Sulfur modified polychloroprene with improved storage stability
AssigneeDenka Chemical Corporation
InventorHubert R. O'Neal
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Abstract
Elemental sulfur modified polychloroprene rubbers having improved Mooney viscosity stability are prepared by blending a sol and a gel in a weight ratio of sol:gel of from 98:2 to 60:40 based on solids, wherein the gel contains 0.5 to 5 weight percent of a cross-linking agent comonomer, a trihydric ester of the general formula ##STR1## wherein x is 0 or an integer of from 1 to 4 and is preferably 0; y is 0 or an integer of from 1 to 4 and preferably 1; R.sub.1, R.sub.2 and R.sub.3 represent hydrogen or an alkyl radical with from 1 to 4 carbon atoms and is preferably CH.sub.3.
Claims13
A polychloroprene sol-gel blend elastomer composition comprising an intimate mixture of:
- a benzene-soluble polymer prepared by polymerizing polymerizable monomer comprising chloroprene in aqueous emulsion containing the chloroprene and 0.1 to 3 parts by weight elemental sulfur chain-transfer agent per 100 parts of monomer and peptizing the product of said polymerization with a peptizing agent containing the nucleus >[(N)(S)].tbd.C--S--, and
- a benzene-insoluble polymer prepared by polymerizing polymerizable monomer comprising at least 50 percent polychloroprene having present in the polymerization system from about 0.5 to 20 weight percent, based on total monomers of a triester having the general formula:
- ##STR8## wherein x is 0 or an integer of from 1 to 4, y is 0 or an integer of from 1 to 4, and R.sub.1, R.sub.2 and R.sub.3 represent hydrogen or an alkyl radical with from 1 to 4 carbon atoms.
A polychloroprene sol-gel blend elastomer composition comprising an intimate mixture of:
- a benzene-soluble polymer prepared by polymerizing polymerizable monomer comprising chloroprene in aqueous emulsion containing chloroprene and 0.1 to 3 parts by weight elemental sulfur chain-transfer agent per 100 parts of monomer and peptizing the product of said polymerization with a peptizing agent and
- a benzene-insoluble polymer.
Dependencies are inferred from the claim text.