Patent US3919348A successfully refreshed from Google Patents.
US3919348A
Expired / Lapsed
US
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Epoxy-styrene resin system having improved shelf life
Assignee: Westinghouse Electric Corp
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Filing: 1974-05-23
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Granted: 1975-11-11
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Expires: 1994-05-23
Abstract
Abstract An epoxy-styrene solventless resin impregnating varnish, having an atmospheric catalyzed pot life at room temperature of at least 45 days, is made by mixing: (1) the product of the reaction of (a) 1 part of an epoxy resin mixture comprising solid epoxy resin having an epoxy equivalent weight of between about 390-2500 and liquid epoxy resin having an epoxy equivalent weight of between about 100-385, wherein the weight ratio of solid epoxy: liquid epoxy is between 1:1 to 1:10; with (b) between about 0.01 to 0.06 part of maleic anhydride and (c) between about 0.0001 to 0.005 part of a catalyst selected from the group consisting of piperidine, pyridine, imidazoles, and aliphatic tertiary amines; under such conditions that the reaction between the maleic anhydride and the epoxy resin mixture is substantially complete, and the epoxy diester formed has an acid number of between about 0.5 to 3.0; with (2) a coreactive vinyl monomer, and between about 0.00030 to 0.004 part of an aromatic acidic phenolic compound, selected from the group consisting of dinitrophenols and trinitrophenols; and finally with (3) between about 0.3 to 1.2 part of a polycarboxylic anhydride, which is soluble in the mixture of (1) and (2) at temperatures between about 0* to 35*C, and an amount of free radical catalyst selected from azo compounds and peroxides that is effective to provide a catalytic effect on the impregnating varnish to cure it at temperatures over about 85*C. Upon heating at a temperature over about 85*C, the impregnating composition cures to a thermoset resin.
Inventors
- 👤 Newton C Foster
- 👤 James D B Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:45
CPC Classifications
H; H01; H01B; H01B3/00; H01B3/18; H01B3/30; H01B3/40; C; C08; C08G; C08G59/00; C08G59/18; C08G59/20; C08G59/22; C08G59/226; C08G59/32; C08G59/38; C08G59/40; C08G59/42; C08G59/4207; C08K; C08K5/00; C08K5/16; C08K5/32; C08L; C08L63/00; C08L63/10
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
191 words
A RESINUOUS COMPOSITION COMPRISING THE PRODUCT OF: A. AN EPOXY DIESTER, FORMED FROM THE REACTION OF: 1. 1 PART OF A MIXTURE OF A SOLID EPOXY RESIN HAVING AN EPOXY EQUIVALENT WEIGHT OF BETWEEN ABOUT 390-2500 AND A LIQUID EPOXY RESIN HAVING AN EPOXY EQUIVALENT WEIGHT OF BETWEEN ABOUT 100-385, WHEREIN THE WEIG RATIO OF SOLID EPOXY RESIN: LIQUID EPOXY RESIN IS BETWEEN ABOUT 1:1 TO 1:10, WITH II. BETWEEN ABOUT 0.01 TO 0.06 PART OF MALEIC ANHYDRIDE AND ABOUT 0.0001 TO 0.005 PART OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF PIPERIDINE, PYRIDINE, IMIDAZOLES AND ALIPHATIC TERTIARY AMINES AND MIXTURES THEREOF, WHEREIN SUBSTANTIALLY ALL OF THE MALEIC ANHYDRIDE IS REACTED WITH THE EPOXY RESIN MIXTURE TO FORM AN EPOXY DIESTER HAVING AN ACID NUMBER OF BETWEEN ABOUT 0.5 TO 3.0 TO WHICH ADDED B. BETWEEN ABOUT 0.05 TO 3.0 PARTS OF A VINYL MONOMER CO-REACTIVE WITH THE EPOXY DIESTER AND ABOUT 0.00030 TO 0.004 PART OF AN AROMATIC NITROPHENOL SELECTED FROM THE GROUP CONSISTING OF DINITROPHENOLS AND TRINITROPHENOLS AND MIXTURES THEREOF, TO FORM A SOLVENTLESS, RESINOUS COMPOSITION, HAVING A VISCOSITY OF BETWEEN ABOUT 5 TO 500 CPS AT 25*C.
Claim 2
Dependent Claim
191 words
A RESINUOUS COMPOSITION COMPRISING THE PRODUCT OF: A. AN EPOXY DIESTER, FORMED FROM THE REACTION OF: 1. 1 PART OF A MIXTURE OF A SOLID EPOXY RESIN HAVING AN EPOXY EQUIVALENT WEIGHT OF BETWEEN ABOUT 390-2500 AND A LIQUID EPOXY RESIN HAVING AN EPOXY EQUIVALENT WEIGHT OF BETWEEN ABOUT 100-385, WHEREIN THE WEIG RATIO OF SOLID EPOXY RESIN: LIQUID EPOXY RESIN IS BETWEEN ABOUT 1:1 TO 1:10, WITH II. BETWEEN ABOUT 0.01 TO 0.06 PART OF MALEIC ANHYDRIDE AND ABOUT 0.0001 TO 0.005 PART OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF PIPERIDINE, PYRIDINE, IMIDAZOLES AND ALIPHATIC TERTIARY AMINES AND MIXTURES THEREOF, WHEREIN SUBSTANTIALLY ALL OF THE MALEIC ANHYDRIDE IS REACTED WITH THE EPOXY RESIN MIXTURE TO FORM AN EPOXY DIESTER HAVING AN ACID NUMBER OF BETWEEN ABOUT 0.5 TO 3.0 TO WHICH ADDED B. BETWEEN ABOUT 0.05 TO 3.0 PARTS OF A VINYL MONOMER CO-REACTIVE WITH THE EPOXY DIESTER AND ABOUT 0.00030 TO 0.004 PART OF AN AROMATIC NITROPHENOL SELECTED FROM THE GROUP CONSISTING OF DINITROPHENOLS AND TRINITROPHENOLS AND MIXTURES THEREOF, TO FORM A SOLVENTLESS, RESINOUS COMPOSITION, HAVING A VISCOSITY OF BETWEEN ABOUT 5 TO 500 CPS AT 25*C.
Claim 3
Dependent Claim
101 words
The composition of claim 1 finally mixed with about 0.3 to 1.2 parts a polycarboxylic anhydride which is soluble in the composition of claim 1 at temperature of between about 0*C to 35*C, and an amount of a free radical catalyst selected from the group consisting of azo compounds and peroxies and mixtures thereof that is effective to provide a catalytic curing effect at a temperature over about 85*C; to provide an epoxy-styrene solventless impregnating varnish, having a viscosity of between about 5 to 500 cps at 25*C, and an atmospheric catalyzed pot life at 25*C of at least 45 days.
Claim 4
Dependent Claim
17 words
The solventless impregnating varnish of claim 2, wherein the solid epoxy resin is at least 99.5% pure.
Claim 5
Dependent Claim
31 words
The solventless impregnating varnish of claim 3, wherein the epoxy resins are diglycidyl ethers of bisphenol A, and the solid epoxy resins have an epoxy equivelent weight of between about 390-800.
Claim 6
Dependent Claim
62 words
The solventless impregnating varnish of claim 3, wherein the catalyst is an aliphatic tertiary amine, the vinyl monomer is selected from the group consisting of styrene vinyl toluene, alphamethyl styrene, 2,4-dichlorostyrene, paramethyl styrene, vinyl acetate, methyl methacrylate, ethyl acrylate, methyl vinyl ketone, butyl methacrylate and mixtures thereof, and about 0.01 to 0.001 part of free radical catalyst is used in the reaction.
Claim 7
Dependent Claim
84 words
The solventless impregnating varnish of claim 5, wherein the aromatic nitrophenol is selected from the group consisting of picric acid; 2,4 dinitrophenol; 2,6 dinitrophenol, dinitroresorcinol and trinitroresorcinol and mixtures thereof; and the polycarboxylic anhydride which is mixed with the formed epoxy diester selected from the group consisting of NADIC methyl anhydride, a eutectic mixture of tetrahydrophthalic anhydride and hexahydrophthalic anhydride, dodecenyl succinic anhydride, trimellitic anhydride, methyl tetrahydrophthalic anhydride, chlorendic anhydride, benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, phthalic anhydride and 1-methyl hexahydrophthalic anhydride and mixtures thereof.
Claim 8
Dependent Claim
25 words
The solventless impregnating varnish of claim 5, impregnated into electrical component insulation, and cured at a temperature over about 85*C, to form a thermoset resin.
Claim 9
Dependent Claim
25 words
An insulated electrical member and a cured body of resinous insulation applied to the member, the insulation comprising the cured resinous composition of claim 5.
