Patent GB-801023-A (GB)
Title: Improvements in or relating to polyurethane elastomers
IPC: C08G18/81
Filed: 1956-07-23
Abstract: The invention comprises polymeric polyurethanes consisting essentially of the recurring structural units <FORM:0801023/IV (a)/1> wherein -O-G-O- is a bivalent radical resulting from the removal of the terminal hydrogen atoms from a polymeric glycol having a molecular weight of at least 750 and consisting of a polyalkylene ether glycol, a polyalkylene-ether-thioether glycol, a polyalkylene-arylene-ether glycol or a polyalkylene-arylene-ether-thioether glycol; B is a bivalent organic radical inert to isocyanate groups; -O-R-O- is a bivalent radical resulting from removal of the terminal hydrogen atoms from a non-polymeric glycol having a molecular weight below 300; n is an integer greater than zero; m is an integer or zero; each of the structural units being connected to the next by either of the radicals <FORM:0801023/IV (a)/2> and <FORM:0801023/IV (a)/3> wherein -O-G-O- and -O-R-O- have the significance defined above; with at least 60 per cent of the total weight of the polymer being the bivalent radicals O-G-O and with the proviso that at least one of the bivalent radicals O-G-O, B and -O-R-O- has a side chain containing an aliphatic C=C group, said side chain occuring at least once for every 8000 units of molecular weight of the polymeric polyurethane.  The polymers can be prepared by reacting the glycols together or successively with an organic diisocyanate, the overall ratio of the diisocyanate to the sum of the polymeric and non-polymeric glycols being substantially equimolecular.  Alternatively, the bis-chloroformates of the polymeric glycol and of the non-polymeric glycol may be reacted with a substantially equimolar amount of a diamine.  Isocyanates specified are toluene-2 : 4-diisocyanate, m-phenylene diisocyanate, 4-chloro-1 : 3-phenylene diisocyanate, 4,41-biphenylene diisocyanate, 1 : 5-naphthylene diisocyanate, 1 : 4-tetramethylene diisocyanate, 1 : 6-hexamethylene diisocyanate, 1 : 10-decamethylene diisocyanate, 1 : 4-cyclohexylene diisocyanate, 4 : 41 - methylene - bis - (cyclohexylisocyanate), and 1 : 5-tetrahydronaphthylene diisocyanate.  As non-polymeric glycols (containing aliphatic C=C groups) there are specified 4-methyl-3-cyclohexene - 1 : 1 - dimethanol, 3 - cyclohexene-1 : 1 - dimethanol, 3 - allyloxy - 1 : 5 - pentanediol, 3-(allyloxy)-1 : 2-propanediol, 2-[(allyloxy)-methyl] - 2 - methyl - 1 : 3 - propanediol, 2-vinyl - 1 : 3 - propanediol, 3 - (2 - methallyloxy)-1 : 2 - propanediol, 2 : 21 - (4 - allyl - m - phenylenedioxy) - diethanol, 3 - (4-allyl - 2 - methoxyphenoxy) - 1 : 2 - propanediol, 3 - (o - allylphenoxy) - 1 : 2 - propanediol, 2 - methyl - 2 - [(4-pentenyloxy) - methyl] - 1 : 3 - propanediol, 2-[(allyloxy) - ethyl] - 2 - methyl - 1 : 3 - propanediol, 2 - methyl - 2 - [(10 - undecenyloxy) methyl] - 1 : 3 - propanediol, 2 : 21 - (allylimino)-diethanol, 2 - [(3 - methylallyloxy) methyl)-2-methyl - 1 : 3 - propanediol, 2 - [(allyloxy)-methyl] - 1 : 3 - propanediol, 3 - (o - propenylphenoxy) - 1 : 2 - propanediol and 3 - (4 - allyl-2-methoxy - phenoxy) - 1 : 2 - propanediol.  Preferred are 1 : 3-propane diols of the formula <FORM:0801023/IV (a)/4> where x is a hydrocarbon radical with a terminal -CH=CH2 group.  The polymeric polyurethane products can be cured by sulphurcuring.  In examples: (1) a mixture of polytetramethylene-ether glycol (M.Wt. 953) and 4 - methyl - 3 - cyclohexene - 1 : 1 - dimethanol is reacted at 80-85 DEG C. with toluene-2 : 4-diisocyanate and the reaction mixture heated in a mould to give a polymer (soluble in a mixture of tetrahydrofuran and dimethyl formamide).  The polymer is milled with channel black, zinc oxide, sulphur, 2-mercapto-benzothiazole and tetramethyl thiuram disulphide and moulded and cured under heat and pressure; (2) 3-(allyloxy) - 1 : 2 - propanediol containing phenyl - b  - naphthylamine as an antioxidant is reacted with excess toluene-2 : 4-diisocyanate and the product is reacted with tetramethylene-ether glycol to give a polymer, e.g. in presence of pyridine as a catalyst. The polymer is milled with furnace black, sulphur, 2-mercaptobenzothiazole, 2,21 - dithiobisbenzothiazole and zinc chloride and cured in a mould under heat and pressure; (3) 3-(methallyloxy)-1 : 2-propanediol and toluene-2 : 4-diisocyanate are reacted to form a bis-urethane with -OH end groups.  This is reacted with excess toluene-2 : 4-diisocyanate and the product is heated with polytetramethylene-ether glycol to give a polymer.  The polymer is milled with carbon black, zinc oxide, sulphur, stearic acid, mecaptobenzthiazole and tetramethyl thiuram disulphide and heated in moulds.  In further examples, polymers are prepared by reacting together (4) a mixture of polytetramethylene-ether glycol, 4 - methyl - 3 - cyclohexene - 1 : 1 - dimethanol and 3 : 31 - dimethyl - 4 : 41 - biphenyl diisocyanate; (5) a product prepared from 3-(allyloxy)-1 : 2-propanediol and excess toluene-2 : 4-diisocyanate and a polyurethane prepared from polytetramethylene ether glycol (3 mols.) and toluene-2 : 4-diisocyanate (2 mols.); (6) and (7) toluene-2 : 4-diisocyanate, 2-(allyloxy)-1 : 3-propenediol and polytetramethylene-ether glycol; (8) 2 - [(allyloxy) - methyl] - 2 - methyl - 1 : 3 - propanediol, polytetramethylene-ether glycol and toluene-2 : 4-diisocyanate; (9) polytetramethylene-ether glycol, 2 : 21-(allylimino)-diethanol and toluene-2 : 4-diisocyanate; (10) 2 : 21 - (4 - allyl - m - phenylenedioxy) - diethanol, toluene-2 : 4-diisocyanate and polytetramethylene glycol; (11) 3-(o-allylphenoxy)-1 : 2-propanediol, toluene-2 : 4-diisocyanate and polytetramethylene-ether glycol; (12) 3-(4-allyl-2-methoxyphenoxy) - 1 : 2 - propanediol, toluene-2 : 4-diisocyanate and polytetramethylene-ether glycol; (13) 3 - (o - propenylphenoxy)-1 : 2 - propanediol, toluene - 2 : 4 - diisocyanate and polytetramethylene ether glycol.  The polymers obtained are cured with sulphur-vulcanization agents, zinc p-methoxydithiocarbonilate being an additional ingredient added to the polymer before curing in Examples (8) and (11) to (13).