GB891776A - Improvements in or relating to the manufacture of polymeric materials - Google Patents

Abstract

The preparation of polyethers from compounds containing more than two hydroxyl groups with compounds containing at least one 1,2-epoxy group in the presence of a catalyst is characterized by reacting the epoxide with a solution of the polyhydroxylic compound in water to the stage where the reaction product of polyhydroxylic compound and epoxide is liquid at temperatures above 90 DEG C. and the reaction products of epoxide and water are still removable by distillation, removing these latter products together with excess water by distillation, and further reacting the reaction product of polyhydroxylic compound and epoxide with more epoxide. The epoxide in the final stage may be different from the first. Specified polyhydroxylic compounds are glycerol, trimethylolpropane, sorbitol, trimethylolethane, pentaerythritol, tetramethylolcyclohexanol, sucrose, a -methylglucoside, mannitol, inositol, quebrachitol, polyvinyl alcohol, and molasses. The preferred epoxide is propylene oxide; others include ethylene and butylene oxides, epichlorhydrin and glycidol, and poly epoxides such as 1,2-3,4-diepoxybutane, dialkyl ether dioxide and 2,6-dioxaspiro(3,3)-heptane, preferably in admixture with a major proportion of a monoepoxide. Alkaline catalysts are preferred. The products may be converted to rigid or flexible, cellular or homogenous polyurethanes by reaction with polyisocyanates. Examples are given. In (3), an oxypropylated sucrose resin is mixed with minor amounts of water and a polysiloxane/polyoxyalkylene block copolymer and with a diphenylmethane diisocyanate composition, and formed into a rigid polyurethane foam in a mould.ALSO:The preparation of polyethers from compounds containing more than two hydroxyl groups with compounds containing at least one 1,2-epoxy group in the presence of a catalyst is characterized by reacting the epoxide with a solution of the polyhydroxylic compound in water to the stage where the reaction product of polyhydroxylic compound and epoxide is liquid at temperatures above 90 DEG C. and the reaction products of epoxide and water are still removable by distillation, removing these latter products together with excess water by distillation, and further reacting the reaction product of polyhydroxylic compound and epoxide with more epoxide. The epoxide in the final stage may be different from the first. Specified polyhydroxylic compounds are glycerol, sorbitol, trimethylolpropane, trimethylolethane, pentaerythritol, tetramethylolcyclohexanol, sucrose, a -methylglucoside, mannitol, inositol, quebrachitol, polyvinyl alcohol and molasses. The preferred epoxide is propylene oxide; others include ethylene and butylene oxides, epichlorhydrin and glycidol, and polyepoxides such as 1,2-3,4-diepoxybutane, diallyl ether dioxide and 2,6-dioxaspiro(3,3)-heptane, preferably in admixture with a major proportion of a monoepoxide. Alkaline catalysts are preferred. Examples are given. A diphenylmethane diisocyanate composition, used for converting the products to polyurethanes (Example 3), is prepared by phosgenating a crude diaminodiphenylmethane containing about 15% polyamines (mainly triamines) obtained by condensing formaldehyde with aniline in the presence of hydrochloric acid.ALSO:Polyethers, prepared from polyhydroxylic compounds and 1,2-epoxides and which are free from polyalkylene glycols (see Group IV(a)), are reacted with polyisocyanates to form rigid or flexible polyurethane foams. In Example 3, an oxypropylated sucrose resin is mixed with minor amounts of water and a polysiloxane/polyoxyalkylene block copolymer and with a diphenylmethane diisocyanate composition, and formed into a rigid polyurethane foam in a mould.