Heat-resistant styrene copolymer and styrene resin composition comprising the same

Patent metadata

Field	Value
Publication number	US-10047179-B2
Application number	US-201514909924-A
Country	US
Kind code	B2
Filing date	Apr 8, 2015
Priority date	Apr 25, 2014
Publication date	Aug 14, 2018
Grant date	Aug 14, 2018

Abstract

Provided is a styrene resin composition including α-methyl styrene, acrylonitrile and t-butyl methacrylate, and having an improved conversion rate while maintaining excellent mechanical and chemical properties, a styrene resin composition including the same, and a styrene resin molded product manufactured therefrom. Accordingly, the heat-resistant styrene copolymer is effective in improving a conversion rate without deformation and mechanical and chemical property decline of the material itself, and as a result, commercialization may be readily accomplished due to enhanced productivity. In addition, the styrene resin molded product manufactured from the styrene resin composition according to the present invention includes the heat-resistant styrene copolymer as a matrix copolymer, and therefore, has excellent impact strength, tensile strength, tensile elongation and flowability while having high heat resistance.

First claim

The invention claimed is:

1. A heat-resistant styrene copolymer comprising:
A) α-methyl styrene in an amount of 60 wt % to 78 wt %;
B) acrylonitrile in an amount of 20 wt % to 38 wt %; and
C) t-butyl methacrylate in an amount of 0.5 wt % to 7 wt %,
wherein the heat-resistant styrene copolymer has a glass transition temperature (Tg) in a range of 123° C. to 128° C. and a weight average molecular weight (Mw) of 87,000 to 91,000.

2. The heat-resistant styrene copolymer of claim 1 , wherein the C) t-butyl methacrylate is included in an amount of 1 wt % to 5 wt %.

3. The heat-resistant styrene copolymer of claim 1 , wherein the styrene copolymer has, when polymerized at a polymerization temperature of 105° C., a conversion rate of 40% to 60%.

4. A styrene resin composition comprising:
the a) heat-resistant styrene copolymer of claim 1 in 60 wt % to 80 wt %; and
a b) rubber copolymer in an amount of 20 wt % to 40 wt %.

5. The styrene resin composition of claim 4 , wherein the b) rubber copolymer is at least one selected from the group consisting of an acrylonitrile-butadiene-styrene graft copolymer having a core-shell structure (ABS) and an acrylate-styrene-acrylonitrile graft copolymer having a core-shell structure (ASA).

6. The styrene resin composition of claim 4 , wherein the b) rubber copolymer has an average diameter of 250 nm to 500 nm.

7. The styrene resin composition of claim 5 , wherein the acrylonitrile-butadiene-styrene graft copolymer having a core-shell structure (ABS) comprises a diene copolymer core in an amount of 50 wt % to 80 wt %; and a shell including a styrene monomer and an acrylonitrile monomer grafted on the core in an amount of 20 wt % to 50 wt %, wherein a thickness ratio of the core to the shell is from 4:6 to 8:2.

8. The styrene resin composition of claim 7 , wherein the shell comprises the styrene monomer and the acrylonitrile monomer in a weight ratio of 7:3 to 8:2.

9. The styrene resin composition of claim 7 , wherein the diene copolymer is derived from one or more of conjugated diene monomers selected from the group consisting of 1,3-butadiene, isoprene, chloroprene and piperylene.

10. The styrene resin composition of claim 5 , wherein the acrylate-styrene-acrylonitrile graft copolymer having a core-shell structure (ASA) comprises an acrylate polymer core in 40 wt % to 60 wt %; and a shell including a styrene monomer and an acrylonitrile monomer grafted on the core in 40 wt % to 60 wt %, wherein a thickness ratio of the core to the shell is from 4:6 to 8:2.

11. The styrene resin composition of claim 10 , wherein the shell includes the styrene monomer and the acrylonitrile monomer in a weight ratio of 7:3 to 8:2.

12. The styrene resin composition of claim 10 , wherein the acrylate polymer is derived from butyl acrylate, ethylhexyl acrylate or a mixture thereof.

13. The styrene resin composition of claim 7 , wherein the styrene monomer is at least one selected from the group consisting of styrene, α-methyl styrene, α-ethyl styrene, p-ethyl styrene, vinyl toluene and a derivative thereof.

14. The styrene resin composition of claim 7 , wherein the acrylonitrile monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile and a derivative thereof.

15. The styrene resin composition of claim 4 , wherein the styrene resin composition further comprises one or more additives selected from the group consisting of a thermal stabilizer, a lubricant, an antioxidant, a photostabilizer, a flame retardant, an antistatic agent, a coloring agent, a filler and a UV stabilizer.

16. A styrene resin molded product manufactured from the styrene resin composition of claim 4 , which has an impact strength of 20 J/m to 25 J/m measured in accordance with ASTM D256 when having a thickness of ¼″, and has tensile elongation of 28% to 40% measured in accordance with ASTM D638 under a rate condition of 5 cm/min when having a thickness of ⅛″.

17. The styrene resin composition of claim 10 , wherein the styrene monomer is at least one selected from the group consisting of styrene, α-methyl styrene, α-ethyl styrene, p-ethyl styrene, vinyl toluene and a derivative thereof.

18. The styrene resin composition of claim 10 , wherein the acrylonitrile monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile and a derivative thereof.

19. The heat resistant styrene copolymer of claim 1 , wherein the A) α-methyl styrene, the B) acrylonitrile and the C) t-butyl methacrylate have a weight ratio of 70 to 72:23 to 29.5:0.5 to 7.

Assignees

• Lg Chemical Ltd

Inventors

• Kang Byoung Il
• Han Chang Hun
• Seo Jae Bum
• Choi Eun Jung
• Sung Da Eun

Classifications

• C08L2201/08

  Stabilised against heat, light or radiation or oxydation · CPC title

• C08L25/16

  Homopolymers or copolymers of alkyl-substituted styrenes · CPC title

• C08L55/02

  ABS [Acrylonitrile-Butadiene-Styrene] polymers · CPC title

• C08L51/04

  grafted on to rubbers · CPC title

• C08F212/10 Primary

  with nitriles · CPC title