CA1177548A - Bondable magnet wire - Google Patents
Bondable magnet wireInfo
- Publication number
- CA1177548A CA1177548A CA000386179A CA386179A CA1177548A CA 1177548 A CA1177548 A CA 1177548A CA 000386179 A CA000386179 A CA 000386179A CA 386179 A CA386179 A CA 386179A CA 1177548 A CA1177548 A CA 1177548A
- Authority
- CA
- Canada
- Prior art keywords
- bondable
- enamel
- electrical conductor
- polyamide
- wire
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Insulated Conductors (AREA)
- Organic Insulating Materials (AREA)
Abstract
BONDABLE MAGNET MAGNET WIRE
ABSTRACT OF THE DISCLOSURE
A bondable enamel coated, insulated electrical conductor such as magnet wire. The bondable electrical conductor is formed by a base insulation coating on a metallic conductor such as wire, the base coating being a thermosetting, resin enamel, and a bondable overcoat of polyamide-imide enamel applied on said base coating.
The polyamide-imide enamel includes residual solvent so that the polyamide-imide enamel is self-bondable.
ABSTRACT OF THE DISCLOSURE
A bondable enamel coated, insulated electrical conductor such as magnet wire. The bondable electrical conductor is formed by a base insulation coating on a metallic conductor such as wire, the base coating being a thermosetting, resin enamel, and a bondable overcoat of polyamide-imide enamel applied on said base coating.
The polyamide-imide enamel includes residual solvent so that the polyamide-imide enamel is self-bondable.
Description
~ ~7~ 03-~lM-5380 BONDABLE MAGNET WXRE
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to magnet wire having a bondable coating thereon and more particularly to bondable magnet wire finding particular, but not necessarily exclusive utility for the coil windings of dynamo electric machines adapted for use in hermetic atmospheres.
Descriptio~ of the Prior Art Magnet wire including a bondable overcoat has been described in the art. See, for example U.S. Patent.
No. 2,916,403, issued December 8, 1959, to G.C. Calderwood, for BONDING COMPOSITIONS; U.S. Pat. No. 3,456,338, issued July 22, 1969, to D.W. Mohrman, et al., for METHOD FOR
CHANGING THE CONFIGURATION OF AND FOR BONDING ELECTRICAL
COILS OF INDUCTIVE DEVICES; U.S. Pat. No. 3,300,843, issued January 31, 1967, to T. Umewaka, et al., for SELF BONDING MAGNET WIRE AND METHOD; U.S. Pat. No.3,516,858, issued June 23, 1970, to A.F. Fitzhugh, et al., for SELF-BONDING MAGNET WIRE AND PROCESS FOR PREPARING THE SAME;
U.S. Pat. No. 3,676,814, issued July 11, 1972, to F.F. Trunzo, et al., for HIGH TEMPERATURE ADHESIVE OVERCOAT
FOR MAGNET WIRE; and U.S. Pat. No. 4,152,103, issued May 1, 1979 to R.H. Napiersk-, for DEVICE FOR BAKING SELF-BOND COIL
WIRE.
Polyesterimide wire enamels are well-known and widely used in the art of forming magnet wire for high temperature hermetic applications. Compositions and methods for forming polyesterimide wire enamels are well-known, and the application thereof to wire to form magnet wire is conventional and well-known to those of ordinary skill in the art.
7~ 0 3 ~ 5 3 8 0 Synthetic polyester resin wire enamels are also known and widely utilized. One particularly successful polyester magnet wire insulation resin is manufactured by the General Electric Company under the Trademark ALKANEX, and is disclosed in U.S. Pat. No. 2,936,296, issued May 10, 1960, to F.M. Precopio, et al., for POLYESTERS FROM TEREPHTHALIC ACID, ETHYLENE GLYCOL, AND
A HIGHER POLYFUNCTIONAL ALCOHOL.
