Water swellable rubber composition suitable for use with oil field equipment
A swellable packer comprising a metallic pipe, and a swellable rubber composition comprising an elastomer, a water soluble resin, for example polyethylene oxide, an ionic peroxide cure and/or peroxide curing with a metallic co-agent, a salt, and a super absorbing polymer wrapped around at least a portion of the metallic pipe.
1. A water swellable rubber composition comprising:
about 100 parts per hundred (PHR) of a nitrile elastomer comprising a Mooney viscosity from about 45 to about 60 at 100° C.;
about 40 PHR of a polyethylene oxide;
about 20 PHR of an ionic peroxide cure and/or peroxide curing with a metallic co-agent comprising an alkylated phenol, a fatty ester, and a zinc diacrylate;
a vulcanizing agent comprising a polymeric sulfur, a rhombic sulfur, and a process oil;
about 126 PHR of a salt; and
about 65 PHR of a super absorbing polymer, clay and/or other natural swelling material,
wherein the nitrile elastomer comprises a bound acrylonitrile content of about 40%.
2. The water swellable rubber composition of claim 1 , wherein the salt is one or more compound selected from the group consisting of metal containing salts comprising metal chlorides, metal phosphates, metal carbonates, metal oxides, metal sulfides, metal hydroxides, metal sulfates, metal acetates, metal bicarbonates, metal formates, metal hydrosulphides, metal imides, metal nitrates, metal nitrides; dissociating salts; and non-metal salts.
3. The water swellable rubber composition of claim 1 , wherein the super absorbing polymer comprises one or more of the following: poly-electrolytes, polyacrylates, polyacryamide-co-polyacrylates, polyacrylamides, acrylic acids, hydrophilic clays, bentonite, wood, cork, and/or cellulose fibers.
4. The water swellable rubber composition of claim 1 further comprising a general purpose plasticizer for rubber products selected from the group consisting of phthalate esters, trimellitates, sebacates, adipates, terephthalates, benzoates, dibenzoates, organophosphates, gluterates, and azelates.
5. The water swellable rubber composition of claim 1 , further comprising carbon black.
6. The water swellable rubber composition of claim 1 , further comprising zinc oxide.
7. The water swellable rubber composition of claim 1 , further comprising a cement or Portland cement.
8. The water swellable rubber composition of claim 1 , further comprising about 35 PHR of a cement of Portland cement.
9. The water swellable rubber composition of claim 1 , further comprising silica.
10. The water swellable rubber composition of claim 1 , further comprising about 30 PHR of silica.
11. The water swellable rubber composition of claim 1 , further comprising about 8-12 PHR of dioctyl phthalate.
12. The water swellable rubber composition of claim 1 , further comprising about 10 PHR of dioctyl phthalate.
13. The water swellable rubber composition of claim 1 , further comprising about 6-10 PHR of carbon black.
14. The water swellable rubber composition of claim 1 , further comprising about 8 PHR of carbon black.
15. The water swellable rubber composition of claim 1 , further comprising about 3-7 PHR of zinc oxide.
16. The water swellable rubber composition of claim 1 , further comprising about 5 PHR of zinc oxide.
17. The water swellable rubber composition of claim 1 , further comprising stearic acid.
18. The water swellable rubber composition of claim 1 , further comprising about 1 PHR of stearic acid.