A method for reducing water content of an epoxy or/and polyurethane paint dispersion and an epoxy or/and polyurethane paint dispersion

摘要

The invention relates to a method for reducing water content of an epoxy or/and polyurethane paint dispersion to be prepared in a sealed and pressurized aerosol can which paint dispersion comprises, -free water of an amount W1, -organic solvent(s) of an amount W2, -epoxy or/and polyurethane resin of an amount W3, -liquefied propellant of an amount W5, -ketone of an amount W6, -blocked hardener (hardener precursor) of the epoxy or/and polyurethane resin of an amount W4, wherein said blocked hardener compounds of said epoxy or/and polyurethane resin is selected from the group comprising of an aldimine, an enamine, an imine, a Mannich base, a Schiff’s base, an oxazolidine or a bisoxazolidine, and mixtures thereof, -adjuvants, -water scavenger(s), -catalytic amount of a weak acid to shift equilibrium of reversible reaction (I) between the free water present in said dispersion and blocked hardener compounds of the epoxy or/and polyurethane resin back to formation of said initial epoxy or polyurethane blocked hardener compounds and to prevent formation of the epoxy or/and polyurethane hardener amines: Epoxy and/or polyurethane hardener (amine) + Ketones - Catalyst - Epoxy and/or polyurethane precursor + Free water (1). The method comprises a step in which before providing organic solvent into the aerosol can its water content is reduced by admixing reactant with sulfonyl isocyanate functionality as a water scavenger into said organic solvent.