Polymer composition for stereolithography

Abstract

An object of the present invention is to provide a novel polymer composition for stereolithography that is capable of suitably providing an elastic molded product by stereolithography. A polymer composition for stereolithography containing a liquid polymer and a monomer, the polymer composition for stereolithography having a viscosity of 3,000 mPa.Math.s or less, the viscosity being measured in an environment of a temperature of 25° C. and a relative humidity of 50% using an E-type viscometer under conditions of a cone plate diameter φ of 25 mm and a shear rate of 100 sec.sup.−1.

Claims

1. A polymer composition for stereolithography comprising: a liquid polymer; a monomer; and at least two photopolymerization initiators different in absorption band; wherein the polymer composition for stereolithography has a viscosity of 3,000 mPa.Math.s or less, the viscosity being measured in an environment of a temperature of 25° C. and a relative humidity of 50% using an E-type viscometer under conditions of a cone plate diameter φ of 25 mm and a shear rate of 100 sec.sup.−1, and wherein the liquid polymer includes at least one of a liquid isoprene having a (meth)acryloyl group and a liquid isobutylene having a (meth)acryloyl group.

2. The polymer composition for stereolithography according to claim 1, wherein the liquid polymer includes the liquid isoprene having the (meth)acryloyl group.

3. The polymer composition for stereolithography according to claim 1, wherein the liquid polymer has a number average molecular weight of 5,000 or more and 500,000 or less, wherein the number average molecular weight of the liquid polymer is a value in terms of standard polystyrene, and is measured using a gel permeation chromatograph.

4. The polymer composition for stereolithography according to claim 1, wherein the liquid polymer has a viscosity of 100 mPa.Math.s or more and 1,000,000 mPa.Math.s or less, the viscosity being measured in an environment of a temperature of 25° C. and a relative humidity of 50% using an E-type viscometer under conditions of a cone plate diameter φ of 25 mm and a shear rate of 100 sec.sup.−1.

5. The polymer composition for stereolithography according to claim 1, having a content rate of the liquid polymer of 15 mass % or more and 70 mass % or less.

6. The polymer composition for stereolithography according to claim 1, having a percentage of the monomer of 30 mass % or more and 85 mass % or less based on 100 mass % in total of the liquid polymer and the monomer.

7. The polymer composition for stereolithography according to claim 1, further comprising an oligomer, and having a percentage of the monomer of 30 mass % or more and 90 mass % or less based on 100 mass % in total of the liquid polymer, the monomer, and the oligomer.

8. The polymer composition for stereolithography according to claim 1, further comprising an oligomer, and having a total percentage of the monomer and the oligomer of 30 mass % or more and 90 mass % or less based on 100 mass % in total of the liquid polymer, the monomer, and the oligomer.

9. The polymer composition for stereolithography according to claim 8, wherein the oligomer is at least one of urethane (meth)acrylate and epoxy (meth)acrylate.

10. The polymer composition for stereolithography according to claim 7, wherein the oligomer includes a (meth)acrylate.

11. The polymer composition for stereolithography according to claim 1, wherein the monomer is at least one of monofunctional to tetrafunctional monomers.

12. The polymer composition for stereolithography according to claim 1, wherein the monomer includes a (meth)acrylate.

13. An elastic molded product, which is a cured product of the polymer composition for stereolithography according to claim 1.

14. A method for producing an elastic molded product, the method comprising: supplying the polymer composition for stereolithography according to claim 1 onto a molding table, and curing the polymer composition for stereolithography by light irradiation to form a first layer of a cured product; supplying, onto the first layer of the cured product, the polymer composition for stereolithography for forming a second layer of a cured product, and curing the polymer composition for stereolithography by light irradiation to form the second layer of the cured product; and repeating the step of forming the second layer of the cured product until an N-th layer is formed to produce an elastic molded product having a three-dimensional shape.

Description

EXAMPLES

(1) Hereinafter, examples of the present invention will be described. However, the present invention is not limited to the following examples. Details of materials used in the examples and comparative examples are shown in Table 1.

