First, my monthly reminder: There are no toxic plastics, none of them. Our materials are safe and do far more good for the environment than harm. When you meet anyone who thinks otherwise, try to find out why they want to believe the contrary so fiercely. You may be surprised and maybe even sympathetic. If you ask for statistics, toxicity data and their sources, you probably won’t get any, or they will be selective or come from questionable sources. Anything you think is really significant, please let me know.
Now, I can talk about extrusion. I’ve done a good deal of extrusion troubleshooting over the years, and found that many people want to believe that the equipment is the problem. If we can just change the screw or the screen pack or maybe do something to improve cooling, the problem(s) will go away. That sometimes happens, of course, but I’m a chemical engineer and my “grad school” was my job in tech service for a resin supplier, so I also look to materials for solutions, especially because that’s where most of the money goes, too.
One thing we can do is blend resins with each other. We often do this, anyway, if we work our trim and scrap into the product, but sometimes it makes sense to blend two or more different resins. For example, we might blend some regular LDPE with LLDPE to raise the speed we can run without melt fracture. Proportions will depend on needed properties and relative resin costs.