| 摘要 |
1537202 Flame retardant polyurethane foam W R GRACE & CO 13 Jan 1977 [14 Jan 1976] 01360/77 Heading C3R A cross-linked flame-retardant polyurethane foam is prepared by a process which comprises mixing a polyurethane-forming prepolymer component which comprises an isocyanatecapped hydrophilic polyoxyethylene polyol defined below having an isocyanate functionality greater than two or, provided that a cross-linking agent having a functionality greater than two is included together with the prepolymer, equal to two, with an aqueous suspension containing alumina hydrate having an average particle size of from 0À5-120 microns, the proportion of said alumina hydrate being 50-400% wt., based on the weight of prepolymer component, and a suspending agent, to form a reaction mixture, and providing in the reaction mixture from 6À5 to 390 moles of available water per mole of NCO groups in the prepolymer. The foam may be produced by pouring or preferably spraying the reaction mixture into a mould. The polyoxyethylene polyol may have a weight average molecular weight of from 200 to 20,000 and an OH functionality of from 2-8, and is a homopolymeric adduct of ethylene oxide with a polyfunctional compound or a hydrophilic copolymeric adduct of ethylene oxide and a comonomer, such as propylene oxide or butylene oxide, with a polyfunctional compound, wherein said adducts have an OH functionality of at least 2 and an ethylene oxide content of from 40-100 mole per cent. Suitable cross-linking agents are monomeric polyamines and polyhydroxy compounds, hydrazine, ethanolamines and polycarboxylic acids. Inorganic or organic phosphorus-containing compounds may be included in the reaction mixture, many examples of which are given. The suspending agent may be a water-soluble or hydrophilic polymer, or an amphoteric, cationic or non-ionic surfactant, e.g. various celluloses, polyoxyethylene polymers, gelatin, guar gums, and agar; tallow amido alkyl sulphonic acid betaine, amine/fatty acid reaction products, quaternized ammonium fattychain salts; polyoxypropylene/ethylene oxide adducts, sorbitan monolaurate or trioleate, or polyoxyethylene sorbitan monolaurate or trioleate. A surfactant may also be present in the prepolymer component. The foam produced may be flexible, semi-rigid or rigid. In typical examples polyurethane foams are prepared by mixing a prepolymer component comprising tris-2,3-dibromopropyl phosphate, an N-difatty dimethyl quaternary ammonium chloride cationic surfactant and a prepolymer prepared from polyethylene glycol (M.Wt. = 1000), trimethylol propane and 80/20 2,4- and 2,6-tolylene diisocyanate with an aqueous mixture of alumina hydrate, water and either sorbitan trioleate non-ionic surfactant or hydroxyethyl cellulose, and then either pouring or spraying the resultant mixture into a mould. After curing the foam is placed in a microwave oven and then dried in a vacuum oven. |
