Production of emulsifiable polyisocyanate for use in aqueous coating material or adhesive, involves reacting di-isocyanate with polyether-alcohol and mixing the product with aliphatic polyisocyanate and allophanatisation catalyst

摘要

A method for the production of water-emulsifiable polyisocyanate preparations by (A) reacting di-isocyanates with polyether-alcohols to form products (E) with dispersant properties and then (B) mixing (E) with aliphatic polyisocyanates, involves forming allophanate groups by carrying out stage (B) in presence of an allophanatisation catalyst. A two-stage method for the production of water-emulsifiable polyisocyanate preparations (I) involves (A) making a reaction product (E) with dispersant properties from di-isocyanate(s) selected from tetramethylene-, hexamethylene- or dodecamethylene-di-isocyanate, 1,4-di-isocyanatocyclohexane, 4,4-di-(isocyanatocyclohexyl)-methane, trimethylhexanedi-isocyanate, tetramethylhexanedi-isocyanate, isophoronedi-isocyanate, 2,4- or 2,6-toluenedi-isocyanate, tetramethylxylylenedi-isocyanate, p-xylylenedi-isocyanate and/or 2,4- or 4,4-di-isocyanatodiphenylmethane together with mono- or poly-hydric poly(2-4C alkylene-ether-alcohols) and then (B) mixing (E) with aliphatic polyisocyanate(s) with an average NCO functionality of 2.5-3.5. Stage (B) is carried out in presence of an allophanatisation catalyst under suitable conditions for the formation of allophanate groups between (E) and the polyisocyanate. An independent claim is also included for water-emulsifiable polyisocyanate preparations (I) obtained by this method.