Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D17/00—Constructional parts, or assemblies thereof, of cells for electrolytic coating
  • C25D17/06—Suspending or supporting devices for articles to be coated
  • C25D17/08—Supporting racks, i.e. not for suspending
• • 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
  • C23C18/16—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 by reduction or substitution, e.g. electroless plating
  • C23C18/1601—Process or apparatus
  • C23C18/1619—Apparatus for electroless plating
  • C23C18/1621—Protection of inner surfaces of the apparatus
  • C23C18/1625—Protection of inner surfaces of the apparatus through chemical processes
• • 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
  • C23C18/16—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 by reduction or substitution, e.g. electroless plating
  • C23C18/1601—Process or apparatus
  • C23C18/1619—Apparatus for electroless plating
  • C23C18/1628—Specific elements or parts of the apparatus
  • C23C18/163—Supporting devices for articles to be coated
• • 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
  • C23C18/16—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 by reduction or substitution, e.g. electroless plating
  • C23C18/1601—Process or apparatus
  • C23C18/1633—Process of electroless plating
  • C23C18/1646—Characteristics of the product obtained
  • C23C18/165—Multilayered product
  • C23C18/1653—Two or more layers with at least one layer obtained by electroless plating and one layer obtained by electroplating
• • 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
  • C23C18/16—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 by reduction or substitution, e.g. electroless plating
  • C23C18/18—Pretreatment of the material to be coated
  • C23C18/20—Pretreatment of the material to be coated of organic surfaces, e.g. resins
  • C23C18/2006—Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30
  • C23C18/2046—Pretreatment of the material to be coated of organic surfaces, e.g. resins by other methods than those of C23C18/22 - C23C18/30 by chemical pretreatment
  • C23C18/2073—Multistep pretreatment
  • C23C18/2086—Multistep pretreatment with use of organic or inorganic compounds other than metals, first
• • 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
  • C23C18/16—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 by reduction or substitution, e.g. electroless plating
  • C23C18/18—Pretreatment of the material to be coated
  • C23C18/20—Pretreatment of the material to be coated of organic surfaces, e.g. resins
  • C23C18/22—Roughening, e.g. by etching
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/10—Electroplating with more than one layer of the same or of different metals
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/60—Electroplating characterised by the structure or texture of the layers
  • C25D5/625—Discontinuous layers, e.g. microcracked layers
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
  • C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
  • C25D5/627—Electroplating characterised by the visual appearance of the layers, e.g. colour, brightness or mat appearance
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal
  • Y10T428/31692—Next to addition polymer from unsaturated monomers
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31855—Of addition polymer from unsaturated monomers
  • Y10T428/31935—Ester, halide or nitrile of addition polymer

Definitions

• ABSTRACT No rerack process for the metal plating of electrically nonconductive articles or objects on vinyl plastisolcoated plating racks, involving contacting the rack prior to 0 RERACK METAL PLATING 0F rzllctkigg threreqn t lzlel HOIICOIIISUICFVC arti gles deitiniq t; Ilie ELECTRICALLY NONCONDUCTIVE ARTICLES e a a y v dimethylformamide, or N-methyl-Z-pyrrohdone, or a mixture 23 Claims No Drawmgs thereof, for a time sufficient to render the rack substantially 52] US.
• This invention relates to metal plating and more particularly to a process forthe metal plating of an electrically nonconductive articles or object on a plastisol-coated rack; usually a vinyl plastisol-coated rack, which eliminates any substantial deposition of metal on the rack.
• This invention' also relates toa no rerack process for metal plating nonconductive articles or objects wherein the'articles are retained on the same rack during the entirety of the process, and without the requirement of reracking the articles or objects on clean racks after the electroless metal plating and before the electroplating.
• Additional curing of the plastisol-coated racksto prevent metal plating thereof during the electroless metal plating may be effective for a few days after which the racks again are metal plated during the electroless plating. Further the danger of overcurin'g is attendant with the additional curing, with overcuring destroying desired physical properties of the plastisol of the rack coating.
• a primary object of this invention is to provide a new and improved process for metal plating plastic articles or objects on plastisol coated racks otherwise susceptible to electroless metal plating deposition thereon, which eliminates the necessity of reracking the articles on clean racks after the electroless metal plating and prior to the electroplating.
• a electrically nonconductive article, object or part for instance plastic articles, objects or parts
• a plastisol-coated plating rack usually a vinyl plastisol-coated rack without any substantial deposition of metal on the rack during the electroless plating step.
• This elimination of any substantial electroless deposition of metal on the rack which is otherwise susceptible to electroless plating deposition of metal thereon is accomplished in accordance with the invention by contacting the plastisol coated rack, prior to racking the electrically nonconductive article or articles destined to be metal plated thereon, with a liquid material such as a lower alkyl formamide, 'e.g.
• the compound can be in liquid solution, for instance an aqueous solution of the compound, or the anhydrous compound per se.
• the contacting of the plating rack with such treatment liquid is effected for a time sufficient to render the plastisol-coated rack substantially nonsusceptible to the electroless deposition of metal thereon during a subsequent chemical reduction metal plating step.
• the nonconductive article or articles or be plated are then racked onthe thustreated' rack followed'by activating the nonconductive article or articles and electrolessly metal plating the racked article by contacting the article with a chemical reduction metal plating solution until a metalplating of the desired thickness is deposited on'the-article-surface, or until the article surface is rendered electrically conductive;
• This electroless metal plating 0 of the racked article'or articles occurs without any substantial metal platingof the rack.
• the thus-plated article or articles still on thesame rack can'then be-and usually are electroplated, to deposit one or more metal electroplate layers overthe electroless metal plate.
• coating is over the structural members of the rack which are usually metallic structural members.
• Th'e'contactin'gof the plating rack with the'lower alkyl formamide or N-methyl-2- -pyrrolidone is usually by immersing the rackin a liquid bath or pool of the-anhydrous compound or a suitables'oiution thereof, usually anaqueous solution of the compound.
• a suitables'oiution thereof usually anaqueous solution of the compound.
• Such contacting may be effected by spraying, pouring or in any other'suitable manner. A contact.
• the present invention is primarily intended for use on plastisol-coated racks in an intermediate stageof their life and which have developed through use a susceptibility to plating metal thereon during the electroless plating step.
• Thisinvention may not be advantageousfor use on new plastisol-coated racks or on old racks inasmuch as such racks may not be susceptible to metal plating deposition during the electroless plating step.
• it is desired to use the present invention on new and old racks this is considered within the inventions scope.
• the contacting of the plastisol-coated rack with the liquid lower alkyl formamide and/or the liquid N-methyI-Z-pyrrolidone can be carried out at room temperature, except when such compound is a solid in which event the solid is preheated intoliquid form.
• the" liquified solid or liquid mixture containing same may be heated gently to maintain it in liquid phase.
