Thermoplastic resin composition and thermoplastic resin molded article prepared therefrom

Patent metadata

Field	Value
Publication number	US-9834645-B2
Application number	US-201514911455-A
Country	US
Kind code	B2
Filing date	Jul 23, 2015
Priority date	Sep 16, 2014
Publication date	Dec 5, 2017
Grant date	Dec 5, 2017

Abstract

Provided are a thermoplastic resin composition having high environmental stress crack resistance (ESCR) as well as excellent impact resistance and transparency and a thermoplastic resin molded article prepared therefrom. The thermoplastic resin composition includes a graft copolymer (A), in which a (meth)acrylic acid ester, a vinyl cyan-based compound, and an aromatic vinyl compound are graft polymerized with a conjugated diene-based rubber latex; and a copolymer (B) of a (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound in a weight ratio of 35:65 to 70:30. A difference in refractive indices of the graft copolymer (A) and the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound is less than 0.003 when irradiated with light having a wavelength of 450 nm to 680 nm, and a melt index is 4.0 g/10 min or less when the melt index is measured in accordance with ASTM D1238.

First claim

The invention claimed is:

1. A thermoplastic resin composition comprising a graft copolymer (A), in which a (meth)acrylic acid ester, a vinyl cyan-based compound, and an aromatic vinyl compound are graft polymerized with a conjugated diene-based rubber latex; and a copolymer (B) of a (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound in a weight ratio of 35:65 to 70:30,
wherein solids of the conjugated diene-based rubber latex are included in an amount of 20 wt % to 35 wt % based on a total weight of the thermoplastic resin composition,
wherein a difference in refractive indices of the graft copolymer (A) and the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound is less than 0.003 when irradiated with light having a wavelength of 450 nm to 680 nm, and
wherein a melt index is 4.0 g/10 min or less when the melt index is measured at a temperature of 220° C. and under a load of 10 kg in accordance with ASTM D1238.

2. The thermoplastic resin composition of claim 1 , wherein the conjugated diene-based rubber latex is a conjugated diene-based compound homopolymer, or a copolymer of a conjugated diene-based compound and an ethylene-based unsaturated compound.

3. The thermoplastic resin composition of claim 1 , wherein the (meth)acrylic acid esters in the graft copolymer (A) and the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound, each independently comprise one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, and 2-ethylhexyl methacrylate, or a mixture of two or more thereof.

4. The thermoplastic resin composition of claim 1 , wherein the aromatic vinyl compounds in the graft copolymer (A) and the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound, each independently comprise one selected from the group consisting of styrene, α-methyl styrene, vinyl toluene, alkyl styrene substituted with a C 1-3 alkyl group, and halogen-substituted styrene, or a mixture of two or more thereof.

5. The thermoplastic resin composition of claim 1 , wherein the vinyl cyan-based compounds in the graft copolymer (A) and the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound, each independently comprise one selected from the group consisting of acrylonitrile, methacrylonitrile, and derivatives thereof, or a mixture of two or more thereof.

6. The thermoplastic resin composition of claim 1 , wherein the graft copolymer (A) has a core-shell structure comprising 45 wt % to 75 wt % of a conjugated diene-based rubber latex core; and 25 wt % to 55 wt % of a shell including the (meth)acrylic acid ester, the vinyl cyan-based compound, and the aromatic vinyl compound which are grafted onto the core.

7. The thermoplastic resin composition of claim 6 , wherein a difference in refractive indices of the conjugated diene-based rubber latex core and the shell is less than 0.003.

8. The thermoplastic resin composition of claim 6 , wherein the conjugated diene-based rubber latex core a gel content of 70 wt % to 95 wt %, and a swelling index of 12 to 30.