Polyamide-imide wire enamels are known and widely used in the art of producing magnet wire. See, ~or example, U.S. Pat.No.3,428,486, issued February 18, 1969, to N.J. George, for POLYAMIDE-IMIDE ELECTRICAL INSULATION;
U.S. Pat. No. 3,475,212, issued October 28, 1969, to H.J. Bach, for METAL CONDUCTOR COATED WITH NONLINEAR
COPOLYESTER BASECOAT LAYER AND POLYAMIDE-IMIDE OUTER
LAYER; U.S. Pat. No. 3,528,852, issued September 15, 1970, to E.H. Olson, et al., for DUAL-COATED ELECTRICAL
CONDUCTOR; and U.S. Pat. No. 3,695,929, issued October 3, 1972, to F.A. Sattler, for CONUDCTORS INSULATED WIT~I A
POLYMERIC AMIDE-IMIDE-ESTER AND AN AROMATIC POLYIMIDE OR
AROMATIC POLYAMIDE-IMIDE OVERCOAT. Polyamide-imide wire enamels are conveniently applied from solutions of the polymer in a solvent, such as n-methyl pyrrolidone (NMP).
For a discussion of the effect of residual solvent on the properties of cured polyamide-imide coatings, see P. Bailey and J.N. Communal, Revue Generale De L'Electricite, Feb. 1978, Vol. 87 #2 at pages 149-159, at pg 152.
The polyamide-imide enamel coating is conventionally applied to the wire substrate from a solution o~ the polyamide-imide in a suitable solvent, such as N-methylpyrrolidone (NMP), in a conventional wire -tower, such as shown for example, in U.S. Pat. No. 3,183,604, ~`~ 03-r[M~53~0 issued May 18, 1965, to J.D. Stauffer, for APPARATUS AND
PROCESS FOR REMOVING SOLVENTS FRO~ COATINGS ON M~TAL; U.S.
Pat. No. 3,1g3,605, issued May 18, 1965 to D.D. Aryue, et al., for APPARATUS FOR COATING ~ETALS; and U.S. Pat. No. 3,351,329, issued November 7, 1967, to D.W. Thomas, for WIRE COATING
OVEN APPARATUS.
OBJECTS AND SUMMARY OF THE INVENTION
The principal object of the present invention is to provide an improved bondable magnet wire having mechanical, electrical and thermal properties suitable for hermetic and high temperature electrical applications.
Another object of the present invention is to provide a bondable magnet wire capble of use in hermetlc motors operating in Freon atmospheres and which maintains the necessary dielectric strength in such atmospheres.
Still another object of the present inven-tion is to provide a bondable magnet wire which retains measurable bond strength at temperatures to which the uni-t formed therefrom may be subjected.
A further object of the present inven-tion is to provide a bondable magnet wire capable of being thermally bonded in short periods of time at a -temperature not exceeding 230C., and effectlve to provide a measurable bond strength between the bondable magnet wire strands at temperatures up to 250C.
Still a further object of the present invention is to provide a bondable magnet wire having flexibility, abrasion resistance, and other characteristics suitable for the automa-tic winding of coils and production of electric motors and like products.
A further object of the invention is to provide a bondable magnet wire of the foregoing character which ~ ~ ~ 03-HM-5380 can be handled, stored and used at normal room conditions.
Other objects and advantages of the present invention will become apparent from -the following description of the prefexred embodiment.
In accordance with the foregoing objects, the present invention comprises a bondable magnet wire formed of a metallic conductor substrate, such as copper or aluminum wire, having a base coating thereon of a material such as a polyesterimide enamel. On top of the base coating there is provided a bondable overcoat of a polyamide-imide enamel. The ratio of thickness of base coat to overcoat is about 2 to 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention comprises a bondable, enamel coated, insulated, electrical conductor. An electrical conductor substrate such as a wire of copper or aluminum, is provided with a base insulation coating thereon. The base insulation coating is formed of cured, solid, thermosetting resin enamel such as a polyesterimide, polyamideimide, polyester, polyimide, polyesteramideimide or -the like. Overcoating the base insulation is a bondable overcoat of solid, undercured polyamide-imide resin, applied from a solution of the polyamide-imide resin in N-methyl pyrrolidone, and undercured to leave residual NMP in the coating. The bondable magnet wire thus formed is comprised of a bondable polyamide-imide overcoat on a polyesterimide or polyester enamel wire, and is suitable for automatic windlng into coils for the production of electric motors and the like.
