CA2147522A1 - Method of coating a substrate with copper - Google Patents
Method of coating a substrate with copperInfo
- Publication number
- CA2147522A1 CA2147522A1 CA002147522A CA2147522A CA2147522A1 CA 2147522 A1 CA2147522 A1 CA 2147522A1 CA 002147522 A CA002147522 A CA 002147522A CA 2147522 A CA2147522 A CA 2147522A CA 2147522 A1 CA2147522 A1 CA 2147522A1
- Authority
- CA
- Canada
- Prior art keywords
- substrate
- copper
- nonwoven web
- copper formate
- poly
- 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.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C18/00—Chemical coating by decomposition of either liquid compounds or solutions of the coating forming compounds, without leaving reaction products of surface material in the coating; Contact plating
- C23C18/14—Decomposition by irradiation, e.g. photolysis, particle radiation or by mixed irradiation sources
- C23C18/143—Radiation by light, e.g. photolysis or pyrolysis
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K3/00—Apparatus or processes for manufacturing printed circuits
- H05K3/10—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern
- H05K3/105—Apparatus or processes for manufacturing printed circuits in which conductive material is applied to the insulating support in such a manner as to form the desired conductive pattern by conversion of non-conductive material on or in the support into conductive material, e.g. by using an energy beam
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemically Coating (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
Abstract
Abstract of the Disclosure A method of coating a substrate with copper which involves applying to the substrate an aqueous copper formate solution and irradiating the substrate to which the copper formate solution has been applied with radiation from an excimer lamp having a wavelength effective to coat the substrate with copper.
Such radiation desirably has a wavelength of 172 nm. The aqueous copper formate solution includes water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator.
Such radiation desirably has a wavelength of 172 nm. The aqueous copper formate solution includes water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator.
Description
-~2147~22 , ~
~IETHOD OF COATING A SUBSTRATE Wll'H COPPER
Cross-Reference to Related Application The method of the present invention is described, but not claimed, in .. . ~
copending and commonly assigned Application Serial No. , entitled -~
CORONA-ASSISTED ELECTROSTATIC FILTRATION APPARATUS AND
METHOD and filed of even date in the names of Ronald Sinclair Nohr and John Gavin MacDonald.
Background of the Invention ~ -,: .
The present invention relates to a method of coating a substrate with copper.
, ~ - .
15The metallization of a substrate is, of course, well known. Typical -~
procedures include, by way of illustration only, electroplating; electroless or ~ ` -; chemical plating; vacuum deposition, such as ion plating and sputtering; metallo~
organic deposition; chemical vapor deposition; hot-dipped coating; cementation ; ~;
coating; liquid-carrier diffusion coating; flame- and arc-spraying; electrostatic 20powder coating; slurry coating; and mechanical cladding. Many of these ~ ~ -.. . .
; ~ procedures require metal, ceramic, or other substrates capable of withstanding high temperatures. Other procedures involve the use of high vacuum and/or high temperatures. These procedures work well for materials capable of withstanding ~ ~
; high temperatures or which are of a size such that they can be maintained in a ~ ;
~IETHOD OF COATING A SUBSTRATE Wll'H COPPER
Cross-Reference to Related Application The method of the present invention is described, but not claimed, in .. . ~
copending and commonly assigned Application Serial No. , entitled -~
CORONA-ASSISTED ELECTROSTATIC FILTRATION APPARATUS AND
METHOD and filed of even date in the names of Ronald Sinclair Nohr and John Gavin MacDonald.
Background of the Invention ~ -,: .
The present invention relates to a method of coating a substrate with copper.
, ~ - .
15The metallization of a substrate is, of course, well known. Typical -~
procedures include, by way of illustration only, electroplating; electroless or ~ ` -; chemical plating; vacuum deposition, such as ion plating and sputtering; metallo~
organic deposition; chemical vapor deposition; hot-dipped coating; cementation ; ~;
coating; liquid-carrier diffusion coating; flame- and arc-spraying; electrostatic 20powder coating; slurry coating; and mechanical cladding. Many of these ~ ~ -.. . .
; ~ procedures require metal, ceramic, or other substrates capable of withstanding high temperatures. Other procedures involve the use of high vacuum and/or high temperatures. These procedures work well for materials capable of withstanding ~ ~
; high temperatures or which are of a size such that they can be maintained in a ~ ;
2~ low pressure environment. The desire for lower temperature processes and moreflexibility in the choice of substrate eventually led to photo-induced deposition techniques, such as photochemical vapor deposition and laser-induced pyrolytic -. . .. .
and photolytic deposition of films from gas phase, liquids~ and thin metal-organic ~ ~
.::. . , .-films. ~ ~-, .
-21 4 7 a 2 2 The goals of lower temperatures and increased flexibility in the selectionof substrates were significantly aided by the development of the dielectric barrier discharge excimer lamp (also referred to hereinafter as "excimer lamp"). Such a lamp is described, for example, by U. Kogelschatz7 "Silent discharges for the 5 generauon of ultraviolet and vacuum ultraviolet excimer radiation," Pure & Appl.
Chem., 62, No. 9, pp. 1667-1674 (1990); and E. Eliasson and U. Kogelschatz, "WExcimerRadiationfromDielectric-BarrierDischarges,"Appl.Phys.B,46, pp. 299-303 (1988). Excimer lamps were developed by ABB Infocom Ltd., Lenzburg, Switzerland, and at the present time are available from Heraeus 10 Noblelight GmbH, Kleinostheim, Germany.
The excimer lamp emits incoherent. pulsed ultraviolet radiation. Such radiation has a very narrow bandwidth. i.e.. the half width is of the order of 5-15 nm. This emitted radiation is incoherent and pulsed, the frequency of the pulsesbeing dependent upon the frequency of the alternating current power supply whichtypically is in the range of from about 20 to about 300 kHz. An excimer lamp t,vpically is identified or referred to by the wavelength at which the maximum intensity of the radiation occurs, which convention is followed throughout this specification and the claims. Thus, in comparison with most other commercially useful sources of ultraviolet radiation which typically emit over the entire 20 ultraviolet sp?ectrum and even into the visible region. excimer lamp radiation is essentially monochromatic.
Excimers are unstable molecular complexes which occur only under extreme conditions, such as those temporarily existing in special types of gas discharge. Typical examples are the molecular bonds between two rare gaseous 25 atoms or between a rare gas atom and a halogen atom. Excimer complexes dissociate within less than a microsecond and, while they are dissociating, release their binding energy in the form of ultraviolet radiation. The dielectric barrier excimers in general emit in the range of from about 125 nm to about 500 nm, depending upon the excimer gas mixture.
.... ~ .. .
