Process for making a décor paper having improved optical performance
View Patent ↗A décor paper is prepared from a dispersion having improved optical performance, wherein the dispersion contains a TiO 2 particle slurry; paper pulp; and a cationic polymer. The TiO 2 particle slurry has a treated TiO 2 particle with a surface area of at least about 30 m 2 /g and a cationic polymer; the treatment is an oxide of silicon, aluminum, phosphorus or mixtures thereof; and the treatment is present in the amount of at least 15% based on the total weight of the treated titanium dioxide particle. Comparable dispersions not using the TiO 2 particle slurry described would require about 10% more treated TiO 2 particle than a dispersion made with the described TiO 2 particle slurry, paper pulp, and cationic polymer to achieve equivalent optical performance. These décor papers are useful in preparing paper laminates.
1. A process for making a décor paper from a dispersion with improved optical performance, comprising the steps:
(a) combining a treated TiO 2 particle having a surface area of at least about 30 m 2 /g with water and a first cationic polymer to form a TiO 2 particle slurry;
wherein the treated TiO 2 particle comprises an oxide selected from the group consisting of silicon, aluminum, phosphorus and mixtures thereof; and the oxide is present in the amount of at least 15% based on the total weight of the treated titanium dioxide particle;
(b) combining the TiO 2 particle slurry of step (a) with paper pulp and a second cationic polymer;
wherein for equal optical performance, the amount of treated TiO 2 particle in the dispersion is reduced by about 10% when compared to the same dispersion not comprising the TiO 2 particle slurry of (a).
2. The process of claim 1 wherein the treated TiO 2 particle is a pigment.
3. The process of claim 1 wherein the first cationic polymer is a urea-formaldehyde resin, a melamine-formaldehyde resin, a cationic polyacrylamide polymer, a polydialkyllammonium polymer, a polyacrylamide-polydialkylammonium copolymer, or a polyamide-polyamine-epichlorhydrin resin.
4. The process of claim 1 wherein the second cationic polymer is a urea-formaldehyde resin, a melamine-formaldehyde resin or a polyimide-polyamine-epichlorhydrin resin.
5. The process of claim 1 wherein the oxide is silicon oxide that is present in an amount of at least about 6% by weight, based on the total weight of the treated TiO 2 pigment.
6. The process of claim 5 wherein the silicon oxide is applied by deposition of pyrogenic silica onto a pyrogenic TiO 2 particle, co-oxygenation of silicon tetrachloride with titanium tetrachloride or by deposition via condensed phase aqueous oxide.
7. The process of claim 6 wherein the silicon oxide is applied by deposition via condensed phase aqueous oxide.
8. The process of claim 6 wherein the silicon oxide is substantially homogenous on the surface of the TiO 2 particle.
9. The process of claim 5 wherein the silicon oxide is applied by deposition via condensed phase aqueous oxide.
10. The process of claim 1 wherein the oxide is aluminum oxide that is present in an amount of about 4 to about 8%, based on the total weight of the treated TiO 2 pigment.
11. The process of claim 1 wherein the TiO 2 particle has a particle size of about 0.02 to about 0.95 microns.
12. The process of claim 1 wherein the TiO 2 particle has a particle size of about 0.5 to about 0.75 microns.
13. The process of claim 1 wherein the TiO 2 particle is a pyrogenic TiO 2 particle.
14. The process of claim 1 wherein the second cationic polymer is present in the amount of about 0.5 to about 1.5% by weight, based on the total dry weight of the pulp used in the paper.