GB897203A - Improvements in or relating to the manufacture of polymeric materials - Google Patents

Abstract

A composite article is made by spreading a polyurethane foam-forming mixture on to a substrate, the foam-forming mixture comprising a mixture of a liquid relatively stable prepolymer prepared by reacting a polyester with a polyisocyanate optionally in the presence of a known catalyst for the urethane-forming reaction and without the application of extraneous heat, and a mixture of polyester and water and optionally a catalyst. Preferably the polyester used for forming the prepolymer has a moisture content not exceeding 0,5% by weight. Suitable polyisocyanates are listed and include organic diisocyanates and mixtures thereof with small proportions of triisocyanates. They p may be partially polymerized or modified by treatment with polyhydric alcohols. The polyesters may be made from dicarboxylic acids, or mixtures of acids and glycols or mixtures of glycols and a proportion of a diamine or an amino-alcohol may be added to introduce amide groups. The polyseter used in formation of the prepolymer may differ from that used as the second component. Suitable substrates, which may be flat or curved, include flexible or rigid plastics, or high molecular weight materials, woven or non-woven textiles, wood, metal and paper. The foaming may occur between two substrates, like or unlike, to give laminates, of, e.g. rigid or flexible polyurethane foamed products. An example describes the coating of a rotating paper cylinder. Specification 807,377 is referred to.ALSO:A composite article is made by spreading a polyurethane foam-forming mixture on to a substrate, the foam-forming mixture comprising a mixture of a liquid relatively stable prepolymer prepared by reacting a polyester with a polyisocyanate optionally in the presence of a known catalyst for the urethane-forming reaction and without the application of extraneous heat, and a mixture of polyester and water and optionally a catalyst. Preferably the polyester used for forming the prepolymer has a moisture content not exceeding 0,5% by weight. Suitable polyisocyanates are listed and include organic diisocyanates and mixtures thereof with small proportions of triisocyanates. They may be partially polymerized or modified by treatment with polyhydric alcohols. The polyesters may be made from dicarboxylic acids or mixtures of acids and glycols or mixtures of glycols and a proportion of a diamine or an amino-alcohol may be added to introduce amide groups. The polyester used in the formation of the prepolymer may differ from that used as the second component. Specification 807,377 is referred to.ALSO:A composite article is made by spreading a polyurethane foam-forming mixture on to a substrate, the foam-forming mixture comprising a mixture of a liquid relatively stable prepolymer prepared by reacting a polyester with a polyisocyanate optionally in the presence of a known catalyst for the urethane foam-forming reaction and without the application of extraneous heat, and a mixture of polyester and water and optionally a catalyst. Preferably the polyester used for forming the prepolymer has a moisture content not exceeding 0,5% by weight. Suitable polyisocyanates are listed and include organic diisocyanates and mixtures thereof with small proportions of triisocyanates. They may be partially polymerized or modified by treatment with polyhydric alcohols. The polyesters may be made from dicarboxylic acids or mixtures of acids and glycols or mixtures of glycols and a proportion of a diamine or an amino-alcohol may be added to introduce amide groups. The polyester used in the formation of the prepolymer may differ from that used as the second component. Specification 807,377 is referred to.