There are 4 types of purge

Chemical purge
Scrubbing additive (Veromor Purge)
Pre-mixed purge
Volume

Chemical purge

The chemical purge is mixed with polymer – usually polypropylene. The mix is added to the equipment & allowed to stay in the barrel while the chemical action takes place. This can be harmful to equipment & people.

Scrubbing Additive (Veromor Purge)

Additives can be added to polymers that will provide a mechanical scrubbing of the screw & barrel. The additive should also be slightly “sticky”. This allows the carbonized material in the barrel that is being scrubbed to be carried out of the equipment.

Pre-mixed purge

Most pre-mixed purge contain a scrubbing additive that has been blended with polymer carrier. This results in very costly polymer. The effect is very similar to adding a scrubbing additive to polymer

Volume

This method is undertaken by many companies in the belief that it is the lowest cost method. A large quantity of polymer – generally polypropylene – is passed through the equipment. The polymer slowly removes the old polymer and color. The purge polymer generally slides over the old material slowly taking out the old polymer. This is slow & does not remove carbonized material – removal of carbonized material requires a scrubbing action.

Purging the equipment is very necessary when changing color or polymer or when screw & barrel are carbonized. Maximum value can be obtained from equipment when it is operating for maximum hours. If purging is slow, the available production time is reduced.

Many purges are expensive. Machine time is expensive – machine time is "money making" time. A successful purge will be low cost & allow the machine to be back in production quickly. We believe Veromor® Purge provides fast purging at very reasonable cost. Veromor® Purge  -XT, -XS or -XR is used at 20% add rate to the base polymer used to carry it through the machine.