Patent US4240926A successfully refreshed from Google Patents.
US4240926A
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US
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Sterilization indicator
Assignee: PY MAH Corp
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Filing: 1979-02-26
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Granted: 1980-12-23
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Expires: 1999-02-26
Abstract
Abstract A novel composition is disclosed which is useful as a sterilization indicator that can distinguish clearly between the types of sterilization employed, e.g., that indicates whether sterilization was accomplished by steam or dry heat. The novel composition comprises (1) thiobarbituric acid and (2) at least one suitable reacting moiety being capable of reacting with said acid under temperature and humidity conditions of steam and dry heat sterilization to form a colored product. Suitable reacting moieties disclosed are (a) parabanic acid and (b) dimethyl oxalate and urea.
Inventors
- 👤 Gerald W. McNeely
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 22:18
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/226
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
28 words
A composition capable of recording steam and dry heat sterilizations and capable of differentiating therebetween, comprising: (1) thiobarbituric acid and (2) parabanic acid, to form a colored product.
Claim 2
Dependent Claim
28 words
A composition capable of recording steam and dry heat sterilizations and capable of differentiating therebetween, comprising: (1) thiobarbituric acid and (2) parabanic acid, to form a colored product.
Claim 3
Dependent Claim
33 words
A composition capable of recording steam and dry heat sterilizations and capable of differentiating therebetween, comprising: (1) thiobarbituric acid and (2) a mixture of dimethyl oxalate and urea, to form a colored product.
Claim 4
Dependent Claim
33 words
A composition capable of recording steam and dry heat sterilizations and capable of differentiating therebetween, comprising: (1) thiobarbituric acid and (2) a mixture of dimethyl oxalate and urea, to form a colored product.
Claim 5
Dependent Claim
46 words
An ink capable of changing color in response to temperature and humidity conditions of steam and dry heat sterilizations to record said sterilizations, comprising: (a) the compositions of claims 1 or 2; (b) at least one water insoluble polymeric binder; and (c) a volatile organic solvent.
Claim 6
Dependent Claim
18 words
An ink as in claim 3, wherein said at least one water insoluble polymeric binder is RESINOX RJ-101™.
Claim 7
Dependent Claim
24 words
An ink as in claim 3, wherein said volatile organic solvent is selected from the group consisting of tetrahydrofuran, acetone, and low boiling alcohols.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-12-23 | 1984-06-23 | 1984-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-12-23 | 1988-06-23 | 1988-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-12-23 | 1992-06-23 | 1992-12-23 | $7700.00 | Window Closed / Lapsed |