(2) TABLE-US-00001 TABLE 1 Number average molecular Viscosity weight at 25° C. Material Product name Manufacturer (Mn) mPa .Math. s Liquid Methacryloyl ester compound (98%) of maleic anhy- UC-102M KURARAY CO., LTD. 17,000 60,000 polymer group- dride adduct of isoprene polymer and 2- UC-203M 35,000 400,000 containing hydroxyethyl methacrylate polyisobutylene EP400V KANEKA 90,000 1,000,000 liquid polymer having acryloyl groups or both terminals CORPORATION Monomer Mono- ethoxylated nonylphenol acrylate SR504 ARKEMA K.K. 450 100 functional methyl 2-allyloxymethyl acrylate AOMA NIPPON SHOKUBAI 156 1.6 acrylate CO., LTD. isostearyl acrylate ISTA OSAKA ORGANIC 324 17 CHEMICAL INDUSTRY LTD. m-phenoxybenzyl acrylate LIGHT KYOEISHA 254 15 ACRYLATE CHEMICAL POB-A Co., LTD. dicyclopentanyl acrylate FA-513AS Hitachi Chemical 206 17 Company, Ltd. isobornyl acrylate IBXA OSAKA ORGANIC 208 9 CHEMICAL INDUSTRY LTD. Bifunc- polyethylene glycol diacrylate SR344 ARKEMA K.K. 508 57 tional dipropylene glycol diacrylate SR508 242 10 acrylate propoxylated neopentyl glycol diacrylate SR9003 328 15 Trifunc- propoxylated glyceryl triacrylate SR9020 428 95 tional acrylate Oligomer Urethane aromatic urethane acrylate oligomer CN992 — 5,000 acrylate aliphatic urethane acrylate oligomer CN966 — 60,000 aliphatic urethane acrylate oligomer CN8881 4,000 200,000 polyurethane acrylate/acrylic monomer BEAMSET ARAKAWA — 170,000 505A-6 CHEMICAL INDUSTRIES, LTD. Diluent Liquid BR butadiene polymer compound L-BR302 KURARAY CO., LTD. 5,500 1,200 polymer Photopoly- Alkylphenone 2-hydroxy-2-methylpropiophenone Omnirad BASF SE 164 25 merization (Irgacure) 1173 initiator Acylphosphine Bis(2,4,6-trimethylbenzoyl)phenylphosphine Omnirad 419 — oxide oxide (Irgacure) 819 Monoacylphos- 2,4,6-trimethylbenzoyl-diphenyl phosphine Omnirad 348 — phine oxide oxide (Irgacure) TPO Photo- Thioxanthone 2-isopropylthioxanthone ITX Tokyo Chemical — — sensitizer Industry Co., Ltd. Benzophenone 4,4′-bis(diethylamino)benzophenone EMK: TR-EMK CHANGZHOU TRONLY — — Acridine 9-phenylacridine 9-PA: TR- NEW ELECTRONIC — — PAG-101 MATERIALS CO., LTD. (Changzhou, China) Anthracene 9,10-bis(octanoyloxy)anthracene DBA: Kawasaki Kasei — — ANTHRACURE Chemicals Ltd. UVS-581 UV blocker 2,2′-(2,5-thiophenediyl)bis(5-tert- Mayzo, Inc. Mayzo, Inc. — — butylbenzoxazole) Vulcanized Pulverized SBR compound VR-1 SRI — — rubber vulcanized rubber (particle size: 85 μm) Filler Silica Nipsil VN3 Tosoh Corporation — — Coupling Silane coupling agent Y9936 Momentive Performance — — agent Materials Inc.

Examples 1 to 31 and Comparative Examples 1 to 6

(3) (Production of Polymer Compositions for Stereolithography)

(4) The materials were mixed and defoamed with a planetary centrifugal mixer at each mixing ratio (parts by mass) shown in Tables 2 to 4 to produce a polymer composition for stereolithography. The components were uniformly mixed. In Tables 2 to 4, “−” indicates that the relevant component is not added.

(5) (Viscosity of Polymer Compositions for Stereolithography)

(6) As for each polymer composition for stereolithography obtained in each of the examples and comparative examples, the viscosity was measured in an environment of a temperature of 25° C. (with an error of ±2° C.) and a relative humidity of 50% using an E-type viscometer (MCR301 manufactured by Anton Paar GmbH) under conditions of a cone plate diameter φ of 25 mm and a shear rate of 100 sec.sup.−1. The results are shown in Tables 2 to 4.

