JPS6354791B2 - - Google Patents

Abstract

1. Process for activating metallic and non-metallic surfaces for the purpose of currentless metal deposition, characterized in that a) the surface to be metallized is wetted with an organometallic compound from the series comprising butadiene palladium dichloride, diacetonitrile palladium dichloride, diacetonitrile platinum dichloride and dibenzonitrile palladium dichloride, which compound is stable towards air and moisture and is dispersed in an organic solvent, b) the organic solvent is removed and c) the organometallic compound adhering to the surface to be metallized is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides currentless metal deposition.
Activation of metallic and non-metallic surfaces for deposition.

A conventional method for currentless production of metal coatings on nonconducting or semiconducting substrates is to clean the substrate surface, immerse it in a bath containing stannous chloride or other stannous salts, and then apply the desired metal. by immersing the substrate in a bath of a metal salt, such as silver nitrate, gold chloride, palladium chloride or platinum chloride, which promotes the precipitation of the stannous ions adsorbed onto the substrate and/or the reducing agent contained in the currentless metal salt bath. The metal ions in the bath are then reduced to form the center of the catalytically activated surface to obtain the catalytic core, and the catalytically activated surface is then treated with a solution of the desired metal in the presence of a reducing agent. the desired metal, for example copper, nickel or cobalt, {see, for example, G. Muller, "Metals for Synthetics", Eugen G. Leutze Verlag, Saulgau
(1966)}.

This and similar methods are commonly referred to as "ionic activation."

German Patent No. 1197720 describes a method for activating the surface of polymers during plating. In this method, tin chloride () is mixed with hydrochloric acid/
It is based on a combination of sensitization and activation steps by introduction into a palladium chloride solution.

During this process, a colloidal solution of metallic palladium is created, which is believed to be stabilized by stannic acid and tin oxychloride. For this reason, this method is commonly referred to as "colloidal activation." In the next step, an appropriate concentration of acid,
Activated with alkalis or salts to remove protective colloids, the palladium particles are catalyzed in an electrolyte for nickel chemical plating operations.

These activation methods have the disadvantage that they require several processing steps (activation, sensitization, washing, etc.) to complete, making the currentless metallization method complicated and therefore expensive. have. Furthermore, the method is not widely applicable, but rather is generally limited to substrates whose surfaces have been pretreated by chemical or mechanical means.

Surprisingly, a novel, mild and simple method for activating metallic and non-metallic surfaces has been discovered, which is effective without any pre-treatment even on difficult-to-metallize surfaces. can be provided with an adhesive metal.

Accordingly, the present invention provides a) a method for treating the surface to be metallized with an organic compound of the series including butadiene palladium dichloride, dicyclopentadiene-gold() chloride, diacetonitrile palladium dichloride, diacetonitrile platinium dichloride and dibenzonitrile palladium dichloride. a) a metal compound which is stable to air and moisture and is wetted with the organometallic compound which is dispersible in an organic solvent, b) removes the organic solvent, and c) adheres to the surface to be metallized. The present invention relates to a method for activating metal and non-metal surfaces for currentless metal deposition, characterized by comprising the steps a) to c) above of reducing the organometallic compound.

For example, the organometallic compound can be dissolved in an organic solvent,
Alternatively, a slurry of the organometallic compound in a solvent may be used.

The surface can then be current-free metallized in a known manner.

In principle, all organometallic compounds are included,
The substrate can then be activated sufficiently for currentless metallization. However, when carrying out the method on a commercial scale, it is recommended that the following conditions be maintained. However, the present invention is not limited thereto.

(1) The organometallic compound used should be stable to air and moisture. They should be soluble in organic solvents, but only slightly soluble in water. Furthermore, they must become catalytically active compounds in currentless metallization reduced with customary reducing agents.

(2) Solutions of organometallic compounds in organic solvents should be stable to air and moisture.

(3) Organic solvents should be easily removed.

(4) No ligands harmful to the metallization bath should be liberated during the reduction of the organometallic.

(5) The reduced active nuclei should stick to the substrate surface in the aqueous solution to prevent the decomposition of the bath by carried metals.

The method is generally performed as follows.

Organometallic compounds of elements of Groups 2 and 2 of the Table of Contents, Au, Pd and Pt with olefins and nitriles as organic components, most especially divalent palladium and platinum with olefins. Compounds such as butadiene palladium dichloride, compounds with nitriles such as diacetonitrile palladium dichloride, diacetonitrile platinium dichloride or dibenzonitrile palladium dichloride, and monovalent gold olefin complexes such as dicyclopentadiene-gold() chloride. Dissolve in an organic solvent. Of course, mixtures of the above compounds can also be used. The concentration of organometallic compounds is between 0.01 and 10
g/, but may be higher or lower in some cases.

The following are particularly suitable as organic solvents:
Namely, methylene chloride, chloroform, 1,
Polar protic and aprotic solvents such as 1,1-trichloroethane, trichlorethylene, perchlorethylene, acetone, methyl ethyl ketone, butanol, ethylene glycol, dioxane and tetrahydrofuran.

Mixtures of the abovementioned solvents, and blends with other solvents such as petrol, ligroin, toluene, etc., can of course be used.

In the method according to the invention, the surface of the substrate to be metallized is wetted with these solutions, the operation preferably lasting from 1 second to 1 minute. Particularly suitable for this purpose are methods in which the substrate is immersed in the solution or the substrate surface is sprayed with an activating solution. Of course, according to the method of the invention, the activation solution can be applied by stamping or printing methods.

The following are suitable as substrates in the method of the invention: i.e. steel, titanium, glass, quartz,
Ceramics, carbon, paper, polyethylene, polypropylene, ABS-plastic, epoxy resin,
polyester, polyamide, polycarbonate,
and textile sheet structures consisting of polyamides, polyesters, polyalkylenes, polyacrylonitrile, polyvinyl halides, cotton and wool, and mixtures or mixed polymers thereof;
Threads and fibers.

After infiltration, remove the organic solvent. in this way,
Preferably, the low boiling solvent is removed by evaporation, for example under vacuum. In the case of high boiling point solvents,
Other methods are suitable, such as extraction methods using solvents in which the organometallic compound is insoluble.

The surface impregnated in this way must then be activated by reduction. For this purpose, it is preferable to use the reducing agents customary in plating technology, such as hydrazine hydrate, formaldehyde, hypophosphorous acid or borane. Of course, other reducing agents can also be used. Preferably, the reduction is carried out in an aqueous solution. However, alcohol
Solvents such as ethers and hydrocarbons can also be used. Of course, suspensions or pastes of reducing agents can also be used.

The surface thus activated may be used directly for currentless metallization. However, it is also necessary to clean the surface by washing off the residues of the reducing agent.

The most preferred embodiment of the process of the invention consists in carrying out the reduction operation directly in the metallization bath with the reducing agent of the currentless metallization operation. This embodiment simplifies currentless metallization, which was previously impossible. This extremely simple embodiment consists of only three steps (reduction and metallization ).

This embodiment is particularly suitable for nickel baths containing amine-borane or copper baths containing formalin.

The following are preferred metal baths that can be used in the method of the invention. That is, baths containing nickel salts, cobalt salts, iron salts or mixtures thereof with copper salts, gold salts and silver salts. This type of metallization bath is known in the art of currentless metallization.

Example 1 An ABS plastic product with a structured surface is
Spray uniformly with a solution of 0.1 g of butadiene palladium dichloride in chloroform ("Freon 12" is the propellant).

Then, dry at room temperature and add 30 g of nickel chloride/
Dimethylaminoborane 3g/and citric acid 10
The sample was immersed in an alkaline nickel-metsuki bath containing 1.5 g/g/g, and the bath was adjusted to pH 8.1 with ammonia. about 30
After a few seconds, the surface began to darken and after 10 minutes a shiny nickel layer, which was effectively adhered, was deposited.

Example 2 A 13 x 13 cm ² piece of polyester/cotton cloth (plain weave) is immersed for 30 seconds in a solution of 0.3 g of dicyclopentadiene-gold() chloride in 1 liter of chloroform, dried at room temperature and then according to Example 1: Nikkelmettsuki for 20 minutes in an alkaline nickelmetuki bath. A shiny piece with a metallization of 12% by weight of nickel is obtained. The electrical resistance was 1.7 ohms in the warp direction and 3.5 ohms in the weft direction.

Example 3 Plain weave polyacrylonitrile fabric (copolymer of 93.6% acrylonitrile, 5.7% methyl acrylate and 0.7% sodium methallylsulfonate)
13 x 13 ^cm2 in a solution of 0.01 g of diacetonitrile palladium dichloride in 100 ml of methylene chloride.
It was dipped for seconds, dried at room temperature and then nickel plated for 10 minutes in an alkaline nickel plating bath according to Example 1. A glossy piece with a metal coating of 10% by weight of nickel and an electrical resistance of 2.8 ohms in the warp direction and 6.7 ohms in the weft direction was obtained.

Example 4 A thread "Wevenit" made of fiber yarn (Nm40) obtained from polyester polymer (100% polyethylene terephthalate) is immersed in an activation solution according to example 3 for 30 minutes at room temperature. The solvent is allowed to evaporate at room temperature and then the knitted fabric is soaked in sodium borohydride.
It was immersed in a solution containing 0.5 g/ml for 1 minute. Next, wash the cloth with water and add 0.2 mol of nickel () chloride/
, containing citric acid 0.15 mol/and sodium hypophosphite 0.2 mol/, using ammonia 25
It was introduced into an aqueous solution whose pH was adjusted to 9.0 at ℃. about
After 15 seconds, the textile sheet structure begins to darken.
After 30 seconds, the fabric is already covered with a thin layer of nickel metal and darkens.

After about 10 minutes, the nickel layer is 0.2 μm thick.
The cloth was removed from the bath, washed with water and dried. The weight increase was 23% based on the total weight of the knitted fabric. The surface resistance of a 10×10 cm ² cut from the fabric was 3.6 ohms in the wale direction and 4.2 ohms in the transverse direction.

Example 5 A fabric made from polyacrylonitrile multi-yarn (100% polyacrylonitrile) was immersed in an activation solution according to Example 1 for 1 minute. The sample was then dried at 40°C and the pH was adjusted to 12~12 using soda solution.
13 and containing 10 g of copper sulfate, 15 g of Seignette salt and 20 ml of 35% formaldehyde solution.

After about 45 seconds, the surface of the fabric begins to darken and after about 2 minutes, a metallic copper shine appears. After approximately 20 minutes, the sample is removed from the metallization bath, thoroughly washed, and air dried. The copper layer thickness was approximately 0.2 μm.

The surface resistance, measured in the warp direction, of a 10×10 cm ² sample was 0.6 ohm.

Example 6 10 x 10 cm ² of fibrous carbon cloth was mixed with butadiene palladium dichloride per liter of methylene chloride.
It was immersed in a solution containing 0.05 g for 30 seconds, dried at room temperature and then nickel plated for 20 minutes in an alkaline nickel plating bath according to Example 1.
A shiny piece of material was obtained with a metallization of 16.9% by weight and whose resistance was 0.3 ohm.

Example 7 A 30×30 cm glass plate was sprayed homogeneously with the activation solution according to Example 1, dried and then immersed in an alkaline nickel plating bath according to Example 1 for 7 minutes. After 80 seconds, the surface darkens; after 5 minutes,
A glossy layer was seen. The glass plate is cleaned after metallization,
It was dried and coated with a metallic reflective layer.

Example 8 A 30x30 cm polyethylene film was degreased using methylene chloride and then sprayed on one side with the activation solution according to Example 1. After drying, the film is metallized according to Example 1 in a nickel plating bath for 20 minutes. A film plated with nickel on one side was obtained, the nickel content of which was 10.8 g/m ² .

Example 9 10m x 15cm web, 0.1g of butadiene palladium dichloride per 1 liter of methylene chloride.
The containing solution was pulled through a padding device at a speed of 160 m/h and dried at 40° C. without tension. The web material is then treated with nickel sulfate.
A metallization bath containing 27 g/h, dimethylaminoborane 3 g/h and citric acid 14 g/h was drawn through at a speed of 25 m/h. Retention time in the bath is 10 minutes. During the metallization operation, the PH, nickel concentration and reducing agent concentration were maintained by continuous replenishment. The web was then washed and dried. A uniformly nickel-plated web was obtained, the nickel coating being 30.5 g/m ² .

Example 10 A stamping pad was infiltrated with a 1 g slurry of dibenzonitrile palladium dichloride in 20 ml of ethylene glycol. Letters were embossed onto the polyethylene film using a stamp. The film was immersed in a water bath for 30 seconds and then nickel plated in a metallizing bath according to Example 1. After 5 minutes, the letters were clearly visible as a shiny surface.

Example 11 A 30×26 cm steel plate was degreased with 1,1,1-trichloroethane and then sprayed on one side with the activation solution according to Example 1 and dried. The plate was then immersed in a metallization bath according to Example 1 for 20 minutes.

A steel plate is obtained which is uniformly coated with a nickel layer of about 2 μm.

Example 12 A 14 cm x 14 cm polyethylene article was sprayed on one side with a solution of 0.1 g of butadiene palladium dichloride per liter of methylene chloride ("Freon 12" is the propellant), dried at room temperature and then Example 1 According to the above, the material was nickel-metalized in an alkaline nickel bath for 15 minutes. A shiny and effectively adhered nickel layer was obtained on the polyethylene product, the electrical resistance of which was 7 cm ohms.

Example 13 An 8 x 11 cm polypropylene net was evenly sprayed with a solution of 0.1 g of butadiene palladium dichloride per liter of methylene chloride (“Freon 12”).
is the propellant), dried at room temperature and then nickel plated according to Example 1 in an alkaline nickel bath for 15 minutes. A shiny, effectively nickel-plated polypropylene net was obtained, but with an electrical resistance of 3 ohms.

Example 14 A 4x6 cm polyamide plate was sprayed with the activation solution according to Example 1, dried and then immersed in an alkaline nickel plating bath according to Example 1 for 10 minutes. A polyamide plate plated with nickel on one side is obtained, the nickel content of which is 4.2
g/m ² and resistance was 5 ohms.

Example 15 A 15 x 15 cm polycarbonate plate was sprayed with the activation solution of Example 1, dried and then immersed in an alkaline nickel plating bath according to Example 1 for 15 minutes. A polycarbonate with a reflective metal layer was obtained after washing and drying, the resistance of which was 4 ohms.

Claims (1)

[Claims] 1 a) Surface to be metallized with butadiene palladium dichloride, dicyclopentadiene-
Organometallic compounds of the series including gold() chloride, diacetonitrile palladium dichloride, diacetonitrile platinium dichloride and dibenzonitrile palladium dichloride, which organometallic compounds are stable to air and moisture and dispersible in organic solvents. b) removing the organic solvent; and c) reducing the organometallic compound attached to the surface to be metallized. Methods of activating metallic and non-metallic surfaces for metal deposition.