Classic PU Patent of the Month: ICI on MDI Prepolymers and “Cold Cure” Flexible Foams (1978)

Title: Liquid polyisocyanate compositions

 Number/Link:  EP10850

Applicant/Assignee: Imperial Chemical Industries

Publication date: 14-05-1980

Gist”: Liquid compositions from 2,4’/4,4′-MDI  prepolymers and polymeric MDI.

Why it is interesting: The first polyurethane flexible foams were all based on toluene diisocyanate (TDI).  Other commericially available isocyanates like “pure MDI”  (4,4’/ 2,4′- diphenylmethane diisocyanates mixtures) and “crude MDI” (mixtures of MDI and its higher homologues) were not suited for flexible foam production: the former because of it’s high crystallinity and therefore too high melting point and the latter because of its too high functionality.  This classic invention solved the problem by prepolymerizing  a 2,4’/4,4′-MDI mixture with a “flexible” polyol to an NCO content of 8 to 26% and then adding 10-50% of crude MDI to obtain a liquid composition. These liquid MDI compositions allowed the production of cold cure moulded flexible foams and the first MDI-based car seat cushions.

Cold cure moulded car seat cushions

Cold cure moulded car seat cushions

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1 Comment

  1. Classic PU Patent of the Month: ICI on “High EO – Pure MDI” Flexible Foams (1991) | Innovation in Polyurethanes

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