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
  • C23C18/16—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
  • C23C18/22—Roughening, e.g. by etching
  • C23C18/24—Roughening, e.g. by etching using acid aqueous solutions
• • 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
  • C23C18/28—Sensitising or activating
  • C23C18/285—Sensitising or activating with tin based compound or composition
• • 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
  • C23C18/28—Sensitising or activating
  • C23C18/30—Activating or accelerating or sensitising with palladium or other noble metal
• • 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
  • C25D5/12—Electroplating with more than one layer of the same or of different metals at least one layer being of nickel or chromium

Definitions

• the invention concerns a process for the direct metallizing of the surface of a plastic object, using these steps: roughening the surface of the plastic object by pickling; activating the surface with the aid of a colloidal or ionogen aqueous solution of a first precious metal, which colloidal or ionogenic solution also contains a second base metal, whereby an activating coat containing the first precious and second base metal is formed on the surface; and providing electron conductivity on the activating coat with the aid of a preferably alkaline treatment solution, with which the second base metal is at least partially dissolved out of the activating coat and an electron-conductive substance is adsorbed in the activation coat; whereby the electron-conductive activation layer is then metallized.
• the invention thus concerns a process for the direct galvanic metallizing of a plastic surface.
• Plastics metallized in this way are used for decorative purposes, for example in the health sector or in automobile manufacturing.
• Metallizing of plastics is also performed as part of the coating of electronic components for the purpose of electromagnetic shielding.
• different plastics can be galvanically metallized.
• the surface of plastic such as acrylonitrile-butadiene-styrene (ABS) and, where necessary, blends of ABS and polycarbonates (PC) can be metallized for decorative purposes.
• ABS acrylonitrile-butadiene-styrene
• PC polycarbonates
• chrome (VI) is reduced to chrome (III) as part of the process.
• activation in a colloidal acid solution of palladium which contains additional tin compounds.
• sufficient electron conductivity is produced for the subsequent metallization.
• a tin/copper exchange is performed.
• the treatment solution used for this contains copper ions, which are bound by a biologically degradable complex forming substance.
• the tin/copper exchange is based on a charge exchange, in which tin (II) is oxidized by the copper ions to tin (IV) and whereby the copper ions themselves are reduced to metallic copper and deposited on palladium clusters on the surface of the plastic.
• tin (II) is oxidized by the copper ions to tin (IV) and whereby the copper ions themselves are reduced to metallic copper and deposited on palladium clusters on the surface of the plastic.
• the palladium clusters which formed during activation with the colloidal solution become electron-conductive.
• This known process is characterized by a number of disadvantages. First, only limited quantities of palladium/tin can be applied to the roughened plastic surface with this process. There are corresponding limits to the metallization of these plastic surfaces. In addition, only ABS or ABS blends can normally be metallized with some degree of acceptability with this process.
• ABS blends in particular leaves much to be desired.
• the metallization can often not be performed with any degree of reproducibility, and frequently certain areas on the surface of the plastic object to be metallized are not covered with an adequate metal coat. If plastic objects composed of different plastics are to be metallized with the known process, only ABS or ABS blends are metallized as a rule.
• the invention is based on the technical problem of describing a process of the type named at the beginning, with which different plastics can be metallized safely and reproducibly, and in which the plastics are given a metal coat which meets all requirements.
• the invention defines a process as described above which is characterized by the repetition at least once of the sequence of steps
• step 1.2 activation of the surface according to step 1.2) and making the activation layer electron-conductive according to step 1.3)" before the metallizing of the electron- conductive activation coat. It is part of the invention that steps 1.2) and 1.3) are repeated several times before the metallizing of the electron-conductive activation coat.
