cyclodextrins and the length of the straight-chain polymer. Here, an example of Advanced Softmaterials Inc. is shown but the object of the present invention can be achieved also by other polymerizable derivatives of polyrotaxane in the sense of the invention.

[0114] The present invention will be specifically described below by way of Examples, but the present invention is not limited to the following Examples.

Example 1

[0115] (1) 10.0 g of a mixture of cross-linkable oligomer and methacryl modified polyrotaxane (“SeRM Key Mixture SM1310C” manufactured by Advanced Softmaterials Inc.), 80.0 g of urethane dimethacrylate (“U-2TH”, manufactured by Shin Nakamura Chemical Co., Ltd.) obtained by the reaction of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate, which is represented by the formula “CH.sub.2═C(CH.sub.3)—CO—O—CH.sub.2CH.sub.2—O—CO—NH—[CH.sub.2C(CH.sub.3).sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2]—NH—CO—O—CH.sub.2CH.sub.2—O—CO—(CH.sub.3)C═CH.sub.2”, 20 g of triethylene glycol dimethacrylate (“NK-3G”, manufactured by Shin Nakamura Chemical Co., Ltd.), and 1.1 g of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO”, photosensitive radical polymerization initiator, manufactured by BASF Corporation) were mixed, followed by stirring to prepare a liquid photocurable resin composition. Using a B type viscometer (“DV-E”, manufactured by Brookfield Engineering Laboratories, Inc.), the viscosity of the thus obtained photocurable resin composition was measured at 25° C. The result was of 1,200 mPa.Math.s. [0116] (2) Using the liquid photocurable resin composition obtained in the above (1), optical shaping was performed by a regulated liquid surface stereolithography device of a type in which light is irradiated from the bottom side through the light permeable bottom face of a shaping container using a line drawing system (“DigitalWax 029D”, manufactured by DWS SRL) under the conditions of a laser output of 30 mW, a wavelength of 405 nm, a beam diameter of 0.02 mm, a laser operation rate of 4,600 mm/sec, and a one layer thickness of 0.05 mm in accordance with slice data, every one layer based on three-dimensional CAD data, relating to a bar in accordance with ISO 180 and then the impact strength property was measured in accordance with ISO 180 using a measuring device manufactured by Galdabini (Impact 150). [0117] (3) Using the liquid photocurable resin composition obtained in the above (1), dumbbells and bars for the measurement of tensile property and bending property were produced by the regulated liquid surface stereolithography device (DigitalWax 029D) used in the above (2) under the same conditions as in the above (2) in accordance with ISO 527-2 and ISO 178, and then tensile property and bending property were measured in accordance with ISO 527-2 and ISO 178 using a measuring device manufactured by Shimadzu Corporation (AutoGraph AG-XPlus).

[0118] Using ASKER, Model D, manufactured by KOBUNSHI KEIKI CO., LTD., surface hardness was measured as Shore D hardness.

[0119] The results are shown in Table 1 below.

Example 2

[0120] (1) 20.0 g of mixture of cross-linkable oligomer and methacryl modified polyrotaxane (“SeRM Key Mixture SM1310C” manufactured by Advanced Softmaterials Inc.), 80.0 g of urethane dimethacrylate (“U-2TH”, manufactured by Shin Nakamura Chemical Co., Ltd.) obtained by the reaction of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate, which is represented by the formula “CH.sub.2═C(CH.sub.3)—CO—O—CH.sub.2CH.sub.2—O—CO—NH—[CH.sub.2C(CH.sub.3).sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2]—NH—CO—O—CH.sub.2CH.sub.2—O—CO—(CH.sub.3)C═CH.sub.2”, 20 g of triethylene glycol dimethacrylate (“NK-3G”, manufactured by Shin Nakamura Chemical Co., Ltd.), and 1.2 g of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO”, photosensitive radical polymerization initiator, manufactured by BASF Corporation) were mixed, followed by stirring to prepare a liquid photocurable resin composition. Using a B type viscometer (“DV-E”, manufactured by Brookfield Engineering Laboratories, Inc.), the viscosity of the thus obtained photocurable resin composition was measured at 25° C. The result was of 1,740 mPa.Math.s. [0121] (2) Using the liquid photocurable resin composition obtained in the above (1), three-dimensional objects were produced in the same manner as in Example 1, (2) and (3), and then various physical properties were determined in the same manner as in Example 1, (2) and (3), to obtain the results as shown in the following Table 1.

Example 3

[0122] (1) 10.0 g of mixture of cross-linkable oligomer and methacryl modified polyrotaxane (“SeRM Key Mixture SM1310C” manufactured by Advanced Softmaterials Inc.), 80.0 g of urethane dimethacrylate (“U-2TH”, manufactured by Shin Nakamura Chemical Co., Ltd.) obtained by the reaction of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate, which is represented by the formula “CH.sub.2═C(CH.sub.3)—CO—O—CH.sub.2CH.sub.2—O—CO—NH—[CH.sub.2C(CH.sub.3).sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2]—NH—CO—O—CH.sub.2CH.sub.2—O—CO—(CH.sub.3)C═CH.sub.2”, 20 g of triethylene glycol dimethacrylate (“NK-3G”, manufactured by Shin Nakamura Chemical Co., Ltd.), and 1.1 g of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO”, photosensitive radical polymerization initiator, manufactured by BASF Corporation) were mixed, followed by stirring to prepare a liquid photocurable resin, and then the mixture was mixed with 60.0 g of a methacrylsilane-treated silica powder (“Admafine SO-C1”, average particle diameter of 0.25 μm, manufactured by Admatechs Company Limited) to prepare a liquid photocurable resin composition.

[0123] Using a B type viscometer (“DV-E”, manufactured by Brookfield Engineering Laboratories, Inc.), the viscosity of the thus obtained photocurable resin composition was measured at 25° C. The result was of 2,560 mPa.Math.s. [0124] (2) Using the liquid photocurable resin composition obtained in the above (1), optical shaping was performed by the same regulated liquid surface stereolithography device used in Example 1, (2) under the same conditions as in Example 1, (2) to produce an artificial tooth for three true teeth (height of 13.1 mm) over 35 minutes. [0125] (3) After removing a supporting member from the artificial tooth obtained in the above (2) and washing with ethanol, and further post exposing for 20 minutes using a post exposure device (post exposure device “UV curing unit S2”, manufactured by DWS SRL), a surface was simply ground and polished to produce an artificial tooth, and this artificial tooth was used for the patient as a provisional tooth. [0126] (4) Using the liquid photocurable resin composition obtained in the above (1), dumbbells and bars for the measurement of tensile property and bending property were produced by the regulated liquid surface stereolithography device (DigitalWax 029D) used in the above (2) under the same conditions as in the above (2) in accordance with ISO 527-2 and ISO 178, and then tensile property and bending property were measured in accordance with ISO 527-2 and ISO 178 using a measuring device manufactured by Shimadzu Corporation (AutoGraph AG-XPlus).

[0127] In the same manner also the bars in accordance with ISO 180 were produced and then the impact strength property was measured in accordance with ISO 180 using a measuring device manufactured by Galdabini (Impact 150).

[0128] Using ASKER, Model D, manufactured by KOBUNSHI KEIKI CO., LTD., surface hardness was measured as Shore D hardness.

[0129] The results are shown in Table 1 below.

Example 4

[0130] (1) 20.0 g of mixture of cross-linkable oligomer and methacryl modified polyrotaxane (“SeRM Key Mixture SM1310C” manufactured by Advanced Softmaterials Inc.), 80.0 g of urethane dimethacrylate (“U-2TH”, manufactured by Shin Nakamura Chemical Co., Ltd.) obtained by the reaction of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate, which is represented by the formula “CH.sub.2═C(CH.sub.3)—CO—O—CH.sub.2CH.sub.2—O—CO—NH—[CH.sub.2C(CH.sub.3).sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2]—NH—CO—O—CH.sub.2CH.sub.2—O—CO—(CH.sub.3)C═CH.sub.2”, 20 g of triethylene glycol dimethacrylate (“NK-3G”, manufactured by Shin Nakamura Chemical Co., Ltd.), and 1.2 g of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO”, photosensitive radical polymerization initiator, manufactured by BASF Corporation) were mixed, followed by stirring to prepare a liquid photocurable resin, and then the mixture was mixed with 60.0 g of a methacrylsilane-treated silica powder (“Admafine SO-C1”, average particle diameter of 0.25 μm, manufactured by Admatechs Company Limited) to prepare a liquid photocurable resin composition.

[0131] Using a B type viscometer (“DV-E”, manufactured by Brookfield Engineering Laboratories, Inc.), the viscosity of the thus obtained photocurable resin composition was measured at 25° C. The result was of 7,620 mPa.Math.s. [0132] (2) Using the liquid photocurable resin composition obtained in the above (1), optical shaping was performed by the same regulated liquid surface stereolithography device used in Example 1, (2) under the same conditions as in Example 1, (2) to produce an artificial tooth for three true teeth (height of 13.1 mm) over 35 minutes. [0133] (3) After removing a supporting member from the artificial tooth obtained in the above (2) and washing with ethanol, and further post exposing for 20 minutes using a post exposure device (post exposure device “UV curing unit S2”, manufactured by DWS SRL), a surface was simply ground and polished to produce an artificial tooth, and this artificial tooth was used for the patient as a provisional tooth. [0134] (4) Using the liquid photocurable resin composition obtained in the above (1), dumbbells and bars for the measurement of tensile property and bending property were produced by the regulated liquid surface stereolithography device (DigitalWax 029D) used in the above (2) under the same conditions as in the above (2) in accordance with ISO 527-2 and ISO 178, and then tensile property and bending property were measured in accordance with ISO 527-2 and ISO 178 using a measuring device manufactured by Shimadzu Corporation (AutoGraph AG-XPlus).

[0135] In the same manner also the bar in accordance with ISO 180 was produced and then the impact strength property was measured in accordance with ISO 180 using a measuring device manufactured by Galdabini (Impact 150). Using ASKER, Model D, manufactured by KOBUNSHI KEIKI CO., LTD., surface hardness was measured as Shore D hardness.

[0136] The results are shown in Table 1 below.

Comparative Example 1

[0137] (1) 80.0 g of urethane dimethacrylate (“U-2TH”, manufactured by Shin Nakamura Chemical Co., Ltd.) obtained by the reaction of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate, which is represented by the formula “CH.sub.2═C(CH.sub.3)—CO—O—CH.sub.2CH.sub.2—O—CO—NH—[CH.sub.2C(CH.sub.3).sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2]—NH—CO—O—CH.sub.2CH.sub.2—O—CO—(CH.sub.3)C═CH.sub.2”, 20 g of triethylene glycol dimethacrylate (“NK-3G”, manufactured by Shin Nakamura Chemical Co., Ltd.), and 1.0 g of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO”, photosensitive radical polymerization initiator, manufactured by BASF Corporation) were mixed, followed by stirring to prepare a liquid photocurable resin composition. Using a B type viscometer (“DV-E”, manufactured by Brookfield Engineering Laboratories, Inc.), the viscosity of the thus obtained photocurable resin composition was measured at 25° C. The result was of 750 mPa.Math.s. [0138] (2) Using the liquid photocurable resin composition obtained in the above (1), three-dimensional objects were produced in the same manner as in Example 1, (2) and (3), and then various physical properties were determined in the same manner as in Example 1, (2) and (3), to obtain the results as shown in the following Table 1.

