GB1138535A - Improvements in or relating to the manufacture of polyurethanes - Google Patents

Abstract

1,138,535. Polyurethanes; alkoxylated resoles. IMPERIAL CHEMICAL INDUSTRIES Ltd. 25 April, 1966 [11 May, 1965], No. 19831/65. Headings C3C and C3R. Polyurethanes are prepared by reacting an organic polyisocyanate with a polyol which is the reaction product of an alkylene oxide with a resole. The resole is preferably prepared by reacting phenol with formaldehyde in the presence of a basic catalyst but other phenols such as cresols or resorcinol and other aldehydes such as acetaldehyde and glyoxal may be used. Propylene oxide is the preferred alkylene oxide for the reaction with the resole but ethylene oxide, 1,2-butylene oxide or epichlorohydrin may be used. Suitable polyisocyanates are the conventional aliphatic, cycloaliphatic and aromatic diisocyanates, triisocyanates such as toluene-2,4,6-triisocyanate and diphenylether- 2,4,4<SP>1</SP>-triisocyanate, reaction products of an excess of diisocyanate with a trihydric alcohol, uretdione dimers and isocyanurate polymers of diisocyanates. Foamed polyurethanes may be prepared by incorporating water and/or an inert low-boiling liquid in the reaction mixture. Conventional catalysts, surface active agents, foam-stabilizing agents, flame retardants and antioxidants may also be used. The resole may be reacted with the alkylene oxide in the presence of a basic catalyst at 50‹ to 150‹ C. Mixtures of alkylene oxides may be used or the resole may be reacted with two or more alkylene oxides in a multi-stage process, a different alkylene oxide being used at each stage. Examples describe the preparation of a resole from phenol and formaldehyde in the form of formalin which resole is further reacted with propylene oxide. Reference has been directed by the Comptroller to Specification 1,029,033.