Patent Title: THERMOPLASTIC POLYURETHANE
Number/Link: WO2015/173337
Applicant/Assignee: Henkel
Publication date: 19-11-2015
“Gist”: TPU is made using diols with 1 prim- and one sec-OH group
Why it is interesting: Thermoplastic polyurethanes (TPU) have many desirable properties but are notoriously difficult to process: they need a high processing temperature (>160°C ) and have a high melt viscosity requiring high shear processing equipment. According to the current invention the melt viscosity can be greatly reduced by using an asymmetric diol as chain extender (i.e. with one pimary and one secondary hydroxyl group) instead of a conventional symmetric diol. In the examples polyester-MDI TPUs extended with asymmetric diols (e.g. 1,3-butanediol or 2,2,4-trimethyl-1,3-pentanediol) are shown to have a much lower melt viscosity compared to TPU extended with 1,4-butanediol. These TPUs are especially useful as hotmelt adhesives.
2,2,4,-trimethyl-1,3-pentanediol
