Hi Lulu0915,
Oops … sorry for forgetting to add the link :unsure:
It was post #2 here and I’ve corrected the link in my original reply as well.
Synthetic latex is a copolymer made from a combination of styrene and butadiene and petroleum is the most common but not the only source for both Styrene and Butadiene. There is more about synthetic latex in post #2 here and the posts it links to.
Phoenix