| abstract |
Processing aids comprising (a) 10-50% by weight of hydrophobized, at least partially aggregated, metal oxide particles chosen from the group consisting of aluminium oxide, silicon dioxide and mixtures of the abovementioned metal oxides, (b) 20-75% by weight of one or more thermoplastic polyurethanes, (c) 0, 5-25% by weight of one or more isocyanates, (d) 0, 5-15% by weight of one or more compounds which act as lubricant and dispersant, the sum of the constituents (a) to (d) amounting to at least 90% by weight, based on the processing aid. Use of the processing aid in the processing of thermoplastic polyurethanes to give films, hoses, cable sheathings, injection mouldings or fibres. Process for the preparation of a self-supporting film, characterized in that a mixture of a thermoplastic polyurethane and from 0, 5 to 35 by weight, based on the thermoplastic polyurethane, of the processing aid is metered into an extruder and the mixture is melted and extruded via a film blowing die to give a film. |