US4374221A
Expired / Lapsed
US
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High solids polyamide-imide magnet wire enamel
Assignee: Essex Technology Inc
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Filing: 1981-11-17
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Granted: 1983-02-15
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Expires: 2001-11-17
Abstract
Abstract A high solids content, low molecular weight polymer, low viscosity polyamide-imide enamel is described. The enamel is a reaction product of polyisocyanate, trimellitic anhydride, and an isocyanate blocking alcohol having a ratio of free isocyanate to total carboxyl and anhydride groups of 0.99:1 to 0.85:1. The method of making the enamel and the method of coating electrical conductors such as magnet wire with such enamel are also disclosed.
Inventors
- 👤 Charles W. McGregor
- 👤 Stephen E. Summers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:45
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/28; C08G18/30; C08G18/34; C08G18/343; C08G18/345; C08G73/00; C08G73/06; C08G73/10; C08G73/14; H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/303; H01B3/306; H01B3/308; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/294
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
51 words
A magnet wire enamel comprising a high solids, low viscosity, low molecular weight polymer solvent solution of the reaction product of a polyisocyanate, an isocyanate blocking alcohol and trimellitic anhydride, the ratio of free isocyanate groups to total anhydride and carboxyl groups in the reaction product being about 0.99:1 to 0.85:1.
Claim 2
Dependent Claim
51 words
A magnet wire enamel comprising a high solids, low viscosity, low molecular weight polymer solvent solution of the reaction product of a polyisocyanate, an isocyanate blocking alcohol and trimellitic anhydride, the ratio of free isocyanate groups to total anhydride and carboxyl groups in the reaction product being about 0.99:1 to 0.85:1.
Claim 3
Dependent Claim
10 words
The enamel of claim 1 wherein the polyisocyanate is 4,4'-diisocyanato-diphenylmethane.
Claim 4
Dependent Claim
13 words
The enamel of claim 1 wherein the isocyanate blocking alcohol is benzyl alcohol.
Claim 5
Dependent Claim
10 words
The enamel of claim 1 wherein the solvent is N-methyl-pyrrolidone.
Claim 6
Dependent Claim
17 words
The enamel of claim 1 having a solids content up to 50% by weight at 200° C.
Claim 7
Dependent Claim
20 words
The enamel of claim 1 having a solids content of about 28% to about 45% by weight at 200° C.
Claim 8
Dependent Claim
15 words
The enamel of claim 1 having a viscosity less than 50,000 cps at 30° C.
Claim 9
Dependent Claim
17 words
The enamel of claim 1 having a viscosity of 2000 cps to 15000 cps at 30° C.
Claim 10
Independent Claim
54 words
A method of coating an electrical conductor comprising applying a high solids low viscosity, low molecular weight solvent solution of the reaction product of a polyisocyanate, and isocyanate blocking alcohol and trimellitic anhydride, the ratio of free isocyanate groups to total anhydride and carboxyl groups in the reaction product being about 0.99:1 to 0.85:1.
Claim 11
Independent Claim
54 words
A method of coating an electrical conductor comprising applying a high solids low viscosity, low molecular weight solvent solution of the reaction product of a polyisocyanate, and isocyanate blocking alcohol and trimellitic anhydride, the ratio of free isocyanate groups to total anhydride and carboxyl groups in the reaction product being about 0.99:1 to 0.85:1.
Claim 12
Dependent Claim
10 words
The method of claim 9 wherein the polyisocyanate is 4,4'-diisocyanato-diphenylmethane.
Claim 13
Dependent Claim
13 words
The method of claim 9 wherein the isocyanate blocking alcohol is benzyl alcohol.
Claim 14
Dependent Claim
10 words
The method of claim 9 wherein the solvent is N-methyl-pyrrolidone.
Claim 15
Dependent Claim
20 words
The method of claim 9 wherein the solution has a solids content up to 50% by weight at 200° C.
Claim 16
Dependent Claim
23 words
The method of claim 9 wherein the solution has a solids content of about 28% to about 45% by weight at 200° C.
Claim 17
Dependent Claim
18 words
The method of claim 9 wherein the solution has a viscosity less than 50,000 cps at 30° C.
Claim 18
Dependent Claim
20 words
The method of claim 9 wherein the solution has a viscosity of 2000 cps to 15,000 cps at 30° C.
Claim 19
Dependent Claim
17 words
The method of claim 9 wherein the conductor is magnet wire having a basecoat of polyester thereon.
Claim 20
Independent Claim
50 words
A method of making a high solids content, low viscosity magnet wire enamel comprising reacting trimellitic anhydride with a polyisocyanate and an isocyanate blocking alcohol to form a reaction product in solution having a ratio of free isocyanate groups to total anhydride and carboxylic groups of about 0.99:1 to 0.85:1.
Claim 21
Independent Claim
50 words
A method of making a high solids content, low viscosity magnet wire enamel comprising reacting trimellitic anhydride with a polyisocyanate and an isocyanate blocking alcohol to form a reaction product in solution having a ratio of free isocyanate groups to total anhydride and carboxylic groups of about 0.99:1 to 0.85:1.
Claim 22
Dependent Claim
97 words
The method of claim 18 wherein the trimellitic anhydride is reacted with the polyisocyanate until a percent carboxyl of 10 is obtained in the reaction product, reacting sufficient isocyanate blocking alcohol with the thus formed reaction product to produce a second reaction product having a ratio of free isocyanate groups to total anhydride and carboxyli groups in the second reaction product of about 0.99:1 to about 0.85:1, further reacting by heating the second reaction product until it attains a Gardner-Holdt mix off Viscosity at 30° C. of Z1 to Z5 at 30% to 32% solids by weight.
Claim 23
Dependent Claim
27 words
The method of claim 18 wherein the polyisocyanate is reacted with an isocyanate blocking alcohol to block about 1% to about 15% of the free isocyanate groups.
Claim 24
Dependent Claim
54 words
The method of claim 18 wherein the trimellitic anhydride is reacted with the polyisocyanate until a Gardner-Holdt mix off Viscosity at 30% to 32% solids by weight at 30° C. of Z1 to Z5 is reached, and reacting thus formed reaction product with sufficient isocyanate blocking alcohol to block the remaining free isocyanate functionality.
Claim 25
Independent Claim
14 words
The method of claims 18, 19, 20 or 21 wherein the polyisocyanate is 4,4'-diisocyanato-diphenylmethane.
Claim 26
Independent Claim
17 words
The method of claims 18, 19, 20 or 21 wherein the isocyanate blocking alcohol is benzyl alcohol.
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) | 1986-02-14 | 1986-08-16 | 1987-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-02-14 | 1990-08-16 | 1991-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-02-14 | 1994-08-16 | 1995-02-15 | $7700.00 | Window Closed / Lapsed |