Thermoplastic resin composition and thermoplastic resin molded article

Abstract

Provided is a thermoplastic resin composition which includes: a first copolymer including an acrylic graft copolymer; a second copolymer including an alkyl-substituted styrene-based monomer unit, a vinyl cyanide-based monomer unit, and a (meth)acrylate-based monomer unit; and a third copolymer including an alkyl-unsubstituted styrene-based monomer unit, a vinyl cyanide-based monomer unit, and a (meth)acrylate-based monomer unit. According to the present invention, a thermoplastic resin composition and a thermoplastic resin molded article, which are excellent in heat resistance, colorability, and scratch resistance, can be provided.

Claims

1. A thermoplastic resin composition comprising: a first copolymer including an acrylic graft copolymer; a second copolymer including an alkyl-substituted styrene-based monomer unit, a vinyl cyanide-based monomer unit, and a methacrylate-based monomer unit; and a third copolymer including an alkyl-unsubstituted styrene-based monomer unit, a vinyl cyanide-based monomer unit, and a (meth)acrylate-based monomer unit, wherein the thermoplastic resin composition includes, with respect to 100 parts by weight of the sum of the first copolymer, the second copolymer, and the third copolymer: 20 to 50 parts by weight of the first copolymer; 20 to 45 parts by weight of the second copolymer; and 15 to 40 parts by weight of the third copolymer.

2. The thermoplastic resin composition of claim 1, wherein the first copolymer includes: a first acrylic graft copolymer formed by graft copolymerization of an acrylic rubber polymer having an average particle diameter of 300 to 650 nm with a vinyl-based monomer; and a second acrylic graft copolymer formed by graft copolymerization of an acrylic rubber polymer having an average particle diameter of 30 to 250 nm with a vinyl-based monomer.

3. The thermoplastic resin composition of claim 2, wherein the first copolymer includes the first acrylic graft copolymer and the second acrylic graft copolymer in a weight ratio of 5:95 to 25:75.

4. The thermoplastic resin composition of claim 1, wherein the second copolymer is a copolymer of a monomer mixture including an alkyl-substituted styrene-based monomer at 30 to 50 wt %, a vinyl cyanide-based monomer at 20 to 40 wt %, and a (meth)acrylate-based monomer at 20 to 40 wt %.

5. The thermoplastic resin composition of claim 1, further comprising a (meth)acrylate-based polymer.

6. The thermoplastic resin composition of claim 5, wherein the (meth)acrylate-based polymer is poly(methyl methacrylate).

7. The thermoplastic resin composition of claim 5, wherein the thermoplastic resin composition includes the (meth)acrylate-based polymer in an amount of 1 to 20 parts by weight with respect to 100 parts by weight of the sum of the first copolymer, the second copolymer, the third copolymer, and the (meth)acrylate-based polymer.

8. The thermoplastic resin composition of claim 1, further comprising an additive including a silicone compound.

9. The thermoplastic resin composition of claim 8, wherein the thermoplastic resin composition includes the additive in an amount of 0.1 to 3 parts by weight with respect to 100 parts by weight of the sum of the first copolymer, the second copolymer, and the third copolymer.

10. A thermoplastic resin molded article made of the thermoplastic resin composition of claim 1 and having a heat deflection temperature of 90° C. or more, an L value of 25.5 or less, and a pencil hardness of F or more.

11. The thermoplastic resin composition of claim 1, wherein the (meth)acrylate-based monomer unit of the third copolymer is a methacrylate-based monomer unit.

12. The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition further includes poly(methyl methacrylate) in an amount of 1 to less than 15 parts by weight with respect to 100 parts by weight of the sum of the first copolymer, the second copolymer, the third copolymer, and the (poly(methyl methacrylate).

Description

Examples and Comparative Examples

(1) The specifications of components used in Examples and Comparative Examples are as follows.

(2) (A) Acrylic Graft Copolymer

(3) (A-1) First acrylic graft copolymer: SA927 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 450 nm with styrene and acrylonitrile) was used.

(4) (A-2) Second acrylic graft copolymer: SA100 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 100 nm with styrene and acrylonitrile) was used.

(5) (B) Alkyl-Substituted Styrene-Based Copolymer

(6) (B-1): The copolymer prepared in Preparation Example 1 was used.

(7) (B-2): 200UH commercially available from LG Chem Ltd. (α-methyl styrene/acrylonitrile copolymer) was used.

(8) (C) Alkyl-unsubstituted styrene-based copolymer: XT510 commercially available from LG Chem Ltd. (styrene/acrylonitrile/methyl methacrylate copolymer) was used.

(9) (D) (Meth)Acrylate-Based Polymer

(10) (D-1): IH830 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 98,000 g/mol) was used.

(11) (D-2): BA611 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 45,000 g/mol) was used.

(12) (D-3): BN600 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 24,000 g/mol) was used.

(13) (E) Silicone compound: TEGOMER 6441P commercially available from Evonik Industries was used.

