US3909313A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming an electric insulating film having excellent punching property and heat resistance on an electrical steel sheet
Assignee: Nippon Steel Corp
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Filing: 1973-09-21
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Granted: 1975-09-30
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Expires: 1993-09-21
Abstract
Abstract A method for forming on an electrical steel sheet an electric insulating film having excellent punching property and heat resistance comprising coating on the steel sheet a treating solution comprising a composition composed of one or more of chromic anhydride, chromate, bichromate and 1 - 35 parts (as solid) of styrene resin containing not less than 50% stylene and/or vinyl acetate resin emulsion per 10 parts of chromium ion in the composition and heating the coating at a temperature between 150* and 500*C.
Inventors
- 👤 Hirotada Kato
- 👤 Kazuo Nakamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 21:47
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/44; H01B3/448; H01B3/447; H01F; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/147; H01F1/14766; H01F1/14775; H01F1/14783
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
151 words
A METHOD FOR FORMING AN INSULATING FILM HAVING EXCELLENT PUNCHING AND HEAT RESISTANT PROPERTIES ON THE SURFACE OF AN ELECTRICAL STEEL SHEET COMPRISING APPLYING TO AN ELECTRICAL SHEET, A COMPOSITION CONSISTING ESSENTIALLY OF CHROMIC ANHYDRIDE, A CHROMATE OF A BIVALENT METAL OR A BICHROMATE OF A BIVALENT METAL: 1 TO 10 PARTS PER TEN PARTS ON A WEIGHT BASIS OF A REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF SATURATED DICARBOXYLIC ACIDS HAVING 4 OR MORE CARBON ATOMS AND POLYETHYLENE GLCOL, AND 1 TO 35 PARTS OF AN AQUEOUS EMULSION OF A STYRENE RESIN CONTAINING AT LEAST 50% ON A SOLIDS BASIS OF STYRENE OR AN AQUEOUS VINYL ACETATE EMULSION PREPARED USING A NOIONIC OR MIXTURE OF A NONIONIC AND ANIONIC ACTIVATING AGENT, THE VINYL ACETATE EMULSION BEING PREPARED IN THE ABSENCE OF A HIGH MOLECULAR WEIGHT PROTECTIVE COLLOID, AND THEN BAKING THE SHEET AT A TEMPERATURE OF 150* TO 500$C.
Claim 2
Independent Claim
151 words
A METHOD FOR FORMING AN INSULATING FILM HAVING EXCELLENT PUNCHING AND HEAT RESISTANT PROPERTIES ON THE SURFACE OF AN ELECTRICAL STEEL SHEET COMPRISING APPLYING TO AN ELECTRICAL SHEET, A COMPOSITION CONSISTING ESSENTIALLY OF CHROMIC ANHYDRIDE, A CHROMATE OF A BIVALENT METAL OR A BICHROMATE OF A BIVALENT METAL: 1 TO 10 PARTS PER TEN PARTS ON A WEIGHT BASIS OF A REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF SATURATED DICARBOXYLIC ACIDS HAVING 4 OR MORE CARBON ATOMS AND POLYETHYLENE GLCOL, AND 1 TO 35 PARTS OF AN AQUEOUS EMULSION OF A STYRENE RESIN CONTAINING AT LEAST 50% ON A SOLIDS BASIS OF STYRENE OR AN AQUEOUS VINYL ACETATE EMULSION PREPARED USING A NOIONIC OR MIXTURE OF A NONIONIC AND ANIONIC ACTIVATING AGENT, THE VINYL ACETATE EMULSION BEING PREPARED IN THE ABSENCE OF A HIGH MOLECULAR WEIGHT PROTECTIVE COLLOID, AND THEN BAKING THE SHEET AT A TEMPERATURE OF 150* TO 500$C.
Claim 3
Dependent Claim
28 words
A method for forming an electric insulating film as claimed in claim 1, wherein the saturated dicarboxylic acid is adipic acid, sUccinic acid, pimelic acid or glutaric acid.
Claim 4
Dependent Claim
25 words
A method for forming an electric insulating film as claimed in claim 1, wherein the polyethylene glycol has a molecular weight from 200 to 1000.
Claim 5
Dependent Claim
38 words
A method for forming an electric insulating film as claimed in claim 1, wherein the aqueous styrene resin emulsion containing 50% or more of styrene is a styrene emulsion, a styrene-acrylic copolymer emulsion or a styrene-vinyl acetate emulsion.
Claim 6
Dependent Claim
30 words
A method for forming an electric insulating film as claimed in claim 1, wherein the aqueous vinyl acetate emulsion is a vinyl acetate emulsion or a vinyl acetate-acryl copolymer emulsion.
References Cited (Backward Citations)
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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) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |