Right @lewm, LP's are made of PVC. But it is my understanding that the terms PVC and vinyl are not synonymous. Am I mistaken? I've seen sheets of vinyl the same thickness as LP's, and the two don't at all look the same. LP's are much stiffer than vinyl.
In any case, LP's (the plural of LP) should not be referred to as vinyls ;-) . IMO, of course.