Rubber Accelerators

Influence of Accelerators on the Structure, Properties and Processing of Synthetic Polyisoprene Latex

Abstract
Synthetic polyisoprene polymer is made up of the same monomer unit 'isoprene' as in natural rubber. This material has been developed to provide the benefits of natural rubber and eliminate the potential for Type 1 protein allergic reactions. However the synthetic polymer during its polymerisation process shows some inconsistencies in terms of stereo-regularity and molecular weight characteristics. Irregularities in polymer structure can sometimes account for dipping and vulcanisation variability. It results in processability difficulties giving inferior and inconsistent balance of properties compared to natural rubber films.

The paper describes how utilising novel safer accelerators (developed by Robinson Brothers Limited) and modification of the film forming technology can overcome variability in the processing of polyisoprene latex, improving the desired physical properties and making them more consistent. It will also show how the mechanism of action of safer accelerators DIXP (Robac AS100) and ZDNC (Arbestab Z ), developed to reduce Type IV allergy and nitrosamine issues, differ from conventional ultra accelerators to provide a practical solution and ease any processing difficulties of the latex.

Khirud B Chakraborty, Roger Couchman, Ranvir S Virdi, Craige Taylor
Robinson Brothers Ltd., West Bromwich, B70 0AH, England