Freeze indicator
AssigneePyMaH Corporation
InventorsRamon T. Ignacio, Raymond P. Larsson
Life of this patent
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Abstract
A freeze indicator comprising a frangible ampule containing a liquid which expands upon freezing, a dye soluble in the liquid and a nucleating agent, the nucleating agent and the liquid having substantially similar space groupings, the ampule being enclosed within a blister of transparent film, the blister being adhered to a backing, the inner surface of the blister being coating with an absorbent layer comprising a binder wettable by the liquid and a filler, whereby upon rupture of the ampule the liquid containing dye is absorbed by the absorbent layer thereby causing a color change in the absorbent layer visible through the transparent film.
Claims59
In a freeze indicator comprising a frangible ampule containing a liquid which expands upon freezing, a dye soluble in the liquid and a nucleating agent, said nucleating agent and said liquid having substantially similar space groupings, said ampule being enclosed within a blister of transparent film, the blister being adhered to a backing, the improvement which comprises coating the inner surface of the blister with an absorbent layer comprising a binder wettable by said liquid and a filler, whereby upon rupture of the ampule the liquid containing dye is absorbed by the absorbent layer thereby causing a color change in said absorbent layer visible through the transparent film.
A freeze indicator comprising a frangible ampule containing a liquid comprising deuterium oxide, a dye soluble in the liquid, and a nucleating agent, said nucleating agent and said liquid having substantially similar space groupings, said ampule being enclosed within a blister of transparent film, the blister being adhered to a backing, the inner surface of the blister being coated with an absorbent layer comprising a binder wettable by said liquid and a filler, whereby upon rupture of the ampule the liquid containing dye is absorbed by the absorbent layer thereby causing a color change in said absorbent layer visible through the transparent film, wherein:
- (a) the binder is a mixture of at least one water soluble binder and at least on water insoluble binder;
- (b) the filler is titanium dioxide, calcium carbonate hydrated silica or mixtures thereof;
- and
- (c) the dye is methylene blue, Safranin O, bromphenol blue, metacresol purple, bromthymol blue, analine blue, basic fuchsin or malachite green.
Dependencies are inferred from the claim text.