JPS621876A - Method for plating molded body of polyethylene terephthalate with metal - Google Patents

Abstract

PURPOSE:To simply form a metallic film having superior adhesion by plating with high reproducibility by etching a molded body of polyethylene terephthalate and immersing it in palladium hydrosol contg. a cationic surfactant. CONSTITUTION:A molded body of polyethylene terephthalate is etched by immersion in an aqueous soln. of an alkali metallic hydride for >=about 10min. the molded body is then immersed in palladium hydrosol contg. a cationic surfactant to stick palladium colloid to the surface of the molded body. About 0.002-0.1% stearyltrimethylammonium chloride is preferably used as the surfactant. The palladium hydrosol contains bout 0.1-2mg atom/l Pd and the immersion is preferably carried out at room temp.-about 100 deg.C for >=about 1min. The molded body is pulled up, washed and chemically plated by a conventional method.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a metal plating method for a polyethylene terephthalate molded body, and more specifically, a polyethylene terephthalate molded body (hereinafter simply referred to as a PUT molded body). By applying palladium colloid having a certain high catalytic activity to the surface of the PET molded body and then chemically plating it, a metal plating film with excellent adhesion can be formed on the surface of the PET molded body with good reproducibility with a simple operation. The invention relates to a metal plating method that has been made possible.

The main uses of the PET molded body on which the metal coating according to the present invention is formed are as decorative materials and as electromagnetic shielding materials for EtIf countermeasures since conductivity and magnetic functions are produced depending on the type of metal coating formed. , capacitor materials, magnetic recording tapes, etc.

[Conventional technology]

Since the surface of a PET molded product is generally inert, in order to form a metal film on the surface of a PET molded product by chemical plating, the surface of the PET molded product must be etched beforehand, and then the surface of the PET molded product must be etched to cause a reduction reaction of metal ions. It is necessary to apply palladium as a catalyst to the surface of the PET molded body.

Conventionally, methods for adding palladium to the surface of PET molded bodies include, for example, Journal Saipu Applied
Fisifukus (Journal of Applied
36 (1965), page 948.

In this method, chromic acid is added to a solution of stannous chloride in hydrochloric acid.
P etched with sulfuric acid and sodium hydroxide
Two steps: sensitization treatment in which the ET molded body is immersed and then washed with water, and activation treatment in which the sensitized PET molded body is immersed in an acidic solution of palladium chloride in hydrochloric acid to precipitate palladium on the surface of the PET molded body. Consisting of

Furthermore, as a method for imparting palladium in one step, there is, for example, the method described in US Pat. No. 301)920.

The method described in US Pat. No. 301)920 involves contacting a substrate with a strongly acidic palladium-tin colloidal solution to provide palladium which acts as a catalyst for chemical plating. This strongly acidic palladium-tin colloidal solution can be used, for example, as a palladium-tin colloidal solution.
tion of theInstjtutg of
Metal Finishing) Volume 51 (197
3) As described on page 63, it is used for activation treatment of ABS resin, etc., but it is not used for PεT molded bodies.

(Problem to be solved by the invention) In the case of the method described in the above-mentioned journal Saipu Applied Physics, two baths of stannous chloride and palladium chloride are required, and it is necessary to prevent the two baths from mixing with each other. The process is extremely complicated as it requires washing with water after each treatment.Moreover, the catalyst activity for chemical plating is low, so the reduction reaction of metal ions must be repeated two to three times. It has the disadvantage that sufficient palladium cannot be added to cause the reaction.

In the case of the method described in the above-mentioned US Pat. No. 301)920, a large amount of tin hydroxide etc. is applied to the substrate in addition to palladium which acts as a catalyst for chemical plating, so these impurities are This impedes the reduction reaction in chemical plating and causes a weakening of the adhesion strength between the formed metal film and the substrate. Therefore, after bringing the substrate into contact with a strongly acidic palladium-tin colloidal solution to remove impurities other than palladium, it is necessary to further immerse the substrate in an acid or alkaline solution (acceleration treatment).

Moreover, this strongly acidic palladium-tin colloidal solution changes over time and begins to precipitate 3 to 4 months after its preparation, resulting in poor stability and reproducibility.

