What Are Metal Processing Aids
Metal processing aids facilitate production and lessen surface flaws in polyethylene films. The active processing aid component will migrate from the polymer to the surfaces of the extruder barrel and die due to its attraction to metal surfaces. The formation of a fine coating at these surfaces lowers the coefficient of friction between the metal and the polymer. The end result is an increase in production rates and a decrease in drug-induced flaws such as melt fracture.
Benefits of Metal Processing Aids
The advantages of using metal processing aids are primarily attained when the polymer is in its molten state, with the principal advancements being:
- Elimination of melt-fracture, a condition brought on by excessive shear stress applied to the molten resin and resulting in roughness in the extruded parts, the appearance of orange peel, shark skin, and other distortions
- Reduces or eliminates turbulence-related capillary flow instability
- Decreases or completely removes die buildup. When released, these residue deposits can lead to flaws on the surfaces of the extruded parts and even snap off the bubble if they are allowed to expand and generate flow lines in the extruded parts.
- Removes surface flaws in pipe extrusion, enhancing the gloss and producing surfaces that are smoother and shiny.
- Shortens the time needed to clean the extruders after a color change.
- Lowers processing temperatures lower pressure during extrusion and increase extruder output