~ 2 1 ~ 7 ~ 2 2 : -A dielectric barrier discharge excimer lamp has been employed to forrn thin metal films on various substrates~ such as ceramics (e.g., aluminum nitrideand aluminum oxide), cardboard, glass, plastics (e.g., polyimide and teflon, andsynthetic fibers. See, for example, H. Esrom and G. Wahl, Chemtronics, 4, 216-223 (1989); H. Esrom et al., Chemtronics, 4, 202-208 (1989~; and Jun-Ying Zhang and Hilmar Esrom, Appl. Surf. Sci., 54, 465-471 (1991). The procedure employed involved first preparing a solution of palladium acetate in chloroform, typically at a concentration of 0.25 g per 30 ml of solvent. The solution then was used to coat a substrate. The coated substrate was irradiated in a vacuum chamber with a xenon (Xe~ ) excimer lamp emitting at a wavelength of 172 nanometers (nm), with or without a mask to prevent the radiation from reaching predetermined portions of the substrate. If a mask were used, the substrate was washed after irradiation. The irradiated substrate next was placedin an electroless solution, typically an electroless copper solution. After the desired amount of metal deposited from the bath onto the substrate, the substrate was removed from the solution, washed with water, and dried. The paUadium acetate solution reportedly can be replaced with palladium or copper acetylaceton-ate. While this procedure is effective, it involves multiple steps and, in most instances, requires the use of an expensive palladium salt.
Summary of the Invention ' In response to the discussed difflculties and problems encountered in the : f ipnor art, a new method of coating a substrate with copper has been discovered.
25 Such method involves applying to the substrate an aqueous copper formate solution and then irradiating the substrate to which the copper forrnate solution has been applied with radiation from an excimer lamp having a wavelength effective ~o coat the substrate with copper. Such radiation desirably has a wavelength of 172 nm and the irradiation is carried out in the absence of oxygen.
and photolytic deposition of films from gas phase, liquids~ and thin metal-organic ~ ~
.::. . , .-films. ~ ~-, .
-21 4 7 a 2 2 The goals of lower temperatures and increased flexibility in the selectionof substrates were significantly aided by the development of the dielectric barrier discharge excimer lamp (also referred to hereinafter as "excimer lamp"). Such a lamp is described, for example, by U. Kogelschatz7 "Silent discharges for the 5 generauon of ultraviolet and vacuum ultraviolet excimer radiation," Pure & Appl.
Chem., 62, No. 9, pp. 1667-1674 (1990); and E. Eliasson and U. Kogelschatz, "WExcimerRadiationfromDielectric-BarrierDischarges,"Appl.Phys.B,46, pp. 299-303 (1988). Excimer lamps were developed by ABB Infocom Ltd., Lenzburg, Switzerland, and at the present time are available from Heraeus 10 Noblelight GmbH, Kleinostheim, Germany.
The excimer lamp emits incoherent. pulsed ultraviolet radiation. Such radiation has a very narrow bandwidth. i.e.. the half width is of the order of 5-15 nm. This emitted radiation is incoherent and pulsed, the frequency of the pulsesbeing dependent upon the frequency of the alternating current power supply whichtypically is in the range of from about 20 to about 300 kHz. An excimer lamp t,vpically is identified or referred to by the wavelength at which the maximum intensity of the radiation occurs, which convention is followed throughout this specification and the claims. Thus, in comparison with most other commercially useful sources of ultraviolet radiation which typically emit over the entire 20 ultraviolet sp?ectrum and even into the visible region. excimer lamp radiation is essentially monochromatic.
Excimers are unstable molecular complexes which occur only under extreme conditions, such as those temporarily existing in special types of gas discharge. Typical examples are the molecular bonds between two rare gaseous 25 atoms or between a rare gas atom and a halogen atom. Excimer complexes dissociate within less than a microsecond and, while they are dissociating, release their binding energy in the form of ultraviolet radiation. The dielectric barrier excimers in general emit in the range of from about 125 nm to about 500 nm, depending upon the excimer gas mixture.
.... ~ .. .
~ 2 1 ~ 7 ~ 2 2 : -A dielectric barrier discharge excimer lamp has been employed to forrn thin metal films on various substrates~ such as ceramics (e.g., aluminum nitrideand aluminum oxide), cardboard, glass, plastics (e.g., polyimide and teflon, andsynthetic fibers. See, for example, H. Esrom and G. Wahl, Chemtronics, 4, 216-223 (1989); H. Esrom et al., Chemtronics, 4, 202-208 (1989~; and Jun-Ying Zhang and Hilmar Esrom, Appl. Surf. Sci., 54, 465-471 (1991). The procedure employed involved first preparing a solution of palladium acetate in chloroform, typically at a concentration of 0.25 g per 30 ml of solvent. The solution then was used to coat a substrate. The coated substrate was irradiated in a vacuum chamber with a xenon (Xe~ ) excimer lamp emitting at a wavelength of 172 nanometers (nm), with or without a mask to prevent the radiation from reaching predetermined portions of the substrate. If a mask were used, the substrate was washed after irradiation. The irradiated substrate next was placedin an electroless solution, typically an electroless copper solution. After the desired amount of metal deposited from the bath onto the substrate, the substrate was removed from the solution, washed with water, and dried. The paUadium acetate solution reportedly can be replaced with palladium or copper acetylaceton-ate. While this procedure is effective, it involves multiple steps and, in most instances, requires the use of an expensive palladium salt.
Summary of the Invention ' In response to the discussed difflculties and problems encountered in the : f ipnor art, a new method of coating a substrate with copper has been discovered.
25 Such method involves applying to the substrate an aqueous copper formate solution and then irradiating the substrate to which the copper forrnate solution has been applied with radiation from an excimer lamp having a wavelength effective ~o coat the substrate with copper. Such radiation desirably has a wavelength of 172 nm and the irradiation is carried out in the absence of oxygen.
'~ :
:--`` ` 2147522 The aqueous copper formate solution inciudes water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator. ~ ;; ;^
The substrate may be any object, regardless of the material from which it is made or its shape or size. Desirably, the substrate will be a nonwoven web.
S More desirably, the nonwoven web will be prepared from a thermoplastic polymer. ~ -~
The present invention contemplates the use of any surfactant which permits or aids the substrate to be completely wet by or coated with the copper formate ` - `~
solution. The surfactant also may function to assist in keeping the photo-redox -10 facilitator dispersed in the solution and/or in reducing or preventing crystallization of the copper formate. Thus, the surfactant also may serve to stabilize the , solution. In general. the surfactant can be any surfactant known to those having ` ~ ;
ordinary skill in the art, including anionic. cationic. and nonionic surfactants. -Desirably, the surfactant will be a nonionic surfactant. More desirably, the surfactant will be a polysiloxane polyether.
~. ....,~ ,~ .
The photo-redox facilitator may be any substance which permits or - ~`~
facilitates the photoreduction of Cull ions to metallic copper or Cu . The photo-redox facilitator may serve to prevent crystallization of the copper formate.
Alternatively, it may function as an intermediate in a series of oxidation- ;
reduction reactions which leads to the reduction of certain copper ions to metallic copper. An example of a suitable photo-redox facilitator is a protein or polypeptide, such as a gelatin. , :.: ..: ~, Brief Description of the Drawings ~ "~
. . ., : . :.. -. .
FIG. 1 is a diagrammatic representation of the excimer lamp employed in ; ` ~
the example. , ~ . ~
'~ . . ,.'.
:--`` ` 2147522 The aqueous copper formate solution inciudes water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator. ~ ;; ;^
The substrate may be any object, regardless of the material from which it is made or its shape or size. Desirably, the substrate will be a nonwoven web.
