GB1476830A - Process for the preparation of polyurethanes - Google Patents

Abstract

1476830 Polyurethanes RHONE POULENC INDUSTRIES 27 June 1975 [28 June 1974] 27351/75 Heading C3R A process for the preparation of a foamed or unfoamed polyurethane comprises reacting an organic polyol and an organic polyisocyanate in the presence of a catalyst comprising bis -N- (6 - dimethylaminohexyl) methylamine, generally in an amount of from 1 x 10<SP>-3</SP> to 3000 x 10<SP>-3</SP> mol per mol of polyol, and optionally a metallic or organo-metallic catalyst, the ratio of the number of metal atoms of the said metallic catalyst to the number of tertiary nitrogen atoms of the said amine catalyst generally being from 0À1 to 1. Suitable metallic catalysts are dibutyl tin dilaurate, stannic chloride, stannous octate, stannous oleate, dibutyltin bis-(2-ethyl hexoate), ferric chloride, cobalt benzoate and cobalt 2-ethylhexoate. The polyisocyanate can be any conventional aromatic, aliphatic or cycloaliphatic diisocyanate or a prepolymer. Suitable polyols are polyhydric polyethers, polyesters, polyesteramides, polyurethanes or hydrocarbons, or optionally modified caster oil, or a silanol or siloxane etherified with a polyhydric polyether or polyester. The reaction mixture may also comprise trimerization catalysts e.g. alkali metal salts of phenols or an alkali metal hydroxide; catalysts for the formation of carbodiimide groups e.g. phospholines and phospholine oxides; regulators of the urethane-forming reaction e.g. malonitrile, acetylacetone and benzoylacetone; conventional foaming agents and surfactants and other additives. In the Examples foams are prepared from reaction mixtures comprising bis-N- (6 - dimethylaminohexyl) methylamine in dipropylene glycol, a siloxane/alkylene oxide block copolymer surfactant, either a polyisocyanate obtained by the phosgenation of an aniline-formaldehyde condensate consisting mainly of 4,4<SP>1</SP>-diisoocyanato-diphenylmethane, or tolylene diisoocyanate and either (1) water, fluorotrichloromethane and a polyol mixture consisting of an adduct of propylene and ethylene oxides to a mixture of sucrose and propylene glycol, and an ethylene oxide/triethanol-amine adduct; or (2) fluorotrichloromethane and a propylene oxide/ glycol glucoside adduct; or (3) water, stannous octoate and an adduct of ethylene and propylene oxides to glycerol.