As mentioned above, we have established a method to form a highly reproducible metal plating film with excellent adhesion by applying palladium with a certain high catalytic activity to the surface of a PUT molded body through a simple operation, and then chemically plating it. The current amount is also required.

[Means to solve the problem]

The present inventor has arrived at the present invention as a result of various studies on a method of imparting palladium having a certain high catalytic activity to the surface of a single PET molded body through a simple operation.

That is, the present invention involves etching the surface of the target PET molded body with an aqueous solution of alkali metal hydroxide, and then immersing it in palladium hydrosol (colloidal solution) containing a cationic surfactant. This is a metal plating method for a PET molded body, which comprises applying palladium colloid to the surface of the PET molded body, and then chemically plating it.

(Function) First, the most important point in the present invention is that PET is etched in advance with an aqueous solution of alkali metal hydroxide.
A palladium hydrosol containing a cationic surfactant is used to apply palladium colloid that acts as a catalyst for chemical plating to the surface of a molded article.

In the present invention, the palladium hydrosol containing a cationic surfactant is extremely stable, so it can be stored for a long period of time and can be used at any time. Since it does not contain any impurities, it does not require the acceleration treatment that conventional methods require, so a constant high catalytic activity can be achieved by simply immersing it in palladium hydrosol containing a cationic surfactant. A palladium colloid can be applied.

Next, various conditions for implementing the method of the present invention will be described.

Various types of PET molded products such as sheet-like, powder-like, belent-like, and filament-like PET molded products can be used as the PET molded product in the present invention.

The etching treatment of PET molded bodies at Zero Hatchi and Meiji is P
E↑ The molded body is immersed in an aqueous alkali metal hydroxide solution at a temperature ranging from room temperature to the boiling point, preferably from 50 to 90°C for 10 minutes or more. Furthermore, the P[! T
It is preferable that the molded body is previously degreased with ethanol or the like, washed with water, and dried.

As the alkali metal hydroxide aqueous solution used in the etching process in the present invention, a sodium hydroxide or potassium hydroxide aqueous solution is suitable, and the concentration thereof is 1 to 1/7! is desirable.

The palladium hydrosol containing a cationic surfactant in the present invention is prepared by adding an aqueous solution of palladium salt such as palladium chloride (7) to sodium borohydride, hydrazine, etc. in the presence of a cationic surfactant as a protective agent. or by adding and mixing a cationic surfactant into palladium hydrosol produced in the absence of a cationic surfactant ( For example, Japanese Patent Application Laid-Open No. 59-120249).

As the cationic surfactant, a quaternary ammonium salt type surfactant such as stearyltrimethylammonium chloride is suitable, and it can be added before or after the reduction treatment. A nonionic surfactant or a water-soluble polymer such as polyvinylpyrrolidone may be added as a protective agent.

The concentration of cationic surfactant is 0.002-0.1%
A range of is preferred.

The palladium concentration in the palladium hydrosol used in the present invention is preferably in the range of 0.1 to 2 B-ato+a/l.

In the present invention, the PET molded body is immersed in palladium hydrosol containing a cationic surfactant for 10 to 10 minutes from room temperature.
This can be carried out by immersing at a temperature in the range of 0° C. for at least 1 minute, preferably at least 10 minutes, followed by pulling up and washing with water.

Chemical plating in the present invention can be performed by a conventional method. That is, in a solution containing metal ions and a reducing agent, the metal ions are reduced in the palladium colloid portion, thereby precipitating the metal.

The metal ion solution for chemical plating in the present invention includes one or more of neutral or alkaline nickel, cobalt, copper, etc., which are commonly used to impart electrical and magnetic properties. can be used.

As the reducing agent for chemical plating in the present invention, sodium hypophosphite, formaldehyde, etc. can be used.

〔Example〕

Next, the present invention will be explained by examples.

The magnetism in the examples was measured in a magnetic field of 10 kOe.

Is the conductivity TI? 6141 current generator (Takeda Riken ■
! ! and An-531) were measured by the four-terminal method using a pressure gauge (manufactured by &D91).

The surface abrasion was measured using an MCP-TESTER-LORESTA low resistance surface resistance meter (manufactured by Mitsubishi Yuka Corporation).

The adhesion of the plating was examined by strongly pasting Scotch mending tape (manufactured by Jujutsu 3M) onto the plated object and peeling it off one hour after the completion of plating.

Example 1 PE washed with ethanol for 10 minutes, then washed with water and dried
T film (manufactured by Dianail ■1) 00, thickness 10
0μ Sardine, 3csX2cn+) at 3.3 mol/
1 in an aqueous solution containing potassium hydroxide at 80°C,
After 60 minutes, the sample was pulled up and washed with water to perform etching treatment.

Separately, 50 μl O1 of palladium chloride (9) was added to 2.5 μmol of an aqueous solution containing 250 μmol of sodium chloride.
ml and then diluted to 94 ml with pure water. While vigorously stirring this solution, an aqueous solution In1) containing stearyltrimethylammonium chloride 1)1) was added to the 6K solution, followed by sodium borohydride 20L1).
0μIIIo! When 5 ml of an aqueous solution containing cationic surfactant was added dropwise, the color of the solution suddenly changed, and a transparent black-brown palladium hydrosol containing a cationic surfactant was obtained.

The above etched PET film was immersed in the resulting palladium hydrosol containing a cationic surfactant at room temperature for 60 minutes, then pulled out and washed with water. The surface of the PE film was a thin gray color, indicating that chemical plating was not present. Palladium colloid was added for the purpose.

Next, 2 m of nickel chloride (MlO,I IIol)
ol/j! Dissolved in 500 ml of ammonia aqueous solution,
0.21) ol/1 sodium hypophosphite 500
ml, the PET film provided with the palladium colloid was immersed at a temperature of 60° C. into a nickel chemical plating solution obtained by adjusting the pH to 8.9 with concentrated hydrochloric acid. After about 10 seconds of immersion, the entire surface of the PUT film turned black and nickel began to precipitate. After 10 minutes, the film was pulled up, washed with water, and dried to obtain a PET film whose surface was uniformly coated with nickel and had a metallic luster. The thickness of the nickel film determined from the weight increase of the film before and after plating was 0.95 μm, and even when the mending tape was strongly pressed against this surface and peeled off, the nickel film did not peel off at all.

Moreover, the surface resistance of this PET film was 32Ω.

Example 2 PE washed with ethanol for 10 minutes, then washed with water and dried
T film (manufactured by Dia Honil 1) 125, thickness 1
25 μm.

3 cm'X 2 cab) to 3.3 mol, #! immersed in an aqueous solution of 80°C containing sodium hydroxide,
After 0 minutes, the sample was pulled up and washed with water to carry out etching treatment.

Separately, palladium (9) chloride 501J l1o
1 was dissolved in 2.5 ml of an aqueous solution containing 250 IIol of sodium chloride and then diluted to 94 ml with pure water.

While vigorously stirring this solution, 1 ml of an aqueous solution containing 1 g of polyvinylpyrrolidone was added, and then 5 ml of an aqueous solution containing 200 IIol of sodium borohydride was added dropwise.The color of the solution suddenly changed and a black-brown transparent palladium hydrosol was added. was gotten. Add to this palladium hydrosol 5 m of stearyltrimethylammonium chloride.
A palladium hydrosol containing a cationic surfactant was obtained by adding 5 ml of 1fflo of an aqueous solution containing g and stirring for 15 minutes.

The above etched PBT film was immersed in the resulting palladium hydrosol containing a cationic surfactant at room temperature for 30 minutes, then pulled up and washed with water. The surface of the PUT film turned uniformly pale gray and palladium colloid was added. It had been.

Then 0.8 mol#' Lofcel salt, 0.8 t
aol/1 sodium hydroxide and 0.5 mol/f
Copper sulfate 005 hydrate was dissolved in pure water to make 100ml,
Furthermore, the PET film to which palladium colloid was applied was immersed in a steel chemical plating solution prepared by mixing 100 ml of a 35% formaldehyde solution. 10
After being immersed for a minute, the film was pulled up, washed with water, and dried to obtain a PUT film coated with a copper metal film having a thickness of 0.14 μm and exhibiting red gloss and good adhesion.

Even when the mending tape was strongly pressed against the surface of this PET film and removed, the copper coating did not peel off at all.

In addition, the conductivity of this Pr:,T film is 2.2XI
It was O'S/cm.

Example 3 0.03 mol cobalt sulfate (]D hexahydrate, 0.2
5 mol sodium hypophosphite, 0.5 mol
Sodium tartrate dihydrate and 0.50 mol of boric acid were dissolved in pure water to obtain lβ, and 3.3 mol of it was dissolved in pure water.
/ It was added with an aqueous sodium hydroxide solution to adjust the pH to 9.
0, and a cobalt chemical plating solution was prepared.

In this cobalt chemical plating solution, a PE film (manufactured by Toshi ■, thickness 20.8 μm 13 cm x 2 co
d) was soaked at a temperature of 90°C. After 3 minutes of immersion, it is pulled out, washed with water, and dried to reveal a metallic luster with the surface uniformly coated with cobalt. A film was obtained.

Even when the mending tape was strongly pressed against the surface of this PH7 film and peeled off, the cobalt film did not peel off. In addition, the saturation magnetic flux density of this PET film is 13400
Gauss, and the coercive force was 8810e.

Example 4 PE washed with ethanol for 10 minutes, then washed with water and dried
T film (east side type, thickness 20.8/jm, 4c
mX2.5cm) is 6.0 mol/7! Etching treatment was carried out by immersing the substrate in an aqueous solution containing sodium hydroxide at 50° C., and removing it after 60 minutes and washing it with water.

The PET film to which palladium colloid was applied in the same manner as in Example 1 was immersed in a cobalt chemical plating solution obtained in the same manner as in Example 3.

After 2 minutes of immersion, the film was pulled out, washed with water, and dried to obtain a PET film with a metallic luster whose surface was uniformly coated with cobalt.

Even when the mending tape was strongly pressed against the surface of this PUT film and peeled off, the cobalt film did not peel off. In addition, the saturation magnetic flux density of this PET film is 8560 G
auss and coercive force was 8080e.

Comparative Example 1 A strongly acidic palladium-tin colloidal solution was prepared according to the procedure of Example 1 of US Patent No. 301)920. PUT film subjected to ethanol cleaning and etching treatment in the same manner as in Example 2 (manufactured by Dai 7 Nail ■, 1) 25
, 125 μm thick, 3 cm×2 cm) was immersed in the freshly prepared palladium-tin colloid solution at room temperature. After 60 minutes, the PET film was pulled up and thoroughly washed with water, and then the PET film was
ff sodium hydroxide solution at room temperature. 5
After soaking for a minute, the PET film was pulled up and thoroughly washed with water to remove impurities other than palladium.
The sample was immersed in a nickel chemical plating solution in the same manner as above, but no plating occurred.

Comparative Example 2 Nickel chemical plating was attempted in the same manner as Comparative Example 1, except that a palladium-tin colloid solution that had been used for 3 months after UR production was used.

A nickel metal film was only formed on a small portion of the PUT film surface. Note that the palladium-tin colloidal solution that had been prepared for a long time of 4 months or more was partially or completely agglomerated to form a blackish brown precipitate.

〔effect〕

As shown in the above example, the method for metal plating a PET molded body according to the present invention is such that the palladium hydrosol used in the present invention does not contain impurities that interfere with the catalytic action of chemical plating, and can be used for a long period of time. Since it is stable, it is possible to provide a palladium colloid with a certain high catalytic activity, and it is therefore possible to form a metal plating film with excellent adhesion on the surface of a PUT molded body.

Claims (1)

[Claims] (1) When forming a metal film on the surface of a polyethylene terephthalate molded body by chemical plating, after etching the target polyethylene terephthalate molded body with an aqueous solution of alkali metal hydroxide, palladium containing a cationic surfactant is used. 1. A method for metal plating a polyethylene terephthalate molded body, which comprises applying palladium colloid to the surface of the polyethylene terephthalate molded body by immersing it in a hydrosol, and then chemically plating the polyethylene terephthalate molded body.