EPDM roofing membrane adhesive system based on hydrogenated styrene-diene-styrene block copolymers

Abstract

This invention is an EPDM roofing membrane adhesive system which comprises an outer protective layer of EPDM and an adhesive layer coated on the underside of said EPDM layer to adhere the membrane to a similarly coated EPDM membrane or to the primed surface of a roof. The adhesive layer comprises from 40 to 60 percent by weight of a hydrogenated styrene-diene-styrene block copolymer having a polystyrene content of from 20 to 40 percent by weight and an overall weight average molecular weight of from 50,000 to 150,000, from 15 to 35 percent by weight of a polyphenylene ether resin having an intrinsic viscosity of less than 0.35 deciliters per gram or of a high softening point endblock resin and from 15 to 35 percent by weight of a tackifying resin. Preferably, the molecular weight of the block copolymer is from 50,000 to 100,000 and the intrinsic viscosity of the polyphenylene ether is less than 0.2.

We claim: 
     
       1. An EPDM roofing membrane adhesive composition which comprises from 40 to 60 percent by weight of a hydrogenated styrene-butadiene-styrene or styrene-isoprene-styrene block copolymer having a polystyrene content of from 20 to 40 percent by weight and an overall weight average molecular weight of from 50,000 to 150,000, from 15 to 35 percent by weight of a polyphenylene ether resin having an intrinsic viscosity of less than 0.35 deciliters per gram, and from 15 to 35 percent by weight of a tackifying resin. 
     
     
       2. The adhesive composition of claim 1 wherein the molecular weight is from 50,000 to 100,000 and the intrinsic viscosity of the polyphenylene ether is less than 0.2. 
     
     
       3. An EPDM roofing membrane adhesive composition which comprises from 40 to 60 percent by weight of a hydrogenated styrene-butadiene-styrene or styrene-isoprene-styrene block copolymer having a polystyrene content of from 20 to 40 percent by weight and an overall weight average molecular weight of from 50,000 to 150,000, from 15 to 35 percent by weight of a end block reinforcing resin, having a ring and ball softening point of 150° C. or more, and from 15 to 35 percent by weight of a tackifying resin. 
     
     
       4. The adhesive composition of claim 3 wherein the molecular weight is from 50,000 to 100,000.