We have been producing secondary granules (Stretch, LDPE) for 2 years. Since this year, we have started producing Stretch film (flat-slot extruder) from our granules. We want to achieve good quality, the HELICS interfere. the photo shows there are small and large ones. The goal is to get rid of the big ones. I understand it is not possible to get rid of it at all. Large ones are very noticeable to the eye and to the touch.
The Chinese granulator is now 2 years old. Productivity is not decreasing yet (if we talk about screw wear). Diameter 100mm, length 3m. (30:1) — 5 heating zones, plus the head (water ring cutting). Processing temperatures — auger (140-170) head and filters 180. Built-in compactor, the loading of raw materials is adjustable. There are 2 degassing zones — on the 3rd and 4th heating zones. One, on the 4th zone, had to be silenced — it often climbed into degassing. Now — only if the grid is clogged. We use mesh weaving — ordinary (square) with 0.3 and 0.4 mm cells (we put two). The raw materials are dry, not mine, but we sort them well. The color of the granule depends on the dustiness of the raw material, from light (almost white) to dark gray. Only the color of the produced film changes from the color of the pellet, the Helics have the same number and size.
Temperatures on a flat-gel extruder 160-190 on augers, 200 — mixing device (two augers), on the head — 210 edges 225. at the outlet, the melt 230-235gr. — measured by a pyrometer.
1) are the large inclusions in the photo HELICS or maybe other polymers?
2) what could be the reason?;
3) if these are Helics, what chemistry can be eliminated and at what stage: at the granulation stage or during the production of the film. (there must be some kind of heat stabilizers or antioxidants)