Would any body know about or wore any vintage courtelle/polyester cardigans such as from littlewoods, marks &s?

WHAT DOES IT MEAN BY COURTELLE OR POLYESTER IN A CARDIGAN AS I HAVE ALWAYS LIKED THE SO CALLED VINTAGE CARDIGANS THAT YOU COULD ONCE BUY FROM LITTLEWOODS AND MARKS & SPENCERS ETC THAT DIDN'T FEEL LIKE WOOL WHAT SO EVER BUT JUST A NYLON SHEEN FEEL TO THEM, BUT ALAS THEY DON'T MAKE CARDIGANS LIKE THIS ANY MORE.