THERMOPLASTIC RESIN COMPOSITION

Abstract

Provided is a thermoplastic resin composition which includes: a base resin including, in a weight ratio of 70:30 to 90:10, a first copolymer formed by graft polymerization of a diene-based rubber polymer having an average particle diameter of 50 to 200 nm with a first monomer mixture including an alkyl(meth)acrylate-based monomer and an aromatic vinyl-based monomer and a second copolymer which is a copolymer of a second monomer mixture including an alkyl(meth)acrylate-based monomer and an aromatic vinyl-based monomer; and a plasticizer.

Claims

1. A thermoplastic resin composition comprising: a base resin including, in a weight ratio of 70:30 to 90:10, a first copolymer formed by graft polymerization of a diene-based rubber polymer having an average particle diameter of 50 to 200 nm with a first monomer mixture including an alkyl(meth)acrylate-based monomer and an aromatic vinyl-based monomer and a second copolymer which is a copolymer of a second monomer mixture including an alkyl(meth)acrylate-based monomer and an aromatic vinyl-based monomer; and a plasticizer.

2. The thermoplastic resin composition of claim 1, wherein the base resin is included in an amount of 100 parts by weight, and the plasticizer is included in an amount of 4 to 10 parts by weight.

3. The thermoplastic resin composition of claim 1, wherein the plasticizer is a polyester-based plasticizer.

4. The thermoplastic resin composition of claim 1, wherein the plasticizer has a viscosity of 1,500 to 5,000 cps.

5. The thermoplastic resin composition of claim 1, wherein the plasticizer is one or more selected from the group consisting of: polydi(2-ethylhexyl)glycoladipate; hexanedioic acid, polymer with 1,3-butanediol, 2-ethylhexyl ester; hexanedioic acid, polymer with 1,3-butanediol and 1,2-propanediol, 2-ethylhexyl ester; and hexanedioic acid, polymer with 2,2-dimethyl-1,3-propanediol and 1,2-propanediol, isononyl ester.

6. The thermoplastic resin composition of claim 1, wherein the plasticizer has a refractive index of 1.45 to 1.6.

7. The thermoplastic resin composition of claim 1, wherein the refractive indices of the first copolymer and the second copolymer differ by 0.01 or less.

8. The thermoplastic resin composition of claim 1, wherein each of the first and second monomer mixtures further includes a vinyl cyanide-based monomer.

9. A thermoplastic resin molded article made of the thermoplastic resin composition according to claim 1, wherein the thermoplastic resin molded article has a haze of 2.0% or less, a flexural strength of 280 to 420 kg/cm.sup.2, and a flexural modulus of 11,000 to 13,500 kg/cm.sup.2.

Description

PREPARATION EXAMPLE 1

[0061] 50 parts by weight (based on solid content) of butadiene rubber polymer latex (average particle diameter: 120 nm, gel content: 90%), 50 parts by weight of ion exchanged water, 8.8 parts by weight of methyl methacrylate, 3 parts by weight of styrene, 0.8 parts by weight of acrylonitrile, 0.1 parts by weight of divinylbenzene as a crosslinking agent, 0.2 parts by weight of cumene hydroperoxide as an initiator, and 0.5 parts by weight of sodium dodecylbenzenesulfonate as an emulsifier were batch-added to a nitrogen-substituted reactor and mixed for 5 hours. Subsequently, polymerization was performed while continuously adding, to the reactor, 26.2 parts by weight of methyl methacrylate, 9 parts by weight of styrene, 2.2 parts by weight of acrylonitrile, 0.5 parts by weight of t-dodecyl mercaptan as a molecular weight controlling agent, 0.05 parts by weight of disodium ethylenediamine tetraacetate, 0.1 parts by weight of sodium formaldehyde sulfoxylate, and 0.001 parts by weight of ferrous sulfate as activators, and 0.1 parts by weight of cumene hydroperoxide as an initiator at 70° C. and a constant rate for 5 hours. After the continuous addition was terminated, the temperature was raised to 80° C., aging was performed for an hour, and the polymerization was then terminated to obtain a graft copolymer latex. The graft copolymer latex was coagulated by adding 2 parts by weight of magnesium sulfate as a coagulant, aged, dehydrated, and dried to obtain a graft copolymer powder. In this case, the graft copolymer powder had a refractive index of 1.516 and a degree of grafting of 55%.

