Degradable polymer composition for use in downhole tools and method of manufacturing

1. A chemical composition for a degradable polymeric material, the chemical composition comprising:

a reaction product of an isocyanate terminated polyester prepolymer, a cross-linking agent, wherein the isocyanate terminated prepolymer as a main chain with a plurality of isocyanates at ends of said main chain, said isocyanate terminated polyester prepolymer having a structural formula below:

ONC—R″—NH—[—CO—R—R′″-]n-NH—R″—CNO, wherein R′″ is selected from a group consisting of —O— and —CO—O—R′—O—,

wherein R is an aryl group,

wherein R′ is an aryl group,

wherein R″ is an aryl group, and

wherein n is a number of prepolymer units corresponding to length of said main chain, wherein said isocyanates are selected from group consisting of 2,4-toluene di-isocyanate, 2,6-toluene di-isocyanate, methylene diphenyl diisocyanate, para-phenyl diisocyanate (pPDI), wherein the cross-linking agent comprises at least one of dimethyl thio-toluene diamine; 4,4′ methylene-bis-(o-chloroaniline), and

wherein the reaction product reaches fracturing failure between 8 hours and 30 days in 0.3% KCl at 90° C., maintain less than 5% weight loss within 2 days and display more than 40% weight loss within 20 days in 0.3% KCl at 90° C., and maintain less than 5% hardness loss within 2 days in 0.3% KCl at 90° C.; and

a dissolution rate accelerating agent, wherein the dissolution rate accelerating agent comprises dibutyltin dilaurate.

2. The chemical composition of claim 1 ,

wherein the reaction product of said isocyanate terminated polyester prepolymer and said cross-linking agent reaches fracturing failure in 0.3% KCl at 90° C. within 15 days, in 1.0% KCl at 93° C. within 4 days, and in 0.3% KCl at 120° C. within 22 hours.

3. The chemical composition of claim 1 ,

wherein the reaction product of said isocyanate terminated polyester prepolymer and said cross-linking agent maintains less than 5% weight loss in 0.3% KCl at 90° C. within 2 days, and wherein said isocyanate terminated polyester prepolymer and said cross-linking agent display more than 40% weight change in 0.3% KCl at 90° C. within 20 days.

4. The chemical composition of claim 1 ,

wherein the reaction product of said isocyanate terminated polyester prepolymer and said cross-linking agent maintains less than 5% weight loss in 0.3% KCl at 90° C. within 2 days, and wherein said isocyanate terminated polyester prepolymer and said cross-linking agent delay more than 60% weight change in 0.3% KCl with said catalyst at 90° C. within 20 days.

5. The chemical composition of claim 4 ,

wherein the reaction product of said isocyanate terminated polyester prepolymer and said cross-linking agent maintain less than 5% hardness loss in 0.3% KCl at 90° C. within 2 days.

6. A chemical composition for a degradable polymeric material, the chemical composition comprising:

a reaction product of an isocyanate terminated polyester prepolymer, a cross-linking agent, wherein the isocyanate terminated prepolymer as a main chain with a plurality of isocyanates at ends of said main chain, said isocyanate terminated polyester prepolymer having a structural formula below:

ONC—R″—NH—[—CO—R—R′″-]n-NH—R″—CNO, wherein R′″ is selected from a group consisting of —O— and —CO—O—R′—O—,

wherein R is an aryl group,

wherein R′ is an aryl group,

wherein R″ is an aryl group, and

wherein n is a number of prepolymer units corresponding to length of said main chain, wherein said isocyanates are selected from group consisting of 2,4-toluene di-isocyanate, 2,6-toluene di-isocyanate, methylene diphenyl diisocyanate, para-phenyl diisocyanate (pPDI), wherein the cross-linking agent comprises at least one of dimethyl thio-toluene diamine, 4,4′ methylene-bis-(o-chloroaniline); and

wherein the reaction product has an average tensile strength over 5000 psi at room temperature with 84 Shore A, an average elongation break over 400% at room temperature with 84 Shore A, an average tensile strength less than 1300 psi with 84 Shore A at 90° C., an average elongation break over 300% at 90° C. with 84 Shore A, and a sealing element made of the material hold a 10000 psi differential over 24 hours; and

a dissolution rate accelerating agent, wherein the dissolution rate accelerating agent comprises dibutyltin dilaurate.

7. The chemical composition of claim 6 ,

wherein the reaction product of said isocyanate terminated polyester prepolymer and said cross-linking agent has an average tensile strength over 4500 psi with 84 Shore A at room temperature, an average tensile strength over 7000 psi with 93 Shore A at room temperature, an average elongation break over 500% with 84 Shore A at room temperature, and an average elongation break over 400% with 93 Shore A at room temperature.

8. The chemical composition of claim 6 ,

wherein the reaction product of said isocyanate terminated polyester prepolymer and said cross-linking agent has an average elongation break over 500% with 84 Shore A at 90° C. and an average elongation break over 300% with 93 Shore A at 90° C.

9. A method for formation of a degradable polymeric material, the method comprising the steps of:

vacuuming a prepolymer unit of claim 1 ;

vacuuming a cross-linking agent;

mixing said prepolymer unit and said cross-linking agent and said dissolution rate accelerating agent so as to form a mixture; and

molding said mixture so as to form a cured polymer as a component.

10. The method for formation, according to claim 9 ,

wherein the step of mixing said prepolymer unit, said cross-linking agent, and said dissolution rate accelerating agent is by centrifuge.

11. The method for formation, according to claim 9 ,

wherein the step of mixing said prepolymer unit, said cross-linking agent said dissolution rate accelerating agent is under vacuum.

12. The method for formation, according to claim 9 ,

wherein the step of mixing said prepolymer unit, said cross-linking agent said dissolution rate accelerating agent further comprises adding a filler.

13. The method for formation, according to claim 12 ,

wherein said filler is selected from a group consisting of carbon blacks, silica, nanographene, nanoclays, nanofibers, and nanotubes.

14. A method for removal, the method comprising the steps of:

forming a chemical composition according to claim 1 into a component;

installing said component in an assembly;

dissolving said component in a solution with salinity less than 0.3% at 90° C. into a degraded component; and

collapsing said assembly so as to remove said assembly and said degraded component.

15. The method for removal, according to claim 14 ,

wherein the step of dissolving said component further comprises a step of: adding a dissolution rate accelerating agent, and

wherein said dissolution rate accelerating agent is selected from a group consisting of: an acid and a base.

16. The method for removal, according to claim 15 , further comprising: dissolving said degraded component completely.