(7) (Production of Elastic Molded Products)

(8) Using each polymer composition for stereolithography obtained in each of the examples and comparative examples, elastic molded products were produced by DLP stereolithography. Specifically, using a 3D printer equipped with a light source (UV-LED) having a peak wavelength of 405 nm, elastic molded products were produced under conditions of a temperature of 25° C., a lamination pitch of 0.05 mm, an irradiation time of 20 seconds per layer, and an illuminance of 5.0 mW/cm.sup.2 at the wavelength of 405 nm. In each of the examples and comparative examples, elastic molded products having three types of shapes were produced. The first one is an elastic molded product having a shape of a dumbbell No. 3 test piece according to JIS K6251:2017 used in the tensile test described later, the second one is an elastic molded product having a shape of a compressed ball of a diameter φ of 29×12.5 mm according to JIS K6262:2013 used in the measurement of the hardness and compression set described later, and the third one is an elastic molded product test piece according to JIS K6260:2017 (dimensions: length of 150 mm, width of 25 mm, radius of curvature of central groove of 2.38 mm, and thickness of 6.3 mm) used in the cyclic fatigue test described later.

(9) Note, however, that no elastic molded product was produced from the polymer compositions for stereolithography obtained in Comparative Examples 1 to 6 under the above-mentioned conditions due to high viscosity. Therefore, elastic molded products were obtained by increasing the temperature of the liquid composition to 40 to 80° C. to lower the apparent viscosity, or changing the up-down length of the stage during formation of one layer to about 10 times the normal length to form the layer at a speed of one-tenth the normal speed. When a commercially available 3D printer is used as it is, it is difficult to produce the elastic molded products of Comparative Examples 1 to 6 under such conditions. Even if the elastic molded products can be produced, the productivity is very low. Further, since the upper limit of the temperature control in a commercially available 3D printer is about 30° C., it is difficult to produce the elastic molded products of Comparative Examples 1 to 6 using a commercially available 3D printer.

(10) (Hardness of Elastic Molded Products)

(11) As for the elastic molded products (having a shape of a compressed ball of a diameter φ of 29×12.5 mm according to JIS K6252:2013) obtained in the examples and comparative examples, the Shore A hardness was measured according to the method prescribed in JOS K6253-3:2012. The results are shown in Tables 2 to 4.

(12) (Tensile Test of Elastic Molded Products)

(13) As for the elastic molded products (having a shape of a dumbbell No. 3 test piece according to JIS K6251:2017) obtained in the examples and comparative examples, the tensile strength at break and the tensile elongation at break were measured according to the prescription of JIS K6251:2017. The results are shown in Tables 2 to 4. It is determined that the larger the value of the tensile strength at break is, the higher the strength of the elastic molded product is, and the larger the value of the tensile elongation at break is, the easier the elastic molded product is to be elongated and the better the mechanical properties of the elastic molded product are.

(14) (Compression Set)

(15) The elastic molded products (having a shape of a compressed ball of a diameter φ of 29×12.5 mm according to JIS K6262:2013) obtained in the examples and comparative examples were compressed by 25% at a temperature of 23° C. for 22 hours, the compression was released, and then the compression set was measured after a lapse of 0.5 hours from the above-mentioned process according to the prescription of JIS K6262:2013. The results are shown in Tables 2 to 4. It is determined that the smaller the value of the compression set is, the better the restoring force of the elastic molded product is.

(16) (Cyclic Fatigue Test)

(17) The elastic molded products (test pieces according to JIS K6260:2017 (dimensions: length of 150 mm, width of 25 mm, radius of curvature of central groove of 2.38 mm, and thickness of 6.3 mm)) obtained in the examples and comparative examples were subjected to a cyclic fatigue test using a DeMattia flex tester according to the prescription of JIS K6260:2017. A cut was made in the central groove of the test piece, and the test piece was repeatedly flexed at 5 Hz with a strain of 50% applied to the central groove. The degree of growth of the crack during the flexing was measured. The crack growth (times/mm) is calculated by the following equation. The number of flexes until the crack grew by 1 mm was counted. The results are shown in Tables 2 to 4. It is determined that the larger the value is, the longer it takes for the crack to grow by 1 mm, and the better the result of the cyclic fatigue test (flexural crack growth resistance) is.
Crack growth (times/mm)=number of flexes (times)/length of crack (mm)

