A rubber composition having improved tackiness and comprising a natural or synthetic rubber and as a tackifier from 0.3 to 15% by weight (referred to the rubber) of a modified alkylphenol novolak prepared from (A) a phenol component selected from the group consisting of (I) A MONOALKYLPHENOL HAVING FROM 3 TO 18 CARBON ATOMS IN THE ALKYL GROUP, AND (II) A MIXTURE OF (I) WITH UP TO 30 MOL% OF A DIALKYLPHENOL HAVING A TOTAL OF FROM 6 TO 24 CARBON ATOMS IN THE ALKYL GROUPS WITH (B) a substance which is at least trifunctional with respect to formaldehyde and (C) formaldehyde WHEREIN THE MOLAR RATIO OF ONE OF COMPONENTS (I) AND (II): (B) is from 70:30 to 99:1, a method for its preparation and a molded article prepared therefrom.
