US4148748A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Nonreversible freeze-thaw indicator
Assignee: Dow Chemical Co
•
Filing: 1977-02-22
•
Granted: 1979-04-10
•
Expires: 1997-02-22
Abstract
Abstract A nonreversible freeze-thaw indicator which will detect whether an article has been subjected to freezing or thawing conditions comprising an encapsulated translucent to opaque colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destablized upon freezing which thereafter provides a telltale visual sign if said dispersion rises through its freeze-thaw temperature. After the colloidal dispersion has once been frozen to trigger its irreversible destabilization and is again thawed, it coagulates to form a non-flowing waxy gel, flocculates and precipitates leaving a clear liquid and a coagulated solids layer or partially flocculates to transform a translucent dispersion to a substantially opaque dispersion.
Inventors
- 👤 Robert G. Hanlon
- 👤 Joe A. Craig
- 👤 Leigh B. Bangs
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:45
CPC Classifications
G; G01; G01K; G01K3/00; G01K3/005; C; C09; C09K; C09K3/00; Y; Y10; Y10S; Y10S252/00; Y10S252/962
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
107 words
A nonreversible freeze indicator adapted to detect whether an article has been subjected to freezing conditions comprising an encapsulated translucent to opaque colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destabilized upon freezing which thereafter coagulates to form a non-flowing waxy gel when raised above its freezing temperature thereby providing a telltale visual sign that said indicator has been subjected to freezing conditions, said organic solid particles having a diameter of about 0.7 microns or less and said dispersion having from about 10 weight percent to about 50 weight percent of said organic solid particles.
Claim 2
Dependent Claim
107 words
A nonreversible freeze indicator adapted to detect whether an article has been subjected to freezing conditions comprising an encapsulated translucent to opaque colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destabilized upon freezing which thereafter coagulates to form a non-flowing waxy gel when raised above its freezing temperature thereby providing a telltale visual sign that said indicator has been subjected to freezing conditions, said organic solid particles having a diameter of about 0.7 microns or less and said dispersion having from about 10 weight percent to about 50 weight percent of said organic solid particles.
Claim 3
Dependent Claim
39 words
The freeze indicator of claim 1 wherein said organic solid particles have a diameter of about 0.5 microns or less and said dispersion has from about 20 weight percent to about 50 weight percent of said organic solid particles.
Claim 4
Dependent Claim
42 words
The freeze indicator of claim 1 wherein said organic solid particles are formed from a polymeric resinous material selected from the group consisting of a styrene polymer, styrene/butadiene copolymer, styrene/acrylic acid copolymer, vinyl toluene/tertiarybutylstyrene copolymer, vinylidene chloride/vinyl chloride copolymer or mixtures thereof.
Claim 5
Dependent Claim
39 words
The freeze indicator of claim 3 wherein said organic solid particles have a diameter of about 0.5 micron or less and said dispersion has from about 20 weight percent to about 50 weight percent of said organic solid particles.
Claim 6
Dependent Claim
116 words
A nonreversible freeze-thaw indicator adapted to detect whether an article has been subjected to freezing or thawing conditions comprising an encapsulated translucent to opaque colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destabilized upon freezing which thereafter flocculates and precipitates leaving a clear liquid and a coagulated solids layer when raised above its freezing temperature thereby providing a telltale visual sign that said indicator has been subjected to freezing or thawing conditions, said organic solid particles having a diameter of about 0.3 microns or less and said dispersion having from about 0.1 weight percent to about 10 weight percent of said organic solid particles.
Claim 7
Dependent Claim
116 words
A nonreversible freeze-thaw indicator adapted to detect whether an article has been subjected to freezing or thawing conditions comprising an encapsulated translucent to opaque colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destabilized upon freezing which thereafter flocculates and precipitates leaving a clear liquid and a coagulated solids layer when raised above its freezing temperature thereby providing a telltale visual sign that said indicator has been subjected to freezing or thawing conditions, said organic solid particles having a diameter of about 0.3 microns or less and said dispersion having from about 0.1 weight percent to about 10 weight percent of said organic solid particles.
Claim 8
Dependent Claim
35 words
The freeze-thaw indicator of claim 5 wherein said organic solid particles have a diameter of about 0.2 microns or less and said dispersion has about 5 weight percent or less of said organic solid particles.
Claim 9
Dependent Claim
42 words
The freeze-thaw indicator of claim 5 wherein said organic solid particles are formed from a polymeric resinous material selected from the group consisting of a styrene polymer, styrene/butadiene copolymer, styrene/acrylic acid copolymer, vinyl toluene/tertiarybutylstyrene copolymer, vinylidene chloride/vinyl chloride copolymer or mixtures thereof.
Claim 10
Dependent Claim
38 words
The freeze-thaw indicator of claim 7 wherein said organic solid particles have a diameter of about 0.2 microns or less and said dispersion has about 1 weight percent to about 5 weight percent of said organic solid particles.
Claim 11
Dependent Claim
106 words
A nonreversible freeze indicator adapted to detect whether an article has been subjected to freezing conditions comprising an encapsulated translucent colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destabilized upon freezing which thereafter partially flocculates to form a substantially opaque dispersion when raised above its freezing temperature thereby providing a telltale visual sign that said indicator has been subjected to freezing conditions, said organic solid particles having a diameter of about 0.1 microns or less and said dispersion having from about 0.1 weight percent to about 10 weight percent of said organic solid particles.
Claim 12
Dependent Claim
106 words
A nonreversible freeze indicator adapted to detect whether an article has been subjected to freezing conditions comprising an encapsulated translucent colloidal dispersion of organic solid particles suspended in a liquid medium, said colloidal dispersion having the property of becoming nonreversibly destabilized upon freezing which thereafter partially flocculates to form a substantially opaque dispersion when raised above its freezing temperature thereby providing a telltale visual sign that said indicator has been subjected to freezing conditions, said organic solid particles having a diameter of about 0.1 microns or less and said dispersion having from about 0.1 weight percent to about 10 weight percent of said organic solid particles.
Claim 13
Dependent Claim
39 words
The freeze indicator of claim 9 wherein said organic solid particles have a diameter of about 0.05 microns or less and said dispersion has from about 0.5 weight percent to about 2 weight percent of said organic solid particles.
Claim 14
Dependent Claim
42 words
The freeze indicator of claim 9 wherein said organic solid particles are formed from a polymeric resinous material selected from the group consisting of a styrene polymer, styrene/butadiene copolymer, styrene/acrylic acid copolymer, vinyl toluene/tertiarybutylstyrene copolymer, vinylidene chloride/vinyl chloride copolymer or mixtures thereof.
Claim 15
Dependent Claim
39 words
The freeze indicator of claim 11 wherein said organic solid particles have a diameter of about 0.05 microns or less and said dispersion has from about 0.5 weight percent to about 2 weight percent of said organic solid particles.
References Cited (Backward Citations)
US3122921A
Cited
US3414415A
Cited
US3577352A
Cited
US3521489A
Cited
US3980581A
Cited
US3981683A
Cited
US3981683B1
Cited
US4028944A
Cited
US4064828A
Cited
US4022149A
Cited
US4051804A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-09 | 1982-10-09 | 1983-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-09 | 1986-10-09 | 1987-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-09 | 1990-10-09 | 1991-04-10 | $7700.00 | Window Closed / Lapsed |