• the invention is based on the finding that metallizing of plastic objects that is especially safe and effective can be achieved if the theory according to patent claim 1 can be realized.
• the volume of adsorbed precious metal/base metal on the surface of the plastic can be increased substantially - surprisingly as part of the activation.
• metal coats with outstanding quality can be applied to the plastic objects as a result.
• a variety of different plastics can be metallized effectively and safely with the process under the invention.
• ABS ABS blends, particularly ABS/PC blends, can be metallized reproducibly and the resulting metal coats meet all requirements.
• large plastic objects for example large ABS/PC parts such as automotive radiator grills, can be metallized without difficulty.
• the surfaces of plastic objects consisting of a number of different plastics can be metallized without difficulty and, if desired, completely.
• roughening the surface of the plastic object is carried out by pickling with chromic sulfuric acid.
• chromic sulfuric acid For practical terms, a solution containing 400 g/l chromic acid and 400 g/l sulfuric acid is used.
• Pickling can be carried out solely with chromic acid. It is part of the invention that after pickling with chromic sulfuric acid or chromic acid, chrome (VI) is removed as completely as possible from the surface of the roughened or etched surface. Preferably, intensive rinsing is performed first after the roughening of the surface. In accordance with a preferred type of implementation of the invention, chrome (VI) is reduced to chrome (III) after the pickling with chromic sulfuric acid or chromic acid.
• this chrome reduction takes place after the aforementioned rinsing.
• Potassium bisulfide or potassium hyposulfite can be used, for example, for the reduction of chrome (VI) to chrome (III).
• at least one rinsing takes places following the chrome reduction.
• roughening of the plastic surface is carried out by pickling with a permanganate solution.
• the roughening is achieved by plasma pickling.
• the surface of the plastic object is pretreated with acid by immersion before the activation of the surface in accordance with step 1.2).
• the acid is preferably a mineral acid, hydrochloric acid is the most preferred.
• the pretreatment is performed by immersion in a concentrate of hydrochloric acid, preferably 30% by volume hydrochloric acid.
• the steps "pretreatment by immersion in an acid, activation of the surface in accordance with step 1.2) and providing electron conductivity in accordance with step 1.3)" are repeated at least once before metallizing the electron-conducting activation coat.
• the steps "immersion -- activation - providing electron conductivity” are performed in succession and then this sequence of steps "immersion - activation - providing electron conductivity” is repeated at least once.
• this sequence of steps can be repeated several times, i.e. more than twice, before metallizing the electron-conducting activation coat.
• the "immersion - activation - providing electron conductivity” steps can then be performed and subsequently only the sequence "activation - providing electron conductivity” is repeated at least once.
• two different metallic elements are used in the colloidal or ionogenic aqueous solution to the activate the surface, namely a precious metal and a second base metal that is different from the first metal.
• the precious metal is palladium and the base metal is tin.
• a tin (II) stabilized palladium colloidal solution is used for activation. Palladium and tin are adsorbed from this solution on the pretreated surface of the plastic object.
• a hydrochloric acid palladium-tin solution is used to activate the surface.
• the activation coat consists of a palladium-tin coating.
• an acidic, most preferably a hydrochloric acid, colloidal aqueous solution is used in the inventive process. It is within the scope of the invention that rinsing is performed after the activation of the surface.
• providing electron conductivity on the activation coat means sufficient electron conductivity of the activation coat for the subsequent metallizing. That, according to step 1.3), the second base metal is at least partially dissolved out of the activation coat and an electron-conductive substance is adsorbed in the activation coat, means, according to one version of the invention, that the second base metal, for example tin, is partially or completely dissolved out of the activation coat and replaced with an electron-conducting substance, for example another metal. That an electron-conducting substance is adsorbed in the activation coat also means, according to another version of the invention, that the second base metal is dissolved at least partially out of the activation coat and an electron- conducting substance is formed in the activation coat.
