| 摘要 |
The invention relates to an elastomeric compound comprising at least one olefinic elastomer comprising ethylene, an α-olefin, from 1 to 7 wt % vinyl norbornene and from 0 to 15 wt % of a second non-conjugated polyene, wherein the wt % are related to the total weight of ethylene, α-olefin, vinyl norbornene and the second non-conjugated polyene, and which elastomer has long chain branching corresponding with &Dgr;δ<20, wherein &Dgr;δ, expressed in degrees, is calculated from the difference between the phase angle δ between stress and strain in a dynamic shear measurement at 125° C. at a frequency of 0.1 rads and the phase angle δ at a frequency of 100 rad/s and the compound further comprising a solid tiller and an oil, such that the compound has a compound loading between 120 and 300 phr, wherein said olefinic elastomer satisfies the following relation Sb>30, wherein Sb is the slope in graph of ln(ac) versus Φ, in which ac is the factor along which the low frequency part (ω<1 rad/s) of the phase angle δ versus ω plots, measured at at least one volume fraction Φ between 0.2 and 1 of the olefinic elastomer in squalane, must be shifted to coincide with a δ versus ω plot of an undiluted polymer (Φ=1), and wherein the δ versus ω plots results from a frequency sweep performed on a stress controlled rheometer carried out at 125° C. under nitrogen atmosphere, using a parallel plate geometry in shear. The invention further relates to a method for the preparation of the compound of the invention.
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