Patent GB-1091483-A (GB)
Title: Improvements in or relating to the production of hydroxy alkoxy alkyl phosphites
Inventor: LOWE ARNOLD JOHN
IPC: C08G18/38
Filed: 1963-10-01
Abstract: Polyether based polyurethane foams are prepared by reacting a polyfunctional organic isocyanate or isothiocyanate of the formula R1(NCX)n+1 where R1 is an organic radical, X is O or S and n is a positive integer with a polyhydroxy polyoxyalkylene glycol ether containing two or more hydroxy groups and water in the presence of a catalyst, e.g. a tin compound or a tertiary amine, together with a foam stabilizer and a phosphite of the general formula <FORM:1091483/C3/1> where (a+b) has an average value of between one and four and b may be zero, and R is non-existent or is a saturated aliphatic diradical having a molecular weight of less than 140 (see Division C2).  All or part of the water may be replaced by a blowing agent. Preferred polyhydroxy polyoxyalkylene glycol ethers are polyoxyalkylene diols of molecular weight 1000 to 3000 and polyoxyalkylene triols of molecular weight 1000 to 6000, also tri- or higher hydroxy polyoxyalkylene glycol ethers with molecular weights between 500 and 1200 and mixtures thereof.  The organic polyisocyanate or isothiocyanate may be aliphatic, aromatic or cyclo-aliphatic and may contain substituent groups. The preferred compounds are those containing 2 to 6 isocyanate or isothiocyanate groups such as polymethylene diisocyanate and diisothiocyanate; hexamethylene diisocyanate; xylene diisocyanate; 1-methyl-2:4-phenylene diisocyanate; 1-methyl 2:6-phenylene diisocyanate; 4,41-diisocyanato-diphenyl methane, tolylene diisocyanate containing about 80% of tolylene-2:4-diisocyanate and 20% tolyene-2:6-diisocyanate and isocyantaes of the formula <FORM:1091483/C3/2> where q is from 0 to 3.  Auxiliary blowing agents specified are halogenated hydrocarbons such as trichlorofluoromethane, dichlorodifluoromethane or methylene dichloride.  The preferred phosphites for use in production of (1) flexible polyether-based polyurethane foams are those with molecular weight in the range 600 to 1200; and for (2) flame-retarded rigid polyurethane foams, those with molecular weights in the range 400 to 650.  The degree of flame-retardancy of the foams may be enhanced by incorporation of conventional flame-retardants such as tris-(2:3-dibromopropyl) phosphatesALSO:The invention comprises phosphites of the general formula <FORM:1091483/C2/1> in which (a + b) has an average value of between one and four, and b may be zero, and R is non-existent or is a saturated aliphatic diradical having a molecular weight of less than 140.  They may be obtained by transesterifying a tri-aryl phosphite, a tri-alkyl phosphite, a di-alkyl aryl phosphite or a di-aryl alkyl phosphite, with a reaction product of 1 : 2-propylene oxide and a saturated aliphatic dihydroxy organic compound, the said reaction product having an average molecular weight of between 100 and 500 and a structure <FORM:1091483/C2/2> Preferred products for reaction with the phosphite esters are those obtained from the reaction of one two moles of 1 : 2-propylene oxide with ethylene glycol or diethylene glycol. Specified transesterification catalysts are CH3OK, NaOH, K2CO3 and C6H5ONa. Also, diphenyl hydrogen phosphite, H3PO3 and diethyl hydrogen phosphite may be used as catalysts.  The products may be used in the production of polyurethane foams (see Division C3).  Examples are given for the production of the phosphites.