Appearance of Whitish Powder on Rubber Products

Manufacturer: We are facing problem with the appearance of whitish powder on our finished products after storage. Our detailed latex compound formulations and samples of the good and defective products have been sent to you for your study. Please guide us on how we could overcome this problem.

John Woon (Senior Latex Consultant): Thanks for your samples and the compound recipe. After some initial tests and observation, I've concluded that this problem was very likely to be due to "blooming" of some of your additives, particularly the dithiocarbamate accelerators i.e. migration of some compounding chemicals to the surface of the rubber, as a result of low solubility in the rubber concerned.

All ingredients used in rubber compounding should have maximum solubility possible in the rubber.
Usually the higher the molecular weight of the accelerator, the more soluble it is in the rubber and hence lesser tendency to bloom.

My detailed report on how to prevent or minimize blooming has been sent to you separately. Hope you would find this useful.