Method of preparing ASA graft copolymer, method of preparing thermoplastic ASA resin composition including the same, and method of preparing ASA molded part

Patent metadata

Field	Value
Publication number	US-10487204-B2
Application number	US-201715781073-A
Country	US
Kind code	B2
Filing date	Oct 25, 2017
Priority date	Nov 2, 2016
Publication date	Nov 26, 2019
Grant date	Nov 26, 2019

Abstract

The present invention relates to a method of preparing an ASA graft copolymer, a method of preparing a thermoplastic ASA resin composition including the same, and a method of preparing an ASA molded part, and more particularly, to a method of preparing a multilayered ASA graft copolymer including a step of preparing seeds, cores, and shells. According to the method, since a multifunctional carboxylic acid having 20 or more carbon atoms or a salt thereof is introduced as an emulsifier, the content of the emulsifier remaining in a resin may be reduced, thereby providing an ASA resin having excellent thermal stability and appearance characteristics while the inherent physical properties thereof, such as impact resistance and weather resistance, are maintained.

First claim

The invention claimed is:

1. A method of preparing an ASA graft copolymer, comprising:
a) a seed preparation step, in which one or more monomers selected from an aromatic vinyl monomer, a vinyl cyan monomer, and an alkyl acrylate monomer are polymerized to prepare seeds;
b) a core preparation step, in which an alkyl acrylate monomer is added in the presence of the prepared seeds, and polymerization is performed to prepare cores; and
c) a shell preparation step, in which one or more monomers selected from an aromatic vinyl monomer and a vinyl cyan monomer and an emulsifier are added in the presence of the prepared cores, and graft polymerization is performed to prepare shells,
wherein the emulsifier contains a multifunctional carboxylic acid having 20 to 60 carbon atoms or a salt thereof, and an average size of the prepared shells is 80 to 150 nm (larger than an average size of the cores).

2. The method according to claim 1 , wherein two or three carboxyl groups are comprised in a structure of the multifunctional carboxylic acid.

3. The method according to claim 1 , wherein the multifunctional carboxylic acid having 20 to 60 carbon atoms or the salt thereof is contained in an amount of 30 to 100% by weight with respect to a total weight of the emulsifier.

4. The method according to claim 1 , wherein the emulsifier contains the multifunctional carboxylic acid having 20 to 60 carbon atoms or the salt thereof and a carboxylate having 10 to 20 carbon atoms.

5. The method according to claim 4 , wherein the emulsifier contains the multifunctional carboxylic acid having 20 to 60 carbon atoms or the salt thereof and the carboxylate having 10 to 20 carbon atoms in a weight ratio of 1:0.1 to 1:10.

6. The method according to claim 1 , wherein, in the seed preparation step, with respect to 100 parts by weight of total monomers used to prepare the copolymer, 4 to 20 parts by weight of one or more monomers selected from an aromatic vinyl monomer, a vinyl cyan monomer, and an alkyl acrylate are polymerized to prepare seeds.

7. The method according to claim 6 , wherein an average size of the seeds is 30 to 80 nm.

8. The method according to claim 1 , wherein, in the core preparation step, 30 to 60 parts by weight of an acrylate monomer and 0.01 to 1 part by weight of a crosslinking agent are added in the presence of the seeds, and polymerization is performed to prepare cores.

9. The method according to claim 8 , wherein the crosslinking agent comprises an acrylic crosslinking agent.

10. The method according to claim 8 , wherein an average size of the cores is 70 to 110 nm (larger than an average size of the seeds).

11. The method according to claim 1 , wherein, in the shell preparation step, 30 to 60 parts by weight of an aromatic vinyl monomer or a vinyl cyan monomer and 0.1 to 3 parts by weight of an emulsifier are added in the presence of the cores, and graft polymerization is performed to prepare shells.

12. A method of preparing a thermoplastic ASA resin composition, comprising a step of mixing and extruding 20 to 60% by weight of the ASA graft copolymer according to the method of claim 1 and 40 to 80% by weight of a vinyl cyan monomer-aromatic vinyl monomer copolymer.

13. The method according to claim 12 , wherein, when the mixing is performed, one or more additives selected from the group consisting of a flame retardant, a lubricant, an antibacterial agent, a release agent, a nucleating agent, a plasticizer, a heat stabilizer, an antioxidant, a light stabilizer, a pigment, a dye, and a compatibilizer are further mixed.

14. A method of preparing an ASA molded part, comprising a step of injecting the thermoplastic ASA resin composition prepared according to claim 12 .

15. The method according to claim 14 , wherein the ASA molded part is allowed to stand at 260° C. for 10 minutes and then injected, and, when chromaticity of the ASA molded part is measured using a spectrocolorimeter, a chromaticity change value (ΔE) between chromaticity values measured before and after standing at 260° C. is more than 0 and 4 or less.

16. The method according to claim 14 , wherein, in the step of injecting, an amount of generated gas is 1,000 ppm or less.

Assignees

• Lg Chemical Ltd

Inventors

• Ahn Bong Keun
• Hwang Yong Yeon
• Oh Hyun Taek
• Kim Min Jung
• Park Chun Ho
• Kang Eun Soo
• An Yong Hee
• Park Jang Won

Classifications

• C08K2003/162

  Calcium, strontium or barium halides, e.g. calcium, strontium or barium chloride · CPC title

• C08L51/003

  grafted on to macromolecular compounds obtained by reactions only involving unsaturated carbon-to-carbon bonds (C08L51/04, C08L51/06 take precedence) · CPC title

• C08K3/16

  Halogen-containing compounds · CPC title

• C08F265/06

  Polymerisation of acrylate or methacrylate esters on to polymers thereof · CPC title

• C08F2800/20

  as weight or mass percentages · CPC title