Production method for rubber-reinforced thermoplastic resin

• US 9,932,472 B2
• Filed: 07/22/2014
• Issued: 04/03/2018
• Est. Priority Date: 08/02/2013
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Ahn, Bong Keun, Yoo, Keun Hoon, Kim, Dae Young
• Primary Examiner(s): Mullis, Jeffrey C
• Application Number:
  US14/893,898
• Publication Number:
  US 20160137830A1
• Time in Patent Office: 1,351 Days
• CPC Class Codes: C08F 220/62 Monocarboxylic acids having ten or more carbon atoms; Derivatives thereof copolymers of drying oils C08F242/00
• CPC Class Codes: C08F 236/06 Butadiene
• CPC Class Codes: C08F 279/04 Vinyl aromatic monomers and nitriles as the only monomers
• CPC Class Codes: C08L 51/04 grafted on to rubbers

Abstract

Disclosed is a method of preparing a rubber-reinforced thermoplastic resin. According to the present invention, a graft copolymer comprising a large-particle-size rubber polymer obtained by welding polymerization-heat-control-type small particles and a reactive emulsifier or a mixed emulsifier comprising a reactive emulsifier and a non-reactive emulsifier is prepared, and a rubber-reinforced thermoplastic resin comprising the same may have enhanced mechanical properties, thermal stability, surface visibility and gloss.

Claims

1. A method of preparing a rubber-reinforced thermoplastic resin, the method comprising:

preparing a small particle size rubber polymer using a polymerization process in which temperature deviation is 4°

C. or less, the small particle size rubber polymerization process including polymerizing a conjugated diene monomer;

preparing a rubber polymer having a large particle size using the small particle size rubber polymer;

preparing an acrylonitrile-styrene-butadiene-based graft copolymer from the rubber polymer having the large particle size;

dehydrating the acrylonitrile-styrene-butadiene-based graft copolymer to a moisture content of 5 to 15%; and

mixing the dehydrated graft copolymer and a matrix resin,

wherein the preparation process of the small-particle-size rubber polymer comprises (a) inputting batchwise a first composition containing 5 to 80 parts by weight of the conjugated diene monomer and initiating the reaction at 50 to 70°

C.; and

(b) at a time point of 0 to 8 hours from the reaction initiation point, performing emulsion polymerization at 70 to 80°

C. while continuously inputting a second composition containing 95 to 20 parts by weight of a conjugated diene monomer for 4 to 10 hours, and after commencement of the continuous addition, controlling temperature deviation to be 4°

C. or less during step (b).

2. The method according to claim 1, wherein the small-particle-size rubber polymer is prepared by emulsion-polymerizing at polymerization temperature of 50 to 80°

C. for 5 to 13 hours.

3. The method according to claim 1, wherein the first composition comprises 1 to 4 parts by weight of a reactive emulsifier, 0.1 to 3 parts by weight of a polymerization initiator, 0.1 to 1 parts by weight of a molecular weight controller, 0.1 to 3 parts by weight of an electrolyte and 100 to 150 parts by weight of ion deionized water, based on 100 parts by weight of the conjugated diene monomer.

4. The method according to claim 1, wherein the second composition comprises 0.01 to 1 parts by weight of a molecular weight controller based on 100 parts by weight of the total conjugated diene monomer.

5. The method according to claim 1, wherein the small-particle-size rubber polymer has an average particle size of 500 to 2000 Å

, a gel content of 90 to 99 wt % and glass transition temperature (Tg) of 0°

C. or less.

6. The method according to claim 1, wherein, in the preparing into the large particle size, a rubber polymer having an average particle size of 2500 to 4000 Å

is obtained by welding the small-particle-size rubber polymer with 0.1 to 5 parts by weight of one or more acidic ingredients selected from acetic acid and phosphoric acid based on 100 parts by weight of the small-particle-size rubber polymer.

7. The method according to claim 1, wherein the acrylonitrile-styrene-butadiene-based graft copolymer is prepared by polymerizing at 45 to 80°

C. for three to six hours while continuously inputting to 0.001 to 0.5 parts by weight of a reactive emulsifier, or a mixed emulsifier comprising 0.001 to 0.3 parts by weight of a reactive emulsifier and 0.1 to 0.7 parts by weight of a non-reactive emulsifier;

0.1 to 0.5 parts by weight of a molecular weight controller; and

0.1 to 0.5 parts by weight of a polymerization initiator to 100 parts by weight of a mixture that comprises 50 to 70 wt % of the rubber polymer prepared into a large particle size; and

50 to 30 wt % of a mixture comprising a styrene based monomer and an acrylonitrile based monomer, in an emulsion state, wherein the parts are based on the weight of styrene based monomer and acrylonitrile based monomer being 100 parts.

8. The method according to claim 1, wherein the acrylonitrile-styrene-butadiene-based graft copolymer is prepared in a solution with a coagulated solid content of the graft copolymer of 0.001 to 0.07 wt % of a total content of the rubber polymer and monomers in the solution.

9. The method according to claim 1, wherein the dehydrating is carried out after coagulating the graft copolymer with one coagulant or more selected from MgSO₄, CaCl₂, Al₂(SO₄)₃, sulfuric acid, phosphoric acid and hydrochloric acid.

10. The method according to claim 3, wherein the reactive emulsifier is one or more selected from sulfoethyl methacrylate, 2-acrylamido-2-methylpropane sulfonic acid, sodium styrene sulfonate, sodium dodecyl allyl sulfosuccinate, a copolymer of styrene and sodium dodecyl allyl sulfosuccinate, polyoxyethylene alkylphenyl ether ammonium sulfate, alkenyl C16-18 succinic acid di-potassium salt and sodium methallyl sulfonate.

11. The method according to claim 3, wherein the first composition further comprises a non-reactive emulsifier including one or more selected from alkylaryl sulfonate, methyl alkyl sulfate, sulfonated alkyl ester, fatty-acid soap and rosin-acid alkali salt.

12. The method according to claim 1, wherein the graft copolymer and the matrix resin are mixed by mixing, melting and kneading 20 to 40 parts by weight of the dehydrated graft copolymer with 80 to 60 parts by weight of one or more matrix resin selected from styrene-acrylonitrile based copolymer, polyvinylchloride and polycarbonate, based on 100 parts per weight of a total mixture.

13. The method according to claim 12, wherein the styrene-acrylonitrile based copolymer is an acrylonitrile-styrene copolymer comprising 10 to 35 wt % of acrylonitrile and 65 to 90 wt % of styrene;

an acrylonitrile-styrene-alpha-methylstyrene tercopolymer comprising 25 to 39 wt % of acrylonitrile, 60 to 80 wt % of alpha-methylstyrene and 1 to 20 wt % of styrene;

or a mixture thereof.

14. The method according to claim 7, wherein the reactive emulsifier is one or more selected from sulfoethyl methacrylate, 2-acrylamido-2-methylpropane sulfonic acid, sodium styrene sulfonate, sodium dodecyl allyl sulfosuccinate, a copolymer of styrene and sodium dodecyl allyl sulfosuccinate, polyoxyethylene alkylphenyl ether ammonium sulfate, alkenyl C16-18 succinic acid di-potassium salt and sodium methallyl sulfonate.

15. The method according to claim 7, wherein the non-reactive emulsifier is one or more selected from alkylaryl sulfonate, methyl alkyl sulfate, sulfonated alkyl ester, fatty-acid soap and rosin-acid alkali salt.