Patent GB-731071-A (GB)
Title: Preparation of elastomers from polyalkylene ether glycols and diisocyanates
IPC: C08G18/30
Filed: 1952-07-01
Abstract: A polymer is made by heating together a polyalkylene glycol having a molecular weight of from 750-10,000 with a molar excess of an arylene diisocyanate.  Elastomers are made by (a) performing at least the latter part of the reaction in presence of water, or (b) reacting the polymer with water.  Preferably, 2-12 mols. of diisocyanate are used per mol. of glycol and 0.5-1.5 mols. of water are used per mol. of diisocyanate.  Closed cell sponges result if the polymer is reacted with an amount of water at least equal to its mass (preferably 1-6 times its mass) and if desired in presence of a solvent, e.g. acetone or dioxane.  Preferably the reaction between the glycol and diisocyanate and the reaction between the polymer and water is performed in presence of an acid-reacting substance, e.g. an inorganic or organic acid chloride, bromide or iodide or an inorganic acid and also the salt of a tertiary nitrogen or tertiary phosphorus base.  Specified glycols are polyethylene, polypropylene, polybutylene, poly - 1,2 - dimethylethylene and polydecamethylene glycols and polydioxolane.  Specified diisocyanates are tolylene - 2,4-, metaphenylene-, 1-chloro-phenylene-2,4-, and naphthalene-1,5-, diisocyanates and their dimers and methylene bis-(4-phenyl isocyanate).  In examples: (1) polyethylene glycol is stirred with tolylene-2,4-diisocyanate at 70 DEG  C., water is added and the mass worked into a sheet on a rubber mill and pressed; (2) polyethylene glycol is heated with meta-phenylene diisocyanate or the dimer of tolylene-2,4-diisocyanate to 70 DEG  C., water is added and the mass further milled, dried and pressed; (3) polyethylene glycol, tolylene-2,4-diisocyanate, benzene and pyridine (which forms a salt with acid in the glycol) are heated to 60 DEG  C. and the product formed into a film; (4) the polymers from polyethylene glycol and tolylene-2,4-diisocyanate or meta-phenylene diisocyanate are reacted with water to produce an elastomer soluble in dimethyl formamide; (5) and (6) the polymers from polypropylene glycol and tolylene-2,4-diisocyanate or methylene bis-(4-phenyl isocyanate) are reacted with water; (7) the polymer obtained by reacting polyethylene glycol with tolylene-2,4-diisocyanate in presence of benzoyl chloride is reacted with water in presence of a pyridine salt; (8) polyethylene glycol is heated with tolylene-2,4-diisocyanate first alone and then in presence of a pyridine salt; the resultant polymer is reacted with water; (9) the polymer obtained by reacting polyethylene glycol with tolylene-2,4-diisocyanate in presence of phosphorus pentachloride, benzene sulphonyl chloride, hydrogen chloride, p-methoxy benzoyl chloride, sulphuric acid or thionyl chloride is reacted with water in presence of a pyridine salt; (10) the polymer obtained by reacting polyethylene glycol with tolylene-2,4-diisocyanate in presence of benzenesulphonyl chloride is reacted with water in presence of a triethylamine salt; (11) and (12) the polymer obtained by reacting polypropylene glycol or poly-n-butylene glycol with tolylene-2,4-diisocyanate in presence of phosphorus trichloride is reacted with water in presence of a pyridine salt; (13) a polyalkylene glycol of formula HO(C2H4OCH2O)nH with a molecular weight of 1650 is heated with tolylene-2,4-di-isocyanate in presence of benzene sulphonyl chloride; the resultant polymer is reacted with water in presence of a pyridine salt; (14) the waxy polymer obtained from polyethylene glycol and tolylene-2,4-diisocyanate is reacted with water to give a sponge.