Resin composition and injection-molded article

Abstract

The present invention relates to a resin composition containing: 100 parts by weight of a polypropylene resin; 0.2 parts by weight to 2 parts by weight of an olefinic elastomer; 2 parts by weight to 5 parts by weight of a talc having an aspect ratio in a range of 35 to 60; 2 parts by weight to 5 parts by weight of a fibrous magnesium sulfate having an average fiber diameter of 0.1 μm to 2 μm and an average fiber length of 8 μm to 30 μm; and 0.01 parts by weight to 1 part by weight of a metallic soap that is at least one selected from the group consisting of a magnesium salt of a fatty acid and an aluminum salt of a fatty acid.

Claims

1. A resin composition comprising: a polypropylene resin; an olefinic elastomer; a talc having an aspect ratio in a range of 35 to 60; a fibrous magnesium sulfate having an average fiber diameter of 0.1 μm to 2 μm and an average fiber length of 8 μm to 30 μm; a metallic soap that is at least one selected from the group consisting of a magnesium salt of a fatty acid and an aluminum salt of a fatty acid; and a crystal nucleating agent, wherein the content of the olefinic elastomer is in a range of 0.2 parts by weight to 2 parts by weight per 100 parts by weight of the polypropylene resin, the content of the talc is in a range of 2 parts by weight to 5 parts by weight per 100 parts by weight of the polypropylene resin, the content of the fibrous magnesium sulfate is 2 parts by weight to 5 parts by weight per 100 parts by weight of the polypropylene resin, the content of the metallic soap is in a range of 0.01 parts by weight to 1 part by weight per 100 parts by weight of the polypropylene resin, and the content of the crystal nucleating agent is in a range of 0.005 parts by weight to 1 part by weight per 100 parts by weight of the polypropylene resin.

2. The resin composition according to claim 1, wherein the at least one selected from the group consisting of a magnesium salt of a fatty acid and an aluminum salt of a fatty acid is a salt of a fatty acid containing a polar group.

3. The resin composition according to claim 1, wherein the metallic soap is the magnesium salt of a fatty acid.

4. The resin composition according to claim 1, having an MFR measured under the conditions of 230° C. and 21.2N according to JIS K7210: 2014 being in a range of 15 g/10 min to 60 g/10 min.

5. An injection-molded article, formed of the resin composition described in claim 1.

Description

EXAMPLES

(1) Specific examples according to the present invention will be described below, but it should be understood that the present invention is not construed as being limited to those examples.

(2) Compounding components used in Examples and Comparative Examples below are described.

(3) Polypropylene resin: polypropylene, manufactured by Japan Polypropylene Corporation, item number “NEWCON NBX03GH”, MFR: 23 g/10 min

(4) Olefinic elastomer: ethylene-octene copolymer, manufactured by Dew Chemical, item number “ENGAGE8842”

(5) Talc: talc A (manufactured by Nippon Talc Co., Ltd., item number “PAOG-2”, aspect ratio: 50, average particle diameter: 5 μm), talc B: (manufactured by Nippon Talc Co., Ltd., item number “RA-3”, aspect ratio: 35, average particle diameter: 5 μm), talc C: (manufactured by Nippon Talc Co., Ltd., item number “L-1”, aspect ratio: 20, average particle diameter: 5 μm), talc D: (manufactured by Nippon Talc Co., Ltd., item number “M-3”, aspect ratio: 20, average particle diameter: 10 μm),

(6) Fibrous magnesium sulfate: manufactured by Ube Materials Industries, Ltd., item number “MOS.HIGE”, average fiber length: 8 to 30 μm, average fiber diameter: 0.5 to 1 μm

(7) Metallic soap: magnesium 12-hydroxystearate (manufactured by Nitto Kasei Kogyo K.K., item number: “MS-6”), aluminum 12-hydroxystearate (manufactured by Nitto Kasei Kogyo K.K, item number: “AS-6”), magnesium stearate (manufactured by Nitto Kasei Kogyo K.K., item number: “MS-7”), sodium stearate (manufactured by Nitto Kasei Kogyo K.K., item number: “CS-3”)

