| abstract |
A clear hydrophobic TPU is provided by reacting (a) a hydrophobic polyol made from dimerised fatty acid, (b) a chain extender mixture of a linear diol chain extender and a branched diol chain extender, and (c) a diisocyanate. The preferred polyol is a C 36 dimer fatty acid reacted with 1,6-hexane diol. The preferred chain extender mixture is a 75:25 weight ratio blend of 1,12-dodecane diol and 2-butyl-2-ethyl propane diol. The preferred process to make the TPU is a batch process which starts the reaction between about 60°C to 70°C. |