THERMOPLASTIC RESIN COMPOSITION, METHOD OF PREPARING THE SAME, AND MOLDED ARTICLE INCLUDING THE SAME

Abstract

The present invention relates to a thermoplastic resin composition, a method of preparing the same, and a molded article including the same, and more particularly, to a thermoplastic resin composition having eco-friendliness and excellent molding processability, mechanical rigidity, heat resistance, and colorability by including a predetermined ASA-based graft copolymer and a recycled resin, a method of preparing the thermoplastic resin composition, and a molded article including the thermoplastic resin composition.

Claims

1. A thermoplastic resin composition, comprising: an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) containing an alkyl acrylate rubber core having an average particle diameter of 60 to 200 nm and an aromatic vinyl compound-vinyl cyanide compound copolymer shell; and a matrix resin (B), wherein the copolymer shell of the graft copolymer (A) comprises 85 to 99% by weight of an aromatic vinyl compound and 1 to 15% by weight of a vinyl cyanide compound based on a total weight of the copolymer shell and has a weight average molecular weight of 100,000 to 400,000 g/mol, and the matrix resin (B) comprises 50 to 90% by weight of recycled polystyrene and 8 to 50% by weight of a polyarylene oxide based on 100% by weight in total of the matrix resin (B).

2. The thermoplastic resin composition according to claim 1, wherein, based on 100% by weight in total of the graft copolymer (A) and the matrix resin (B), the thermoplastic resin composition comprises 20 to 60% by weight of the graft copolymer (A) and 40 to 80% by weight of the matrix resin (B).

3. The thermoplastic resin composition according to claim 1, wherein, based on 100% by weight in total of the graft copolymer (A), the graft copolymer (A) comprises 40 to 70% by weight of the alkyl acrylate rubber core and 30 to 60% by weight of the copolymer shell.

4. The thermoplastic resin composition according to claim 1, wherein, based on 100% by weight in total of the graft copolymer (A), the graft copolymer (A) comprises 1 to 20% by weight of a polymer seed comprising one or more selected from the group consisting of an alkyl (meth)acrylate, an aromatic vinyl compound, and a vinyl cyanide compound, 35 to 65% by weight of the alkyl acrylate rubber core, and 30 to 60% by weight of the copolymer shell.

5. The thermoplastic resin composition according to claim 1, wherein the recycled polystyrene comprises any one selected from the group consisting of recycled non-foamed polystyrene, recycled foamed polystyrene, and a mixture thereof.

6. The thermoplastic resin composition according to claim 1, wherein the recycled polystyrene has a weight average molecular weight of 100,000 to 350,000 g/mol.

7. The thermoplastic resin composition according to claim 1, wherein the matrix resin (B) further comprises general-purpose polystyrene.

8. The thermoplastic resin composition according to claim 1, wherein the matrix resin (B) further comprises 1 to 15% by weight of an aromatic vinyl compound-vinyl cyanide compound copolymer comprising 75 to 95% by weight of an aromatic vinyl compound and 5 to 25% by weight of a vinyl cyanide compound.

9. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition comprises an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (C) containing an alkyl acrylate rubber core having an average particle diameter of greater than 200 nm and 500 nm or less and an aromatic vinyl compound-vinyl cyanide compound copolymer shell.

10. The thermoplastic resin composition according to claim 9, wherein, based on 100 parts by weight in total of the graft copolymer (A) and the matrix resin (B), the graft copolymer (C) is comprised in an amount of 0.1 to 12 parts by weight.

11. The thermoplastic resin composition according to claim 1, wherein, based on 100 parts by weight in total of the graft copolymer (A) and the matrix resin (B), the thermoplastic resin composition comprises a light stabilizer (D) in an amount of 0.1 to 7 parts by weight.

12. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a heat deflection temperature (HDT) of 82 C. or higher as measured under a load of 18.5 kgf according to ASTM D 648.

13. The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition has a tensile strength of 400 kgf/cm.sup.2 or more as measured at a rate of 50 mm/min according to ASTM D 638.

14. A method of preparing a thermoplastic resin composition, comprising kneading and extruding an alkyl acrylate-aromatic vinyl compound-vinyl cyanide compound graft copolymer (A) containing an alkyl acrylate rubber core having an average particle diameter of 60 to 200 nm and an aromatic vinyl compound-vinyl cyanide compound copolymer shell, and a matrix resin (B) at 180 to 300 C. and 100 to 400 rpm, wherein the copolymer shell of the graft copolymer (A) comprises 85 to 99% by weight of an aromatic vinyl compound and 1 to 15% by weight of a vinyl cyanide compound based on a total weight of the copolymer shell and has a weight average molecular weight of 100,000 to 400,000 g/mol, and the matrix resin (B) comprises 50 to 90% by weight of recycled polystyrene and 8 to 50% by weight of a polyarylene oxide based on a total weight of the matrix resin (B).

15. A molded article, comprising the thermoplastic resin composition according to claim 1.

Description

EXAMPLES

[0197] Materials used in the following examples and comparative examples are as follows. [0198] (A) ASA graft copolymer: An ASA graft copolymer including a butyl acrylate seed polymer; a butyl acrylate rubber core; and a styrene-acrylonitrile copolymer shell is used. The average particle diameters of the seed and core and the composition and weight average molecular weight of the shell satisfy the conditions shown in Table 1 below (Based on a total weight of the ASA graft copolymer (A), 7% by weight of the seed polymer, 43% by weight of the rubber core, and 50% by weight of the copolymer shell are included).

TABLE-US-00001 TABLE 1 (A) ASA graft copolymer Core Shell Average particle AN content Mw diameter (nm) (wt %) (g/mol) A-1 100 2 212,000 A-2 100 5 224,000 A-3 100 10 241,000 A-4 100 15 253,000 A-5 100 5 110,000 A-6 100 5 395,000 A-7 150 5 226,000 A-8 400 5 221,000 A-9 100 0 225,000 A-10 100 17 226,000 A-11 100 5 85,000 A-12 100 5 450,000

[0199] (In Table 1, in the case of A-9, a vinyl cyanide compound is not included, but for convenience of comparison, A-9 is classified as the ASA graft copolymer (A), AN represents acrylonitrile, MW represents weight average molecular weight, and the AN content of a shell means wt % of AN based on a total weight of the shell.) [0200] (B) Matrix resins: [0201] (B-1) Recycled PS resin (non-foamed PS) (Mw: 240,000 g/mol) [0202] (B-2) Recycled EPS resin (Mw: 165,000 g/mol) [0203] (B-3) Virgin GPPS (25SPI, MW: 275,000 g/mol, LG Chemical Co.) [0204] (B-4) PPO: Poly(2,6-dimethyl-1,4-phenylene)oxide (LXR035, Bluestar Co.) having an intrinsic viscosity of 0.32 dl/g and a melt flow index of 28 g/10 min as measured at 220 C. under a load of 10 kg according to ASTM D1238 [0205] (B-5) SAN resin (82TR SAN, LG Chemical Co.) [0206] (C) Large-diameter ASA resin (SA927, LG Chemical Co.) containing a butylacrylate rubber core having an average particle diameter of 380 to 500 nm

Examples 1 to 13 and Comparative Examples 1 to 10

[0207] According to the contents shown in Table 2, (A) to (C) were mixed using a super mixer, and then extruded at a cylinder temperature of 260 C. and a screw rotation rate of 200 rpm using a twin-screw extruder (screw diameter: 26 mm, L/D=40) to obtain pellets.

[0208] The obtained thermoplastic resin composition in the form of pellets was dried at 80 C. for 2 hours or more, and then injection-molded at a barrel temperature of 230 C., a mold temperature of 60 C., and an injection speed of 30 mm/see using an injection machine to obtain a specimen for measuring physical properties. Then, after leaving the specimen at room temperature for more than 48 hours, the physical properties thereof were measured.

TEST EXAMPLES

[0209] The physical properties of the specimens prepared in examples and comparative examples were measured in the following methods, and the results are shown in Table 3 below. [0210] Melt flow index (g/10 min): A load of 10 kg was applied at a temperature of 220 C. for 10 minutes according to ASTM D1238 to melt a resin. At this time, the weight (g) of the melted resin flowing out was measured. [0211] Izod impact strength (kgf.Math.cm/cm): Izod impact strength was measured at room temperature using an injection specimen having a thickness of according to ASTM D256. [0212] Tensile strength (kgf/cm.sup.2): Tensile strength was measured at a rate of 50 mm/min and room temperature using an injection specimen having a thickness of according to ASTM D 638. [0213] Heat deflection temperature ( C.): Heat deflection temperature (HDT) was measured under a load of 18.5 kgf according to ASTM D648. [0214] Colorability (C/S): Colorability was measured at a degree observer of 10 under a UV D65 light source using X-lite Color-eye 7000A equipment according to the CIE Lab method. L and b values were obtained in a reflectance mode using a Munsell System according to the CIE Lab method. Then, based on the measured L and b values, a colorability C/S (color strength) value was calculated based on a formula included in the software of Propalett Paint/Plastics Formulation Platinum 5.2.5.1. (GretagMacbeth LLC Co.). Here, the C/S value is based on 100. When the C/S value is greater than 100, colorability is considered excellent.

