Methods for crosslinking polymer compositions in the presence of atmospheric oxygen

Patent metadata

Field	Value
Publication number	US-9644089-B2
Application number	US-201414772796-A
Country	US
Kind code	B2
Filing date	Feb 28, 2014
Priority date	Mar 14, 2013
Publication date	May 9, 2017
Grant date	May 9, 2017

Abstract

A process for crosslinking an elastomer composition in the presence of an organic peroxide formulation is disclosed. The organic peroxide formulation may comprise additional compounds chosen from bis-, tri- and higher poly-maleimides, bis-, tri- and higher poly-citraconimides, peroxide-crosslinkable silicone elastomers, p-phenylenediamine based antiozonants, sulfur containing organic compounds which are accelerators for the sulfur curing (crosslinking) of polymers which are curable/crosslinkable by sulfur, and polysulfide polymers. Methods of manufacturing elastomer articles, methods of reducing mold-fouling, elastomer compositions, and elastomer articles made from the elastomer compositions are also disclosed.

First claim

We claim:

1. A process for curing an elastomer composition in the presence of oxygen, the process comprising the steps of:
A) mixing at least one elastomer comprising ethylene-propylene terpolymer, at least one non-elastic co-polymer comprising at least two different monomers in polymerized form, wherein the elastomer and non-elastic co-polymer are present in the elastomer composition at weight ratios from 50:50 to 75:25, and at least one organic peroxide formulation to provide a mixture, wherein the elastomer is saturated or unsaturated, the polymer is saturated or unsaturated, and said polymer does not comprise chlorinated polyethylene or chlorosulfonated polyethylene; and wherein the organic peroxide formulation comprises i) at least one organic peroxide, ii) at least one moiety chosen from bis-, tri- and higher poly-maleimides, and bis-, tri- and higher poly-citraconimides, and iii) at least one sulfur accelerator;
B) curing said mixture in the presence of oxygen.

2. The process of claim 1 , wherein the elastomer consists of saturated ethylene-propylene terpolymer.

3. The process of claim 1 , wherein the non-elastic co-polymer is unsaturated poly(ethylene propylene).

4. The process of claim 1 , wherein the at least one organic peroxide is selected from the group consisting of dialkyl peroxides, diperoxyketals, mono-peroxy carbonates, cyclic ketone peroxides, diacyl peroxides, organosulfonyl peroxides, peroxyesters and peroxydicarbonates.

5. A cured elastomer composition prepared by the process of claim 1 .

6. An elastomer composition curable in the presence of oxygen, said composition comprising:
A) at least one elastomer comprising ethylene-prorlene terpolymler which is saturated or unsaturated;
B) at least one non-elastic co-polymer comprising at least two different monomers in polymerized form and which is saturated or unsaturated;
C) at least one organic peroxide;
D) at least one compound chosen from bis-, tri- and higher poly-maleimides, and bis-, tri- and higher poly-citraconimides; and
E) at least one sulfur accelerator;
wherein said at least one polymer does not comprise chlorinated polyethylene or chlorosulfonated polyethylene;
wherein elastomer and non-elastic co-polymer are present in the elastomer composition at weight ratios from 50:50 to 75:25;
such that said elastomer composition crosslinks in the presence of oxygen.

7. The composition of claim 6 , wherein the at least one organic peroxide is selected from dialkyl peroxides, diperoxyketals, mono-peroxy carbonates, cyclic ketone peroxides, diacyl peroxides, organosulfonyl peroxides, peroxyesters and peroxydicarbonates.

8. The composition of claim 6 , wherein the elastomer consists of saturated ethylene-propylene terpolymer and the at least one non-elastic co-polymer is unsaturated poly(ethylene propylene).

9. A method for manufacturing an article comprising an elastomer composition curable in the presence of oxygen, said elastomer composition comprising:
A) at least one elastomer comprising ethylene-propylene terpolymer;
B) at least one non-elastic co-polymer comprising unsaturated poly(ethylene propylene);
C) at least one organic peroxide;
D) at least one compound chosen from bis-, tri- and higher poly-maleimides, bis-, tri- and higher poly-citraconimides, and p-phenylenediamine based antiozonants; and
E) at least one sulfur accelerator;
wherein said at least one polymer does not comprise chlorinated polyethylene or chlorosulfonated polyethylene;
wherein the elastomer and non-elastic co-polymer are present in the elastomer composition at weight ratios from 50:50 to 75:25;
such that said elastomer composition crosslinks in the presence of oxygen;

said method comprising the steps of:
extruding said elastomer composition in the presence of hot air to form an uncured preform article;
curing said uncured preform article.

10. The method of claim 9 , wherein curing said extruded preform comprises curing using microwaves or a steam autoclave.

11. The method of claim 9 , wherein extruding and curing the elastomer composition are performed continuously.

12. The method of claim 9 , wherein extruding and curing the elastomer composition are performed continuously in a hot air tunnel.

13. The method of claim 9 , wherein said article is a seal, hose, or gaskets.

14. A method for manufacturing an article comprising an elastomer composition curable in the presence of oxygen, said elastomer composition comprising:
A) at least one elastomer comprising ethylene-propylene terpolymer which is saturated or unsaturated:
B) at least one non-elastic co-polymer comprising at least two different monomers in polymerized form and which is saturated or unsaturated;
C) at least one organic peroxide;
D) at least one compound chosen from bis-, tri- and higher poly-maleimides, and bis-, tri- and higher poly-citraconimides; and
E) at least one sulfur accelerator;
wherein said at least one polymer does not comprise chlorinated polyethylene or chlorosulfonated polyethylene;
wherein the elastomer and non-elastic co-polymer are present in the elastomer composition at weight ratios from 50:50 to 75:25;
such that said elastomer composition crosslinks in the presence of oxygen,

said method comprising the steps of:
injecting molding, compression molding or transfer molding the elastomer composition.

15. A process for reducing mold-fouling in the presence of oxygen during the manufacture of elastomer articles, comprising:
A) supplying an uncured elastomer composition to a mold, wherein the uncured elastomer composition comprises saturated ethylene-propylene terpolymer, at least one non-elastic unsaturated co-polymer which is poly(ethylene propylene), wherein the elastomer and non-elastic co-polymer are present in the elastomer at weight ratios from 50:50 to 75:25 at least one organic peroxide formulation, wherein said at least one organic peroxide formulation comprises i) at least one organic peroxide, ii) at least one moiety chosen from bis-, tri- and higher poly-maleimides, bis-, tri- and higher poly-citraconimides, and p-phenylenediamine based antiozonants, and iii) at least one sulfur accelerator;
B) curing the elastomer composition to form an elastomer article; and
C) releasing the cured elastomer article from the mold.

16. The process of claim 15 , wherein the at least one organic peroxide is selected from the group consisting of dialkyl peroxides, diperoxyketals, mono-peroxy carbonates, cyclic ketone peroxides, diacyl peroxides, organosulfonyl peroxides, peroxyesters and peroxydicarbonates.

17. The process of claim 1 , wherein the elastomer consists of saturated ethylene-propylene terpolymer, the non-elastic co-polymer is unsaturated poly(ethylene propylene), and the moiety is chosen from bis-, tri- and higher poly-maleimides, and bis-, tri- and higher poly-citraconimides.

Assignees

• Arkema Inc

Inventors

• Ranbom Wayne
• Palys Leonard H

Classifications

• C08L23/30 Primary

  by oxidation · CPC title

• B29C47/0004

  Operations & Transport · mapped topic

• B29K2105/0005

  containing compounding ingredients (releasing, lubricating or separating agents B29C33/56, fibers B29K2105/08, B29K2105/12; fillers B29K2105/16, recycled material B29K2105/26) · CPC title

• B29K2105/24

  crosslinked or vulcanised · CPC title

• C08J2423/16

  Ethene-propene or ethene-propene-diene copolymers · CPC title