Patent GB-898530-A (GB)
Title: Polyether-urethane rubber
Inventor: PRICE CHARLES COALE
IPC: C08G18/48
Filed: 1958-08-26
Abstract: A process of preparing a polyurethane elastomer comprises reacting initially in the liquid state a hydroxy-terminated polyalkylene ether glycol having a molecular weight of 600 which is a condensation product derived from (a) an alkylene oxide having 3 or more carbon atoms or a mixture of alkylene oxides at least 15% of which comprises an alkylene oxide having 3 or more carbon atoms and (b) from 0,01 to 5 mol. per cent preferably from 1 to 5 mol. per cent based on the alkylene oxide of a polyhydric alcohol having from 3 to 6 hydroxy groups, with an organic isocyanate having 2 or 3 functional isocyanate groups and continuing the reaction until an elastomer is produced.  To obtain the product in the form of a sponge the reaction is effected in the presence of a tertiary amine catalyst and a small amount of water and curing is effected during the reaction to entrap the carbon dioxide produced.  Specified polyhydric alcohols are glycerol, hexanetriol-1,2,6; trimethylolpropane and pentaerythritol. Solid, non-porous rubbers are obtained from approximately equimolecular amounts of the polyglycols and diisocyanates.  Foams are obtained by using a 1,1:1 to 12:1 equivalent weight ratio of polyisocyanate to polyglycol.  In typical examples (1) an elastomer is obtained by reacting 1 mol. of propylene oxide and 0,05 mol. of pentaerythritol in the presence of sodium, dissolving the product in alphachloro naphthalene and adding toluene diisocyanate; (2) a viscous polymer from the reaction of propylene oxide and pentaerythritol in the molar ratio 100:1 is mixed with 2,4-tolylene diisocyanate, water, triethylamine and silicone oil and reacted to give a foam.ALSO:A hydroxy terminated polyalkylene ether polyol, for use in the preparation of polyurethanes (see Group IV (a)) is prepared by condensing (a) an alkylene oxide having 3 or more carbon atoms or a mixture of alkylene oxides at least 15% by weight of which comprises an alkylene oxide having 3 or more carbon atoms with (b) from 0.01 to 5 mol. per cent., based on the alkylene oxide, of a polyhydric alcohol having from 3 to 6 hydroxyl groups.  Suitable polyhydric alcohols are glycerol, hexanetriol-1,2,6-trimethylol propane and pentaerythritol.  In examples polyalkylene ether polyols are obtained by reacting (1) and (2) 1 mol. of propylene oxide and 0.05 mol. of pentaerythritol in the presence of sodium or sodium alcoholate; (3) 85 parts of propylene oxide and 15 parts of ethylene oxide with less than 5 mols. per cent. of trimethylol propane; (3) 1 mol. of glycerol with 60 mols. of propylene oxide, followed by 2 to 4 mols. of ethylene oxide to provide primary hydroxyl terminal end groups.ALSO:A process of preparing a polyurethane elastomer comprises reacting initially in the liquid state a hydroxy-terminated polyalkylene ether glycol having a molecular weight of 600 which is a condensation product derived from (a) an alkylene oxide having 3 or more carbon atoms or a mixture of alkylene oxides at least 15% of which comprises an alkylene oxide having 3 or more carbon atoms, and (b) from 0,01 to 5 mol per cent. (preferably from 1 to 5 mol per cent.) based on the alkylene oxide of a polyhydric alcohol having from 3 to 6 hydroxy groups, with an organic isocyanate having 2 or 3 functional isocyanate groups and continuing the reaction until an elastomer is produced.  To obtain the product in the form of a sponge the reaction is effected in the presence of a tertiary amine catalyst and a small amount of water and curing is effected during the reaction to entrap the carbon dioxide produced.  Specified polyhydric alcohols are glycerol, hexanetriol-1, 2, 6; trimethylol-propane and pentaerythritol.  Solid, non-porous rubbers are obtained from approximately equimolecular amounts of the polyglycols and diisocyanates.  Foams are obtained by using a 1,1: 1 to 12: 1 equivalent weight ratio of polyisocyanate to polyglycol.  In typical examples (1) an elastomer is obtained by reacting 1 mol of propylene oxide and 0,05 mol of pentaerythritol in the presence of sodium, dissolving the product in alphachloro naphthalene and adding toluene diisocyanate; (2) a viscous polymer from the reaction of propylene oxide and pentaerythritol in the molar ratio 100: 1 is mixed with 2, 4-tolylene diisocyanate, water, triethylamine and silicone oil and reacted to give a foam.