Patent US4158887A successfully refreshed from Google Patents.
Patent US3868221A successfully refreshed from Google Patents.
US3868221A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for degradation testing of stabilized polymers
Assignee: AT&T Inc
•
Filing: 1973-08-31
•
Granted: 1975-02-25
•
Expires: 1993-08-31
Abstract
Abstract Stabilized polymers are tested for resistance to exothermal degradation (e.g., oxidative degradation) at elevated temperatures. An apparatus is used in which several samples are simultaneously inserted into an oven which is maintained at the desired elevated temperature and maintained in the desired atmosphere. For each sample, measurement is made of the period between time of increase of the temperature of that sample, relative to the oven temperature, by a predetermined small temperature interval. It is considered that this temperature rise indicates the onset of accelerated exothermal degradation of that sample and that the time period is a measure of the effectiveness of the stabilizers in the polymer.
Inventors
- 👤 John Benedict Howard
- 👤 Robert Franklin Westover
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 07:55
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/26
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
182 words
APPARTUS FOR THE TESTING OF POLYMERIC MATERIALS CONTAINING AT LEAST ONE ADDITIVE FOR PROTECTION AGAINST EXOTHERMAL DEGRADATION, COMPRISING AN OVEN, WHICH OVEN CONTAINS THERMAL SENSORS EACH OF WHICH CAN PRODUCE AN ELECTRICAL OUTPUT SIGNAL, AND SIGNAL PROCESSING MEANS FOR ACCEPTING AT LEAST ONE OF THE ELECTRICAL OUTPUT SIGNALS AND PRODUCING AT LEAST TIME INTERVAL INFORMATION CHARACTERIZED IN THAT A. THE THERMAL SENSORS INCLUDE AT LEAST ONE REFERENCE SENSOR AND A PLURALITY OF SAMPLE SENSORS, B. THE OVEN INCLUDES SAMPLE INSERTION MEANS FOR INSERTING A PLURALITY OF SAMPLES OF AT LEAST ONE POLYMERIC MATERIAL INTO THE OVEN, THE THERMAL MASS OF WHICH INSERTION MEANS IS AT MOST 10 PERCENT OF THE THERMAL MASS OF THE OVEN, EACH INSERTED SAMPLE BEING BROUGHT INTO THERMAL CONTACT WITH ONE SAMPLE SENSOR, C. THE SIGNAL PROCESSING MEANS INCLUDES MEANS FOR COMPARING THE OUTPUT OF EACH SENSOR WITH THE OUTPUT OF ONE REFERENCE SENSOR AND PRODUCING A DIFFERENCE SIGNAL, THE SIGNAL PROCESSING MEANS INCLUDES MEANS FOR INDICATING THE TIME, RELATIVE TO AN INITIAL TIME, AT WHICH THE DIFFERENCE SIGNAL DERIVED FROM EACH SAMPLE SENSOR, MEETS A PRESET CONDITION.
Claim 2
Dependent Claim
182 words
APPARTUS FOR THE TESTING OF POLYMERIC MATERIALS CONTAINING AT LEAST ONE ADDITIVE FOR PROTECTION AGAINST EXOTHERMAL DEGRADATION, COMPRISING AN OVEN, WHICH OVEN CONTAINS THERMAL SENSORS EACH OF WHICH CAN PRODUCE AN ELECTRICAL OUTPUT SIGNAL, AND SIGNAL PROCESSING MEANS FOR ACCEPTING AT LEAST ONE OF THE ELECTRICAL OUTPUT SIGNALS AND PRODUCING AT LEAST TIME INTERVAL INFORMATION CHARACTERIZED IN THAT A. THE THERMAL SENSORS INCLUDE AT LEAST ONE REFERENCE SENSOR AND A PLURALITY OF SAMPLE SENSORS, B. THE OVEN INCLUDES SAMPLE INSERTION MEANS FOR INSERTING A PLURALITY OF SAMPLES OF AT LEAST ONE POLYMERIC MATERIAL INTO THE OVEN, THE THERMAL MASS OF WHICH INSERTION MEANS IS AT MOST 10 PERCENT OF THE THERMAL MASS OF THE OVEN, EACH INSERTED SAMPLE BEING BROUGHT INTO THERMAL CONTACT WITH ONE SAMPLE SENSOR, C. THE SIGNAL PROCESSING MEANS INCLUDES MEANS FOR COMPARING THE OUTPUT OF EACH SENSOR WITH THE OUTPUT OF ONE REFERENCE SENSOR AND PRODUCING A DIFFERENCE SIGNAL, THE SIGNAL PROCESSING MEANS INCLUDES MEANS FOR INDICATING THE TIME, RELATIVE TO AN INITIAL TIME, AT WHICH THE DIFFERENCE SIGNAL DERIVED FROM EACH SAMPLE SENSOR, MEETS A PRESET CONDITION.
Claim 3
Dependent Claim
32 words
Apparatus of claim 1 in which the oven includes gas insertion means for introducing a gaseous atmosphere of a desired composition into the region of the oven provided for receiving the samples.
Claim 4
Dependent Claim
42 words
Apparatus of claim 2 in which the gas insertion means includes a heat exchanger for raising the temperature of the gas to the operating temperature of the oven before the gas reaches the region of the oven provided for receiving the samples.
Claim 5
Dependent Claim
42 words
Apparatus of claim 1 including means for maintaining the oven at a temperature which is constant to within + or - 5 centigrade degrees during the operating time of the apparatus which includes more than one operation of the sample insertion means.
Claim 6
Dependent Claim
12 words
Apparatus of claim 1 in which the thermal sensors are resistance theremometers.
Claim 7
Dependent Claim
47 words
Apparatus of claim 5 in which the signal processing means possesses sufficient sensitivity to permit the preset condition to correspond to a rise in the temperature of a sample sensor relative to the temperature of the reference sensor by from 0.0l centigrade degree to 1 centigrade degree.
Claim 8
Dependent Claim
46 words
Apparatus of claim 6 in which the signal processing means includes an elapsed time indicator corresponding to each sample sensor, which elapsed time indicator is arranged to start running upon operation of the sample insertion means and to stop running when the preset condition is satisfied.
Claim 9
Dependent Claim
10 words
Apparatus of claim 7 including at least four sample sensors.
Claim 10
Dependent Claim
15 words
Apparatus of claim 8 in which the sample insertion means includes a hydraulically actuated piston.
Claim 11
Independent Claim
135 words
A method for the testing of polymeric materials containing at least one additive for protection against exothermal degradation, comprising: a. maintaining a plurality of polymer samples at an essentially constant measurement temperature in an oxidizing atmosphere for a time period starting at a first time; b. maintaining each portion in thermal contact with one of a plurality of sample thermometer elements; c. comparing each sample thermometer element with a reference theremometer element; d. measuring a time interval for each sample between the first time and a second sample time determined by the rise of the temperature of each sample thermometer element, by a predetermined temperature difference, above the temperature of the reference thermometer element; and e. comparing the time interval with a predetermined time interval whereby the degree of protection against exothermal degradation is indicated.
Claim 12
Independent Claim
135 words
A method for the testing of polymeric materials containing at least one additive for protection against exothermal degradation, comprising: a. maintaining a plurality of polymer samples at an essentially constant measurement temperature in an oxidizing atmosphere for a time period starting at a first time; b. maintaining each portion in thermal contact with one of a plurality of sample thermometer elements; c. comparing each sample thermometer element with a reference theremometer element; d. measuring a time interval for each sample between the first time and a second sample time determined by the rise of the temperature of each sample thermometer element, by a predetermined temperature difference, above the temperature of the reference thermometer element; and e. comparing the time interval with a predetermined time interval whereby the degree of protection against exothermal degradation is indicated.
Claim 13
Dependent Claim
26 words
A method of claim 10 including contacting the samples with a gas stream of linear velocity from 1 millimeter per second to 10 centimeters per second.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |