THERMOPLASTIC RESIN COMPOSITION

Abstract

The present invention relates to a thermoplastic resin composition comprising: 100 parts by weight of a base resin comprising a first polymer obtained by graft polymerization of an aromatic vinyl-based monomer and a vinyl cyanide-based monomer to a diene-based rubber polymer, a second polymer comprising maleimide-based monomer units, maleic acid-based monomer units, and aromatic vinyl-based monomer units, and a third polymer comprising aromatic vinyl-based monomer units and vinyl cyanide-based monomer units; and 1 part by weight to 3 parts by weight of a fourth polymer comprising polyvinyl alcohol.

Claims

1. A thermoplastic resin composition comprising: 100 parts by weight of a base resin comprising a first polymer obtained by graft polymerization of an aromatic vinyl-based monomer and a vinyl cyanide-based monomer to a diene-based rubber polymer, a second polymer comprising maleimide-based monomer units, maleic acid-based monomer units, and aromatic vinyl-based monomer units, and a third polymer including aromatic vinyl-based monomer units and vinyl cyanide-based monomer units; and 1 part by weight to 3 parts by weight of a fourth polymer comprising polyvinyl alcohol.

2. The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition comprises: 100 parts by weight of the base resin; and 1.5 parts by weight to 2.5 parts by weight of the fourth polymer.

3. The thermoplastic resin composition of claim 1, wherein the thermoplastic resin composition comprises, with respect to 100 parts by weight of the base resin, 20 parts by weight to 40 parts by weight of the first polymer, 5 parts by weight to 25 parts by weight of the second polymer, and 50 parts by weight to 70 parts by weight of the third polymer.

4. The thermoplastic resin composition of claim 1, wherein the diene-based rubber polymer of the first polymer has an average particle diameter of 200 nm to 400 nm.

5. The thermoplastic resin composition of claim 1, wherein the second polymer has a glass transition temperature of 180° C. to 210° C.

6. The thermoplastic resin composition of claim 1, wherein the second polymer has a melt flow index of 1 g/10 min to 5 g/10 min under conditions of 265° C. and 10 kg in accordance with ASTM D1238.

Description

EXAMPLES AND COMPARATIVE EXAMPLES

[0038] Descriptions of components used in the following examples and comparative examples are as follows.

[0039] First polymer: DP270 manufactured by LC CHEM LTD. (graft polymer obtained by graft polymerization of styrene and acrylonitrile to a butadiene rubber polymer (average particle diameter: 300 nm)

[0040] Second polymer: MSNB manufactured by DENKA (an n-phenyl maleimide/maleic anhydride/styrene copolymer)

[0041] Third polymer: 92HR manufactured by LG CHEM LTD. (a styrene/acrylonitrile copolymer)

[0042] Fourth polymer: polyvinyl alcohol (Manufacturer: Sigma Aldrich. Product Number: 363146, weight average molecular weight: 85,000 g/mol to 124,000 g/mol, hydrolysis: 99% or more)

[0043] The above-described components were mixed according to the contents shown in the following table and stirred to prepare thermoplastic resin compositions.

Experimental Example 1

[0044] The thermoplastic resin compositions of the examples and comparative examples were extruded to prepare pellets. A physical property of the pellets was evaluated using the method described below, and the results thereof are shown in the table below.

[0045] {circle around (1)} Melt flow index (g/10 min): Measurement was performed under conditions of 220° C. and 10 kg in accordance with ASTM D1238.

Experimental Example 2

[0046] The thermoplastic resin compositions of the examples and comparative examples were extruded and injected to prepare specimens. The physical properties of the specimens were evaluated using the methods described below, and the results thereof are shown in the following table.

[0047] {circle around (2)} Chemical resistance (seconds): A specimen having a size of 200 mm×12.7 mm×3.2 mm was fixed to a curvature jig having a strain of 1.1%, and a 1 cc thinner was applied onto the specimen, and then the time taken for cracks to occur in the specimen was measured. When no cracks occurred until 600 seconds had elapsed after the application of the thinner, it was determined that chemical resistance evaluation was passed. Those that passed the chemical resistance evaluation were described as >600.

[0048] {circle around (3)} Paintability: A specimen having a size of 10 cm×10 cm was degreased using isopropyl alcohol, and then a black paint was sprayed onto the specimen. When 5 minutes had elapsed after spraying the paint, a clear paint was sprayed and dried in an oven at 85° C. to visually observe whether pin-holes were generated, and the paintability thereof was evaluated.

[0049] A: Excellent, B: Fair, C: Poor

[0050] {circle around (4)} Tensile strength (kgf/cm.sup.2): Measurement was performed in accordance with ASTM D638.

[0051] {circle around (5)} Heat deflection temperature (° C.): In accordance with ASTM D648-7, measurement was performed under conditions of ¼ inch, 18.6 kgf, and 120° C./hr.

TABLE-US-00001 TABLE 1 Comparative Comparative Example Example Example Classification 1 2 1 2 3 4 3 4 First polymer 25 25 25 25 25 25 25 25 Second 15 15 15 15 15 15 15 0 polymer Third polymer 60 60 60 60 60 60 60 75 Fourth 0 0.5 1 1.5 2 3 4 1 polymer Flow index 9.1 8.9 9 8.7 8.8 8.6 6.9 20.9 Chemical 238 350 >600 >600 >600 >600 >600 >600 resistance Paintability C C A A A A A A Tensile 482 480 475 475 469 469 440 498 strength Heat deflection 97.5 97.0 97.0 97.3 97.1 96.9 96.1 87 temperature First polymer: DP270 manufactured by LC CHEM LTD. (graft polymer obtained by graft polymerization of styrene and acrylonitrile to a butadiene rubber polymer (average particle diameter: 300 nm) Second polymer: MSNB manufactured by DENKA (an n-phenyl maleimide/maleic anhydride/styrene copolymer) Third polymer: 92HR manufactured by LG CHEM LTD. (a styrene/acrylonitrile copolymer) Fourth polymer: polyvinyl alcohol (Manufacturer: Sigma Aldrich. weight average molecular weight: 85,000 g/mol to 124,000 g/mol, hydrolysis: 99% or more)

[0052] Referring to the table, it was confirmed that Examples 1 to 4 including 1 part by weight to 3 parts by weight of polyvinyl alcohol had excellent chemical resistance, paintability, tensile strength, and heat deflection temperature. It was also confirmed that, since the melt flow index was at an appropriate level, processability was also excellent. In contrast, it was confirmed that Comparative Example 1 not including polyvinyl alcohol and Comparative Example 2 including a small amount of polyvinyl alcohol had deteriorated chemical resistance and paintability. From these results, it could be predicted that, when molded products manufactured from Comparative Examples 1 and 2 are used for painting, defects or peeling of paint and the like occur.

[0053] It was confirmed that Comparative Example 3 including excess polyvinyl alcohol exhibited excellent chemical resistance and paintability, but flow index, tensile strength, and heat deflection temperature were lowered. From these results, it could be predicted that a molded article manufactured from Comparative Example 3 exhibits deteriorated processability, rigidity, and heat resistance.

[0054] It was also confirmed that Comparative Example 5 not including the second polymer exhibited excellent chemical resistance, paintability, and tensile strength, but a melt flow index was too high and a heat deflection temperature was lowered. From these results, it could be predicted that a molded product manufactured from Comparative Example 5 exhibits deteriorated processability and heat resistance.