S More desirably, the nonwoven web will be prepared from a thermoplastic polymer. ~ -~
The present invention contemplates the use of any surfactant which permits or aids the substrate to be completely wet by or coated with the copper formate ` - `~
solution. The surfactant also may function to assist in keeping the photo-redox -10 facilitator dispersed in the solution and/or in reducing or preventing crystallization of the copper formate. Thus, the surfactant also may serve to stabilize the , solution. In general. the surfactant can be any surfactant known to those having ` ~ ;
ordinary skill in the art, including anionic. cationic. and nonionic surfactants. -Desirably, the surfactant will be a nonionic surfactant. More desirably, the surfactant will be a polysiloxane polyether.
~. ....,~ ,~ .
The photo-redox facilitator may be any substance which permits or - ~`~
facilitates the photoreduction of Cull ions to metallic copper or Cu . The photo-redox facilitator may serve to prevent crystallization of the copper formate.
Alternatively, it may function as an intermediate in a series of oxidation- ;
reduction reactions which leads to the reduction of certain copper ions to metallic copper. An example of a suitable photo-redox facilitator is a protein or polypeptide, such as a gelatin. , :.: ..: ~, Brief Description of the Drawings ~ "~
. . ., : . :.. -. .
FIG. 1 is a diagrammatic representation of the excimer lamp employed in ; ` ~
the example. , ~ . ~
'~ . . ,.'.
- 4 - ~
',"' ~', ,''"'.-' ' ~ ' , ' i ~,, -, ; , ; , ~
-'- ` 21~7322 Detailed Description of the Invention As used herein, the phrase "coating a substrate with copper" means the deposition on the substrate of a generally uniform layer of metallic copper, i.e., S copper having a zero valence state (Cu ). The layer of copper is not required to cover the entire surface or surfaces of the substrate.
The term "copper formate" means cupric or copper(II) (Cull) formate.
The term "formate" refers to the formate ion, HCO~
The terrn "radiation" is used herein to mean the incoherent, pulsed 10 ultraviolet radiation produced by the dielectric barrier discharge excimer lamp described earlier. In general, the wavelength of the radiation will be selected to effect the photoreduction of Cull ions to metallic copper. Where the wavelength is such that the radiation is absorbed by oxygen, the irradiation may be carriedout in the absence of oxygen.
As used herein, the terrn "substrate" is meant to include any object, regardless of the material from which it is made or its shape or size. Thus, thesubstrate can be made of any desired material. Although complex and/or irregular shapes can be used, it will be appreciated by those having ordinary skill in the art of photochemistry that it may be necessary to separately or simul~
20 taneously irradiate the various surfaces which may be present, especially if the substrate is not transparent to the excimer lamp radiation. For example, the substrate can be in sheet form, such as a film or a woven or nonwoven web.
Desirably, the substrate will be a nonwoven web.
In those embodiments in which the substrate is a nonwoven web, such 25 nonwoven web in general can be prepared by any of the means known to those having ordinary skill in the art. For example, the nonwoven web can be prepared by such processes as meltblowing, coforming, spunbonding, hydroentan-gling, carding, air-laying, and wet-forming.
~ -~- 2 1 4 7 ~ 2 2 - ~
The nonwoven web more typically wiil be a nonwoven web prepared by meltblowing, coforming, spunbonding, and the like. By way of illustration only, such processes are exemplified by the following references which are incorporated ~ i herein by reference~
S (a) meltblowing references include, by way of example, U.S. Patent Nos.
3,016,599 to R. W. Perry, Jr., 3,704,198 to J. S. Prentice, 3,755,S27 to J. P.
Keller et al., 3,849,241 to R. R. Butin et al., 3,978,185 to R. R. Butin et al.,and 4,663,220 to T. J. Wisneski et al. See, also, V. A. Wenee, "Superfine Thermoplastic Fibers", Industrial and Engineering Chemistrv, Vol. 48, No. 8, pp. 1342-1346 (1956); V. A. Wente et al., "Manufacture of Superfine Organic -;
Fibers", Navy Research Laboratory, Washington, D.C., NRL Report 4364 ~ ` ` .`~
(111437), dated May 25, 1954, United States Department of Commerce, Office of Technical Services; and Robert R. Butin and Dwight T. Lohkamp, "Melt Blowing - A One-Step Web Process for New Nonwoven Products", Journal of the Technical Association of the Pulp and Paper Industry, Vol. 56, No.4, pp. 74 77 (1973); i;;, ~b) coforming references include U.S. Patent Nos. 4,100,324 to R. A. ; ~
Anderson et al. and 4,118,531 to E. R. Hauser; and ~ N""-"
(c) spunbonding references include, among others, U.S. Patent Nos. ;
3,341,394 to Kinney, 3,655,862 to Dorschner et al., 3,692,618 to Dorschner et ~ `;
al., 3,705,068 to Dobo et al., 3,802,817 to Matsuki et al., 3,853,651 to Porte, : . ...
4,064,605 to Akiyama et al., 4,091,140 to Harmon, 4,100,319 to Schwartz, ~;`
4,340,563 to Appel and Morman, 4,405,297 to Appel and Morman, 4,434,204 :; tol Hartman et al., 4,627,811 to Greiser and Wagner, and 4,644,045 to Fowells.
When the substrate is a nonwoven web, the web can be comprised of -natural fibers or fibers prepared from synthetic materials. Natural fibers include, for example, cellulose and cellulose derivatives, wool, cotton, and the like.
Synthetic materials include thermosetting and thermoplastic polymers. The term ~-"polymer" is meant to include blends of two or more polymers and alternating, : ~;
- 6 - ~ ~
~ .....
. :. ". .
'. ', '"~ '~ '~,'.'`' ~ 2147c~22 ....
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random. block. and graft copolymers prepared from two or more different starting materials or monomers.
Examples of therrnosetting polymers include, by way of illustration only, alkyd resins, such as phthalic anhydride-glycerol resins, maleic acid-glycerol S resins, adipic acid-glycerol resins, and phthalic anhydride-pentaerythritol resins;
allylic resins, in which such monomers as diallyl phthalate, diallyl isophthalate diallyl maleate, and diallyl chlorendate serve as nonvolatile cross-linking agents in polyester compounds; amino resins, such as aniline-formaldehyde resins, ethylene urea-formaldehyde resins, dicyandiamide-formaldehyde resins, melamine-10 formaldehyde resins, sulfonamide-formaldehyde resins, and urea-formaldehyde resins; epoxy resins. such as cross-linked epichlorohydrin-bisphenol A resins;
phenolic resins, such as phenol-formaldehyde resins. including Novolacs and ~.
resols; and thermosetting polyesters. silicones. and urethanes.
