Wool Production

[Brian Rose]

You'll see Pakistani kilts that say "wool" while some say "acrylic wool" (whatever that's supposed to be).

I was always puzzled by the "100% virgin acrylic" labels often seen on sweaters ( jumpers).

[MichiganKyle]

I was always puzzled by the "100% virgin acrylic" labels often seen on sweaters ( jumpers).

This actually makes a huge difference for some applications. Virgin plastic means it's fresh from the polymerization process and hasn't been blended with recycled plastic. It's generally a better grade of plastic. I'm no material scientist, but from what I understand, recycled or semi-recycled plastic tends to have shorter polymer chains as well as impurities from recycled products' additives (colorants, flame retardants, etc.) as well as contamination (labels made from different plastics, glues, improperly sorted plastics, etc.) and a variety of different variants in a similar family being mixed together under the same recycling code (PET, PETT, PETG, etc.). Most 3D printer plastic is made from virgin feedstock for consistency of melting temperature, flow, and physical properties. Variation in anything (even tiny diameter variations in the few hundredths of a millimeter range) can mess up 3D prints, so virgin feedstock tends to be pretty much a hard requirement for it. I assume other fields have the same issues with recycled plastics where a particular material quality or at the very least process consistency is needed. Recycled plastics are great for some applications, but not everything.

[MichiganKyle]

I should note, too, that it is possible, in certain cases, to 3D print with recycled plastics. Some people have homemade extruders to be able to recycle their failed prints back into usable filament. But it's only really useful where you control everything about the feedstock, like if you know the ground-up plastic feedstock is all from failed prints that are exclusively PLA of a particular melt temperature, for example. Even then, I've heard of people having problems with it due to the shorter polymer chains from the regrinding process. Recommendations seem to be to freeze your prints before grinding them, IIRC. The reports I've seen make it sound like you'd really only want to use it for decorative applications, and nothing load-bearing like a mounting bracket, due to the inconsistencies and degradation in the recycled plastic.

Proper plastic recycling is not at all a trivial process.