Comparative Example 2

[0139] (1) 80.0 g of urethane dimethacrylate (“U-2TH”, manufactured by Shin Nakamura Chemical Co., Ltd.) obtained by the reaction of 1 mol of 2,2,4-trimethylhexamethylene diisocyanate with 2 mol of 2-hydroxyethyl methacrylate, which is represented by the formula “CH.sub.2═C(CH.sub.3)—CO—O—CH.sub.2CH.sub.2—O—CO—NH—[CH.sub.2C(CH.sub.3).sub.2CH.sub.2CH(CH.sub.3)CH.sub.2CH.sub.2]—NH—CO—O—CH.sub.2CH.sub.2—O—CO—(CH.sub.3)C═CH.sub.2”, 20 g of triethylene glycol dimethacrylate (“NK-3G”, manufactured by Shin Nakamura Chemical Co., Ltd.), and 1.0 g of 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (“Irgacure TPO”, photosensitive radical polymerization initiator, manufactured by BASF Corporation) were mixed, followed by stirring to prepare a liquid photocurable resin, and then the mixture was mixed with 60.0 g of a methacrylsilane-treated silica powder (“Admafine SO-C1”, average particle diameter of 0.25 μm, manufactured by Admatechs Company Limited) to prepare a liquid photocurable resin composition.

[0140] Using a B type viscometer (“DV-E”, manufactured by Brookfield Engineering Laboratories, Inc.), the viscosity of the thus obtained photocurable resin composition was measured at 25° C. The result was of 1,360 mPa.Math.s. [0141] (2) Using the liquid photocurable resin composition obtained in the above (1), three-dimensional objects were produced in the same manner as in Example 1, (2) and (3), and then various physical properties were determined in the same manner as in Example 1, (2) and (3) to obtain the results as shown in the following Table 1.

TABLE-US-00001 TABLE 1 Example Example Example Example Comparative Comparative Parameter Method 1 2 3 4 Example 1 Example 2 Viscosity of dental photocurable ISO 2555 1200 1740 2560 7620 750 1360 resin composition (mPa .Math. s) (25° C.) Tensile strength (MPa) ISO 527-2-1BA 39.5 32.9 56.1 57.5 34.1 48.5 of cured material Tensile modulus (MPa) ISO 527-2-1BA 1510 1200 3248 3413 1320 3430 of cured material Flexural strength (MPa) ISO 178 67.6 64.8 102 107 63.5 87 of cured material Flexural modulus (MPa) ISO 178 1420 1440 2960 3025 1360 3060 of cured material Surface hardness (Shore D) ISO 868 85 86 92 92 85 92 of cured material Izod impact strength (J/m) ISO 180 136.1 263.9 106 235 82.5 86 of cured material

[0142] As shown by the results indicated in the Table 1 above, the shaped objects obtained in the Examples 1 to 4 can be effectively used as artificial teeth or prototypes thanks to their sufficient surface hardness, tensile strength, tensile modulus, flexural modulus and flexural strength, as well as to their high toughness.

[0143] A practical artificial tooth cannot be produced in a short optical shaping time when the artificial tooth is produced by irradiating the upper surface of a dental photocurable resin composition with light in accordance with an optical shaping method which has most widely been employed heretofore.

[0144] The invention has a wide industrial applicability. According to a method of the present invention for producing a three-dimensional object and using the resin composition according to the invention, it is possible to produce a three-dimensional object, for example an artificial tooth, which is excellent in aesthetic property, hardness, strength, functionality, fitness, and the like in a short time, simply and smoothly, without requiring skill.

[0145] Upon implementation, the method, the photocurable resin composition and the three-dimensional article that are the subjects of the invention can be subjected to further modifications and variant embodiments can be obtained that are not described herein. Said modifications or variants must all be considered protected by the present patent, provided that they fall within the scope of the claims expressed below.