DD211128A1 - METHOD FOR THE STRIPLESS APPLICATION OF A METAL LAYER ON NITRILE GROUP-CONTAINING POLYMER SURFACES - Google Patents

Abstract

The aim and task is to develop a reliable and economical process for the activation of nitrile group-containing polymer surfaces. By formation of catalytically active nuclei, the surface should be pretreated for the subsequent electroless metallization. According to the invention, the object is achieved by pretreating a polymer containing nitrile groups with hydroxylamine solution and then bringing it into contact with a copper salt solution. The germinated surface can be easily metallized.

Description

Title of the invention

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Process for the electroless deposition of a metal layer on nitrile group-containing polymer surfaces

Field of application of the invention

The invention relates to a method for applying catalytically active nuclei to nitrile-containing polymer surfaces for the subsequent electroless metal deposition.

Characteristic of the known technical solution

Numerous methods are known for producing metallized surfaces.

So far, the surfaces to be subsequently metallized have been treated either with colloidal noble metal dispersions or with noble metal complex solutions (DE-OS 2 941 997). An important part of the growth of these methods is the considerable consumption of precious metals, which entails considerable financial costs. It is furthermore known to treat the substrate surface to be metallized with a bath solution of a reducible non-noble metal (Gu, ITi, Co, Pe), to dry it and to catalytically act by thermal fixation (DE-OS 2 462 435) or use of a suitable reducing agent Metal nuclei for the subsequent metallization to form (DE - OS 2 265 194). This method also has numerous disadvantages. The germs formed have a much lower activity. The high solubility of the metal salts leads to a partial dissolution of the adhering salt, so that thereby the reduction effect of the subsequent metallizing bath is impaired. Other sensitization and activation methods that involve the chemical modification of polymer surfaces

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The goal is to apply a well-adhering metal film (for example, the effect of ozone on unsaturated bonds in a polymer surface layer DE-GS 3 012 746), are very time, material and energy consuming.

Object of the invention

The object of the invention is to develop a process for activating nitrile group-containing polymer surfaces, which is reliable and economical and enables electroless metal deposition without the use of conventional noble metal activation baths.

Explanation of the essence of the invention

The invention has for its object to provide a method for the formation of catalytically active nuclei in the polymer surface layer. By germination, the surface should be pretreated so that a firmly adhering coating is formed by chemical-reductive metallization.

According to the invention the object is achieved in that a nitrile-containing polymer is first pretreated by the action of hydroxylamine so that arise in its surface layer reductive acting centers. For this purpose, the nitrile group-containing polymer is immersed in Bine hydroxylamine solution, and then the treated polymer is brought into contact with a copper salt solution, wherein catalytically active active nuclei are deposited on the surface of the polymer. The germinated in this way polymer surface can be metallized in a simple manner in a conventional manner by the action of a metal-depositing bath solution.

The reductive centers incorporated in the polymer surface layer according to the invention are stable to air,

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so that the process can be interrupted for any length of time before the metal nuclei are applied. The inventive treatment of the polymer surface with hydroxylamine solution results in the reduction of the copper ions to copper nuclei contained in the solution only at the polymer surface solution boundary layer. A possible separation of the germs on Reaktionsgefäßwandungen is excluded.

The resulting in the polymer surface layer reductive centers act simultaneously nucleating and activating, so that a good anchoring of the metal nuclei on the polymer surface is ensured and forms a firmly adhering coating in the subsequent metallization. In the electroless plating bath, a rapid and uniform coverage of the polymer surface with a reducible metal occurs.

In the present activation method only copper compounds are used. The results obtained are equivalent to conventional noble metal activation. Suitable base materials for the activation according to the invention and subsequent metallization are organic substances having a nitrile group content of more than 10%, such as films, rubber, plastics, paper, fibers and fabrics. Reductive centers are generated in the polymer surface layer by contacting the polymer with a hydroxylamine-containing solution. Alcohols, water, but also dimethylformamide or solvent mixtures have proven to be preferred as median.

After completion of the hydroxylamine action, a short interlayer wash to remove nonadherent hydroxy-1-amine solution should be made.

Subsequently, the wet or dried polymer is heated with a copper (I) or copper (II) salt solution. As salts, all are at least 0.001 % soluble in the selected solvent, such as. As halides, sulfates, nitrates and acetates.

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To increase the nucleation rate ammonium salts or ammonia (o, 1 - 1 %) are added to the copper salt solution expediently.

Implementation objectives

example 1

9 g of polyacrylonitrile fiber were treated in a solution of 300 ml of water and 12 g of hydroxylamine acetate for 30 minutes at 85 ⁰ C, washed and resuspended in 300 ml of a 0.01% Kupfeiv / Uj chloride solution for 5 minutes at 70 ⁰ C. The activated · showed Paser a yellowish to brownish color and allowed to metallize electrolessly in a conventional manner. · A treatment in a conventional copper / formaldehyde bath gave a shiny metallic pinning copper coating after 2 minutes · The surface resistance was measured to be 10 M · cm ·

Example 2

9 g of an acrylonitrile-Acrylsäuremethylesterfilms (70: 30) was 1 minute heating in a solution of 300 ml of methanol and 8 g of hydroxylamine at the boiling point, washed and resuspended in 300 ml of a 1 #igen copper-fr]} - chloride solution for 5 minutes at 90 ⁰ C treated and washed. The film also had a yellowish to brownish color. A conventional nickel chloride / hydrazine bath gave a firmly adherent metallic nickel coating after 2 minutes; with a surface resistance of 20 .Λ. cm.

Claims (4)

- 5 Erfindaanspruch 244486 1. A method for electroless deposition of a metal layer on nitrile-containing polymer surfaces, wherein on the polymer surface for metal deposition catalytically active nuclei are formed, characterized in that the surfaces of the nitrile-containing materials are first treated with a solution containing hydroxylamine or its salt, washed and then brought into contact with a solution containing at least one copper salt, wherein from the solution catalytically active copper nuclei are deposited on the polymer surface, so that the thus treated surface is electrolessly metallized. 2. The method according to item 1, characterized in that the polymer contains at least 0.001 % organic reductive acting centers. 3. The method according to item 1, characterized in that the reaction is carried out with free hydroxylamine, a hydroxylamine solution or a Hydroxylaminsalzesung using as solvent water, methanol, ethanol or other solvents are used in which hydroxylamine or hydroxylamine salts to at least 0.01 % are soluble. 4. The method according to item 1, characterized in that as Kupfersalζ copper (II) sulfate, nitrate, acetate, citrate, tartrate, halide, copper (II) - and copper (I) complex salts , Copper (I) halide, rhodanide or sulfite and as a solvent, water, alcohol or another solvent is used in which said salts are at least 0.001 % soluble.