Stock material or miscellaneous articles – Web or sheet containing structurally defined element or... – Including a second component containing structurally defined...
Reexamination Certificate
2000-09-25
2003-04-22
Le, H. Thi (Department: 1773)
Stock material or miscellaneous articles
Web or sheet containing structurally defined element or...
Including a second component containing structurally defined...
C106S656000, C106S712000, C106S804000, C106S816000, C106S144100, C106S287180, C106S287190, C428S327000, C428S328000, C428S330000, C428S341000, C428S342000
Reexamination Certificate
active
06551701
ABSTRACT:
TECHNICAL FIELD
The present invention is directed to a coating composition for print media. The present invention is further directed to improved print substrates having the coating composition thereon and methods of making the improved print substrates. The improved print substrates substantially enhance the brightness and brilliance of colorants applied to the coating composition, especially compared to colorants applied to conventional coated or uncoated print media.
BACKGROUND OF THE INVENTION
The influence of a substrate on colorant brightness and brilliance can be extremely important. Conventional print substrates typically contain filler materials and/or surface coatings in order to improve the brightness and brilliance of colorants applied thereto. Although many attempts have been made to enhance the brightness and brilliance of colorants, the attempts have resulted in less than acceptable color quality.
There exists a need for methods and compositions, which are capable of enhancing the brightness and brilliance of a wide variety of colorants, especially magenta colorants. There also exists a need for improved substrates, which are providing superior, color quality by enhancing the brightness and brilliance of colorants applied thereto.
SUMMARY OF THE INVENTION
The present invention addresses the needs described above by providing a coating composition and an improved print substrate coated with the composition. The coating composition contains unique microspheres having a refractive index of from about 1.9 to about 2.4. Colorants applied to the improved print substrate exhibit exceptional brightness and brilliance compared to conventional print substrates. In addition, the present invention provides a coating that is elastic and does not cause the substrate to curl when heat is applied.
The present invention is also directed to methods of making the composition and improved substrates described above. Superior color quality, print vibrancy, and colorant brilliance is achieved by combining the aforementioned improved substrates and any colorant composition, particularly ink jet inks.
These and other features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiments.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is directed to a coating composition for print media. The present invention is also directed to improved print substrates comprising a base layer and the above coating composition on at least one surface of the base layer. The improved substrates substantially enhance the brightness and brilliant of colorants applied to the coating composition on the substrate, especially compared to colorants applied to conventional coated or uncoated print media. The present invention is further directed to improved print substrates having the above coating composition thereon and methods of making the improved print substrates.
The coating composition of the present invention comprises microspheres, or beads, having a refractive index of from about 1.9 to about 2.4. The beads are available from The Photographic Institute, Beijing, China, and comprise significant amounts (greater than about 1.0 weight percent) of titanium, barium, calcium and oxygen; minor amounts (less than about 1.0 weight percent) of aluminum, iron, strontium, zinc, and zirconium; and possibly minute amounts of sodium, tellurium, and other elements. An electron microprobe analysis of a bead sample reveals the following bead composition as shown in Table 1 below.
TABLE 1
Aluminum
442
ppm
Boron
<25
ppm
Barium
major
ppm
Beryllium
<25
ppm
Calcium
major
ppm
Cadmium
<25
ppm
Cobalt
<25
ppm
Chromium
<25
ppm
Copper
<25
ppm
Iron
124
ppm
Gallium
<25
ppm
Magnesium
<25
ppm
Manganese
<25
ppm
Molybdenum
<25
ppm
Nickel
<25
ppm
Oxygen
major
ppm
Phosphorus
<25
ppm
Lead
<25
ppm
Tin
<25
ppm
Strontium
2878
ppm
Titanium
major
ppm
Vanadium
<25
ppm
Zinc
3523
ppm
Zirconium
9641
ppm
The commercially available beads are desirably substantially spherical and have particle diameters ranging from about 2 microns to about 45 microns, although having a variety of sizes is not critical to the present invention. As used herein, the phrase “substantially spherical” is intended to encompass beads having a perfectly spherical shape, as well as, beads having an imperfect spherical shape, such as wherein the bead length may be slightly larger or smaller than the bead breath. In one embodiment of the present invention, the commercially available beads are mechanically separated into samples having relatively narrow particle diameter ranges. For example, one sample comprises beads having a particle diameter range of about 27 to about 45 microns. Another sample comprises beads having a particle diameter range of about 2 to about 43 microns. Coating compositions of the present invention may be prepared using commercially available beads or select beads having a desired particle size or particle size range.
