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Method of obtaining a flexible foam of polyurethane, by reacting a diisocyanate, on a polyether polyol and of the water
Method of obtaining a flexible foam of polyurethane, by reacting a diisocyanate, on a polyether polyol and of the water
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机译:通过使二异氰酸酯与聚醚多元醇和水反应获得聚氨酯软质泡沫的方法
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摘要
Polyurethane foam is prepared by admixing (a) a diisocyanate, (b) a mixture of polyether polyols consisting of 50 to 90% by weight of a polyoxyalkylene triol having a molecular weight of 1000 to 5000 and an -OH number of 30 to 170 and 10 to 50% by weight of a polyoxyalkylene diol having a molecular weight of 1000 to 3000 and an -OH number of 40 to 110, the mixture having a primary hydroxyl group content of 10 to 65% and (c) water. Suitable diisocyanates (a) are m-phenylene diisocyanate, 2,4- and 2,6-tolylene diisocyanates, naphthalene 1,5- and naphthalene 1,8-diisocyanates, 4,41-methylene - bis - (phenylisocyanate), 4,41-methylene - bis - (tolylisocyanate) 4,41 - methylene - bis - (cyclohexylisocyanate) and 1,6-hexamethylene diisocyanate. A mixture of polyoxyalkylene triols and diols is utilized at least one of which preferably contains terminal hydroxyethylene or hydroxypropylene groups and which is preferably prepared by using 1,2-propylene oxide or a mixture of 1,2-propylene oxide and ethylene oxide in the initial condensation and thereafter to condense ethylene oxide or less preferably 1,3-propylene oxide with the initial condensation product to provide terminal hydroxyalkylene groups and primary hydroxyl groups in the required amount. The preferred polyoxypropylene triol has a primary hydroxyl content of 25 to 50% and the preferred polyoxypropylene diol has a primary hydroxyl content of 0 to 30%. Auxiliary blowing agents such as fluorocarbons, catalysts such as tertiary amines, organo-tin compounds and organic tin salts, and dispersing agents such as silicone-oxyalkylene block copolymers may also be incorporated into the foam forming reaction mixture. At least 5% of a filler having a particle size of below 50 microns in the largest dimension may also be incorporated into the reaction mixture. Barium sulphate is the preferred filler.
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