Abstract: A process for preparing a mixture based on a rubberlike copolymer of ethylene, at least one other alpha-alkene and one or more polyenes and tackifying resins which has good building tack.This good building tack can be obtained if the copolymer contains C.dbd.C bonds positioned in the non linear part of the polymer chains, the carbon atoms of which C.dbd.C bonds either have two hydrocarbon groups which are in vicinal cis relative positions and which do not form part of the same cyclic system, or have at least three hydrocarbon groups. In order to obtain the desired high building tack value the mixture must show in unvulcanized state an elongation at break of at least 500% and a tensile strength lying between 1.5 and 50 kg/cm.sup.2. The mixture must be subjected to an artificial light source radiating light with a wave length of between 200 and 300 nm and impacting a radiated energy to the mixture of at least 2 microwatts/cm.sup.2 per nm in the presence of oxygen and a photosensitizer.

Abstract: Rubber mixtures consisting of (1) 20 - 75 parts of a copolymer containing 60 - 80% by weight of ethylene, 20 - 40% by weight of an .alpha.-alkene, and 0 - 20% by weight of one or more polyenes and having, in the unvulcanized state, an elongation at rupture of over 800% and a tensile strength of between 10 and 100 kg/cm.sup.2 ; (2) 80 - 25 parts of at least one polymeric material which is a styrene-butadiene copolymer; polybutadiene or polyisoprene; and (3) a tackifier resin and optionally conventional fillers and additives, wherein the mixture of (1), (2) and (3) has an elongation at rupture of at least 800% and a tensile strength of between 1.3 and 50 kg/cm.sup.2.

Abstract: A process for preparing a mixture based on a rubberlike copolymer of ethylene, at least one other alpha - alkene and one or more polyenes and tackifying resins which has good building tack.This good building tack can be obtained if the copolymer contains C.dbd.C bonds positioned in the non linear part of the polymer chains, the carbon atoms of which C.dbd.C bonds either have two hydrocarbon groups which are in vicinal cis relative positions and which do not form part of the same cyclic system, or have at least three hydrocarbon groups. In order to obtain the desired high building tack value the mixture must show in unvulcanized state an elongation at break of at least 500% and a tensile strength lying between 1.5 and 50 kg/cm.sup.2. The mixture must be subjected to an artificial light source radiating light with a wave length of between 200 and 300 nm and impacting a radiated energy to the mixture of at least 2 microwatts/cm.sup.2 per nm in the presence of oxygen and a photosensitizer.