PREPARAION EXAMPLE 2

[0062] 50 parts by weight (based on solid content) of butadiene rubber polymer latex (average particle diameter: 300 nm, gel content: 70%), 50 parts by weight of ion exchanged water, 8.8 parts by weight of methyl methacrylate, 3 parts by weight of styrene, 0.8 parts by weight of acrylonitrile, 0.1 parts by weight of divinylbenzene as a crosslinking agent, 0.2 parts by weight of cumene hydroperoxide as an initiator, and 0.5 parts by weight of sodium dodecylbenzenesulfonate as an emulsifier were added to a nitrogen-substituted reactor and mixed for 3 hours. Subsequently, polymerization was performed while continuously adding, to the reactor, 26.2 parts by weight of methyl methacrylate, 9 parts by weight of styrene, 2.2 parts by weight of acrylonitrile, 0.5 parts by weight of t-dodecyl mercaptan as a molecular weight controlling agent, 0.05 parts by weight of disodium ethylenediamine tetraacetate, 0.1 parts by weight of sodium formaldehyde sulfoxylate, and 0.001 parts by weight of ferrous sulfate as activators, and 0.1 parts by weight of cumene hydroperoxide as an initiator at 70° C. and a constant rate for 5 hours. After the continuous addition was terminated, the temperature was raised to 80° C., aging was performed for an hour, and the polymerization was then terminated to obtain a graft copolymer latex. The graft copolymer latex was coagulated by adding 2 parts by weight of magnesium sulfate as a coagulant, aged, dehydrated, and dried to obtain a graft copolymer powder. In this case, the graft copolymer powder had a refractive index of 1.516 and a degree of grafting of 45%.

PREPARATION EXAMPLE 3

[0063] Polymerization was performed while continuously adding, to a nitrogen-substituted reactor, 70.4 parts by weight of methyl methacrylate, 24.6 parts by weight of styrene, 5 parts by weight of acrylonitrile, 30 parts by weight of toluene, and 0.15 parts by weight of t-dodecyl mercaptan as a molecular weight controlling agent at 148° C. and a constant rate for 3 hours, thereby obtaining a copolymer. The copolymer was heated in a preheating bath, and unreacted monomers and a solvent were removed in a volatilization tank. Subsequently, the copolymer, from which unreacted monomers and the like had been removed, was input into a polymer transfer pump extruder and extruded at 210° C. to obtain a pellet-type copolymer. The resulting copolymer had a weight-average molecular weight of 90,000 g/mol and a refractive index of 1.516.

EXAMPLES AND COMPARATIVE EXAMPLES

[0064] The specifications of components used in Examples and Comparative Examples are as follows.

[0065] (A) Graft copolymer

[0066] (A-1): The graft copolymer prepared in Preparation Example 1 was used.

[0067] (A-2): The graft copolymer prepared in Preparation Example 2 was used.

[0068] (A-3): Methyl methacrylate/acrylonitrile/butadiene/styrene graft copolymer: TR557-NP commercially available from LG Chem Ltd. (refractive index: 1.516, average particle diameter of butadiene rubber polymer: 300 nm) was used.

[0069] (B) Non-graft copolymer: The copolymer prepared in Preparation Example 3 was used.

[0070] (C) Plasticizer

[0071] (C-1): SONGCIZER™ P-2600 commercially available from Songwon Industrial Co., Ltd (viscosity: 2,700 to 3,500 cps, refractive index: 1.462 to 1.468, polydi(2-ethylhexyl)glycoladipate) was used.

[0072] (C-2): SONGCIZER™ P-3000 commercially available from Songwon Industrial Co., Ltd (viscosity: 2,000 to 3,200 cps, refractive index: 1.462 to 1.468, polydi(2-ethylhexyl)glycoladipate) was used.

[0073] (C-3): Palamoll® 652 commercially available from BASF Corporation (viscosity: 2,000 cps, refractive index: 1.465, hexanedioic acid, polymer with 2,2-dimethyl-1,3-propanediol and 1,2-propanediol, isononyl ester) was used.

[0074] (D) Styrene/butadiene copolymer: KR-03 commercially available from Chevron (refractive index: 1.571) was used.

[0075] The above-described components were mixed in contents shown in Table 1 to Table 5 and stirred to prepare thermoplastic resin compositions.

