CURABLE RESIN COMPOSITION AND CURED PRODUCT THEREOF, AND METHOD FOR PRODUCING THREE-DIMENSIONAL SHAPED PRODUCT

Abstract

To provide a low-viscosity curable resin composition capable of obtaining a cured product excellent in impact resistance. The curable resin composition contains core-shell type rubber particles, a radically polymerizable compound having one or more radically polymerizable functional groups in the molecule, and a radical polymerization initiator, and the core-shell type rubber particles have a core layer and a shell layer containing a polymer having an alicyclic hydrocarbon group in a side chain, and the radically polymerizable compound contains a radically polymerizable compound having a molecular weight of 500 or more in a ratio of 2 mass % to 70 mass %.

Claims

1. A curable resin composition comprising a core-shell type rubber particle; a radically polymerizable compound having one or more radically polymerizable functional groups in the molecule; a radical polymerization initiator, wherein the core-shell type rubber particle has a core layer and a shell layer containing a polymer having an alicyclic hydrocarbon group in a side chain, and wherein the curable resin composition contains a radically polymerizable compound having a molecular weight of 500 or more in a ratio of 2 mass % or more and 70 mass % or less.

2. The curable resin composition according to claim 1, wherein the radically polymerizable compound contains less than 50 mass % of a (meth) acrylate compound having an alicyclic hydrocarbon group.

3. The curable resin composition according to claim 1, wherein the radically polymerizable compound having a molecular weight of 500 or more is a polyfunctional urethane (meth)acrylate having at least 2 (meth)acryloyl groups and at least 2 urethane groups.

4. The curable resin composition according to claim 1, wherein a content of the core-shell type rubber particle is 7 parts by mass or more and 65 parts by mass or less based on 100 parts by mass of the radically polymerizable compound.

5. The curable resin composition according to claim 1, wherein the core-shell type rubber particle has an average particle size of 0.02 μm to 5 μm.

6. The curable resin composition according to claim 1, wherein the core layer of the core-shell type rubber particle contains at least one kind selected from butadiene rubber, crosslinked butadiene rubber, styrene/butadiene copolymer rubber, acrylic rubber, silicone/acrylic composite rubber, and urethane rubber.

7. The curable resin composition according to claim 1, wherein a mass ratio of the core layer of the core-shell type rubber particle is 1 to 200 parts by mass with respect to 100 parts by mass of the core layer of the core-shell type rubber particle.

8. The curable resin composition according to claim 1, wherein the radically polymerizable compound having a molecular weight of 500 or more contains at least a polyether structure or a polyester structure.

9. A cured product obtained by curing the curable resin composition according to claim 1.

10. A method for producing a three-dimensional shaped product, which comprises a step of forming a shaped product by photocuring a curable resin composition for each layer based on slice data, wherein: the curable resin composition is the curable resin composition according to claim 1.

11. The method according to claim 10, further comprising a step of subjecting the shaped product to heat treatment to obtain a three-dimensional shaped product.

Description

EXAMPLE

[0089] Hereinafter, the present disclosure will be described in detail with reference to examples, but the present disclosure is not limited to these examples.

[0090] <Material s>

[0091] Materials used in the Examples and Comparative Examples are listed below.

[0092] [Radically Polymerizable Compound]

[0093] B-1: Bifunctional urethane acrylate (product name: KAYARAD UX-6101, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight (actual measurement): 6.7×10.sup.3)

[0094] B-2: Bifunctional urethane acrylate (product name: KAYARAD UX-8101, manufactured by Nippon Kayaku Co., Ltd., weight average molecular weight (actual measurement): 3.3×10.sup.3)

[0095] B-3: Acryloyl morpholine (product name: ACMO, manufactured by KJ Chemicals)

[0096] B-4: N-phenylmaleimide (product name: Imirex-P, manufactured by Nippon Shokubai)

[0097] B-5: Isobornyl methacrylate

[0098] B-6: Isobornyl acrylate

[0099] B-7: N-vinyl-ε-caprolactam

[0100] B-8: Polycarbonate diol diacrylate (trade name: UM-90 (1/3) DM, manufactured by Ube Industries, Ltd., molecular weight: approximately 900)

[0101] In B-1 to B-8, B-1, B-2, and B-8 are radically polymerizable compounds having a molecular weight of 500 or more, B-5 and B-6 are (meth) acrylate based compounds having an alicyclic hydrocarbon group, and B-3, B-4, and B-7 are other radically polymerizable compounds.

[0102] [Radical Polymerization Initiator]

[0103] C-1: Photoradical generator (product name: Irgacure 819, made by BASF)

[0104] <Evaluation and Measurement Methods>

[0105] [Average Particle Size of Core-Shell Type Rubber Particles]

[0106] Using a particle size distribution meter (Zetasizer Nano ZS manufactured by Malvern), approximately 1 ml of an acetone dispersion of core-shell type rubber particles was placed in a glass cell, and the arithmetic average particle size was measured at 25° C.

[0107] [Ratio of Compound with Molecular Weight of 500 or More in Radically Polymerizable Compound]

[0108] Gel Permeation Chromatography (GPC) apparatus (Tosoh's HLC-8220 GPC) was equipped with two Shodex GPC LF-804 columns (manufactured by Showa Denko K.K., Limit of elimination molecular weight: 2×10.sup.6, Separation range: 300 to 2×10.sup.6) in series, and THF was used as a developing solvent at 40° C., and a molecular weight distribution (retention time - detection intensity curve) was obtained by an RI (Refractive Index, Differential Refractive Index) detector. The molecular weight distribution was divided by the retention time corresponding to the molecular weight of 500 derived from the calibration curve in terms of standard polystyrene, and the ratio (Y/X×100 [%]) of the area (Y) having the molecular weight of 500 or more to the total area (X) was calculated to obtain the compound ratio having the molecular weight of 500 or more.

[0109] [Charpy Impact Strength]

[0110] According to JIS K 7111, a notch with a depth of 2 mm and a depth of 45° was formed in the center of the specimen by a notch forming machine (product name: Notching Tool A-4, manufactured by Toyo Seiki). Using an impact testing machine (product name: IMPACT TESTER IT, manufactured by Toyo Seiki), the specimen was fractured at an energy of 2J from the back of the notch. The energy required for the fracture was calculated from the angle to which a hammer, which had been swung up to 150°, swung up after the fracture of the test piece, and it was used as the Charpy impact strength and an index of impact resistance.

[0111] [Viscosity of Curable Resin Composition]

[0112] Viscosity was measured by the rotary rheometer method. Concretely, the measurement was performed as follows using a viscoelastic measuring device (trade name: Physica MCR 302, manufactured by Anton Paar).

[0113] About 0.5 mL of the sample was filled to a measuring instrument equipped with a cone-plate type measuring jig (product name: CP 25-2, manufactured by Anton Paar; 25 mm diameter 2° with, and adjust the temperature to 25° C. The measurement was performed at a constant shear rate of 5s.sup.1 with a data interval of 6 seconds and the value at 120 seconds was defined to be the viscosity.

[0114] <Production of Acetone Dispersion of Core-Shell Type Rubber Particles>

Production Example 1

[0115] 185 parts by mass of polybutadiene latex (product name: Nipol LX 111 A2, manufactured by Nippon Zeon) (corresponding to 100 parts by mass of polybutadiene rubber particles) and 315 parts by mass of deionized water were charged into a 1 L glass container, and the mixture was stirred at 60° C. while performing nitrogen substitution. Then, 0.005 parts by mass of disodium ethylenediaminetetraacetate (EDTA), 0.001 parts by mass of ferrous sulfate-7 hydrate and 0.2 parts by mass of sodium formaldehyde sulfoxylate were added to prepare polybutadiene rubber particles as the core layer. Thereafter, by continuously adding a mixture of 35 parts by mass of the radically polymerizable compound forming the shell layer (17.5 parts by mass of methyl methacrylate (MMA) and 17.5 parts by mass of isobornyl methacrylate (IBMA)) and 0.1 parts by mass of cumene hydroperoxide over 2 hours, the radically polymerizable compound was graft-polymerized on the surface of the polybutadiene rubber particles. After the addition was completed, the reaction was further stirred for 2 hours to obtain an aqueous dispersion of core-shell type rubber particles each having a polybutadiene rubber as a core layer and a copolymer of MMA and IBMA as a shell layer.

[0116] The aqueous dispersion of the core-shell type rubber particles obtained as described above was charged into 450 parts by mass of acetone and mixed uniformly. The supernatant was removed after centrifugation at 12000 rpm for 30 minutes at 10° C. using a centrifuge. An acetone dispersion of the core-shell type rubber particles A-1 was obtained by adding acetone to the sedimented core-shell type rubber particles, redispersing them, centrifuging them under the same conditions as described above, and removing the supernatant liquid twice. The average particle size of the core-shell type rubber particles A-1 was 0.25 μm.

Production Examples 2 to 5

[0117] An acetone dispersion of core-shell type rubber particles was obtained in the same manner as in Production Example 1 except that the composition of the radically polymerizable compound forming the shell layer was changed as shown in Table 1. The respective average particle size of the core-shell type rubber particles was as shown in Table 1.

Production Example 6

[0118] 185 parts by mass of polybutadiene latex (product name: Nipol LX 111 A2, manufactured by Nippon Zeon) (corresponding to 100 parts by mass of polybutadiene rubber particles) and 300 parts by mass of deionized water were charged into a 1 L glass container, and the mixture was stirred at room temperature while performing nitrogen substitution. Thereafter, a mixture of 35 parts by mass (17.5 parts by mass of methyl methacrylate (MMA) and 17.5 parts by mass of isobornyl methacrylate (IBMA)) of a radically polymerizable compound forming a shell layer and 0.1 parts by mass of cumene hydroperoxide was added at a stretch and the obtained mixture was stirred at room temperature for 2 hours. After heating the stirred mixture at 60° C., an aqueous solution prepared by dissolving 0.005 parts by mass of disodium ethylenediaminetetraacetate (EDTA), 0.001 parts by mass of ferrous sulfate-7 hydrate and 0.2 parts by mass of sodium formaldehyde sulfoxylate in 15 parts by mass of deionized water was added to the stirred mixture to form a shell layer comprising a polymer of a radically polymerizable compound on the surface of polybutadiene rubber particles as a core layer. The reaction was terminated by stirring at 60° C. for 2 hours to obtain an aqueous dispersion of core-shell type rubber particles having a polybutadiene rubber as a core layer and a copolymer of MMA and IBMA as a shell layer.

[0119] An aqueous dispersion of the core-shell type rubber particles obtained as described above was charged into 450 parts by mass of acetone and mixed uniformly. The supernatant was removed after centrifugation at 12000 rpm for 30 minutes at 10° C. using a centrifuge. An acetone dispersion of the core-shell type rubber particles A-4 was obtained by adding acetone to the sedimented core-shell type rubber particles, redispersing them, centrifuging them under the same conditions as described above, and removing the supernatant liquid twice. The average particle size of the core-shell type rubber particles A-4 was 0.26 μm.

TABLE-US-00001 TABLE 1 Production Example 1 2 3 4 5 Rubber particle A-1 A-2 A-3 D-1 D-2 Core layer Polybutadiene rubber particle 100 100 100 100 100 [parts by mass] Shell layer (MMA) 17.5 17.5 17.5 35 17.5 [parts by mass] (IBMA) 17.5 0 0 0 0 (IBA) 0 17.5 0 0 0 (DCPMA) 0 0 17.5 0 0 (St) 0 0 0 0 17.5 Average diameter [μm] 0.25 0.26 0.26 0.25 0.27

Example 1

[0120] An acetone dispersion of the core-shell type rubber particles A-1 (18 parts by mass solid content); B-1 (30 parts by mass) and B-2 (10 parts by mass) as radically polymerizable compounds having a molecular weight of 500 or more; B-3 (50 parts by mass) as other radically polymerizable compounds; B-5 (10 parts by mass) as a metacrylate compound having an alicyclic hydrocarbon group; and C-1 (2 parts by mass) as a radical polymerization initiator were mixed uniformly. The curable resin composition was obtained by removing acetone as a volatile component.

[0121] A cured product was prepared from the prepared curable resin composition by the following method. First, a mold having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was sandwiched between two pieces of quartz glass, and a curable resin composition was poured into the mold. The poured curable resin composition was alternately irradiated with 5 mW/cm.sup.2 of ultraviolet rays from both sides of the mold 4 times for 120 seconds by an ultraviolet irradiation machine (product name: LIGHT SOURCE EXECURE 3000, made by HOYA CANDEO OPTRONICS). The cured product thus obtained was subjected to heat treatment by placing in a heating oven at 50° C. for 1 hour and placing in a heating oven at 100° C. for 2 hours, thus a test piece having a length of 80 mm, a width of 10 mm, and a thickness of 4 mm was obtained.

[0122] Table 2 shows the viscosity of the curable resin compositions and the Charpy impact strength of the cured products.

Examples 2 to 9 and Comparative Examples 1 to 4

[0123] A curable resin composition and a cured product were obtained in the same manner as in Example 1 except that the components shown in Table 2 were used. Table 2 shows the viscosity of the curable resin composition and the Charpy impact strength of the cured product.

Example 10

[0124] A curable resin composition prepared in the same manner as in Example 1 was used and to form a shaped product according to slice data based on a three-dimensional shape of a rectangular parallelepiped having a size of 80 mm×10 mm×4 mm by using a 3D printer (DWS-020X manufactured by DWS Co., Ltd., optical shaping device for regulating liquid level method). The resulting shaped product was irradiated with ultraviolet light using a UV Curing Unit M (manufactured by DWS Co.) for 30 minutes, then placed in a heated oven at 50° C. for 1 hour, then placed in a heated oven at 100° C. for 2 hours to obtain a test piece.

TABLE-US-00002 TABLE 2 Example Comparative Example 1 2 3 4 5 6 7 8 9 10 1 2 3 4 Core-shell A-1 18 18 18 18 18 18 18 type A-2 18 rubber particle A-3 18 [part by mass] A-4 18 11 18 D-1 18 D-2 18 Radical B-1 30 30 30 30 30 30 30 30 20 30 30 30 30 30 polymerizable B-2 10 10 10 10 10 10 compound B-3 50 50 50 70 50 30 30 50 50 50 50 20 (part by B-4 10 10 10 10 10 10 10 mass) B-5 20 50 B-6 40 40 30 60 B-7 40 10 B-8 20 Ratio of radical polymerizable compound 40 40 40 30 30 30 30 30 30 40 40 40 30 30 having 500 or more molecular weight in radical polymerizable compound (% by mass) Ratio of (meth)acrylate compound having 0 0 0 0 20 40 40 30 0 0 0 0 50 60 alicyclic hydrocarbon group in radical polymerizable compound (% by mass) Radical C-1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 initiator (part by mass) Evaluation Charpy impact 10.6 10.6 11.4 12.3 10.3 11.5 8.6 11.7 11.3 11.1 11.5 11.9 4.6 11.7 strength (kJ/m.sup.2) Viscosity 1.8 1.9 2.0 0.8 1.0 1.8 0.8 1.0 1.2 1.8 5.2 8.3 4.7 7.2 (mPa .Math. s)

[0125] According to the present disclosure, it is possible to provide a curable resin composition which can form a cured product excellent in impact resistance, has a low viscosity and is excellent in workability in producing a cured product.

[0126] The present disclosure is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the present disclosure. Accordingly, in order to make the scope of the present disclosure public, the following claims are attached.

[0127] While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.