I understood that polyester thread was more washable. I have a problem with loopy threads wheni use it in my Janome 350E but rayon stitches beautifully. ????

Polyester doesn't fade when you wash garments with some bleach, so I have read. I use Rayon which is much more shiny than polyester.

you got the answer, rayon is a natural fiber, polyester is not, rayon is more shiny than polyester, but polyester is bleach resistance, rayon is not

I like the Robinson Anton rayon thread. Some had problems with thread fading, however, I have never had this problem. H&*

I did a bit of research and put a post on Community. Hope it helps.

Polyester is from oil! Rayon, linen from plant, acetate from wood. Also thread there are 2 standards, so it is impossible to know if wt is the same between manufacturers. Live Laugh Download Stitch!

Rayon is semi-synthetic, it's made of woody fibers by a chemical process; polyester is a synthetic fiber. That in itself does not make a difference in the "filling power", if I may call it that way. I noticed that I can design a lower density when I use polyester than when using rayon, not much, just 4.5 instead of 4.4, but still. I find rayon a bit more pliant and slippery than polyester, maybe that's what causes it. I love the shine of rayon and as I never use detergents that contain bleach (don't even know if you can get those here) I have no problems with fading, not even with towels I embroidered when I got my first embroidery machine in 1993.