Low Viscosity Systems for Fibre-Reinforced PU Composites

Title: 2K POLYURETHANE SYSTEMS WITH PHASE SEPARATION – AND-  2K POLYURETHANE SYSTEMS WITH A HIGH GLASS-TRANSITION TEMPERATURE

 Number/Link: WO2013/127732 and WO2013/127734

Applicant/Assignee: Henkel

Publication date: 6-09-2013

Gist”: Low-viscosity, high-potlife 2-component systems useful for the production of composites are prepared from a polyol and isocyanate component characterised only in that polyol and iso are immiscible (case 1) or that the di-iso contains an amount of uretonimine (case 2).

Why it is interesting: These are two rather strange cases.  The claims are very wide and the only ‘inventive step’ for the WO-32 case is that iso and polyol are chosen such that they are incompatible and phase separate after mixing as evidenced by the mixture becoming turbid.  The inventive step in the WO-34 case is that the isocyanate is based on 2,4′ and 4,4′ MDI of which 3-25% (of the NCO) has been converted to uretonimine. Advantages mentioned are low viscosity, long potlife (open time) and a high Tg after crosslinking.  In the examples a polyol/iso mixture is shown with an NCO index of 120, resp 150 without any catalyst or another additives. The ‘surprising effect’ in this invention is not immediatly clear to me and judging from the number of “X”-es in the search report the claims will most likely not get granted as such.

Carbon Fibre Composite

Carbon Fibre Composite

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