Dual hardness sealing elements for blowout preventer
The present invention relates to sealing elements for blowout preventers comprising a sealing interface region, and a second region, wherein said sealing interface region is formed of a first polymer and said second region is formed of a second polymer, the first and second polymers having different Shore A hardnesses, including sealing elements made of dual hardness polyurethane.
1. A sealing element for a blowout preventer comprising:
a sealing interface region, and
a second region,
wherein said sealing interface region is formed of a first polymer and said second region is formed of a second polymer,
wherein the first polymer has a yield recovery of 75% to 99%;
wherein the first and second polymers comprise polyurethane and the first and second polymers having different Shore A hardnesses as measured by ASTM D2240-15 test method for measuring durometer hardness,
wherein the sealing element comprises an upper portion and a lower portion and wherein either (i) the upper portion of the sealing element is formed from an 60 to <90 shore A polymer and the lower portion of the sealing element is formed from a 90 to 98 shore A polymer or (ii) the upper portion of the sealing element is formed from a 90 to 98 shore A polymer and the lower portion of the sealing element is formed from a 60 to <90 shore A polymer.
2. The sealing element according to claim 1 , wherein
the first polymer has a Shore A hardness of 60 to 95 Shore A and the second polymer has a Shore A hardness higher than the first polymer.
3. The sealing element according to claim 1 , wherein
the sealing element comprises an inner circumferential portion and an outer circumferential portion, wherein the inner circumferential portion of the sealing element is formed from a 60 to <90 shore A polymer and the outer circumferential portion of the sealing element is formed from a 90 to 98 shore A polymer.
4. The sealing element according to claim 1 , wherein
the sealing element comprises an inner circumferential portion and an outer circumferential portion, wherein the inner circumferential portion of the sealing element is formed from an 90 to 98 shore A polymer and the outer circumferential portion of the sealing element is formed from a 60 to <90 shore A polymer.
5. The sealing element of claim 1 , wherein the polyurethane is the reaction product of a polyurethane prepolymer and a curative.
6. The sealing element according to claim 5 , wherein the polyurethane prepolymer is the reaction product of a polyisocyanate and a polyol.
7. The sealing element according to claim 6 , wherein the polyisocyanate is selected from the group consisting of toluene diisocyanate, methylene diphenyl diisocyanate and para-phenylene diisocyanate.
8. The sealing element according to claim 6 , wherein the polyurethane prepolymer comprises less than 1 wt % free polyisocyanate monomer.
9. The sealing element according to claim 6 , wherein the curative is selected from the group consisting of MOCA (4,4′-Methylene-bis(2-chloroaniline)), MDA (4,4′-Methylene dianiline), butanediol (BD) and polycarbonate polyol (A3901).
10. The sealing element according to claim 6 , wherein the polyisocyanate is toluene diisocyanate.
11. The sealing element according to claim 6 , wherein the polyurethane prepolymer comprises less than 0.5 wt % free polyisocyanate monomer.
12. The sealing element according to claim 6 , wherein the polyurethane prepolymer comprises less than 0.1 wt % free polyisocyanate monomer.
13. The sealing element according to claim 1 , further comprising one or more metal inserts.
14. The sealing element according to claim 1 , wherein
the first polymer has a Shore A hardness of 60 to 95 Shore A and the second polymer has a Shore A hardness at least 5 shore A points higher than the first polymer.
15. A spherical or annular blowout preventer including a body, a piston disposed within the body, and a sealing element according to claim 1 disposed adjacent to the piston.