JP2011127152A - Electroless plating method to polystyrene-based resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To considerably reduce the load on the environment by not using any hexavalent chromium or potassium permanganate which has been used in the etching process, and to enhance the adhesiveness of a plating coating film applied on a polystyrene-based resin. <P>SOLUTION: In an electroless plating method to a polystyrene-based resin in which the polystyrene-based resin is subjected to the resin plating, the polystyrene-based resin or the polystyrene-based resin mainly consisting of styrene component is subjected to the ozone water treatment using ozone aqueous solution to the polystyrene-based resin as the etching treatment. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electroless plating technology for plating a synthetic resin, and in particular, a polystyrene resin capable of extremely reducing environmental load and capable of applying a highly adhesive plating film to a polystyrene resin. The present invention relates to an electroless plating method.

  Synthetic resin decorative plating is lightweight and has a metallic luster appearance, so it is used in a wide range of applications such as automotive parts and faucet fittings. Among them, ABS resin has high workability and is excellent in impact resistance and bending fatigue. ABS resin is the most versatile synthetic resin.

  An example of a process for performing an electroless plating process on such a synthetic resin molded product is shown in the flowchart of FIG. In this processing method, the resin molded product (ABS resin) is first subjected to pre-treatment degreasing process, etching process, catalyst process, accelerator process, and the like. Next, an electroless nickel plating step and an electroplating step are sequentially performed.

The pre-treatment degreasing step is a step of removing oil, fingerprints and the like adhering to the surface of the synthetic resin molded product. Further, this is a process for improving the wettability during the etching process of the next process.
The etching step is a step in which the surface of the resin molded product is chemically roughened (uneven) with chromic acid / sulfuric acid or the like, and then the remaining chromium compound is removed with hydrochloric acid or the like.
The catalyst process is a process of adsorbing a catalyst metal that becomes the core of electroless plating. In general, a Pd—Sn complex or the like is used.
The accelerator process is a process in which tin salt is dissolved and metal palladium is generated by an oxidation-reduction reaction.

Next, in the electroless nickel plating process, nickel ions are reduced by the electrons released when the reducing agent in the plating solution is oxidized on the catalytically active palladium surface, and a plating film is formed on the surface of the resin molded product. It is a process to make.
In the electroplating process, since the surface of the resin molded product is metalized and can be energized, it is a process of finishing by performing a metal plating process by bright nickel plating or copper sulfate plating by electrolysis.

As described above, environmental pollution due to treatment of these waste liquids using chromic acid or sulfuric acid in the etching process has become a problem in recent years. In order to deal with such problems, Patent Documents 1, 2, and 3 propose various technologies for pretreating the surface of a resin molded product (substrate) by using ozone gas or ozone water instead of chromic acid or sulfuric acid. Has been. For example, Japanese Patent Laid-Open No. 1-92377, “Pretreatment Method of Electroless Plating Material” of Patent Document 1, uses a synthetic resin molded article as a raw material and deposits a metal film on the surface of the raw material by chemical treatment. In the method, prior to electroless plating, a pretreatment method is proposed in which the material is heated and treated with ozone gas.
JP-A-1-92377

Japanese Patent Application Laid-Open No. 2001-131759 of “Patent Document 2” describes a pretreatment method for electroless plating in which a metal film is deposited on a surface of a plastic molded article by chemical treatment. As a treatment method, a pretreatment method for electroless plating in which a surface of the plastic molded article is roughened using an aqueous hydrogen carbonate compound solution and ozone has been proposed.
JP 2001-131759 A

Japanese Patent Application Laid-Open No. 2002-309377 of “Patent Document 3” discloses a “pretreatment method of an electroless plating material” in which a resin having an unsaturated bond is used as a plating material and the plating material is brought into contact with a first solution containing ozone. Before an electroless plating material for performing a treatment step and a second treatment step in which a second solution containing at least one of an anionic surfactant and a nonionic surfactant and an alkali component is brought into contact with the plating material. A processing method has been proposed.
JP 2002-309377 A

  As described above, since ozone is decomposed into oxygen in a natural state, there is a characteristic that it is possible to almost solve the problem of environmental pollution as in the case of using chromic acid, sulfuric acid or the like in the etching process as in the past.