(18) (Production Time of Elastic Molded Products)

(19) The time taken for the production of the elastic molded product (molding time for producing a 2-mm-thick sample) was measured. The results are shown in Tables 2 to 4, in which “very good” means a production time of 25 minutes or less, “good” means a production time more than 25 minutes and 60 minutes or less, and “poor” means a production time of 60 minutes or more or that no elastic molded product was produced by DLP stereolithography.

(20) TABLE-US-00002 TABLE 2 Examples 1 2 3 4 5 6 7 8 Polymer Liquid Methac- UC102M 50 15 70 50 50 50 50 50 composi- polymer ryloyl (isoprene tion for group- skeleton) stereoli- containing UC203M — — — — — — — — thography liquid (isoprene polymer skeleton) Monomer Mono- ethoxylated 50 85 30 — — — — — func- nonylphenol tional acrylate acrylate methyl 2- — — — 50 — — — — allyloxymethyl acrylate isostearyl — — — — 50 — — — acrylate m-phenoxybenzyl — — — — — 50 — — acrylate dicyclopentanyl — — — — — — 50 — acrylate isobornyl — — — — — — — 50 acrylate Bifunc- polyethylene — — — — — — — — tional glycol acrylate diacrylate dipropylene — — — — — — — — glycol diacrylate propoxylated — — — — — — — — neopentyl glycol diacrylate Trifunc- propoxylated — — — — — — — — tional glyceryl acrylate triacrylate Oligomer Urethane aromatic — — — — — — — — acrylate urethane acrylate oligomer aliphatic — — — — — — — — urethane acrylate oligomer polyurethane — — — — — — — — acrylate/ acrylic monomer Diluent Liquid BR butadiene — — — — — — — — polymer polymer compound Photo- Alkyl- 2-hydroxy-2- 1.5 1.5 1,5 1.5 1.5 1.5 1.5 1.5 polymer- phenone methyl- ization propiophenone initiator Acylphos- Bis(2,4,6- 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 phine trimethylben- oxide zoyl)phenylphos- phine oxide Mono- 2,4,6- — — — — — — — — acylphos- trimethylben- phine zoyl-diphenyl oxide phosphine oxide Photo- Thio- 2-isopropylthio- — — — — — — — — sensitizer xanthone xanthone Benzo- 4,4′-bis(diethyl- — — — — — — — — phenone amino)benzo- phenone Acridine 9-phenyl- — — — — — — — — acridine Anthra- 9,10-bis(octa- — — — — — — — — cene noyloxy)anthra- cene UV 2,2′-(2,5-thiophene- — — — — — — — — blocker diyl)bis(5-tert-butyl- benzoxazole) Vulcanized Pulverized SBR compound — — — — — — — — rubber vulcanized rubber (particle size: 85 μm) Filler Silica — — — — — — — — Coupling Silane coupling agent — — — — — — — — agent Viscosity mPa × s 1,800 100 3,000 1,200 1,400 1,400 1,400 1,300 at 23° C. Elastic Hardness (Shore A) 53 58 49 62 54 52 65 63 molded Tensile strength at break (MPa) 6.5 7.8 5.8 7.2 6.7 6.3 