Patent US4678640A successfully refreshed from Google Patents.
US4678640A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Indicator for detecting residual ethylene oxide
Assignee: Ekika Carbon Dioxide Co Ltd
•
Filing: 1985-11-18
•
Granted: 1987-07-07
•
Expires: 2005-11-18
Abstract
Abstract An indicator for detecting residual ethylene oxide comprising a substrate impregnated with a solution of 4-(4-nitrobenzyl)pyridine and an envelope of the substrate which is at least partially transparent and has low permeability to gaseous ethylene oxide is provided, the envelope being preferably made of a transparent plastic film. With the indicator, an amount of ethylene oxide remaining in various medical instruments, etc. may be estimated by the naked eye since the color of the indicator changes step by step in the course of the release of residual ethylene oxide.
Inventors
- 👤 Masanori Hamano
- 👤 Siro Takeuchi
- 👤 Ichiro Inoue
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 20:28
CPC Classifications
G; G01; G01N; G01N31/00; G01N31/22; G01N31/223; G01N31/226; Y; Y10; Y10T; Y10T436/00; Y10T436/14; Y10T436/142222
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
151 words
An indicator for estimating concentrations of ethylene oxide remaining in medical instruments or sanitary goods during or after aeration following sterilization of said instruments or goods with ethylene oxide comprising: (a) a substrate formed by impregnating a paper body with a solution consisting of about 0.5-5% by weight of 4-(4- nitrobenzyl)-pyridine in an organic solvent and removing said solvent; and (b) an envelope enclosing said substrate, said envelope comprising a transparent, heat-sealable single layer or composite plastic film having a low permeability to ethylene oxide and a permeability to carbon dioxide of not more than about 200 ml/100 in 2 /mil/24 hours at 25° C. under 1 atmosphere and at 50% relative humidity, said substrate sequentially changing color step-wise following the exposure of the indicator to ethylene oxide gas, with the color change of said substrate during the aeration being controlled by said envelope having a low permeability to ethylene oxide.
Claim 2
Dependent Claim
151 words
An indicator for estimating concentrations of ethylene oxide remaining in medical instruments or sanitary goods during or after aeration following sterilization of said instruments or goods with ethylene oxide comprising: (a) a substrate formed by impregnating a paper body with a solution consisting of about 0.5-5% by weight of 4-(4- nitrobenzyl)-pyridine in an organic solvent and removing said solvent; and (b) an envelope enclosing said substrate, said envelope comprising a transparent, heat-sealable single layer or composite plastic film having a low permeability to ethylene oxide and a permeability to carbon dioxide of not more than about 200 ml/100 in 2 /mil/24 hours at 25° C. under 1 atmosphere and at 50% relative humidity, said substrate sequentially changing color step-wise following the exposure of the indicator to ethylene oxide gas, with the color change of said substrate during the aeration being controlled by said envelope having a low permeability to ethylene oxide.
Claim 3
Dependent Claim
17 words
The indicator of claim 1, in which the plastic film is made of polyvinyl alcohol or nylon.
Claim 4
Dependent Claim
37 words
The indicator of claim 1 wherein the plastic film comprises a composite film comprising an outer layer having low permeability to gaseous ethylene oxide and an inner layer having heat-sealability and high permeability to gaseous ethylene oxide.
Claim 5
Dependent Claim
30 words
The indicator of claim 3 wherein the outer layer is formed from a material selected from the group consisting of polyester, nylon, polyvinyl alcohol, polyvinylidene chloride, polyvinyl fluoride and cellophane.
Claim 6
Dependent Claim
13 words
The indicator of claim 3 wherein the inner layer comprises polyethylene or polypropylene.
Claim 7
Dependent Claim
25 words
The indicator of claim 3 wherein the composite film comprises a polyester film as an outer layer and a polypropylene film as an inner layer.
Claim 8
Dependent Claim
29 words
The indicator of claim 3 wherein the outer layer is formed from a material selected from the group consisting of polyester, nylon, polyvinyl alcohol, polyvinylidene chloride and polyvinyl fluoride.
Claim 9
Dependent Claim
32 words
The indicator of claim 1 wherein the envelope comprises a base plate made of metal foil and a plastic film having low permeability to gaseous ethylene oxide, the substrate being enclosed therebetween.
Claim 10
Dependent Claim
23 words
The indicator of claim 1 wherein the paper body is selected from the group consisting of filter paper, synthetic paper and blotting paper.
Claim 11
Dependent Claim
18 words
The indicator of claim 1 wherein the substrate is in the form of a strip, flake or tablet.
References Cited (Backward Citations)
GB854142A
Cited
US2998306A
Cited
US3627469A
Cited
US3738811A
Cited
GB1506401A
Cited
GB1523277A
Cited
US3992154A
Cited
JPS5321871A
Cited
US4094642A
Cited
JPS53138393A
Cited
US4138216A
Cited
US4138216B1
Cited
US4195058A
Cited
US4495291A
Cited
US4436819A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-07-06 | 1991-01-05 | 1991-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-07-06 | 1995-01-05 | 1995-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-07-06 | 1999-01-05 | 1999-07-07 | $7700.00 | Window Closed / Lapsed |