JPS61288079A - Production of molded polyester article having metallized surface - Google Patents

Abstract

PURPOSE:To improve the adhesion, the friction and shock resistances of a formed film by treating a molded polyester article with a palladium soln. under prescribed conditions to activate the surface before chemical plating. CONSTITUTION:An activating soln. contg. 0.1-20ppm palladium is prepd. A sensitized molded polyester article is treated with the soln. at >=50 deg.C to activate the surface. This surface activated article is chemically plated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a surface metallized polyester molded article with good adhesion of a metal film by a chemical plating method.

(Prior art) Conventionally, in order to apply chemical metal plating to the surface of plastic, the workpiece is usually subjected to pretreatment such as degreasing, sensitization, and activation, and then immersed in a main chemical plating bath. However, surface treatments such as mechanical etching and chemical etching are also used to improve wetting of the substrate surface to improve adsorption and adhesion of the catalyst, or to improve adhesion and adhesion between the substrate and metal. are often used together. Japanese Patent Publication No. 49-17856
The publication states that when applying metal chemical plating to polyester resin, an etching effect was obtained by alkali treatment, and the amount of alkali salt on one surface or carboxyl group was increased and sensitization treatment was performed for a long time to adsorb a large amount of Sn. After that, a method is described in which an activation treatment is performed to adsorb a large amount of Pd, and the activation treatment is performed to facilitate chemical metal plating.

However, since the adsorption power of palladium to polyester molded products is extremely small, palladium often falls off from the molded products after activation, resulting in no chemical plating or uneven plating. Even if the conductive molded product manufactured in this manner has a relatively uniform metal coating, the metal may fall off due to friction or an extremely weak impact. Furthermore, in the activation treatment of polyester, the palladium concentration has conventionally been set at 200 to 300 ppm, perhaps by analogy with other resin plating cases (see JP-A-48-4459 and JP-A-49-17856). ) treatment with a highly concentrated activation solution was considered to be the usual condition.

(Problems to be Solved by the Invention) When applying chemical plating to a polyester molded product, the present invention effectively activates the surface of the molded product with an extremely dilute palladium solution in advance to maximize the catalytic effect. The object of this invention is to produce a surface-metallized polyester molded product having a uniform metal coating with extremely good adhesion and excellent friction resistance and impact resistance.

(Means for solving problems) The present invention has a first order configuration.

In other words, after sensitizing a polyester molded product,
The gist of this invention is a method for producing a metal-surfaced polyester molded article, which is characterized by treating it with an activation solution containing 0.1 to 20 ppm of palladium, and then applying chemical plating.

The polyester used in the present invention mainly includes terephthalic acid (hereinafter abbreviated as TPA) and ethylene glycol (
Hereinafter, it will be abbreviated as EC. ), polyethylene terephthalate (hereinafter abbreviated as PET), and TPA
and 1,4-butanediol (hereinafter abbreviated as BD).
Abbreviated as T:), the acid component is isophthalic acid in addition to TPA.

Dicarboxylic acids such as naphthalene dicarboxylic acid, adipic acid, and sebacic acid may be contained up to about 30 molar acids.On the other hand, in addition to PG or BD, diol components such as propylene glycol, 1.4 cyclohexane dimetatool, and Ethylene glycol and the like may be contained as long as they are less than 30 molar, and additives such as dyes and pigments may also be present.

Molded products in the present invention include films, injection molded products, plates,
This term refers to all forms of articles, such as rods and bags of bottles.

Further, the palladium solutions used in the present invention include palladium chloride, palladium nitrate, and palladium sulfate.

Water of palladium compounds such as potassium chloride palladate.

Any solution using alcohol, ketone, glycol, acetic acid, etc. or a mixed solvent thereof may be used, but an aqueous solution is most preferable. In addition, metal palladium can be mixed with concentrated nitric acid,
After dissolving in concentrated sulfuric acid and concentrated hydrochloric acid.

It may be diluted with the above solvent.

In the present invention, polyester molded products are subjected to conventional degreasing.

It is preferable to perform sufficient sensitization treatment after the alkali treatment. Degreasing and alkali treatment may be carried out by any commonly used method, but neutral or weakly alkaline detergents are preferred for degreasing, and aqueous solutions of sodium hydroxide or potassium hydroxide are preferred for the alkali treatment liquid from the viewpoint of effectiveness and economy. Most preferred.

In the subsequent sensitization treatment, a stannous chloride-hydrochloric acid acidic solution is preferably used as the treatment liquid.

The sensitized polyester molded article is then immersed in an activation treatment solution with a dilute palladium concentration. The palladium concentration at this time needs to be 0.1 to 20 ppm, and the treatment temperature is preferably 50° C. or higher. If the palladium concentration is 0.1 ppm or less, the absolute amount of palladium is small, so a large bathtub is required, and therefore the treatment time becomes long, which is not practical. 20
If it exceeds ppm, adsorption of palladium will progress significantly, especially in fabrics and multifilaments with a large number of fibers, resulting in more activity than necessary, and plating will occur rapidly during chemical plating, resulting in poor adhesion. As the polyester becomes weaker, particles of the metal to be plated, such as Ni, which have not fully adhered to the polyester, become nuclei and leave behind in the plating bath, resulting in the disadvantage of shortening the life of the plating bath. Therefore, the palladium concentration is 0.1-20pp
It is necessary to be within the range of m.

The most preferred palladium concentration is between 0.5 and 15 ppm. On the other hand, if the treatment temperature is 50°C or lower, the palladium adsorption reaction rate will be low, so it is preferably 50°C or higher. Although it is possible to carry out the process under pressure at a temperature of 100°C or higher, it is most preferable to carry out the process at a temperature in the range of 60 to 95°C.

The adsorption reaction rate of palladium according to the present invention is remarkable at high temperatures, and the higher the concentration, the more effective it can be, but the effect differs depending on the shape of the molded article and other factors.

The test is carried out by selecting appropriate conditions in advance within the limited range of the present invention.

In some cases, polyester molded products activated by 5K are coated with chemical plating after cleaning, and metals such as nickel, copper, cobalt, chromium, and silver are applied to the polyester surface to form a uniform metal with extremely good adhesion. It can be formed as a film. As for the chemical metal plating bath, the type of metal may be selected depending on the purpose, but from an economical point of view, it is preferable to use nickel or copper.1Usually, a nickel-hypophosphorous acid based chemical plating bath with an odor due to the plating speed is used. Most preferably, it is used.

(Function) In general, polyester molded products cannot be plated because they do not easily adsorb Pd, which is an activation catalyst, during normal degreasing and sensitization treatments.
It is also said that plated metals have poor adhesion; however, the present inventors believe that if the polyester molded product has been subjected to sensitization treatment, the palladium will be stronger in an extremely dilute Pd solution. Adsorbed and adsorbed palladium does not fall off even when washed with water for a long time, even when rubbed with two hands or rubbed, and after washing with water, there is no decrease in activity even when air-dried day and night, making it stable. It was discovered that an adsorption bond is formed. On the other hand, palladium has a remarkable ability to adsorb hydrogen and is a strong reduction catalyst.
It is known that it expands 00 times and becomes brittle.

Palladium acts as an initial reduction reaction catalyst in chemical plating and promptly deposits the plating metal. Thereafter, the deposited plating metal itself acts as a catalyst to continue the reduction reaction, and the plating reaction progresses. In the chemical plating process, when a large amount of palladium covers the surface of the substrate, the catalytic action is strong and the chemical plating progresses rapidly, but it absorbs hydrogen and expands significantly, leaving the brittle palladium between the substrate and the plating. Because of this, the adhesion between the base material and the plated metal is weakened.

Based on the above-mentioned Kikumi, the present inventors have developed a method for applying chemical plating with good adhesion to polyester molded products.

It is preferable that the amount of palladium be as small as possible within the range that maintains the activity as an initial reduction catalyst, and on the other hand, we have found that it is better to use a solution as dilute as possible in order to uniformly adsorb and bond the surface of the substrate. It has come to this.

In other words, the two main points of the present invention are (1) the maximum catalytic effect achieved with the minimum necessary amount of palladium, and (2)
The two points are that the interference with adhesion is suppressed by keeping the excess amount and weight to a minimum.

The adhesion between Sn and Pd by this method is strong, and excess palladium can be removed by washing with water to achieve the desired purpose.

By applying chemical plating to polyester molded products that have been pretreated in this way.

A surface metallized polyester molded article having a uniform metal coating with extremely excellent adhesion can be obtained.

(Example) Next, the present invention will be explained in more detail with reference to Examples.
Physical properties in Examples were measured by the following method.

(11 Surface Resistance The surface metallized molded product was left in a humidity-controlled room at 20°C and 40% RH for one day, and the contact distance between the poles was 5 mm, and the distance between the two poles was 1.
It was sandwiched between the front and back screens as Ocrn and connected to the terminals of an electrometer, and the resistance sound was measured with the electrometer. IC the measured value! It was converted to 1 surface resistance per n.

(2) Thickness of plated part Average value of thickness of plated part and its variation σy1-1
was determined from electron micrographs taken at five arbitrary locations on the cross section of the fiber.

(3) Peeling test using adhesive tape After applying adhesive cellophane tape to adhesive cellophane tape (24 w II + width) on the plated film by pressing it 3 times with a hard rubber roller under a load of 1 mm, this was peeled off at a peel angle of 135 mm.
The cellophane tape was pulled off at a speed of 10I17F+/second, and those in which the plating film did not come off at all along with the cellophane tape were evaluated as good.

Example 1 A polyester molded product made by injection molding polyethylene terephthalate having an intrinsic viscosity [η)=0.74 at 290° C. into a rectangular shape with a thickness of 5 cm was washed with warm water in which a weakly alkaline detergent had been dissolved. Add this to a 20% by weight sodium hydroxide solution (liquid temperature 9
0°C) for 20 minutes, washed to roughen the surface, and then immersed in a 5% by weight stannous chloride-hydrochloric acid acidic solution for 1 hour to sufficiently sensitize. I washed it with water.

Next, it was immersed in an activated aqueous solution (bath temperature 70°C) containing palladium chloride at a palladium concentration of 3 ppm for 5 minutes, then passed through running water, washed, and then placed in a nickel-hypophosphorous acid chemical plating bath at 75-80°C. After immersion for 2 minutes, a surface metallized polyester molded product with excellent metallic luster and no uneven metal coating was obtained. The performance was measured and shown in Table 1.

As is clear from Table 1, the metal coating was uniform and had good conductivity, the peel test results were also good, and it was found that the plating had extremely excellent adhesion.

Example 2 A polybutylene terephthalate molded product was degreased and then sensitized without alkali reduction.

A surface metallized polyester molded article was obtained in the same manner as in Example 1, except that the palladium chloride solution was replaced with a methanol solution and the activation treatment conditions were as listed in Table 1.

As is clear from Table 1, the surface metallized polyester molded product was uniform and had good adhesion.

Examples 3 and 4 A surface metallized polyester film was obtained in the same manner as in Example 1, except that a PET film was used as the workpiece and the activation treatment was performed under the conditions listed in Table 1.

As is clear from Table 1, the surface metallized polyester film was uniform and had good adhesion.

Comparative Example 1 A surface metallized polyester molded article as shown in Table 1 was obtained in the same manner as in Example 1, except that the palladium concentration was 500 ppm and the treatment was carried out at room temperature. The polyester molded product had poor plating ability, and its peel strength could not be measured.

Comparative Examples 2 and 4 The surface metallized polyester molded products listed in Table 1 were obtained in the same manner as in Example 2, except that the palladium concentration was 500 ppm and the temperature and treatment time were changed. In Comparative Example 2, the plating formation ability was poor despite being treated at room temperature for a long time, and in Comparative Example 4, which was treated at high concentration and high temperature, the activity was too strong and metal nuclei were generated in the solution during plating. The plating bath became unusable. In addition, all of the molded products were surface metallized polyester having a metal coating with poor adhesion to the plated metal.

Comparative Example 3 A surface metallized polyester film as shown in Table 1 was obtained in the same manner as in Example 3 except that the palladium concentration was 0.05 ppm. The film was a surface metallized polyester film with a thin plating layer and low conductivity.

(Effect of the invention) The effects of the method of the present invention are as described below.

(11) Since the activation treatment performed by the method of the present invention is a stable and highly active pretreatment, it has become possible to manufacture uniform metal-coated polyester molded products with extremely excellent adhesion to the plated metal. The durability of the parts was also very good.

(2) In the present invention, activation treatment is performed at 50°C or higher.

The activation processing time is 1% compared to the conventional method that takes less than that.
It was also shortened to 15 to 1150, and the operability was significantly improved.

(3) The amount of radium used, which is expensive and has a large impact on manufacturing prices, is about 1/20 to 1/1000 compared to conventional methods, and there is almost no loss due to cleaning, etc., so economic efficiency has been significantly improved. .

(4) Because an extremely dilute palladium solution is used.

Excess radium other than adsorbed palladium (excess palladium is eluted into the plating bath and shortens the life of the plating bath) can be completely removed by washing with water, extending the life of the chemical plating bath. .

(5) In addition, polyester molded products pretreated as in the present invention do not lose their activity even after long-term storage.
Therefore, it has the remarkable effect of being able to obtain a surface-metallized polyester molded product with excellent adhesion in just the time required for chemical plating treatment, and is an extremely innovative manufacturing method for surface-metallized polyester molded products. be.

(6) The surface metallized polyester molded article according to the present invention is
It is suitable for shielding materials, antistatic materials, magnetic properties materials, antenna materials, etc., and can also be used as a base for electrolytic plating.

Claims (2)

[Claims] (1) A method for producing a metal-surfaced polyester molded product, which comprises sensitizing the polyester molded product, treating it with an activation solution containing 0.1 to 20 ppm of palladium, and then applying chemical plating. (2) The method according to claim 1, wherein the activation treatment is performed at a temperature of 50°C or higher.