Adhesive composition and method for providing water-tight joints in single-ply roofing membranes

Abstract

A cured adhesive tape composition for adhering together roofing materials such as synthetic EPDM rubber and which provides long term water tightness is provided. The adhesive composition includes substantially equal amounts by weight of a) a rubbery polymer comprising a blend of an ethylene-propylenediene terpolymer, a halogenated butyl rubber or a halogenated copolymer of p-methylstyrene and isobutylene, and polyisobutylene b) a compatible tackifier, and c) an accelerator/cure package for the rubbery polymer. The cured composition exhibits a peel strength of at least 715 grams/cm at room temperature, at least 300 grams/cm at 70° C., and supports a static load of at least 300 grams at 70° C.

What is claimed is:  
     
       1. A cured adhesive composition for adhering together EPDM roofing materials comprising substantially equal amounts by weight of a) a rubbery polymer comprising a blend of an ethylene-propylene-diene terpolymer, a halogenated butyl rubberor a halogenated copolymer of p-methylstyrene and isobutylene , and polyisobutylene and b) a compatible tackifier, said composition further comprising an accelerator/cure package for said rubbery polymer, said composition being fully vulcanized prior to use by heating to achieve essentially full crosslinking of the components, said composition having a peel strength of at least 715 grams/cm at room temperature, at least 300 grams/cm at 70° C., and supports a static load of at least 300 grams at 70° C. 
     
     
       2. The composition of  claim 1  further including a minor portion of carbon black. 
     
     
       3. The composition of  claim 1  in which said tackifier is selected from the group consisting of polybutene, a phenolic resin, and mixtures thereof. 
     
     
       4. A cured adhesive composition for adhering together roofing materials consisting essentially of: a) from about 35-45% of a rubbery polymer, b) from about 35-45% of a compatible tackifier, c) from about 5-9% of a plasticizer, and d) from about 1-6% of an accelerator/cure package, the resulting composition being fully vulcanized prior to use by heating to achieve essentially full crosslinking of the components, said composition being cured sufficiently to support a static load of at least 300 grams at 70° C., have a peel strength of at least 715 grams/cm at room temperature and at least 300 grams/cm at 70° C. 
     
     
       5. The composition of  claim 4  in which said rubbery polymer comprises a blend of an ethylene-propylenediene terpolymer, a halogenated butyl rubber, and polyisobutylene. 
     
     
       6. The composition of  claim 4  in which said rubbery polymer comprises a blend of an ethylene-propylenediene terpolymer, a halogenated copolymer of p-methylstyrene and isobutylene, and polyisobutylene. 
     
     
       7. The composition of  claim 4  in which said tackifier is selected from the group consisting of polybutene, a phenolic resin, and mixtures thereof. 
     
     
       8. The composition of  claim 4  in which said plasticizer is liquid polyisobutylene. 
     
     
       9. A roofing membrane adhesive tape comprising a layer of a cured adhesive composition in the form of a strip on a release liner, said adhesive composition comprising substantially equal amounts by weight of a) a rubbery polymer comprising a blend of an ethylene propylene-diene terpolymer, a halogenated butyl rubberor a halogenated copolymer of p-methylstyrene and isobutylene , and polyisobutylene and b) a compatible tackifier, said composition further comprising an accelerator/cure package for said rubbery polymer, said composition having been postcured after formulation but before use by heating to achieve essentially full crosslinking of the components and having a peel strength of at least 715 grams/cm at room temperature, at least 300 grams/cm at 70° C., and supports a static load of at least 300 grams at 70° C. 
     
     
       10. The composition of  claim 9  further including a minor portion of carbon black. 
     
     
       11. The composition of  claim 10  in which said tackifier is selected from the group consisting of polybutene, a phenolic resin, and mixtures thereof. 
     
     
       12. A roofing membrane adhesive tape comprising a layer of a cured adhesive composition in the form of a strip on a release liner, said adhesive composition comprising substantially equal amounts by weight of a) a rubbery polymer comprising a blend of an ethylenepropylene-diene terpolymer, a halogenated copolymer of p-methylstyrene and isobutylene, and polyisobutylene and b) a compatible tackifier, said composition further comprising an accelerator/cure package for said rubbery polymer, said composition having been postcured after formulation but before use and having a peel strength of at least 715 grams/cm at room temperature, at least 300 grams/cm at 70° C., and supports a static load of at least 300 grams at 70° C. 
     
     
       13. A cured adhesive composition for adhering together EPDM roofing materials comprising substantially equal amounts by weight of a)  a rubbery polymer comprising a blend of an ethylene - propylene - diene terpolymer, a halogenated copolymer of p - methylstyrene and isobutylene, and polyisobutylene and b )  a compatible tackifier, said composition further comprising an accelerator/cure package for said rubbery polymer, said composition being fully vulcanized prior to use by heating to achieve essentially full crosslinking of the components, said composition having a peel strength of at least  715  grams/cm at room temperature, at least  300  grams/cm at  70 ° C., and supports a static load of at least  300  grams at  70 ° C.   
     
     
       14. The composition of  claim 13 , further including a minor portion of carbon black. 
     
     
       15. The composition of  claim 13  in which said tackifier is selected from the group consisting of polybutene, a phenolic resin, and mixtures thereof. 
     
     
       16. The roofing membrane adhesive tape of  claim 12  wherein said composition is postcured after formulation but before use by heating to achieve essentially full crosslinking of the components. 
     
     
       17. The roofing membrane adhesive tape of  claim 16  further including a minor portion of carbon black. 
     
     
       18. The roofing membrane adhesive tape of  claim 17  in which said tackifier is selected from the group consisting of polybutene, a phenolic resin, and mixtures thereof.