• a reaction with the second base metal takes place and an electron-conducting substance, respectively an electron-conducting compound, is formed in the activation coat.
• an electron-conducting substance respectively an electron-conducting compound
• the second base metal is replace with a third metal to establish the electron conductivity of the activation coat. It is within the scope of the invention that the second base metal in the activation coat has an oxidation level >0.
• the third metal which, preferably in an elementary metallic form, ensures the electron conductivity of the activation coat.
• the second base metal is replaced by a third metal, which is precious compared with the second one.
• the third metal is preferably copper.
• the treatment solution contains copper ions, which are preferably bonded by a complex forming substance.
• the base metal bonded to the plastic surface preferably tin, is exchanged for copper in the treatment solution.
• tin (II) ions are oxidized by the copper ions to tin (IV).
• the copper ions themselves are reduced to metallic copper and bonded to the plastic surface.
• the electron-conducting substance which partially or completely replaces the second base metal from the activation coat, does have to be a metal as part of the invention, but not absolutely.
• a preferably alkaline treatment solution of electron conducting compounds of elements from the 6th and/or 7th main group of the periodic system, or mixtures of them is used in another type of implementation of the invention. It is within the scope of the invention that, in this version, the electron conducting substance in the activation coat is formed by chemical reaction, for example with a second base metal.
• direct metallizing of the surface of the plastic object can take place. It is within the scope of the invention that direct electrolytic metallizing is carried out.
• a copper coat is applied to the electron conducting activation coat by means of electrolytic metallizing.
• a nickel coat is applied to the electron conducting activation coat by means of electrolytic metallizing.
• other metal coats for example a chrome coat, can be applied to the electron conducting activation coat as part of metallizing. It is evident that not just one metal coat can be applied, but a number of metal coats can be applied in succession.
• Fig. 1 illustrates the time-dependent adsorption of palladium/tin on the surface of a plastic object using the known state-of-the-art process, wherein the x-axis represents time expressed in minutes, and the y-axis represents the palladium/tin adsorption expressed in mg/dm 2 ;
• Fig. 2 which illustrates the time-dependent adsorption of palladium/tin on the surface of a plastic object using the process of the invention, wherein the x-axis represents time expressed in minutes, and the y-axis represents the palladium/tin adsorption expressed in mg/dm 2 .
• Fig. 1 shows the adsorption of palladium/tin that is achieved by using the known process explained at the beginning on the surface of a plastic object.
• Curve 1 shows the adsorption on the surface of an ABS plastic object
• Curve 2 shows the adsorption on the surface of an ABS/PC plastic object.
• the plastic objects were first pickled in a solution of 400 g/l of chromic acid and 400 g/l of sulfuric acid, and then a reduction of chrome (VI) to chrome (III) was carried out. Then came a pre- immersion in a 300 ml/l concentration of hydrochloric acid. Activation followed afterwards in a tin (II) stabilized palladium colloidal solution. It can be seen in Fig.
• Fig. 2 shows the adsorption of palladium/tin on the surface of plastic objects using the process from the invention.
• Curve 3 shows the adsorption of palladium/tin on an object made of ABS
• Curve 4 shows the adsorption on an object made of ABS/PC.

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• 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)
• Chemically Coating (AREA)
• Electroplating Methods And Accessories (AREA)
• Treatments Of Macromolecular Shaped Articles (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

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Citations (1)

• 1998
  • 1998-12-14 DE DE19857290A patent/DE19857290C2/de not_active Expired - Fee Related
• 1999
  • 1999-12-14 CA CA002355260A patent/CA2355260A1/en not_active Abandoned
  • 1999-12-14 JP JP2000588433A patent/JP2002532630A/ja active Pending
  • 1999-12-14 CN CN99814415A patent/CN1330734A/zh active Pending
  • 1999-12-14 BR BR9916170-2A patent/BR9916170A/pt not_active Application Discontinuation
  • 1999-12-14 EP EP99966383A patent/EP1157149A4/en not_active Withdrawn
  • 1999-12-14 WO PCT/US1999/030124 patent/WO2000036189A1/en not_active Ceased

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