(14) The above-described components were mixed in contents shown in Table 1 to Table 3 and stirred to prepare thermoplastic resin compositions.

Experimental Example 1

(15) Each of the thermoplastic resin compositions of Examples and Comparative Examples was introduced into an extruder kneader (cylinder temperature: 240° C.) and then extruded to prepare pellets. Physical properties of the pellets were evaluated by methods described below, and results thereof are shown in Table 1 to Table 3.

(16) (1) Melt flow index (g/10 min): measured by weighing the pellet under conditions of 220° C. and a 10 kg load for 10 minutes using MI-4 commercially available from GOETTFERT in accordance with ASTM D1238.

(17) (2) Heat deflection temperature (° C.): measured using an auto HDT tester 6A-2 (manufactured by TOYO SEIKI SEISAKY-SHO Ltd.) in accordance with ASTM D648.

Experimental Example 2

(18) Each of the pellets prepared in Experimental Example 1 was injection-molded to prepare a specimen. Physical properties of the specimen were evaluated by methods described below, and results thereof are shown in Table 1 to Table 3.

(19) (1) IZOD impact strength (kg.Math.cm/cm, Notched, ¼ In): measured at 23° C. using an impact tester manufactured by TOYO SEIKI SEISAKY-SHO Ltd. in accordance with ASTM D256.

(20) (2) Colorability: determined by measuring the L value in a SCI mode using Color-Eye 7000A commercially available from GretagMacbeth.

(21) (3) Pencil hardness: Scratch resistance was measured by visually examining whether the surface of the specimen was scratched while applying a scratch on the surface with a pencil maintained under a 0.5 kg load at an angle of 45° while varying the pencil hardness.

(22) TABLE-US-00001 TABLE 1 Comparative Comparative Classification Example 1 Example 1 Example 2 Example 2 Example 3 (A) Acrylic graft (A-1) 5 5 5 5 5 copolymer (parts by weight) (A-2) 30 30 30 30 30 (B) Alkyl- (B-1) — 35 — 35 40 substituted (B-2) 35 — 35 — — styrene-based copolymer (parts by weight) (C) Alkyl-unsubstituted 30 30 30 30 25 styrene-based copolymer (parts by weight) (D) (D-1) — — — — — (Meth)acrylate- (D-2) — — — — — based polymer (D-3) — — — — — (parts by weight) (E) Silicone compound — — 1 1 1 (parts by weight) Melt flow index 8 8 8 8 8 Heat deflection 91 90 90 90 93 temperature IZOD impact strength 9 9 9 9 9 Colorability 25.9 25.4 25.9 25.4 25.5 Pencil hardness HB F F H H (A) Acrylic graft copolymer (A-1) First acrylic graft copolymer: SA927 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 450 nm with styrene and acrylonitrile) (A-2) Second acrylic graft copolymer: SA100 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 100 nm with styrene and acrylonitrile) (B) Alkyl-substituted styrene-based copolymer (B-1): Copolymer prepared in Preparation Example 1 (α-methyl styrene/acrylonitrile/methyl methacrylate copolymer) (B-2): 200UH commercially available from LG Chem Ltd. (α-methyl styrene/acrylonitrile copolymer) (C) Alkyl-unsubstituted styrene-based copolymer: XT510 commercially available from LG Chem Ltd. (styrene/acrylonitrile/methyl methacrylate copolymer) (D) (Meth)acrylate-based polymer (D-1): IH830 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 98,000 g/mol) (D-2): BA611 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 45,000 g/mol) (D-3): BN600 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 24,000 g/mol) (E) Silicone compound: TEGOMER 6441P commercially available from Evonik Industries

(23) TABLE-US-00002 TABLE 2 Comparative Exam- Exam- Exam- Classification Example 3 ple 4 ple 5 ple 6 (A) Acrylic graft (A-1) 5 5 5 5 copolymer (A-2) 30 30 30 30 (parts by weight) (B) Alkyl- (B-1) — 35 35 35 substituted styrene- (B-2) 35 — — — based copolymer (parts by weight) (C) Alkyl-unsubstituted 20 20 20 20 styrene-based copolymer (parts by weight) (D) (Meth)acrylate- (D-1) 10 10 — — based polymer (D-2) — — 10 — (parts by weight) (D-3) — — — 10 (E) Silicone compound 1 1 1 1 (parts by weight) Melt flow index 8 8 12 14 Heat deflection temperature 91 91 91 90 IZOD impact strength 9 9 9 9 Colorability 25.7 25.2 25.2 25.2 Pencil hardness F H H H (A) Acrylic graft copolymer (A-1) First acrylic graft copolymer: SA927 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 450 nm with styrene and acrylonitrile) (A-2) Second acrylic graft copolymer: SA100 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 100 nm with styrene and acrylonitrile) (B) Alkyl-substituted styrene-based copolymer (B-1): Copolymer prepared in Preparation Example 1 (α-methyl styrene/acrylonitrile/methyl methacrylate copolymer) (B-2): 200UH commercially available from LG Chem Ltd. (α-methyl styrene/acrylonitrile copolymer) (C) Alkyl-unsubstituted styrene-based copolymer: XT510 commercially available from LG Chem Ltd. (styrene/acrylonitrile/methyl methacrylate copolymer) (D) (Meth)acrylate-based polymer (D-1): IH830 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 98,000 g/mol) (D-2): BA611 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 45,000 g/mol) (D-3): BN600 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 24,000 g/mol) (E) Silicone compound: TEGOMER 6441P commercially available from Evonik Industries

(24) TABLE-US-00003 TABLE 3 Comparative Examples Classification 4 5 6 (A) Acrylic graft (A-1) 5 5 5 copolymer (A-2) 30 30 30 (parts by weight) (B) Alkyl-substituted (B-1) — — 65 styrene-based (B-2) — — — copolymer (parts by weight) (C) Alkyl-unsubstituted 65 — — styrene-based copolymer (parts by weight) (D) (Meth)acrylate- (D-1) — 65 — based polymer (D-2) — — — (parts by weight) (D-3) — — — (E) Silicone compound 1 1 1 (parts by weight) Melt flow index 8 4 7 Heat deflection temperature 83 87 96 IZOD impact strength 7 6 9 Colorability 25.1 24.8 25.7 Pencil hardness F H F (A) Acrylic graft copolymer (A-1) First acrylic graft copolymer: SA927 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 450 nm with styrene and acrylonitrile) (A-2) Second acrylic graft copolymer: SA100 commercially available from LG Chem Ltd. (graft copolymer formed by graft polymerization of a butyl acrylate rubber polymer having an average particle diameter of 100 nm with styrene and acrylonitrile) (B) Alkyl-substituted styrene-based copolymer (B-1): Copolymer prepared in Preparation Example 1 (α-methyl styrene/acrylonitrile/methyl methacrylate copolymer) (B-2): 200UH commercially available from LG Chem Ltd. (α-methyl styrene/acrylonitrile copolymer) (C) Alkyl-unsubstituted styrene-based copolymer: XT510 commercially available from LG Chem Ltd. (styrene/acrylonitrile/methyl methacrylate copolymer) (D) (Meth)acrylate-based polymer (D-1): IH830 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 98,000 g/mol) (D-2): BA611 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 45,000 g/mol) (D-3): BN600 commercially available from LG MMA Corp. (poly(methyl methacrylate), weight-average molecular weight: 24,000 g/mol) (E) Silicone compound: TEGOMER 6441P commercially available from Evonik Industries

(25) Referring to Table 1, the thermoplastic resin composition of Example 1, which included an α-methyl styrene/acrylonitrile/methyl methacrylate copolymer, was excellent in colorability and scratch resistance compared to the thermoplastic resin composition of Comparative Example 1 which included a styrene/acrylonitrile/methacrylate copolymer. In addition, the thermoplastic resin composition of Example 2, which included an α-methyl styrene/acrylonitrile/methyl methacrylate copolymer and a silicone compound, was excellent in colorability and scratch resistance compared to the thermoplastic resin composition of Comparative Example 2 which included a styrene/acrylonitrile/methacrylate copolymer and a silicone compound.

(26) As a result of comparing Example 1 and Example 2, the thermoplastic resin composition of Example 2, which further included a silicone compound, exhibited excellent scratch resistance compared to the thermoplastic resin composition of Example 1.

(27) As a result of comparing Example 2 and Example 3, the thermoplastic resin composition of Example 3, which included an excessive amount of an α-methyl styrene/acrylonitrile/methyl methacrylate copolymer, was excellent in heat resistance but exhibited slightly degraded colorability compared to the thermoplastic resin composition of Example 2.

(28) Referring to Table 2, even when poly(methyl methacrylate) was further included, the thermoplastic resin compositions of Examples 4 to 6, which included an α-methyl styrene/acrylonitrile/methyl methacrylate copolymer, were excellent in colorability and scratch resistance compared to the thermoplastic resin composition of Comparative Example 3 which included a styrene/acrylonitrile/methacrylate copolymer.

(29) As a result of comparing Examples 2 and 4 to 6, even though poly(methyl methacrylate) did not greatly affect the physical properties of the thermoplastic resin composition, when poly(methyl methacrylate) having a low weight-average molecular weight was used, a melt flow index was increased, and thus processability was improved.

(30) Referring to Table 3, in the case of the thermoplastic resin composition of Comparative Example 4 which did not include an α-methyl styrene/acrylonitrile/methyl methacrylate copolymer, a heat deflection temperature and impact strength were significantly degraded. In addition, in the case of the thermoplastic resin composition of Comparative Example 5 which did not include an α-methyl styrene/acrylonitrile/methyl methacrylate copolymer and a styrene/acrylonitrile copolymer, a melt flow index, a heat deflection temperature, and impact strength were significantly degraded. Additionally, in the case of the thermoplastic resin composition of Comparative Example 6 which did not include a styrene/acrylonitrile copolymer, colorability was significantly degraded.