It's been a while since I posted this, yesterday I noticed the ad for free insulation again and stopped by to talk to the shop. I brought a couple of bags home and put a torch to different pieces. They didn't burn at all, but did melt a minute amount.
I have access to the floor/ceiling joists between the first and second floor in my house. The plan is to cut down on the noise from the first floor by filling the cavity with this material. It is about 10" tall.
Before I put some between the floor joists in my house, any objections? Would I dense pack this?
Someone else put it in their ceiling for insulation.
I found this on Wikipedia:
It is hydrophobic, holding less than 1% of its weight in water. It retains much of its insulating powers even when wet. It is machine washable and dries quickly. It is a good alternative to wool (of particular importance to those who are allergic or sensitive to wool). It can also be made out of recycled PET bottles, or even recycled fleece.
Despite its fuzzy appearance and feel, it is not flammable, but instead melts when exposed to flame.
Regular polar fleece is not windproof[6] and
does not absorb moisture (although this is often seen as a benefit, per above).[7][8][9] Fleece readily generates static electricity, which causes the accumulation of lint, dust, and pet hair. It is also susceptible to damage from high temperature washing, tumble drying or ironing. Lower-quality polar fleece material is also prone to pilling.