The magnet wire finds particular, but not necessarily exc'usive utility for use in hermetic atmospheres, and particularly in applications in which the motors are subjected to refrigeran-ts or are adapted for sub-_- 03-HM~5380 mersion in water. The bondable wire exhibits not only the necessary high temperature electrical propertie~, but also the scrape resistance and windability charac-teristics necessary for use in automatic coil winding equipment.
Magnet wire embodying the present invention is readily prepared in conventional wire enamel towers.
Illus~ratively, copper and aluminum wire was provided with a two-thirds of normal film build of polyesterimide enamel at the extremes of cure within the operating range, namely light bake and dark bake. The wires were prepared free of any spooling oil. The wires were then provided with an over-coat of polyamide-imide resin enamel of a thickenss one~
half of the base coat, or a total of one-third of the normal overall coating. The overcoat was partially or undercured in the wire tower to leave residual NMP
solvent in the coating.
Coatings of polyamide-imide enamel are applied to the base coated wire from solutions of the polymer in an appropriate solvent such as N-methyl pyrrolidone (NMP). Small residual amounts of NMP, deliberately left in the polyamide-imide film upon application, cause the polyamide film to be self-bondable and bond to itself under conditions of pressure and temperature achievable within the limits of the current manufacturing process for hermetic motors. Although the NMP solvent is removed from the polyamide-imide film during the bonding operation, it has been found to function as a plasticizer for the polyamide-imide coating to the extent that the wires become bonded to themselves and then display measurable bond strength at 250oc., a temperature adequate for the purposes of producing hermetic mo-tors.
Polyamide-imide magnet wire enamels are commercially ~~ 03-IIM--5380 available, such as AI-600 enamel from the Insulatiny Materials Product Section of General Electric Compan~7, or AI-981 enamel from the P.D. George Co. These illustrative enamels were coated over a polyesterimide film insulation on copper wire in such a fashion that the polyamide-imide was somewhat undercured and contained residual NMP.
Bond strength tests on these self-bondable wires are shown in Table I.
Table I
Pol amideimide Overcoats on Pol esterimide Wire Y ~ . . Y
Overcoat Material WlneTg~8rd Build Bond Strength . _ ~
(ft/min) (mils) @ 250C. (lbs) GENERAL ELECTRI C
AI--600 55 l .7 " 60 1 .6 " 65 1 .8 P.D. GEORGE
AI--981 55 1 .7 " 60 1 .9 ~ 65 1 1.0 The bond strength data given in Table I were determined according to ASTM test D2519, on 3 x l/4" coils made from esterimide/amideimide coated .0427" copper wire. Bonding was achieved by raising the temperature of the wire to 230C. in 5 seconds by resistance heating and maintaining a 230C. temperature for an additional 10 seconds.
The weight loss of 3 foot length wire samples of the above coated wire was determined for conditions similar to those of the bonding operations, and the 30 results are presented in Table II.
S~ 03-~M-5380 Table II
Weight Loss as a Function o~
Residual Solvent per 3 ft of Wire Overcoat Material Wire S~peed Weiqht Loss (mg) (ft/min) 1 min. @ 230C 1 min.@ 2300C.+
5 min.@ 250 C.
GENERAL ELECTRIC
AI-600 55 3.5 10.7 " 60 4.4 12.0 " 65 4.7 12.7 Table II shows tha-t by increasing the wire coating speed in the wire tower, large amounts of residual solvent remain in the coating and thus -the coated wire is self-bondable as demonstrated in Table I.
The bondable magnet wire produced as described above retains its desirable bondable characteristics even after storage at room temperature over a period of several months. It appears that polymer coating retain its solvent under normal room temperature conditions, thus providing for a reasonable commercial shelf lie. It has also been observed that the bondable wire does not self-bond during storage of spools of the bondable wire under ambient conditions, and special storage and handling conditions are not required.
