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
  • C23C18/18—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

Definitions

• the invention relates to a method for activating substrate surfaces for the purpose of chemical metallization.
• the polymer surface is changed so that caverns and vacuoles are formed.
• This is only possible with certain polymers, for example with 2-phase multicomponent grafts or copolymers, such as ABS polymers, impact-resistant polystyrene or 2-phase homopolymers, such as partially crystalline polypropylene.
• 2-phase multicomponent grafts or copolymers such as ABS polymers, impact-resistant polystyrene or 2-phase homopolymers, such as partially crystalline polypropylene.
• working with chromosulfuric acid or other oxidants is associated with a deterioration in the physical properties, such as notched impact strength, electrical surface resistance of the polymeric base material.
• the ionogenic palladium is reduced either in an acidic tin (II) chloride bath or by introducing tin (II) chloride into a strong hydrochloric acid palladium (II) chloride solution.
• the excess protective colloid must be removed from the substrate surface so that a reduction in the metal ions, e.g. Copper, nickel, gold and cobalt in the metallization bath is possible through the catalytic action of active palladium centers on the substrate surface.
• the metal ions e.g. Copper, nickel, gold and cobalt in the metallization bath
• the object of the present invention was to provide a new, gentle and procedurally simple method for activating substrate surfaces for the purpose of electroless metallization, with which even surfaces that are difficult to metallize can be provided with a well-adhering metal coating, preferably without prior etching.
• organometallic compounds of sub-groups 1 and 8 of the Periodic Table of the Elements the organic part of which has at least one further functional group in addition to the groups necessary for metal bonding.
• the invention therefore relates to a method for activating substrate surfaces for the purpose of electroless metallization, the surface to be metallized wetted with an organometallic compound of elements of the 1st and 8th subgroups of the Periodic Table of the Elements homogeneously distributed in a solvent, in particular an organic solvent, the solvent is removed and the organometallic compound adhering to the surface to be metallized is reduced, characterized in that the organic part of the organometallic compound has at least one further functional group in addition to the groups required for the metal bond.
• the other functional group achieves very good adhesive strength on the substrate surface, this adhesive strength being due to a chemical reaction with the substrate surface or to adsorption.
• Particularly suitable for a chemical anchoring the activator to the substrate surface are functional groups such as carboxylic acid groups, carboxylic acid halide, carboxylic anhydride, carbonate nests groups, carbonamido and Carbonimid phenomenon, aldehyde and ketone groups, ether groups, sulfonamide groups, sulfonic acid groups and sulfonate groups, Sulfonklarehalogenid phenomenon, sulfonic acid ester, halogen-containing heterocyclic groups such as Chlorotriazinyl, pyrazinyl, pyrimidinyl or quinoxalinyl groups, activated double bonds, such as in the case of vinylsulfonic acid or acrylic acid derivatives, amino groups, hydroxyl groups, isocyanate groups, olefin groups and acetylene groups and also mercapto groups and Epoxy groups, also higher-chain alkyl or alkenyl radicals from C 8 , in particular oleic, linoleic
• the adhesive strength can also be brought about by absorption of the organometallic activators on the substrate surface, the causes of the adsorption being e.g. Hydrogen bonds or van der Waalssche forces come into question.
• activators with, for example, additional carbonyl or sulfone groups are particularly favorable for metallizing objects based on polyamide or polyester.
• Functional groups such as carboxylic acid groups and carboxylic acid anhydride groups are particularly suitable for anchoring the activator to the substrate surface by adsorption.
• the groups of the organic part of the organometallic compound required for the metal bond are known per se. For example, they are C-C or C-N double and triple bonds and groups which can form a chelate complex, e.g. OH, SH, CO, CS or COOH groups.
• the organometallic compound can, for example, be dissolved or dispersed in the organic solvent, or it can also be a rubbing of the organometallic compounds with the solvent.
• organometallic compound contains ligands which allow chemical fixation on the substrate surface, activation from the aqueous phase may also be possible.
