Patent US3867500A successfully refreshed from Google Patents.
US3867500A
Expired / Lapsed
US
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Polyamide-imide film insulation having improved elongation and fold endurance
Assignee: Westinghouse Electric Corp
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Filing: 1973-06-06
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Granted: 1975-02-18
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Expires: 1993-06-06
Abstract
Abstract A heavy gauge, high temperature polyimide and polyamide-imide insulating film having a high fold endurance is made by: (1) depositing a solvent solution of a soluble polyamide precursor as a wet film on a substrate directly followed by (2) initially heating the wet film-substrate composite at a temperature of between about 80*C and 110*C, to partially remove solvent and water and form a tack free film-substrate composite directly followed by (3) heating the film-substrate composite to a temperature of at least about 130*C to further dry and semi-cure the film directly followed by (4) stripping the low solvent film from the substrate directly followed by (5) heating the stripped film at a temperature between about 200*C and 350*C and simultaneously stretching the film up to about 150 percent of its original length, to provide a solid, cured, stretched film.
Inventors
- 👤 Edward J Traynor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:33
CPC Classifications
C; C08; C08L; C08L79/00; C08L79/04; C08L79/08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/14; C09; C09D; C09D179/00; C09D179/04; C09D179/08
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
13 words
A METHOD OF PRODUCING A RESINOUS INSULATING FILM IN A SINGLE PASS BY:
Claim 2
Independent Claim
13 words
A METHOD OF PRODUCING A RESINOUS INSULATING FILM IN A SINGLE PASS BY:
Claim 3
Dependent Claim
28 words
DEPOSITING A SOLVENT SOLUTION OF A SOLUBLE POLYAMIDE PRECURSOR ONTO A SOLID SUBSTRATE, THE SOLUBLE POLYAMIDE PRECURSOR BEING SELECTED FROM THE GROUP CONSISTING OF PRECURSORS HAVING THE STRUCTURE:
Claim 4
Dependent Claim
28 words
DEPOSITING A SOLVENT SOLUTION OF A SOLUBLE POLYAMIDE PRECURSOR ONTO A SOLID SUBSTRATE, THE SOLUBLE POLYAMIDE PRECURSOR BEING SELECTED FROM THE GROUP CONSISTING OF PRECURSORS HAVING THE STRUCTURE:
Claim 5
Dependent Claim
28 words
DEPOSITING A SOLVENT SOLUTION OF A SOLUBLE POLYAMIDE PRECURSOR ONTO A SOLID SUBSTRATE, THE SOLUBLE POLYAMIDE PRECURSOR BEING SELECTED FROM THE GROUP CONSISTING OF PRECURSORS HAVING THE STRUCTURE:
Claim 6
Dependent Claim
28 words
DEPOSITING A SOLVENT SOLUTION OF A SOLUBLE POLYAMIDE PRECURSOR ONTO A SOLID SUBSTRATE, THE SOLUBLE POLYAMIDE PRECURSOR BEING SELECTED FROM THE GROUP CONSISTING OF PRECURSORS HAVING THE STRUCTURE:
Claim 7
Dependent Claim
48 words
The method of claim 1 wherein the solvent solution is deposited as a single layer, the heating in step (III) is between about 130* and 270*C and the film is stretched in step (V) at between about 250* and 325*C and then finally cured at up to 350*C.
Claim 8
Dependent Claim
53 words
The method of claim 1 wherein the solvent solution is deposited as a single layer, the film is heated in step (II) in an atmosphere having a relative humidity of up to about 60 percent, and the film is stretched in step (V) between about 5 and 125 percent of its original length.
Claim 9
Dependent Claim
53 words
The method of claim 1 wherein the heating in step (II) is up to 1 1/2 hours, so that the film contains about 20 to 35 percent volatiles, the heating in step (III) is between about 5 minutes and 2 hours and the semi-cured film is from about 2 to 10 mils thick.
Claim 10
Dependent Claim
29 words
The method of claim 2 wherein the solvent comprises a solvent selected from the group consisting of dimethyl acetamide, dimethyl formamide, N-methyl pyrrolidone, dimethyl sulfoxide, pyridine and mixtures thereof.
Claim 11
Dependent Claim
21 words
The method of claim 2 wherein the soluble polyamide precursor is selected from the group consisting of precursors having the structure:
Claim 12
Dependent Claim
11 words
The method of claim 6 wherein R3 is an oxy radical.
Claim 13
Dependent Claim
11 words
The method of claim 6 wherein R3 is a methylene radical.
Claim 14
Independent Claim
13 words
A METHOD OF PRODUCING A RESINOUS INSULATING FILM IN A SINGLE PASS BY:
Claim 15
Independent Claim
13 words
A METHOD OF PRODUCING A RESINOUS INSULATING FILM IN A SINGLE PASS BY:
Claim 16
Dependent Claim
53 words
The method of claim 9 wherein the solvent comprises a solvent selected from the group consisting of dimethyl acetamide, dimethyl formamide, N-methyl pyrrolidone, dimethyl sulfoxide, pyridine and mixtures thereof, the solvent solution is heated in a non-circulating air oven and the substrate is selected from the group consisting of glass and metal foil.
Claim 17
Dependent Claim
21 words
The method of claim 9 wherein the soluble polyamide precursor is selected from the group consisting of precursors having the structure:
Claim 18
Dependent Claim
11 words
The method of claim 11 wherein R3 is an oxy radical.
Claim 19
Dependent Claim
11 words
The method of claim 11 wherein R3 is a methylene radical.
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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |