Composition suitable for a powder coating composition comprising at least one resin and at least one dispersant
AssigneeDsm IP Assets B.V.
InventorsLeendert J. Molhoek, Jurjen H. M. Bolks, Jochum Beetsma
Life of this patent
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Abstract
Composition suitable for a powder coating composition comprising at least one resin and at least one dispersant wherein the dispersant is added during the resin synthesis or while the resin leaves the reactor.
Claims7
Process for the preparation of a powder coating composition having a glass transition temperature (Tg) at or above 20° C. and comprising (i) a resin having a Tg above 35° C. and functional groups through which the resin can react with a crosslinker, (ii) a crosslinker having functional groups which are able to react with the functional groups of the resin, (iii) a pigment powder, and (iv) a dispersant for dispersing the pigment powder in the powder coating composition, wherein the process comprises the steps of:
- (a) preparing the resin in a reactor;
- (b) adding the dispersant to the resin when the resin is in a liquid state at a temperature above the glass transition temperature (Tg) of the resin and at or below 270° C. just before the resin leaves the reactor or while the resin leaves the reactor in an amount of at least 0.01 to at most 10 w/w% based on the weight of dispersant in the resin to obtain a mixture of the resin and the dispersant;
- (c) solidifying the mixture of step (b);
- (d) mixing the pigment powder in an amount of more than 40 w/w% based on the weight of the powder coating composition and the crosslinker with the solidified mixture of step (c) to obtain a pigment-containing mixture;
- (e) homogenizing the pigment-containing mixture of step (d) to obtain a homogenized mixture;
- and
- (f) milling and sieving the homogenized mixture to obtain the powder coating composition.
Dependencies are inferred from the claim text.