Down alternative is probably a fluffy polyester.

pct is a bit of a mystery to me.

I think it probably is NOT Primary Care Trust, as in "Primary Care Trust supports Sexual Health Week 'Pillow Talk' Campaign.

Also probably not Pacific Coast Trail (although Google finds bloggers talking about what pillow they used while on that PCT).

PCT has something to do with patents. Here's a list of patents related to pillows (!)
http://www.professorpatents.com/pillows.htm

Here's another link about patents:
http://www.cbr.gov.pk/newcu/data/Sea...extDesc=covers

Google also found a link to this thread.