Rubber composite reinforced by at least one steel reinforcing element rendered adhesive by an adhesive composition containing aromatic aldehyde and polyphenol

1. A rubber composite reinforced with at least one steel reinforcing element coated at least in part with an adhesive layer, the reinforced rubber composite comprising a rubber matrix in which the coated steel reinforcing element is embedded, wherein the adhesive layer comprises an adhesive composition comprising at least one phenol/aldehyde resin based on at least:

one aromatic aldehyde bearing at least one aldehyde functional group and comprising at least one aromatic nucleus; and

one polyphenol comprising one or more aromatic nucleus/nuclei,

wherein, if there is only one aromatic nucleus, the one aromatic nucleus bears two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another, the remainder of the aromatic nucleus being unsubstituted, and

wherein, if there is more than one aromatic nuclei, at least two of them each bear two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another and the two positions ortho to at least one of these hydroxyl functional groups are unsubstituted,

wherein the rubber matrix is based on a rubber composition comprising a crosslinking system comprising a content of molecular sulphur ranging from 1 to 5 phr,

wherein the coated steel reinforcing element comprises one or more threadlike reinforcing elements, each comprising a steel core, and

wherein the adhesive layer directly coats a layer of a metal coating directly coating at least a portion of the steel core of the or each threadlike reinforcing element such that no other layer or coating is interposed between the adhesive layer and the metal coating and no other layer or coating is interposed between the metal coating and the steel core.

2. The rubber composite according to claim 1 , wherein the content of molecular sulphur of the crosslinking system of the rubber composition ranges from 1 to 4 phr.

3. The rubber composite according to claim 2 , wherein the content of molecular sulphur of the crosslinking system of the rubber composition ranges from 1 to 3 phr.

4. The rubber composite according to claim 3 , wherein the content of molecular sulphur of the crosslinking system of the rubber composition ranges from 1 to 2.5 phr.

5. The rubber composite according to claim 1 , wherein the content of molecular sulphur of the crosslinking system of the rubber composition ranges from 1.5 to 5 phr.

6. The rubber composite according to claim 5 , wherein the content of molecular sulphur of the crosslinking system of the rubber composition ranges from 2 to 5 phr.

7. The rubber composite according to claim 1 , wherein the rubber composition comprises at least one diene elastomer.

8. The rubber composite according to claim 7 , wherein the at least one diene elastomer is selected from the group consisting of polybutadienes, natural rubber, synthetic polyisoprenes, butadiene/styrene copolymers, isoprene/butadiene copolymers, isoprene/styrene copolymers, butadiene/styrene/isoprene copolymers and mixtures thereof.

9. The rubber composite according to claim 1 , wherein the metal of the layer of the metal coating directly coating at least a portion of the steel core of the or each threadlike reinforcing element is selected from the group consisting of zinc, copper, tin and alloys thereof.

10. The rubber composite according to claim 1 , wherein the aromatic aldehyde bears at least two aldehyde functional groups.

11. The rubber composite according to claim 1 , wherein the at least one aromatic nucleus of the aromatic aldehyde bears two aldehyde functional groups.

12. The rubber composite according to claim 10 , wherein the aromatic aldehyde is selected from the group consisting of 1,2-benzenedicarboxaldehyde, 1,3-benzenedicarboxaldehyde, 1,4-benzenedicarboxaldehyde, 2-hydroxybenzene-1,3,5-tricarbaldehyde and mixtures thereof.

13. The rubber composite according to claim 1 , wherein the aromatic aldehyde is of general formula (A):

in which X comprises N, S or O, and R represents —H or —CHO.

14. The rubber composite according to claim 13 , wherein the aromatic aldehyde is selected from the group consisting of furfuraldehyde, 2,5-furandicarboxaldehyde and mixtures thereof.

15. The rubber composite according to claim 1 , wherein the polyphenol is selected from the group consisting of phloroglucinol, 2,2′,4,4′-tetrahydroxydiphenyl sulphide and mixtures thereof.

16. The rubber composite according to claim 1 , wherein the adhesive composition comprises an unsaturated elastomer latex.

17. The rubber composite according to claim 16 , wherein the unsaturated elastomer of the latex is a diene elastomer.

18. The rubber composite according to claim 17 , wherein the diene elastomer is selected from the group consisting of polybutadienes, butadiene copolymers, polyisoprenes, isoprene copolymers, vinylpyridine/styrene/butadiene terpolymers and mixtures thereof.

19. A process for the manufacture of a rubber composite comprising the steps of:

coating at least a portion of a steel reinforcing element with an adhesive layer; and

embedding the steel reinforcing element in a rubber matrix based on a rubber composition,

wherein the adhesive layer comprises an adhesive composition comprising at least one phenol/aldehyde resin based on at least:

one aromatic aldehyde bearing at least one aldehyde functional group and comprising at least one aromatic nucleus; and

one polyphenol comprising one or more aromatic nucleus/nuclei,

wherein, if there is only one aromatic nucleus, the one aromatic nucleus bears two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another, the remainder of the aromatic nucleus being unsubstituted, and

wherein, if there is more than one aromatic nuclei, at least two of them each bear two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another and the two positions ortho to at least one of these hydroxyl functional groups is unsubstituted,

wherein the rubber composition comprises a crosslinking system comprising a content of molecular sulphur ranging from 1 to 5 phr,

wherein the coated steel reinforcing element comprises one or more threadlike reinforcing elements, each comprising a steel core, and

wherein the adhesive layer directly coats a layer of a metal coating directly coating at least a portion of the steel core of the or each threadlike reinforcing element such that no other layer or coating is interposed between the adhesive layer and the metal coating and no other layer or coating is interposed between the metal coating and the steel core.

20. A tire comprising at least one rubber composite according to claim 1 .

21. A rubber composite reinforced with at least one steel reinforcing element coated at least in part with an adhesive layer, the reinforced rubber composite comprising a rubber matrix in which the coated steel reinforcing element is embedded, wherein the adhesive layer comprises an adhesive composition comprising at least one phenol/aldehyde resin based on at least:

one aromatic aldehyde bearing at least one aldehyde functional group and comprising at least one aromatic nucleus; and

one polyphenol comprising one or more aromatic nucleus/nuclei,

wherein, if there is only one aromatic nucleus, the one aromatic nucleus bears two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another, the remainder of the aromatic nucleus being unsubstituted, and

wherein, if there is more than one aromatic nuclei, at least two of them each bear two or three hydroxyl functional groups in the meta position with respect to each other or with respect to one another and the two positions ortho to at least one of these hydroxyl functional groups are unsubstituted,

wherein the rubber matrix is based on a rubber composition comprising a crosslinking system comprising a content of molecular sulphur ranging from 1 to 5 phr,

wherein the coated steel reinforcing element comprises one or more threadlike reinforcing elements, each comprising a steel core, and

wherein the adhesive layer directly coats at least a portion of the steel core of the or each threadlike reinforcing element such that no other layer or coating is interposed between the adhesive layer and the steel core.