Styrene/butadiene copolymer is a chemical compound, a styrene by-product.

Significant substances used in the production method:
Benzene, ethenyl-, 1,3-butadiene.

Safety
Styrene is a fat-soluble organic molecule obtained from the Friedel-Crafts reaction between benzene and ethylene. It is a residual monomer that can be absorbed through the skin. It can cause neurotoxic effects.
Kraeling, M. E., & Bronaugh, R. L. (2005). In vitro percutaneous absorption of acrylamide and styrene from cosmetic vehicles through fuzzy rat and human skin. Cutaneous and Ocular Toxicology, 24(1), 65-79.

What it is used for and where
Cosmetics

Opacifying agent. It is useful into formulations that may be translucent or transparent to make them opaque and less permeable to light.
Synonyms:

CAS: 9003-55-8