Abstract: A process for the preparation of thermoplastic polyurethane by reacting (a) isocyanates with (b) compounds reactive toward isocyanates and having a molecular weight (Mw) of from 500 to 10 000 g/mol and (c) chain extenders having a molecular weight of from 50 to 499 g/mol, if appropriate in the presence of (d) catalysts and/or (e) conventional additives, wherein the chain extender mixture consisting of a main chain extender (c1) and one or more co-chain extenders (c2) is used and the thermoplastic polyurethane prepared has a rigid phase fraction of greater than 0.40, the rigid phase fraction being defined by the following formula: rigid ? ? phase ? ? fraction = { ? x = 1 k ? [ ( m KVx / M KVx ) * M Iso + m KVx ] } / m ges with the following meanings: MKVx: molar mass of the chain extender x in g/mol mKVx: mass of the chain extender x in g MIso: molar mass of the isocyanate used in g/mol mges: total mass of all starting materials in g k: number of chain extenders.

Abstract: Thermoplastic polyurethanes which have a hardness of from 50 Shore A to 80 Shore A and are based on (b) polyester diols, wherein a polyester diol (b1) based on butane-1,4-diol and at least one further diol having at least 5 carbon atoms and a polyester diol (b2) based on butane-1,4-diol and at least one further diol having two or three carbon atoms are present as (b) polyester diols.

Abstract: A process for the preparation of thermoplastic polyurethane by reacting (a) isocyanates with (b) compounds reactive toward isocyanates and having a molecular weight (Mw) of from 500 to 10 000 g/mol and (c) chain extenders having a molecular weight of from 50 to 499 g/mol, if appropriate in the presence of (d) catalysts and/or (e) conventional additives, wherein the chain extender mixture consisting of a main chain extender (c1) and one or more co-chain extenders (c2) is used and the thermoplastic polyurethane prepared has a rigid phase fraction of greater than 0.40, the rigid phase fraction being defined by the following formula: rigid ? ? phase ? ? fraction = { ? x = 1 k ? [ ( m KVx / M KVx ) * M Iso + m KVx ] } / m ges with the following meanings: MKVx: molar mass of the chain extender x in g/mol mKVx: mass of the chain extender x in g MIso: molar mass of the isocyanate used in g/mol mges: total mass of all starting materials in g k: number of chain extenders.

Abstract: Thermoplastic polyurethanes which have a hardness of from 50 Shore A to 80 Shore A and are based on (b) polyester diols, wherein a polyester diol (b1) based on butane-1,4-diol and at least one further diol having at least 5 carbon atoms and a polyester diol (b2) based on butane-1,4-diol and at least one further diol having two or three carbon atoms are present as (b) polyester diols.