Use, as modifier resin for rubber mixtures, of novolaks ABC plastified with
terpene-type olefinically unsaturated natural substances C, where the
ratio of the molar amount of the phenol or phenol derivative B and the
molar amount of the natural substance C in the modified novolak is from
1:6 to 6:1, process for increasing the tear propagation resistance and
reducing the compression set of rubber vulcanizates by adding these
modifier resins to rubber mixtures, and components molded from
vulcanizates thus prepared.
