Coating processes – Heat decomposition of applied coating or base material
Reexamination Certificate
1999-04-01
2002-07-02
Jones, Deborah (Department: 1775)
Coating processes
Heat decomposition of applied coating or base material
C427S255500, C427S255700, C427S374100, C427S424000, C427S427000, C065S060500, C065S060510, C065S060520, C204S192120, C204S192150, C204S192260, C204S192270
Reexamination Certificate
active
06413581
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of depositing a photocatalytically-activated self-cleaning coating on a substrate (e.g. glass sheet or a continuous glass float ribbon), to a method of preventing sodium ion poisoning of the photocatalytically-activated self cleaning coating deposited over a sodium ion containing substrate and to articles of manufacture prepared according to the methods.
2. Description of the Related Art
For many substrates (e.g. glass substrates), it is desirable that the surface of the substrate remain “clean,” that is to say free of surface contaminants, e.g. common organic and inorganic surface contaminants. Traditionally, this has meant that such surfaces must be cleaned frequently. This cleaning operation is typically performed manually or by mechanical devices. Either approach is quite labor, time and/or cost intensive. A need exists for substrates having surfaces that are self-cleaning or at least easier to clean, which would eliminate or reduce the need for such manual or mechanical cleaning.
Titanium dioxide (TiO
2
) coatings are known to provide a photocatalytically-activated self-cleaning (hereinafter “PASC”) surface on a substrate. Publications directed to the formation of a PASC titanium dioxide coating on a glass substrate include U.S. Pat. No. 5,595,813 and “Photooxidative Self-cleaning Transparent Titanium Dioxide Films on Glass”, Paz et al., J. Mater. Res., Vol. 10, No. 11, pp. 2842-48 (Nov. 1995). Further, a bibliography of patents and articles relating generally to the photocatalytic oxidation of organic compounds is reported in
Bibliography of Work On The Photocatalytic Removal of Hazardous Compounds from Water and Air
, D. Blake, National Renewable Energy Laboratory (May 1994) and in an October 1995 update and an October 1996 update.
A presently available method of applying a PASC coating (e.g. a titanium dioxide PASC coating) to a substrate is the sol-gel method. With the sol-gel method an uncrystallized alcohol-solvent-based colloidal suspension (the sol) is spray, spin, or dip coated onto a substrate at or about room temperature. The substrate is then heated to a temperature within the range of about 100° C. to 800° C. (212° F. to 1472° F.), to either bond the PASC coating to the substrate and/or to cause the crystallization of the PASC coating, in order to form a crystallized PASC coating (the gel) on the substrate.
One limitation of applying a sol-gel PASC coating is that the sol-gel coating method is not economically or practically compatible with certain application conditions or substrates. For example, when it is desired to provide a PASC coating on a float ribbon during manufacture thereof, the ribbon may be too hot to accept the sol depending in part, on the solvent used in the sol solution. For many solvents used in sol-gel process, it is required to cool the hot float ribbon to about room temperature before applying the sol, and to reheat the float ribbon to a temperature sufficient to crystallize the sol into a PASC coating. Such cooling and reheating operations require a substantial investment in equipment, energy and handling costs, and significantly decrease production efficiency.
The PASC activity of PASC coatings may be significantly reduced or destroyed if sodium ions are present in the substrate and migrate from the substrate into the PASC coating. This process is known as sodium poisoning or sodium ion poisoning. For many substrates which contain sodium ions, the rate of migration of sodium ions into coatings increases as the temperature of the substrate increases. Thus another limitation of the sol-gel coating method is that reheating the substrate increases the opportunity for sodium ion migration, and in turn, sodium ion poisoning of a PASC coating.
Another limitation of forming PASC coatings by the sol-gel method is the thickness of the coatings e.g. several microns thick. Such thick PASC coatings may have an adverse affect on the optical and/or aesthetic properties of PASC coated articles.
As can be appreciated from the foregoing, a need exists for an article of manufacture having a PASC coating deposited therein and for a method of depositing a PASC coating that does not suffer from the drawbacks known in the art.
SUMMARY OF THE INVENTION
The present invention is directed to a PASC article of manufacture which includes a substrate having at least one surface and a PASC coating, e.g. titanium dioxide, deposited over the surface of the substrate by a process selected from the group consisting of chemical vapor deposition (hereinafter “CVD”), spray pyrolysis and magnetron sputtered vacuum deposition (hereinafter “MSVD”). The present invention is also directed to a method of making such an article of manufacture.
The present invention is also directed to a PASC article of manufacture which includes a substrate having at least one surface, a sodium ion diffusion barrier (hereafter “SIDB”) layer e.g. tin oxide, titanium dioxide, aluminum oxide layers and mixtures thereof deposited over the surface of the substrate, and a PASC coating e.g. a titanium dioxide coating deposited over the SIDB layer. The PASC coating and the SIDB layer are each deposited by a process selected from the group consisting of CVD, spray pyrolysis and MSVD. The present invention is also directed to a method of making such an article of manufacture.
REFERENCES:
patent: 4112142 (1978-09-01), Schroder et al.
patent: 4329379 (1982-05-01), Terneu et al.
patent: 4351267 (1982-09-01), Kalbskopf et al.
patent: 4751149 (1988-06-01), Viyayakumar et al.
patent: 4878934 (1989-11-01), Thomas et al.
patent: 4971843 (1990-11-01), Michelotti et al.
patent: 4997576 (1991-03-01), Heller et al.
patent: 5041150 (1991-08-01), Grundy et al.
patent: 5194161 (1993-03-01), Heller et al.
patent: 5256616 (1993-10-01), Heller et al.
patent: 5308458 (1994-05-01), Urwin et al.
patent: 5342676 (1994-08-01), Zagdoun
patent: 5348805 (1994-09-01), Zagdoun et al.
patent: 5393593 (1995-02-01), Gulotta et al.
patent: 5505989 (1996-04-01), Jenkinson
patent: 5514454 (1996-05-01), Boire et al.
patent: 5547823 (1996-08-01), Murasawa et al.
patent: 5580364 (1996-12-01), Goodman et al.
patent: 5595813 (1997-01-01), Ogawa et al.
patent: 5616532 (1997-04-01), Heller et al.
patent: 5643436 (1997-07-01), Ogawa et al.
patent: 5736055 (1998-04-01), Cooper
patent: 5753322 (1998-05-01), Yamaguchi et al.
patent: 5755867 (1998-05-01), Chikuni et al.
patent: 5853866 (1998-12-01), Watanabe et al.
patent: 5854169 (1998-12-01), Heller et al.
patent: 5854708 (1998-12-01), Komatsu et al.
patent: 5869187 (1999-02-01), Nakamura et al.
patent: 5873203 (1999-02-01), Thiel
patent: 5939194 (1999-08-01), Hashimoto et al.
patent: 5980983 (1999-11-01), Gordon
patent: 6013372 (2000-01-01), Hayakawa et al.
patent: 6027766 (2000-02-01), Greenberg et al.
patent: 6027797 (2000-02-01), Watanabe et al.
patent: 6037289 (2000-03-01), Chopin et al.
patent: 6054227 (2000-04-01), Greenberg et al.
patent: 6074981 (2000-06-01), Tada et al.
patent: 6090489 (2000-07-01), Hayakawa et al.
patent: 6103353 (2000-08-01), Boire et al.
patent: 6103363 (2000-08-01), Boire et al.
patent: 6165256 (2000-12-01), Hayakawa et al.
patent: 6191062 (2001-02-01), Hayakawa et al.
patent: 6238738 (2001-05-01), McCurdy
patent: 6326079 (2001-12-01), Philippe et al.
patent: 0 581 216 (1994-02-01), None
patent: 0 590 477 (1994-04-01), None
patent: 0 636 702 (1995-02-01), None
patent: 0 684 075 (1995-11-01), None
patent: 0 737 513 (1996-10-01), None
patent: 0 770 579 (1997-05-01), None
patent: 0 780 158 (1997-06-01), None
patent: 0 784 034 (1997-07-01), None
patent: 0 820 967 (1998-01-01), None
patent: 95/10839 (1995-09-01), None
patent: 1 523 991 (1978-09-01), None
patent: 1 524 326 (1978-09-01), None
patent: 2 150 044 (1985-06-01), None
patent: 53-149281 (1978-12-01), None
patent: 61-91041 (1986-05-01), None
patent: 61-91042 (1986-05-01), None
patent: 61-91043 (1986-05-01), None
patent: 91042/1986 (1986-05-01), None
patent: 63-5301 (1988-01-01), None
patent: 63-100042 (1988-05-01), No
Greenberg Charles B.
Harris Caroline S.
Korthuis Vincent
Kutilek Luke A.
Singleton David E.
Jones Deborah
McNeil Jennifer
PPG Industries Ohio Inc.
Stachel Kenneth J.
LandOfFree
Photocatalytically-activated self-cleaning article and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Photocatalytically-activated self-cleaning article and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Photocatalytically-activated self-cleaning article and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2844892