The insulated magnet wire with a bondable coa-ting embodying the present invention may alternatively utilize a polyester base coat under the bondable polyamide-imide overcoat. One illustrative polyester base coat is the polyester ALKANEX, disclosed in U.S. Pat. No. 2,936,296 dated May 10, 1960. As with the polyesterimide, a coating of approximately two-thirds the normal coating thickness of the ALICANEX polyester is applied to a wire substrate, followed by an overcoat of the remaining one-,7 ~5~ 0 3~ M-5 3 ~ 0 third of the polyamide-imide bondable coatiny. The insulated magnet wire thus Eormed is bondable in addition to retaining the properties of the conventional polyester coated magnet wire as disclosed in U.S.Pat.
No. 2,936,296.
The magnet wire may alternatively be provided wikh a polyimide undercoat of a polyimide polymer such as described in Canadian application Serial No.377,580 filed May 14, 1981, by Marvin A. Peterson and Pred F.Holub for IMPROVED POLYAMIDE ACID POLYMER COATING COMPOSITION
AND BONDABLE SUBSTRATE. A coating of the partially imidized polyamide acid coating composition is applied to the wire in a conventional wire tower. The coating is fully cured to a polyimide to provide an electrical grade undercoat on the magnet wire. To the undercoated wire there is then applied an overcoat of polyamideimide, each layer of which is undercured, to produce a bondable magnet wire of the character described herein.
While an illustrative embodiment of the present invention has been described, it should be understood that there is no intention to limik the invention to the specific ~orm disclosed. On the contrary, the intention is to cover all modifications, alternative constructions, equivalents and uses falling within khe spirit and scope of the invention as expressed in the appended claims.
BACKGROUND OF THE INVENTION
Field of the Invention The present invention relates to magnet wire having a bondable coating thereon and more particularly to bondable magnet wire finding particular, but not necessarily exclusive utility for the coil windings of dynamo electric machines adapted for use in hermetic atmospheres.
Descriptio~ of the Prior Art Magnet wire including a bondable overcoat has been described in the art. See, for example U.S. Patent.
No. 2,916,403, issued December 8, 1959, to G.C. Calderwood, for BONDING COMPOSITIONS; U.S. Pat. No. 3,456,338, issued July 22, 1969, to D.W. Mohrman, et al., for METHOD FOR
CHANGING THE CONFIGURATION OF AND FOR BONDING ELECTRICAL
COILS OF INDUCTIVE DEVICES; U.S. Pat. No. 3,300,843, issued January 31, 1967, to T. Umewaka, et al., for SELF BONDING MAGNET WIRE AND METHOD; U.S. Pat. No.3,516,858, issued June 23, 1970, to A.F. Fitzhugh, et al., for SELF-BONDING MAGNET WIRE AND PROCESS FOR PREPARING THE SAME;
U.S. Pat. No. 3,676,814, issued July 11, 1972, to F.F. Trunzo, et al., for HIGH TEMPERATURE ADHESIVE OVERCOAT
FOR MAGNET WIRE; and U.S. Pat. No. 4,152,103, issued May 1, 1979 to R.H. Napiersk-, for DEVICE FOR BAKING SELF-BOND COIL
WIRE.
Polyesterimide wire enamels are well-known and widely used in the art of forming magnet wire for high temperature hermetic applications. Compositions and methods for forming polyesterimide wire enamels are well-known, and the application thereof to wire to form magnet wire is conventional and well-known to those of ordinary skill in the art.
7~ 0 3 ~ 5 3 8 0 Synthetic polyester resin wire enamels are also known and widely utilized. One particularly successful polyester magnet wire insulation resin is manufactured by the General Electric Company under the Trademark ALKANEX, and is disclosed in U.S. Pat. No. 2,936,296, issued May 10, 1960, to F.M. Precopio, et al., for POLYESTERS FROM TEREPHTHALIC ACID, ETHYLENE GLYCOL, AND
A HIGHER POLYFUNCTIONAL ALCOHOL.
Polyamide-imide wire enamels are known and widely used in the art of producing magnet wire. See, ~or example, U.S. Pat.No.3,428,486, issued February 18, 1969, to N.J. George, for POLYAMIDE-IMIDE ELECTRICAL INSULATION;
U.S. Pat. No. 3,475,212, issued October 28, 1969, to H.J. Bach, for METAL CONDUCTOR COATED WITH NONLINEAR
COPOLYESTER BASECOAT LAYER AND POLYAMIDE-IMIDE OUTER
LAYER; U.S. Pat. No. 3,528,852, issued September 15, 1970, to E.H. Olson, et al., for DUAL-COATED ELECTRICAL
CONDUCTOR; and U.S. Pat. No. 3,695,929, issued October 3, 1972, to F.A. Sattler, for CONUDCTORS INSULATED WIT~I A
POLYMERIC AMIDE-IMIDE-ESTER AND AN AROMATIC POLYIMIDE OR
AROMATIC POLYAMIDE-IMIDE OVERCOAT. Polyamide-imide wire enamels are conveniently applied from solutions of the polymer in a solvent, such as n-methyl pyrrolidone (NMP).
For a discussion of the effect of residual solvent on the properties of cured polyamide-imide coatings, see P. Bailey and J.N. Communal, Revue Generale De L'Electricite, Feb. 1978, Vol. 87 #2 at pages 149-159, at pg 152.
The polyamide-imide enamel coating is conventionally applied to the wire substrate from a solution o~ the polyamide-imide in a suitable solvent, such as N-methylpyrrolidone (NMP), in a conventional wire -tower, such as shown for example, in U.S. Pat. No. 3,183,604, ~`~ 03-r[M~53~0 issued May 18, 1965, to J.D. Stauffer, for APPARATUS AND
PROCESS FOR REMOVING SOLVENTS FRO~ COATINGS ON M~TAL; U.S.
Pat. No. 3,1g3,605, issued May 18, 1965 to D.D. Aryue, et al., for APPARATUS FOR COATING ~ETALS; and U.S. Pat. No. 3,351,329, issued November 7, 1967, to D.W. Thomas, for WIRE COATING
OVEN APPARATUS.
OBJECTS AND SUMMARY OF THE INVENTION
The principal object of the present invention is to provide an improved bondable magnet wire having mechanical, electrical and thermal properties suitable for hermetic and high temperature electrical applications.
Another object of the present invention is to provide a bondable magnet wire capble of use in hermetlc motors operating in Freon atmospheres and which maintains the necessary dielectric strength in such atmospheres.
Still another object of the present inven-tion is to provide a bondable magnet wire which retains measurable bond strength at temperatures to which the uni-t formed therefrom may be subjected.
A further object of the present inven-tion is to provide a bondable magnet wire capable of being thermally bonded in short periods of time at a -temperature not exceeding 230C., and effectlve to provide a measurable bond strength between the bondable magnet wire strands at temperatures up to 250C.
Still a further object of the present invention is to provide a bondable magnet wire having flexibility, abrasion resistance, and other characteristics suitable for the automa-tic winding of coils and production of electric motors and like products.
A further object of the invention is to provide a bondable magnet wire of the foregoing character which ~ ~ ~ 03-HM-5380 can be handled, stored and used at normal room conditions.
Other objects and advantages of the present invention will become apparent from -the following description of the prefexred embodiment.
In accordance with the foregoing objects, the present invention comprises a bondable magnet wire formed of a metallic conductor substrate, such as copper or aluminum wire, having a base coating thereon of a material such as a polyesterimide enamel. On top of the base coating there is provided a bondable overcoat of a polyamide-imide enamel. The ratio of thickness of base coat to overcoat is about 2 to 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention comprises a bondable, enamel coated, insulated, electrical conductor. An electrical conductor substrate such as a wire of copper or aluminum, is provided with a base insulation coating thereon. The base insulation coating is formed of cured, solid, thermosetting resin enamel such as a polyesterimide, polyamideimide, polyester, polyimide, polyesteramideimide or -the like. Overcoating the base insulation is a bondable overcoat of solid, undercured polyamide-imide resin, applied from a solution of the polyamide-imide resin in N-methyl pyrrolidone, and undercured to leave residual NMP in the coating. The bondable magnet wire thus formed is comprised of a bondable polyamide-imide overcoat on a polyesterimide or polyester enamel wire, and is suitable for automatic windlng into coils for the production of electric motors and the like.
The magnet wire finds particular, but not necessarily exc'usive utility for use in hermetic atmospheres, and particularly in applications in which the motors are subjected to refrigeran-ts or are adapted for sub-_- 03-HM~5380 mersion in water. The bondable wire exhibits not only the necessary high temperature electrical propertie~, but also the scrape resistance and windability charac-teristics necessary for use in automatic coil winding equipment.
Magnet wire embodying the present invention is readily prepared in conventional wire enamel towers.
Illus~ratively, copper and aluminum wire was provided with a two-thirds of normal film build of polyesterimide enamel at the extremes of cure within the operating range, namely light bake and dark bake. The wires were prepared free of any spooling oil. The wires were then provided with an over-coat of polyamide-imide resin enamel of a thickenss one~
half of the base coat, or a total of one-third of the normal overall coating. The overcoat was partially or undercured in the wire tower to leave residual NMP
solvent in the coating.
Coatings of polyamide-imide enamel are applied to the base coated wire from solutions of the polymer in an appropriate solvent such as N-methyl pyrrolidone (NMP). Small residual amounts of NMP, deliberately left in the polyamide-imide film upon application, cause the polyamide film to be self-bondable and bond to itself under conditions of pressure and temperature achievable within the limits of the current manufacturing process for hermetic motors. Although the NMP solvent is removed from the polyamide-imide film during the bonding operation, it has been found to function as a plasticizer for the polyamide-imide coating to the extent that the wires become bonded to themselves and then display measurable bond strength at 250oc., a temperature adequate for the purposes of producing hermetic mo-tors.
Polyamide-imide magnet wire enamels are commercially ~~ 03-IIM--5380 available, such as AI-600 enamel from the Insulatiny Materials Product Section of General Electric Compan~7, or AI-981 enamel from the P.D. George Co. These illustrative enamels were coated over a polyesterimide film insulation on copper wire in such a fashion that the polyamide-imide was somewhat undercured and contained residual NMP.
Bond strength tests on these self-bondable wires are shown in Table I.
Table I
Pol amideimide Overcoats on Pol esterimide Wire Y ~ . . Y
Overcoat Material WlneTg~8rd Build Bond Strength . _ ~
(ft/min) (mils) @ 250C. (lbs) GENERAL ELECTRI C
AI--600 55 l .7 " 60 1 .6 " 65 1 .8 P.D. GEORGE
AI--981 55 1 .7 " 60 1 .9 ~ 65 1 1.0 The bond strength data given in Table I were determined according to ASTM test D2519, on 3 x l/4" coils made from esterimide/amideimide coated .0427" copper wire. Bonding was achieved by raising the temperature of the wire to 230C. in 5 seconds by resistance heating and maintaining a 230C. temperature for an additional 10 seconds.
The weight loss of 3 foot length wire samples of the above coated wire was determined for conditions similar to those of the bonding operations, and the 30 results are presented in Table II.
S~ 03-~M-5380 Table II
Weight Loss as a Function o~
Residual Solvent per 3 ft of Wire Overcoat Material Wire S~peed Weiqht Loss (mg) (ft/min) 1 min. @ 230C 1 min.@ 2300C.+
5 min.@ 250 C.
GENERAL ELECTRIC
AI-600 55 3.5 10.7 " 60 4.4 12.0 " 65 4.7 12.7 Table II shows tha-t by increasing the wire coating speed in the wire tower, large amounts of residual solvent remain in the coating and thus -the coated wire is self-bondable as demonstrated in Table I.
The bondable magnet wire produced as described above retains its desirable bondable characteristics even after storage at room temperature over a period of several months. It appears that polymer coating retain its solvent under normal room temperature conditions, thus providing for a reasonable commercial shelf lie. It has also been observed that the bondable wire does not self-bond during storage of spools of the bondable wire under ambient conditions, and special storage and handling conditions are not required.
The insulated magnet wire with a bondable coa-ting embodying the present invention may alternatively utilize a polyester base coat under the bondable polyamide-imide overcoat. One illustrative polyester base coat is the polyester ALKANEX, disclosed in U.S. Pat. No. 2,936,296 dated May 10, 1960. As with the polyesterimide, a coating of approximately two-thirds the normal coating thickness of the ALICANEX polyester is applied to a wire substrate, followed by an overcoat of the remaining one-,7 ~5~ 0 3~ M-5 3 ~ 0 third of the polyamide-imide bondable coatiny. The insulated magnet wire thus Eormed is bondable in addition to retaining the properties of the conventional polyester coated magnet wire as disclosed in U.S.Pat.
No. 2,936,296.
The magnet wire may alternatively be provided wikh a polyimide undercoat of a polyimide polymer such as described in Canadian application Serial No.377,580 filed May 14, 1981, by Marvin A. Peterson and Pred F.Holub for IMPROVED POLYAMIDE ACID POLYMER COATING COMPOSITION
AND BONDABLE SUBSTRATE. A coating of the partially imidized polyamide acid coating composition is applied to the wire in a conventional wire tower. The coating is fully cured to a polyimide to provide an electrical grade undercoat on the magnet wire. To the undercoated wire there is then applied an overcoat of polyamideimide, each layer of which is undercured, to produce a bondable magnet wire of the character described herein.
While an illustrative embodiment of the present invention has been described, it should be understood that there is no intention to limik the invention to the specific ~orm disclosed. On the contrary, the intention is to cover all modifications, alternative constructions, equivalents and uses falling within khe spirit and scope of the invention as expressed in the appended claims.
Claims (9)
1. A bondable, non-tacky, enamel coated, insulated, electrical conductor comprising an electrical conductor, a base insulation coating on said conductor of cured, solid, thermosetting, resin enamel, and an overcoat of polyamide-imide enamel on said base coating, characterized in that said polyamide-imide enamel includes residual solvent in an amount such that said polyamide-imide enamel is self-bondable upon heating to a temperature above the ambient temperatures at which said conductor is stored and worked.
2. A bondable electrical conductor as defined in claim 1, wherein said base enamel and said bondable enamel are in a thickness ratio of about 2 to 1 respectively.
3. A bondable electrical conductor as defined in claim 1, wherein said solvent is N-methyl pyrrolidone.
4. A bondable electrical conductor as defined in claim 1, wherein said base enamel is selected from the group consisting of polyesterimide, polyamideimide, polyester, polyimide and polyesteramideimide wire enamels.
5. A bondable enamel coated, insulated, electrical conductor comprising, in combination, an electrical conductor, a base insulation coating on said conductor of cured poly-esterimide enamel, and a bondable overcoat insulation coating on said base coating of polyamide-imide enamel containing residual solvent in an amount sufficient to provide bonding upon heating said overcoat to a temperature of between about 220°C. and about 230°C., but insufficient to cause tack or bonding at ambient temperatures.
6. A bondable electrical conductor as defined in claim 5 wherein said base coating and said overcoating are in a thickness ratio of about 2 to 1 respectively.
7. A bondable electrical conductor as defined in claim 5 wherein said solid thermoplastic, resin enamel is bondable in the range of about 220°C to 230°C.
8. A bondable electrical conductor as defined in claim 5 wherein said base coating and said overcoat retain bonded strength up to at least about 250°C.
9. A bondable electrical conductor as defined in claim 5 wherein said conductor is bondable by resistance raising the temperature of the electrical conductor to a temperature of between 220°C. and 230°C. in a period of approximately five seconds, and maintaining the temperature for approximately an additional 10 seconds.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000386179A CA1177548A (en) | 1981-09-18 | 1981-09-18 | Bondable magnet wire |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000386179A CA1177548A (en) | 1981-09-18 | 1981-09-18 | Bondable magnet wire |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1177548A true CA1177548A (en) | 1984-11-06 |
Family
ID=4120988
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000386179A Expired CA1177548A (en) | 1981-09-18 | 1981-09-18 | Bondable magnet wire |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1177548A (en) |
-
1981
- 1981-09-18 CA CA000386179A patent/CA1177548A/en not_active Expired
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