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

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.

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.