US3903352A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coated electrical insulating paper and method of making it
Assignee: Kimberly Clark Corp
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Filing: 1971-04-05
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Granted: 1975-09-02
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Expires: 1991-04-05
Abstract
Abstract Electrical insulating paper bearing a surface coating of a material insoluble in liquid dielectrics and substantially free of alkali metals. The coating material is present to the extent of between 2 and 15 percent of the total weight of the coated paper. The coated paper is thinner than otherwise identical uncoated paper having the same dielectric strength, and the coated paper has a percentage increase in dielectric strength greater than the percentage increase in its weight due to the presence of the coating. The coating material is soluble in water within a first range of temperatures and insoluble in water within a second range of temperatures. Prior to application of the coating material to the paper, the material is washed in water within the second range of temperatures to remove alkali metals, and thereafter the material is dissolved in water within the first temperature range to produce an aqueous solution for application to the paper. The coating material may be methyl cellulose, starch, polyvinyl alcohol, or protein.
Inventors
- 👤 Kurt Suter
- 👤 John H Matthews
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:27
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/48; H01B3/485; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31725; Y10T428/31768; Y10T428/31772; Y10T428/31775; Y10T428/31855; Y10T428/3188; Y10T428/31895; Y10T428/31971; Y10T428/31975; Y10T428/31978; Y10T428/31986
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
111 words
ELECTRICAL INSULATING PAPER BEARING A SURFACE COATING OF A MATERIAL INSOLUBLE IN LIQUID DIELECTRICS, SUCH AS CHLORINATED BIPHENYLS AND MINERAL OIL, BEING SUBSTANTIALLY FREE OF ALKALI METALS, SAID COATING MATERIAL BEING INSOLUBLE IN WATER WITHIN ONE TEMPERATURE RANGE BUT SOLUBLE IN WATER WITHIN A DIFFERENT TEMPERATURE RANGE, AND SAID COATING MATERIAL BEING PRESENT TO THE EXTENT OF BETWEEN 2 AND 15 PERCENT OF THE TOTAL WEIGHT OF THE COATED PAPER, SAID COATED PAPER BEING THINNER THAN OTHERWISE IDENTICAL UNCOATED PAPER HAVING THE SAME DIELECTRIC STRENGTH, AND SAID COATED PAPER HAVING A PERCENTAGE INCREASE IN DIELECTRIC STRENGTH GREATER THAN THE PERCENTAGE INCREASE ON ITS WEIGHT DUE TO THE PRESENCE OF THE COATING.
Claim 2
Dependent Claim
111 words
ELECTRICAL INSULATING PAPER BEARING A SURFACE COATING OF A MATERIAL INSOLUBLE IN LIQUID DIELECTRICS, SUCH AS CHLORINATED BIPHENYLS AND MINERAL OIL, BEING SUBSTANTIALLY FREE OF ALKALI METALS, SAID COATING MATERIAL BEING INSOLUBLE IN WATER WITHIN ONE TEMPERATURE RANGE BUT SOLUBLE IN WATER WITHIN A DIFFERENT TEMPERATURE RANGE, AND SAID COATING MATERIAL BEING PRESENT TO THE EXTENT OF BETWEEN 2 AND 15 PERCENT OF THE TOTAL WEIGHT OF THE COATED PAPER, SAID COATED PAPER BEING THINNER THAN OTHERWISE IDENTICAL UNCOATED PAPER HAVING THE SAME DIELECTRIC STRENGTH, AND SAID COATED PAPER HAVING A PERCENTAGE INCREASE IN DIELECTRIC STRENGTH GREATER THAN THE PERCENTAGE INCREASE ON ITS WEIGHT DUE TO THE PRESENCE OF THE COATING.
Claim 3
Dependent Claim
17 words
Electrical insulating paper as defined in claim 1 wherein only one surface of the paper is coated.
Claim 4
Dependent Claim
16 words
Electrical insulating paper as defined in claim 1 wherein both surfaces of the paper are coated.
Claim 5
Dependent Claim
23 words
Electrical insulating paper as defined in claim 1 wherein said coating material contains no more than 200 parts per million of alkali metals.
Claim 6
Dependent Claim
23 words
Electrical insulating paper as defined in claim 1 wherein said coating material contains no more than 20 parts per million of alkali metals.
Claim 7
Dependent Claim
30 words
Electrical insulating paper as defined in claim 1 wherein said coatang is present to the extent of between 3 and 10 percent of the total weight of the coated paper.
Claim 8
Dependent Claim
15 words
Electrical insulating paper as defined in claim 1 wherein said coating material is methyl cellulose.
Claim 9
Dependent Claim
38 words
Electrical insulating paper as defined in claim 7 wherein a 2 percent aqueous solution of said methyl cellulose has a viscosity at 20*C of about 10 to 25 centipose, and a degree of substitution between 1.64 and 1.92.
Claim 10
Dependent Claim
14 words
Electrical insulating paper as defined in claim 1 wherein said coating material is starch.
Claim 11
Dependent Claim
26 words
Electrical insulating paper as defined in claim 9 wherein a 10 percent aqueous solution of said starch has a viscosity at 20*C. below about 200 centipoises.
Claim 12
Dependent Claim
15 words
Electrical insulating paper as defined in claim 1 wherein said coating material is polyvinyl alcohol.
Claim 13
Dependent Claim
36 words
Electrical insulating paper as defined in claim 11 wherein said polyvinyl alcohol is fully hydrolyzed, and a 4 percent aqueous solution of said polyvinyl alcohol has a viscosity at 20*C between about 25 and 125 centipoise.
Claim 14
Dependent Claim
14 words
Electrical insulating paper as defined in claim 1 wherein said coating material is protein.
Claim 15
Dependent Claim
14 words
Electrical insulating paper as defined in claim 11 wherein said protein is alpha protein.
Claim 16
Dependent Claim
26 words
Electrical insulating paper as defined in claim 1 wherein said coating material is selected from the group consisting of methyl cellulose, starch, polyvinyl alcohol, and protein.
Claim 17
Independent Claim
128 words
A method of making electrical insulating paper, comprising the steps of a. providing a material insoluble in liquid dielectrics, such as chlorinated biphenyls and mineral oil, said material being soluble in water within a first temperature range but insoluble in water within a second temperature range, b. washing the material in water within said second temperature range to remove substantially all the alkali metals from the material, c. dissolving the washed material in water within said first temperature range to produce an aqueous solution, d. coating the surface of an electrical insulating paper web with the aqueous solution so that the coating material is present to the extent of between 2 and 15 percent of the total dry weight of the coated paper and e. drying the paper.
Claim 18
Independent Claim
128 words
A method of making electrical insulating paper, comprising the steps of a. providing a material insoluble in liquid dielectrics, such as chlorinated biphenyls and mineral oil, said material being soluble in water within a first temperature range but insoluble in water within a second temperature range, b. washing the material in water within said second temperature range to remove substantially all the alkali metals from the material, c. dissolving the washed material in water within said first temperature range to produce an aqueous solution, d. coating the surface of an electrical insulating paper web with the aqueous solution so that the coating material is present to the extent of between 2 and 15 percent of the total dry weight of the coated paper and e. drying the paper.
Claim 19
Dependent Claim
17 words
A method as defined in claim 16 including adding cations to the wash water of step (b).
Claim 20
Dependent Claim
34 words
A method as defined in claim 17 wherein the cations are added by adding magnesium sulfate or sulfuric acid in an amount of about 0.01 to 0.1 percent by weight of the wash water.
Claim 21
Dependent Claim
16 words
A method as defined in claim 16 wherein the material is finely divided prior to washing.
Claim 22
Dependent Claim
34 words
A method as defined in claim 16 wherein the washing step (b) is carried on until the alkali metal content of the material has been reduced to no more than 200 parts per million.
Claim 23
Dependent Claim
34 words
A method as defined in claim 16 wherein the washing step (b) is carried on until the alkali metal content of the material has been reduced to no more than 20 parts per million.
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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) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |