Compositions – Nonreactive analytical – testing – or indicating compositions
Reexamination Certificate
2008-01-01
2008-01-01
Corcoran, Gladys J P (Department: 1744)
Compositions
Nonreactive analytical, testing, or indicating compositions
Reexamination Certificate
active
10839203
ABSTRACT:
The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.
REFERENCES:
patent: 1331257 (1920-02-01), Heap et al.
patent: 2460065 (1949-01-01), Davis
patent: 2756124 (1956-07-01), Patterson et al.
patent: 2777856 (1957-01-01), Stokes
patent: 3646080 (1972-02-01), Pobiner
patent: 4532071 (1985-07-01), Nakamura et al.
patent: 5178664 (1993-01-01), Picard
patent: 5607619 (1997-03-01), Dadgar et al.
patent: 6043096 (2000-03-01), Evtodienko et al.
patent: 6066305 (2000-05-01), Dugger
patent: 6753184 (2004-06-01), Moreton et al.
patent: 2005/0181119 (2005-08-01), Tahon et al.
patent: WO 02/057772 (2002-07-01), None
Forsberg, J. H and Moeller, T.□□Observations on the Rare Earths. LXXIX. The Synhteses and Properties of Ethylenediamine Chelates of the Tripositive Lanthanide Ions□□Inorganic Chemistry, Vl. 8, No. 4, pp. 883-888, Apr. 1969.
Greenwood, N. N. and Earnshaw, A.□□Chemistry of the Elements□□1997, Butterworth Heinemann, Oxford, 2nd Ed.□□pp. 1227-1242.
Tahon, et al., Method of Preparing Storage Phosphors from Dedicated Precursors, U.S. Appl. No. 60/535,971, filed Jan. 12, 2004.
Beitz James V.
Williams Clayton W.
Corcoran Gladys J P
Dobbs Michael J.
Gottlieb Paul A.
Lally Brian J.
U.S. Department of Energy
LandOfFree
Lanthanide-halide based humidity indicators does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lanthanide-halide based humidity indicators, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lanthanide-halide based humidity indicators will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3942980