| abstract |
The present invention provides an ethylene type quaternary copolymer rubber which is formed when ethylene, an α-olefin, a non-conjugated diene, and a vinylidene aromatic monomer are polymerized. More specifically, it relates to an ethylene type quaternary copolymer having a low crystallinity which can be easily bonded and blended with a diene type rubber and to which such properties as mechanical strength, abrasion resistance, and resistance to dynamic fatigue can be effectively imparted. The quaternary copolymer rubber in accordance with the present invention has characteristics that (1) the non-conjugated diene has a content of 0.1 to 10 mol%; (2) the vinylidene aromatic monomer has a content of 0.1 to 45 mol%; (3) the limiting viscosity [η] measured at 70°C in xylene is 0.5 to 10 dl/g; (4) the glass transition temperature (Tg) measured by a differential scanning calorimeter (DSC) is a single value and not higher than 0°C; and (5) the portion soluble to methyl ethyl ketone is not greater than 2% by weight. |