Crystals on vulcanized NBR articles

[asankaglove]

We are making rubber gloves using NBR rubber grades.Currently we are having serous problem because very tiny and shine crystal particles are coming onto glove surface with the time. With our preliminary testing we have clues that this is not sulfur blooming.
We suspect that few possible reasons.

Particles are shiny, white in color and very small.

Please send if you have idea or a method to clarify the material.

Thanks

 

[GrahamBennett]

It's very difficult to give you a definitive answer without knowing what the formulation you are using is as you have already ruled out sulfur, which is the usual suspect. Are you using any wax by any chance?

 

[asankaglove]

we suspect that accelerator ,and stearate complex with Zinc iron.. is it possible.. zinc can be present in former releasing agent as zinc stearate. We are using thiocarbamate as a accelerator. we suspect there is no sufficient time to complete sulfur cross links with this accelerator. So there may be residual accelerator which has been combined with sulfur. We tested the crystal for sulfur. But there were not any sufficient clue for elemental sulfur. But we suspect that sulfur can be present in the complex. same time it is in crystal phase

 

[stancom]

Chemical analysis is really the only way to identify the deposit. One always suspects a dithiocarbamate bloom and sometimes you can detect this by rubbing your finger with a copper containing coin or object and then pressing it against the surface. A brown discoloration should develop after the change to a cupric dithiocarbamate. I'm not convinced about undercure unless your vulcanizate properties fall short of optimum.