GB971974A - Manufacture of polyurethanes - Google Patents

Abstract

Polyurethanes are produced by the reaction of organic polyisocyanates, hydroxyl group-containing polymers having at least two isocyanate reactive groups per molecule and, at the same time or subsequently a phenol having at least two methylol groups attached to phenolic aromatic rings but not more than two methylol groups on any one phenolic aromatic ring. Suitable phenols specified are dimethylol-p-cresol; dimethylol-o-cresol; 2-chloro-4, 6-dimethylolphenol; 3, 31, 5, 51-tetramethylol-4, 41-dihydroxydiphenylpropane; dimethylol-p-t-butylphenol and dimethylol-p-nonylphenol. The hydroxyl group containing polymers may be linear or branched chain, saturated or unsaturated polyesters or polyesteramides for the production of which many starting materials are specified, or they may be hydroxyl terminated polyethers which are the polymerization or copolymerization products of alkylene oxides which may be initiated by a glycol or a primary monoamine, or they may be branched chain polyethers prepared by polymerizing alkylene oxides in the presence of polyhydric compounds e.g. polyhydric alcohols, alkanolamines, sucrose, phenolformaldehyde reaction products, polyamines, glycidol, 3-hydroxymethylcyclooxabutanes and diepoxides. Many organic polyisocyanates are specified including di-isocyanates, tri-isocyanates, reaction products of an excess of a di-isocyanate with a polyhydric alcohol, uretedione dimers and isocyanurate polymers. The process of the invention is useful in the production of polyurethane coatings and foams. In the production of the latter blowing may be by means of water or a volatile liquid many of which are specified. Water may also be used as a chain extender for the polyurethanes of the invention preferably by using the process of Specification 926,971. Other additives which may be present are surface active agents e.g. oxyethylated phenols, fatty alcohols such as oleyl alcohol, or sulphated methyl oleate, polyalkylsiloxanes and block copolymers thereof with alkylene oxides; flame retardants e.g. b -trichloroethyl phosphate and antimony oxide; plasticizers e.g. tricresyl phosphate and dioctyl phthalate; pigments and fillers e.g. carbon black and silica, antioxidants e.g. t-butylcatechol and sterically hindered phenols; solvents e.g. acetone, cyclohexanone, methyl isobutyl ketone and xylene; flowing out agents such as nitrocellulose, ethyl cellulose, and ureaformaldehyde products; and catalysts e.g. 4-dimethylaminopyridine, iron and manganese acetylacetonates, antimony compounds, dibutyltin dilaurate, stannous octoate, lead acetate, basic lead acetate and lead 2-ethylhexoate. Examples are given of the production of polyurethane lacquers and foams.