Permoflex Protein Adhesive is a line of permanently flexible animal glues. Animal glue also known as protein adhesive is typically used in applications such as case making, bench work, and flat mounting. Permoflex Protein Adhesive melts down readily, spreads easily, sets firmly, and will not crack or crystallize. GC-300 Protein Adhesive is widely used in bench work. It offers longer open time with average tack.