Image analysis of two bead samples is given below. All units are in microns.
SAMPLE 1
1 Std
Measurement
Average
Minimum
Maximum
Deviation
Longest
12.68
4.22
43.07
8.18
Dimension
Breath
11.24
2.74
41.52
7.98
Area Equiv.
11.69
3.58
42.18
8.03
Diameter
SAMPLE 2
1 Std
Measurement
Average
Minimum
Maximum
Deviation
Longest
39.80
30.45
44.87
2.82
Dimension
Breath
38.17
27.83
43.35
2.92
Area Equiv.
38.53
28.58
43.75
2.85
Diameter
As shown by the above data, Sample 1 has a broad particle size distribution from about 1 to about 45 microns, while Sample 2 has a much narrower particle size distribution from about 25 to about 45 microns. In both samples, the equivalent circular diameter (area equivalent diameter) is very close to the particle length and breath, indicating that the beads are almost perfectly spherical particles.
The coating composition of the present invention optionally further contains one or more polymeric binders. Suitable binder materials include, but are not limited to, naturally-occurring polymers, synthetically-modified naturally-occurring polymers or synthetic polymers as exemplified in
Water
-
Soluble Polymers,
C. L. McCormick, J. Bock, and D. N. Schulz, in Vol. 17,
Encyclopedia of Polymer Science and Engineering,
John Wiley and Sons, Publishers (1989), pgs. 730-84. Desirably, the binder comprises one or more of the following polymers: polyvinylpyrrolidone (PVP), polyvinylalcohol (PVOH), polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate, polyacrylamide, polymethacrylamide, polyethylene glycol, carboxymethyl cellulose, sodium carboxymethyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, polyacrylic acid and polyacrylic acid salts, polymethacrylic acid and polymethacrylic acid salts, polyvinylsulfonate and polyvinylsulfonate salts, poly-2-acrylamido-2-methylpropanesulfonic acid and poly-2-acrylamido-2-methylpropanesulfonic acid salts, polyacryloxytrimethylammonium chloride, polymethacryloxytrimethylammonium chloride, and polydiallyldimethylammonium chloride. Desirably, the binder comprises sodium carboxymethyl cellulose, polyvinylpyrrolidone (PVP), polyvinylalcohol (PVOH) or a combination thereof. More desirably, the binder comprises polyvinylalcohol (PVOH).
The coating composition may optionally contain one or more cyclodextrins. Suitable cyclodextrins include, but are not limited to, &agr;-cyclodextrin, &bgr;-cyclodextrin, &ggr;-cyclodextrin, &dgr;-cyclodextrin, hydroxypropyl &bgr;-cyclodextrin, hydroxyethyl &bgr;-cyclodextrin, hydroxyethyl &agr; cyclodextrin, carboxymethyl &agr; cyclodextrin, carboxymethyl &bgr; cyclodextrin, carboxymethyl &ggr; cyclodextrin, octyl succinated &agr; cyclodextrin, octyl succinated &bgr; cyclodextrin, octyl succinated &ggr; cyclodextrin and sulfated &bgr; cyclodextrin and sulfated &ggr;-cyclodextrin (Cerestar USA Incorporated, Hammond, Ind.). Desirably, the cyclodextrin comprises &bgr;-cyclodextrin (&bgr;-CD), &ggr;-cyclodextrin (&ggr;-CD), hydroxyethyl &bgr;-cyclodextrin (he-&bgr;-CD), hydroxypropyl &bgr;-cyclodextrin (hp-&bgr;-CD), or
MacDonald John G.
Nohr Ronald S.
Kilpatrick & Stockton LLP
Kimberly--Clark Worldwide, Inc.
Le H. Thi
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