Color Switching

[Louis]

Precolored pellets, concentrate or powder?

[Skip]

Whether powder, pellets, or concentrates, I've always used a run sequence from lightest color ( or clear) to darkest colors---the transition from light to dark is MUCH LESS than the other way. In addition, a twin screw extruder (positive displacement gear pump type behavior) will exhibit a much lower transition than a single screw extruder.

[Louis]

True Skip, light to dark for sure!

But I asked as precolored will purge quicker than concentrate added to virgin, which will purge quicker than powder added to virgin. The latter may need a little moisture to facilitate quick changes.

[alexkm]

I am manufacturer of gasket of refrigerator recently the color of surface of this product change from white to pink.
Does anyone knows what is the reason of that?

[Len]

My guess,
Pink staining, very common.
Mold or other micro-organisms are attacking (eating) the plasticized PVC.
Len