Polyurethane Foam Component Lifetimes

摘要

Access deterrent foams are generated by mixing two separately stored and pressurized components upon demand. Investigations have been conducted concerning the aging of both components of three separate polyurethane foam formulations. The polyol component of the first formulation, a propylene oxide adduct of phosphoric acid, hydrolyzes rapidly to give phosphoric acid. Since phosphoric acid can corrode the container as well as adversely affect the final foam properties, a second formulation not containing acid adduct was investigated. This second polyol was isothermally aged at room temperature, 60 exp 0 C and 71 exp 0 C and reactions followed by acid number determination. A reaction between the polyol and the blowing agent, Freon 11, was found to give high acid content. Attempts to add inhibitors to lengthen this initiation period failed. Finally, a third formulation was designed which placed the Freon 11 in the isocyanate component thereby precluding the incompatibility of the blowing agent with the polyol. Subsequent aging studies indicate a long term (6 to 8 years) storage foam system could be achieved. (ERA citation 10:042491)