Examples of thermoplastic polymers include, by way of illustration only, 15 end-capped polyacetals, such as poly(oxymethylene) or polyfor naldehyde, poly(trichloroacetaldehyde), poly(n-valeraldehyde), poly(acetaldehyde), po~
ly(propionaldehyde), and the like; acrylic polymers, such as polyacrylamide, poly(acrylic acid), poly(methacrylic acid), poly(ethyl acrylate), ?oly(methyl methacrylate), and the like; fluorocarbon polymers, such as poly(tetrafluoroethyle-20 ne), perfluorinated ethylene-propylene copolymers, ethylene-tetrafluoroethylene copolymers, poly(chlorotrifluoroethylene), ethylene-chlorotrifluoroethylene copolymers, poly(vinylidene fluoride), poly(vinyl fluoride), and the like;
polyamides, such as poly(6-aminocaproic acid) or poly( -caprolactam), po-Iy,(hexamethylene adipamide)? poly(hexamethylene sebacamide), poly(ll-amino-25 undecanoic acid), and the like; polyaramides, such as poly(imino-1,3-phenylenei-minoisophthaloyl) or poly(m-phenylene isophthalamide), and the like; parylenes, such as poly-p-xylylene, poly(chloro-~2-xylylene), and the like; polyaryl ethers, such as poly(oxy-2,6-dimethyl-1 ,4-phenylene) or poly(l2-phenylene oxide), and the like;polyarylsulfones, suchaspoly(oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-. '!. `
2 1 4 7 :~ 2 2 :~
1,4-phenyiene-isopropylidene-1.4-phenylene), poly(sulfonyi-1~4-phenyleneoxy~
1,4-phenylenesulfonyl-4,4'-biphenylene~, and the like; polycarbonates, such as poly(bisphenol A) or poly(carbonyldioxy-1,4-phenyleneisopropylidene-1,4-phenylene), and the like; polyesters, such as poly(ethylene terephthalate), poly(tetramethylene terephthalate), poly(cyclohexylene-1,4-dimethylene tere-phthalate) or poly(oxymethylene-1,4-cyclohexylenemethyleneoxyterephthaloyl), and the like; polyaryl sulfides, such as poly(~-phenylene sulfide) or poly(thio~1 ,4-phenylene), and the like; polyimides, such as poly(pyromellitimido-1,4-phenylene), and the like; polyolefins, such as polyethylene, polypropylene, poly(1-butene), poly(2-butene), poly(l-pentene), poly(2-pentene), poly(3-methyl-1 -pentene), poly(4-methyl- 1 -pentene), 1, 2-poly- 1, 3 -butadiene, 1, 4-poly- 1, 3 -butadiene, polyisoprene, polychloroprene, polyacrylonitrile, poly(vinyl acetate), poly(vinylidene chloride), polystyrene, and the like; copolymers of the forego-ing, such as acrylonitrile-butadiene-styrene (ABS) copolymers, and the like; andthe like.
In one aspect of the present invention, the nonwoven web will be prepared from a thermoplastic polymer; polyolefins are particularly desirable because of their commercial importance. Especially suitable polyolefins are those which ... ....
contain only hydrogen and carbon atoms and which are prepared by the addition polymerization of one or more unsaturated monomers. Examples of such polyolefins include, among others, polyethylene, polypropylene, poly(1-butene), poly(2-butene), poly(1-pentene), poly(2-pentene), poly(3-methyl-1-pentene), poly(4-methyl-1-pentene), 1,2-poly-1,3-butadiene, 1,4-poly-1,3-butadiene, polyisoprene, polystyrene, and the like.
The term " surfactant" is used herein to mean any surfactant which permits or aids the substrate to be completely wet by or coated with the copper formate solution. The surfactant also may function to assist in keeping the photo-redox facilitator dispersed in the solution and/or in reducing or preventing crystallization of the copper formate. Thus. the surfactant also may serve to stabilize the ~: ` .'.' ; ~: , 2147~2 ~ ~
solution. The type and amount of the surfactant employed will depend primarily upon the nature of the substrate. When the surface free energy of the substrate is lower than the surface tension of the copper forrnate solution, the type and amount of the surfactant will be selected to lower the surface tension of the 5 solution to approximate the surface free energy of the substrate. When the surface free energy of the substrate is approximately the same as or higher thanthe surface tension of the copper formate solution, wetting of the substrate normally will be spontaneous. In such cases, the type and amount of the surfactant will be selected to stabilize the solution.
In general, the surfactant can be any surfactant known to those having ordinary skill in the art, including anionic, cationic, and nonionic surfactants.
Examples of anionic surfactants include, among others, linear and branched-chain sodium alkvlbenzenesulfonates, linear and branched-chain alkyl sulfates, and linear and branched-chain alkyl ethoxy sulfates. Cationic surfactants include, by 15 way of illustration, tallow trimethylammonium chloride. Examples of nonionic surfactants, include, again by way of illustration only, alkyl polyethoxylates, polyethoxylated alkylphenols, fatty acid ethanol amides, complex polymers of ethylene oxide, propylene oxide, and alcohols, and polysiloxane polyethers.
Desirably, the surfactant will be a nonionic surfactant. More desirably, the 20 surfactant will be a polysiloxane polyether.
As used herein, the term "photo-redox facilitator" means any substance which perrnits or facilitates the photoreduction of Cull ions to metallic copper or Cu. Such photoreduction will not occur in the absence of the photo-redox facilitator. Without wishing to be bound by theory, copper formate undergoes 25 a photochemical electron transfer reaction to yield copper(I) ions and forrnate radical anion. The latter is a strong reducing agent, with an E of -1.9 volts, and is is believed to be the species responsible for the reduction of copper(I) ions to metallic copper. However, the role of the photo-redox facilitator is not known.
It may serve only to prevent crystallization of the copper formate. Or, it may : -2 1 ~ 7 ~ 2 2 . . ~ .
function as an in~ermediate in a series of oxidation-reduction reactions which leads to the reduction of copper~I) ions to metallic copper.
Desirably, the photo-redox facilitator will be a protein or polypeptide.
More desirably, the photo-redox facilitator will be a collagen-derived polypeptide.
S Most desirably, the photo-redox facilitator will be a gelatin.
The amounts of copper forrnate, surfactant, and photo-redox facilitator present in the copper formate solution generally are empirically selected to accomplish the deposition of copper on the substrate. As a practical matter, theconcentration of copper formate will be in a range of from about 1 to about 10 10 percent by weight, based on the volume of water employed to prepare the solution. The concentration of surfactant typically will be in a range of from ~ -, . . - . .
about 0.1 to about 1 percent by volume. again based on the volume of water employed to prepare the solution. The amount of photo-redox facilitator generally will be in a range of from about 0.1 to about 5 percent by weight, -based on the volume of water employed. In each case, however, lesser or greater ;
amounts can be used, if desired.
In carrying out the method of the present invention, the copper forrnate solution is applied to the substrate by any known means. Those having ordinary skill in the art will appreciate that the method of applying the solution will in part ; ~ -depend on the nature of the substrate. The substrate to which the copper formatesolution has been applied then is irradiated with radiation from an excimer lamphaving a wavelength sufficient to coat the substrate with copper. Such radiation ~ ' `
may be that emitted by a Xe~ excimer lamp having a wavelength of 172 nm. ;
In, some cases, it may be either desirable or necessary to irradiate more than one surface of the substrate, especially in cases where the substrate is not transparent ;
to the radiation. By way of illustration, it often is desirable to irradiate both surfaces of a nonwoven web in order to assure the deposition of copper on all of - -the fibers of which the web is composed. ;
.
