Sulfur-crosslinkable rubber-coating mixture

A sulfur-crosslinkable rubberization mixture for metallic strength members, the mixture comprising:

• from 1.2 phr to 1.8 phr of at least one butyl carbamate-functionalized phenol-formaldehyde novolac resin comprising alkyl urethane units and produced by reaction of phenol, formaldehyde and a carbamate resin, wherein the carbamate resin is produced by reaction of butyl urethane with formaldehyde;
• and,
• from 1.2 phr to 1.8 phr of hexamethoxymethylmelamine (HMMM) resin;
• from 0.8 to 1.5 phr of benzothiazyl-2-dicyclohexylsulfenamide (DCBS) as a vulcanization accelerator, and less than 0.5 phr of any other vulcanization accelerators,
• wherein the novolac resin and the HMMM resin are present in a weight ratio of 1:1.5 to 1.5:1, and the novolac resin and the HMMM together are incorporated in an amount of 2.5 phr to 3.5 phr,
• wherein the mixture contains from 0.2 to 2 phr of at least one organic cobalt salt, and
• wherein the mixture is free from resorcinol.