• the compounds can be employed in the liquid mixture in any desired suitable ratio. Whether such compounds are utilized in the mixture in anhydrous or substantially anhydrous state or in aqueous solution will be dependent on the particular lower alkyl formamide utilized.
• the preferred N, N-dimethylformamide and N-methyl-Z-pyrrolidone are utilizable in the mixture in anhydrous or substantially anhydrous forms, or inaqueous formamide, both the N, N-diethyi formamide and N-methyl-Z-pyrrolidone are utilized in anhydrous or substantially anhydrous form.
• the lower alkyl formamide of this invention can usually be presented by the following formula:
• the lower alkyl formamide can be utilized in anhydrous state or when in solution in a suitable liquid solvent, usually water.
• Aqueous solutions of N, N-dimethylformamide of about 58-95 weight percent dimethylformamide concentration are effective in inhibiting electroless metal plating of vinyl plastisoI-coated racks.
• N, N-diethylformamide is effective in anhydrous or substantially anhydrous condition for inhibiting electroless metal plating of vinyl plastisoI-coated racks.
• the N-methyl-Z-pyrrolidone is also utilizable in the present invention in anhydrous or substantially anhydrous state or when in solution in a suitable liquid solvent, usually water.
• aqueous solutions of N-methyl-2-pyrrolidone are effective for inhibiting electroless metal plating of vinyl plastisoI-coated plating racks at concentrations of such compound of about 80 percent by weight and higher up to and including anhydrous state of the N-methyl-2-pyrrolidone.
• nonconductive articles or-parts to be plated for instanceplastic articles or parts, e.g. articles or parts of ABS copolymer, are racked on the'thus-treated rack.- The'surfaces of the racked articles, if not already cleaned, arecleaned by immersion in a conventional nonsilicated alkaline cleaner solution. When the articles or parts have hydro'phobic'surfaces, which is usually the situation with plastic articles or parts, the surfaces are then converted from a hydrophobic state to a hydrophilic state wherein the surfaces are readily receptive to the aqueous solutions of the chemical reduction metal plating process or cycle.
• the conversion of the hydrophobic plastic surfaces to hydrophilic surfaces is preferably effected by contacting the hydrophobic surface with, usually by immersing such surfaces of the racked articles in, a conditioning or etchant solution comprising an aqueous acid solution containing concentrated sulfuric-acid (typically of 98 percent H SO,concentration) and chromic acid (Cr 0 and which may also contain phosphate ions.
• a conditioning or etchant solution comprising an aqueous acid solution containing concentrated sulfuric-acid (typically of 98 percent H SO,concentration) and chromic acid (Cr 0 and which may also contain phosphate ions.
• the conversion of the hydrophobic article surfaces-to hydrophilic surfaces can also be effected mechanically by rougheningthe hydrophobic surface, for instance by sanding, sand blasting'or abrading'the hydrophobic surface or surfaces.
• the conditioning solution is an aqueous solution of the following compositron:
• hydrophilic nonconductive or nonmetallic surfaces of the racked articles are then activated in conventional manner, by contacting the hydrophilic surfaces with, usually by immersing the surfaces in, a sensitizer solution,usually a'stannous chloride-containing aqueous acid solution containing, in addition to stannous chloride, HCl and water, followed by water rinsing.
• a sensitizer solution usually a'stannous chloride-containing aqueous acid solution containing, in addition to stannous chloride, HCl and water, followed by water rinsing.
• a typical sensitizer solution is the following:
• the HCI was the analytic reagent grade.
• the sensitizer is utilized at room temperature for 1-3 minutes.
• the sensitized surfaces of the articles still on the same rack are then contacted with an activator solution, usually by immersing the surfaces in the activator solution.
• the activator solution is usually a palladous chloride-containing aqueous acid solution containing, in addition to palladous chloride, HCI and water.
• Other noble metal ions e.g. platinum or gold ions, are utilizable in the activator solution instead of the ionic palladium.
• a typical activator solution has the following composition:
• the HCl was the analytic reagent grade.
• the above activator solution is used at room temperature, with one-half-lminute immersion times. After activating is completed, the surface of the racked articles are then water rinsed.
• the sensitizing step can be eliminated by combining the stannous chloride of the sensitizer and palladous chloride in one composition to form a colloidal catalyst solution containing colloidal palladium metal particles dispersed in a liquid medium as disclosed in U.S. Pat. No. 3,0l L920
• a colloidal catalyst solution containing colloidal palladium metal particles dispersed in a liquid medium as disclosed in U.S. Pat. No. 3,0l L920
• the racked plastic articles are immersed in or otherwise treated with the colloidal catalyst solution until their surfaces are activated for the subsequent electroless metal plating.
