Process for coating a threaded tubular component, threaded tubular component and resulting connection

1. A threaded tubular component, comprising at one of its ends a threaded zone arranged on an outer or inner peripheral surface depending on whether the threaded zone is a male or female end,

wherein at least a portion of the male or the female end is coated with at least one dry film having a Shore D hardness of more than 50 and comprising a mono-component matrix of polyurethane and polyurea; and

a proportion of urethane functionality in the mono-component matrix of polyurethane and polyurea is at least 55% by weight with respect to urea functionality;

wherein the mono-component matrix of polyurethane and polyurea is obtained from a polyol monomer with a molecular mass in the range 300 to 6000 g/mol, a chain extension agent and free aromatic isocyanates which are optionally cured by polyaddition with moisture, and

wherein the mono-component matrix of polyurethane and polyurea comprises:

a multifunctional isocyanate pre-polymer with a functionality of at least 2, prepared from a mixture of a polyether, a polybutadiene or hydroxylated polyester polyols with a molecular mass in the range 300 to 6000 g/mol and aromatic isocyanates of diphenylmethane diisocyanate, in excess;

a co-reagent of a mono- or bis-oxazolidone to initiate reaction and dilute the pre-polymer;

an aliphatic polyisocyanate curing agent of hexamethylene diisocyanate to maintain curing;

a catalyst for the pre-polymer of dimorpholinodiethyl ether or dibutyl tin laurate;

a plasticizer to control foaming during formation of the dry film; and

a moisture scavenger to stabilize the pre-polymer during storage by capturing residual water, said moisture scavenger being p-toluene sulphonyl isocyanate, trimethyl orthoformate or trimethyl orthoacetate.

2. A threaded tubular component, comprising at one of its ends a threaded zone arranged on an outer or inner peripheral surface depending on whether the threaded zone is a male or female end,

wherein at least a portion of the male or the female end is coated with at least one dry film having a Shore D hardness of more than 50 and comprising a mono-component matrix of polyurethane and polyurea; and

a proportion of urethane functionality in the mono-component matrix of polyurethane and polyurea is at least 55% by weight with respect to urea functionality;

wherein the mono-component matrix of polyurethane and polyurea is obtained from a polyol monomer with a molecular mass in the range 300 to 6000 g/mol, a chain extension agent and free aromatic isocyanates which are optionally cured by polyaddition with moisture, and

wherein the mono-component matrix of polyurethane and polyurea comprises:

a multifunctional isocyanate pre-polymer with a functionality of at least 2, prepared from a mixture of a polyether, a polybutadiene or hydroxylated polyester polyols with a molecular mass in the range 300 to 6000 g/mol and aromatic isocyanates of diphenylmethane diisocyanate, in excess;

a co-reagent of a mono- or bis-oxazolidone to initiate reaction and dilute the pre-polymer;

an aliphatic polyisocyanate curing agent of hexamethylene diisocyanate to maintain curing;

a catalyst for the pre-polymer of dimorpholinodiethyl ether or dibutyl tin laurate;

a plasticizer to control foaming during formation of the dry film, and

a CO 2 scavenger of calcium oxide or magnesium oxide to control foaming and formation of bubbles during the reaction.

3. A threaded tubular component, comprising at one of its ends a threaded zone arranged on an outer or inner peripheral surface depending on whether the threaded zone is a male or female end,

wherein at least a portion of the male or the female end is coated with at least one dry film having a Shore D hardness of more than 50 and comprising a polyurethane and polyurea matrix;

a proportion of urethane functionality in the polyurethane and polyurea matrix is at least 55% by weight with respect to urea functionality, and

the polyurethane and polyurea matrix comprises at least one class 1, 2, 3 or 4 solid lubricant as a friction reducing agent, in a proportion by weight in the range 5% to 30%.

4. The threaded tubular component according to claim 3 , wherein the at least one class 1, 2, 3 or 4 solid lubricant is selected from the group consisting of:

a solid lubricant from class 2 of the Bi 2 S 3 type;

a solid lubricant from class 4 of the PTFE type; and

a combination thereof.

5. A threaded tubular component comprising at one of its ends a threaded zone arranged on an outer or inner peripheral surface depending on whether the threaded zone is a male or female end,

wherein at least a portion of the male or the female end is coated with at least one dry film having a Shore D hardness of more than 50 and comprising a polyurethane and polyurea matrix;

a proportion of urethane functionality in the matrix is at least 55% by weight with respect to urea functionality, and

the polyurethane and polyurea matrix comprises a corrosion inhibitor.

6. The threaded tubular component according to claim 1 , wherein the threaded zone is entirely coated with the dry film.

7. The threaded tubular component according to claim 1 , further comprising a metal/metal sealing surface coated with the dry film.

8. A threaded tubular connection, comprising a male threaded tubular component and a female threaded tubular component arranged one into the other,

wherein at least one of said threaded tubular components is the threated tubular component of claim 1 .

9. A method for coating the threaded tubular component of claim 1 for drilling or working hydrocarbon wells, the method comprising:

applying the polyurethane and polyurea matrix in a liquid state to the threaded zone located at one end of the threaded tubular component by spraying over a portion of the end; and

curing the mono-component matrix of polyurethane and polyurea to form the dry film with an essentially rigid structure.

10. The method according to claim 9 , wherein the curing is initiated by applying a relative humidity of at least 60% RH at a temperature of at least 20° C., optionally followed by drying.

11. The method according to claim 10 , wherein the curing comprises drying in an infrared or convection drying oven supplied with water vapour.

12. The method according to claim 9 , wherein the curing occurs with a bi-component spraying device including external mixing of a hardener.

13. The method according to claim 12 , wherein the curing is followed by a stoving or post-curing operation at a temperature of 90° C.

14. The threaded tubular component according to claim 2 , wherein the threaded zone is entirely coated with the dry film.

15. The threaded tubular component according to claim 2 , comprising a metal/metal sealing surface coated with the dry film.

16. A threaded tubular connection, comprising a male threaded tubular component and a female threaded tubular component arranged one into the other,

wherein at least one of said threaded tubular components is the threated tubular component of claim 2 .

17. The threaded tubular component according to claim 3 , wherein the threaded zone is entirely coated with the dry film.

18. The threaded tubular component according to claim 3 , comprising a metal/metal sealing surface coated with the dry film.

19. A threaded tubular connection, comprising a male threaded tubular component and a female threaded tubular component arranged one into the other,

wherein at least one of said threaded tubular components is the threated tubular component of claim 3 .

20. The threaded tubular component according to claim 5 , wherein the threaded zone is entirely coated with the dry film.

21. The threaded tubular component according to claim 5 , comprising a metal/metal sealing surface coated with the dry film.

22. A threaded tubular connection, comprising a male threaded tubular component and a female threaded tubular component arranged one into the other,

wherein at least one of said threaded tubular components is the threated tubular component of claim 5 .