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1. Concepts in Removal of Carbon Contamination
Molten resin carbonizes if it remains inside a molding
machine for long periods of time or comes into contact
with air, resulting in formation of a thin layer on the
surfaces of the molding machine’s cylinder and screw.
This partially cross-linked / carbonized resin film gradually
enlarges over time, and at some point pieces of the film
start to peel off. These pieces are the carbon contaminants
that can become mixed in with the molded parts, and represent
one cause of product defects. Since these films adhere
so strongly to metal surfaces, they cannot be removed even
with resins such as polyethylene or polystyrene. CELPURGE
combines a component that plasticizes, penetrates, and
swells the partially cross-linked / carbonized film, making
it peel away easily from metal surfaces. Furthermore, this
carbide film–removing component is not a surfactant.
This is a big difference between surfactant type purging
compounds and CELPURGE.
2. Concept of filled grades
MA2 is the basic grade of CELPURGE
and has superior removal capability of carbon contamination.
However, certain partially cross-linked / carbonized layers
that have accumulated over long periods of time adhere very
stubbornly and cannot be easily eliminated even with MA2.
In these cases, filled grades are very effective.
The fillers
in filled grades serve to strike a blow that can breach the
carbide film. Once the film is damaged, the plasticizing
component (that differs from a simple surfactant) can easily
penetrate. Finally, CELPURGE's core cleaning
power cleans up the partially cross-linked / carbonized layers.
3. Combination of filled grades and MA2
To the extent that
fillers are added to increase abrasion, there is a corresponding
decrease in the amount of CELPURGE's original active
component. This means that its ability to remove the remaining
carbide film after it has been damaged by filled grades slightly
compromised. In this case, you can compensate by using MA2
at the same time. This is especially the case with AG4.
This
can be compared to cleaning stuck-on food from a frying pan.
The most effective way is to first go after the stuck-on
food with a metallic scouring brush. Once the food begins
to loosen up, you can probably get a better overall “clean” by
finishing off with a sponge. Filled grades and MA2 work in
a similar manner as the scouring brush and sponge.
( Please
also refer to “Characteristics
of AG4 and AW2.” )
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