JPH02301568A - Method for coating synthetic resin structure with metal - Google Patents

Abstract

PURPOSE:To form a uniform metal coating film on a synthetic resin structure by electroless plating in a tightly adhered state without reducing the physical strength of the structure or damaging the structure by activating the surface of the structure under mild conditions. CONSTITUTION:A basic nitrogen compd. such as methylamine, glycine or ethyl azide is dispersed in a resin binder such as polyamide and stuck to the properly pretreated surface of a synthetic resin structure to be coated with a metal by dipping, spraying, coating or other means. A metal coating film is then formed on the structure by electroless plating as usual.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of metal coating the surface of a synthetic resin structure, and more specifically, when forming a metal film on the surface of a synthetic resin structure by electroless plating, a plating process is performed prior to electroless plating. The present invention relates to a method for forming a uniform metal coating with excellent adhesion by attaching a basic nitrogen-containing compound to the surface of the target.

Generally, in order to perform electroless plating on the surface of plastics, it is common to immerse the plastics that have undergone pretreatment such as degreasing, catalysis, and activation in an electroless plating bath. Surface treatments such as mechanical etching or chemical etching are often used in combination to improve the wetting of the metal and to improve the absorption and adhesion of the catalyst, or to improve the adhesion between the base material and the metal. It is being said.

Currently, plastics that are industrially targeted for electroless plating include ABS resin, polypropylene resin, polyamide resin, and the like. This is because these materials are easily chemically etched and have relatively good adhesion during electroless plating.

On the other hand, examples of resins that are said to be difficult to plate include polyester resins, vinyl chloride resins, and vinylidene chloride resins.

Regarding the chemical etching of these resins, for example, Japanese Patent Publication No. 47-19600 describes that prior to plating resins such as polyamide, polyester, polyvinyl chloride, polyvinylidene chloride, and polyolefin, an organic solvent suitable for each resin is used. For example, for polyvinyl chloride resin, ethyl acetate, acetone, benzene, trichlene, etc., for polyester resin, m-cresol, a 10 to 20% aqueous solution of phenol, and for polypropylene, For example, add 10-2 to 5% caustic soda aqueous solution.
0% decalin is mixed with organic solvents such as tetralin,
Furthermore, a swelling treatment is performed at 50 to 60°C in an emulsion bath etc. by adding 2~log/Q of surfactant,
Next, add 2 to 60% potassium dichromate to a 50 to 60% sulfuric acid aqueous solution.
1-2 at 50-70°C in a bath with 5g/12
A method of performing electroless plating after etching for a minute is disclosed. However, the organic solvent used to swell the resin in this method evaporates easily, has a unique odor, and is flammable, which poses a risk of contaminating the working environment and causing fire. Furthermore, the mixed solution of sulfuric acid and potassium dichromate used as a chemical etching agent after swelling treatment has strong oxidizing power, and there is a concern that it may cause problems such as loss of polymer substances and decrease in physical strength. . Moreover, wastewater containing dissolved chromic acid is subject to strict pollution regulations, and the wastewater treatment method is complicated, and furthermore, there are many difficulties in the treatment of chromium-containing sludge collected by precipitation.

On the other hand, one way to improve the adhesion of electroless plated metal films is to add fine irregularities to the surface of synthetic fibers, but mechanical The method of roughening is
In the case of fibers, the damage is so great that it is practically impossible.

In addition, JP-A-60-181362 discloses an improved method for chemically plating polyester fibers, in which polyester fibers containing a compound having sulfonic acid groups and/or metal sulfonate groups are immersed and/or passed through an alkaline bath. By doing so, a weight loss treatment of 8 to 30% by weight is performed,
A method has been disclosed in which a uniform electroless plated metal film is formed by exposing metal sulfonate groups on the fiber surface and then applying a catalyst and activating the group. however,
In this method, in order to carry out melt spinning in which a compound containing a metal sulfonate group coexists in the polyester spinning raw material, it must be specially prepared from the spinning raw material stage. There are disadvantages such as nozzle wear and thread breakage during spinning.