9. The thermoplastic resin composition of claim 1 , wherein the graft copolymer (A) is prepared by graft polymerization of the (meth)acrylic acid ester, the vinyl cyan-based compound, and the aromatic vinyl compound with the conjugated diene-based rubber latex using a chain transfer agent,
wherein the (meth)acrylic acid ester, the vinyl cyan-based compound, and the aromatic vinyl compound are used in a weight ratio of 20:2:8 to 40:10:15, and
the chain transfer agent is used in an amount of 0.05 part by weight to 0.4 part by weight based on 100 parts by weight of a total sum of the solids of the conjugated diene-based rubber latex and monomers grafted with the conjugated diene-based rubber latex.

10. The thermoplastic resin composition of claim 9 , wherein the chain transfer agent comprises one selected from the group consisting of n-butylmercaptan, n-octylmercaptan, n-dodecylmercaptan, and t-dodecylmercaptan, or a mixture of two or more thereof.

11. The thermoplastic resin composition of claim 1 , wherein a solid coagulum content included in the graft copolymer (A) is less than 0.5 wt %.

12. The thermoplastic resin composition of claim 1 , wherein the graft copolymer (A) includes a methyl methacrylate-acrylonitrile-butadiene-styrene copolymer.

13. The thermoplastic resin composition of claim 1 , wherein the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound comprises:
55 wt % to 70 wt % of the (meth)acrylic acid ester;
20 wt % to 30 wt % of the aromatic vinyl compound; and
2 wt % to 10 wt % of the vinyl cyan-based compound.

14. The thermoplastic resin composition of claim 1 , wherein the copolymer (B) of the (meth)acrylic acid ester-aromatic vinyl compound-vinyl cyan-based compound is a methyl methacrylate-styrene-acrylonitrile copolymer.

15. The thermoplastic resin composition of claim 1 , wherein a haze measured in accordance with DIN 75201 method A is 2.5% or less.

16. A thermoplastic resin composition comprising a graft copolymer, in which methyl methacrylate, acrylonitrile, and styrene are graft polymerized with a conjugated diene-based rubber latex; and a methyl methacrylate-styrene-acrylonitrile copolymer in a weight ratio of 35:65 to 70:30,
wherein solids of the conjugated diene-based rubber latex are included in an amount of 20 wt % to 35 wt % based on a total weight of the thermoplastic resin composition,
a difference in refractive indices of the graft copolymer and the methyl methacrylate-styrene-acrylonitrile copolymer is less than 0.003 when irradiated with light having a wavelength of 450 nm to 680 nm,
the graft copolymer is prepared by graft polymerization of the methyl methacrylate, the acrylonitrile, and the styrene with the conjugated diene-based rubber latex using a chain transfer agent,
the methyl methacrylate, the acrylonitrile, and the styrene are used in a weight ratio of 20:2:8 to 40:10:15, and
the chain transfer agent is used in an amount of 0.05 part by weight to 0.4 part by weight based on 100 parts by weight of a total sum of the conjugated diene-based rubber latex and monomers grafted with the conjugated diene-based rubber latex.

17. A thermoplastic resin molded article prepared from the thermoplastic resin composition of claim 1 .

18. The thermoplastic resin composition of claim 1 , wherein the graft copolymer (A) and the copolymer (B) are present in a weight ratio of 48:52 to 58:42.

19. The thermoplastic resin composition of claim 16 , wherein the graft copolymer (A) and the copolymer (B) are present in a weight ratio of 48:52 to 58:42.

Assignees

• Lg Chemical Ltd

Inventors

• Yoo Keun Hoon
• Choi Jeong Su
• Lee Won Seok
• Jang Seok Goo
• Lee Roo Da
• Park Sang Hoo
• Kim Ho Hoon

Classifications

• C08L51/04

  grafted on to rubbers · CPC title

• C08L33/12

  Homopolymers or copolymers of methyl methacrylate · CPC title

• C08G81/027

  containing polyester or polycarbonate sequences · CPC title

• C08J5/00

  Manufacture of articles or shaped materials containing macromolecular substances (manufacture of semi-permeable membranes B01D67/00 - B01D71/00) · CPC title

• C08G81/024 Primary

  Block or graft polymers containing sequences of polymers of C08C or C08F and of polymers of C08G · CPC title