Adhesive for bonding cured EPDM rubber

Abstract

An adhesive for bonding cured EPDM membranes is provided comprising (A) a halogenated butyl rubber (B) a pre-cross linked butyl rubber (C) a styrene/ethylene butylene/styrene block thermoplastic rubber, (D) a thermoplastic petroleum based hydrocarbon feedstock derived aliphatic monomer resin and (E) an aliphatic isocyanate.

What is claimed is: 
     
       1. An adhesive for bonding cured EPDM comprising: (A) a halogenated butyl rubber of the formula: ##STR6## where X is Cl or Br and n is about 50 (B) a pre-crosslinked butyl rubber of the formula: ##STR7## where A is a crosslinking agent and n is about 50 (C) a styrene/ethylene butylene/styrene block thermoplastic rubber,   (D) a thermoplastic, petroleum hydrocarbon feedstock derived aliphatic monomer resin derived from C 5  -C 9  streams polymerized to varying molecular weights to give a softening point range of 162°-181° C. and   (E) an aliphatic isocyanate; wherein (A) is at a concentration of 20.0-45.0 PPHR, (B) is at a concentration of 40.0-65.0 PPHR, (C) is at a concentration of 15.0-20.0 PPHR, (D) is at a concentration of 120-160 PPHR and (E) is at a concentration of 20-35 PPHR.   
     
     
       2. An adhesive of claim 1 where (E) is an aliphatic isocyanate adduct based on 1,6 hexamethylene diisocyanate of the formula: ##STR8## 
     
     
       3. An adhesive of claim 2 wherein said halogenated butyl rubber has a bromine content of 2.0-2.5% or a chlorine content of 1.1-1.3%. 
     
     
       4. An adhesive of claim 2 wherein said pre-crosslinked butyl rubber has a weight percent of solubility in cyclohexane of 15-50 percent. 
     
     
       5. An adhesive of claim 2, wherein said block thermoplastic rubber contains a styrene content of 28-29% by weight, a mid-block content of 71-72% by weight and a tensile strength of 4500-5000 lbs. per square inch. 
     
     
       6. An adhesive of claim 2, wherein said thermoplastic, aliphatic type hydrocarbon resin has a softening point of 175°-181° C., an acid number of less than 1 and a bromine number of 16.0-20.0. 
     
     
       7. An adhesive of claim 2, wherein said aliphatic isocyanate is based on 1,6 hexamethylene diisocyanate adduct with an NCO content of 15.0-17.0 percent concentration. 
     
     
       8. An adhesive composition of claim 2, further comprising an adsorbent of the alkali-metal alumino-silicate zeolite family of compounds at a concentration of 5.0-15.0 PPHR; zinc oxide at a concentration of 0.5-2.0 PPHR; an organic liquid having a solubility parameter of 8.5-8.9, and a hydrogen bonding index of 3.0-3.5 at a total concentration of 500.0-640.0 PPHR resulting in a total solid level of 31.0-37.0 percent and carbon black concentration of 2.0-20.0 PPHR. 
     
     
       9. An adhesive composition of claim 1 wherein A is 1,4 divinyl benzene, methyl divinyl benzene, 1,3 butadiene, isoprene, 2-ethyl 1,3-butadiene, 1,6 hexadiene, 1,6 hexanediol-diacrylate, 2 methyl-1,3-butadiene, butylene glycol dimethacrylate, 1,4 butanediol diacrylate, thiodiglycol dimethacrylate, diallyl maleate, decamethylene glycol diacrylate, 2-chloro 1,3 butadiene, polyethylene glycol dimethacrylate, 1 phenyl ethylene-1,2 dimethacrylate. 
     
     
       10. A process for making an adhesive for the bonding of cured EPDM membrane comprising: (A) Milling or mixing separately .Iadd., with carbon black, about 20.0 to about 45.0 parts PHR of .Iaddend.a halogenated butyl rubber of the formula: ##STR9## where X is Cl or Br and n is about 50 and .Iadd.about 40 to about 65 parts PHR .Iaddend.a pre-crosslinked butyl rubber of the formula: ##STR10## where A=Crosslinking Agent and n is about 50.Iadd., .Iaddend. (B) .[.Solubizing.]. .Iadd.Solubilizing .Iaddend.the butyl rubbers of (A) with .Iadd.about 15 to about 20 parts PHR of .Iaddend.a styrene/ethylene butylene/styrene block thermoplastic rubber, .Iadd.about 120 to about 160 parts PHR of .Iaddend.a thermoplastic, petroleum hydrocarbon feedstock derived aliphatic monomer resin derived from C 5  -C 9  streams polymerized to varying molecular weights to give a softening point range of 162°-181° C., .Iadd.about 20 to about 35 parts PHR of .Iaddend.an aliphatic isocyanate based on an adduct of 1,6.Iadd.-.Iaddend.hexamethylene diisocyanate, .Iadd.about 5 to about 15 parts PHR of .Iaddend.an alkali-metal alumino-silicate zeolite adsorbent, .Iadd.and about 0.5 to about 2 PHR of .Iaddend.zinc oxide .[.and carbon black.]. in an organic liquid having a solubility parameter of 8.5-8.9 and a hydrogen bonding index of 3.0-3.5. .Iadd.   
     
     
       11.  The adhesive of claim 8 or claim 9 which is formulated by the process comprising: (A) milling or mixing separately with carbon black, the halogenated butyl rubber component and the pre-crosslinked butyl rubber component; and   (B) solubilizing the butyl rubbers of (A) with the styrene/ethylene butylene/styrene block thermoplastic rubber component, the thermoplastic petroleum hydrocarbon feedstock, the aliphatic isocyanate, about 5 to about 15 parts PHR of an alkali metal alumino-silicate zeolite adsorbent, and about 0.5 to about 2 parts PHR of zinc oxide in an organic solvent having a solubility parameter of 8.5-8.9 and a hydrogen bonding index of 3.0-3.5, such that the resultant adhesive has a storage stability of greater than 6 months. .Iaddend. .Iadd.12. The adhesive made by the process of claim 10. .Iaddend.