  However, the techniques proposed in these documents 1, 2 and 3 are all related only to the examples targeting ABS resin. The effect with polystyrene resin is not disclosed. Polystyrene resin is a material that has low specific gravity, is inexpensive, has high dimensional stability, and is increasingly used as a resin molded product.

  Accordingly, the inventors of the present application have focused on the treatment with ozone for polystyrene resins and polystyrene resins, and have created an electroless plating treatment method through various experiments, measurements, and studies. Furthermore, it confirmed that adhesiveness with the plating film given to the polystyrene-type resin can be improved.

A method of pretreating a styrene resin with a permanganate aqueous solution is disclosed. Japanese Patent Application Laid-Open No. 2007-100194 “Pretreatment Method for Plating to Styrenic Resin Molded Body” of Japanese Patent Application Laid-Open No. 2007-100194 discloses an aromatic hydrocarbon which may have a lower alkyl group as a substituent and a lower alkanoyl group as a substituent A step of contacting an aqueous dispersion or aqueous solution containing at least one organic compound selected from the group consisting of di-lower alkyl ketones, higher alcohols, and di-lower alkyl ethers, which may have The step of bringing the resin molded body treated in the step into contact with an aqueous solution containing a permanganate, and the resin molded body treated in the step from the group consisting of an acid, a perchlorate and a peroxoacid salt Resin a polystyrene-based resin or a polystyrene-based alloy resin, including a step of contacting with an aqueous solution containing at least one selected component Pretreatment method for plating against min to the resin molded body has been proposed.
JP 2007-100194 A

  However, in “Pretreatment Method for Plating to Styrenic Resin Molded Body” of Patent Document 4, after performing a swelling treatment with a specific organic compound-containing aqueous solution, an etching treatment with a permanganate aqueous solution and an inorganic acid or a specific Therefore, there has been a problem that the number of processing steps is increased.

  The present invention has been developed to solve such problems. That is, the object of the present invention is to reduce the burden on the environment by not using any hexavalent chromium or potassium permanganate that has been conventionally used in the etching process. Another object of the present invention is to provide a method for electroless plating of a polystyrene resin that can improve the adhesion of the plated film.

  The present invention relates to an electroless plating treatment method for a polystyrene resin in which a polystyrene resin is subjected to a resin plating treatment, and the polystyrene resin or the polystyrene resin having a styrene component as a main constituent component is etched as a polystyrene resin. It is characterized by being subjected to ozone water treatment using an ozone aqueous solution.

  Alternatively, the present invention is a method of electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin, and a polystyrene resin or a polystyrene resin in which a styrene component is a main constituent component is used as an etching process. Ozone is dissolved in water having a temperature of 5 to 50 ° C. to produce an ozone aqueous solution having an ozone concentration of 10 to 60 ppm, and a polystyrene resin is immersed in the ozone aqueous solution to perform ozone water treatment. .

  Alternatively, the present invention is a method of electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin, and a polystyrene resin or a polystyrene resin in which a styrene component is a main constituent component is used as an etching process. Water ozone at a temperature of 5 to 50 ° C. is dissolved to produce an ozone aqueous solution having an ozone concentration of 10 to 60 ppm, and this ozone aqueous solution is sprayed on a polystyrene resin for 3 to 12 minutes to perform ozone water treatment.

  Alternatively, the present invention is a method of electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin, and a polystyrene resin or a polystyrene resin in which a styrene component is a main constituent component is used as an etching process. While circulating water at a temperature of 5 to 50 ° C., ozone is dissolved therein to produce an ozone aqueous solution having an ozone concentration of 10 to 60 ppm, and a polystyrene resin is immersed in the ozone aqueous solution for 3 to 12 minutes. It is characterized by performing ozone water treatment.

  For example, the aqueous ozone solution can be generated using a non-porous membrane module.

It is possible to replace the polystyrene resin or a copolymer resin containing a styrene component as a main component with a resin that does not contain a rubbery polymer.
It is possible to replace the polystyrene resin or a copolymer resin whose main component is the styrene component with a resin having an aromatic vinyl compound content of 70 wt% or more.

  The polystyrene-based resin is not particularly limited as long as the surface is treated with the ozone or ozone water, and may be a resin that is usually used for daily necessities, toys, home appliances, OA equipment, automobile parts, and the like. Examples include general PS resin (Polystyrene), general-purpose polystyrene (GPPS), high-impact polystyrene (HIPS), syndiotactic polystyrene (SPS), and the like.

  As the polystyrene-based resin, a resin having a content of an aromatic vinyl compound in a copolymer resin in which a polystyrene resin or a styrene component is a main constituent component is 70% by weight or more is preferable. Also preferred is a resin that does not contain a rubbery polymer in a polystyrene resin or a copolymer resin in which a styrene component is the main constituent.

In the electroless plating treatment method of the present invention, ozone gas or an ozone aqueous solution is used.
Although it does not specifically limit as a density | concentration of ozone in the said ozone aqueous solution, The preferable minimum in normal temperature is 5 ppm, and a preferable upper limit is 60 ppm. If it is less than 5 ppm, the resin may not be sufficiently treated with ozone water no matter how long the treatment time is extended, and if it exceeds 60 ppm, it will be close to the saturated concentration and the dissolution efficiency will decrease. A more preferred lower limit is 10 ppm, and a more preferred upper limit is 50 ppm. However, this concentration range also changes with changes in temperature.

  Although it does not specifically limit as temperature which makes the said polystyrene-type resin and ozone or ozone aqueous solution contact, A preferable minimum is 5 degreeC and a preferable upper limit is 60 degreeC. If it is less than 5 ° C, the reaction rate becomes slow and the resin may not be sufficiently treated with ozone water. If it exceeds 60 ° C, it becomes difficult to dissolve ozone. A more preferable lower limit is 20 ° C., and a more preferable upper limit is 50 ° C.

  Although it does not specifically limit as time to make the said polystyrene-type resin and ozone or ozone aqueous solution contact, A preferable minimum is 1 minute and a preferable upper limit is 15 minutes. If it is less than 1 minute, the resin may not be sufficiently treated with ozone water, and if it exceeds 15 minutes, no further effect can be obtained. A more preferred lower limit is 2 minutes, and a more preferred upper limit is 10 minutes.

  The method of bringing the polystyrene resin into contact with ozone or an aqueous ozone solution is not particularly limited, and examples thereof include a method of preferably spraying an aqueous ozone solution onto the resin and a method of immersing the resin in the aqueous ozone solution.

Various additives may be added to the ozone aqueous solution. Specifically, a surfactant, an organic solvent, an acid and the like as described later are added.
A surfactant or an organic solvent has an effect of lowering the interfacial tension between the resin and ozone or an aqueous ozone solution, and efficiently bringing the ozone or ozone water into contact with the resin.
The acid has the effect of preventing the self-decomposition of ozone water by lowering the pH of the ozone aqueous solution, and as a result, increasing the concentration of ozone water.

  Specific examples of the surfactant include saturated aliphatic surfactants having no carbon-carbon double bond represented by the following general formula (1). In the formula, R is a hydrophobic group comprising a saturated hydrocarbon or a saturated halogenated carbon compound, n is an integer of 1 to 3, X is an ether group having no carbon-carbon double bond and an aromatic group, a hydroxyl group, an ester group, The hydrophilic group compound which has any one of a carboxyl group, a sulfone group, a sulfuric acid group, and an amino group is represented.

  The hydrophobic group (R) does not include unsaturated hydrocarbons or aromatic hydrocarbons. Although carbon number is not specifically limited, About 10-30 is preferable. Further, a plurality of hydrophobic groups (R) may be present in one molecule.

  Regarding specific examples of the surfactant, examples of the nonionic surfactant include polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, polyoxyethylene cetyl stearyl diether, other polyoxyethylene alkyl ethers, polyoxyethylene poly Examples include oxypropylene cetyl ether, polyoxyethylene polyoxypropylene decyl tetradecyl ether, polyoxypropylene stearyl ether, polyoxyethylene hydrogenated castor oil, and polyglycerin fatty acid ester.

  Examples of anionic surfactants include alkyl sulfates such as ammonium lauryl sulfate, ethanolamine lauryl sulfate, sodium lauryl sulfate, triethanolamine lauryl, polyoxyethylene lauryl ether triethanolamine sulfate, and polyoxyethylene alkyl ether. Polyoxyethylene alkyl sulfates such as sodium sulfate, polyoxyethylene alkyl ether sulfates such as sodium polyoxyethylene tridecyl ether acetate, N, such as lauroyl sarcosine triethanolamine, lauroyl methyl-sodium L-glutamate, sodium lauroyl methyl taurate -Acyl amino acid salts and the like. Examples of the salts include ammonium salts, sodium salts, potassium salts, and lithium salts that become water-soluble.

