GB989921A - Polyether polyols and polyurethane foams derived therefrom - Google Patents

Abstract

The invention comprises poly(oxyalkylene) adducts of reduced oligasaccharides containing hexose units. Specified compounds are poly-(oxyethylene) maltitol, poly(oxypropylene) maltitol and poly(oxyethylene)-poly(oxypropylene) maltitol. Specified oligosaccharides are lactose, maltose, cellobiose, gentiobiose, isomaltose, planteobiose (6-O-a -D-galactopyramoxyl-D-fructose), turanose, melibiose, maltotriose, mannotriose and maltotetrose. Millet jelly and wheat gluten are also suitable starting materials. They may be reduced catalytically, e.g. using Raney nickel, or electrolytically. No purification of the reduced product is required. The whole of the alkylene oxide may be added at once or it may be added gradually. 7-29 moles of ethylene oxide or 5-22 moles of propylene oxide may be used per mole of reduced sugar giving OH numbers of 300-750. A block copolymer may be produced by adding one alkylene oxide followed by another. The reaction may be carried out at 90-150 DEG C. in the presence of a solvent and 0.01-0.5 equivalents of a basic catalyst per equivalent of hydroxyl group. Catalysts specified are the hydroxides, methoxides and ethoxides of sodium and potassium. Solvents specified are hydrocarbons, ethers, alkylamides, dimethyl sulphoxide, tertiary amines and nitrogen-containing heterocycles. Basic solvents may also function as catalysts. The reaction may be carried out in the presence of boron trifluoride and under a nitrogen atmosphere. If water is present in the sugar alcohol the initial addition of alkylene oxide will form a simple diol which can be distilled off prior to the main alkylene oxide addition. In Example (1) the alkylene oxide adduct was purified by neutralization with concentrated HCl, treatment with benzene, filtration and evaporation of volatile matter. In Examples (2) and (4) the product is passed down a carboxylic acid cation exchange resin.ALSO:Polyurethane foams may be produced by interacting a polyisocyanate, a blowing agent and a polyol derived by reducing an oligosaccharide composed of hexose units and treating it with ethylene oxide and/or propylene oxide. Oligosaccharides specified are: lactose, maltose, cellobiose, gentiobiose, isomaltose, planteobiose (6-O-a -D-galactopyranosyl-D-fructose), turanose, melibiose, maltotriose, mannotriose and maltotetrose. Millet jelly and wheat gluten may also be used. They may be reduced catalytically, e.g. using Raney Ni or electrolitically. Treatment of the reduced sugar with alkylene oxide may be at 90-150 DEG C. 7-29 moles of ethylene oxide or 5-22 moles of propylene oxide may be used per mole of reduced sugar. A block copolymer may be produced by adding one alkylene oxide followed by the other. The reaction may be catalyst by 0.01-0.5 equivalents per functional OH group of sodium or potassium hydroxide, methoxide or ethoxide. Solvents specified are: n-hexane, ligroin, benzene, xylene, dioxane, diethylene glycol diethyl ether, dimethyl formamide, dimethyl sulphoxide, N - acylmorpholines, N - methylpyrrolidone, N - ethyl pyrrolidone, pyridine, piccoline, quinoline, tri-n-butylamine. The amines can act as catalysts as well as solvents. The reaction may be carried out in the presence of BF3 and under an N2 atmosphere. If water is present in the sugar alcohol the initial addition of alkylene oxide will form a diol which may be distilled out prior to the main alkylene oxide addition. The products of this stage may have OH numbers of 300-750. In preparing polyurethanes these polyols may be mixed with straight chain polyethers, polyester polyols or polyethers of phenol resins or sorbitols. Polyisocyanates specified are: 1 : 1- and 1 : 2-ethylene, 1,2-propylene, 1,2-butylene, 1,6-hexylene, 1,2-cyclohexylene, and m-phenylene diisocyanates, tolylene - 2,4 - and 2,6 - diisocyanates, diphenylene-4,41-diisocyanate, and its 3,31-dimethyl -, 3,31 - dimethoxy - and 3,31-dichloro-derivatives, tris(p-isocyanatophenyl)-methane, naphthalene-1,5-diisocyanate and derivatives thereof with 1,2,6-hexane triol, trimethylol propane, glycerol, and mono-, di- and tri-ethylene and propylene glycols. Blowing agents specified are water, CCl2F2, CCl3F and azo compounds. Catalysts specified for the polyurethane forming reaction are: N-methyl-morpholine, triethylamine, N,N,N1,N1-tetramethyl - 1,3 - butanediamine, N,N,N1,N1 - tetrakis (2 - hydroxypropyl)ethylenediamine, dimethyl ethanolamine, dibutyltin dilaurate, dibutyltin di(2-ethylhexoate), stannous octoate, stannous 2-ethylhexoate. Other additives may be silicon oil foam stabilizers, e.g. polydimethylsiloxane and alkyl silane/polyoxyalkylene CO-polymers, nonionic surface-active agents, e.g. sorbitan monostearate and glycerol mono-oleate, pigments, fillers, e.g. glass fibres, nylon fibres, wool, polyvinyl chloride, mica, alumina gel, silica gel, asbestos and zinc oxide, antioxidants, and stabilizers. The foam may be prepared by a prepolymer or one-step method and may be rigid.