| abstract |
Polyurethane foams are prepared by reacting an organic polyisocyanate in the presence of a blowing agent, with a polyhydric polyalkylene ether prepared by effecting polymerization of one or more ethylenically unsaturated monomers in situ in a polyhydric polyalkylene ether. The polyhydric polyalkylene ether may be substantially linear and have a M.W. of 400-5000 and a hydroxyl content of 0.5-15%. Suitable ethers may have graft polymers and/or mixtures of ethylenically unsaturated monomers dissolved in or bonded to the ether. Unsaturated monomers may be: aromatic vinyl compounds, e.g. styrene, olefines, e.g. ethylene, propylene, 1-butylene, 2-hexene, 1,4-hexadiene, 1,3-butadiene, 3-pentene, vinyl esters, e.g. vinyl acetate or propionate, vinyl chloride, vinylidene chloride, arcyclic and methacrylic acids, acrylonitrile, polyvinyl compounds, e.g. triallyl cyanurate and glycol dimethyl acrylate. Suitable polyhydric polyalkylene ethers are those obtained by condensation of ethylene oxide, propylene oxide, 1,2- and 1,3-butylene oxide, styrene oxide, epichlorohydrin and tetrahydro furan. These alkylene oxides may be condensed with polyhydric alcohols and amines. The monomer is preferably used in amount 1-60% by weight and the polymerization is preferably effected in the absence of oxygen with an initiator, e.g. organic oxide or azo compound, or redox systems, e.g. benzoyl peroxide-diethyl toluidine and ferrous-ferric iron systems, or high energy radiation. The polyhydric polyalkylene ethers containing the polymerizate may be used in admixture with other compounds containing active hydrogen atoms, e.g. linear or branched polyesters and polyesteramides, unmodified polyhydric polyalkylene ethers and reaction products of amino alcohols, diamines, hydroxyamines with alkylene oxides or carboxylic acids. In a typical Example (1) vinyl chloride was polymerized in the presence of linear polypropylene glycol of M.W. 2000 and benzoyl peroxide and the thus modified polyether reacted with tolylene diisocyanate in the presence of triethylene diamine, dibutyltin dilaurate, polysiloxane and water to form a foamed polyurethane. |