JPS61281874A - Production for polyester molded article having metallized surface - Google Patents

Abstract

PURPOSE:To obtain a molded article having a metallic coating film excellent in adhesive force by alkali-treating a polyester molded article and thereafter performing successively the acidic liquid treatment, the sensitization treatment and the activation treatment and performing the chemical plating. CONSTITUTION:After alkali-treating a polyester molded article by using an NaOH aq. soln. or the like, it is treated in an acidic soln. such as an HCl aq. soln. or the like to neutilize excess alkali. Then in an ordinary method, it is subjected to the sensitization treatment preferably in the reduced pressure and successively the high activation treatment is performed thereto. After these treatments, the chemical plating such as Ni and Cu is performed. By this method, the polyester molded article having metallized surface which is uniform and excellent in adhesive force is obtained in the short-time treatment. This method can be applied for a molded article having the various shapes such as fiber, a dishcloth, a film and a hollow vessel.

Description

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

(Conventional technology) Conventionally, in order to apply chemical plating to the surface of plastics or synthetic fibers, the workpiece is subjected to pretreatment such as degreasing, sensitization, and activation, and then immersed in a main chemical plating bath. This is common, but it also improves the adsorption and adhesion of catalysts by improving the surface roughness of the substrate.

Alternatively, surface treatments such as mechanical etching and chemical etching are often used in combination to improve adhesion and adhesion between the base material and the metal. JP-A No. 49-17856 discloses that when chemically plating polyester resin, an etching effect is obtained by an alkali treatment, and a long-term sensitization treatment is performed by increasing the amount of alkali salt of one surface carboxyl group. A method is described in which after a large amount of Pd is adsorbed, an activation treatment is performed to adsorb a large amount of Pd, and the activation treatment is performed to facilitate chemical plating. However, when the base material is polyester fiber or a processed product thereof, the above method is not practical because the sensitization treatment requires a long time and the operability is extremely poor.

(Problems to be Solved by the Invention) The present invention proposes that when chemically plating a polyester molded product, the surface is roughened with an alkali, then treated with an acidic solution, and then subjected to a sensitization treatment. The present invention provides a method for manufacturing a polyester molded product having a uniform metal coating with good adhesion while shortening the sensitization time, which has been a bottleneck for improving properties.

(Means for solving problems) The present invention has the following configuration.

That is, in order to solve the above-mentioned problems, the present invention provides a method in which a polyester molded product is subjected to alkali treatment, then treated with an acidic solution, subsequently subjected to sensitization treatment and activation treatment, and then subjected to chemical plating. The gist of this paper is a method for producing a characteristic surface metallized polyester molded product.

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. ), but in addition to TPA, dicarboxylic acids such as isophthalic acid, naphthalene dicarboxylic acid, adipic acid, and sebacic acid may be contained as acid components up to about 15 mol; on the other hand, diol In addition to EG, the ingredients include propylene glycol, 1.4 cyclohexane dimetatool, tetramethylene glycol, triethylene glycol,
It may contain about 30 moles of recalls, etc., and additives such as dyes and pigments may also coexist.

The term "molded product" as used in the present invention refers to molded products of various shapes such as fibers, fabrics, C-ilms, and hollow containers.

Further, in the present invention, it is preferable that the polyester molded article is subjected to a normal degreasing treatment and then subjected to an alkali treatment. Degreasing and alkaline treatment may be carried out by any commonly used method, but neutral or weakly alkaline detergents are preferred for degreasing, and an aqueous solution of sodium hydroxide or potassium hydroxide is most preferred for the alkaline treatment liquid in terms of effectiveness and economy. It's better, □. The above degreasing and alkali treatment are described below. □ Degreasing and alkali treatment may be performed consecutively with the chemical plating process or separately. □ Degreasing and alkali treatment may be performed at ℃. The alkali-reduced polyester molded article is then treated in an acidic solution.

Subsequently, sensitization treatment is performed for several minutes to ten-odd minutes.

Prior to this sensitization treatment, it is extremely important to completely neutralize excess alkali with an acidic solution.1 This produces a remarkable effect that cannot be obtained by ordinary washing with water. Acidic solutions include organic acids such as acetic acid, formic acid,
As the inorganic acid, solutions such as hydrochloric acid, sulfuric acid, and nitric acid are preferred.

Among these acids, hydrochloric acid is most suitable, and an aqueous solution having an acid concentration of IN, which is the hydrochloric acid concentration of the sensitizing solution, is most preferable. In the sensitization treatment, a stannous chloride-hydrochloric acid solution is preferably used as the treatment liquid. Further, the sensitization treatment tank is preferably maintained under reduced pressure, particularly under reduced pressure of 50 to 200 mHg. This is done by defoaming and distributing the treatment liquid over the fine details of the molded product surface using reduced pressure.

This is to quickly remove H2 gas, which is a reaction product, without retaining it on the surface of the molded product or in the liquid.

Next, a high activation treatment is performed, and palladium chloride is the best activator, and a hydrochloric acid acidic solution having a concentration of approximately 2,000 ppm is preferable. In addition.

When carried out at a low concentration of 0.1 ppm to 20 ppm,
The activation temperature is preferably 50 to 100°C.

The palladium aqueous solution used in the present invention includes palladium chloride,
Any aqueous solution of palladium compounds such as palladium nitrate, palladium sulfate, potassium chloride palladate, etc. may be used.
Alternatively, metal palladium may be dissolved in concentrated nitric acid, concentrated sulfuric acid, or concentrated hydrochloric acid and then diluted with water.

Highly activated polyester molded products can be treated with a chemical plating bath to remove nickel, copper, cobalt, chromium, etc.
It is possible to produce polyester molded products having a uniform metal coating such as silver with extremely good adhesion.

The metal used for chemical plating may be selected depending on the intended use, but from an economical point of view it is preferable to use nickel or copper, and a nickel-hypophosphorous acid based chemical plating bath is usually best as it has a fast plating speed.

In the present invention, by providing an acidic bath after the alkaline treatment, and in some cases by lowering the pressure in the sensitization treatment tank, the sensitization treatment time is activated and is approximately the same as the treatment time in the main plating bath. It became possible to shorten the process to salt and perform continuous treatments ranging from alkaline treatment to chemical plating, and it also became possible to produce surface metallized polyester molded products with uniform and good adhesion.

(Function) In general, it is said that polyester molded products are less likely to be plated than other resin products, and that plated metals also have poor adhesion. The present inventors focused on the fact that uneven plating tends to occur when chemically plating polyester molded products, and conducted repeated research on the causes of inconvenience in the chemical plating process.

The alkali used in the surface roughening process is washed away.

It has been found that the sensitizer remains on the surface of the molded product and between the fibers, and local precipitation of the sensitizer due to this excess alkali causes uneven plating and deterioration of adhesion.

In other words, the gist of the present invention is after alkali roughening.

By treating with an acidic solution, the surface of the substrate is rendered acidic, preventing the sensitizer from precipitating and at the same time allowing the sensitizer to be firmly adsorbed. More preferably.

Appropriate pressure reduction during sensitization process promotes defoaming.

It is also possible to more uniformly adsorb the sensitizer onto the surface of the molded article.

According to the method of the present invention, the chemical plating process can be carried out in a continuous process because it is possible to perform the process in a short time.

It is possible to produce surface-metallized polyester molded articles with high productivity, uniformity, and good adhesion.

(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.

(Using a 11 volume resistivity electric washing machine, the sample was washed in a weak alkaline aqueous solution of 0.2% anionic activator for 2 hours, and then washed with water.

After drying, in the case of cloth, separate the threads.

In the case of filaments and spun yarns, the fibers are tied together into fiber bundles with a length of 103° and a fineness of 1000 denier, and then heated at 20°C and 40°C.
After conditioning the humidity at 1RH for 2 hours, the resistance of the sample was measured using an electrometer at an applied voltage of 1 mV.

Volume resistivity was calculated using the following formula.

(9X10”)・td [where, ρ: volume resistivity (Ω・crn), R: resistance (Ω), D: fineness (denier), t: fiber sample length (z)
, d: Sample density (11/ertl). ]
(2) Surface resistance The surface metallized molded product is placed in a room with humidity controlled at 20°C and 401RH.
It was left in the sun, the contact pressure of the electrodes was 1f71t5Ifl+, the distance between the two electrodes was 10crn, the front and back screens were sandwiched, and the terminals of an electrometer were connected to the terminals, and the resistance was measured with the electrometer. The measured value was converted to 1α per surface resistance.

(Volume specific resistance after 31120 bending friction Wash the sample in a weak alkaline aqueous solution of 0.2% anionic activator for 2 hours using an electric washing machine, wash with water, dry, and in the case of cloth, break the threads once. After that.

In the case of filaments, they were passed through a full comb at a bending angle of After leaving it at 401RH for 2 days, apply a voltage of 1 mV to the sample/rS using an electrometer.
la 80 ki ← - 慴Ito Reisha --
Ite autopsy = resistance was calculated.

(4) Thickness of plated part Average value of thickness of plated part and its variation σ. -4 was determined from electron micrographs of five arbitrary locations on the cross section of the fiber.

Example 1 A polyester tack consisting of polyester filaments of 75 denier/36 filaments and 50 denier/24 filaments was used, passed through a neutral detergent bath at 60° C., washed and subjected to normal degreasing treatment.

Passed through a 20% by weight aqueous sodium hydroxide solution (liquid temperature 90°C) for 5 minutes, passed through running water, washed with water, passed through an IN-hydrochloric acid aqueous solution at 30°C for 10 minutes, Subsequently, the pressure was reduced to 100 mHg, and sensitization treatment N containing 5% by weight stannous chloride-hydrochloric acid acidic solution (bath temperature 30°C
) was immersed for 10 minutes, washed thoroughly under running water, and then passed through an activation bath (bath temperature 70°C) containing an aqueous solution with a palladium concentration of 2 ppm for 10 minutes, washed with water, and heated to 75°C. The fabric was passed through a nickel-hypophosphite chemical plating bath for 3 minutes to obtain a conductive polyester fiber cloth with excellent metallic luster and no uneven metal coating. Its performance was measured and the results are shown in Table 1.

As is clear from Table 1, the conductive polyester fiber of the present invention has a volume resistivity of 9.3×10 (Ω・cfR).
It was found that this is a polyester cloth with excellent conductivity. 120 Volume resistivity after bending friction treatment is 7.8XI
There is no change in conductivity at all at O (Ω・α).

The conductive polyester fiber had a metal coating with extremely good adhesion and was resistant to impacts such as bending friction.

Example 2 A polyester multifilament yarn of 75 tenier/36 filaments was used, the dipping time was 5 minutes in diluted hydrochloric acid, and the sensitization treatment was carried out by immersing it in diluted hydrochloric acid for 5 minutes at a reduced pressure of 50 μHg. Processing was performed using the same processing method as in Example 1 to obtain nine conductive polyester fibers of the present invention. Its performance was measured and the results are shown in the i@1 table. As is clear from Table 1.

The conductive polyester fiber according to the present invention had excellent conductivity and durability.

Example 3 Using polyester spun yarn, the degree of vacuum during sensitization treatment was 20
Two surface metallized polyester fibers of the present invention were obtained by processing in the same manner as in Example 1, except that the concentration was 0 ■Hg. Its performance was measured and the results are shown in Table 1. As is clear from Table 1, the conductive polyester fibers according to the present invention had excellent conductivity and durability.

Example 4 Using a polyester film with a thickness of 2 microns,
Table 1 shows the results of processing in the same manner as in Example 1, except that the sample was treated with an alkali using a hydroxide solution (liquid temperature: 70° C.) and the sensitization treatment was carried out at normal pressure.

Example 5 Sensitization treatment The same procedure as in Example 2 was carried out except that the treatment was carried out at normal pressure.
Conductive polyester filaments listed in Table 1 were obtained.

The metal coating on the filament was uniform and had good adhesion.

Comparative Example 1 In Example 1, after the alkali treatment and water washing, sensitization treatment was performed by immersing the sample in a dilute hydrochloric acid solution for a long time for 120 minutes under normal pressure without immersing it. Thereafter, activation treatment, washing with water, and immersion in a chemical plating bath were sequentially performed to obtain the surface metallized polyester fibers listed in Table 1. Although the filament was subjected to sensitization treatment for a long time, the adhesion of the metal coating was weakened, resulting in poor operability and unsatisfactory uniformity of the metal coating.

Comparative example 2 Do not treat with dilute hydrochloric acid solution after alkaline treatment.

Conductive polyester filament cloths listed in Table 1 were obtained in the same manner as in Example 1, except that the cloths were held in running water for 10 minutes and thoroughly washed with water. The filament had insufficient metal coating and poor conductivity.

Comparative Example 3 Conductive polyester spun yarns listed in Table 1 were obtained in the same manner as in Example 3, except that the yarns were not immersed in a dilute hydrochloric acid solution after the alkali treatment. The amount of metal coating formed on the spun yarn is insufficient, and the thickness of the metal coating is uneven.

The conductivity was poor.

(Effect) By treating the alkaline components remaining on the surface of the substrate after alkali treatment with an acidic solution, it is possible to prevent the formation of precipitates in weakly alkaline to neutral conditions of metals used in sensitization treatment, and to achieve uniform and strong adhesion. A metal film was formed.

The surface-metallized polyester molded product according to the present invention is suitable for various uses requiring conductivity, electromagnetic shielding materials, etc., and can also be used for antistatic purposes by mixing hydrophobic fibers into textile products.

Claims (1)

[Claims] (1) After applying alkali treatment to the polyester molded product,
A method for producing a surface metallized polyester molded article, which comprises treating the article with an acidic solution, followed by sensitization treatment and activation treatment, and then applying chemical plating.