Polystyrene-polyisoprene-polystyrene block copolymers, hot melt adhesive compositions, and articles produced therefrom

Claim 1

A hot melt adhesive composition useful in bonding a polyethylene or polypropylene substrate to a tissue, or non-woven article at temperatures below that damaging to the substrate while providing superior heat resistance superior static time to failure with low viscosity, good peel adhesion and tack in the assembly of disposable articles which comprises from about 15 percent to about 35 percent based on the weight of the hot-melt adhesive composition, of an A-B-A block copolymer wherein the B component is polyisoprene having an average molecular weight ranging from about 30,000 to about 70,000, the A component is polystyrene having an average molecular weight ranging from about 12,000 to about 20,000, the overall molecular weight of the block copolymer ranges from about 60,000 to about 110,000 and wherein the A component is present in an amount of at least 27 parts to about 50 parts per 100 parts by weight of the block copolymer, from about 45 percent to about 70 percent of a compatible primary tackifying resin, based on the weight of the hot-melt adhesive composition, from 0 percent to about 30 percent of a plastizing oil or secondary tackifying resin, based on the weight of the hot melt adhesive composition, and from about 0.1 percent to about 2 percent of a stabilizer, based on the weight of the hot-melt adhesive composition.