Optical Brightener for PVC pipes https://www.hongyi-chem.com/news/industry-news/pvc-pipes-in-the-spotlight-the-role-of-optical-brighteners.html It is a yellow-green powder, anionic, and its chemical structure is a stilbene derivative. It has a purplish color and is very similar to products like Huntsman's Uvitex NFW. Login Login 0 repins 0 comments 0 likes