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
  • C23C18/2006—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
  • C23C18/2053—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 only one step pretreatment
  • C23C18/206—Use of metal other than noble metals and tin, e.g. activation, sensitisation with metals
• • 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
  • C23C18/1635—Composition of the substrate
  • C23C18/1639—Substrates other than metallic, e.g. inorganic or organic or non-conductive
  • C23C18/1641—Organic substrates, e.g. resin, plastic
• • 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
  • C23C18/208—Multistep pretreatment with use of metal 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
  • C23C18/2006—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
  • 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
  • C23C18/30—Activating or accelerating or sensitising with palladium or other noble metal

Definitions

• the invention relates to a process for the adherent metallizing of non-conductors, especially synthetic resins and rubber, by the non-electrolytic deposition of an electrically conductive metal layer from a predominantly aqueous metal salt solution in the presence of metals catalysing the deposit of the metals which is easy to carry out. Further metal layers can, if desired, be deposited galvanically over such electrically conductive layer for technical or decorative purposes.
• metal layers can be appled to nonconductors by non-electrolytic methods by chemical deposition or by deposition by vaporization.
• the non-electrolytic chemical deposition of metals on non-conducting materials depends upon the reduction of a metal 'salt solution which wets the object to be metallized with a reducing agent to a metal or to a metal phosphide or boride when hypophosphites, boranates or borazanes are used.
• Metal salt solutions are used as metallizing baths in which the metal is bound in a complex.
• a complex is formed, that is, a compound containing amino, hydroxyl and/or carboxyl groups is added to an aqueous solution of a metal salt to form the corresponding metal complex salt.
• the concentration of free metal ions is considerably reduced in the solution of the complex salt so that when the reducing agent is added to the hath no metal deposit occurs either on the object to be metallized or in the solution.
• Such baths therefore are relatively stable and are suited for longer periods of use.
• This stability of the baths which can still be increased by the use of stabilizing agents, however, is undesired at the surface of the object to be metallized so that the surface of such object must be activated in order that when such object is dipped into the metallizing bath a regulated deposit of metal can take place thereon.
• Such activation can be effected by pretreatment of the object to be metallized which is essentially carried out in two steps.
• the object is first sensitized with a solution which contains a reducing agent, for instance, tin II chloride, and then activated by treatment with a metal salt solution, preferably, a noble metal salt solution (silver nitrate, palladium II chloride) from which nuclei of the corresponding metal are deposited by reduction.
• a metal salt solution preferably, a noble metal salt solution (silver nitrate, palladium II chloride) from which nuclei of the corresponding metal are deposited by reduction.
• Such metal nuclei in view of the catalysing effect upon the metal deposit effected when the object is subsequently introduced into the actual metallizing bath causes a uniform metallizing of the object so that the object can then be coated with a metal layer for decorative or technical purposes in a subsequent galvanic process.
• the metallizing In metallizing materials which per se have rough surfaces as in ceramic objects, wood and the like, the metallizing can be efifected in its individual phases after thorough degreasing and activation of the materials, without any further pretreatment.
• a roughening treatment either mechanical or chemical is absolutely necessary.
• ABS resins which is based on an oxidative etching with chrome sulfuric acid
• chrome sulfuric acid is rather difficult to carry out for, if the etching is too light, the desired eifect is not attained and it is also again lost by over etching.
• ABS graft polymers are relatively expensive so that their practical applicationis limited.
• the object of the invention is to provide a process for the adherent metallizing of non-conductors, especially synthetic resins and rubber, by the non-electrolytic deposit of an electrically conductive layer from a predominantly aqueous metal salt solution containing a reducing agent in the presence of metal deposit catalysing metals which is easy to perform on the most varied types of synthetic resins, such as, for example, polyvinyl chloride, polyethylene, polypropylene and the like, as Well as rubber, for instance, hard rubber.
• the essence of the invention resides in that the synthetic resin or rubber is prepared with a filler which on one hand has functional groups which are capable of chemically binding the catalyst and on the other hand provide the necessary roughness on the synthetic resin or rubber surface.
• the filler employed for the preparation can already contain the catalyst in chemically bound form or it is also possible first to prepare the synthetic resin or rubber with the filler and then treating the thus prepared resin or rubber with a solution of the catalyst, preferably, ammoniacal, to bind the catalyst on the filler. Following this the pretreated article is subjected to a known chemical metallizing treatment.
• a filler the secondary particle size of which is about 0.1a to about 1., preferably, about 1.0 to about 5p, so that the degree of roughness of the resin surface can be adjusted depending upon'the particle size of the filler.
