MODIFIED EPOXY RESIN AND ITS USE AS A FORMULATING COMPONENT FOR HEAT-CURABLE COMPOSITIONS, ESPECIALLY FOR POWDER COATINGS

摘要

Epoxy resins which are obtainable by a process in which, first of all (a) by reacting (A1) at least one substance selected from the substances of formula (I) and of formula (II) in which Alc is the radical of a diol which has been freed from its hydroxyl groups and comprises 2 to 20 carbon atoms, Ac is the radical of a dicarboxylic acid which has been freed from its carboxyl groups and comprises 2 to 20 carbon atoms, [Ph] is the radical of a difunctional phenolic compound which has been freed from its phenolic hydroxyl groups and has 6 to 20 carbon atoms, and c is a number greater than 1 but not more than 2, with (A2) at least one liquid diglycidyl ether based on a first bisphenol compound in an amount chosen so that there are more than two equivalents of glycidyl groups of component (A2) for a total of one equivalent of carboxyl and phenolic hydroxyl groups of component (A1), a pre-advanced diglycidyl ether resin is formed in dispersion in the liquid diglycidyl ether of which there is at least one, and subsequently (b) the resin dispersion obtained in accordance with (a) is reacted with a phenol component comprising at least one bisphenol compound which is identical to or different from the first bisphenol compound, the amount of the phenol component being chosen so that in the mixture of the resin dispersion and the phenol component the glycidyl groups prior to the reaction are in a stoichiometric excess over the phenolic hydroxyl groups have an advantageously low melt viscosity and are suitable as a formulating component for heat-curable compositions, especially for powder coating materials.