Thermoplastic resin composition

Abstract

Provided is a thermoplastic resin composition which includes: a first graft copolymer including a C.sub.4 to C.sub.10 alkyl (meth)acrylate-based monomer unit, a C.sub.1 to C.sub.3 alkyl-substituted styrene-based monomer unit, and a vinyl cyan-based monomer unit; a second graft copolymer including a C.sub.4 to C.sub.10 alkyl (meth)acrylate-based monomer unit, an alkyl-unsubstituted styrene-based monomer unit, and a vinyl cyan-based monomer unit; a first styrene-based copolymer including a C.sub.1 to C.sub.3 alkyl-substituted styrene-based monomer unit and a vinyl cyan-based monomer unit; a second styrene-based copolymer including an alkyl-unsubstituted styrene-based monomer unit and a vinyl cyan-based monomer unit; and an olefin-based copolymer including a C.sub.1 to C.sub.3 alkyl (meth)acrylate-based monomer unit. The thermoplastic resin composition exhibits remarkably excellent chemical resistance and remarkably excellent appearance characteristics while maintaining basic properties.

Claims

1. A thermoplastic resin composition comprising: a first graft copolymer including a C.sub.4 to C.sub.10 alkyl (meth)acrylate-based monomer unit, a C.sub.1 to C.sub.3 alkyl-substituted styrene-based monomer unit, and a vinyl cyan-based monomer unit; a second graft copolymer including a C.sub.4 to C.sub.10 alkyl (meth)acrylate-based monomer unit, an alkyl-unsubstituted styrene-based monomer unit, and a vinyl cyan-based monomer unit; a first styrene-based copolymer including a C.sub.1 to C.sub.3 alkyl-substituted styrene-based monomer unit and a vinyl cyan-based monomer unit; a second styrene-based copolymer including an alkyl-unsubstituted styrene-based monomer unit and a vinyl cyan-based monomer unit; and an olefin-based copolymer including a C.sub.1 to C.sub.3 alkyl (meth)acrylate-based monomer unit.

2. The thermoplastic resin composition of claim 1, wherein the first graft copolymer further includes an alkyl-unsubstituted styrene-based monomer unit.

3. The thermoplastic resin composition of claim 1, wherein the first graft copolymer and the second graft copolymer have cores having mutually different average particle diameters.

4. The thermoplastic resin composition of claim 1, wherein the first graft copolymer has a core having an average particle diameter of 300 to 500 nm.

5. The thermoplastic resin composition of claim 1, wherein the second graft copolymer has a core having an average particle diameter of 50 to 150 nm.

6. The thermoplastic resin composition of claim 1, wherein the olefin-based copolymer includes a C.sub.2 to C.sub.4 olefin-based monomer unit and the C.sub.1 to C.sub.3 alkyl (meth)acrylate-based monomer unit in a weight ratio of 85:15 to 65:35.

7. The thermoplastic resin composition of claim 1, wherein the olefin-based copolymer has a weight-average molecular weight of 50,000 to 200,000 g/mol.

8. The thermoplastic resin composition of claim 1, which includes, with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer, 0.01 to 2 parts by weight of the olefin-based copolymer.

9. The thermoplastic resin composition of claim 1, which includes, with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer, 0.5 to 1 part by weight of the olefin-based copolymer.

10. The thermoplastic resin composition of claim 1, wherein the sum of the content of the first graft copolymer and the content of the second graft copolymer is 10 to 35 parts by weight with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer.

11. The thermoplastic resin composition of claim 10, wherein a weight ratio of the first graft copolymer and the second graft copolymer is 1.5:1 to 10:1.

12. The thermoplastic resin composition of claim 1, wherein the sum of the content of the first styrene-based copolymer and the content of the second styrene-based copolymer is 65 to 90 parts by weight with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer.

13. The thermoplastic resin composition of claim 12, wherein the first styrene-based copolymer is included in an amount of 14 to 20 parts by weight with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer.

14. The thermoplastic resin composition of claim 1, which includes, with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer: 5 to 30 parts by weight of the first graft copolymer; 0.1 to 15 parts by weight of the second graft copolymer; 2 to 25 parts by weight of the first styrene-based copolymer; and 50 to 80 parts by weight of the second styrene-based copolymer.

15. The thermoplastic resin composition of claim 1, which includes, with respect to 100 parts by weight of the sum of the first graft copolymer, the second graft copolymer, the first styrene-based copolymer, and the second styrene-based copolymer: 10 to 15 parts by weight of the first graft copolymer; 5 to 8 parts by weight of the second graft copolymer; 14 to 16 parts by weight of the first styrene-based copolymer; 62 to 66 parts by weight of the second styrene-based copolymer; and 0.3 to 0.6 part by weight of the olefin-based copolymer.

Description

EXAMPLES AND COMPARATIVE EXAMPLES

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

(2) (A-1) First graft copolymer: The graft copolymer powder prepared in Preparation Example 1 was used.

(3) (A-2) Second graft copolymer: The graft copolymer powder prepared in Preparation Example 2 was used.

(4) (B-1) First styrene-based copolymer: 98UHM (commercially available from LG Chem Ltd., α-methylstyrene/acrylonitrile copolymer, weight-average molecular weight: 100,000 g/mol) was used.

(5) The weight-average molecular weight was measured as a relative value with respect to a standard PS sample by GPC (Waters Breeze) using THF as an eluate.

(6) (B-2) Second styrene-based copolymer: 97HC (commercially available from LG Chem Ltd., styrene/acrylonitrile copolymer, weight-average molecular weight: 170,000 g/mol) was used.

(7) The weight-average molecular weight was measured as a relative value with respect to a standard PS sample by GPC (Waters Breeze) using THF as an eluate.

(8) (C) Olefin-based copolymer: The copolymer prepared in Preparation Example 3 was used.

(9) The above-described components were mixed in contents shown in the following [Table 1] and stirred to prepare thermoplastic resin compositions.

Experimental Example 1

(10) Each of the thermoplastic resin compositions of Examples and Comparative Examples was put into a twin-screw extruder kneader set at 230° C. to prepare pellets. A physical property of the pellet was evaluated by the method described below, and results thereof are shown in the following [Table 1].

(11) (1) Melt flow index (g/10 min): measured in accordance with ASTM D1238 at 220° C.

Experimental Example 2

(12) The pellet 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 the following [Table 1].

(13) (2) Hardness: measured in accordance with ASTM 785.

(14) (3) IZOD impact strength (kg cm/cm): measured in accordance with ASTM 256.

(15) (4) Heat deflection temperature (° C.): measured in accordance with ASTM D648.

Experimental Example 3

(16) The pellet prepared in Experimental Example 1 was extruded through a film extruder to form a 0.3-mm film. Physical properties of the film were evaluated by methods described below, and results thereof are shown in the following [Table 1].

(17) (5) Film appearance: determined by evaluating pressure marks and bumps on the film through visual inspection.

(18) x: deformed film, ∘: good, ⊚: excellent

(19) (6) Chemical resistance: evaluated based on the time required for the film to start dissolving after the film was immersed in a beaker containing methyl ethyl ketone for 2 minutes.

(20) x: 20 seconds or less, ∘: more than 40 seconds and less than 100 seconds, and ⊚: 100 seconds or more

(21) TABLE-US-00001 TABLE 1 Examples Comparative Examples Classification 1 2 3 4 5 1 2 3 4 5 (A-1) First 14 19 15 14 17 3 14 14 — 22 graft copolymer (parts by weight) (A-2) Second 7 2 6 7 4 35 7 7 23 — graft copolymer (parts by weight) (B-1) First 15 12 12 15 12 — 79 15 15 15 styrene-based copolymer (B-2) Second 64 67 67 64 67 62 — 64 62 63 styrene-based copolymer (C) Olefin- 0.5 0.5 0.5 0.7 0.5 0.5 0.5 — 0.5 0.5 based copolymer Melt flow index 10.1 12.4 13 10.3 12.7 7.7 9.9 9 15.8 8.7 Hardness 112.6 112 112.3 112 112.1 104 111.9 114 113 112 Impact strength 7.1 7.1 6.7 6.6 6.9 6 7.9 7.7 4.4 7 Heat deflection 91.3 89.3 89.4 90 89.3 85 98.5 91.5 90.5 90 temperature Film appearance ⊚ ◯ ◯ ⊚ ◯ X ⊚ ⊚ X X characteristics Chemical ⊚ ⊚ ⊚ ⊚ ⊚ ◯ X X ⊚ X resistance

(22) Referring to Table 1, it can be seen that Example 1 to Example 5 were excellent in terms of a melt flow index, hardness, impact strength, film appearance characteristics, and chemical resistance and also exhibited high heat deflection temperatures.

(23) On the other hand, it can be seen that Comparative Example 1 not including a first styrene-based copolymer exhibited significantly degraded properties in terms of a melt flow index, heat deflection temperature, and impact strength compared to Examples and also exhibited poor film appearance characteristics.

(24) It can be seen that Comparative Example 2 not including a second styrene-based copolymer and Comparative Example 3 not including a third copolymer exhibited significantly degraded properties in terms of a melt flow index and chemical resistance.

(25) It can be seen that Comparative Example 4 not including a first graft copolymer exhibited significantly degraded impact strength and also exhibited poor film appearance characteristics.

(26) It can be seen that Comparative Example 5 not including a second graft copolymer exhibited poor chemical resistance and poor film appearance characteristics.

(27) It can be predicted from these results that only when all of the components according to the present invention are included, a thermoplastic resin molded article excellent in all of processability, hardness, impact resistance, heat resistance, chemical resistance, and appearance characteristics can be prepared.