Patent Title:  Polyurethane Elastomer with High Ultimate Elongation

 Number/Link: US2018/0312623

Applicant/Assignee:  UNIV PENNSYLVANIA

Publication date: 1 November 2018

“Gist”: Low hardblock polyurethane-polyurea elastomers are prepared from low unsat diols, HDI and a bulky diamine chain extender

Why it is interesting: The current invention relates to PU  elastomers which are said “to  have the highest reported elongation-at-break among known polyurethane elastomers“. The materials are prepared from an NCO-ended prepolymer consisting of a low unsaturated, low dispersity diol and a symmetric diisocyanate (i.e. no 4,4′-MDI), which is reacted with a “bulky” diamine chain extender. In the examples Acclaim 4200 (polyether diol with OHv 28) is used together with HDI and 2-methyl-1,5-pentanediamine. The elastomer showed an elongation at break of more than 2000%.
Because these materials have a low- and non-aromatic hardblock content, it is my opinion that they show creep rather than elasticity.

2-methyl-1,5-pentanediamine