~ 2 1 4 7 ~ 2 2 -- - :
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.: . ~
. .
Those having ordinary skill in the art will readily understand that the irradiation of the substrate desirably will be carried out in the absence of oxygen in those cases where oxygen significantly absorbs the excimer lamp radiation, such as radiation having a wavelength of 172 nm. This can be accomplished by any known means. For example, if the substrate to be irradiated is of a proper size, the substrate can be irradiated in an evacuated, i.e., vacuum, chamber. Insuch case the chamber typically is evacuated to a low pressure, such as 0.1 Torr, charged with nitrogen at atmospheric pressure, and re-evacuated to 0.1 Torr.
Alternatively, the substrate can be irradiated under an inert gas atmosphere, such as argon or helium.
The irradiation period selected generally will be determined by the amount of copper to be deposited. The deposition of copper occurs only under the influence of the radiation. This permits the control of the amount of copper deposited, although the amount of copper deposited also is influenced by the amount of copper forrnate present on the surface of the substrate.
The present invention is further described by the example which follows Such example, however, is not to be construed as limiting in any way either the spirit or the scope of the present invention.
.
Example An excimer lamp configured substantially as described by Kogelschatz and Eliasson et al., supra, was employed and is shown diagrammatically in FIG. 1.
With reference to E;IG. 1, the excimer lamp 100 consisted of three coaxial quartz .~ ~ .. ..
cylinders and two coaxial electrodes. The outer coaxial quartz cylinder 102 was ~ -fused at the ends thereof to a central coaxial quartz cylinder 104 to forrn an . .. - , . . .. .
annular discharge space 106. An excimer-forming gas mixture was enclosed in the annular discharge space 106. An inner coaxial quartz cylinder 108 was ~ ;. . -placed within the central cylinder 104. The inner coaxial electrode 110 consisted ~ . .
:.. ~ .: . ....
~ .~, .. ...
~- 2147S22 ;~-:
. . . , ~ . ..
of a wire wound around the inner cylinder 108. The outer coaxial electrode 112 consisted of a wire mesh having a plurality of openings 114. The inner coaxial ~
electrode 110 and outer coaxial electrode 112 were connected to a high voltage ~ - `
generator 116. Electrical discharge was maintained by applying an alternating - -;
high voltage to the coaxial electrodes 110 and 112. The operating frequency was 40 kHz, the operating voltage 10 kV. Cooling water was passed through the ~
inner coaxial quartz cylinder 108, thereby maintaining the temperature at the --outer surface of the lamp at less than about 120C. The resulting ultraviolet ~ - -radiation was emitted through the openings 114 as shown by lines 118. The lamp was used as an assembly of four lamps 100 mounted side-by-side in a parallel arrangement. ~ ;
The substrate employed was a spunbonded polypropylene nonwoven web prepared on pilot scale equipment essentially as described in U.S. Patent No. ~ ~-4,360,563. The web was thermally point-bonded and had a basis weight of 1 - - `
ounce per square yard (about 24 grams per square meter). ~ ' -:
A 3 x 5 inch (about 7.6 cm x 12.7 cm) sample of the nonwoven web was placed in copper formate solution prepared by dissolving S g of copper formate -(Aldrich Chemical Company, Milwaukee, Wisconsin), 0.5 ml of surfactant, and ; `
1 g of commercial edible gelatin (Kroger, colorless) in 100 ml of water. The 20 surfactant was a polysiloxane polyether having the formula, , ,. :~:.
H3C-Si~-(Si (})43-(Si~)5-Si-CH3 ,,,,, ,, CH3 CH3 CH~ CH
(CH~O(C7H4O)~(C3H6O)~H `
: "~
~ .... ..
: ~- ,';
,., ~:
21~7~22 The material had a number-average molecular weight of about 7,700, a weight-average molecular weight of about 17,700, a z-average molecular weight of about 27,700, and a polydispersity of about 2.3.
The nonwoven web sample was soaked in the copper formate solution for 5 30 seconds, removed from the solution, and passed without folding through an Atlas Laboratory Wringer having a S-lb (about 2.3-kg) nip setting (Atlas Electric Devices Company, Chicago, Illinois). Each side of the sample was exposed sequentially for three minutes in a vacuum chamber at 0.1 Torr to 172-nm radiation from a xenon (Xe~ ) excimer lamp system mounted horizontally. The 10 sample then was washed with water and allowed to dry.
The nonwoven web was coated with copper metal, yet retained the flexibility and hand of the original nonwoven web. The examination of individualfibers by a scanning electron microscope showed that each fiber was completely covered by a thin coating of copper.
While the specification has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterationsto, variations of, and equivalents to these embodiments. Accordingly, the scope of the present invention should be assessed as that of the appended claims and 20 any equivalents thereto.
,....... ~.,. .. ~
.... , " .. :.:...
.,.:: ;,; . ..
. :; ,~: ,.:. :. .:
;: ..... ...
.. :, ~: .
....~;., " . ;...:
.; I I -,. ~.. .~, ." .
; .. . . ..
. . ;~-, ..; ..
,~ . ". .
~ ~,. . :" ....
,.." ;,, " ,.,,~
,. ~ ;, .... ,..-,.
... . ........
' . ;'' -i '',','~' ' ....... ,~.i,,
',"' ~', ,''"'.-' ' ~ ' , ' i ~,, -, ; , ; , ~
-'- ` 21~7322 Detailed Description of the Invention As used herein, the phrase "coating a substrate with copper" means the deposition on the substrate of a generally uniform layer of metallic copper, i.e., S copper having a zero valence state (Cu ). The layer of copper is not required to cover the entire surface or surfaces of the substrate.
The term "copper formate" means cupric or copper(II) (Cull) formate.
The term "formate" refers to the formate ion, HCO~
The terrn "radiation" is used herein to mean the incoherent, pulsed 10 ultraviolet radiation produced by the dielectric barrier discharge excimer lamp described earlier. In general, the wavelength of the radiation will be selected to effect the photoreduction of Cull ions to metallic copper. Where the wavelength is such that the radiation is absorbed by oxygen, the irradiation may be carriedout in the absence of oxygen.
As used herein, the terrn "substrate" is meant to include any object, regardless of the material from which it is made or its shape or size. Thus, thesubstrate can be made of any desired material. Although complex and/or irregular shapes can be used, it will be appreciated by those having ordinary skill in the art of photochemistry that it may be necessary to separately or simul~
20 taneously irradiate the various surfaces which may be present, especially if the substrate is not transparent to the excimer lamp radiation. For example, the substrate can be in sheet form, such as a film or a woven or nonwoven web.
Desirably, the substrate will be a nonwoven web.
In those embodiments in which the substrate is a nonwoven web, such 25 nonwoven web in general can be prepared by any of the means known to those having ordinary skill in the art. For example, the nonwoven web can be prepared by such processes as meltblowing, coforming, spunbonding, hydroentan-gling, carding, air-laying, and wet-forming.
~ -~- 2 1 4 7 ~ 2 2 - ~
The nonwoven web more typically wiil be a nonwoven web prepared by meltblowing, coforming, spunbonding, and the like. By way of illustration only, such processes are exemplified by the following references which are incorporated ~ i herein by reference~
S (a) meltblowing references include, by way of example, U.S. Patent Nos.
3,016,599 to R. W. Perry, Jr., 3,704,198 to J. S. Prentice, 3,755,S27 to J. P.
Keller et al., 3,849,241 to R. R. Butin et al., 3,978,185 to R. R. Butin et al.,and 4,663,220 to T. J. Wisneski et al. See, also, V. A. Wenee, "Superfine Thermoplastic Fibers", Industrial and Engineering Chemistrv, Vol. 48, No. 8, pp. 1342-1346 (1956); V. A. Wente et al., "Manufacture of Superfine Organic -;
Fibers", Navy Research Laboratory, Washington, D.C., NRL Report 4364 ~ ` ` .`~
(111437), dated May 25, 1954, United States Department of Commerce, Office of Technical Services; and Robert R. Butin and Dwight T. Lohkamp, "Melt Blowing - A One-Step Web Process for New Nonwoven Products", Journal of the Technical Association of the Pulp and Paper Industry, Vol. 56, No.4, pp. 74 77 (1973); i;;, ~b) coforming references include U.S. Patent Nos. 4,100,324 to R. A. ; ~
Anderson et al. and 4,118,531 to E. R. Hauser; and ~ N""-"
(c) spunbonding references include, among others, U.S. Patent Nos. ;
3,341,394 to Kinney, 3,655,862 to Dorschner et al., 3,692,618 to Dorschner et ~ `;
al., 3,705,068 to Dobo et al., 3,802,817 to Matsuki et al., 3,853,651 to Porte, : . ...
4,064,605 to Akiyama et al., 4,091,140 to Harmon, 4,100,319 to Schwartz, ~;`
4,340,563 to Appel and Morman, 4,405,297 to Appel and Morman, 4,434,204 :; tol Hartman et al., 4,627,811 to Greiser and Wagner, and 4,644,045 to Fowells.
When the substrate is a nonwoven web, the web can be comprised of -natural fibers or fibers prepared from synthetic materials. Natural fibers include, for example, cellulose and cellulose derivatives, wool, cotton, and the like.
Synthetic materials include thermosetting and thermoplastic polymers. The term ~-"polymer" is meant to include blends of two or more polymers and alternating, : ~;
- 6 - ~ ~
~ .....
. :. ". .
'. ', '"~ '~ '~,'.'`' ~ 2147c~22 ....
. : ~
random. block. and graft copolymers prepared from two or more different starting materials or monomers.
Examples of therrnosetting polymers include, by way of illustration only, alkyd resins, such as phthalic anhydride-glycerol resins, maleic acid-glycerol S resins, adipic acid-glycerol resins, and phthalic anhydride-pentaerythritol resins;
allylic resins, in which such monomers as diallyl phthalate, diallyl isophthalate diallyl maleate, and diallyl chlorendate serve as nonvolatile cross-linking agents in polyester compounds; amino resins, such as aniline-formaldehyde resins, ethylene urea-formaldehyde resins, dicyandiamide-formaldehyde resins, melamine-10 formaldehyde resins, sulfonamide-formaldehyde resins, and urea-formaldehyde resins; epoxy resins. such as cross-linked epichlorohydrin-bisphenol A resins;
phenolic resins, such as phenol-formaldehyde resins. including Novolacs and ~.
resols; and thermosetting polyesters. silicones. and urethanes.
Examples of thermoplastic polymers include, by way of illustration only, 15 end-capped polyacetals, such as poly(oxymethylene) or polyfor naldehyde, poly(trichloroacetaldehyde), poly(n-valeraldehyde), poly(acetaldehyde), po~
ly(propionaldehyde), and the like; acrylic polymers, such as polyacrylamide, poly(acrylic acid), poly(methacrylic acid), poly(ethyl acrylate), ?oly(methyl methacrylate), and the like; fluorocarbon polymers, such as poly(tetrafluoroethyle-20 ne), perfluorinated ethylene-propylene copolymers, ethylene-tetrafluoroethylene copolymers, poly(chlorotrifluoroethylene), ethylene-chlorotrifluoroethylene copolymers, poly(vinylidene fluoride), poly(vinyl fluoride), and the like;
polyamides, such as poly(6-aminocaproic acid) or poly( -caprolactam), po-Iy,(hexamethylene adipamide)? poly(hexamethylene sebacamide), poly(ll-amino-25 undecanoic acid), and the like; polyaramides, such as poly(imino-1,3-phenylenei-minoisophthaloyl) or poly(m-phenylene isophthalamide), and the like; parylenes, such as poly-p-xylylene, poly(chloro-~2-xylylene), and the like; polyaryl ethers, such as poly(oxy-2,6-dimethyl-1 ,4-phenylene) or poly(l2-phenylene oxide), and the like;polyarylsulfones, suchaspoly(oxy-1,4-phenylenesulfonyl-1,4-phenyleneoxy-. '!. `
2 1 4 7 :~ 2 2 :~
1,4-phenyiene-isopropylidene-1.4-phenylene), poly(sulfonyi-1~4-phenyleneoxy~
1,4-phenylenesulfonyl-4,4'-biphenylene~, and the like; polycarbonates, such as poly(bisphenol A) or poly(carbonyldioxy-1,4-phenyleneisopropylidene-1,4-phenylene), and the like; polyesters, such as poly(ethylene terephthalate), poly(tetramethylene terephthalate), poly(cyclohexylene-1,4-dimethylene tere-phthalate) or poly(oxymethylene-1,4-cyclohexylenemethyleneoxyterephthaloyl), and the like; polyaryl sulfides, such as poly(~-phenylene sulfide) or poly(thio~1 ,4-phenylene), and the like; polyimides, such as poly(pyromellitimido-1,4-phenylene), and the like; polyolefins, such as polyethylene, polypropylene, poly(1-butene), poly(2-butene), poly(l-pentene), poly(2-pentene), poly(3-methyl-1 -pentene), poly(4-methyl- 1 -pentene), 1, 2-poly- 1, 3 -butadiene, 1, 4-poly- 1, 3 -butadiene, polyisoprene, polychloroprene, polyacrylonitrile, poly(vinyl acetate), poly(vinylidene chloride), polystyrene, and the like; copolymers of the forego-ing, such as acrylonitrile-butadiene-styrene (ABS) copolymers, and the like; andthe like.
In one aspect of the present invention, the nonwoven web will be prepared from a thermoplastic polymer; polyolefins are particularly desirable because of their commercial importance. Especially suitable polyolefins are those which ... ....
contain only hydrogen and carbon atoms and which are prepared by the addition polymerization of one or more unsaturated monomers. Examples of such polyolefins include, among others, polyethylene, polypropylene, poly(1-butene), poly(2-butene), poly(1-pentene), poly(2-pentene), poly(3-methyl-1-pentene), poly(4-methyl-1-pentene), 1,2-poly-1,3-butadiene, 1,4-poly-1,3-butadiene, polyisoprene, polystyrene, and the like.
The term " surfactant" is used herein to mean any surfactant which permits or aids the substrate to be completely wet by or coated with the copper formate solution. The surfactant also may function to assist in keeping the photo-redox facilitator dispersed in the solution and/or in reducing or preventing crystallization of the copper formate. Thus. the surfactant also may serve to stabilize the ~: ` .'.' ; ~: , 2147~2 ~ ~
solution. The type and amount of the surfactant employed will depend primarily upon the nature of the substrate. When the surface free energy of the substrate is lower than the surface tension of the copper forrnate solution, the type and amount of the surfactant will be selected to lower the surface tension of the 5 solution to approximate the surface free energy of the substrate. When the surface free energy of the substrate is approximately the same as or higher thanthe surface tension of the copper formate solution, wetting of the substrate normally will be spontaneous. In such cases, the type and amount of the surfactant will be selected to stabilize the solution.
In general, the surfactant can be any surfactant known to those having ordinary skill in the art, including anionic, cationic, and nonionic surfactants.
Examples of anionic surfactants include, among others, linear and branched-chain sodium alkvlbenzenesulfonates, linear and branched-chain alkyl sulfates, and linear and branched-chain alkyl ethoxy sulfates. Cationic surfactants include, by 15 way of illustration, tallow trimethylammonium chloride. Examples of nonionic surfactants, include, again by way of illustration only, alkyl polyethoxylates, polyethoxylated alkylphenols, fatty acid ethanol amides, complex polymers of ethylene oxide, propylene oxide, and alcohols, and polysiloxane polyethers.
Desirably, the surfactant will be a nonionic surfactant. More desirably, the 20 surfactant will be a polysiloxane polyether.
As used herein, the term "photo-redox facilitator" means any substance which perrnits or facilitates the photoreduction of Cull ions to metallic copper or Cu. Such photoreduction will not occur in the absence of the photo-redox facilitator. Without wishing to be bound by theory, copper formate undergoes 25 a photochemical electron transfer reaction to yield copper(I) ions and forrnate radical anion. The latter is a strong reducing agent, with an E of -1.9 volts, and is is believed to be the species responsible for the reduction of copper(I) ions to metallic copper. However, the role of the photo-redox facilitator is not known.
It may serve only to prevent crystallization of the copper formate. Or, it may : -2 1 ~ 7 ~ 2 2 . . ~ .
function as an in~ermediate in a series of oxidation-reduction reactions which leads to the reduction of copper~I) ions to metallic copper.
Desirably, the photo-redox facilitator will be a protein or polypeptide.
More desirably, the photo-redox facilitator will be a collagen-derived polypeptide.
S Most desirably, the photo-redox facilitator will be a gelatin.
The amounts of copper forrnate, surfactant, and photo-redox facilitator present in the copper formate solution generally are empirically selected to accomplish the deposition of copper on the substrate. As a practical matter, theconcentration of copper formate will be in a range of from about 1 to about 10 10 percent by weight, based on the volume of water employed to prepare the solution. The concentration of surfactant typically will be in a range of from ~ -, . . - . .
about 0.1 to about 1 percent by volume. again based on the volume of water employed to prepare the solution. The amount of photo-redox facilitator generally will be in a range of from about 0.1 to about 5 percent by weight, -based on the volume of water employed. In each case, however, lesser or greater ;
amounts can be used, if desired.
In carrying out the method of the present invention, the copper forrnate solution is applied to the substrate by any known means. Those having ordinary skill in the art will appreciate that the method of applying the solution will in part ; ~ -depend on the nature of the substrate. The substrate to which the copper formatesolution has been applied then is irradiated with radiation from an excimer lamphaving a wavelength sufficient to coat the substrate with copper. Such radiation ~ ' `
may be that emitted by a Xe~ excimer lamp having a wavelength of 172 nm. ;
In, some cases, it may be either desirable or necessary to irradiate more than one surface of the substrate, especially in cases where the substrate is not transparent ;
to the radiation. By way of illustration, it often is desirable to irradiate both surfaces of a nonwoven web in order to assure the deposition of copper on all of - -the fibers of which the web is composed. ;
.
~ 2 1 4 7 ~ 2 2 -- - :
`,.. -` :; .
.: . ~
. .
Those having ordinary skill in the art will readily understand that the irradiation of the substrate desirably will be carried out in the absence of oxygen in those cases where oxygen significantly absorbs the excimer lamp radiation, such as radiation having a wavelength of 172 nm. This can be accomplished by any known means. For example, if the substrate to be irradiated is of a proper size, the substrate can be irradiated in an evacuated, i.e., vacuum, chamber. Insuch case the chamber typically is evacuated to a low pressure, such as 0.1 Torr, charged with nitrogen at atmospheric pressure, and re-evacuated to 0.1 Torr.
Alternatively, the substrate can be irradiated under an inert gas atmosphere, such as argon or helium.
The irradiation period selected generally will be determined by the amount of copper to be deposited. The deposition of copper occurs only under the influence of the radiation. This permits the control of the amount of copper deposited, although the amount of copper deposited also is influenced by the amount of copper forrnate present on the surface of the substrate.
The present invention is further described by the example which follows Such example, however, is not to be construed as limiting in any way either the spirit or the scope of the present invention.
.
Example An excimer lamp configured substantially as described by Kogelschatz and Eliasson et al., supra, was employed and is shown diagrammatically in FIG. 1.
With reference to E;IG. 1, the excimer lamp 100 consisted of three coaxial quartz .~ ~ .. ..
cylinders and two coaxial electrodes. The outer coaxial quartz cylinder 102 was ~ -fused at the ends thereof to a central coaxial quartz cylinder 104 to forrn an . .. - , . . .. .
annular discharge space 106. An excimer-forming gas mixture was enclosed in the annular discharge space 106. An inner coaxial quartz cylinder 108 was ~ ;. . -placed within the central cylinder 104. The inner coaxial electrode 110 consisted ~ . .
:.. ~ .: . ....
~ .~, .. ...
~- 2147S22 ;~-:
. . . , ~ . ..
of a wire wound around the inner cylinder 108. The outer coaxial electrode 112 consisted of a wire mesh having a plurality of openings 114. The inner coaxial ~
electrode 110 and outer coaxial electrode 112 were connected to a high voltage ~ - `
generator 116. Electrical discharge was maintained by applying an alternating - -;
high voltage to the coaxial electrodes 110 and 112. The operating frequency was 40 kHz, the operating voltage 10 kV. Cooling water was passed through the ~
inner coaxial quartz cylinder 108, thereby maintaining the temperature at the --outer surface of the lamp at less than about 120C. The resulting ultraviolet ~ - -radiation was emitted through the openings 114 as shown by lines 118. The lamp was used as an assembly of four lamps 100 mounted side-by-side in a parallel arrangement. ~ ;
The substrate employed was a spunbonded polypropylene nonwoven web prepared on pilot scale equipment essentially as described in U.S. Patent No. ~ ~-4,360,563. The web was thermally point-bonded and had a basis weight of 1 - - `
ounce per square yard (about 24 grams per square meter). ~ ' -:
A 3 x 5 inch (about 7.6 cm x 12.7 cm) sample of the nonwoven web was placed in copper formate solution prepared by dissolving S g of copper formate -(Aldrich Chemical Company, Milwaukee, Wisconsin), 0.5 ml of surfactant, and ; `
1 g of commercial edible gelatin (Kroger, colorless) in 100 ml of water. The 20 surfactant was a polysiloxane polyether having the formula, , ,. :~:.
