Patent GB-868996-A (GB)
Title: Improvements in or relating to polyurethane resins
Inventor: DUCK EDWARD WILLIAM
IPC: C08G18/50
Filed: 1958-12-31
Abstract: A process for the preparation of a polyurethane resin comprises reacting under substantially anhydrous conditions an organic isocyanate or isothiocyanate of the general formula R(NCX)n+1, wherein R represents an organic radical, X represents an oxygen or sulphur atom and n is a positive integer, with an organic hydroxy compound which is a condensation product of a trialkanolamine containing in the molecule three hydroxy-alkyl radicals each of which contains at least 3 carbon atoms or a derivative of such a trialkanolamine containing 3 reactive hydroxyl groups in the molecule with an alkylene oxide containing at least 3 carbon atoms in the molecule, in amounts such that the ratio of total -(NCX) groups to total hydroxyl groups in the reaction mixture is greater than 1 : 1. The term "alkylene oxide" is used to denote an organic compound containing an epoxy group capable of reacting with an active hydrogen atom of an ethanolamine to give a condensation product. The polyurethane resin obtained can be converted to a polyurethane plastic by reaction with a compound (e.g. water) containing a plurality of active hydrogen atoms.  A foamed structure results when the evolved carbon dioxide or carbon disulphide forms bubbles in the mixture.  Such polyurethane plastics can also be produced in a single stage by direct reaction between the polyisocyanate, the specified hydroxy compound and a compound containing a plurality of active hydrogen atoms.  The starting materials can be prepared by condensing trialkanolamines containing three hydroxy-alkyl radicals containing at least three carbon atoms with such alkylene oxides as 1, 2-propylene oxide and styrene oxide.  Preferred are compounds in which all the polyoxyalkylene chains attached to the nitrogen have a molecular weight of at least 500.  The condensation products can also be prepared from ammonia or a mono-alkanol-amine or dialkanolamine, the reaction then proceeding via the trialkanolamine.  More than one alkylene oxide, separately or in admixture may be reacted.  Lists of suitable polymethylene, alkylene, alkylidene, cycloalkylene, cycloalkylidene, aromatic and aliphaticaromatic diisocyanates and diisothiocyanates are given.  The polyurethane resin is preferably produced in the absence of alkaline catalysts and non-basic metallic salts.  It can be converted to a synthetic rubber by heating in the presence of catalysts such as alkoxide, inorganic bases and tertiary organic bases.  The resin can also be converted to a plastic by reaction with difunctional compounds such as glycols, diamines, dicarboxylic acids, hydroxy amines, hydroxy acids and amino acids. To form a foamed plastic the resin is reacted with water, hydrogen sulphide, a carboxylic acid or an ester or polyester containing unreacted carboxyl groups.  The polyurethane resin can also be prepared in the presence of an organic solvent such as benzene, toluene, xylene, solvent naphtha, gasoline, carbon tetrachloride ethyl acetate or amyl acetate.  A thin film of the solution may be cured by exposure to atmospheric moisture.  In an example a tri(hydroxypropyl poly(oxypropylene)) amine of average molecular weight 3000 (prepared by reacting 1, 2-propylene oxide and triisopropanolamine) is reacted at 90 DEG C. in the presence of benzoyl chloride with excess toluene-2, 4 and 2, 6 diisocyanates. The syrup produced was stirred with silicone oil and then with water, N-methyl morpholine and triethylamine to give an expanded product.ALSO:A process for the preparation of a polyurethane resin, which can be converted to a polyurethane plastic having a foamed structure, comprises reacting under substantially anhydrous conditions an organic isocyanate or isothiocyanate of the general formula R(NCX) n+1, wherein R represents an organic radical, X represents an oxygen or sulphur atom and n is a positive integer, with an organic hydroxy compound which is a condensation product of a trialkanolamine containing in the molecule three hydroxy-alkyl radicals each of which contains at least 3 carbon atoms or a derivative of such a trialkanolamine containing 3 reactive hydroxyl groups in the molecule with an alkylene oxide containing at least 3 carbon atom in the molecule, in amounts such that the ratio of total -(NCX) groups to total hydroxy groups in the reaction mixture is greater than 1 : 1.  The term "alkylene oxide" is used to denote an organic compound containing an epoxy group capable of reacting with an active hydrogen atom of an ethanolamine to give a condensation product. The polyurethane resin obtained can be converted to a polyurethane plastic by reaction with a compound (e.g. water) containing a plurality of active hydrogen atoms.  A foamed structure results when the evolved carbon dioxide or carbon disulphide forms bubbles in the mixture.  Such polyurethane plastics can also be produced on a single stage by direct reaction between the polyisocyanate, the specified hydroxy compound and a compound containing a plurality of active hydrogen atoms.  The starting materials can be prepared by condensing trialkanolamines containing three hydroxy-alkyl radicals containing at least three carbon atoms with such alkylene oxides as 1,2-propylene oxide and styrene oxide. Preferred are compounds in which all the polyoxyalkylene chains attached to the nitrogen have a molecular weight of at least 500. The condensation products can also be prepared from ammonia or a mono-alkanolamine or dialkanolamine, the reaction then proceeding via the trialkanolamine.  More than one alkylene oxide, separately or in admixture may be reacted.  Lists of suitable polymethylene, alkylene, alkylidene, cycloalkylene, cycloalkylidene, aromatic and aliphatic-aromatic diisocyanates and diisothiocyanates are given. The polyurethane resin is preferably produced in the absence of alkaline catalysts and non-basic metallic salts.  It can be converted to a synthetic rubber by heating in the presence of catalysts such as alkoxides, inorganic bases and tertiary organic bases.  The resin can also be converted to a plastic by reaction with difunctional compounds such as glycols, diamines, dicarboxylic acids, hydroxy amines, hydroxy acids and amino acids. To form a foamed plastic the resin is reacted with water, hydrogen sulphide, a carboxylic acid or an ester or polyester containing unreacted carboxyl groups.  The polyurethane resin can also be prepared in the presence of an organic solvent such as benzene, toluene, xylene, solvent naphtha, gasoline, carbon tetrachloride, ethyl acetate or amyl acetate.  A thin film of the solution may be cured by exposure to atmospheric moisture.  In an example a tri(hydroxypropyl poly(oxypropylene))amine of average molecular weight 3000 (prepared by reacting 1,2 propylene oxide and tri-isopropanolamine) is reacted at 90 DEG C. in the presence of benzoyl chloride with excess toluene 2,4 and 2,6-diisocyanates. The syrup produced was stirred with silicone oil and then with water, N-methyl morpholine and triethylamine to give an expanded product.