| 摘要 |
<p>1521326 Blocked polyisocyanates BAYER AG 30 Oct 1975 [29 Nov 1974] 44902/75 Heading C3R Water-soluble or water-dispersible blocked polyisocyanates suitable for use in the production of polyurethanes are prepared by blocking from 50 to 99À8% of the isocyanate groups of an organic polyisocyanate by reaction with a blocking agent and reacting the resulting partially blocked polyisocyanate with a compound which contains at least one isocyanatereactive hydrogen atom and either at least one hydrophilic group or at least one group convertible to ahydrophilic group and being selected from aliphatic hydroxy carboxylic acids, aliphatic or aromatic aminocarboxylic acids, aliphatic hydryoxy sulphonic acids and aliphatic or aromatic aminosulphonic acids having a M.W. below 300 and alkali metal salts of these acids, tertiary amines having an aliphatically bonded hydroxyl group and a M.W. below 300 and monohydroxy polyalkylene oxides having a M.W. of from 500 to 5,000 of the type which may be obtained by alkoxylating a monofunctional starter molecule, and from 50 to 100% of whose polyalkylene oxide chain is made up of ethylene oxide units. In conjunction with water-soluble or water-dispersible compounds containing isocyanate-reactive atoms, aqueous solutions or dispersions of the blocked polyisocyanates may be used for the production of coatings, films and impregnations.</p> |
