US3546017A - Electrodeposition of particulate coating material - Google Patents

Electrodeposition of particulate coating material Download PDF

Info

Publication number
US3546017A
US3546017A US681198A US3546017DA US3546017A US 3546017 A US3546017 A US 3546017A US 681198 A US681198 A US 681198A US 3546017D A US3546017D A US 3546017DA US 3546017 A US3546017 A US 3546017A
Authority
US
United States
Prior art keywords
particles
coating
barium titanate
conductor
dielectric
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 - Lifetime
Application number
US681198A
Inventor
Wesley W Pendleton
William W Ulmer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Atlantic Richfield Co
Original Assignee
Anaconda Wire and Cable Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Anaconda Wire and Cable Co filed Critical Anaconda Wire and Cable Co
Application granted granted Critical
Publication of US3546017A publication Critical patent/US3546017A/en
Assigned to ATLANTIC RICHFIELD COMPANY, A PA CORP. reassignment ATLANTIC RICHFIELD COMPANY, A PA CORP. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: ANACONDA COMPANY THE, A DE CORP
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01BCABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B13/00Apparatus or processes specially adapted for manufacturing conductors or cables
    • H01B13/0033Apparatus or processes specially adapted for manufacturing conductors or cables by electrostatic coating
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S524/00Synthetic resins or natural rubbers -- part of the class 520 series
    • Y10S524/901Electrodepositable compositions

Definitions

  • This invention relates to the coating of surfaces and particularly to the continuous coating of elongated conductors by electrostatic deposition.
  • application Ser. No. 588,511, now patent 3,396,699 an improvement is described in apparatus for electrostatically coating a continuous conductor passing through a cloud of particles above a fluid bed, and coating apparatus is commercially available in several varieties that operate on principles of electrostatics.
  • an electrical potential usually in the range of 30,000-l00,0 ⁇ 00 volts, is impressed between the object to be coated and an electrode spaced from the object.
  • the coating particles are introduced between the electrode and the object and may become charged either by contact with the electrode, other charged particles, or the ionized air.
  • Our invention comprises also the powdered mixture, for deposition, of particles of a coating material, and a small weight percentage of a substance, such as barium titanate, with a dielectric constant in excess of 1500.
  • a substance such as barium titanate
  • the barium titanate or other high-dielectric-constant substance is preferably substantially finer than the coating material.
  • the coating material of our mixture comprises an organic resin such as an epoxy.
  • FIG. 1 represents a container of the mixture of our invention with the particle sizes very much enlarged.
  • FIG. 2 shows a scheme of the process of our invention.
  • a mixture indicated generally by the numeral 10, has been prepared for coating the surface of an object such as an electrical Wire strip that is passed continuously adjacent to an electrostatically charged supply of said particles.
  • This mixture comprises a large plurality of particles 11 of an epoxy resin of a type known for electrical insulation coating or the constituents of such a resin.
  • a suitable epoxy resin comprises about 77.31 parts of Epi Rez #530 C, f9.59 parts Epi Rez #540, .23 part of hexarnethylene tetramine, 10.5 parts of trimellitic anhydride and .87 part of powdered silica (Cab-o-Sil, supplied by Godfrey L. Cabot, Inc.).
  • Epi Rez is supplied by the Celanese Plastics Company.
  • other resins suitable for electrodeposition may be used, of which polyolens, polyesters, polyacrylics, polyvinyls, polyamids, polyimids are listed by way of example.
  • the dielectric constant of these materials is preferably lower than 4 and invariably lower than 10.
  • Inorganic glasses and ceramics or blends thereof, that will be fused on a coated object can also comprise the particles 11 within the scope of our invention as can pigment particles which are known for use in the practice of xerography.
  • the epoxy particles 11 had the following mesh analyses-on mesh, 9.2%; on 200 mesh, 28.9%; on 230 mesh, 23.6%; on 270 mesh, 13.4%; on 325 mesh, 13.2%; on 400 mesh, 6.7%; through 400 mesh, 5%.
  • mesh analyses-on mesh 9.2%; on 200 mesh, 28.9%; on 230 mesh, 23.6%; on 270 mesh, 13.4%; on 325 mesh, 13.2%; on 400 mesh, 6.7%; through 400 mesh, 5%.
  • Interspersed uniformly among the particles 11 are particles 12 of barium titanate to the amount of about 1% of the Weight of the particles 11.
  • Barium titanate has a dielectric constant at room temperature of 1740 and a low dissipation factor (0.63%) which is advantageous in an electrical insulation.
  • the particle size of the barium titanate should be much iiner than the size of the particles 11 and all of it is passed through 400 mesh. Consequently, although the weight of the barium titanate added is relatively small the number of particles in the blend are sufficient to effect its behavior in an electric eld. It is preferred to have the high-dielectric-constant powder in a particle size from .01 to .05 mil.
  • the BaTiO3 be from 0.5-1.5% of the Weight of the particles 11 but weights from .1 to 5% may be used with advantageous effect depending on the relative particle sizes and selection of high-dielectric-constant material.
  • high-dielectric-constant materials that can be used in the practice of our invention include combinations of barium titanate and strontium titanate of which the compound with a barium:strontium ratio of 79:21 has a dielectric constant of 8700, that with a barium:strontium ratio of 71:29 has a dielectric constant of 2990 and that with a barium:strontium ratio of 90:10 has a dielectric constant of 1310.
  • the dissipation factor of the 79:21 barium strontium compound is high, 2.30%, but, because the quantity of the compound that will finally be fused into the insulation is low, the high dissipation factor will not be objectionable for many electrical insulation applications, and of course, will be no hindrance at all for nonelectrical coatings.
  • Ferrites are known with dielectric constants as high as 680,000 and these too are useful in the practice of our invention although their cost, at present, is high for many commercial applications.
  • a reel of rectangular magnet wire conductor 13, grounded at 14 is continuously advanced through a cloud 16 of electrostatically charged particles maintained by known methods around the conductor.
  • a suitable method employs a uid bed as hereinabove cited.
  • a high potential is maintained on a plate 17 by means of a transformerrectifier 18 or other suitable means in a known manner. Instead of the plate 17 the high potential might be applied to the nozzle of a powder spray unit of which several types are commercially available.
  • the cloud 16 is supplied from a mixer 19 which may also advantageously comprise a pulverizer, into which are paid the coating particles 21 CTI ' prise barium titanate.

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)
  • Paints Or Removers (AREA)

Description

Dec. s, 19,70
-W. W. PENDLETON Ef AL ELECTRODEPOSITION 0F PARTIGULATE COATING MATERIAL, r
Filed Nov. 7. 1967 United States Patent O M 3,546,017 ELECTRODEPOSITION OF PARTICULATE COATING MATERIAL Wesley W. Pendleton and William W. Ulmer, Muskegon,
Mich., assignors to Anaconda Wire and Cable Company, a corporation of Delaware Filed Nov. 7, 1967, Ser. No. 681,198 Int. Cl. H01b 3/00; B44d 1/094 U.S. Cl. 117-232 10 Claims ABSTRACT F THE DISCLOSURE Dielectric particles for electrostatic deposition are mixed with a small proportion of barium titanate or other high-dielectric-constant particles to increase the rate and efliciency of a coating process.
BACKGROUND OF THE INVENTION This invention relates to the coating of surfaces and particularly to the continuous coating of elongated conductors by electrostatic deposition. In application Ser. No. 588,511, now patent 3,396,699, an improvement is described in apparatus for electrostatically coating a continuous conductor passing through a cloud of particles above a fluid bed, and coating apparatus is commercially available in several varieties that operate on principles of electrostatics. In such apparatus an electrical potential, usually in the range of 30,000-l00,0\00 volts, is impressed between the object to be coated and an electrode spaced from the object. The coating particles are introduced between the electrode and the object and may become charged either by contact with the electrode, other charged particles, or the ionized air.
In the commercial use of electrostatic coating methods, including the practice of xerographic printing, it is,
of course, desirable to apply a given thickness of coating in as short a time as possible. The rate of application increases with an increased potential difference but a higher potential requires greater spacing of the electrode from the object being coated, and, where the particles are charged by contact with the electrode, a higher potential will then mean that the particles must travel a longer path.
It is not always possible to place the article being coated symmetrically with respect the electrode and it has been considered an advantage of the electrostatic method of coating that the particles will deposit around corners onto surfaces that are not in direct line with the particle supply source. This is particularly true in the case where a moving wire or strip is being coated in a cloud of particles above a fluid bed. In the commercial application of this method, however, the far surfaces have not always been uniformly coated when speeds were increased to those speeds wherein the near surfaces received a sufficient coating.
We seek therefore by our invention to obtain electrostatic depositions in shorter times.
We seek further, by our invention, to obtain coatings at lower potentials.
We seek, further, by our invention, to obtain more uniform electrostatically deposited coatings.
SUMMARY In a process for coating a surface by means of electrostatically charged particles, particularly particles having a dielectric constant under 10, we have invented the irnprovement of mixing among these particles a small percentage of a, preferably much iiner, particulate material, such, by preference, as barium titanate, having a dielectric constant, at the temperature of deposition, of at 3,546,017 Patented Dec. 8, 1970 least 1500. Our invention has particular application to the deposition of an organic resin, such as one comprising an epoxy, upon a continuously advancing conductor, such as a wire, and the subsequent fusing of the resin on the conductor.
Our invention comprises also the powdered mixture, for deposition, of particles of a coating material, and a small weight percentage of a substance, such as barium titanate, with a dielectric constant in excess of 1500. The barium titanate or other high-dielectric-constant substance is preferably substantially finer than the coating material. In certain preferred embodiments the coating material of our mixture comprises an organic resin such as an epoxy.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 represents a container of the mixture of our invention with the particle sizes very much enlarged.
FIG. 2 shows a scheme of the process of our invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. l a mixture, indicated generally by the numeral 10, has been prepared for coating the surface of an object such as an electrical Wire strip that is passed continuously adjacent to an electrostatically charged supply of said particles. This mixture comprises a large plurality of particles 11 of an epoxy resin of a type known for electrical insulation coating or the constituents of such a resin.
A suitable epoxy resin comprises about 77.31 parts of Epi Rez #530 C, f9.59 parts Epi Rez #540, .23 part of hexarnethylene tetramine, 10.5 parts of trimellitic anhydride and .87 part of powdered silica (Cab-o-Sil, supplied by Godfrey L. Cabot, Inc.). Epi Rez is supplied by the Celanese Plastics Company. Although we have described a mixture where the particles 11 comprise epoxy, other resins suitable for electrodeposition may be used, of which polyolens, polyesters, polyacrylics, polyvinyls, polyamids, polyimids are listed by way of example. The dielectric constant of these materials is preferably lower than 4 and invariably lower than 10. Inorganic glasses and ceramics or blends thereof, that will be fused on a coated object can also comprise the particles 11 within the scope of our invention as can pigment particles which are known for use in the practice of xerography.
In the preferred example the epoxy particles 11 had the following mesh analyses-on mesh, 9.2%; on 200 mesh, 28.9%; on 230 mesh, 23.6%; on 270 mesh, 13.4%; on 325 mesh, 13.2%; on 400 mesh, 6.7%; through 400 mesh, 5%. Generally we favor a particle size for the coating material from .5-3.5 mils in diameter.
Interspersed uniformly among the particles 11 are particles 12 of barium titanate to the amount of about 1% of the Weight of the particles 11. Barium titanate has a dielectric constant at room temperature of 1740 and a low dissipation factor (0.63%) which is advantageous in an electrical insulation. We prefer that the particle size of the barium titanate should be much iiner than the size of the particles 11 and all of it is passed through 400 mesh. Consequently, although the weight of the barium titanate added is relatively small the number of particles in the blend are sufficient to effect its behavior in an electric eld. It is preferred to have the high-dielectric-constant powder in a particle size from .01 to .05 mil. We prefer that the BaTiO3 be from 0.5-1.5% of the Weight of the particles 11 but weights from .1 to 5% may be used with advantageous effect depending on the relative particle sizes and selection of high-dielectric-constant material.
Other high-dielectric-constant materials that can be used in the practice of our invention include combinations of barium titanate and strontium titanate of which the compound with a barium:strontium ratio of 79:21 has a dielectric constant of 8700, that with a barium:strontium ratio of 71:29 has a dielectric constant of 2990 and that with a barium:strontium ratio of 90:10 has a dielectric constant of 1310. The dissipation factor of the 79:21 barium strontium compound is high, 2.30%, but, because the quantity of the compound that will finally be fused into the insulation is low, the high dissipation factor will not be objectionable for many electrical insulation applications, and of course, will be no hindrance at all for nonelectrical coatings. Ferrites are known with dielectric constants as high as 680,000 and these too are useful in the practice of our invention although their cost, at present, is high for many commercial applications.
It is noteworthy, however, that when TiO2, which has a dielectric constant of 100, was employed in the same manner as the BaTiO3 to improve powder deposition no improvement was observed.
In FIG. 2, in a preferred method of our invention, a reel of rectangular magnet wire conductor 13, grounded at 14 is continuously advanced through a cloud 16 of electrostatically charged particles maintained by known methods around the conductor. A suitable method employs a uid bed as hereinabove cited. A high potential is maintained on a plate 17 by means of a transformerrectifier 18 or other suitable means in a known manner. Instead of the plate 17 the high potential might be applied to the nozzle of a powder spray unit of which several types are commercially available. The cloud 16 is supplied from a mixer 19 which may also advantageously comprise a pulverizer, into which are paid the coating particles 21 CTI ' prise barium titanate.
3. The process of claim 1 wherein said heat fusible particles comprise an organic resin.
4. The process of claim 2 wherein said heat fusible particles comprise an organic resin.
5. The process of claim 1 wherein said particles are substantially finer in size than said powder.
6. The process of claim 2 wherein said barium titanate is substantially finer in size than said powder.
7. The process of insulating a conductor comprising the i steps of:
and a small proportion of high-dielectric-constant particles 22. In an oven 23 the coating is fused on the conductor which is then cooled and taken up on a reel 24.
When an epoxy resin was deposited on a copper strand passing through an electritied particle cloud at the rate of 30 ft./min. with an electrostatic potential of 100 kv., the wall thickness of insulation deposited was 2.0 to 2.4 mils. When .79% of barium titanate was added to an essentially similar epoxy powder the same rate of deposition was obtained at only 50 kv. potential and at 100 kv. the deposition was 4-5 mils. (In this experiment .21% of strontium titanate was also added but since the dielectric constant of this material is only 234 the barium titanate accounts for the improved deposition). When 2.5% of barium titanate was included (with no strontium titanate) a deposition of 6-7 mils was obtained at only 85 kv. at 36 ft./min.
We have invented a new and useful process and product of which the above description has been exemplary rather than definitive and for which we desire an award of Letters Patent.
We claim:
1. The process of coating an electrically conducting surface comprising the steps of:
(A) blending a mixture of electrostatically chargeable,
(A) applying a high electric potential between said conductor and an electrode spaced therefrom,
(B) blending a mixture of particles of a dielectric organic resin and 0.1% to 5% of the weight of said particles of particles of a material having a dielectric constant of at least 1500.
(C) introducing said mixture between said conductor and said electrode thereby depositing said particles of resin and said material upon said conductor, and
(D) fusing said resin particles upon the surface of said conductor.
8. The process of claim 7 wherein said conductor comprises a continuously advancing wire.
9. The process of claim 7 wherein said material comprises barium titanate.
10. The process of claim 7 wherein said resin comprises an epoxy.
References Cited UNITED STATES PATENTS 2,919,247 12/1959 Allen 252-621 3,203,821 8/1965 Domin' 117-17 3,239,465 3/1966 Rheinfrank 117-17.5 3,342,621 9/1967 Point et al. 117-17 FOREIGN PATENTS 3,563,663 12/1961 Japan 117-17 WILLIAM D. MARTIN, Primary Examiner 5 R. M. SPEER, Assistant Examiner U.S. C1. X.R. 117-17, 21, 224
go UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,546J 017 4 Dated 12/8/70 Inventods) Wesley W. Pendleton and William W. Ulmer It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:
rColumn l, line 47, after "respect" insert to.
Column 2, line 64, for "effect" read affect.
Claim 7, column 4 line 30, after 1500 change the period to '3. Coma was ma :32,1121:v B230 NI Anm:
mwN-Wh mm1. m nesting Offiwll'l dominican of Patent
US681198A 1967-11-07 1967-11-07 Electrodeposition of particulate coating material Expired - Lifetime US3546017A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US68119867A 1967-11-07 1967-11-07

Publications (1)

Publication Number Publication Date
US3546017A true US3546017A (en) 1970-12-08

Family

ID=24734235

Family Applications (1)

Application Number Title Priority Date Filing Date
US681198A Expired - Lifetime US3546017A (en) 1967-11-07 1967-11-07 Electrodeposition of particulate coating material

Country Status (2)

Country Link
US (1) US3546017A (en)
FR (1) FR1574585A (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3770482A (en) * 1971-01-18 1973-11-06 Beatrice Foods Co Electrostatic coating method of applying multilayer coating
US4025660A (en) * 1976-01-21 1977-05-24 W. R. Grace & Co. Method of masking, venting and coating the inside of a receptacle
US4100002A (en) * 1975-04-01 1978-07-11 Northern Telecom Limited Method for producing powder filled cable
US4109027A (en) * 1976-01-21 1978-08-22 W. R. Grace & Co. Electrostatic coating apparatus and method
US4131690A (en) * 1975-05-05 1978-12-26 Northern Electric Company Limited Method of powder coating an insulated electrical conductor
US4277389A (en) * 1979-11-05 1981-07-07 The Polymer Corporation X ray scattering device
EP0041824A1 (en) * 1980-06-11 1981-12-16 Associated Electrical Industries Limited A method of manufacturing electrical insulation
US4503284A (en) * 1983-11-09 1985-03-05 Essex Group, Inc. RF Suppressing magnet wire
US4605574A (en) * 1981-09-14 1986-08-12 Takashi Yonehara Method and apparatus for forming an extremely thin film on the surface of an object
US20140109716A1 (en) * 2012-10-22 2014-04-24 Shimano Inc. Bicycle control cable

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2556122B1 (en) * 1983-12-05 1986-09-12 Cables De Lyon Geoffroy Delore METHOD FOR MANUFACTURING AN INSULATOR WITH SELF-CROSS-LINKING CELLULAR STRUCTURE

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2919247A (en) * 1954-12-23 1959-12-29 Haloid Xerox Inc Tripartite developer for electrostatic images
US3203821A (en) * 1961-05-25 1965-08-31 Plate Gmbh Dr Flocks for the production of velvet-like or plush-like materials and process for theproduction of such materials by electrostatic means
US3239465A (en) * 1958-05-12 1966-03-08 Xerox Corp Xerographic developer
US3342621A (en) * 1962-08-03 1967-09-19 Sames Sa De Machines Electrost Electrostatic precipitation process

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2919247A (en) * 1954-12-23 1959-12-29 Haloid Xerox Inc Tripartite developer for electrostatic images
US3239465A (en) * 1958-05-12 1966-03-08 Xerox Corp Xerographic developer
US3203821A (en) * 1961-05-25 1965-08-31 Plate Gmbh Dr Flocks for the production of velvet-like or plush-like materials and process for theproduction of such materials by electrostatic means
US3342621A (en) * 1962-08-03 1967-09-19 Sames Sa De Machines Electrost Electrostatic precipitation process

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3770482A (en) * 1971-01-18 1973-11-06 Beatrice Foods Co Electrostatic coating method of applying multilayer coating
US4100002A (en) * 1975-04-01 1978-07-11 Northern Telecom Limited Method for producing powder filled cable
US4131690A (en) * 1975-05-05 1978-12-26 Northern Electric Company Limited Method of powder coating an insulated electrical conductor
US4025660A (en) * 1976-01-21 1977-05-24 W. R. Grace & Co. Method of masking, venting and coating the inside of a receptacle
US4109027A (en) * 1976-01-21 1978-08-22 W. R. Grace & Co. Electrostatic coating apparatus and method
US4277389A (en) * 1979-11-05 1981-07-07 The Polymer Corporation X ray scattering device
EP0041824A1 (en) * 1980-06-11 1981-12-16 Associated Electrical Industries Limited A method of manufacturing electrical insulation
US4605574A (en) * 1981-09-14 1986-08-12 Takashi Yonehara Method and apparatus for forming an extremely thin film on the surface of an object
US4503284A (en) * 1983-11-09 1985-03-05 Essex Group, Inc. RF Suppressing magnet wire
US20140109716A1 (en) * 2012-10-22 2014-04-24 Shimano Inc. Bicycle control cable

Also Published As

Publication number Publication date
FR1574585A (en) 1969-07-11

Similar Documents

Publication Publication Date Title
US3546017A (en) Electrodeposition of particulate coating material
US2321587A (en) Electrical conductive coating
DE69530602T2 (en) DEVICE AND METHOD FOR COATING SUBSTRATES WITH RESIN POWDER PARTICLES CHARGED BY INDUCTION
EP0789632B1 (en) Process for improving the electrostatic charge on powders
EP1569760B1 (en) Powder coating process
EP1569761B1 (en) Powder coating apparatus and process
US5731043A (en) Triboelectric coating powder and procees for coating wood substrates
TWI243716B (en) Powder coating process
US5756164A (en) Triboelectric coating powder and process
US2386634A (en) Flexible electrical insulating layer
US3021077A (en) Electrostatic coating apparatus
GB654362A (en) Improvements in electrophoretic deposition
GB655763A (en) Improvements in or relating to the electrophoretic coating of articles of electrically conducting material
ES2136882T5 (en) PROCEDURE FOR COATING A SUBSTRATE WITH A COMPOSITION OF POWDER PAINT.
US3617379A (en) Electrical insulation coating containing particles of inorganic substance of dielectric constant no less than 1500
US3832226A (en) Method for dry electrostatic coating
US2865789A (en) Electrostatic spray coating system
JPS58150218A (en) Method of producing insulated wire by static powder coating process
US5800605A (en) Process for the preparation of electrostatically charged particles
DE2306159C3 (en) Electrophotographic recording material
CA2201878C (en) Process for imparting an electrostatic charge to powders to render them useful for coating applications
DE541580C (en) Arbitrary resistance, carbon-containing resistance body for direct or alternating current for the derivation of these currents superimposed alternating currents of high frequencies
SU596297A1 (en) Method of electrostatic application of polymer powders onto metal articles
GB2110121A (en) Electrostatic spray coating
JPS58123611A (en) Method of producing insulated wire

Legal Events

Date Code Title Description
AS Assignment

Owner name: ATLANTIC RICHFIELD COMPANY, A PA CORP.

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ANACONDA COMPANY THE, A DE CORP;REEL/FRAME:003992/0218

Effective date: 19820115