MALEIMIDE COPOLYMER, METHOD FOR PRODUCING SAME, RESIN COMPOSITION AND INJECTION MOLDED BODY

Abstract

A maleimide based copolymer, manufacturing method thereof, and a resin composition using the maleimide based copolymer is provided. The maleimide based copolymer includes 40 to 60 mass % of aromatic vinyl monomer unit, 5 to 20 mass % of vinyl cyanide monomer unit, 35 to 50 mass % of maleimide monomer unit, and 0 to 10 mass % of monomer copolymerizable with these monomer units. The maleimide based copolymer has a glass transition temperature of 165° C. or higher and a melt mass flow rate of 25 to 80 g/10 min measured at 265° C. with 98 N load. By using such maleimide based copolymer, flowability can be improved without decreasing heat resistance providing ability.

Claims

1-8. (canceled)

9. A maleimide based copolymer comprising an aromatic vinyl monomer unit, a vinyl cyanide monomer unit, and a maleimide monomer unit; wherein the maleimide based copolymer has a glass transition temperature of 165 to 200° C.; and a melt mass flow rate of 25 to 80 g/10 min measured in accordance with JIS K 7210 at 265° C. with 98 N load.

10. The maleimide based copolymer of claim 9, comprising 40 to 59.5 mass % of the aromatic vinyl monomer unit, 5 to 20 mass % of the vinyl cyanide monomer unit, and 35 to 50 mass % of the maleimide monomer unit.

11. The maleimide based copolymer of claim 9, further comprising 0.5 to 10 mass % of a dicarboxylic anhydride monomer unit.

12. The maleimide based copolymer of claim 9, wherein a content of residual maleimide monomer is less than 300 ppm.

13. A manufacturing method of the maleimide based copolymer of claim 9, comprising the steps of: an initial polymerizing step to start copolymerization by blending entire amount of vinyl cyanide monomer to be charged, 10 to 90 mass % of aromatic vinyl monomer to be charged, and 0 to 30 mass % of unsaturated dicarboxylic anhydride monomer to be charged; a middle polymerization step to continue copolymerization while adding 50 to 90 mass % of residual amount of the aromatic vinyl monomer and entirety of residual amount of the unsaturated dicarboxylic anhydride monomer, each added by portions or continuously; a final polymerization step to add entirety of residual amount of aromatic vinyl monomer to obtain a copolymer comprising the aromatic vinyl monomer unit, the vinyl cyanide monomer unit, and the dicarboxylic anhydride monomer unit; and imidizing step to imidize the dicarboxylic anhydride monomer unit of the copolymer obtained into the maleimide monomer unit by using ammonia or primary amine.

14. A resin composition comprising 5 to 40 mass % of the maleimide based copolymer of claim 9 and 60 to 95 mass % of one or two or more of a resin selected from the group consisting of acrylonitrile-butadiene-styrene copolymer resin, acrylonitrile-styrene-acryl based rubber copolymer resin, acrylonitrile-ethylene propylene based rubber-styrene copolymer resin, and styrene-acrylonitrile copolymer resin.

15. An injection molded body comprising the resin composition of claim 14.

16. An interior component or an exterior component of an automobile comprising the injection molded body of claim 15.

Description

EXAMPLES AND COMPARATIVE EXAMPLES

Examples 1 to 8, Comparative Examples 1 to 6 (Kneading and Mixing of Maleimide Based Copolymer and ABS Resin)

[0096] The maleimide based copolymers A-1 to A-8, and B-1 to B-6, and commercially available maleimide based copolymer without vinyl cyanide monomer unit “MS-NIP” (available from Denka Company Limited), ABS resin “GR-3000” (available from Denka Company Limited), or ASA resin “Luran S 757G” (available from INEOS Styrolution Group GmbH) were blended by the formulation ratio shown in Table 3 and Table 4. Subsequently, twin screw extruder (TEM-35B, available from Toshiba Machine Co.) was used to extrude the material to obtain pellets. These pellets were used to prepare test pieces using an injection molding machine. Various properties were measured with the test pieces. The results are shown in Table 3 and Table 4.

TABLE-US-00003 TABLE 3 Example 1 2 3 4 5 6 7 8 9 10 maleimide based copolymer used — A-1 A-2 A-3 A-4 A-5 A-6 A-7 A-8 A-1 A-2 evaluation formulation amount GR-3000 mass % 80 80 80 80 80 80 80 80 65 of Luran S 757G mass % 80 property maleimide based mass % 20 20 20 20 20 20 20 20 20 35 copolymer Charpy Impact Strength with notch kJ/m.sup.2 7.1 8.9 7.3 9.8 7.1 8.2 8.2 7.7 7.7 6 Vicat Softening Temperature 50N 114 112 114 113 113 115 114 113 113 121 MFR 220° C., 98N 10.2 12.0 10.0 12.6 12.6 9.9 10.3 10.5 10.5 10.0 chemical resistance — A A A A B A A A A A

TABLE-US-00004 TABLE 4 Comparative Example 1 2 3 4 5 6 7 8 9 10 maleimide based copolymer used — B-1 B-2 B-3 B-4 B-5 B-6 B-1 B-7 A-2 MS-NIP evaluation formulation amount GR-3000 mass % 80 80 80 80 80 80 80 55 80 of Luran S 757G mass % 80 property maleimide based mass % 20 20 20 20 20 20 20 20 45 20 copolymer Charpy Impact Strength with notch kJ/m.sup.2 8.2 8.7 9.3 10.4 4.5 5.7 5.6 4.5 3.1 8.7 Vicat Softening Temperature 50N 114 114 109 116 108 107 111 112 126 113 MFR 220° C., 98N 6.5 7.1 12.2 7.0 10.7 11.7 7.2 10.7 5.6 11.3 chemical resistance — B B B C D D A D C D

(Charpy Impact Strength)

[0097] The Charpy impact strength was measured using a notched specimen in accordance with JIS K-7111. Edgewise was adopted as the striking direction, relative humidity was 50%, and atmospheric temperature was 23° C. Here, digital impact tester available from Toyo Seiki Seisaku-sho, Ltd. was used as the measuring instrument.

(Vicat Softening Temperature)

[0098] The vicat softening temperature was measured in accordance with JIS K7206. Here, Method 50 (load: 50N, temperature elevation rate 50° C./hour) was used, and the test piece having the size of 10 mm×10 mm and 4 mm thickness was used. HDT & VSPT testing device available from Toyo Seiki Seisaku-sho, Ltd. was used as the measuring instrument.

(Melt Mass Flow Rate; MFR)

[0099] Melt mass flow rate was measured at 220° C. with 98 N load in accordance with JIS K7210.

(Chemical Resistance)

[0100] Cracks of a test piece having a shape of 316×20×2 mm were observed after 48 hours at 23° C. by a quarter ellipse method having a major radius of 250 mm and a minor radius of 150 mm. In order to eliminate influence of molding strain, the test piece was prepared by press molding the pellet at 260° C. and then cutting out the test piece. Toluene was used as the chemical.

[0101] Critical strain was obtained by the following equation.

ε=b/2a.sup.2[1−(a.sup.2−b.sup.2)X.sup.2/a.sup.4].sup.1.5×t×100

[0102] Critical strain: ε, major radius: a, minor radius: b, thickness of test piece: t, crack initiation point: X

[0103] The chemical resistance was evaluated from the critical strain according to the following criteria.

[0104] A: 0.8 or more, B: 0.6 to 0.7, C: 0.3 to 0.5, D: 0.2 or less

[0105] As can be seen from Example 1 to Example 8, the maleimide based copolymers A-1 to A-8 of the present invention were able to realize high glass transition temperature and high melt mass flow rate by decreasing the weight average molecular weight without decreasing the content of the maleimide monomer unit in the composition. However, when the weight average molecular weight was decreased below a certain level, as can be seen in Comparative Example 5 and Comparative Example 6, decrease in heat resistance and decrease in chemical resistance were seen. The maleimide based copolymers B-1 to B-6 are out of the range of the claims of the present invention. The resin compositions of Comparative Example 1 to Comparative Example 6 which were prepared by kneading and mixing these maleimide based copolymers with ABS resin showed inferior results in at least one of impact resistance, flowability, heat resistance, and chemical resistance.

INDUSTRIAL APPLICABILITY

[0106] The maleimide based copolymer of the present invention can provide a resin composition superior in the balance of properties of chemical resistance, heat resistance, impact resistance, and flowability, by kneading and mixing with compatible ABS resin, ASA resin, AES resin, or SAN resin. The maleimide based copolymer of the present invention can also improve flowability of the mixed resin. Therefore, faster molding and higher productivity can be achieved.