Patent GB-846176-A (GB)
Title: Weather and age resistant polyurethane compositions
IPC: C08G18/76
Filed: 1958-05-13
Abstract: A method of preparing an age and weather resistant composition comprises mixing and reacting (1) about 0,5 mols to about 12 mols of a polyisocyanate of the general formula (OCNR)n-Ar-(Z)y where n is 2 or 3, R is an alkylene group of 2 to 5 carbon atoms, Ar is an aromatic ring system and Z is a group attached directly to the aromatic ring system and is hydrogen, halogen, nitrile, an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms or a <FORM:0846176/IV(a)/1> group where B is an alkyl group of 1 to 4 carbon atoms and y is an integer less than 8, the maximum depending of course on the particular aromatic ring system involved, with (2) one mol of a hydroxy terminated polyol having a molecular weight of at least 500.  The reaction may be effected with a mixture of the above polyisocyanates with other polyisocyanates.  The method can be applied to the production of coatings, foams and elastomers. "Polyol" denotes an aliphatic compound with a long chain molecular structure, a molecular weight of at least 500 and terminal hydroxyl groups containing active hydrogen.  Examples are polyethylene adipate and polytetramethylene ether glycol, alkyd resins (which may be modified by, for example, castor oil), and reaction products of polycarboxylic acids with polyols of the formula HO-(RO)n -OH where n is 1 to 50 and R is an adiphatic group.  Mixed polyether and polyester can be used. Foams are obtained by reaction of an isocyanate with water or carboxyl groups, by gasifying the reaction mixture at high pressure or by introducing CO2 or "Freon" (Registered Trade Mark).  A prepolymer may first be produced for subsequent foaming.  The foam is poured into moulds containing upright cylindrical pegs.  For foams the polyisocyanate:polyol ratio is preferably from about 8:1 to about 4:1.  For coating the ratio is preferably about 1:1 to about 3:1. The polyol and polyisocyanate may be mixed in a solvent, applied to a surface and polymerised by heating.  In Examples there are prepared (1) a coating composition of p-phenylene-2,21-bis (ethyl isocyanate) and a castor oil modified alkyd dissolved in butyl acetate and xylene; (2) and (3) foams from (2) an adipic acid/diethylene glycol/trimethylolpropane polyester, phenylene 1,3 bis ethylene diisocyanate and an aqueuous mixture of diethylethanolamine adipate and diethylamine oleate; (3) a polytetramethylene ether glycol/p-phenylene-2,21-bis(ethyl isocyanate) prepolymer and silicone oil, water and N-methyl morpholine; (4) a composition of a polyethylene propylene adipate reacted with 2-methyl 1,4-phenylene bis (butyl isocyanate) and milled with white pigment, calcium carbonate and a curing agent.  Comparative results with other polyisocyanates are given.ALSO:A method of preparing an age and weather resistant composition comprises mixing and reacting (1) about 0,5 mols to about 12 mols of a polyisocyanate of the general formula (OCNR)n-Ar-(Z)y where n is 2 or 3, R is an alkylene group of 2 to 5 carbon atoms, Ar is an aromatic ring system and Z is a group attached directly to the aromatic ring system and is hydrogen, halogen, nitrile, an alkyl group of 1 to 4 carbon atoms, an alkoxy group of 1 to 4 carbon atoms or a <FORM:0846176/V/1> group where B is an alkyl group of 1 to 4 carbon atoms and y is an integer less than 8, the maximum depending of course on the particular aromatic ring system involved, with (2) one mol of a hydroxy terminated polyol having a molecular weight of at least 500.  The reaction may be effected with a mixture of the above polyisocyanates with other polyisocyanates. The method can be applied to the production of coatings, foams and elastomers. "Polyol" denotes an aliphatic compound with a long chain molecular structure, a molecular weight of at least 500 and terminal hydroxyl groups containing active hydrogen.  Examples are polyethylene adipate and polytetramethylene ether glycol, alkyd resins (which may be modified by, for example, castor oil), and reaction products of polycarboxylic acids with polyols of the formula HO-(RO)n-OH where n is 1 to 50 and R is an aliphatic group.  Mixed polyether and polyester can be used.  Foams are obtained by reaction of an isocyanate with water or carboxyl groups, by gasifying the reaction mixture at high pressure, or by introducing CO2 or "Freon" (Registered Trade Mark).  A prepolymer may first be produced for subsequent foaming.  The foam is poured into moulds containing upright cylindrical pegs.  For foams the polyisocyanate: polyol ratio is preferably from about 8 : 1 to about 4 : 1.  For coating the ratio is preferably about 1 : 1 to about 3 : 1.  The polyol and polyisocyanate may be mixed in a solvent, applied to a surface and polymerised by heating.  In Examples there are prepared (1) a coating composition of p-phenylene-2, 21-bis (ethyl isocyanate) and a castor oil modified alkyd dissolved in butyl acetate and xylene; (2) and (3) foams from (2) an adipic acid/diethylene glycol/trimethylolpropane polyester, phenylene 1, 3 bis ethylene diisocyanate and an aqueous mixture of diethlethanolamine adipate and diethylamine oleate; (3) a polytetramethylene ether glycol/p-phenylene -2, 21-bis (ethyl isocyanate) prepolymer and silicone oil, water and N-methyl morpholine; (4) a composition of a polyethylene propylene adipate reacted with 2-methyl 1, 4-phenylene bis (butyl isocyanate) and milled with white pigment, calcium carbonate and a curing agent. Comparitive results with other polyisocyanates are given.