• polar, protic and aprotic solvents such as methylene chloride, chloroform, 1,1,1-trichloroethane, trichlorethylene, perchlorethylene, acetone, methyl ethyl ketone, butanol, ethylene glycol and tetrahydrofuran are suitable as organic solvents.
• Suitable substrates for the process according to the invention are e.g. Steels, titanium, glass, quartz, ceramics, carbon, paper, polyethylene, polypropylene, ABS plastics, epoxy resins, polyesters and textile fabrics, threads and fibers made of polyamide, polyester, polyolefins, polyacrylonitrile, polyvinyl halides, cotton and wool, and mixtures thereof or from copolymers of the monomers mentioned.
• the organic solvent is removed.
• Low boiling solvents are preferred by evaporation, e.g. removed in vacuum.
• other methods such as extraction with a solvent in which the oragnometallic compounds are insoluble, are appropriate.
• the surfaces pretreated in this way must then be activated by reduction.
• the reducing agents customary in electroplating such as hydrazine hydrate, formaldehyde, hypophosphite or boranes, can preferably be used for this purpose. Of course there are others too Reducing agent possible.
• the reduction is preferably carried out in aqueous solution. However, other solvents such as alcohols, ethers, hydrocarbons can also be used. Of course, suspensions or slurries of the reducing agents can also be used.
• the surfaces activated in this way can be used directly for electroless metallization. However, it may also be necessary to rinse the surfaces of the reducing agent residues.
• a very particularly preferred embodiment of the method according to the invention consists in that the reduction in the metallization bath is carried out immediately with the reducing agent of the electroless metallization.
• This version represents a simplification of the electroless metallization that has not been possible until now.
• This very simple embodiment only consists of the three work steps: immersing the substrate in the solution of the organic compound, evaporating the solvent and immersing the surfaces thus activated in the metallization bath (reduction and Metallization).
• This embodiment is particularly suitable for nickel baths containing amine borane or copper baths containing formalin.
• metallising baths with nickel salts, C obaltsalzen, copper salts, gold salts and silver salts, or their mixtures with one another or with iron salts.
• Such metallization baths are known in the electroless metallization art.
• the method according to the invention has the advantage of providing an adherent metal deposition by the subsequent electroless metallization, even without prior etching of the substrate surface.
• the activation and the Anquellun be g or the partial dissolution in a single operation carried out by reacting the organometallic compound used for the activation in such solvent systems consisting Banllust. Solvents exist for the polymer substrate to be metallized, .homogeneously distributed.
• the organometallic activators can be in the form of real solutions, emulsions or suspensions.
• the surface change caused by the "swelling adhesion nucleation" is noticeable through a change in the light separation, cloudiness, light permeability (in the case of intermingled foils and plates), change in layer thickness or in scanning electron microscope images in the form of cracks, caverns or vacuoles.
• the swelling agents suitable for the particular polymer substrate to be metallized must be determined on a case-by-case basis by means of appropriate preliminary tests.
• a swelling agent behaves optimally if it swells the surfaces of the substrates within reasonable times without completely dissolving the substrate or even negatively influencing its mechanical properties such as impact strength and without changing the organometallic activators.
• Suitable swelling agents are also in the abovementioned patent literature, for example the so-called solvents Solvents or their blends with precipitants, such as a "Polymer Handbook" J. Brandrup et al, New York, IV, 157-175, (1974) are described.
• Suitable swelling or solvents are lower and higher alcohols, aldehydes, ethers, ketones, halogenated hydrocarbons, simple or saturated hydrocarbons, organic acids, esters or their halogenated derivatives, liquid gases such as butane, propylene, 1,4-cis-butadiene.
• solvents and blends with other solvents such as gasoline, ligroin, toluene, n-hexane, etc. can of course also be used.
• solvents such as gasoline, ligroin, toluene, n-hexane, etc.
• such media can be provided with organic and / or inorganic additives.
• Anicnic emulsifiers such as Alkali salts of palmitic acid, stearic acid, oleic acid, salts of sulfonic acids, which are produced by sulfochlorination on the basis of paraffins containing 6-20 carbon atoms; non-ionic emulsifiers which can be prepared, for example, by ethoxylation of long-chain alcohols or phenols; cationic emulsifiers, e.g. Salts of long-chain, particularly unsaturated amines with 12 to 20 C atoms or quaternary ammonium compounds with long-chain olefins or paraffin esters;
• Protective colloids based on macromolecular compounds such as gelatin, pectins, alginates, methyl cellulose, ionic and neutral polyurethane dispersions or their oligomeric derivatives, polyvinyl alcohols, polyvinyl pyrrolidone, polymethyl vinyl acetate; finely divided water-soluble minerals such as alumina, diatomaceous earth, calcium phosphates; Alkali and alkaline earth salts CaCl 2 , MgS0 4 , K 3 P0 4 g ut suitable.
• macromolecular compounds such as gelatin, pectins, alginates, methyl cellulose, ionic and neutral polyurethane dispersions or their oligomeric derivatives, polyvinyl alcohols, polyvinyl pyrrolidone, polymethyl vinyl acetate; finely divided water-soluble minerals such as alumina, diatomaceous earth, calcium phosphates; Alkali and alkaline earth salts CaCl 2 , Mg
• the amount of the additives listed above can be varied, based on the medium at hand, from 0.01 to 20% by weight.
• anoragnic compounds such as C1 2 , HCl, H 2 0, HF, HJ, H 2 SO 4 , H 3 PO 4 , H 3 PO 3 , H 3 SO 3
• boric acids NaOH or KOH.
• Their amount can be varied from 0.1 to 30% by weight (based on the respective medium), the additions of anoragnic compounds in some cases being above or below.
• the surfaces of the substrates to be metallized are wetted with these media, the exposure time preferably being 1 second to 90 minutes.
• Methods such as immersing the substrate in the media or spraying, vapor deposition of substrate surfaces with the activation media are particularly suitable for this purpose.
• the adhesive seeding according to the invention can be carried out at a temperature of from -20 ° C. to 100 ° C., low temperatures being preferred for low-boiling solvents and chemically susceptible substrates, whereas chemically resistant substrates require higher temperatures. In exceptional cases, seeding can also be carried out at lower or higher temperatures from -20 ° C or 100 ° C. Temperatures of 0 ° C to 80 ° C are preferred.
• the solvent is removed as described above.
• an additional activation of the substrate surfaces in the activation medium which is a precipitant for the polymer material, can be carried out.
• Such precipitants are known and can be found in the "Polymer Handbook", IV, 241-267, which has already been given.
• a 10 x 10 cm square of a knitted fabric made of a polyester polymer (100% polyethylene terephthalate) is at room temperature for 10 seconds in an activation bath which consists of 0.4 g of 4-cyclohexene-1,2-dicarboxylic acid anhydride palladium (II) chloride and 1 1 CH 2 Cl 2 is prepared, immersed, dried at room temperature and then 10 minutes in an aqueous alkaline nickel plating bath which contains 3.5 g of dimethylamine borane, 30 g of nickel chloride and 10 g of citric acid in 1 1 and with conc. Ammonia solution is adjusted to pH 8.2, nickel-plated without current. After about 60 seconds, the surface begins to turn shiny metallic and after 10 minutes 12 g / m 2 had been deposited.
• an activation bath which consists of 0.4 g of 4-cyclohexene-1,2-dicarboxylic acid anhydride palladium (II) chloride and 1 1 CH 2 Cl 2 is prepared, immersed, dried at room
• a 150 x 100 mm injection-molded ABS plate (acrylonitrile-butadiene-styrene graft copolymer) is degreased in an aqueous 15% by weight sodium hydroxide solution, neutralized with distilled water, for 30 seconds in an activation solution of 0.8 g of 4-cyclohexene 1,2-dicarboxylic acid anhydride silver (I) nitrate immersed in 1 liter of methanol, dried at room temperature and then nickel-plated according to Example 1. The specimen is covered with a very fine nickel layer after only 60 seconds. After approx. 10 minutes the chemical nickel layer has an average thickness of approx. 0.20 ⁇ m.
• a 120 x 120 mm square of a cotton fabric is activated for 20 seconds according to Example 1 and then nickel-plated.
• a piece of shiny metallic material with a metal coating of about 11% by weight of nickel is obtained.
• a 35 x 100 mm rectangle made of a polyester film is activated for 20 seconds in accordance with Example 1 and nickel-plated for 7 minutes after the solvent has evaporated.
• a shiny metallic foil with a 0.15 ⁇ m thick nickel is obtained.
• a 40 x 60 mm rectangle of a roughened polycarbonate film with 10% by weight of polybutadiene is immersed in a solution of 0.5 g of 4-cyclohexene-1,2-dicarboxylic acid anhydride palladium dichloride in 1 liter of methanol, dried and then according to the example 1 nickel-plated.
• a 150 x 150 mm square of a cotton fabric is immersed in a solution of 0.5 g of isobutyl vinyl ether palladium dichloride in 1 liter of 1,1,1-trichloroethane for 30 seconds, dried at room temperature and then nickel-plated in a nickel bath according to Example 1 for 20 minutes.
• a 100 x 100 mm square of a glass fiber reinforced epoxy resin plate is sprayed with a solution of 0.6 g of isobutyl vinyl ether palladium dichloride in 1 1 1,1,1-trichloroethane, dried at room temperature and then nickel-plated in a chemical nickel bath according to Example 1.
• the surface of the plate begins to turn dark after only about 30 seconds, after 60 seconds it is covered with a fine layer of nickel and after about 10 minutes it has chemically deposited Nickel layer about 0.2 ⁇ m thick.
• a 150 x 50 mm rectangle of a polyethylene plastic part is immersed in an activation bath which is made up of 0.75 g of 9-octadecen-1-olpalladium dichloride and 1 1 1,1,1-trichloroethane, and then in a chemical nickel bath according to Example 1 nickel plated.
• a shiny metallic plastic part is obtained, which is switched in a galvanic semi-gloss nickel bath as the cathode at 50 ° C. and 1 ampere in 30 minutes to a thickness of approximately 8.1 ⁇ m.
• Isobutyl vinyl ether palladium dichloride is obtained in an analogous manner from the acetonitrile palladium dichloride and isobutyl vinyl ether, melting point: 57-60 ° C.
• a plastic plate made of polyamide 6/6 with the dimensions 15 x 10 cm and 3 mm thickness is degreased in 25% sodium hydroxide solution at room temperature.
• the plastic plate is then immersed for one minute in an adhesive seeding solution which contains 67.5% by volume of methanol, 22.5% by volume of methylene chloride, 10% of chloral hydrate and 0.3 g / 1 of butadiene palladium chloride.
• the substrate activated in this way is dried and then immersed in an electroless nickel plating bath which contains 25 g / 1 nickel chloride, 3 g / l dimethylamine borane, 10 g / 1 citric acid and was adjusted to pH 7.9 with ammonia. After 20 minutes, a uniform, shiny nickel layer is deposited.
• the adhesive strength determined by the peel force according to DIN 53494, is 7.7 N / 2.5 cm.
• a plastic plate according to Example 9 is degreased at room temperature in 25% sodium hydroxide solution. It is then immersed for 5 minutes in an adhesive seeding solution which consists of 72.5% by volume of dimethylformamide, 22.5% by volume of water, 5% by volume of 37% aqueous HC1 and 0.3 g / 1 of butadiene palladium dichloride . The sample is then nickel-plated in a metallization bath according to Example 9 for 60 minutes. A uniform, matt nickel surface is obtained, in which the pull-off force increases DIN 53494 can no longer be determined because the adhesive strength of the galvanically reinforced nickel layer is higher than the tensile strength of the metal film.
• a polyamide 6/6 plate according to Example 9 is degreased at room temperature with 25% sodium hydroxide solution. The plate is then immersed for 10 minutes in a solution which contains 80% by volume of methanol and 20% by volume of methylene chloride, 40 g / 1 calcium chloride and 0.3 g / 1 butadiene palladium chloride. The plate is then dried with a cloth and then nickel-plated in a metallization bath according to Example 9 for 20 minutes. A uniform, shiny nickel layer is obtained. Adhesive strength after galvanic reinforcement cannot be determined on this sample either, since the required pull-off force is higher than the tensile strength of the metal layer.
• a test plate 10 x 15 cm, 3 mm layer thickness, one with 10% mineral-reinforced polyamide 6 plastic is degreased at room temperature with 25% sodium hydroxide solution.
• the plate is then immersed for 1 hour in a solution containing per liter of methanol, 100 g of calcium chloride and 0.3 g of bis (alyl palladium) dichloride.
• the plate is washed with methanol, dried and on finally immersed in an electroless nickel plating bath according to Example 9. After 20 minutes, an even, matt nickel layer has deposited. After galvanic reinforcement, the pull-off force of the metal layer is higher than the tensile strength of the metal layer.
• a polymer plate made of polyamide 6 with 30% by weight of glass fibers is degreased in 20% sodium hydroxide solution at room temperature (RT). Then it is immersed for 8 minutes in an adhesive seeding solution consisting of 40% by weight hydrochloric acid (37% pure), 60% by weight methanol and 0.9 g / l 4-cyclohexene-1,2-dicarboxylic anhydride palladium (II) chloride exists.
• the sample is then nickel-plated for 20 minutes in a metallization bath which contains 30 g / 1 nickel sulfate, 3.8 g / l dimethylaminobrorane, 10 g / l citric acid and is adjusted to pH 7.6 with concentrated aqueous ammonia solution.
• the adhesive strength of the metal pad which is determined by the peel force according to DIN 53494, is ⁇ 6N / 2.5 cm.
• a polymer plate made of polyamide 6 with 35 wt .-% butadiene graft polymer is at room temperature in 15% sodium. alkali degreased. Then it is 10 minutes in a bath which is made up of 90 g HC1 (travels 37%), 410 g ethylene glycol and 0.5 g 4-cyclohexene-1,2-dicarboxylic acid anhydride palladium (II) chloride, acti fourth and then metallized in a metallization bath according to Example 13 over the course of 20 minutes. After galvanic reinforcement, the pull-off force of the metal layer is higher than the tensile strength of the metal layer.
• a test plate 10 x 10 cm, 3 mm layer thickness, of an ABS (acrylonitrile-butadiene-styrene) plastic is degreased at room temperature with 22% NaOH solution.
• the plate is then immersed for 10 minutes in a solution containing 700 ml of methanol, 100 ml of acetoacetic ester, 50 ml of DMF (dimethylformamide) and 0.9 ml of 4-cyclohexene-1,2-dicarboxylic acid anhydride palladium (II) chloride.
• the plate is washed with methanol, dried and then neutralized in an electroless nickel plating bath according to Example 13. After 25 minutes, an even, matt Ni coating has deposited.
• the adhesive strength, determined by the peel force according to DIN 53494, is 5N / 2.5 cm.

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• 1981
  • 1981-12-05 DE DE19813148280 patent/DE3148280A1/de not_active Withdrawn
• 1982
  • 1982-11-20 DE DE8282110736T patent/DE3275105D1/de not_active Expired
  • 1982-11-20 EP EP82110736A patent/EP0081129B1/fr not_active Expired
  • 1982-12-06 JP JP57212820A patent/JPS58104170A/ja active Granted
• 1987
  • 1987-01-28 US US07/007,706 patent/US4764401A/en not_active Expired - Fee Related

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