Title: STORAGE-STABLE POLYURETHANE-PREPREGS AND FIBRE COMPOSITE COMPONENTS PRODUCED THEREFROM

 Number/Link: WO2013/139704

Applicant/Assignee: Bayer

Publication date: 26-09-2013

“Gist”: Polyurethane matrix materials for prepregs with very good storage stability are prepared from an NCO prepolymer together with isosorbide and delayed action catalysts.

Why it is interesting: Resins for “prepregs” (pre-impregnated fibre composites) need to have a low viscosity upon impregnation, a good storage stability and a fast ‘curing’ reaction preferably at a relatively low temperature.  According to this invention all these properties can be met by using a 8-16% NCO prepolymer made from a polyester polyol and  MDI, together with a dianhydrohexitol (preferably isosorbide) as chain extender and a delayed action catalyst (e.g. a blocked amine) which is activated between 50 and 100°C. The resulting prepregs have a storage stability at room temperature of several weeks. Final Tg is said to be 130°C, which is not very high but should suffice for many applications.

Isosorbide