Isocyanate core shell rubber modified epoxy resin having high glass transition temperature and advanced rust-resisting properties and its preparing method and powdered paint composition contained thereof

摘要

PURPOSE: An isocyanate core-shell rubber modified multifunctional epoxy resin for a powered paint, its preparation method and a powdered paint composition containing the resin are provided to increase a glass transition temperature and to improve corrosion resistance and flexibility. CONSTITUTION: The method comprises the steps of dispersing 1-20 parts by weight of a core-shell rubber having a particle size distribution of 300-20,000 Angstrom to 100 parts by weight of a low molecular weight epoxy resin having a molecular weight of 350-400 to prepare a core-shell rubber modified epoxy resin; reacting 100 parts by weight of the core-shell rubber modified epoxy resin with 10-30 parts by weight of a novolac epoxy resin and 0-0.5 parts by weight of a catalyst to a novolac epoxy modified resin with improved functional groups; and reacting the novolac epoxy modified resin with 1-30 parts by weight of an isocyanate compound based on 100 parts by weight of the novolac epoxy modified resin and 0.01-0.5 parts by weight of a catalyst based on 100 parts by weight of the isocyanate compound, to obtain an isocyanate core-shell rubber modified multifunctional epoxy resin having a number average molecular weight of 500-2,000, an epoxy equivalence of 250-800 g/eq, a softening point of 90-130 deg.C and a viscosity of 10-40 poise (175 deg.C).