Process for the preparation of pigment paste resins for cathodically depositable coating compositions having quaternized oxazolidine functional groups

摘要

Preparation of pigment paste resins for cathodically depositable coating compositions based on epoxy resin-amine adducts obtained from unmodified or modified epoxy resins, which by partial or complete reaction of secondary amino groups with formaldehyde contain oxazolidine structures; whose tertiary amino groups introduced via primary-tertiary diamines are quaternized to at least 20 mol % using an organic acid and a monoglycidyl compound and which in a solution adjusted with water to a correct application viscosity contain a total of 80 to 100 millimoles of acid per 100 g of solid resin are described. The pigment pastes possess, both in concentrated and dilute form, a stability which meets practical requirements and, because of their rheology, are readily processed to ensure formation of defect-free films both during deposition and crosslinking by stoving. The applied films have good properties.