THERMOPLASTIC POLYURETHANES

摘要

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: $\mathrm{rigid}\mathrm{phase}\mathrm{fraction}=\left\{\sum _{x=1}^k\left[\left(m_{\mathrm{KVx}}/M_{\mathrm{KVx}}\right)*M_{\mathrm{Iso}}+m_{\mathrm{KVx}}\right]\right\}/m_{\mathrm{ges}}$ 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.