TABLE-US-00002 TABLE 2 Composition ratio of thermoplastic resin composition Matrix resin Dry Powder (DP) (B-1) (B-2) Classification (A) ASA Recycled Recycled (B-3) (B-4) (B-5) (wt %) Type Content (C) ASA PS EPS GPPS PPO SAN Examples 1 A-1 50 30 20 2 A-2 50 30 20 3 A-3 50 30 20 4 A-4 50 30 20 5 A-5 50 30 20 6 A-6 50 30 20 7 A-7 50 30 20 8 A-2 50 30 10 10 9 A-2 40 5 30 5 20 10 A-2 50 25 20 5 11 A-2 50 20 10 20 12 A-2 40 30 10 20 13 A-2 60 10 10 20 Comparative 1 A-8 50 30 20 Examples 2 A-9 50 30 20 3 A-10 50 30 20 4 A-11 50 30 20 5 A-12 50 30 20 6 A-2 50 30 20 7 A-2 50 15 35 8 A-2 50 48 2 9 A-2 80 20 10 A-2 10 30 40 20

TABLE-US-00003 TABLE 3 Impact Heat Melt flow strength Tensile deflection Color- index (kgf .Math. strength temperature ability Classification (g/10 min) cm/cm) (kgf/cm.sup.2) ( C.) (C/S) Examples 1 12.1 11.1 432 88.9 106.8 2 11.3 12.0 440 90.7 107.1 3 10.8 12.5 456 92.3 107.9 4 10.3 12.9 461 94.0 108.3 5 18.5 10.3 420 89.3 106.8 6 7.0 13.1 452 91.3 106.1 7 6.7 12.6 423 90.5 105.7 8 16.7 10.5 402 86.2 107.5 9 7.5 13.9 468 93.7 107.3 10 10.6 10.9 460 91.2 107.8 11 14.8 10.9 480 90.2 106.8 12 14.0 10.1 500 92.3 105.9 13 9.4 14.8 412 88.0 108.5 Compar- 1 5.3 14.6 345 89.6 100.0 ative 2 12.3 7.2 442 86.4 103.0 Examples 3 10.5 8.4 360 85.3 104.3 4 13.6 8.5 358 84.9 105.3 5 5.1 9.1 369 85.1 104.7 6 19.8 5.3 360 78.1 105.1 7 4.3 15.3 459 94.0 102.9 8 20.3 6.0 370 79.2 105.3 9 2.6 15.2 297.0 62.4 105.4 10 25.6 2.5 612.0 90.6 103.0

[0215] As shown in Tables 1 to 3, in the case of Examples 1 to 13 according to the present invention, even though recycled PS was included, melt flow index, impact strength, tensile strength, heat deflection temperature, and colorability were equal or superior to those of comparative examples. It was confirmed that Examples 1 to 13 had excellent molding processability, mechanical rigidity, heat resistance, and colorability.

[0216] On the other hand, in the case of Comparative Examples 1 to 5 using ASA in which the average particle diameter of the alkyl acrylate rubber included in the graft copolymer (A), the content of acrylonitrile included in the copolymer shell, and the weight average molecular weight of the copolymer shell were outside the ranges of the present invention, melt flow index, impact strength, tensile strength, and/or colorability were poor. In the case of Comparative Example 6 in which the matrix resin included only GPPS instead of PPO, mechanical rigidity and heat resistance were very poor. Meanwhile, referring to Comparative Example 9, even when PPO was not used, the content of the recycled resin was reduced, and the content of ASA was increased, fluidity, tensile strength, and heat resistance were poor. It was confirmed that Comparative Example 9 was not suitable for replacing conventional non-recycled resin compositions.

[0217] In addition, in the case of Comparative Example 7 including an excess of PPO, even though the content (about 15% by weight) of the recycled resin was about half of the content of examples, molding processability and colorability were poor. In addition, in the case of Comparative Example 8 in which the content of PPO was less than the range of the present invention, mechanical rigidity and heat resistance were poor. Meanwhile, referring to Comparative Example 10, the proportion of recycled resin in the total weight of the composition was similar to that of examples. However, the total content of the matrix resin and the ratio of the components constituting the matrix resin were out of the ranges of the present invention, and as a result, impact strength was greatly reduced.