Film processing aids slash gel formation. (Keeping up with Additives).

A recent study by researchers at Dyneon LLC, Oakdale, Minn., shows that the company's Dynamar fluoropolymer processing additives (PPM) can significantly reduce gel formation during blown-film extrusion of metallocene polyolefins. Dyneon researchers used a grooved-feed extruder with a decompression screw and a pineapple mixing section. Both screw and mixer have been implicated in gel formation in polyolefin plastomer blown film.

A ten-fold decrease in gel count was observed with Dynamar PPA. Dyneon researchers believe the PPA forms a coating on the metal surface of the extruder that prevents the polymer, oxidized material, and other additives from sticking, accumulating, and eventually sloughing off as gels. Researchers also found that PPA may help clean the extruder by removing previously formed gels from the metal surface. This purging action could initially increase the number of gels in the film. But once purging is complete, Dynamar PPA can reduce gel count in future production.