11.0 10.5 product Tensile elongation at break (%) 140 70 180 110 120 100 110 130 Compression set (%) 3.0 3.5 2.2 3.2 2.9 2.8 3.3 3.2 Cyclic fatigue (crack growth 8,000 500 11,000 6,000 8,000 8,000 6,000 6,000 (times/min)) Production time very very good very very very very very good good good good good good good Examples 9 10 11 12 13 14 15 Polymer Liquid Methac- UC102M 50 50 50 50 50 50 — composi- polymer ryloyl (isoprene tion for group- skeleton) stereoli- containing UC203M — — — — — — 50 thography liquid (isoprene polymer skeleton) Monomer Mono- ethoxylated 30 30 30 40 45 45 50 func- nonylphenol tional acrylate acrylate methyl 2- — — — — — — — allyloxymethyl acrylate isostearyl — — — — — — — acrylate m-phenoxybenzyl — — — — — — — acrylate dicyclopentanyl — — — — — — — acrylate isobornyl — — — — — — — acrylate Bifunc- polyethylene 20 — — — — — — tional glycol acrylate diacrylate dipropylene — 20 — — — — — glycol diacrylate propoxylated — — 20 — — — — neopentyl glycol diacrylate Trifunc- propoxylated — — — 10 — — — tional glyceryl acrylate triacrylate Oligomer Urethane aromatic — — — — 5 — — acrylate urethane acrylate oligomer aliphatic — — — — — 5 — urethane acrylate oligomer polyurethane — — — — — — — acrylate/ acrylic monomer Diluent Liquid BR butadiene — — — — — — — polymer polymer compound Photo- Alkyl- 2-hydroxy-2- 15 1.5 1.5 1.5 1.5 1.5 1.5 polymer- phenone methyl- ization propiophenone initiator Acylphos- Bis(2,4,6- 0.3 0.3 0.3 0.3 0.3 0.3 0.3 phine trimethylben- oxide zoyl)phenylphos- phine oxide Mono- 2,4,6- — — — — — — — acylphos- trimethylben- phine zoyl-diphenyl oxide phosphine oxide Photo- Thio- 2-isopropylthio- — — — — — — — sensitizer xanthone xanthone Benzo- 4,4′-bis(diethyl- — — — — — — — phenone amino)benzo- phenone Acridine 9-phenyl- — — — — — — — acridine Anthra- 9,10-bis(octa- — — — — — — — cene noyloxy)anthra- cene UV 2,2′-(2,5-thiophene- — — — — — — — blocker diyl)bis(5-tert-butyl- benzoxazole) Vulcanized Pulverized SBR compound — — — — — — — rubber vulcanized rubber (particle size: 85 μm) Filler Silica — — — — — — — Coupling Silane coupling agent — — — — — — — agent Viscosity mPa .Math. s 1,500 1,300 1,300 1,800 2,100 2,500 2,300 at 23° C. Elastic Hardness (Shore A) 53 58 54 53 54 52 55 molded Tensile strength at break (MPa) 6.7 9.5 7.3 7.5 7.0 6.3 6.8 product Tensile elongation at break (%) 160 130 120 150 150 170 190 Compression set (%) 3.0 3.3 3.1 3.0 3.1 2.9 2.5 Cyclic fatigue (crack growth 8,000 6,000 8,000 8,000 11,000 11,000 11,000 (times/min)) Production time very very very very very very very good good good good good good good

(21) TABLE-US-00003 TABLE 3 Examples 16 17 18 19 20 21 22 Polymer Liquid Methac- UC102M — 50 50 50 50 50 50 composi- polymer ryloyl (isoprene tion for group- skeleton) stereoli- containing thography liquid polymer Liquid UC203M 50 — — — — — — polymer (isoprene skeleton) Monomer Mono- ethoxylated 50 50 50 50 50 50 50 func- nonylphenol tional acrylate acrylate methyl 2- — — — — — — — allyloxymethyl acrylate isostearyl — — — — — — — acrylate m-phenoxybenzyl — — — — — — — acrylate dicyclopentanyl — — — — — — — acrylate isobornyl — — — — — — — acrylate Bifunc- polyethylene — — — — — — — tional glycol acrylate diacrylate dipropylene — — — — — — — glycol diacrylate propoxylated — — — — — — — neopentyl glycol diacrylate Trifunc- propoxylated — — — — — — — tional glyceryl acrylate triacrylate Oligomer Urethane aromatic — — — — — — — acrylate urethane acrylate oligomer aliphatic — — — — — — — urethane acrylate oligomer polyurethane — — — — — — — acrylate/ acrylic monomer Diluent Liquid BR butadiene 10 — — — — — polymer polymer compound Photo- Alkyl- 2-hydroxy-2- 1.5 1.5 1.5 1.5 1.5 1.5 1.5 polymer- phenone methyl- propiophenone ization Acylphos- Bis(2,4,6- 0.3 — 0.3 0.3 0.3 0.3 0.3 initiator phine trimethylben- oxide zoyl)phenylphos- phine oxide Mono- 2,4,6- — 0.6 — — — — — acylphos- trimethylben- phine zoyl-diphenyl oxide phosphine oxide Photo- Thio- 2-isopropylthio- — — 0.05 — — — — sensitizer xanthone xanthone Benzo- 4,4′-bis(diethyl- — — — 0.05 — — — phenone amino)benzo- phenone Acridine 9-phenyl- — — — — 0.05 — — acridine Anthra- 9,10-bis(octa- — — — — — 0.05 — cene noyloxy)anthra- cene UV 2,2′-(2,5-thiophene- — — — — — — 0.01 blocker diyl)bis(5-tert-butyl- benzoxazole) Vulcanized Pulverized SBR compound — — — — — — — rubber vulcanized rubber (particle size: 85 μm) Filler Silica — — — — — — — Coupling Silane coupling agent — — — — — — — agent Viscosity mPa .Math. s 2,000 1,800 1,800 1,800 1,800 1,800 1,800 at 23° C. Elastic Hardness (Shore A) 53 53 53 53 53 53 53 molded Tensile strength at break (MPa) 6.4 6.3 6.8 6.7 6.6 7.2 6.3 product Tensile elongation at break (%) 170 120 150 140 140 180 140 Compression set (%) 2.3 2.9 2.8 2.9 2.9 2.6 2.9 Cyclic fatigue (crack growth 11,000 8,000 8,000 9,000 8,000 11,000 8,000 (times/min)) Production time very very very very very very very good good good good good good good Examples Comparative Examples 23 24 1 2 3 4 5 6 Polymer Liquid Methac- UC102M 50 5 80 — — — — — composi- polymer ryloyl (isoprene tion for group- skeleton) stereoli- containing thography liquid polymer Liquid UC203M — — — 100 100 100 100 100 polymer (isoprene skeleton) Monomer Mono- ethoxylated 50 95 20 — — — — — func- nonylphenol tional acrylate acrylate methyl 2- — — — — — — — — allyloxymethyl acrylate isostearyl — — — — — — — — acrylate m-phenoxybenzyl — — — — — — — — acrylate dicyclopentanyl — — — — — — — — acrylate isobornyl — — — — — — — 5.0 acrylate Bifunc- polyethylene — — — — — — — — tional glycol acrylate diacrylate dipropylene — — — — — — — — glycol diacrylate propoxylated — — — — — — — — neopentyl glycol diacrylate Trifunc- propoxylated — — — — — — — — tional glyceryl acrylate triacrylate Oligomer Urethane aromatic — — — — — — — — acrylate urethane acrylate oligomer aliphatic — — — — — — — — urethane acrylate oligomer polyurethane — — — — 10 — — — acrylate/ acrylic monomer Diluent Liquid BR butadiene — — — — — — — — polymer polymer compound Photo- Alkyl- 2-hydroxy-2- 1.5 1.5 1.5 3.3 3.0 3.0 3.0 3.0 polymer- phenone methyl- propiophenone ization Acylphos- Bis(2,4,6- 2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 initiator phine trimethylben- oxide zoyl)phenylphos- phine oxide Mono- 2,4,6- — — — — — — — — acylphos- trimethylben- phine zoyl-diphenyl oxide phosphine oxide Photo- Thio- 2-isopropylthio- — — — — — — — — sensitizer xanthone xanthone Benzo- 4,4′-bis(diethyl- — — — — — — — — phenone amino)benzo- phenone Acridine 9-phenyl- — — — — — — — — acridine Anthra- 9,10-bis(octa- — — — — — — — — cene noyloxy)anthra- cene UV 2,2′-(2,5-thiophene- — — — — — — — — blocker diyl)bis(5-tert-butyl- benzoxazole) Vulcanized Pulverized SBR compound — — — 50 — — — — rubber vulcanized rubber (particle size: 85 μm) Filler Silica — — — — — 10 — — Coupling Silane coupling agent — — — — — 0.2 — — agent Viscosity mPa .Math. s 1,850 50 5,500 990,000 300,000 220,000 450,000 80,000 at 23° C. Elastic Hardness (Shore A) 54 64 43 28 32 35 26 36 molded Tensile strength at break (MPa) 7.9 8.3 1.5 1.0 1.3 1.2 0.8 0.8 product Tensile elongation at break (%) 120 30 180 170 130 100 130 80,000 Compression set (%) 2.4 3.8 3.7 1.4 3.7 0.3 1.4 1.2 Cyclic fatigue (crack growth 13,000 100 400 100 400 400 300 100 (times/min)) Production time very very poor poor poor poor poor poor good good

(22) TABLE-US-00004 TABLE 4 Examples 25 26 27 28 29 30 31 Polymer Liquid Methac- UC102M 50 50 20 — — — 25 composi- polymer ryloyl (isoprene tion for group- skeleton) stereoli- containing UC400V — — — 50 50 50 25 thography liquid (isoprene polymer skeleton) Monomer Mono- ethoxylated — — — — — — — functional nonylphenol acrylate acrylate methyl 2- — — — — — — — allyloxymethyl acrylate isostearyl acrylate — — — — — — — m-phenoxybenzyl — — — — — — — acrylate dicyclopentanyl — — — — — — — acrylate isobornyl acrylate 50 30 30 50 30 30 30 Bifunctional polyethylene glycol — — — — — — — acrylate diacrylate dipropylene glycol — — — — — — — diacrylate propoxylated — — — — — — — neopentyl glycol diacrylate Trifunctional propoxylated — — — — — — — acrylate glyceryl triacrylate Oligomer Urethane aromatic urethane — — — — — — — acrylate acrylate oligomer aliphatic urethane — — — — — — — acrylate oligomer polyurethane acrylate/ — — — — — — — acrylic monomer aliphatic urethane — 20 50 — 20 50 20 acrylate oligomer Diluent Liquid BR butadiene polymer — — — — — — — polymer compound Photo- Alkyl- 2-hydroxy-2-methyl- 1.5 1.5 1.5 1.5 1.5 1.5 1.5 polymer- phenone propiophenone ization Acylphos- Bis(2,4,6-trimethylben- 0.7 0.7 0.7 0.7 0.7 0.7 0.7 initiator phine oxide zoyl)phenylphosphine oxide Mono- 2,4,6-trimethylbenzoyl- — — — — — — — acylphos- diphenyl phosphine oxide phine oxide Photo- Thio- 2-isopropylthioxanthone — — — — — — — sensitizer xanthone Benzo- 4,4′-bis(diethyl- — — — — — — — phenone amino)benzo- phenone Acridine 9-phenyl- — — — — — — — acridine Anthra- 9,10-bis(octa- — — — — — — — cene noyloxy)anthra- cene UV 2,2′-(2,5-thiophene- — — — — — — — blocker diyl)bis(5-tert-butyl- benzoxazole) Vulcanized Pulverized SBR compound — — — — — — — rubber vulcanized rubber (particle size: 85 μm) Filler Silica — — — — — — — Coupling Silane coupling agent — — — — — — — agent Viscosity mPa .Math. s 1,300 1,500 2,100 2,100 2,300 2,900 2,100 at 23° C. Elastic Hardness (Shore A) 63 83 79 88 90 85 80 molded Tensile strength at break (MPa) 10.5 11.0 14.0 13.5 15.0 18.0 16.0 product Tensile elongation at break (%) 130 180 250 280 330 370 350 Compression set (%) 3.2 3.8 4.5 8.5 7.2 5.5 5.2 Cyclic fatigue (crack growth (times/min)) 6,000 6,000 4,000 4,000 4,000 6,000 6,000 Production time very very very very very very very good good good good good good good

(23) As shown in Tables 2 to 4, the polymer compositions for stereolithography of Examples 1 to 31 contain a liquid polymer and a monomer, and have a viscosity at a temperature of 25° C. of 3,000 mPa.Math.s or less. The polymer compositions for stereolithography of Examples 1 to 31 have a low viscosity at room temperature, and can be suitably used in stereolithography techniques such as the SLA, the DLP, and the LCD to produce a desired elastic molded product. In addition, the obtained elastic molded products are satisfactory in various physical properties such as the hardness, tensile strength at break, tensile elongation at break, compression set, and cyclic fatigue.