US3681511A

US3681511A - Uses of and improvements in the coating of substrates

Info

Publication number: US3681511A
Authority: US
Inventors: George T Miller
Original assignee: Hooker Chemical Corp
Current assignee: Occidental Chemical Corp
Priority date: 1970-09-22
Filing date: 1970-09-22
Publication date: 1972-08-01
Anticipated expiration: 1989-08-01

Abstract

A process comprising subjecting a substrate to a member of the group of elemental phosphorus and low oxidation state phosphorus compounds, and thereafter to a metal salt or complex thereof, is employed to provide a coating on the substrate, for use in the production of electrostatic and magnostatic shielded wires and antistatic textiles. Additional improvements in the coating of filaments are provided for by subjection of the substrate to a solution of elemental phosphorus, molten elemental phosphorus, and thereafter to the metal salt or complex thereof, and also by employing a second metal salt bath.

Description

United States Patent Miller [54] USES OF AND IMPROVEMENTS IN THE COATING OF SUBSTRATES [72] Inventor: George T. Miller, Lewiston, NY.

[63] Continuation-impart of Ser. No. 860,424, Sept.

[52] US. Cl. ..174/36, 106/1, 156/2, 117/47 A, ll7/l28.4, 117/160 R, 174/102 R,

[51] Int. Cl ..H01b 1l/06, B44d l/092, C23c 3/02 [58] Field of Search....l 17/47 A, 47 R, 160 R, 128.4;

[56] References Cited UNITED STATES PATENTS 2,708,215 5/1955 Kaganoff ..l l7/128.4 3,574,070 4/1971 Sahely ..156/2 3,479,160 ll/l969 Klinger et a1. .,..l56/2 [4 1 Aug. 1, 1972 Bayard J. .l., Electrodeposition on Plastic Materials in Metal Industry, May 1940 p. 256.

Primary Examiner-Alfred L. Leavitt Assistant Examiner-Janyce A. Bell Attorney-Peter F. Casella, Donald C. Studley, Richard P. Mueller and James F. Mudd 5 7] ABSTRACT A process comprising subjecting a substrate to a member of the group of elemental phosphorus and low oxidation state phosphorus compounds, and thereafter to a metal salt or complex thereof, is employed to provide a coating on the substrate, for use in the production of electrostatic and magnostatic shielded wires and antistatic textiles. Additional improvements in the coating of filaments are provided for by subjection of the substrate to a solution of elemental phosphorus, molten elemental phosphorus, and thereafter to the metal salt or complex thereof, and also by employing a second metal salt bath.

13 Claims, No Drawings USES OF AND IMPROVEMENTS IN THE COATING OF SUBSTRATES REFERENCE TO PRIOR APPLICATION This is a continuation-in-part of copending application Ser. No. 860,424, filed Sept. 23, 1969. 7

BACKGROUND OF THE INVENTION There is as rapidly increasing demand for metal plated articles, for example, in the production of lowcost plastic articles that have a metallic function and appearance. Such articles are in demand in such industries as automotive, home appliance, radio and television and in the use of decorative containers and the like.

Heretofore, the utility of metallizing non-metallic substrates has been limited by the difficulty of forming an adherent bond with the metallic coating. Difficulty has been encountered in obtaining a uniform metallic coating on the substrate that represents a good combination of flexibility and adhesion. Further difficulty has also been encountered in attaining a good adherent bond when the substrate is of minimal thickness, such as a filament. As a result, the utility of metallized substrates, in any application wherein they would be subject to stretching and/or flexing, or wherein the substrate is of minimal thickness, has been diminished.

The present invention provides a process which eliminates the previous difficulties of metallic coated substrates and provides for electrostatic and magnostatic shielding of wires and antistatic textiles.

It is the object of this invention to provide an improved process for the metallic coating of filaments and substrates. Another object of this invention is to provide an improved process for the metallic coating of filaments and substrates wherein the resulting filaments or substrate can be stretched and/or flexed. It is also an object of this invention to provide for the electrostatic and magnostatic shielding or wires and a process for rendering textiles antistatic.'These and other objects will become apparent to one skilled in the art from the following disclosure.

SUMMARY OF THE INVENTION This invention relates to the use of and improvements in the metallizing of substrates. More particularly, this invention relates to an improved process, comprising subjecting a substrate to a member of the group of elemental phosphorus and low oxidation state phosphorus compounds, and thereafter to a metal salt or complex thereof which is employed to provide coatings on the substrate for the production of electrostatic and magnostatic shielded wire and anti-static textiles. Additional improvements in the metallic coating of filaments are provided for by subjection of the substrate to a solution of elemental phosphorus, molten elemental phosphorus, and thereafter to the metal salt or complex thereof, and also by employing a second metal salt bath.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The process of this invention is applicable to substrates, such as plastics and to other substantially nonmetallic substrates. Suitable substrates include, but are polyethylene,

not limited to, cellulosic and ceramic materials such as cloth, paper, wood, cork, cardboard, clay porcelain, leather, porous glass, asbestos, cement, and the like.

Typical plastics to which the process of this invention is applicable include the homopolymers and copolymers of ethylenically unsaturated aliphatic, alicyclic and aromatic hydrocarbons such as polypropylene, polybutene, ethylenepropylene copolymers; copolymers of ethylene or propylene or with other olefins, polybutadiene; polymers of butadiene, polyisoprene, both natural and synthetic, polystyrene including high impact polystyrene and polymers of pentene, hexene, heptene, octene, Z-methylpropene, 4-methyl-hexene-l, bicyclo- (2.2.l)-2-heptene, pentadiene, hexadiene, 2,3- dimethylbutadienel ,3,4-vinyl-cyclohexene, cyclopentadiene, methylstyrene, and the like. Other polymers useful in the invention include polyhalogenated as polytetrafluoroethylene;

polysilicone and polyhalogenated silicones; polyindene, indenecou marone resins; polymers or acrylate esters and polymers of methacrylate esters, acrylate and methacrylate resins such as ethyl acrylate, n-butyl methacrylate, isobutyl methacrylate, ethyl methacrylate and methyl methacrylate; alkyd resins; cellulose derivatives such as cellolose acetate, cellulose acetate butyrate, cellulose nitrate, ethyl cellulose, hydroxyethyl cellulose, methyl cellulose and sodium carboxymethyl cellulose; epoxy resins; furan resins (furfuryl alcohol or furfuralketone); hydrocarbon resins from petroleum; isobutylene resins (polyisobutylene); isocyanate resins (polyurethanes); melamine resins such as melamine-formaldehyde and melamine-urea-formaldehyde; oleo-resins; phenolic resins such as phenol-formaldehyde, phenolic-elastomer, phenolic-epoxy, phenolic-polyamide, and phenolic-vinyl acetals; polyamide polymers, such as polyamides,.polyamide-epoxy and particularly long chain synthetic polymeric amides containing recurring carbonamide groups as an integral part of the main polymer chain; polyacryl amides; polysulfones; polyester resins such as unsaturated polyesters of dibasic acids and dihydroxy compounds, and polyester elastomer and resorcinol resins such as resorcinol-formaldehyde, resorcinol-furfural, resorcinol-phenol-formaldehyde, resorcinol-polyamide and resorcinol-urea; rubbers such as natural rubber, synthetic polyisoprene, reclaimed rubber, chlorinated rubber, polybutadiene, cyclized rubber, butadieneacrylonitrile rubber, butadiene-styrene rubber, and butyl rubber; neoprene rubber' (polychloroprene); polysulfides (Thiokol); terpene resins; urea resins; vinyl resins such as polymers of vinyl acetal, vinyl acetate or vinyl alcohol-acetate copolymer, vinyl al- I as graft copolymers or polybutadiene, styrene and acrylonitrile, commonly called ABS resins; ABS- polyvinyl chloride polymers; acrylic polyvinyl chloride polymers; and any other suitable natural and synthetic polymers.

The polymers of the invention can be used in the unfilled conditions, or with fillers such as glass fiber, glass powder, glass beads, asbestos, talc and other mineral fillers, wood flour and other vegetable fillers, carbon in its various forms, dyes, pigments, waxes and the like.

In the process of this invention, the substrate is subjected to a member of the group of elemental white phosphorus and low oxidation state phosphorus compounds, and thereafter to a metal salt or complex thereof. This process is described in copending applications Ser. No. 614,541, filed Feb. 8, 1967, Ser. No. 750,488, filed Aug. 6, 1968 and now abandoned, Ser.

' No. 750,477, filed Aug. 6, 1968 now U.S. Pat. No.

3,520,403, Ser. No. 855,037, filed Sept. 3, 1969 and now abandoned, Ser. No. 847,423, filed Aug. 4, 1969, and now abandoned and in Ser. No. 23,967, filed Mar. 30, 1970, which disclosures are hereby incorporated by reference.

The subjection to elemental white phosphorus, which includes the various impure or commercial grades sometimes referred to as yellow phosphorus, can be effected when the phosphorus is in the vapor phase, is a liquid, or is dissolved in a solvent. Suitable solvents or diluents'for the elemental phosphorus are solvents which dissolve elemental phosphorus and which preferably swell the surface of a plastic without detrimentally affecting the surface of the plastic. Such solvents include the halogenated hydrocarbons and halocarbons such as chloroform, methylchloroform, dichloroethylene, trichloroethylene, perchloroethylene, and the like: aromatic hydrocarbons such as benzene, toluene, xylene, and the like. The solution concentration is generally in the range from about 0.0001 weight percent of phosphorus based on the weight of the solution up to a saturated solution, and preferably from about 0.1 to about 2.5 percent. Generally the temperature is in the range of about 30 to 135 C., but preferably in the range of about 50 to 100 C. The contact time varies depending on the nature of the substrate, the solvent and temperature, but is generally in the range of about 1 second to 1 hour or more, preferably in the range of about 1 to minutes.

Alternatively, the substrate can be subjected to at least one low oxidation state phosphorus compound, i.e., wherein the phosphorus has a valence of less than 5, preferably in a solvent. Suitable low oxidation state compounds are trihydroxymethyl phosphine; phosphorus sesquisulfide; P H phosphine; diphosphine, hypophosphorus acid and salts thereof of the metals of Groups I, II and III; phosphorus acid and the salts thereof of the metals of Groups I, I1 and III, and low oxidation state phosphorus compounds prepared by reacting elemental phosphorus with a suitable nucleophilic reagent or organo metallic compound (including Grignard reagents). Suitable nucleophilic reagents include basic compounds having an unshared I pair of electrons on a carbon, oxygen, nitrogen, sulfur or phosphorus atom. The preferred nucleophilic reagents have the formula MZ wherein M is an alkali metal or alkaline earth metal and Z is hydroxide, alkoxide, amide,,sulfite, thiosulfate, mercaptide, cyanate, thiocyanate, cyanide, azide, and the like.

When a solution of phosphorus sesquisulfide is employed in the process it can be utilized as a vapor, or liquid or may be dissolved in a solvent. Suitable solvents or diluents for the phosphorus sesquisulfide are solvents that dissolve the phosphorus sesquisulfide and which preferably swell the surface of the substrate without detrimentally affecting it. Such solvents include the halogenated hydrocarbons and halocarbons such as chloroform, methyl chloroform, phenyl chloroform, dichloroethylene, trichloroethylene, perchloroethylene, trichloroethane, dichloropropane, ethyl dibromide, ethyl chlorobr'omide, propylene dibromide, monochlorobenzene, monochlorotoluene and the like; aromatic hydrocarbons such as benzene, toluene, xylene, ethyl benzene, naphthalene and the like; ketones such as acetone, methylethyl ketone, and the like; acetic acid; acetic acid-trichloroethylene mixtures; carbon disulfide; and the like.

When a solution of phosphorus sesquisulfide is employed in the process, the solution concentration is generally in the range from about 0.0001 weight percent of phosphorus sesquisulfide based on the weight of the solution up to a saturated solution, and preferably from about 0.5 to about 2.5 percent. Prior to contacting the substrate with the phosphorus sesquisulfide, liquid or solution, the surface of the substrate should be clean. When a solution is used, the solvent generally serves to clean the surface. A solvent wash may be desireable when liquid phosphorus sesquisulfide is employed. The phosphorus sesquisulfide treatment is generally conducted at a temperature below the softening point of the substrate, and below the boiling point of the solvent, if the solvent is used. Generally, the temperature is in the range of about 0 to 135 C., but preferably in the range of about 15 to C. The contact time varies depending on the nature of the substrate, the solvent and temperature, but is generally in the range of about one second to one hour or more, preferably in the range of about one to twenty minutes. The foregoing conditions described with respect to phosphorus sesquisulfide, generally also apply for the other phosphonic compounds.

The substrate can, if desired, be subjected to the solvent prior to subjection to the phosphorus or low oxidation state phosphorus compound in order to improve the quality of the resulting metal coating. It has been found that subjection of the substrate to the solvent hereinbefore disclosed prior to subjection to the phosphorus sesquisulfide has a very marked effect on the adhesion of the final metal plated article. The temperature of the solvent is directly related to the adhesion realized. Generally, the temperature is in the range of about 30 C. to the boiling point of the solvent, preferably about 50 to and higher than the temperature of the solution of phosphorus or phosphorus compound, if a solution is used. The contact time varies depending on the nature of the substrate, solvent and temperature but preferably is 1 to 15 minutes.

As a result of treatment with phosphorus or low oxidation state phosphorus compounds, the phosphorus or low oxidation state phosphorus compounds are deposited at the surface of the substrate. By this is meant that they can be located on the surface, em-

bedded in the surface and embedded beneath the surface of the substrate. The location of the elemental phosphorus or phosphorus compound is somewhat dependent on the action of the solvent on the surface if one is used.

Following the treatment with elemental phosphorus or low oxidation state phosphorus compound, the substrate can be rinsed with a solvent and can then be dried by merely exposing the substrate to the atmosphere or to inert atmospheres such as nitrogen, carbon dioxide, and the like, or by drying the surface with radiant heaters or in a conventional oven. Drying times can vary considerably, for example, from 1 second to 30 minutes or more, preferably 5 seconds to minutes, and preferably 5 to 120 seconds. The rinsing and drying steps are optional.

The thus-treated substrate is thereafter subjected to a solution of a metal salt or a complex of a metal salt which is capable of reacting with the elemental phosphorus to form a metal phosphide, or capable of reacting with the low oxidation state phosphorus compound to form a metal-phosphorus coating. The term metal phosphide, as used herein means the metalphosphorus coating which is formed at the surface of the substrate, the term metal-phosphorus coating means the coating which is formed at the surface of the substrate and the term metal-phosphorus-sulfur compound means the metal-phosphorus-sulfur coating which is found at the surface of the solution. The metals generally employed are those of Groups IB, llB, IVB, VB, VIB, VIIB and VIII of the Periodic Table ap pearing on pages 60-61 of Langes Handbook of Chemistry (revised 10th. Ed.). The perferred metals are copper, chromium, manganese, cobalt, nickel, titanium, zirconium, vanadium, tantalum, cadmium, tungsten, molybdenum, silver, zinc, and the like.

The metal salts that are used can contain a wide variety of anions. Suitable anions include the anions of mineral acids such as sulfate, chloride, nitrate, phosphate, chlorate, perchlorate, and the like. Also useful are the anions of organic acids such as forrnate, acetate, citrate, stearate, and the like. Generally, the anions of organic acids contain one to 18 carbon atoms. Some useful metal salts include copper sulfate, copper chloride, nickel sulfate, nickel chloride, and nickel cyanide.

The metal salts can be complexed with a complexing agent that produces a solution having a basic pH 7). Particularly useful are the ammoniacal complexes of the metal salts in which one to six ammonia molecules are complexed with the foregoing metal salts. Typical examples include NiSO .6NH NiCl .6NH;,, Ni(C H O H) 6Nl-l CuSO .6Nl-l CuCl .6Nl-l NiSO .3Nl-l CuSO .4 and the like. Other useful complexing agents include quinoline, amines, and pyridine.

The foregoing metal salts and their complexes are used in ionic media, preferably in aqueous solutions. However, non-aqueous media can be employed such as alcohols, for example, methanol, ethanol, butanol, and the like. Mixtures of alcohol and water can be used and ionic mixtures of alcohol with other miscible solvents of the types disclosed hereinbefore are also useful. The solution concentration is generally in the range from about 0.1 weight percent metal salt or complex based on the total weight of the solution up to a saturated solution, preferably from about 1 to about 10 weight percent metal salt or complex. The pH of the metal salt or complex solution can range from about 4 to 14, but is generally maintained in the basic range, i.e., greater than 7, and preferably from about 10 to about 13. Generally, the contact temperature is in the range of about 0 to 110 C., preferably from about 20 to C. The time of contact can vary considerably depending on the nature of the substrate, the characteristics of the metal salts employed and the contact temperature. However, the time of contact is generally in the range of about 0.1 to 30 minutes, preferably from about 5 to 10 minutes.

When the substrate is a filament or is of minimal thickness, (up to about 20 mils and generally in the range of about 0.5 to about 14.0 mils), and it is to be treated with elemental phosphorus, it has been found that the quality of the resulting metallic phosphide can be improved by subjecting the substrate first to a solution of elemental white phosphorus as hereinbefore described and thereafter to molten elemental white phosphorus. Generally, the substrate is subjected to the solution of elemental phosphorus for about 1 second to about 1 hour, preferably 1 to about 10 minutes, and thereafter subjected to the molten phosphorus for about 1 second to about 1 hour, preferably 0.5 to about 10 minutes. The resulting substrate is thereafter subjected to a metal salt or complex thereof as described hereinbefore.

Surprisingly, it has been found that when a substrate which has been treated as described hereinbefore is thereafter subjected to a second solution of a metal salt or complex thereof wherein the metal lies between silver and platinum inclusive in the electromotive series, the treated substrates can be stretched or flexed without losing their. conductivity. The metals of the second solution are silver, gold, palladium and platinum. The second metal salt bath can contain the metals as salts of the anions disclosed hereinbefore and can be complexed by the complexing agents described hereinbefore. Typical metal salts or complexes thereof employed in the second metal salt bath include silver nitrate, silver acetate, silver salicylate, silver perchlorate, Au O Au(CN) .3H O, PtCl mm platinum sulfate, chloroplatinic acid, and the like. The solution concentrations, subjection temperatures and contact times are as described hereinbefore with respect to the first metal salt bath. The metal of the second metal salt or complex thereof is different from the metal of the first metal salt or complex thereof.

The treated articles provided by the processes hereinbefore described can be employed to provide electrostatic and magnostatic shielding of cables and wires. Heretofore, such applications were restricted because of the rigidity of prior metal plated substrates or required specially designed cables such as the recently developed cable having a continuous helical groove scored into the surface of a polyethylene dielectric sheath. By wires or cables is meant a conductor such as a copper wire which is encased in a dielectric sheath of a substrate hereinbefore described or having a layer of such substrate upon the dielectric sheath. The wire or cable is subjected to the process hereinbefore described so as to provide a coating of about 1 micron to about 5 mils on the surface of the wire or cafabric fibers for metal salt deposition is not necessary to obtain antistatic conductivity. A continuous treated filament or filaments can be woven through the fabric or can be combined with the yarn during the weaving of the fabric or can be combined into the yarn. The treated filaments are incorporated into the fabric in an antistatic amount, i.e., in an amount sufficient to allow dissipation of static buildup. Generally, the treated filamerits comprise about 0.01 to about 50 weight percent based on the total weight of the fabric, preferably from about 0.05 to about percent.

The following examples illustrate certain preferred embodiments of the present invention. Unless otherwise indicated in this specification and claims, all parts and percentages used herein are by weight and all temperatures are in degrees centigrade.

EXAMPLE 1 A denier polypropylene monofilament (1.8 mils in diameter) was subjected for 2 minutes to molten phosphorus at 6065 C. and thereafter for 5 minutes to a 5 percent solution of nickelous acetate, also containing ammonium hydroxide and sodium hydroxide, at 70 C. A conductive metal phosphide was produced on the monofilament, however, the deposit was somewhat uneven.

EXAMPLE 2 Example 1 was repeated except that the molten phosphorus was replaced by a 2 percent solution of phosphorus in trichloroethylene at 65 C. and thereafter for 1 1/2 minutes to molten phosphorus at 65 C. The monofilament was then subjected for 5 minutes to a solution containing 5 percent nickelous acetate, 5 percent ammonium hydroxide and 1 percent sodium hydroxide at 75 C. A conductive, adherent, uniform nickel phosphide was produced at the surface of the substrate.

Comparison of Example l-4 show that the metal phosphide obtained when a combination of molten phosphorus and a solution of phosphorus employed is superior to that obtained when either treatment is employed individually.

EXAMPLE 5 A polypropylene disk was subjected to a 2 percent solution of white phosphorus in trichloroethylene for 3 minutes at 65 C. and thereafter to a solution containing nickel sulfate, ammonium hydroxide and ethylene glycol for 5 minutes at 80 C. The plastic was thereafter washed for 1 minute in water and then subjected to a solution containing 5 percent silver nitrate to which ammonium hydroxide had been added until the solution was clear in appearance and then adjusted to a pH of about 7.5 with 50 percent by volume nitric acid. The

. silver nitrate solution was maintained at 25 C. After 90 white phosphorus in trichloroethylene. A conductive metal phosphide was produced on the monofilament, however, the coverage of the filament was slightly uneven.

EXAMPLE 3 uniform metal phosphide was formed at the surface of the monofilament.

EXAMPLE 4 A 15 denier polypropylene monofilament was subjected for 1 H2 minutes to a 2 percent solution of white seconds, the polypropylene disk was removed and found to have obtained a shiny, silvery, adherent layer.

EXAMPLE 6 Two 15 denier polypropylene monofilaments (1.8 mils in diameter) were subjected for 2 minutes to a 2 percent solution of white phosphorus in trichloroethylene at 63 C. and then for 2 minutes to molten phosphorus at 63 C. The thus-treated substrate was subjected for '6 minutes to a solution containing nickelous acetate, ammonium hydroxide, and sodium hydroxide maintained at C. Thereafter one sample was subjected for 15 seconds to a solution of silver nitrate whichhad been adjusted to a pH of 7 by nitric acid and ammonium hydroxide. The conductivity of the samples was then determined to be 10K ohms for the sample treated with the silver nitrate and 300K ohms for the sample which was not treated with a silver nitrate (conductivity was measured over the entire length of the monofilaments). The samples were set aside to age and after about 24 hours the conductivities were redeterrnined over a 3 inch length. The sample treated with silver nitrate exhibited a resistance of 1,000K ohms and the sample which was not treated with silver nitrate exhibited a resistance of 500K ohms. However, it was found that the handling during this measurement was sufficient to break the conductivity of the deposit on the untreated sample causing it to be non-conductive while the conductivity of the sample treated with silver was not affected.

EXAMPLE 7 Several yards of nylon monofilament were subjected for 1 minute to a saturated solution of trihydroxymethylphosphine in a 1:1 benzeneethanol solution at 25 C. and then pressed dry. The treated monofilament was thereafter subjected for 2 minutes to a 5 percent silver nitrate and ammonium hydroxide solution at 9 55-60 C., rinsed and electroless nickel plated. The

treated filament was combined with nylon yarn and.

EXAMPLE 8 Polypropylene fibers were subjected for 2 minutes to a solution of perchloroethylene at 54 C., then air dried for 1 minute. The treated fibers were thereafter subjected for 5 minutes to 1 percent P 8 in perchloroethylene at 35 C. The thus treated fibers were air dried for 6 minutes and thereafter subjected for 10 minutes to a solution of 0.2M Agl. 16M ethylene diamine at 65 C. The thus treated fibers were thereafter air dried for 1 minute, distilled water rinsed for 1 minute and oven dried for 30 minutes at 85 C. The thus treated fibers were found conductive.

. In a similar manner polyester fibers were so treated, and the results obtained were equivalent thereto.

EXAMPLE 9' The filaments of Example 7 are combined with nylon yarn which is used to make a 6 X 12 inch hook rug on a polypropylene base. The rug has anti-static properties.

This Example is repeated except that prior to combination with the yarn, the treated filaments are immersed in an ammoniacal solution containing 7 percent silver nitrate at room temperature for 90 seconds. A rug with anti-static properties is produced.

EXAMPLE 10 A sample of Alpha No. 3053 wire (copper encased in polyvinyl chloride) was subjected to a 2 percent solution of white phosphorus in trichloroethylene at 65 C. for 1 minute. Thereafter the wire was subjected for 4 minutes to an ammoniacal solution of nickelous acetate containing excess ammonium hydroxide at 70 C. and then for 15 seconds to an ammoniacal solution containing 7 percent silver nitrate at room temperature. A 15/16 inch length of the treated wire was tested by removing the conductor from the treated insulation and the contacts of an ohm meter were held at the ends of the treated insulation. The insulation was then stretched and released several times and the resistance in ohms recorded. The results are given in Table 1.

The figures recorded when the insulation was returned to its original length were taken after the resistance attained a steady figure. The insulation was also stretched beyond its yield point and upon release of the pressure relaxed to a length of seventeen-sixteenths inch. The wire then had a resistance of 100K ohms for-a inch long portion of the insulation.

EXAMPLE 11 The untreated wire of Example 10 was subjected to a 2 percent solution of phosphorus in trichloroethylene at 65 C. and thereafter .to a 5 percent ammoniacal solution of nickel acetate at 75 C. It was found that upon stretching the insulation as described in Example 5, the conductivity of the metal phosphide was lost.

EXAMPLE l2 jected for 2 minutes to a room temperature solution which had been prepared by adding ammonium hydroxide to a mixture of 40 grams of water and 2 grams of silver nitrate until the solution was clear and then adding nitric acid dropwise until the pH was 7.5-8. The resulting adherently bound metal phosphide coating had a resistance of 50-200K ohms.

EXAMPLE 13 The polyvinylchloride jacket and wire braid shield were removed from a length of Alpha No. 1706 wire. The core of polyethylene insulated copper was subjected to a 2 percent solution of white phosphorus in trichloroethylene for 5 minutes at C., air-dried for 30 seconds at room temperature, subjected to a 10 percent solution of nickelous acetate and excess ammonium hydroxide for 12 minutes at 70 C., washed with distilled water and dried. An oscilloscope was used to test the shielding qualities of the resulting conductive surface against the interference of a high-voltage transformer. The treated substrate was about three times more effective than the original wire shield.

EXAMPLE 14 A length of military type RG-58 c/u wire was treated as in Example 13 except that the subjection to the phosphorus solution was 8 minutes at 61 C. and the subjection to the nickel solution was 25 minutes at 65 C. A 22 gauge copper wire was then wound spirally around the treated plastic to act as a drain wire. The treated wire was tested with an audiogenerator, coil and oscilloscope and compared with two lengths of RG-58 c/u wire. Table II shows the disturbing current, and the induced potential in rnillivolts of the grounded wire. The lengths tested are indicated in the headings.

EXAMPLE 15 A length of Alpha No. 3035 wire was subjected for 1 minute to a 2 percent solution of yellow phosphorus in trichloroethylene at 65 C. 4 minutes to a 5 percent solution of nickelous acetate, sodium hydroxide and excess ammonium hydroxide at 70 C. and seconds in a 7 percent ammoniacal silver nitrate solution at room temperature. The treated wire was washed in distilled water, dried and then tested for its electrostatic and magnostatic shielding capabilities in accordance with the shielding tests described in Gooding et al., Shielding of Communication Cables, which appeared as Paper 55-198 in the July 1955 issue of the AlEE Journal on page 378. The testing apparatus described therein was modified to the extent that the shielding was applied to each test wire separately.

Table III contains the results of the magnostatic test and shows the voltage pickup in millivolts of the treated wire and five commercial wires when the disturbing current was 42 millivolts at various frequencies. Table IV shows the voltage pickup in millivolts of the treated wire and five commercial wires in the electrostatic tests when the shielding was grounded and the disturbing voltage was 35 volts at several frequencies. Table V shows the voltage pickup in volts of the electrostatic tests when the shielding was not grounded and the disturbing voltage was 35 volts.

TABLE III Un- Treated treated Alpha Alpha Alpha Alpha Alpha Military Cycles No. No. No. No. No. RG-

3053 3053 1706 1741 2412 58c/u 200K 3.0 7.0 1.5 1.0 2.0 1.5 K 0.8 v1.0 0.8 0.8 0.6 0.4 2K 0.2 0.2 0.2 nil nil 0.2 0.2K nil nil nil nil nil nil TABLE IV Treated Untreated 1 Alpha Alpha Alpha Alpha Alpha Military Cycles No. 0. No. No. No. RF-58c/u 3053 3053* l706 1741 2412 200K 1.0 4.0 7.0 1.0 1.5 20K 0.2 3.9 5., 1.2 0.5 2K nil 3.9 5.0 1.3 0.6 0.2K nil 1.5 6.0 1.3 0.4

- Could not be grounded TABLEV Treated Untreated Alpha Alpha Alpha Alpha Alpha Military Cycles No. No. No. No. No. RG-58c/u 3053 3053 1706 1741 2412 200K 0.9 9.2 2.8 1.05 1.2 3.0 20K 0.8 7.8 2.4 0.9 1.1 2.7 211 0.7 7.2 2.2 0.8 11 2.6 0.2K 0.6 5.0 2.0 0.7 10 2.2

2 EXAMPLE 16 The polyvinyl chloride jacket and wire braid are removed from a length of Alpha No. 1706 wire and the polyethylene coated wire was immersed in a solution prepared by mixing one mole of white phosphorus and one mole of lithium ethoxide in 600 milliliters of ethanol. After 30 seconds in the low oxidation state phosphorus solution at room temperature, the treated article is washed with water for 30 seconds and immersed in a 5 percent ammoniacal solution of nickel chloride at room temperature for 10 minutes to form an electrostatic, and magnostatic shield on the treated substrate.

EXAMPLE 17 The outer copper braid shielding and PVC Jacket was stripped from military specification wire RG-58 c/u (a polyethylene insulated copper/tin wire of small diameter). The polyethylene insulated wire was immersed in a solution of perchloroethylene for 2 minutes at 65 C. and thereafter air dried for 1 minute. The thus treated wire was thereafter subjected to a solution of 1.0 percent P S in perchloroethylene for 10 minutes at 35 C., air dried for 6 minutes and thereafter subjected to a solution of 0.04M CuCl- ,0. 16M ethylene diamine] 0.32M NaOl-l for 15 minutes at 60 degrees centigrade. The thus treated wire was thereafter air dried for 1 minute, rinsed in distilled water for 1 minute and air dried for 30 minutes at 85 C. The above treatment process was thereafter repeated.

EXAMPLE 18 Military specification wire RG-58 c/u was treated in accordance with'Example 17 except that a solution of 0.02M AgNO:,, 0. 16M ethylene diamine was substituted for the 0.04M CuCl ,0.l6M ethylene diamine/0.32 M NaOH solution.

EXAMPLE 19 The wire treated in accordance with Example 17 and 18 were subjected to standard shielding tests using a These tests show that the treated wires were superior transmitted 35 volt potential. The following average shielding values were found:

P S lAg P s /Cu Frequency Pickup Frequency Pickup (cycles/sec) (millivolts) (cycles/sec.) (millivolts) 0.2K 0.02 0.2K 0.02 2.0K 0.02 2.0K 0.03 20.0K 0.04 20.0K 0.06 200.0K 0 l7 200.0K 0.20

Average resistance-5 ohms/inch Averag e resistancel,800' ohms/inch Various changes and modifications can be made in the process and products of this invention without departing from the spirit and scope of the invention. The various embodiments of the invention disclosed herein serve to further illustrate the invention but are not intended to limit it.

I claim:

1. A process for preparing an electrostatic and magnastatic shield for an electric conductor which com prises subjecting the insulation of said conductor to phosphorus sesquesulfide and subjecting the thustreated insulation to a metal salt or complex thereof,

wherein said metal is selected from Groups 18, 11B,

lVB, VB, VIB, V118, and VIII of the Periodic Table.

2. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 1.

3. The process of claim 1 wherein the metal salt is silver nitrate.

- 4. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 3.

5. The process of claim 1 wherein the metal salt is copper chloride.

6. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 5.

7. The process of claim 1 wherein the substrate is a plastic.

8. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 7.

9. The process of claim 10 wherein the plastic is a thermoplastic polymer.

10. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 9.

11. The process of claim 7 wherein at least one component of the plastic is polyethylene.

12. An electric conductor having electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 1 1.

13. The process of claim 7 wherein the substrate is pre-treated with a solvent.

g;;g UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3: :5 l Dated August 1, 197

Inventofls) George T. Mi 1 ler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the "Abstract", line 6, "magnostatic" should be magnetostatic Column l, lines 31, +0 and 55, "magnostatic" should be magnetostatic Column 2, line 28, "cel lolose" should be cellulose Column 3, line l6, after "1967" there should be inserted now abandoned line 18 and 19, "now U.S. -Pat. No. 3,520, +03" should be now abandoned line 22, after "1970" there should be inserted now U.S. Pat. No. 3,650,708

' II II Column 5, l1 ne 56, CuSO Q should be CuSO lNH Column 6, line 55, "magnostati c" should be magnetostatic Column 7, line 2, "magnostatic' should be magnetostatic Column l0, line 15, "created" should be coated Column l l lines 10 and 66, "magnostatic" should be magnetostatic Column l2, line 13, magnostatic should be magnetostatic Claim '1, lines l and 2; Claim 2, line 2; Claim line 2; Claim 6,

line 2; Claim 8, line 2; Claim l0, line 2; and Claim l2, line 2; in each instance, magnostati c should be magnetostatic Signed and sealed this 23rd day of January 1973..

(SEAL) Attest:

EDWARD M. FLETCHER,JR. Attesting Officer ROBERT GOTTSCHALK Commissioner of Patents P0405) UNITED STATES PATENT OFFICE 569) CERTIFICATE OF CORRECTION Patent No. 3, .5 l Dated A g s 1, 97

Inventofls) George T. Mi l ler It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the "Abstract", line 6, magnostatic"-should be magnetostatic Column 1, lines 3l, '+0 and 55, "magnostatic" should be magnetostatic Column 2, line 28, "cellolose should be cellulose Column 3, line 16, after "l967 there should be inserted now abandoned line l8 and l9, "now U.S. Pat. No. 3,520, I03" should be now abandoned line 22, after l970" there should be inserted now U.S. Pat. No. 3,650,708

Column 5, line 56, CuSO r should be CuS0 J-INH Column 6, line 55, "magnostatic should be magnetostatic- Column 7, line 2, magnostatic" should be magnetostatic Column 10, line 15, 'created" should be coated Column ll, line s l0 and 66, "magnostatic" should be magnetostatic Column l2, line 13, "magnostatic" should be magnetostatic Claim 1, lines 1 and 2; Claim 2, line 2; Cl aim l, line 2; Claim 6,

line 2; Claim 8, line 2; Claim l0, line 2; and Claim l2, line 2; in each instance, "magnostati c" should be magnetostati c Signed and sealed this 23rd day of January 1973..

(SEAL) Attest:

EDWARD MIFLETCHERJR. ROBERT GOTTSCHALK Attestlng Offlcer Commissioner of Patents

Claims

2. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 1.
3. The process of claim 1 wherein the metal salt is silver nitrate.
4. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 3.
5. The process of claim 1 wherein the metal salt is copper chloride.
6. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 5.
7. The process of claim 1 wherein the substrate is a plastic.
8. An electric conductor having an eLectrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 7.
9. The process of claim 10 wherein the plastic is a thermoplastic polymer.
10. An electric conductor having an electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 9.
11. The process of claim 7 wherein at least one component of the plastic is polyethylene.
12. An electric conductor having electrostatic and magnostatic shield on the insulation thereof, which shield is formed by the process as claimed in claim 11.
13. The process of claim 7 wherein the substrate is pre-treated with a solvent.