A polyolefin which contains the following monomer units: a) not more than 25% by weight of units which are derived from ethene, b) not more than 75% by weight of units which are derived from propene and c) from 5 to 100% by weight of units which are derived from an α-olefin having 4 to 20 carbon atoms, the polyolefin having the following parameters: d) a weight-average molecular weight in the range of from 70 000 to 10 000 000 g/mol, e) a polydispersity in the range of from 4 to 60, f) a melt viscosity, measured by oscillation rheometry at a shear rate of 1 Hz at 190° C., in the range of from 100 000 to 100 000 000 mPa·s, g) a needle penetration in the range of from 3 to 70·0.1 mm, h) an enthalpy of fusion in the range of from 2 to 100 J/g, i) a glass transition temperature Tg in the range of from −15° C. to −80° C. and j) a final melting point of the crystalline fraction in the range of from 85 to 175° C., is compatible both with ethylene polymers and with propylene polymers and is suitable for use in sheets, sealing sheets and shaped articles.