Furthermore, JP-A No. 48-54299 describes a method for electroless plating of polyamide fibers, and this method involves applying alcohol to N-alkoxymethyl nylon without physically or chemically etching the polyamide fibers. The solution is applied to nylon fibers and then rapidly dried at a temperature higher than the boiling point of the solvent alcohol. In this method, the alcohol quickly vaporizes during drying, forming fine bubbles and forming N-alkoxymethyl It detaches from the surface of the nylon and the N-alkoxymethyl nylon is firmly adhered to the nylon fiber. Since the surface of N-alkoxymethyl nylon becomes finely uneven due to vaporization and dissipation of alcohol, a metal plating layer is formed by direct electroless plating without chemical etching with a mixture of dichromic acid and sulfuric acid. becomes possible. However, this method requires the use of alcohol as a solvent for N-alkoxymethyl nylon, and also requires a step of rapidly heating and vaporizing the alcohol above its boiling point, which poses the drawback of a fire hazard. have.

The main purpose of the present invention is to activate the surface of a synthetic resin structure to be electrolessly plated under simple and mild conditions in order to eliminate the above-mentioned drawbacks in electroless plating of a synthetic resin structure. It is an object of the present invention to provide a method for forming a uniform and firmly adherent metal coating without causing a decrease in physical strength or damage to a synthetic resin structure.

Thus, according to the present invention, in the method of forming a metal film on the surface of a synthetic resin structure by electroless plating, prior to electroless plating, a basic base is added to the surface of the synthetic resin structure on which the metal film is to be formed. Provided is a method for metal coating the surface of a synthetic resin structure, which comprises depositing a resin binder containing a nitrogen-containing compound.

The synthetic resin structures to be treated by the present invention include threads (filaments, fibers, yarns, etc.);
It includes fiber structures such as cotton-like materials, tows, woven materials, knitted materials, and non-woven materials, as well as rod-like, plate- or film-like casings, and cylindrical shapes. The material of such a structure is not particularly limited, and examples thereof include polyamide, polyolefin, polyester,
It can be made of various synthetic resins such as vinyl chloride, vinylidene chloride, polyacrylic, polycarbonate, and ABS.

When performing electroless plating on the surface of such a synthetic resin structure (hereinafter referred to as a base material), the method of the present invention includes applying a basic nitrogen-containing compound to the surface of the base material to be plated prior to plating. It is characterized in that the surface of the base material is activated by attaching a resin binder containing the following.

When carrying out such activation treatment on a base material, prior to said treatment, appropriate pretreatments such as degreasing, scouring, surface wettability, etc. that are usually performed in electroless plating of synthetic resin base materials are carried out. can be done. For example, the base material can be degreased and refined by immersing it in an aqueous solution containing a suitable surfactant under heating. Furthermore, treatments such as physical surface roughening or chemical etching can also be applied.

According to the present invention, a resin binder containing a basic nitrogen-containing compound is attached to the surface of the base material which has been appropriately pretreated in this manner. The basic nitrogen compounds that can be used in the present invention include basic nitrogen-containing groups such as amino, ammonium, azine, azo, azoquine, diazo, diazoamino, diazonium, hydrazi, sidragino, hydrazo, hydrazine, oxyamino, and imino. Included are aliphatic compounds having at least one aliphatic compound, and these compounds may exist in the form of a dimer or higher polymer depending on the case. Preferred specific examples of such basic nitrogen compounds include the following.

(1) Aliphatic amine compounds: For example, primary aliphatic amines such as methylamine, ethylamine, propylamine, butylamine; secondary aliphatic amines such as dimethylamine, diethylamine, diethylamine, nitrimethylamine, triethylamine ,
Tertiary aliphatic amines such as tripropylamine; quaternary aliphatic ammonium compounds such as tetramethylammonium chloride, tetraethylammonium chloride, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetramethylammonium iodide. Or polyamines which are multimers of the above amines.

(2) Amino M: For example, glycine, sarcosine, dimethylglycine, betaine, ethylenediaminetetraacetic acid, hydantoic acid, creatine, alanine, a-aminobutyric acid, valine, leucine, σ-aminobutyric acid, serine, cycloserine, σ- Oxyalanine, cysteine, lysine, arginine, arginofuccinic acid, aminomalonic acid, asparagine a, a+σ-diaminosuccinic acid, succinimide, glutamic acid, etc. These amino acids can also be used in the form of salts, for example sodium or potassium salts.

(3) Others: Ethyl azide, diethyl azocarboxylate, 2-azoxy-2,5-dimethylhexane, ethyl diazoacetate, dicyandiamide, sodium methylisodiazotate, hydrazine, hydrazoic acid, hydrazone, α-oxyaminonitrile, tubusourea Such.