• the racked activated articles are then 'electrolessly metal plated by contacting the article surfac'es'with', usually by immersing the articlesin a chemical reduction metal plating.
• exemplary of the chemical reduction metalplating. solutions are chemical reduction copper plating solutionsand chemical reduction'nickel plating,
• Ve'rsene T is a trademarked material containing- EDTAand triethanolamine.
• the articles stillon the sa'r'nerack are then electroplated with; forexaniple', copper in the usual man'ner'A typical'electroplatihgbath for this purpose is an acid sulfate aqueous bath containing 20'0-300' ./1. of cu so,-5-H,0' and l5-40-g1/l. of free H-,so-, (66 Be).
• one or more final electroplates which may be decorative, are usually applied over the first-mentioned metal electroplate.
• These final electrop'lates areordinarily thin layers and may be a layer of brightnickel followedby a layer of chromium thereover, or a layer of duplex nickel with a layer if microcracked chromium thereover.
• the electrically nonco'nducti've articles or parts metal plated'herein include, for example, plastic knobs for window crank handles of automobiles and garnish or decorative plastic moldings for automobiles.
• the plastic includes, for example ABS copolymer, i.e. acrylonitrile-butadiene-styrene co'polymer, and other polymers or plastics, e.g. polypropylene, polystyrene and polycarbonate.
• N, N-dimethylfo'rmarnide was found to inhibit electroless metal plating of the vinyl pla'stisol-coated plating rack after immersion of the rack in aqueous solutions of the N, N-dimethylformamide of about 5895 weight percent N, N-dimethylformamide concentration.
• Substantially anhydrous N, N-diethylformamide was effective in inhibiting electroless metal plating of the vinyl plastisol-coated rack, but an aqueous solution of percent by volume N, N-diethylformamide concentration was not effective in inhibiting the rack plating.
• Aqueous solutions of N-methyl-Z-pyrrolidone of 80 volume percent and higher N-methyl-2-pyrrolidone concentration were found to be effective in inhibiting electroless metal plating of the vinyl plastisol-coated racks.
• Anhydrous N-methyl-2- pyrrolidone was also found to be effective in inhibiting electroless metal plating of such racks.
• 2-pyrrolidone was not effective in anhydrous state or in aqueous solution of 95 volume percent 2-pyrrolidone concentration and actually enhanced electroless metal plating of the racks.
• Formamide, acetamide and methyl ethyl ketone were found not effective for inhibiting electroless metal plating of vinyl plastisol-coated racks. Tetrahydrofuran was also found to be unsatisfactory for inhibiting such rack plating.
• the tests also revealed that the N, N-dimethylformamide in aqueous solutions of the N, N-dimethylformamide concentration set forth immediately supra, the substantially anhydrous N, N-diethylformamide, the N-methyl-Z-pyrrolidone in aqueous solutions of the N-methyl-Z-pyrrolidone concentration set forth immediately supra, and anhydrous N-methyl-2-pyrrolidone, were effective in inhibiting electroless metal plating of the vinyl plastisol-coated racks when the activating was effected by immersing the racked plastic articles in a colloidal catalyst solution containing colloidal palladium metal particles dispersed in water.
• the racks which were in an intermediate stage of life and susceptible to electroless metal plating were metal plated during the electroless plating step, when the activating waseffected using the colloidal catalyst solution containing the colloidal palladium metal particles dispersed in water.
• a process for the metal plating of electrically nonconductive articles on plastisol-coated plating racks which comprises:
• N,N-dimethylformamide is an aqueous solution of about 58-95 weight percent N ,N -dimethylformamide concentration.
• N-methyl-Z-pyrrolidone is in an aqueous solution of at least about weight percent N-methyl-Z-pyrrolidone concentration.
• a no rerack process for the metal plating of plastic articles on vinyl plastisol-coated racks which comprises:
• step (e) the electroless metal plating of step (e) and hence the electroplating of step (f) occurring without any substantial metal plating of the rack.
• the lower alkyl formamide is of the formula wherein the Rs represent a l-4C alkyl group or a hydrogen atom with at least one R being a l-4C alkyl group.
• N,N-dimethylformamide is in an aqueous solution of about 58-95 weight N,N- dimethylformamide concentration.
• N-methyl-Z-pyrrolidone is in an aqueous solution of at least about 80 weight percent N-methyl-Z-pyrrolidone concentration.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• General Chemical & Material Sciences (AREA)
• Mechanical Engineering (AREA)
• Electrochemistry (AREA)
• Inorganic Chemistry (AREA)
• Chemically Coating (AREA)
• Electroplating Methods And Accessories (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=21753548

Family Applications (1)

Country Status (3)

Cited By (11)

Citations (1)

• 1970
  • 1970-02-17 US US12134A patent/US3619243A/en not_active Expired - Lifetime
• 1971
  • 1971-01-27 CA CA103,779A patent/CA943824A/en not_active Expired
  • 1971-02-15 JP JP674571A patent/JPS5522551B1/ja active Pending

Patent Citations (1)

Also Published As

Similar Documents