| abstract |
A rubbery terpolymer is made by copolymerisation of ethylene and an alpha-olefin (e.g. propylene) at a weight ratio of 73:27 to 40:60, and a diolefin (e.g. ethylidene norbornene) in a liquid organic reaction medium with a Ziegler catalyst; the amount of diolefin units is such as to give the terpolymer an iodine value of 10 to 38 and the copolymer has a Mooney viscosity (Ml₁₊₄121 o C) of 135 to 200. n In 100 parts by weight of the polymer is incorporated 30 - 130 parts of a plasticiser, e.g. process oil, and a foaming agent, and preferably vulcanising additives and a filler, and the composition is molded, foamed and crosslinked to make a shaped synthetic rubber sponge useful as a seal for vehicle bodies and which has good compression qualities and hysteresis loss. |