CA2385878A1

CA2385878A1 - Recording medium with glossy coating containing alumina

Info

Publication number: CA2385878A1
Application number: CA002385878A
Authority: CA
Inventors: Michael S. Darsillo; David J. Fluck; Rudiger Laufhutte
Original assignee: Individual
Current assignee: Cabot Corp
Priority date: 1999-10-01
Filing date: 2000-09-26
Publication date: 2001-04-12
Anticipated expiration: 2020-09-26
Also published as: EP1238157B1; AU7718900A; DE60039189D1; WO2001025534A1; EP2096208A1; JP4805504B2; BR0014304A; ATE398208T1; JP2003511266A; EP1238157A1; ATE535646T1; CA2385878C; EP2096208B1

Abstract

The present invention provides a recording medium comprising a substrate having a glossy coating thereon, wherein the glossy coating comprises a bind er and alumina particles that are aggregates of primary particles. The present invention further provides a coating composition comprising the aforesaid alumina particles and a binder, wherein the solids content of the alumina in the coating composition is at least about 10 wt. %. The present invention al so provides a method of preparing a coating composition, which method comprises providing a colloidally stable dispersion of the aforesaid alumina particles , wherein the solids content is greater than about 20 wt. %; adding a binder t o and, optionally, diluting the dispersion; and, optionally, adjusting the pH with a suitable acid or base. The present invention further provides a metho d of preparing a recording medium, which method comprises providing a substrat e, coating the substrate with the coating composition of the present invention, optionally calendering the coated substrate, and drying the coated substrate .

Claims

1. A recording medium comprising a substrate having a glossy coating thereon, the glossy coating comprising alumina particles and a binder, wherein the alumina particles are aggregates of primary particles.

2. The recording medium of claim 1, wherein the substrate comprises a polymer or cellulose paper.

3. The recording medium of claim 1 or 2, wherein the substrate comprises poly(ethylene terephthalate).

4. The recording medium of any of claims 1-3, wherein the alumina particles are fumed alumina particles.

5. The recording medium of any of claims 1-4, wherein the aggregates have a mean diameter of about 80-300 nm.

6. The recording medium of any of claims 1-5, wherein the aggregates have a surface area of about 20-400 m2/g.

7. The recording medium of any of claims 1-6, wherein the pigment to binder ratio is at least about 2:1 by weight.

8. A coating composition comprising alumina particles and a binder, wherein the alumina particles are aggregates of primary particles and the solids content of the alumina in the composition is at least about 10 wt.%.

9. The coating composition of claim 8, wherein the alumina particles are fumed alumina particles.

10. The coating composition of claim 8 or 9, wherein the aggregates have a mean diameter of about 80-300 nm.

11. The coating composition of any of claims 8-10, wherein the aggregates have a surface area of about 20-400 m2/g.

12. The coating composition of any of claims 8-11, wherein the pigment to binder ratio is at least about 2:1 by weight.

13. A method of preparing a coating composition, the method comprising:
providing a colloidally stable dispersion comprising water and alumina particles, wherein the alumina particles are aggregates of primary particles and the solids content of the alumina particles in the dispersion is greater than about 20 wt.%;
adding a binder to and, optionally, diluting the colloidally stable dispersion, until a desired pigment to binder ratio and overall solids content are obtained; and optionally adjusting the pH with a suitable acid or base.

14. The method of claim 13, wherein the alumina particles are fumed alumina particles.

15. The method of claim 13 or 14, wherein the aggregates have a mean diameter of about 80-300 nm.

16. The method of any of claims 13-15, wherein the aggregates have a surface area of about 20-400 m2/g.

17. The method of any of claims 13-16, wherein the pigment to binder ratio is at least about 2:1 by weight.

18. The method of any of claims 13-17, wherein the solids content of the alumina particles in the colloidally stable dispersion is at least about 30 wt.%.

19. The method of any of claims 13-18, wherein the zeta potential of the alumina particles in the colloidally stable dispersion is at least about +20 mV.

20. The method of any of claims 13-19, wherein the pH of the colloidally stable dispersion is about 3-5.

21. The method of any of claims 13-20, wherein the specific gravity of the colloidally stable dispersion is about 1-2 kg/1.

22. The method of any of claims 13-21, wherein the apparent viscosity of the colloidally stable dispersion is less than about 20 cp as measured in a Hercules® High-Shear Viscometer at 4400 RPM, FF Bob measuring geometry.

23. The method of any of claims 13-22, wherein the viscosity of the colloidally stable dispersion is less than about 100 cp as measured in a Brookfield Model RV
viscometer, spindle #1, after about 30 seconds at 60 RPM.

24. A coating composition prepared by the method of any of claims 13-23.

25. A method of preparing a recording medium, the method comprising:
providing a substrate;
coating the substrate with the coating composition of any of claims 8-12 to produce a substrate coated with a coating;
optionally calendering the coated substrate; and drying the coated substrate.

26. A method of preparing a recording medium, the method comprising:
providing a substrate;
coating the substrate with the coating composition of claim 24, to produce a substrate coated with a coating;
optionally calendering the coated substrate; and drying the coated substrate.

27. A recording medium prepared by the method of claim 25 or 26.