  Examples of the cationic surfactant include oleyldi (polyoxyethylene) methylammonium chloride, stearyldimethylbenzylammonium chloride, distearyldimethylammonium chloride, stearyltrimethylammonium chloride, stearyltri (polyoxyethylene) ammonium chloride, and chloride. Examples include polyoxypropylene methyl diethyl ammonium, myristyl dimethyl benzyl ammonium chloride, and lauryl trimethyl ammonium chloride.

Examples of the amphoteric surfactant include lauric acid amidopropyl betaine, lauric acid amidopropyl hydroxysulfobetaine, stearyl dihydroxyethyl betaine, and hydroxyalkylhydroxyethylmethylglycine.
These surfactants may be used alone or in combination of two or more.

  The surfactant is preferably one having excellent solubility with the ozone water, and one having an HLB value of 8 or more is preferably used. If it is less than 8, it does not disperse in water, and on the contrary, plating adhesion may not be good. A more preferred lower limit is 10. The HLB value is a numerical value used as an index representing the hydrophilicity and lipophilicity of the surfactant.

  Although it does not specifically limit as a density | concentration of the said surfactant in the said ozone aqueous solution, A preferable minimum is 0.001 weight% and a preferable upper limit is 1 weight%. If the amount is less than 0.001% by weight, a sufficient surfactant effect may not be obtained. If the amount exceeds 1% by weight, excessive foaming is caused by the surfactant itself. In some cases, sufficient contact cannot be obtained. A more preferred upper limit is 0.1% by weight.

  Although it does not specifically limit as an organic solvent, The thing excellent in the solubility with the said ozone water is preferable. Specific examples include alcohols such as methanol, ethanol and 2-propanol, ketones such as acetone and methyl ethyl ketone, ethers such as diethyl ether and ethylene glycol monoethyl ether, and esters such as methyl acetate and ether ether. These organic solvents may be used alone or in combination of two or more.

  Although it does not specifically limit as a density | concentration of the said organic solvent in the said ozone aqueous solution, A preferable minimum is 0.001 weight% and a preferable upper limit is 1 weight%.

Although it does not specifically limit as an acid, Specifically, a sulfuric acid, hydrochloric acid, nitric acid etc. are mentioned as an inorganic acid. Organic acids include oxalic acid, formic acid, citric acid, malic acid, acetic acid, succinic acid and the like.
The concentration of the acid to be added in the ozone aqueous solution is not particularly limited.

  A gas-liquid direct dissolution method is mentioned as a manufacturing method of the said ozone aqueous solution. Specifically, there are a method in which ozone gas is dissolved in water by a vacuum or an ejector, and a method in which ozone gas is dissolved in contact with water in a special packed tower.

  In addition, as a method for producing the ozone aqueous solution, a method using a non-porous membrane module is preferable, for example, a method in which water is set in an ozone water production apparatus incorporating a non-porous membrane module and ozone is dissolved in water. Etc. When such an apparatus is used, an ozone aqueous solution can be circulated and used. In addition, the order of adding the additives is when preparing ozone water and then adding the above-mentioned surfactant, organic solvent, or acid, or dissolving ozone in an aqueous solution containing the surfactant, organic solvent, and acid. There is. As a general method for producing an ozone aqueous solution, a method of dissolving ozone gas in water by an aeration method or a mixing method is known. However, in these methods, a large number of bubbles are present in the aqueous solution, and further bubbles are present in the aqueous solution to which the surfactant is added. Since these bubbles adhere to the surface of the polystyrene-based resin during the ozone water treatment, the ozone water treatment on the surface of the substrate is a non-uniform treatment.

  Although there is a method of dissolving ozone gas in water using a porous membrane, in this method, when a surfactant is added, the surfactant solution flows out from the micropores to the outside of the membrane due to a decrease in surface tension. Is not preferred.

  After the surface of the resin is treated using the electroless plating treatment method of the present invention, the resin surface is plated using a metal plating solution by a conventionally known method as shown in the flow chart of FIG.

  In the present invention, since no hexavalent chromium or potassium permanganate conventionally used in the etching process is used, waste liquid that pollutes the environment does not occur. Therefore, the load on the environment can be extremely reduced. Moreover, the adhesiveness of the plating film provided to the polystyrene resin can be improved.

It is process drawing which shows the electroless-plating processing method of the polystyrene-type resin of this invention. It is the graph which compared the plating adhesive force in various polystyrene resin at the time of implementation of the ozone water treatment plating of this invention by peeling strength. It is process drawing which shows the conventional electroless-plating processing method.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a process diagram showing an electroless plating method for polystyrene resin of the present invention.
In the method of electroless plating of polystyrene resin of the present invention, a polystyrene resin molded product is subjected to a pretreatment step S1 such as degreasing and an ozone water treatment step S2 as an etching treatment step instead of the conventional chromic acid etching treatment. Apply in order.

  Next, the catalyst process S3 and the accelerator process S4 are performed in order. The catalyst step S3 is a step of adsorbing a catalyst metal that becomes the core of electroless plating. For example, a Pd—Sn complex is used. The accelerator step S4 is a step in which tin salt is dissolved and metal palladium is generated by an oxidation-reduction reaction.

The electroless Ni plating step S5, the electrolytic Cu plating step S6, the water washing step S7, and the drying step S8 are sequentially performed to finish the plating process.
The electroless Ni plating step S5 is a step in which nickel ions are reduced by electrons released when the reducing agent in the plating solution is oxidized on the catalytically active palladium surface, thereby generating a plating film.
Finally, an electrolytic Cu plating step S6 is performed. In this electric Cu plating treatment step S6, since the surface is metallized and energization is possible, it can be finished by performing metal plating treatment by bright nickel plating or copper sulfate plating by electrolysis. Thereafter, the plating solution adhering to the surface of the resin molded product is washed away in the water washing step S7, and water is removed by drying in the drying step S8.

  In the electroless plating treatment method for polystyrene resin of Example 1, as ozone water treatment step S2, ozone is dissolved in water having a liquid temperature of 5 to 50 ° C. to produce an ozone aqueous solution having an ozone concentration of 10 to 60 ppm. . The generated ozone aqueous solution is treated by immersing a substrate made of polystyrene resin.

  Next, a catalyst process S3, an accelerator process S4, an electroless Ni plating process S5, and then an electrolytic Cu plating process S6 are sequentially performed to deposit copper plating on the surface of the base made of polystyrene resin.

  It was confirmed visually that the obtained Cu plating film had a metallic luster with a high design property.

  In the electroless plating treatment method of polystyrene resin of Example 2, as ozone water treatment step S2, ozone gas generated at 25 to 35 ° C. by an ozone gas generator in a container containing water at a liquid temperature of 20 to 30 ° C. Is supplied by an aeration method at a flow rate of 0.3 to 0.7 L / min to generate an ozone aqueous solution having an ozone concentration of 40 to 60 ppm. The obtained ozone aqueous solution is sprayed on a substrate made of polystyrene resin for 8 to 12 minutes using a spray nozzle.

  Next, in the same manner as in Example 1, the catalyst process S3, the accelerator process S4, the electroless Ni plating process S5, and then the electrolytic Cu plating process S6 are respectively performed in order, and the surface of the base made of polystyrene resin is coated with copper. Deposit plating.

  It was confirmed visually that the obtained Cu plating film had a metallic luster with a high design property.

  About the plating film formed by said method, peel strength measurement was performed and adhesiveness was evaluated. The results are shown in Table 1 below.

  In the electroless plating treatment method for polystyrene resin of Example 3, as the ozone water treatment step S2, using an ozone water production apparatus incorporating a non-porous membrane module, water having a liquid temperature of 30 to 40 ° C. is circulated. While circulating at a flow rate of 1.2 to 1.6 L / min, ozone is dissolved to produce an ozone aqueous solution having an ozone concentration of 20 to 40 ppm. This method can rapidly produce an aqueous ozone solution and can stabilize the concentration of ozone water. A substrate made of a polystyrene resin is immersed in the obtained aqueous ozone solution for 4 to 8 minutes for treatment.

  Next, similarly to Example 1 or 2, the catalyst surface S3, the accelerator step S4, the electroless Ni plating step S5, and then the electrolytic Cu plating step S6 are sequentially performed to form a substrate surface made of polystyrene resin. To deposit copper plating.

  It was confirmed visually that the obtained Cu plating film had a metallic luster with a high design property.

  Table 1 shows the results of measuring the peel strength and evaluating the adhesion of the plating film formed by the above method. As is clear from the above results, it can be seen that the plating treatment using the ozone treatment of the polystyrene resins of Examples 1, 2, and 3 is particularly effective for the polystyrene resin in terms of both appearance and peel strength and has high adhesion.

  As comparative examples, polyethylene terephthalate, polycarbonate, polyethylene, polyacetal, and polyphenylene sulfide were also tested. As shown in Table 1, the substrate made of these resins was treated in the same manner as in Example 3, and the appearance of the formed plating film having a high design metallic luster on the entire surface was observed, and Peel strength measurement was performed to evaluate adhesion. Neither was satisfactory in appearance and adhesion. In particular, plating did not deposit for polyethylene, polyacetal, and polyphenylene sulfide.

FIG. 2 is a graph showing plating adhesion in various PS resins when performing ozone water treatment plating.
From the results shown in this figure, it was found that there are resins suitable for ozone water treatment plating and resins not suitable for various PS resins of polystyrene type resin. General PS resin, SPS resin (crystallized polystyrene) and extrusion HIPS resin showed relatively high peeling strength. High gloss high impact HIPS and ultra high gloss HIPS were low values. Thus, in all the resins, the plating deposition was good. The ozone water treatment in the electroless plating treatment method of the present invention is suitable for PS resin.

  In addition, this invention is not limited to embodiment of the invention mentioned above, By using hexavalent chromium, potassium permanganate, etc. which were conventionally used in the etching process at all, an environmental load is reduced extremely. As long as it is a method that can further improve the adhesion of the plating film applied to the polystyrene-based resin, it is not limited to the configuration as shown in the illustrated process or processing method, and does not depart from the gist of the present invention. Of course, various changes can be made.

  The method of electroless plating of polystyrene resin of the present invention can be used for a wide range of polystyrene resins such as general PS resin, SPS resin, HIPS resin and the like.

Claims (8)

A method for electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin,
About polystyrene resin or polystyrene resin in which styrene component is the main constituent,
An electroless plating method for a polystyrene resin, wherein the polystyrene resin is subjected to an ozone water treatment using an aqueous ozone solution as an etching treatment. A method for electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin,
About polystyrene resin or polystyrene resin in which styrene component is the main constituent,
As an etching process, ozone is dissolved in water having a liquid temperature of 5 to 50 ° C. to produce an ozone aqueous solution having an ozone concentration of 10 to 60 ppm.
A method for electroless plating of a polystyrene resin, characterized in that a polystyrene resin is immersed in this aqueous ozone solution and subjected to ozone water treatment. A method for electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin,
About polystyrene resin or polystyrene resin in which styrene component is the main constituent,
As an etching process, ozone is dissolved in water having a liquid temperature of 5 to 50 ° C. to produce an ozone aqueous solution having an ozone concentration of 10 to 60 ppm.
A method for electroless plating of a polystyrene resin, wherein the ozone aqueous solution is sprayed on the polystyrene resin for 3 to 12 minutes to perform ozone water treatment. A method for electroless plating of a polystyrene resin in which a resin plating treatment is performed on a polystyrene resin,
About polystyrene resin or polystyrene resin in which styrene component is the main constituent,
As an etching process, while circulating water at a liquid temperature of 5 to 50 ° C., ozone is dissolved therein, and an ozone aqueous solution having an ozone concentration of 10 to 60 ppm is generated.
A method for electroless plating of a polystyrene resin, wherein the ozone resin is subjected to ozone water treatment by immersing the polystyrene resin in this ozone aqueous solution for 3 to 12 minutes.   5. The method for electroless plating of polystyrene-based resin according to claim 1, wherein the ozone aqueous solution is generated using a non-porous membrane module.   5. The method for electroless plating of polystyrene-based resin according to claim 1, wherein the ozone aqueous solution is generated using a gas-liquid direct dissolution method.   5. The method for electroless plating of polystyrene resin according to claim 1, wherein a rubbery polymer is contained in the polystyrene resin or the polystyrene resin in which the styrene component is a main component.   5. The electroless plating method according to claim 1, wherein a content of the styrene component in the polystyrene resin in which the polystyrene resin or the styrene component is a main constituent is 70% by weight or more. .

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