Patent US4543272A successfully refreshed from Google Patents.
US4543272A
Expired / Lapsed
US
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Insulation process by impregnation of electric leads
Assignee: Alstom SA
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Filing: 1984-07-27
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Granted: 1985-09-24
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Expires: 2004-07-27
Abstract
Abstract Insulation process by impregnation of electric leads using isocyanate and oxazolidone cycle resins in which a glass cloth and porous mica paper tape is wound around the leads, the tape is impregnated with a quaternary ammonium salt, catalyzing condensation of isocyanate and epoxy derivatives in isocyanurate and oxazolidone cycles and with a varnish comprising a liquid epoxy resin and an isocyanate derivative, then the impregnated tape undergoes a heat treatment for polymerization of the varnish. As quaternary ammonium salt, is used a benzyltrialkylammonium halide with alkyl chain containing at most 3 carbon atoms, the tape is first impregnated with benzyltrialkylammonium halide and liquid epoxy resin, it is dried at a temperature equal to 135° C. at maximum and then it is impregnated with isocyanate derivative based varnish before undergoing the polymerizing heat treatment.
Inventors
- 👤 Alain Anton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 17:18
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; C; C08; C08G; C08G18/00; C08G18/003; C08G18/06; C08G18/08; C08G18/16; C08G18/18; C08G18/1875; H01B3/008; H01B3/02; H01B3/04; H01B3/08; H01B3/082; H01B3/303; H01B3/40; C08G2115/00; C08G2115/02; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
135 words
Insulation process by impregnation of electric leads using isocyanate and oxazolidone cycle resins in which a glass cloth and porous mica paper tape is wound around the leads, the tape is impregnated with a quaternary ammonium salt, catalyzing condensation of isocyanate and epoxy derivatives in isocyanurate and oxazolidone cycles and with a varnish comprising a liquid epoxy resin and an isocyanate derivative, then the impregnated tape undergoes a heat treatment for polymerization of the varnish, characterized by use, as quaternary ammonium salt, of a benzyltrialkylammonium halide with alkyl chain containing at most 3 carbon atoms, the tape is first impregnated with benzyltrialkylammonium halide and liquid epoxy resin, it is dried at a temperature equal to 135° C. at maximum and then it is impregnated with isocyanate derivative based varnish before undergoing the polymerizing heat treatment.
Claim 2
Dependent Claim
135 words
Insulation process by impregnation of electric leads using isocyanate and oxazolidone cycle resins in which a glass cloth and porous mica paper tape is wound around the leads, the tape is impregnated with a quaternary ammonium salt, catalyzing condensation of isocyanate and epoxy derivatives in isocyanurate and oxazolidone cycles and with a varnish comprising a liquid epoxy resin and an isocyanate derivative, then the impregnated tape undergoes a heat treatment for polymerization of the varnish, characterized by use, as quaternary ammonium salt, of a benzyltrialkylammonium halide with alkyl chain containing at most 3 carbon atoms, the tape is first impregnated with benzyltrialkylammonium halide and liquid epoxy resin, it is dried at a temperature equal to 135° C. at maximum and then it is impregnated with isocyanate derivative based varnish before undergoing the polymerizing heat treatment.
Claim 3
Dependent Claim
28 words
Process according to claim 1, characterized by the fact that the benzyltrialkylammonium halide is dissolved in the liquid epoxy resin which is then used to impregnate the tape.
Claim 4
Dependent Claim
21 words
Process according to claim 1, characterized by the fact that the benzyltrialkylammonium halide is the benzyltrimethylammonium chloride or the benzyltriethylammonium chloride.
Claim 5
Dependent Claim
31 words
Process according to claim 1, characterized by the fact that the proportion of benzyltrialkylammonium halide is of 0.2 to 5% of weight and preferably 0.8 to 1.5% of total varnish weight.
Claim 6
Dependent Claim
46 words
Process according to claim 1, characterized by the fact that the the respective proportion of liquid epoxy resin and isocyanate derivative are such that the epoxy equivalents/isocyanate equivalents ratio in the final impregnation varnish is included between 1/7 and 1/25 and preferably between 1/20 and 1/25.
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) | 1988-09-23 | 1989-03-25 | 1989-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-23 | 1993-03-25 | 1993-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-23 | 1997-03-25 | 1997-09-24 | $7700.00 | Window Closed / Lapsed |