(8) Crystal nucleating agent: sodium methylenebis(2,4-di-t-Bu-phenyl)phosphate, manufactured by ADEKA, item number: “ADEKA STAB NA-11”)

Example 1

(9) To 100 parts by weight of the polypropylene resin were mixed 1.1 parts by weight of the polyolefin elastomer, 3.8 parts by weight of talc A, 3.8 parts by weight of the fibrous magnesium sulfate, and 0.043 parts by weight of magnesium 12-hydroxystearate, followed by melt-kneading at 220° C. in a screw revolution speed of 300 rpm by using a twin-screw extrusion kneader, to thereby prepare a resin composition.

(10) The resin composition obtained was molded by using an injection-molding machine to obtain an injection-molded article. Conditions of the injection-molding were temperature: 200° C. and mold temperature: 40° C. Before the molding, the resin composition was dried at 110° C. for 4 hours by using a heating drier.

Examples 2-6 and Comparative Examples 1-6

(11) Resin compositions and corresponding injection-molded articles were obtained in the same manners as in Example 1, except for changing the amount of the polypropylene resin, the amount of the polyolefin elastomer, the kind or mixing amount of the talc, the amount of the fibrous magnesium sulfate, the kind of the metallic soap, and/or the amount of the crystal nucleating agent as shown in Table 1 below.

(12) (Evaluation)

(13) The resin compositions or injection-molded articles obtained in the Examples and Comparative Examples were evaluated as follows. The evaluation results are shown in Table 1 below.

(14) Fluidity (MFR)

(15) Fluidity of the resin compositions obtained in the Examples and Comparative Examples was measured under the conditions of 230° C. and 21.2N according to JIS K7210: 2014.

(16) Flexural Modulus

(17) Flexural modulus of the injection-molded articles obtained in the Examples and Comparative Examples was measured at 23° C. according to JIS K7171: 2016.

(18) Charpy Impact Strength

(19) Charpy impact strength of the injection-molded articles obtained in the Examples and Comparative Examples was measured at 23° C. according to JIS K7111: 2012. Test pieces were notched test pieces.

(20) Specific Gravity

(21) Specific gravity of the resin compositions obtained in the Examples and Comparative Examples was measured according to JIS K7112: 1999.

(22) TABLE-US-00001 TABLE 1 Comp. Comp. Comp. Comp. Comp. Comp. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 1 Ex. 2 Ex. 3 Ex, 4 Ex. 5 Ex. 6 Polypropylene resin 100 100 100 100 100 100 100 100 100 100 100 100 Olefinic elastomer 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.1 1.4 1.1 Talc Talc A 3.8 3.8 3.8 3.8 3.8 3.8 33.8 3.8 3.8 Talc B 3.8 Talc C 3.8 Talc C 3.8 Fibrous magnesium sulfate 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 3.8 Metallic Magnesium 12- 0.043 0.8 0.043 0.043 0.043 0.043 0.054 0.043 1.2 soap hydroxystearate Aluminum 12- 0.043 hydroxystearate Magnesium stearate 0.043 Sodium stearate 0.043 Crystal nucleating agent 0.003 Fluidity (MFR) 45 42 42 49 40 49 40 42 45 25 38 49 Flexural modulus (MPa) 2030 2030 2000 2000 2100 2000 1920 1930 1920 2000 2200 1940 Charpy impact strength (kJ/m.sup.2) 9.7 9.0 9.8 9.6 9.5 9.6 9.5 9.9 9.4 9.5 4.0 9.6 Specific gravity (g/cm.sup.3) 0.94 0.95 0.94 0.94 0.94 0.94 0.94 0.94 0.94 1.05 0.94 0.94

(23) The present invention is not limited to the description of respective embodiments and each of the aspects. The present invention also includes various modifications which can be easily conceived by those skilled in the art without departing from the description of the claims. The contents of publications mentioned in the present specification are incorporated by reference in its entity.

(24) The present application is based on the Japanese Patent Application No. 2019-015609 filed on Jan. 31, 2019, and the entire contents thereof are incorporated herein by reference.