Method for producing synthetic polyisoprene latex

Patent metadata

Field	Value
Publication number	US-11084918-B2
Application number	US-201716346857-A
Country	US
Kind code	B2
Filing date	Nov 2, 2017
Priority date	Nov 15, 2016
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

A method for producing a synthetic polyisoprene latex, including a step of mixing a latex of synthetic polyisoprene (A) synthesized by use of a Ziegler type catalyst and a latex of synthetic polyisoprene (B) synthesized by use of an organic alkali metal catalyst at a weight ratio of “synthetic polyisoprene (A): synthetic polyisoprene (B)=10:90 to 90:10”. In the method, preferably, the weight average molecular weight of the synthetic polyisoprene (A) is 100,000 to 3,000,000 and the weight average molecular weight of the synthetic polyisoprene (B) is 1,000,000 to 5,000,000.

First claim

The invention claimed is:

1. A method for producing a synthetic polyisoprene latex, comprising:
a step of mixing a latex of synthetic polyisoprene (A) synthesized by use of a Ziegler catalyst and a latex of synthetic polyisoprene (B) synthesized by use of an organic alkali metal catalyst at a weight ratio of “synthetic polyisoprene (A): synthetic polyisoprene (B)=10:90 to 90:10”.

2. The method for producing a synthetic polyisoprene latex according to claim 1 , wherein
a weight average molecular weight of the synthetic polyisoprene (A) is 100,000 to 3,000,000, and
a weight average molecular weight of the synthetic polyisoprene (B) is 1,000,000 to 5,000,000.

3. The method for producing a synthetic polyisoprene latex according to claim 1 , wherein the latex of synthetic polyisoprene (A) is obtained by once coagulating a polymer solution of synthetic polyisoprene (A) obtained by solution polymerization, in the presence of the Ziegler catalyst, of isoprene dissolved in an organic solvent, to provide a solid material, re-dissolving the solid material in an organic solvent, and emulsifying the resultant obtained by re-dissolving by use of an aqueous surfactant solution.

4. The method for producing a synthetic polyisoprene latex according to claim 1 , wherein the latex of synthetic polyisoprene (B) is obtained by directly emulsifying a polymer solution of synthetic polyisoprene (B) obtained by solution polymerization, in the presence of the organic alkali metal catalyst, of isoprene dissolved in an organic solvent, by use of an aqueous surfactant solution without any coagulation.

5. The method for producing a synthetic polyisoprene latex according to claim 1 , wherein a catalytic system with titanium tetrachloride and an organoaluminum compound is used as the Ziegler catalyst.

6. The method for producing a synthetic polyisoprene latex according to claim 1 , an organomonolithium compound is used as the organic alkali metal catalyst.

7. The method for producing a synthetic polyisoprene latex according to claim 1 , wherein a solid content concentration of the latex of synthetic polyisoprene (A) is 30 to 70% by weight and a solid content concentration of the latex of synthetic polyisoprene (B) is 30 to 70% by weight in mixing of the latex of synthetic polyisoprene (A) and the latex of synthetic polyisoprene (B).

8. A method for producing a latex composition, comprising:
a step of adding a cross-linking agent to a synthetic polyisoprene latex obtained by the method according to claim 1 .

9. A method for producing a dip formed article, comprising:
a step of dip forming a latex composition obtained by the method according to claim 8 .

10. A method for producing a packaging structure that can receive an object to be packaged between a first sheet substrate and a second sheet substrate, comprising:
coating the first sheet substrate and/or the second sheet substrate with a synthetic polyisoprene latex obtained by the method according to claim 1 , to form a coating film, and performing adhesion and stacking of at least a part of the first sheet substrate and at least a part of the second sheet substrate thorough the coating film.

Assignees

• Zeon Corp

Inventors

• Kodemura Junji
• Aihara Shunjin
• Satoh Yoshitaka

Classifications

• C08C19/00

  Chemical modification of rubber · CPC title

• C08L9/10 Primary

  Latex (C08L9/04, C08L9/08 take precedence) · CPC title

• B29C41/14

  Dipping a core {(B29C41/10 takes precedence)} · CPC title

• B29K2105/0064

  Latex, emulsion or dispersion · CPC title

• C08L47/00

  Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, at least one having two or more carbon-to-carbon double bonds; Compositions of derivatives of such polymers (C08L45/00 takes precedence; of conjugated diene rubbers C08L9/00 - C08L21/00) · CPC title