Experimental Example 1

[0076] Each of the thermoplastic resin compositions of Examples and Comparative Examples was input into a twin-screw extruder set at 230° C. and then extruded to prepare a pellet. The melt flow index of the pellet was measured by a method described below, and results thereof are shown in Table 1 to Table 5.

[0077] (1) Melt flow index (g/10 min): measured under conditions of 220° C. and 10 kg in accordance with ASTM D1238.

Experimental Example 2

[0078] The pellet prepared in Experimental Example 1 was injection-molded at 230° C. to prepare a specimen. Physical properties of the specimen were measured by methods described below, and results thereof are shown in Table 1 to Table 5.

[0079] (2) Haze (%): measured in accordance with ASTM D1003.

[0080] (3) Flexural strength (kg/cm.sup.2): measured in accordance with ASTM D790.

[0081] (4) Flexural modulus (kg/cm.sup.2): measured in accordance with ASTM D790.

[0082] (5) Hardness: measured in accordance with ASTM D785 (R-scale).

[0083] (6) Migration: evaluated by placing the specimen on oil paper in a 70° C. oven, applying a weight of 10 kg onto the specimen, storing it for a week, and then observing the change of the oil paper. When migrated, the plasticizer wets the oil paper so as to discolor the oil paper, and thus the discoloration means that the oil paper was stained with the plasticizer due to the migration of the plasticizer. Therefore, no discoloration was indicated as “OK”, and discoloration was indicated as “NG”.

TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Comparative Classification Example 1 Example 2 Example 1 Example 2 Example 3 Example 3 Example 4 (A) Graft (A-1) 50 65 70 85 90 95 0 copolymer (A-2) 0 0 0 0 0 0 70 (parts by (A-3) 0 0 0 0 0 0 0 weight) (B) Non-graft 50 35 30 15 10 5 30 copolymer (parts by weight) (C) Plasticizer (C-1 5 5 5 5 5 5 5 (parts by (C-2) 0 0 0 0 0 0 0 weight) (C-3) 0 0 0 0 0 0 0 (D) Styrene/butadiene 0 0 0 0 0 0 0 copolymer (parts by weight) {circle around (1)} Melt flow 19.2 15.0 13.8 11.0 10.1 4.4 15.7 index {circle around (2)} Haze 0.9 1.0 1.0 1.4 1.5 2.2 3.8 {circle around (3)} Flexural 570 480 377 320 304 300 360 strength {circle around (4)} Flexural 16,500 16,000 12,300 12,000 11,800 11,150 10,400 modulus {circle around (5)} Hardness 95 90 83 80 76 68 77 {circle around (6)} Migration OK OK OK OK OK OK OK

TABLE-US-00002 TABLE 2 Exam- Exam- Exam- Exam- Classification ple 4 ple 5 ple 6 ple 7 (A) Graft (A-1) 85 85 85 85 copolymer (A-2) 0 0 0 0 (parts by (A-3) 0 0 0 0 weight) (B) Non-graft copolymer 15 15 15 15 (parts by weight) (C) Plasticizer (C-1) 4 6 9 10 (parts by (C-2) 0 0 0 0 weight) (C-3) 0 0 0 0 (D) Styrene/butadiene 0 0 0 0 copolymer (parts by weight) {circle around (1)} Melt flow index 7.7 11.9 14.5 15.0 {circle around (2)} Haze 1.4 1.3 2.0 2.0 {circle around (3)} Flexural strength 310 316 310 311 {circle around (4)} Flexural modulus 12,500 12,000 11,900 11,900 {circle around (5)} Hardness 76 79 77 77 {circle around (6)} Migration OK OK OK OK

TABLE-US-00003 TABLE 3 Comparative Comparative Classification Example 5 Example 8 Example 9 Example 10 Example 6 (A) Graft (A-1) 65 70 75 90 95 copolymer (A-2) 0 0 0 0 0 (parts by (A-3) 0 0 0 0 0 weight) (B) Non-graft copolymer 35 30 25 10 5 (parts by weight) (C) Plasticizer (C-1) 0 0 0 0 0 (parts by (C-2) 6 5 9 7 9 weight) (C-3) 0 0 0 0 0 (D) Styrene/butadiene 0 0 0 0 0 copolymer (parts by weight) {circle around (1)} Melt flow index 15.3 13.0 16.0 10.3 8.0 {circle around (2)} Haze 1.1 1.2 1.8 1.5 2.5 {circle around (3)} Flexural strength 460 370 342 305 290 {circle around (4)} Flexural modulus 16,000 12,400 12,100 11,800 11,200 {circle around (5)} Hardness 90 81 80 76 68 {circle around (6)} Migration OK OK OK OK OK

TABLE-US-00004 TABLE 4 Exam- Exam- Exam- Classification ple 11 ple 12 ple 13 (A) Graft (A-1) 70 70 80 copolymer (A-2) 0 0 0 (parts by (A-3) 0 0 0 weight) (B) Non-graft copolymer 30 30 20 (parts by weight) (C) Plasticizer (C-1) 0 0 0 (parts by (C-2) 0 0 0 weight) (C-3) 4 5 9 (D) Styrene/butadiene 0 0 0 copolymer (parts by weight) {circle around (1)} Melt flow index 8.5 12.6 15.2 {circle around (2)} Haze 1.0 1.1 1.9 {circle around (3)} Flexural strength 370 366 330 {circle around (4)} Flexural modulus 12,400 12,300 12,100 {circle around (5)} Hardness 84 84 79 {circle around (6)} Migration OK OK OK

TABLE-US-00005 TABLE 5 Comparative Comparative Classification Example 7 Example 8 (A) Graft (A-1) 0 0 copolymer (A-2) 0 0 (parts by (A-3) 100 60 weight) (B) Non-graft copolymer 0 0 (parts by weight) (C) Plasticizer (C-1) 0 0 (parts by (C-2) 0 0 weight) (C-3) 0 0 (D) Styrene/butadiene 0 40 copolymer (parts by weight) {circle around (1)} Melt flow index 23.0 53.3 {circle around (2)} Haze 2.0 Opaque {circle around (3)} Flexural strength 720 515 {circle around (4)} Flexural modulus 23,000 17,793 {circle around (5)} Hardness 104 36 {circle around (6)} Migration OK OK

[0084] Referring to Table 1, Examples 1 to 3 including appropriate amounts of a graft copolymer and a non-graft copolymer were excellent in all of a melt flow index, haze, flexural strength, flexural modulus, hardness, and migration and thus suitable for artificial nails. On the other hand, Comparative Examples 1 and 2 including a small amount of a graft copolymer exhibited higher flexural strength, higher flexural modulus, and higher hardness compared to Examples 1 to 3 and thus were not suitable for artificial nails. In addition, Comparative Example 3 including an excessive amount of a graft copolymer exhibited a lower melt flow index and higher haze compared to Examples 1 to 3, resulting in degraded processability, and thus was not suitable for artificial nails. Comparative Example 4 including a diene-based rubber polymer having a large average particle diameter exhibited high haze and low flexural modulus and thus was not suitable for artificial nails. Referring to Table 2, it can be seen that as the plasticizer content is increased within the appropriate plasticizer content range, haze is maintained, and a melt flow index is increased. In particular, it can be seen that Examples 5 to 7 exhibited melt flow indices of 10 g/10 min or more, resulting in excellent processability, as compared to Example 4.

[0085] Referring to Table 3, Examples 8 to 10 including optimal amounts of a graft copolymer and a non-graft copolymer were excellent in all of a melt flow index, haze, flexural strength, flexural modulus, hardness, and migration and thus suitable for artificial nails. On the other hand, Comparative Example 5 including a small amount of a graft copolymer exhibited relatively high flexural strength, high flexural modulus, and high hardness and thus was not suitable for artificial nails. Comparative Example 6 including an excessive amount of a graft copolymer exhibited a relatively low melt flow index, resulting in degraded processability, and also exhibited relatively high haze and low flexural modulus, and thus was not suitable for artificial nails.

[0086] Referring to Table 4, Examples 11 to 13 satisfying the appropriate plasticizer content range were excellent in all of haze, flexural strength, flexural modulus, hardness, and migration and thus suitable for artificial nails. In particular, it can be seen that Examples 12 and 13 exhibited melt flow indices of 10 g/10 min or more, resulting in excellent processability, as compared to Example 11.

[0087] Referring to Table 5, Comparative Example 7 consisting of only a graft copolymer exhibited relatively high flexural strength, high flexural modulus, and high hardness and thus was not suitable for artificial nails, and Comparative Example 8 consisting of a graft copolymer and a styrene/butadiene copolymer was opaque and exhibited relatively high flexural strength and high flexural modulus and thus was not suitable for artificial nails.