Patent GB-991545-A (GB)
Title: Improvements in or relating to the manufacture of polyetherurethanes
IPC: C08G18/48
Filed: 1961-04-25
Abstract: A method of preparing a polyurethane comprises reacting (1) at least one polyisocyanate with (2) at least one polyol selected from a polyetherpolyol, a mixture of a major amount of a polyether polyol and a minor amount of a polyester polyol, and a polyether-ester polyol having a major amount of ether linkages as compared to ester linkages and containing at least two active hydroxyl radicals in amounts sufficient to form a polyurethane in contact with (3) a minor amount by weight, based on the total weight of polyol present and sufficient to catalyze the reaction between the polyol and the polyisocyanate and to prevent dry heat degradation of the resulting polyurethane, of at least one of the following catalysts, viz. a divalent germanium, tin or lead salt of a carboxylic acid, a divalent germanium, tin or lead derivative of a beta diketone or of an alkyl acetyl acetate or a divalent germanium, tin or lead phenate.  A tertiary amine catalyst, in amount of from 0.05 to 2.5% by weight based on the weight of the polyol may also be present. The reaction may be conducted additionally with a minor amount by weight of a blowing agent sufficient to provide foaming.  In the manufacture of a foamed polyurethane a two-stage process, in which an isocyanate group-containing prepolymer is first prepared, can be used.  As compounds from which the catalysts are derived are listed saturated, unsaturated and aromatic mono- and di-carboxylic acids, salicylic acid, naphthenic acids, acetylacetone, acetoacetic ester, phenol and alkyl-substituted phenols.  A preferred catalyst is a mixture of a tertiary amine, lead naphthenate and stannous octoate.  The polyether polyols may be straight or branched chain and of M.W. 175 to 6500 or more.  A cross-linking agent with 2 to 8 hydroxyl groups may be included in the reaction mixture. Polyesters, if used, may be linear, or branched and may contain amide linkages and amine termination. Glycerides of ricinoleic acid and castor oil can also be present. Impurities and catalysts may be removed from the polyol before the polyurethane formation. The polyisocyanates may be aromatic, aliphatic or aliphatic-aromatic compounds.  As foaming agents water, lithium aluminium hydride, fluoroalkanes, chlorofluoroalkanes can be used.  With water an amine catalyst, e.g. triethylamine, 4-amylpyridine, trihexylamine, N-methylmorpholine, 4-pyridine-propanol, 2-ethanol-pyridine, (di-ethylene amino ethanol) adipate, dibutyl amino ethanol or N,N1-diethyl-2-methyl piperazine is preferably used.  The water may be added as a natural or synthetic rubber and/or resin latex.  To the reaction mixture there may also be added silicones (including siloxane-oxyalkylene block copolymers, silanes, emulsifiers, wetting agents, carbon black, TiO2, SiO2-containing materials, wood flour, metal flakes, organic and inorganic fibres, colour pigments and dyes.  As anti-degradants there may be added alkyl phenols, N,N1-dialkyl phenylene diamines, or alkyl, aryl or halogenated aryl, alkyl, alkaryl, aralkyl and cycloaliphatic phosphites. Foamed products are aged, and, if flexible, may be squeezed or wrung to break the cell walls.  In examples: (1) a prepolymer is prepared by reacting hexanetriol-1,2,6, a propylene oxide adduct of hexanetriol-1,2,6, toluene 2,4- and 2,6-diisocyanates, tri-(2-chlorethyl) phosphite and benzoyl chloride. Foamed product is prepared by mixing prepolymer, propylene oxide adducts of sorbitol and a triol, trichlorofluoromethane and lead naphthenate; (3) stannous octoate catalyst is used in a similar process; (4) flexible foam is obtained from an ethylene oxide-tipped glycerol/propylene oxide adduct, polyalkylene oxide polysiloxane block copolymer, tetramethyl-butanediamine-1,3, toluene diisocyanate, water and stannous octoate; (5) (for comparison) lithium stearate catalyst is used; (6) glycerol/propylene oxide adduct, siloxane block copolymer, water, toluene diisocyanates, cyclic triethylene diamine, lead salicylate and dimethyl-2-amino propanol are reacted; (7) tribasic lead maleate is the catalyst in a similar process; (8) glycerol/propylene oxide adduct, stannous octoate, polyoxyalkylene oxide polysiloxane block copolymer, N-methyl morpholine, toluene diisocyanates, water and triethylene diamine are reacted; (9) in a similar process the catalyst is a mixture of stannous octoate, N - methylmorpholine, tetramethyl-butanediamine-1,3 and lead naphthenate. Reference has been directed by the Comptroller to Specification 901,056.