• fillers which preferably contain free OH groups, for example, about 1 to about wt. percent so that Ag ions or Pd ions can be bound from an ammoniacal solution. This effect can be strengthened by the use of modified fillers. Silicas containing SiH bonds which possess reducing properties are especially suited for this purpose. The binding of the activation ions manifests itself by the more or less brown coloration of the filler or respectively the resin.
• the synthetic resin or rubber is prepared depending upon the type of filler employed, with about 10 to 50 wt. percent, preferably, up to 35 wt. percent of filler.
• Finely divided precipitated or pyrogenic metal or metalloid oxides in the form of single oxides, mixed oxides or oxide mixtures have proved especially advantageous as fillers.
• the precipitated fillers include all fillers (having the prerequisite functional groups for chemical bonding of the catalyst) which are prepared by wet processes, during which they may also be charged with catalytic metal ions.
• the pyrogenic fillers are produced from volatile metal or metalloid compounds by vapor phase hydrolysis or oxidation in a flame.
• a homogeneous mixture of, for example, a volatile metal or metalloid halide, such as, silicon tetrachloride in the vapor phase and a gas forming water on combustion and air or oxygen and, if desired, an inert gas is converted to the oxide and hydrochloric acid in a flame.
• a volatile metal or metalloid halide such as, silicon tetrachloride in the vapor phase and a gas forming water on combustion and air or oxygen and, if desired, an inert gas is converted to the oxide and hydrochloric acid in a flame.
• vaporized mixtures of several metal halides, such as, silicon tetrachloride and aluminum chloride are employed in place of a single halide, so-called mixed oxides can be obtained in which each primary particle already consists of the oxides.
• the filler particles at the surface of the synthetic resin or rubber article prepared with the filler according to the invention can be dissolved out, for example, by an alkaline treatment prior to the metallization thereof.
• the bonding of the catalyst is effected on the lower lying filler particles after the alkaline pretreatment.
• the charging of the filler with the catalytic active ions can be effected by treatment with an ammoniacal metal salt solution which can be carried out before the filler is incorporated in or applied to the synthetic resin or rubber which is to be prepared therewith or after the synthetic resin has already been prepared with said filler.
• the synthetic resin or rubber is washed thoroughly with water and then introduced into the metallizing bath which, as is known, generally essentially consists of a salt of the metal to be deposited, a complex former, a stabilizer and a reducing agent, such as, for example, a hypophosphit'e, borazane, boranate'or formaldehyde.
• the metallizing bath which, as is known, generally essentially consists of a salt of the metal to be deposited, a complex former, a stabilizer and a reducing agent, such as, for example, a hypophosphit'e, borazane, boranate'or formaldehyde.
• the process according to the invention can also'be carried out in that the non-conductor is prepared with a dispersion of the filler, preferably, an aqueous dispersion, which is already charged with the catalytically active ions and which contains an anchoring agent known per se which contains a cationically active material and after. drying to leave a film of the activation filler thereon, subjected to the metallizing process.
• This procedure is especially applicable for metallizing clear synthetic glass materials which are only to be metallized and galvanized on one side.
• Such procedure is also particularly suited for preparing cellulose hydrate films for metallizing as such films can be charged with catalytically active ions at the same time an antiblocking agent is applied thereto by treatment, for example, with a stable silica suspension.
• the process according to the invention can also be used in instances where it is desired to protect the decorative effect of a metallic coating on a shaped metal base, such as, iron or aluminum against corrosion, such as, for example, in the case of automobile bumpers.
• the rough metal base is first provided with a protective coating of a filler containing synthetic resin in which the filler is charged with the catalytically active ions and such coating provided with the conductive metal coating over which a thicker coating of decorative metal (chrome or nickel) is applied galvanically.
• Metal bases coated in this way are protected against corrosive attack even when the decorative metal coating is damaged and also prevents the formation of local cells.
• the advantages of the process according to the invention reside in that mechanical roughening of the surfaces of the article to be metallized is not required and also aside from the possible leaching out of the upper layers of the filler chemical roughening need not be carried out. In addition, sensitization with SnI-I or the like becomes entirely unnecessary. In the instance where the filler already charged with active ions (Pd++, Ag+) is incorporated in the article to be metallized separate activation is not necessary.
• the process according to the invention therefore is a substantially simplified metallizing process especially as the incorporation of fillers in synthetic resins and especially rubber in many instances renders it possible to provide other advantageous properties therein.
• a further advantage of the process according to the invention resides in the optimum adherence of the metallizing coating obtained in view of the chemical bond over the activators which are chemically bonded to the filler.
• the degree of roughness can be controlled by suitable selection of the particle size of the filler employed.
• fillers In addition to the fillers mentioned above, other fillers, provided they have the necessary functional groups for chemically binding the catalyst required for the electroless metallization, can be used for the purposes of the invention.
• alkali metal silicates, alkaline earth metal silicates or. their mixed silicates, as well as aluminum silicates can be used in an analogous manner to the wet precipitated silica employed in Example 1,
• the process of the invention also is not limited to the use of the $0 size, namely, for example, about 2 m to 500 mp, preferably, 5 m to 30 m
• the finely divided wet precipitated silicas and silicates. and pyrogenic silicas which can be essentially pure silicas onin the form of, mixed oxides or co-coag ulates of silica with, for instance, 0.5 to 1.5 wt. percent of A1 0 which are commercially available as various grades of Aerosil which have BET surface areas ranging from about 60 to about 380 mF/g.
• Suitable finely divided precipitated sil were, for instance, are commercially available as Ultrasil VN 2 and Ultrasil VN 3 (having other oxide contents below 1 wt. percent) as well as Durosil (having an Na O content of about 2 wt. percent). Such precipitated silicas upon calcination suffer a weight loss of about 12%. Both the pyrogenic and the wet precipitated silicas employed according to the invention can be hydrophobized, for example, by treatment with methyl chlorosilanes to provide products containing about 1-3% of bound carbon. Suitable finely divided precipitated silicates, for instance, are the commercial product Calsil containing about 69-70 wt. percent of SiO;, and about 10-11 wt.
• the surface areas of the finely divided fillers employed according to the invention can, for instance, range between about 10 mfi/g. and 400 m. g.
• the metallizing of the pretreated synthetic resins and rubber according to the invention can be carried out with good results with the well known metallizing baths under the usual conditions, such as, for example, are illustrated in Metalloberflache, No. 8, pages B133-B138 (1965), and in Metal Finishing, Electroless Plating Today, Dr. Edward B. Saubestre, June 1962, pages 67-73, July 1962, pages 49-53, August 1962, pages 45-49 and September 1962, pages 59-63.
• EXAMPLE 1 Wet precipitated silica with a 6 wt. percent content of silanol groups having a secondary particle size of 1-5 and a primary particle size of 16 m was worked into three batches of high pressure polyethylene on mixing rollers to provide a silica content of 10 wt. percent, 20 wt. percent and 30 wt. percent in the respective batches. Plates 2 mm. thick were molded from each of the batches as well as from the unfilled high pressure polyethylene.
• EXAMPLE 2 Three batches of unplasticized polyvinyl chloride powder were mixed with quantities of silica of a secondary particle size of 8-2J8IL and a primary particle size of 16 111,11. which had been treated with silicochloroform to charge it with Si-H groups, such as to provide silica contents of 10 wt. percent, 20 wt. percent and 30 wt. percent. The resulting mixtures were then processed to form bands in an extruder which were cut into plates. These plates and an unfilled polyvinyl chloride plate were then metallized as described in Example 1(a).
• EXAMPLE 3 Mixtures of polypropylene with 10 wt. percent, 20 wt. percent and 30 wt. percent of a pyrogenic silica of a secondary particle size of 10-40 mg which had previously been charged with Ag' ions from an ammoniacal solution containing 0.5 g./l. of Ag NO were prepared on mixing rollers. Plates 2 mm. thick were molded from such mixtures and hung together with an unfilled polypropylene plate for 15 minutes in a chrome sulfuric acid bath at 50 C., then washed with hot water (60 C.) and then introduced into a metallization bath of the composition given in Example 1 Without further activation.
• a process for metallizing a non-conductor wherein a base of synthetic resin or rubber is metallized by nonelectrolytic deposition thereon of a metal comprising the steps of distributing a silica filler throughout said resin or rubber prior to molding; then molding the resin or rubber to the desired shape to form said base; then applying a metal catalyst for the deposition of the metallizing metal to said base, the metal catalyst being in the form of a solution of a salt of the catalyst metal, and the catalytically active ions of said metal salt being chemically bound to said filler through free OH groups present on the surface of the filler, the amount of said filler being at least 10% by weight of said resin or rubber and the said amount of filler being sufiicient to provide for a strong bond with said catalyst; and then subjecting the thus prepared base to treatment with an aqueous solution of the salt of the metallizing metal in the presence of a reducing agent for the latter metal salt so as to cause formation of a catalytically promoted firmly

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• Chemical & Material Sciences (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)
• Inorganic Chemistry (AREA)
• Chemically Coating (AREA)

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Publications (1)

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Family Applications (1)

Country Status (7)

Cited By (7)

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• 1966
  • 1966-09-08 CH CH1300266A patent/CH522744A/de not_active IP Right Cessation
  • 1966-10-07 FR FR79206A patent/FR1496278A/fr not_active Expired
  • 1966-10-18 NL NL6614641A patent/NL6614641A/xx unknown
  • 1966-11-08 BE BE689458D patent/BE689458A/xx unknown
  • 1966-11-11 GB GB5075466A patent/GB1164459A/en not_active Expired
  • 1966-11-12 JP JP7438766A patent/JPS525540B1/ja active Pending
• 1970
  • 1970-02-04 US US3672937D patent/US3672937A/en not_active Expired - Lifetime

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