Sulfur-crosslinkable rubber-coating mixture
The present invention relates to a sulfur-crosslinkable rubberization mixture for metallic strength members containing at least one novolac resin comprising alkyl urethane units and produced by reaction of a phenolic compound, an aldehyde and a carbamate resin, wherein the carbamate resin is produced by reaction of alkyl urethane with an aldehyde, and at least one etherified melamine resin. The invention further relates to a pneumatic vehicle tire which comprises at least one such sulfur-crosslinked rubberization mixture. For improved durability of the rubberized strength members, the rubberization mixture contains at least one organic cobalt salt.
1 . 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.
2 . A pneumatic vehicle tire comprising the sulfur-crosslinked rubberization mixture as claimed in claim 1 .
3 . The pneumatic vehicle tire as claimed in claim 2 , wherein the pneumatic vehicle tire comprises a carcass rubberization composed of the sulfur-crosslinkable rubberization mixture.
4 . The pneumatic vehicle tire as claimed in claim 2 , wherein the pneumatic vehicle tire comprises a belt including the sulfur-crosslinkable rubberization mixture and brass-coated steel strength members adhered to the rubberization mixture.
5 . The pneumatic vehicle tire according to claim 4 :
the mixture further comprising:
from 0.4 to 8 phr of sulfur.
6 . The pneumatic vehicle tire according to claim 5 , wherein the novolac resin and the HMMM resin are incorporated into the composition in a weight ratio of 1:1.
7 . The pneumatic vehicle tire according to claim 2 , wherein the rubberization mixture contains only DCBS as the vulcanization accelerator and is devoid of any other vulcanization accelerators.