As a method for attaching the basic nitrogen-containing compound described above to the surface of a substrate, there is a method in which the compound is dispersed in a suitable resin binder and applied to the surface of the substrate. The resin binder has strong adhesion and flexibility to the surface of the base material, is compatible with basic nitrogen-containing compounds, and is compatible with solvents (e.g., water, alcohols, esters, or their like). Suitable resins include polyolefin resins, polyester resins, polyamide resins, etc., and these can be combined with melamine resins and acrylic resins as necessary. It can be used in combination with other emulsions.

The above-mentioned basic nitrogen-containing compound and resin binder can be applied to the surface of the substrate as a solution or dispersion in which they are dissolved or dispersed in the above-described solvent. The concentration of the basic nitrogen-containing compound in the solution or dispersion at that time is
Although it varies depending on the type of compound, etc., it is generally 0. O
It can be within the range of 1 to 20 g/Q, preferably 0.05 to 1 Og/Q, and the concentration of the resin binder is usually 0.1 to 100 g/Q as solid content, preferably 0.1 A range of ~50 g/Q is suitable.

Further, examples of means for applying such a solution or dispersion to the surface of the substrate include dipping treatment, spraying treatment, coating treatment, and the like.

Furthermore, if necessary, the solution or dispersion may contain a cationic, nonionic, amphoteric, or other surfactant to improve the wettability of the substrate surface.

The temperature during treatment with a resin binder solution containing a basic nitrogen-containing compound is usually room temperature, but in some cases it may be heated to a temperature of up to about 40°C.

The basic nitrogen-containing compound can be attached to the surface of the substrate by removing the solvent by a conventional method from the substrate to which the solution or dispersion has been applied.

Further, when a crosslinking-curing resin is used as the resin binder, heat treatment can be performed under the temperature and time conditions required for crosslinking and curing the resin. For example, when melamine resin is used as part of the resin binder, it usually has a molecular weight of about 80 to about 150.
Preferably, the heat treatment is carried out at a temperature in the range of 1 to 5 minutes.

The amount of the basic nitrogen-containing compound deposited varies depending on the type of basic nitrogen-containing compound used, but is generally 0.05 to 0.05.
It is convenient to have l Og/Q, preferably in the range from 0.05 to 5 g/Q.

According to the present invention, the base material to which the basic nitrogen-containing compound is adhered as described above is then coated with a metal coating by electroless plating (chemical plating). This electroless plating can be done using methods known per se, such as the Surface Treatment Technology Directory (
This can be done by the method described in literature such as (published by Industrial Technology Service Center). Specifically, for example, electroless copper plating can be performed by a reaction in which copper ions in a solution are precipitated as metal on the surface of the plated object using a reducing agent such as formaldehyde. The main reaction of electroless copper plating deposition is an autocatalytic reaction expressed by the following formula, when the Cu2+ complex in the plating solution is expressed as (Cu-chelating agent).

[Cu-chelate] +2HCHO+40H-→Cu'
+2HCOO-+H1↑+2H20+chelating agent Hypophosphite is the most common reducing agent for electroless nickel plating.

The basic reaction formula for electroless nickel plating is as follows (
acid bath).

Ni'+H! PO, -+2H" Next, the method of the present invention will be explained in more detail with reference to Examples.

Example 1 Polyester filament gauze (thread diameter 40 microns, 13
5 meshes/inch) was degreased and scoured for 30 minutes at 50°C in a 5 g/Q aqueous solution of a nonionic surfactant (Noigen WS-20; manufactured by Dai-Kogyo Seiyaku Co., Ltd.), and then dried.

Next, after heat setting in an atmosphere of 170°C for 1 minute to remove wrinkles, polyester resin (Fitex ES-
850; manufactured by Dainippon Ink) 50 parts by weight, melamine resin (
A pretreatment liquid containing 2 parts by weight of Beckamine PM-N (manufactured by Dainippon Ink), 0.5 parts by weight of a catalyst (Catalyst ES-2 (manufactured by Dainippon Ink), 1 part by weight of alanine, and 947 parts by weight of water). After immersion at 25°C''C'' for 1 minute and drying, heat treatment was performed at 100°C for 3 minutes.

A mixed solution of palladium chloride and tin chloride (Catalyst A-30; manufactured by Okuno Pharmaceutical Co., Ltd.) 159 ml (1), hydrochloric acid 160+RQ, and water 690 ml was prepared as a plating catalyst.

The treated polyester gauze was added to the plating catalyst solution for 25 minutes.
After immersing at °C for 2 minutes, washing with water, then immersing in a mixture of 50+++2 sulfuric acid and 950 ml of water as an activation bath at 45°C for 3 minutes, dissolving and removing tin chloride, and fixing palladium chloride to the fibers. I let it happen.

Next, after washing with water to remove excess sulfuric acid and the like, it was immersed in an electroless plating bath having the composition shown below at 28°C for 3 minutes, and a uniform copper plating film was formed.

Copper plating bath composition: Copper nitrate 15g/Q sodium bicarbonate lOl/tartrate
30 l/sodium hydroxide 20113
8% formalin solution 10 (JrnQ/QpH: 1
1.5 The formed copper layer has a 25% OWr and a surface electrical resistance of 0.3 Ω/cm or less, indicating a good metal film, confirming that the method according to the present invention is extremely effective. Ta.

Comparative Example J A polyester filament gauze that had been degreased, refined, and heat set in the same manner as in Example I was mixed with 50 parts by weight of a polyester resin (Finetex ES-850, manufactured by Dainippon Ink) and a melamine resin (Beccamin PM-N, Dai Nippon Ink). 2 parts by weight of catalyst (Catalyst ES-2; manufactured by Dainippon Ink), 0.5 parts by weight of catalyst (Catalyst ES-2; manufactured by Dainippon Ink), and 948 parts by weight of water were immersed at 25°C for 1 minute, then squeezed and dried. After, 1
Heat treatment was performed at 000C for 3 minutes.

Then, under the same conditions as in Example 1, 2
Although it was immersed at 8° C. for 5 minutes, only a patchy copper film was deposited on some parts.

The amount of copper film formed was only 8% OWf, and the surface electrical resistance was 108 Ω/cm or more, making it a poor conductor.

Example 2 Polyvinylidene chloride filament mesh (thread diameter 0.1
mm, 60 mm, 7 units/inch) with a nonionic surfactant (
Degreasing, scouring, washing with water, and drying were carried out for 60 minutes at 40° C. in a 5 g/(l aqueous solution of Meiselin X0-7, manufactured by Okusei Kagaku).

After that, polyester urethane resin (Hytran HW
-333; made by Dainippon Ink) 100 parts by weight, urethane resin (Hytran AP-10; made by Dainippon Ink) 20 parts by weight, crosslinking agent (CR-5L; made by Dainippon Ink) 25 parts by weight, polyamine (Hifix: A mixed aqueous solution of 1 part by weight (manufactured by Dainippon Pharmaceutical Co., Ltd.) and 954 parts by weight of water was uniformly applied by a spray method and dried at 40°C.

Next, heat treatment was performed at 50°C for 4 minutes, and then electroless plating was performed. The conditions for electroless plating were the same as in Example 1, and a uniform plating film was obtained.

The amount of the plated copper film was 18% OWf, and the surface electrical resistance was 0.3 Ω/cm, indicating a good conductive metal film and confirming that the method according to the present invention is effective.

Comparative Example 2 Same as Example 2, 7ionic surfactant (Meiselin xo
-7; Degreasing and scouring in a 5g/+2 aqueous solution
After washing with water, it was dried.

Thereafter, it was immersed in the same electroless plating bath as in Example 1 for 10 minutes, but a patchy copper film was formed. The surface electrical resistance of the formed copper film was 1010 Ω/cm or more, and it was a poor conductor.

Example 3 Polyvinyl chloride filament yarn (thread diameter 0.12 m)
m, 50 mesh/inch) was degreased in an aqueous solution of 5 g/Q of a nonionic surfactant (Meiselin X0-7, manufactured by Tasei Kagaku) at 50°C for 60 minutes, scoured, washed with water, and then dried.

Next, polyurethane resin (Hytran HW311: manufactured by Dainippon Ink) +00:It amount part, crosslinking agent (CR-5L)
, manufactured by Dainippon Ink), 1 part by weight of sodium ethylenediaminetetraacetate, and 896 parts by weight of water, the above filament Metsuyu was immersed at 25°C for 1 minute, dried, and dried at 50°C for 4 minutes. After heat treatment, electroless nickel plating was performed.

The plating conditions were as follows.

As a plating catalyst, 50 mQ of palladium chloride hydrochloric acid solution (Calaris l-OPC80; manufactured by Okuno Pharmaceutical Co., Ltd.) and 160 m of hydrochloric acid were used.
Prepare a mixture of Q and 790 mQ of water.

First r: The treated polyvinyl chloride mesh was immersed in the above solution at 25°C for 2 minutes and washed with water.

Next, add 45% to a mixture of 50 mQ of sulfuric acid and 950 rAQ of water.
It was immersed at °C for 3 minutes and washed with water to remove adhering sulfuric acid, etc.

After that, it was placed in an electroless nickel plating bath with the following composition at 32°C.
After dipping for 6 minutes, a uniform nickel film could be formed.

The amount of nickel plating deposited was 22% OW, the surface electrical resistance was 2.2 Ω/cm, and the conductivity was good, confirming that the method according to the present invention is excellent.

Nickel plating bath composition: Nickel hypophosphite 28g/Q boric acid
12tt ammonium sulfate
3 tt Sodium acetate 5
ttpH: 6.0 Comparative Example 3 In the same manner as in Example 3, polyvinyl chloride filament gauze which had been removed and refined was treated with polyurethane resin () 1 idran HW.
-311; manufactured by Dainippon Ink) 100 parts by weight, crosslinking agent (C
R-5L (manufactured by Dainippon Ink) and 897 parts by weight of water at 25°C for 1 minute, dried, and 50°
After heat treatment at C for 4 minutes, it was immersed in an electroless nickel bath for 15 minutes under the same conditions as in Example 3, but a nickel plating layer was only partially deposited, and the surface electrical resistance was 10"Ω/
cm or more, it was a poor conductor.

Example 4 Polyester filament gauze (thread diameter 40 microns, 13
5 mesh/inch) in a 5 g/Q aqueous solution of a nonionic surfactant (Meiselin
After degreasing at °C for 30 minutes, scouring, washing with water, and drying.

Next, 80 parts by weight of polyurethane resin (1 Idran AP-40; manufactured by Dainippon Ink), 5 parts by weight of melamine resin (Beccamin PM-N, manufactured by Dainippon Ink), and a catalyst (Catalyst ES-2; manufactured by Dainippon Ink) were added. 25 parts by weight of the above-treated polyester gauze was added to a mixture solution of 2 parts by weight of succinimide, 850 parts by weight of water, and 60 parts by weight of alcohol.
It was soaked for 1 minute at °C, squeezed out, and dried.

Next, after applying and activating a catalyst under the same conditions as in Example 1,
A uniform copper plating film was formed by immersing it in an electroless copper plating bath at 28°C for 2 minutes.

The deposited copper layer has a 28% OWf and a surface electrical resistance of 0.2
It was confirmed that the method of the present invention was extremely effective as it was a good metal film with a resistance value of Ω/cm or less.

Comparative Example 4 The polyester gauze subjected to the weight loss treatment in Example 4 was treated with polyurethane resin (Hytran AP-40; manufactured by Dainippon Ink) 80
parts by weight, 5 parts by weight of melamine resin (Beccamin PM-N, manufactured by Dainippon Ink), 2 parts by weight of catalyst (Catalyst ES-2; manufactured by Dainippon Ink), 850 parts by weight of water, and 60 parts by weight of alcohol. Soak at 25°C for 1 minute,
After squeezing and drying, it was heat-treated at 100°C for 5 minutes.

As a result of immersion in an electroless copper plating bath at 28° C. for 5 minutes under the same electroless plating conditions as in Example 1, a uniform copper plating film was formed.

The adhesion strength of the plated metal film was compared to the product of Example 4 and Comparative Example 4.
The results of the comparison of the products are shown in Table 1 below, and the product produced by the method of the present invention had better adhesion strength.

Measurement method> Gakushin friction test: JIS L 0849 load 200g
I rubbed it 50 times.

Cellophane tape method 2 Commercially available cellophane tape 5-7cm long
Cut it and firmly press it to the test surface.

After 10 minutes, that cellophane cheap plastic Peel off and transfer cellophane tape each time The fit was evaluated.

Claims (1)

[Claims] In a method of forming a metal film on the surface of a synthetic resin structure by electroless plating, prior to electroless plating, a resin binder containing a basic nitrogen-containing compound is applied to the surface of the synthetic resin structure on which the metal film is to be formed. 1. A method for coating a surface of a synthetic resin structure with metal, the method comprising: adhering metal to the surface of a synthetic resin structure.