Metal surface treatment

1. A method of treating a first metallic surface (S1) intended to be bonded to a second surface (S2) by adhesive bonding, and for imparting a resistance to the adhesive failure to the bonding, comprising treating a metallic surface (S1) with at least one polymer P obtained by radical copolymerization of a mixture of (i) acrylic acid; (ii) methacrylic acid; and (iii) at least one 2-hydroxyethyl methacrylate phosphate of Formula (a) below:

wherein n is 1 or 2;

wherein the mixture has the following molar ratio, based on the total quantity of acrylic acid, methacrylic acid and 2-hydroxyethyl methacrylate phosphates of formula (a):

acrylic acid: from 65 to 90%,

methacrylic acid: 5 to 30%,

2-hydroxyethyl methacrylate phosphates: 2 to 12%; and

wherein the second surface (S2) is a metallic surface.

2. The method of claim 1 , wherein the at least one polymer P imparts to the bonding a resistance to corrosive atmospheres and to wet atmospheres.

3. The method of claim 1 , wherein the polymer P has a molecular weight of at least 7,500 Da.

4. The method of claim 1 , wherein the metal surface (S1) is a surface comprising a metal selected from aluminum, steel, zinc, magnesium titanium, copper and their alloys, or cobalt-nickel alloys.

5. The method according to claim 3 , wherein the metal surface (S1) is a surface of aluminum or aluminum alloy.

6. The method of claim 1 , wherein the polymer P is used for treating both surfaces (S1) and (S2) before the adhesive bonding of the two surfaces.

7. The method of claim 1 , wherein the polymer P is obtained by radical copolymerization of a mixture having the following molar ratio, based on the total quantity of acrylic acid, methacrylic acid and 2-hydroxyethyl methacrylate phosphates of formula (a):

acrylic acid: from 80 to 90%

methacrylic acid: 5 to 15%

2-hydroxyethyl methacrylate phosphates: 2 to 10%.

8. The method of claim 1 , wherein the polymer P has a molecular weight of at least 10 kDa to 1500 kDa.

9. A process for bonding a first metallic surface (S1) with a second metallic surface (S2) including:

treating said first surface (S1) with at least one composition including at least one polymer P obtained by radical copolymerization of a mixture of (i) acrylic acid; (ii) methacrylic acid; and (iii) at least one 2-hydroxyethyl methacrylate phosphate of Formula (a) below:

wherein n is 1 or 2;

wherein the mixture has the following molar ratio, based on the total quantity of acrylic acid, methacrylic acid and 2-hydroxyethyl methacrylate phosphates of formula (a):

acrylic acid: from 65 to 90%,

methacrylic acid: 5 to 30%,

2-hydroxyethyl methacrylate phosphates: 2 to 12%; and

optionally treating the second metallic surface (S2) with at least one composition including the at least one polymer P; and

bonding the surfaces (S1) and (S2) via an adhesive composition applied between the two surfaces.

10. The process according to claim 9 , wherein the composition comprising the polymer P is:

a conversion composition including the polymer P; and/or

a solution or a dispersion of the polymer P; and/or

the adhesive composition, that comprises the polymer P.

11. The process according to claim 10 , wherein the solution or dispersion of the polymer P is applied on the surface after having applied a conversion coating on the surface to be treated.

12. The process according to claim 9 , wherein the metallic surface (S1) is a surface comprising a metal selected from aluminum, steel, zinc, magnesium titanium, copper and their alloys, or cobalt-nickel alloys.

13. The process according to claim 9 , wherein the metal surface (S1) is a surface of aluminum or aluminum alloy.

14. The process according to claim 9 , wherein the polymer P is used for treating both surfaces (S1) and (S2) before the adhesive bonding of the two surfaces.

15. A material comprising two adhesive-bonded surfaces including a first metal surface comprising a metal surface (S1) which is in all or part (i) treated with a polymer P and (ii) bonded to a second metallic surface (S2), via an adhesive, said material being a material having a metal surface (S1) in all or part covered by:

at least one coating comprising the at least one polymer P; and/or

a layer comprising a reaction product of the polymer P with a metal of the treated surface or another compound present in said layer, or the polymer P strongly linked with said other compound,

wherein polymer P is obtained by radical copolymerization of a mixture of (i) acrylic acid; (ii) methacrylic acid; and (iii) at least one 2-hydroxyethyl methacrylate phosphate of Formula (a) below:

wherein n is 1 or 2;

wherein the mixture has the following molar ratio, based on the total quantity of acrylic acid, methacrylic acid and 2-hydroxyethyl methacrylate phosphates of formula (a):

acrylic acid: from 65 to 90%,

methacrylic acid: 5 to 30%,

2-hydroxyethyl methacrylate phosphates: 2 to 12%.