Patent ID: 8318853

Claim:
A method of coating a substrate comprising the steps of (a) providing a composition of positively- or negatively- charged or chargeable solid or liquid particulates; (b) combining the composition with one or more thermally-responsive dispersants in association with an aqueous dispersing medium, and optionally a binder, to form a coating composition containing an aqueous dispersion comprising the positively- or negatively- charged or chargeable solid or liquid particulates and the thermally-responsive dispersant, wherein the thermally responsive dispersant comprises a compound having an anchoring moiety linked to at least one thermally-responsive polymeric stabilizing moiety, other than a polyalkylene oxide, the at least one polymeric moiety having a lower affinity for the surface than the anchoring group below the thermal transition temperature, the particulates being positively- charged or chargeable when the anchoring moiety contains at least one acid and/or hydroxy group and has a net acidity or neutrality and the particulates being negatively- charged or chargeable when the anchoring moiety has at least one basic group and has a net basicity, wherein the dispersion exhibits a change in sign from negative to positive and an increase in magnitude of a rheological property, the property being viscosity at low shear and/or complex modulus at low amplitude oscillatory shear, on increasing the temperature from below to above the thermal transition temperature; (c) applying the coating composition to the substrate at a temperature below the thermal transition temperature of the dispersant to form a fluid coating thereon; and (d) drying the resultant coating at a temperature above the transition temperature of the dispersant by the application of heat.