Bostik Patents High-Styrene SBS Hot Melt Adhesive

February 7, 2013

U.S. 8,163,824 B2
Bostik, Inc. has been granted a patent for a hot melt adhesive comprised of a blend of 5%-40% weight of a styrene-butadiene-styrene block copolymer, the styrene-butadiene-styrene block copolymer is a substantially linear styrene-butadiene-styrene block copolymer having a styrene content of 38%-50% by weight and 0% diblock, and a melt flow index of 3 g/10 min to 11 g/10 min at 190° C with a 5 kg weight, and a polydispersity of 1.01-1.30, and has a weight average molecular weight of 100,000 or higher; 2%-30% weight of an endblock resin wherein the end-block resin has a softening point of from 100˚ to 160° C; 20%-70% of a tackifier; 0%-25% weight of a compatible non-functionalized block copolymer 0%-30% weight of an oil; and 0%-4% weight of an antioxidant; wherein the tackifier is present in an amount greater than the block copolymer and wherein the components total 100% by weight of the composition so that the adhesive has a viscosity less than 10,000 cP at 325° F and a cold flow value equal to or greater than 70% at 49° C after 48 hours.