Claim 10
Dependent Claim
38 words
An insulated electrical transformer comprising a magnetic core, electrical windings disposed about the magnetic core, and having a body of cured resinous insulation applied to the electrical windings, the insulation comprising the cured resinous composition of claim 5.
Claim 11
Dependent Claim
244 words
A resinous composition, useful for impregnating insulated electrical components, consisting essentially of the product of mixing: A. an epoxy diester, formed from an essentially complete esterification reaction of: I. 1 part of a mixture of a solid epoxy resin having an epoxy equivalent weight of between about 390-800 and a liquid epoxy resin having an epoxy equivalent weight of between about 100-385, wherein the weight ratio oF solid epoxy resin: liquid epoxy resin is between about 1:1 to 1:10, with II. between about 0.01 to 0.06 part of maleic anhydride and about 0.0001 to 0.005 part of an aliphatic tertiary amine catalyst, wherein substantially all of the maleic anhydride is reacted with the epoxy resin mixture to form an epoxy diester having an acid number of between about 0.5 to 3.0 to which is added B. between about 0.05 to 3.0 parts of styrene, about 0.00030 to 0.004 part of picric acid as a stabilizer for the diester-styrene mixture, about 0.3 to 1.2 parts of a polycarboxylic anhydride which is soluble in the epoxy diester-styrene-picric acid mixture at temperatures of between about 0*C to 35*C, and about 0.01 to 0.001 part of peroxide catalyst that is effective to provide a catalytic curing effect on the mixture at a temperature over about 85*C; to provide an epoxystyrene solventless impregnating varnish, having a viscosity of between about 5 to 500 cps at 25*C and an atmospheric catalyzed pot life at 25*C of at least 45 days.
Claim 12
Dependent Claim
244 words
A resinous composition, useful for impregnating insulated electrical components, consisting essentially of the product of mixing: A. an epoxy diester, formed from an essentially complete esterification reaction of: I. 1 part of a mixture of a solid epoxy resin having an epoxy equivalent weight of between about 390-800 and a liquid epoxy resin having an epoxy equivalent weight of between about 100-385, wherein the weight ratio oF solid epoxy resin: liquid epoxy resin is between about 1:1 to 1:10, with II. between about 0.01 to 0.06 part of maleic anhydride and about 0.0001 to 0.005 part of an aliphatic tertiary amine catalyst, wherein substantially all of the maleic anhydride is reacted with the epoxy resin mixture to form an epoxy diester having an acid number of between about 0.5 to 3.0 to which is added B. between about 0.05 to 3.0 parts of styrene, about 0.00030 to 0.004 part of picric acid as a stabilizer for the diester-styrene mixture, about 0.3 to 1.2 parts of a polycarboxylic anhydride which is soluble in the epoxy diester-styrene-picric acid mixture at temperatures of between about 0*C to 35*C, and about 0.01 to 0.001 part of peroxide catalyst that is effective to provide a catalytic curing effect on the mixture at a temperature over about 85*C; to provide an epoxystyrene solventless impregnating varnish, having a viscosity of between about 5 to 500 cps at 25*C and an atmospheric catalyzed pot life at 25*C of at least 45 days.
Claim 13
Independent Claim
323 words
A method of making an epoxy-styrene solventless impregnating varnish, comprising the steps of: A. reacting at a temperature of between about 80*C to 100*C; I. 1 part of a mixture of solid epoxy resin having an epoxy equivalent weight of between about 390-2500 and a liquid epoxy resin having an epoxy equivalent weight of between about 100-385, wherein the weight ratio of solid epoxy resin: liquid epoxy resin is between about 1:1 to 1:10, with II. between about 0.01 to 0.06 part of maleic anhydride and about 0.0001 to 0.005 part of a catalyst selected from the group consisting of piperidine, pyridine, imidazoles and aliphatic tertiary amines and mixtures thereof, so that substantially all of the maleic anhydride reacts with the epoxy resin mixture to form an epoxy diester having an acid number between about 0.5 to 3.0, and then B. mixing the epoxy diester at a temperature of between about 50*C to 90*C with about 0.05 to 3.0 parts of a vinyl monomer co-reactive with the epoxy diester and about 0.00030 to 0.004 part of an aromatic nitrophenol selected from the group consisting of dinitrophenols and trinitrophenols and mixtures thereof, to form an epoxy diester-styrene-nitrophenol composition having a viscosity of between about 5 to 500 cps at 25*C; and then C. mixing the epoxy diester-styrene-nitrophenol composition at a temperature of between 0*C to 35*C with about 0.3 to 0.8 part of a polycarboxylic anhydride which is soluble in the epoxy diester-styrene-nitrophenol composition at a temperature of between about 0*C to 35*C, and an amount of a free radical catalyst selected from the group consisting of azo compounds and peroxides and mixtures thereof that is effective to provide a catalytic curing effect for the mixture at a temperature over about 85*C; to provide an epoxy-styrene solventless impregnating varnish, having a viscosity of between about 5 to 500 cps at 25*C and an atmospheric catalyzed pot life at 25*C of at least 45 days.
Claim 14
Independent Claim
323 words
A method of making an epoxy-styrene solventless impregnating varnish, comprising the steps of: A. reacting at a temperature of between about 80*C to 100*C; I. 1 part of a mixture of solid epoxy resin having an epoxy equivalent weight of between about 390-2500 and a liquid epoxy resin having an epoxy equivalent weight of between about 100-385, wherein the weight ratio of solid epoxy resin: liquid epoxy resin is between about 1:1 to 1:10, with II. between about 0.01 to 0.06 part of maleic anhydride and about 0.0001 to 0.005 part of a catalyst selected from the group consisting of piperidine, pyridine, imidazoles and aliphatic tertiary amines and mixtures thereof, so that substantially all of the maleic anhydride reacts with the epoxy resin mixture to form an epoxy diester having an acid number between about 0.5 to 3.0, and then B. mixing the epoxy diester at a temperature of between about 50*C to 90*C with about 0.05 to 3.0 parts of a vinyl monomer co-reactive with the epoxy diester and about 0.00030 to 0.004 part of an aromatic nitrophenol selected from the group consisting of dinitrophenols and trinitrophenols and mixtures thereof, to form an epoxy diester-styrene-nitrophenol composition having a viscosity of between about 5 to 500 cps at 25*C; and then C. mixing the epoxy diester-styrene-nitrophenol composition at a temperature of between 0*C to 35*C with about 0.3 to 0.8 part of a polycarboxylic anhydride which is soluble in the epoxy diester-styrene-nitrophenol composition at a temperature of between about 0*C to 35*C, and an amount of a free radical catalyst selected from the group consisting of azo compounds and peroxides and mixtures thereof that is effective to provide a catalytic curing effect for the mixture at a temperature over about 85*C; to provide an epoxy-styrene solventless impregnating varnish, having a viscosity of between about 5 to 500 cps at 25*C and an atmospheric catalyzed pot life at 25*C of at least 45 days.
Claim 15
Dependent Claim
14 words
The method of claim 11, wherein the solid epoxy is at least 99.5% pure.
Claim 16
Dependent Claim
30 words
The method of claim 12, wherein the epoxy resin is a diglycidyl ether of bisphenol A, and the solid epoxy resins have an epoxy equivalent weight of between about 390-800.
Claim 17
Dependent Claim
75 words
The method of claim 12 wherein the epoxy mixture and maleic anhydride are reacted for about 3 to 6 hours in step (A), the catalyst is an aliphatic tertiary amine, the vinyl monomer is selected from the group consisting of styrene, vinyl toluene, alphamethyl styrene, 2,4-DICHLOROSTYRENE, paramethyl styrene, vinylacetate, methyl methacrylate, ethyl acrylate, methyl vinyl ketone, butyl methacrylate and mixtures thereof, and about 0.01 to 0.001 part of peroxide catalyst is used in step (C).
Claim 18
Dependent Claim
86 words
The method of claim 14 wherein the aromatic nitrophenol is selected from the group consisting of picric acid; 2,4 dinitrophenol; 2,6 dinitrophenol; dinitroresorcinol and trinitroresorcinol and mixtures thereof, and the polycarboxylic anhydride which is mixed with the formed epoxy diester in step (C), is selected from the group consisting of NADIC methyl anhydride, a eutectic mixture of tetrahydrophthalic anhydride and hexahydrophthalic anhydride, dodecenyl succinic anhydride, trimellitic anhydride, methyl tetrahydrophthalic anhydride, chlorendic anhydride, benzophenone tetracarboxylic dianhydride, pyromellitic dianhydride, phthalic anhydride and 1-methyl hexahydrophthalic anhydride and mixtures thereof.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |