Butene-1 (Co)Polymers having low isotacticity

摘要

Butene-1 (co)polymers characterized by the following properties: content of butene-1 units in the form of isotactic pentads (mmmm) from 25 to 55%; intrinsic viscosity [&eegr;] measured in tetraline at 135° C. from 1 to 3 dL/g; content of xylene insoluble fraction at 0° C. from 3 to 60%; and a ratio ES2/ES1≧1, where ES1 is the boiling diethyl ether soluble fraction determined on the polymer as such and ES2 is the boiling diethyl ether soluble fraction determined after milling the polymer. The butene-1 (co)polymers show a good balance between processability and elastomeric behavior.