I agree with Satine (nice name, btw), poly thread for synthetics like PVC. I know the JoAnns stores here sell the Gutermann brand, you can try there. I've also used the standard Coats & Clark brand without problems, though it's a lesser quality.
I find PVC to be a total pain to work with on a regular home machine (not an industrial machine), but the following tricks have helped me:
- use a leather or denim needle (heavy duty needle)
- use rubber coated paperclips instead of pins (you can get these at any office supply store, the rubber helps grip the fabric without leaving marks)
- get a walking foot for stitching on the back side (keeps each piece from creeping) and get a teflon foot for stitching the top/shiny side (this is essential). You can get each those sewing machine feet at just about any sewing store. about $10-15 each.)
- you can also get some teflon tape from a hardware store and cut a piece for use on a zipper foot (peel it off when you're done)
- a serger/overlock machine works best for stretch materials
- If you don't have a serger/overlock I've used a straight stretch stitch on a regular machine without a problem. I did an entire vinyl jumpsuit this way. (A stretch stitch is like a straight stitch sewn in triplicate. The needle moves forward, then reverses back over the stitch, then forward over the same stitch again -- and it does this for each stitch length. Note, this will add more bulk to the seam because it adds more thread.)
- a short, tight zig zag stitch also works on stretch fabric if you don't have a serger/overlocker. Personally, I prefer to use the straight stretch stitch for things like Lycra or PVC bodysuits and corsets because it's a stronger stitch and I don't have to worry something popping while I'm wearing it. But I'll use the zig zag when I have something that needs a lot of give or isn't a high stress area.
- I use a twin needle (the sewing machine version of a serger/overlock cover stitch) when I have to top stitch on the top/shiny side. This stitch has some stretch and give so it works well, but I wouldn't use it as a load bearing stitch. (You can get a twin needle at any sewing store, package of 2 about $10. YMMV) You can also use a zigzag stitch to topstitch, but I like the look of the twin needle stitching better for most things.
[edit: sorry, I was tired and I meant to say just "twin needle" not twin needle FOOT. it's just 2 needles that are attached together and you use it with a standard foot. I fixed the error there.]
If you google or search here you'll find in depth tips. here is one I had bookmarked. it may help: