Poor Solvent Resistance of Products Made from Prevulcanised Latex

Manufacturer: We are manufacturers of a wide variety of latex products using prevulcanised NR latex. We have been doing quite well until recently when one of our customers complained that one of our products had poorer resistance to solvent compared to a competitive product which is also made from NR latex. Your comment and advice please.

John Woon (Senior Latex Consultant): Unfortunately your customer's complaint could be justified. Owing to the structure of the rubber of a prevulcanised latex film with weaker particle to particle integration, the film has inferior resistance to oils, greases and non-polar solvents when compared with a film of the same thickness but made from a post-vulcanisable NR latex compound.


Therefore, unlike post-vulcanised film, a prevulcanised film would easily rupture when solvent is dropped onto it while being stretched.

I believe your competitor's product is made from a post-vuclanisable NR latex compound. Your problem could be overcome or minimised if you could introduce some post-vulcanisable latex compound into your prevulcanised latex.

Having said this, you must take note of the fact that natural rubber has comparatively poorer resistance to oils, greases and non-polar solvents compared to Nitrile and polychloroprene rubbers and should not be used in applications where the finished products are to be exposed to such liquids.