Patent attributes
The present disclosure relates to a process for making a decorative base paper for a paper laminate comprising impregnating a base paper with a pigment mixture of titanium dioxide and water wherein the titanium dioxide pigment is made by treating a mixture of titanium dioxide pigment and water with a source of phosphorus and a source of aluminum; drying the treated mixture to form a treated pigment, the treated pigment having surface hydroxyl groups; and removing a major proportion of the surface hydroxyl groups of the treated pigment. Preferably the surface hydroxyl groups are removed by thermal treatment, for example at temperatures ranging from 300° C. to 800° C. The source of phosphorus is typically phosphoric acid and the source of aluminum is typically sodium aluminate. The pigment can be characterized by an isoelectric point which is greater than pH 6 and a negative zeta potential of at least 20 mV at a pH of 7.5 or more and wherein the pigment has improved light fastness.
