Treated inorganic pigments having reduced photoactivity and anti-microbial properties and their use in paper slurries
View Patent ↗The disclosure provides a paper slurry comprising a treated inorganic particle having reduced photoactivity and improved anti-microbial properties, wherein the treated inorganic pigment comprises: an inorganic core particle; a first treatment of a silicon compound, wherein the silicon compound is added in a single step; and a second treatment comprising a co-precipitated zinc oxide and alumina.
1. A paper slurry comprising a treated inorganic particle having reduced photoactivity and improved anti-microbial properties, wherein the treated inorganic particle comprises:
a. an inorganic core particle;
b. a first treatment of a silicon compound, wherein the silicon compound is added in a single step; and
c. a second treatment comprising a co-precipitated zinc oxide and alumina.
2. The paper slurry of claim 1 further comprising paper pulp.
3. The paper slurry of claim 1 wherein the inorganic core particle is ZnS, TiO 2 , CaCO 3 , BaSO 4 , ZnO, MoS 2 , silica, talc or clay.
4. The paper slurry of claim 3 wherein the inorganic core particle is titanium dioxide.
5. The paper slurry of claim 1 wherein treated inorganic particle is present in the amount of about 30 to about 90% by weight, based on the total weight of the paper slurry.
6. The paper slurry of claim 1 wherein the silicon compound is silica, zinc silicate or borosilicate.
7. The paper slurry of claim 6 wherein the silicon compound is silica.
8. The paper slurry of claim 7 wherein the silica is pyrogenically added silica.
9. The paper slurry of claim 7 wherein the silica is applied using wet treatment.
10. The paper slurry of claim 1 wherein the silicon compound is present in the amount of about 0.5 to about 20% by weight, based on the total weight of the inorganic core particle.
11. The paper slurry of claim 1 wherein the alumina is present in the amount of about 0.05% to about 20% by weight calculated as Al2O3 and based on the total weight of the inorganic core particle.
12. The paper slurry of claim 1 wherein the zinc oxide is present in the amount of about 0.3 to about 5% by weight, based on the total weight of the inorganic core particle.
13. The paper slurry of claim 1 wherein the titanium dioxide particle has a light stability of less than about 2.4.
14. The paper slurry of claim 1 wherein the metal oxide treatment further comprises oxides of phosphorus.
15. A décor paper prepared from a paper slurry, wherein the paper slurry comprises a treated inorganic particle having reduced photoactivity and improved anti-microbial properties, wherein the treated inorganic particle comprises:
a. an inorganic core particle;
b. a first treatment of a silicon compound, wherein the silicon compound is added in a single step; and
c. a second treatment comprising a co-precipitated zinc oxide and alumina.
16. The décor paper of claim 15 further comprising a melamine formaldehyde resin.
17. A laminate comprising a décor paper prepared from a paper slurry, wherein the paper slurry comprises a treated inorganic particle having reduced photoactivity and improved anti-microbial properties, wherein the treated inorganic particle comprises:
a. an inorganic core particle;
b. a first treatment of a silicon compound, wherein the silicon compound is added in a single step; and
c. a second treatment comprising a co-precipitated zinc oxide and alumina.
18. The laminate of claim 17 further comprising a Kraft paper core layer, a backing layer, and a melamine formaldehyde surface overlay.
19. The laminate of claim 18 comprising a ΔE* value of 6 or less after 72 hrs exposure in the referenced light cabinet.
20. The laminate of claim 19 comprising a ΔE* value of 2.4 or less after 72 hrs exposure in the referenced light cabinet.