PVB is a resin.Our Mowital grades are named using a self explaining nomenclature. The trade-name Mowital is followed by a capital B stating the aldehyde used. In this case the products are based on butyraldehyde. The numbers refer to the degree of poly-merization, the higher the number the higher the degree of polymerization (vis-cosity). The suffixes T, M, H, S and HH indicate the degree of acetalization, T being the lowest and HH being the highest.