Silicone surfactants for the production of open cell polyurethane flexible foams

摘要

A method for preparing a polyurethane flexible foam which comprises reacting an organic polyisocyanate with a polyol in the presence of urethane catalyst, water as a blowing agent, optionally a cell opener, and a polydimethylsiloxane cell stabilizer composition which comprises at least 90 wt % of polydimethylsiloxane molecules having the formula:; $PTEXTPDATMe/PDATHILSBPDAT3/PDAT/SB/HILPDATSi(OSiMe/PDATHILSBPDAT2/PDAT/SB/HILPDAT)/PDATHILSBPDATn/PDAT/SB/HILPDATOSiMe/PDATHILSBPDAT3\; /PDAT/SB/HIL/PTEXT$ ;where n is 5 to 7, provided at least 15 wt % of each of the three molecules in which n is 5, 6 and 7 is present.