Patent GB-1001495-A (GB)
Title: Phosphate ester products suitable for the preparation of fire-resistant polyurethane foams
IPC: C07F9/09
Filed: 1964-01-15
Abstract: Flame retardant polyurethane foams are prepared by reacting polynuclear aromatic isocyanates with polyhydroxy phosphate esters formed by reacting in a first stage a polyphosphoric acid with a polyhydric alcohol having from 2 to 9 hydroxyl groups per mol. and a hydroxyl number of from about 1250 to about 1860 or a condensate thereof with a C2 to C4 alkylene oxide to form an acidic partial ester and in a second stage reacting the said acidic partial ester with sufficient quantity of C2 to C4 alkylene oxide to substantially neutralize the acidity (see Division C2) or by reacting blends of the polyhydroxyphosphate esters with higher polyvalent non-phosphorylated polyhydric compounds having an average functionality of at least 3, such as the polyoxyalkylene ether of a tetritol or hexitol and propylene oxide adducts of diglycerol; 1 : 4-sorbitan, erythritol, methyl glucoside, xylitol, sorbitol, mannitol, glucose or sucrose. The reaction is carried out in the presence of known catalysts for the urethane reaction and foaming agents.  Specified polyols having from 2 to 9 hydroxyl groups are ethylene, diethylene and triethylene glycols; propylene and dipropylene glycols, butylene glycol; glycerol; methyl glycerol, ethylene oxide and propylene oxide adducts of glycerol containing up to 4 oxyethylene or oxypropylene groups per mol.; propylene oxide adducts of sorbitol or of mannitol containing up to 6 oxypropylene groups per mol.; propylene oxide adducts of sucrose containing up to 10 oxypropylene groups per mol., and epichlorohydrin adducts of sorbitol containing up to 4 hydroxychloro-propyl groups per mol.ALSO:A polyhydroxy phosphate ester suitable for use in making polyurethane foams (see Division C3) is obtained by forming an acidic partial ester by the reaction of a polyphosphoric acid with a polyhydric alcohol having from 2 to 9 hydroxyl groups per mol and a hydroxyl number of from about 1250 to 1850 and their adducts with up to twice their own weight of 2- to 4-carbon alkylene oxides, and in a second stage reacting the acidic partial ester with sufficient quantity of an alkylene oxide having from 2 to 4 carbon atoms to substantially neutralize the acidity. Suitable polyols include ethylene, diethylene and triethylene glycols; propylene and dipropylene glycols, butylene glycol; glycerol; methyl glycerol; ethylene oxide adducts of glycerol, propylene oxide adducts of glycerol, of sorbitol, of mannitol, or of sucrose; and epichlorhydrin adducts of sorbitol.  The proportion of polyhydric alcohol to polyphosphoric acid should be at least sufficient to convert all phosphorus present to the orthophosphate form.  The reaction conditions are controlled so that esterification between P-OH and alcoholic hydroxy groups is avoided.  The term polyphosphoric acid is meant to include P2O5 and hydrates thereof containing 1 or 2 P-atoms per mol.  Alkylene oxides which may be used in the second stage of the process include ethylene oxide, propylene oxide, 1,2-butylene oxide and epichlorhydrin. The alkylene oxide is added gradually to the agitated reaction mass from the first stage while controlling the temperature below 100 DEG  C. The reaction is followed by noting the acid number and the addition of alkylene oxide continued until the acid number levels off. Examples are given for the production of phosphate ester mixtures using propylene glycol, glycerol, polyoxypropylene ether of sorbitol, glycerol-propylene oxide adduct containing 3 oxypropylene groups per mol and sorbitol-propylene oxide adduct containing 4 oxypropylene groups per mol, and using propylene oxide and/or ethylene oxide as alkylene oxides in the second stage.