H3C-Si~-(Si (})43-(Si~)5-Si-CH3 ,,,,, ,, CH3 CH3 CH~ CH
(CH~O(C7H4O)~(C3H6O)~H `
: "~
~ .... ..
: ~- ,';
,., ~:
21~7~22 The material had a number-average molecular weight of about 7,700, a weight-average molecular weight of about 17,700, a z-average molecular weight of about 27,700, and a polydispersity of about 2.3.
The nonwoven web sample was soaked in the copper formate solution for 5 30 seconds, removed from the solution, and passed without folding through an Atlas Laboratory Wringer having a S-lb (about 2.3-kg) nip setting (Atlas Electric Devices Company, Chicago, Illinois). Each side of the sample was exposed sequentially for three minutes in a vacuum chamber at 0.1 Torr to 172-nm radiation from a xenon (Xe~ ) excimer lamp system mounted horizontally. The 10 sample then was washed with water and allowed to dry.
The nonwoven web was coated with copper metal, yet retained the flexibility and hand of the original nonwoven web. The examination of individualfibers by a scanning electron microscope showed that each fiber was completely covered by a thin coating of copper.
While the specification has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterationsto, variations of, and equivalents to these embodiments. Accordingly, the scope of the present invention should be assessed as that of the appended claims and 20 any equivalents thereto.
,....... ~.,. .. ~
.... , " .. :.:...
.,.:: ;,; . ..
. :; ,~: ,.:. :. .:
;: ..... ...
.. :, ~: .
....~;., " . ;...:
.; I I -,. ~.. .~, ." .
; .. . . ..
. . ;~-, ..; ..
,~ . ". .
~ ~,. . :" ....
,.." ;,, " ,.,,~
,. ~ ;, .... ,..-,.
... . ........
' . ;'' -i '',','~' ' ....... ,~.i,,
Claims (19)
1. A method of coating a substrate with copper which comprises:
applying to the substrate an aqueous copper formate solution; and irradiating the substrate to which the copper formate solution has been applied with radiation from an excimer lamp having a wavelength effective to coat the substrate with copper;
in which the aqueous copper formate solution comprises water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator.
applying to the substrate an aqueous copper formate solution; and irradiating the substrate to which the copper formate solution has been applied with radiation from an excimer lamp having a wavelength effective to coat the substrate with copper;
in which the aqueous copper formate solution comprises water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator.
2. The method of claim 1, in which the irradiation of the substrate is carried out in the absence of oxygen.
3. The method of claim 2, in which the wavelength of the radiation from the excimer lamp is 172 nanometers.
4. The method of claim 1, in which the surfactant is a polysiloxane polyether.
5. The method of claim 1, in which the photo-redox facilitator is a protein or polypeptide.
6. The method of claim 1, in which the photo-redox facilitator is a collagen-derived polypeptide.
7. The method of claim 6, in which the collagen-derived polypeptide is a gelatin.
8. The method of claim 1, in which the substrate is a sheet.
9. The method of claim 1, in which the substrate is a film.
10. A method of coating a nonwoven web with copper which comprises:
applying to the nonwoven web an aqueous copper formate solution; and irradiating the nonwoven web to which the copper formate solution has been applied with radiation from an excimer lamp having a wavelength effective to coat the substrate with copper:
in which the aqueous copper formate solution comprises water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator.
applying to the nonwoven web an aqueous copper formate solution; and irradiating the nonwoven web to which the copper formate solution has been applied with radiation from an excimer lamp having a wavelength effective to coat the substrate with copper:
in which the aqueous copper formate solution comprises water, copper formate, a surfactant, and an effective amount of a photo-redox facilitator.
11. The method of claim 10, in which the irradiation of the substrate is carried out in the absence of oxygen.
12. The method of claim 11, in which the wavelength of the radiation from the excimer lamp is 172 nanometers.
13. The method of claim 10, in which the substrate is a polyolefin nonwoven web.
14. The method of claim 10, in which the surfactant is a polysiloxane polyether.
15. The method of claim 10, in which the photo-redox facilitator is a protein or polypeptide.
16. The method of claim 10, in which the photo-redox facilitator is a collagen-derived polypeptide.
17. The method of claim 16, in which the collagen-derived polypeptide is a gelatin.
18. A method of coating a polyolefin nonwoven web with copper which comprises:
applying to the nonwoven web an aqueous copper formate solution; and irradiating the nonwoven web to which the copper formate solution has been applied in the absence of oxygen with radiation from an excimer lamp having a wavelength of 172 nanometers;
in which the aqueous copper formate solution comprises water, copper formate, a polysiloxane polyether surfactant. and an effective amount of a photo-redox facilitator which is a commercial edible gelatin.
applying to the nonwoven web an aqueous copper formate solution; and irradiating the nonwoven web to which the copper formate solution has been applied in the absence of oxygen with radiation from an excimer lamp having a wavelength of 172 nanometers;
in which the aqueous copper formate solution comprises water, copper formate, a polysiloxane polyether surfactant. and an effective amount of a photo-redox facilitator which is a commercial edible gelatin.
19. The method of claim 18, in which the polyolefin nonwoven web is a polypropylene nonwoven web.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US24191694A | 1994-05-11 | 1994-05-11 | |
| US241,916 | 1994-05-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2147522A1 true CA2147522A1 (en) | 1995-11-12 |
Family
ID=22912696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002147522A Abandoned CA2147522A1 (en) | 1994-05-11 | 1995-04-21 | Method of coating a substrate with copper |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2545095A (en) |
| CA (1) | CA2147522A1 (en) |
| WO (1) | WO1995031586A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB9717368D0 (en) * | 1997-08-18 | 1997-10-22 | Crowther Jonathan | Cold plasma metallization |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0300846B1 (en) * | 1987-06-30 | 1991-12-18 | Institut Français du Pétrole | Process for modifying the surface of a substrate by the formation of an alloy, use of the process, paticularly in the preparation of ferrous alloys, and catalysts and alloys obtained by the process |
| DE4035080A1 (en) * | 1990-11-05 | 1992-05-07 | Abb Patent Gmbh | METHOD AND DEVICE FOR PRODUCING PARTIAL METAL LAYERS |
| DE4113525C2 (en) * | 1991-04-25 | 1995-08-03 | Heraeus Noblelight Gmbh | Process for the metallization of surfaces of components and their use |
| US5176744A (en) * | 1991-08-09 | 1993-01-05 | Microelectronics Computer & Technology Corp. | Solution for direct copper writing |
-
1995
- 1995-04-21 CA CA002147522A patent/CA2147522A1/en not_active Abandoned
- 1995-05-09 WO PCT/US1995/005754 patent/WO1995031586A1/en active Application Filing
- 1995-05-09 AU AU25450/95A patent/AU2545095A/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| AU2545095A (en) | 1995-12-05 |
| WO1995031586A1 (en) | 1995-11-23 |
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