Title: IMPROVED POLYURETHANE FOAM COMPOSITION
Number/Link: WO2013/072380
Applicant/Assignee: SOUDAL
Publication date: 23-05-2013
“Gist”: Use of mono-alcohols to reduce monomeric isocyanate content in OCF systems.
Why it is interesting: OCF , or one component foam (or froth) systems are isocyanate ended prepolymers, mixed with organic blowing agents and other additives like catalysts. They are often prepared directly into pressure cans and are mostly used in construction as adhesives and sealants. Curing happens by reaction with ambient moisture. Recent changes in legislation has forced OCF producers to drop the amount of free monomeric isocyanate in their systems. In this invention OCF systems with less than 1% free monomeric MDI are produced by reacting a conventional diol, a polymeric/monomeric MDI mixture and a relatively low MW monol (2-ethyl-hexanol in the examples). The monol allows to produce prepolymers with low NCO content and low free MDI by preventing chain extension and therefore avoiding extreme viscosity build-up.