GB1073664A - Polyurethanes - Google Patents

Abstract

A polyurethane is prepared by reacting a polyisocyanate with a polyarylaminopolyether which is obtained by reacting an organic cylic oxide with the reaction product of an arylamine and an aldehyde and which has the general formula <FORM:1073664/C3/1> wherein Ar is the residue of the arylamine, R1 of the aldehyde and R of the organic oxide, n being 1-20 and X being a whole number (see Specification 1,073,663). The preferred polyarylaminopolyethers are prepared from aniline, formaldehyde and propylene oxide, but many other suitable amines, aromatic and aliphatic aldehydes, and aromatic and aliphatic cyclic oxides are listed. The toluene diisocyanates and 3:31-bitolylene-4:41-diisocyanate are the preferred polyisocyanates; others suitable are ethylene, tetramethylene, hexamethylene, cyclohexene-1:2, m- and p-phenylene, 1:5-naphthalene, p,p1-methylene diphenyl, 3:31-dichloro - 4:41 biphenylene, 4 - chloro - 1:3-phenylene, and thiodipropyl diisocyanates and triphenylmethane triisocyanate, and calcium diisocyanate. An excess of 15-35% of isocyanate over hydroxy groups is preferably used, giving a "prepolymer". In the preparation of foams a siloxane surfactant, e.g. a siloxaneoxyalkylene block copolymer, may be used, e.g. in amounts of 0.25-2 wt. per cent of the total. Foaming may be achieved by physical means, e.g. using CHFCl2, CHCl3, CFCl3, CCl4, CH2Cl2, CHFCl, CH3.CH2.CHF2, CH3.CF2.CH3, CCl3.CF2.CH3, C2Cl4Br2, CF2Br2, C2F4Cl2, C2F3Cl3, C2H5Cl, pentane, hexane, heptane, cylohexene, and diethyl ether, amounting, e.g. to 10-60% of the total weight, or by chemical means e.g. using water or a dibasic acid e.g. succinic acid. A basic foaming catalyst is usually employed e.g. 0.5-3 wt. per cent of methyl piperidine, tribenzylamine, pyridine, N:N:N1:N1 - tetramethylbutanediamine, triethylamine, N-methylmorpholine, dimethylethanolamine and N:N1-bis(2-hydroxypropyl)-2-methylpiperazine. Suitable polyols for reaction with the prepolymer include alkoxylated polyols including glycerol, pentaerythritol and a list of sugars and similar alcohols. Conventional dyes, fillers, softeners, plasticizers, wetting agents etc. may be added. In examples propoxylated aniline-formaldehyde products are converted into prepolymers with toluene diisocyanate, and foams are prepared by a two-stage reaction of these with futher polyarylaminopolyethers. In Examples IV and V foams are prepared by reaction of the propoxylated aniline-formaldehyde with a prepolymer from sorbitol and toluene diisocyanate or with a polyisocyanate from phosgene and an aniline-formaldehyde product-the latter a "one-shot" process.