US4576990A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Water-soluble insulating varnish
Assignee: Nitto Denko Corp
•
Filing: 1984-11-15
•
Granted: 1986-03-18
•
Expires: 2004-11-15
Abstract
Abstract An insulating varnish comprising water-soluble polyesters and which can be used as an enamel or protective coating for electric wires is disclosed. The insulating varnish is prepared by reacting an aromatic dicarboxylic acid component and a polyhydric alcohol component to produce a high molecular weight polyester resin, addition reacting a polybasic acid with the resulting polyester resin to obtain a carboxyl group-containing polyester resin and dissolving the resulting polyester resin in water using a basic compound.
Inventors
- 👤 Shiro Mazaki
- 👤 Hiroshi Shibata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:25
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/42; H01B3/421
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
98 words
A water-soluble insulating varnish which is prepared by reacting an aromatic dicarboxylic acid component and a polyhydric alcohol component containing at least 30 mol% of an alcohol having 3 or more hydroxy groups in the amounts such that the ratio of the hydroxyl group to the carboxyl group is from 1.2:1 to 1.8:1 to produce a high molecular weight polyester resin; addition reacting a polybasic acid containing a single anhydride group in the molecule with the polyester resin to obtain a carboxyl group-containing polyester resin; and dissolving the carboxyl group-containing polyester resin in water using a basic compound.
Claim 2
Dependent Claim
98 words
A water-soluble insulating varnish which is prepared by reacting an aromatic dicarboxylic acid component and a polyhydric alcohol component containing at least 30 mol% of an alcohol having 3 or more hydroxy groups in the amounts such that the ratio of the hydroxyl group to the carboxyl group is from 1.2:1 to 1.8:1 to produce a high molecular weight polyester resin; addition reacting a polybasic acid containing a single anhydride group in the molecule with the polyester resin to obtain a carboxyl group-containing polyester resin; and dissolving the carboxyl group-containing polyester resin in water using a basic compound.
Claim 3
Dependent Claim
28 words
The water-soluble insulating varnish of claim 1, wherein the aromatic dicarboxylic acid is selected from the group consisting of terephthalic acid, isophthalic acid, hexahydrophthalic anhydride and mixtures thereof.
Claim 4
Dependent Claim
31 words
The water-soluble insulating varnish of claim 1, wherein the alcohol having 3 or more hydroxyl groups is selected from the group consisting of pentaerythritol, glycerin, trimethylopropane, tris-2-hydroxyethyl isocyanurate and mixtures thereof.
Claim 5
Dependent Claim
52 words
The water-soluble insulating of claim 1, wherein the reaction of the aromatic dicarboxylic acid and the polyhydric alcohol is conducted at 100° to 300° C. for 10 to 15 hours and then at 200° to 240° C. under a reduced pressure of 700 to 740 mmHg for 1 to about 3 hours.
Claim 6
Dependent Claim
40 words
The water-soluble insulating varnish of claim 1, wherein the high molecular weight polyester resin has an acid value of 5 or less, a softening point of 90° to 100° C. and a weight average molecular weight of 3,000 to 20,000.
Claim 7
Dependent Claim
49 words
The water-soluble insulating varnish of claim 1, wherein the polybasic acid containing a single anhydride group in the molecule is selected from the group consisting of phthalic anhydride, 3,6-endomethylene-Δ 4 -tetrahydrophthalic anhydride, methyl-3,6-endomethylene-Δ 4 -tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, itaconic anhydride, butanetetracarboxylic monohydride and mixtures thereof.
Claim 8
Dependent Claim
31 words
The water-soluble insulating varnish of claim 1, wherein the addition reaction of the polyester resin and the polybasic acid is conducted at 100° to 130° C. for 2 to 4 hours.
Claim 9
Dependent Claim
28 words
The water-soluble insulating varnish of claim 1, wherein the polybasic acid is addition reacted to at least 20% of hydroxyl groups in the high molecular weight polyester resin.
Claim 10
Dependent Claim
28 words
The water-soluble insulating varnish of claim 1, wherein the basic compound is selected from the group consisting of ammonia, trialkylamine, N-alkyldiethanolamine, N-N-dialkylethanolamine, monoethanolamine, diethanolamine, triethanolamine and mixtures thereof.
Claim 11
Dependent Claim
24 words
The water-soluble insulating varnish of claim 1, wherein the high molecular weight polyester resin has a weight average molecular weight of 3,000 to 20,000.
Claim 12
Dependent Claim
26 words
The water-soluble insulating varnish of claim 10, wherein the polyhydric alcohol component contains at least 40 mole% of the alcohol having 3 or more hydroxyl groups.
Claim 13
Dependent Claim
16 words
The water-soluble insulating varnish of claim 11, wherein the alcohol has 3 to 5 hydroxyl groups.
Claim 14
Dependent Claim
23 words
The water-soluble insulating varnish of claim 12, wherein the ratio of the hydroxyl group to the carboxyl group is from 1.2:1 to 1.5:1.
Claim 15
Dependent Claim
27 words
The water-soluble insulating varnish of claim 13, wherein the hydroxyl value of the polyester resin is determined by the acetylene method is from about 150 to 300.
References Cited (Backward Citations)
US4008195A
Cited
US4066593A
Cited
US4116941A
Cited
US4104221A
Cited
US4130520A
Cited
US4375528A
Cited
US4439579A
Cited
US4429072A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |