Method for preparing large-size diene-based rubber latex and acrylonitrile-butadiene-styrene graft copolymer comprising the same

Patent metadata

Field	Value
Publication number	US-10208151-B2
Application number	US-201515533631-A
Country	US
Kind code	B2
Filing date	Dec 10, 2015
Priority date	Dec 11, 2014
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

The present invention relates to a method for preparing a diene-based rubber latex having improved impact strength, gloss and flexibility, diene-based rubber latex prepared therefrom, and an acrylonitrile-butadiene-styrene graft copolymer having improved impact strength and production yield while having reduced rubber solid content ratio by comprising the same.

First claim

The invention claimed is:

1. A method for preparing a diene-based rubber latex comprising:
preparing a first solution by adding 50 to 75 parts by weight of a conjugated diene-based monomer, 1 part by weight to 3 parts by weight of an emulsifier, 0.1 parts by weight to 0.4 parts by weight of a polymerization initiator, 0.1 parts by weight to 3 parts by weight of an electrolyte, 0.1 parts by weight to 0.5 parts by weight of a molecular weight control agent and 65 parts by weight to 100 parts by weight of ion exchanged water, based on 100 parts by weight of the conjugated diene-based monomer, into a reactor while stirring, adding 0.05 part by weight to 0.3 part by weight of a cross-linking agent based on 100 parts by weight of the conjugated diene-based monomer, and then subjecting the first solution to a first polymerization (Step 1);
performing a second polymerization by further adding a balance of the conjugated diene-based monomer, 0 to 0.1 parts by weight of the emulsifier and 0 to 0.2 parts by weight of the cross-linking agent (Step 2); and
terminating the second polymerization when the polymerization conversion rate of the second polymerization is 90% or higher (Step 3), wherein the cross-linking agent is (propylene glycol)n diacrylate, in which n is 7 to 13.

2. The method for preparing the diene-based rubber latex of claim 1 , wherein the conjugated diene-based monomer is composed of a single material of a conjugated diene-based monomer.

3. The method for preparing the diene-based rubber latex of claim 1 , wherein the conjugated diene-based monomer is a mixture composed of:
80 wt % to 99 wt % of a conjugated diene-based co-monomer; and
1 wt % to 20 wt % of at least one monomer selected from the group consisting of an aromatic vinyl-based monomer and a vinyl cyanide-based monomer.

4. The method for preparing the diene-based rubber latex of claim 3 , wherein the aromatic vinyl-based monomer is one or more material selected from the group consisting of styrene, α-methyl styrene, m-methyl styrene, α-ethyl styrene p-methyl styrene and p-tert-butyl styrene.

5. The method for preparing the diene-based rubber latex of claim 3 , wherein the vinyl cyanide-based monomer is one or more material selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile and isopropyl acrylonitrile.

6. The method for preparing a diene-based rubber latex of claim 1 , wherein the conjugated diene-based monomer is one or more material selected from the group consisting of 1,3-butadiene, isoprene, chloroprene and piperylene.

7. The method for preparing diene-based rubber latex of claim 1 , wherein the cross-linking agent is (propylene glycol) 7 diacrylate or (propylene glycol) 13 diacrylate.

8. The method for preparing the diene-based rubber latex of claim 1 , wherein the emulsifier is a one or more materials selected from the group consisting of alkyl aryl sulfonate, alkali metal alkyl sulfonate, sulfonated alkyl ester, saponified fatty acid, alkali salt of oleic acid, alkali salt of stearic acid and alkali salt of rosin acid.

9. The method for preparing the diene-based rubber latex of claim 1 , wherein the polymerization initiator comprises a water-soluble polymerization initiator, a lipid-soluble polymerization initiator or an oxidation-reduction catalyst.

10. The method for preparing the diene-based rubber latex of claim 9 , wherein the water-soluble polymerization initiator is at least one persulfate selected from the group consisting of potassium persulfate, sodium persulfate and ammonium persulfate.

11. The method for preparing the diene-based rubber latex of claim 9 , wherein the lipid-soluble polymerization initiator is selected from the group consisting of cumene hydroperoxide, diisopropyl benzene hydroperoxide, azobis isobutyronitrile, tertiary butyl hydroperoxide, paramethane hydroperoxide and benzoylperoxide.

12. The method for preparing the diene-based rubber latex of claim 9 , wherein the oxidation-reduction catalyst is selected from the group consisting of sodium formaldehyde, sulfoxylate, sodium ethylenediamine tetraacetate, ferrous sulfate, dextrose, sodium pyrophosphate and sodium sulfite.

13. The method for preparing the diene-based rubber latex of claim 1 , wherein the electrolyte is a one or more materials selected from the group consisting of KCl, NaCl, KHCO 3 , NaHCO 3 , K 2 CO 3 , Na 2 CO 3 , KHSO 3 , NaHSO 3 , K 4 P 2 O 7 , Na 4 P 2 O 7 , K 3 PO 4 , Na 3 PO 4 , K 2 HPO 4 , and Na 2 HPO 4 .

14. The method for preparing the diene-based rubber latex of claim 1 , wherein the first polymerization is conducted at a temperature from 60° C. to 75° C.

15. The method for preparing the diene-based rubber latex of claim 1 , wherein the second polymerization is conducted at a temperature from 75° C. to 88° C.

16. The method for preparing the diene-based rubber latex of claim 1 , wherein the polymerization is terminated by lowering a temperature.

17. A diene-based rubber latex which is prepared by the method of claim 1 , and has an average particle diameter of 2,500 Å to 4,000 Å.

18. The diene-based rubber latex of claim 17 , wherein the diene-based rubber latex has a gel content of 60% to 80%.

19. The diene-based rubber latex of claim 17 , wherein the diene-based rubber latex has a swelling index of 15 to 25.

Assignees

• Lg Chemical Ltd

Inventors

• Suk Jae Min
• Kim Young Min
• Lee Jin Hyoung
• Han Su Jeong
• Kim Yoo Vin
• Jeong Young Hwan
• Chung Sun Haeng

Classifications

• C08F36/04 Primary

  conjugated · CPC title

• C08F2/22

  Emulsion polymerisation · CPC title

• C08F2/44

  Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers · CPC title

• C08F279/04 Primary

  Vinyl aromatic monomers and nitriles as the only monomers · CPC title

• Y10S526/911

  Emulsifying agents · CPC title