Rare-earth catalysed polyisoprene articles
Disclosed herein is a polymeric article having an elastomeric layer including cured synthetic polyisoprene particles that include a rare earth catalysed polyisoprene. The polyisoprene particles may include sulfur crosslinks and/or may be pre-vulcanized. Also disclosed herein are methods for producing polymeric articles having an elastomeric layer including cured synthetic polyisoprene particles that include a rare earth catalysed polyisoprene.
1 . A method for producing a polymeric article, comprising:
pre-vulcanizing an emulsion comprising a rare earth catalysed polyisoprene material comprising a cis-1,4 isomer content of greater than 97.0% by weight; disposing an elastomeric coating of the emulsion comprising the rare earth catalysed polyisoprene material on a former; and
curing the elastomeric coating to form an elastomeric layer of the polymeric article,
wherein the elastomeric layer comprises cured synthetic polyisoprene particles cross-linked by sulfur and a rare earth element content of greater than or equal to 0.1 mg/kg and less than or equal to 100 mg/kg.
2 . A polymeric article produced by a method according to claim 1 .
3 . The polymeric article of claim 2 , wherein the polymeric article is a condom.
4 . The method of claim 1 , wherein the polymeric article comprises a condom and the elastomeric layer forms an open end, a closed end, and a tubular sheath extending from the closed end to the open end.
5 . The method of claim 1 , wherein the cured synthetic polyisoprene particles comprise both intra-polyisoprene particle sulfur-crosslinks and inter-polyisoprene particle sulfur-crosslinks.
6 . The method of claim 1 , wherein a post-vulcanization composition is added to the emulsion before the emulsion is disposed on the former.
7 . A condom comprising:
an elastomeric layer comprising cured synthetic polyisoprene particles that are pre-vulcanized and comprise sulfur crosslinks;
wherein the synthetic polyisoprene particles comprise a rare earth catalysed polyisoprene material that comprises:
a cis-1,4 isomer content of greater than 97.0% by weight; a trans-1,4 isomer content of 1% by weight or less; and
a 3,4 isomer content of 1% by weight or less.
8 . The condom of claim 7 , wherein the elastomeric layer forms an open end, a closed end, and a tubular sheath extending from the closed end to the open end.
9 . The condom of claim 7 , wherein the rare earth catalysed polyisoprene material comprises a branched macrostructure.
10 . The condom of claim 7 , wherein the elastomeric layer comprises a post-vulcanized structure having a molecular weight between crosslinks (Mc) of: less than about: 10500, 10250, 10000, 9750, 9500, 9250, 9000, 8800, 8600, 8400, 8200, 8000, 7800, 7600, 7400, 7200, 7000, 6900, 6800, 6700, 6600, or 6550 g/mol; or less than about 6,540 g/mol.
11 . The condom of claim 7 , wherein the synthetic polyisoprene particles have a maximum median particle diameter of approximately from 1 micrometre.