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US4334973A
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Process for electrophoretically forming an imide coating on wire
Assignee: Siemens Energy Inc
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Filing: 1980-07-18
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Granted: 1982-06-15
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Expires: 2000-07-18
Abstract
Abstract An imide containing polymeric coating is electrophoretically formed on wire from an emulsion. The emulsion contains a polymer, an organic aprotic solvent for the polymer, an amine, and a polar precipitant in which the polymer is insoluble. The wire is passed through a conductive tube immersed in the solvent while a D.C. current is applied between the tube and the wire. The polymer coating on the wire is then cured.
Inventors
- 👤 Nancy W. Carlson
- 👤 Dean C. Westervelt
- 👤 Luciano C. Scala
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 13:43
CPC Classifications
C; C09; C09D; C09D5/00; C09D5/44; C09D5/4419; C09D5/4461
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
187 words
A method of continuously electrophoretically forming an imide containing polymeric coating on a wire comprising: (1) forming an emulsion which comprises: (a) about 0.5 to about 1% by weight based on total emulsion weight of a polymer selected from the group consisting of polysulfones, polyamic acids, polyamide-amic acids, polyamide-amic acid esters, and mixtures thereof; (b) sufficient amine to form a salt with said polymer or to place a charge on emulsion droplets: (c) an organic aprotic solvent for said polymer; and (d) a polar precipitant which forms an emulsion with said solvent and in which said polymer is insoluble, selected from the group consisting of hydroxyethyl acetate, ethylene glycol monomethyl ether, and mixtures thereof, where the lowest boiling liquid in said emulsion boils at at least 120° C. and the highest boiling liquid in said emulsion boils at least 30° C. higher than said lowest boiling liquid; (2) passing said wire through a conductive tube immersed in said emulsion while applying a D.C. electrical current to said tube and said wire, thereby coating said wire with said polymer; and (3) curing said polymer coating on said wire.
Claim 2
Independent Claim
187 words
A method of continuously electrophoretically forming an imide containing polymeric coating on a wire comprising: (1) forming an emulsion which comprises: (a) about 0.5 to about 1% by weight based on total emulsion weight of a polymer selected from the group consisting of polysulfones, polyamic acids, polyamide-amic acids, polyamide-amic acid esters, and mixtures thereof; (b) sufficient amine to form a salt with said polymer or to place a charge on emulsion droplets: (c) an organic aprotic solvent for said polymer; and (d) a polar precipitant which forms an emulsion with said solvent and in which said polymer is insoluble, selected from the group consisting of hydroxyethyl acetate, ethylene glycol monomethyl ether, and mixtures thereof, where the lowest boiling liquid in said emulsion boils at at least 120° C. and the highest boiling liquid in said emulsion boils at least 30° C. higher than said lowest boiling liquid; (2) passing said wire through a conductive tube immersed in said emulsion while applying a D.C. electrical current to said tube and said wire, thereby coating said wire with said polymer; and (3) curing said polymer coating on said wire.
Claim 3
Dependent Claim
13 words
A method according to claim 1 wherein said polymer is a polyamic acid.
Claim 4
Dependent Claim
25 words
A method according to claim 1 wherein said organic aprotic solvent is selected from the group consisting of dimethylsulfoxide, N-methylpyrrolidone, dimethylacetamide, dimethylformamide, and mixtures thereof.
Claim 5
Dependent Claim
40 words
A method according to claim 1 wherein said emulsion includes a solvent extender selected from the group consisting of xylene, toluene, cresylic acid, and mixtures thereof, said extender constituting up to 10% by weight of said solvent plus said extender.
Claim 6
Dependent Claim
14 words
A method according to claim 1 wherein said emulsion is free of any emulsifier.
Claim 7
Dependent Claim
22 words
A method according to claim 1 wherein the volume ratio of said precipitant to said solvent is about 1.5:1 to about 4:1.
Claim 8
Dependent Claim
13 words
A method according to claim 1 wherein said polymer is cured by heating.
Claim 9
Dependent Claim
18 words
A method according to claim 7 wherein said polymer is cured at about 450° to about 480° C.
Claim 10
Dependent Claim
25 words
A method according to claim 1 wherein said emulsion is formed by dissolving said polymer in said solvent and adding said solution to said precipitant.
Claim 11
Dependent Claim
17 words
A method according to claim 1 wherein said precipitant has a lower boiling point than said solvent.
Claim 12
Dependent Claim
15 words
A method according to claim 1 wherein said precipitant is an ethylene glycol monomethyl ether.
Claim 13
Dependent Claim
12 words
A method according to claim 1 wherein the precipitant is hydroxyethyl acetate.
Claim 14
Dependent Claim
11 words
A method according to claim 1 wherein said wire is rectangular.
Claim 15
Dependent Claim
30 words
A method according to claim 1 wherein said electrical current has a voltage of about 200 to about 600 volts and a current of about 50 to about 300 milliamperes.
Claim 16
Dependent Claim
11 words
A method according to claim 1 wherein said tube is vertical.
Claim 17
Dependent Claim
12 words
A method according to claim 1 wherein said amine is 1-methyl imidazole.
Claim 18
Dependent Claim
40 words
A method according to claim 1 wherein the amount of said amine is about 0.5 to about 3 times stoichiometric when an amic acid is used and about 0.8 to about 1.2 parts by weight when a polysulfone is used.
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) | 1985-06-14 | 1985-12-14 | 1986-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-06-14 | 1989-12-14 | 1990-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-06-14 | 1993-12-14 | 1994-06-15 | $7700.00 | Window Closed / Lapsed |