How to Minimize Copper Staining While Maintening Dithiocarbamates in the Compound Fromulations

Manufacturer: We are a medium sized factory manufacturing latex thread and other dipped products. In one of our products we would like to minimize copper staining. We also want good heat resistance. However we do not want to replace dithiocarbamate in your latex compound. What shall we do?

John Woon (Senior Latex Consultant): It is not easy to prevent copper staining without removing dithiocarbamates from your latex compound formulations. However, I have the following suggestion to control the staining:

1) Try reducing the level of dithiocarmate to the very minimal while adding a thiazole (ZMBT) as the main accelerator. The reduced level of dithiocarbamate is such that it still gives you reasonable rate of vulcanization and physical properties of the final products.

2) If you are using ZDEC, replace it with ZDBC as the latter has lesser tendency to cause migration staining.

As for heat resistance, you can try sulphur donors such as TMTD, DPTT or Morpholine disulphide in conjunction with thiazoles.