Plating method for insulating molded article and electroless plating Pd / Sn colloid catalyst solution used therefor

Abstract

To solve the problem in which: a Pd / Sn colloidal catalyst solution has been conventionally used in electroless plating, but the price of metal palladium Pd has markedly soared recently, and cost reduction must be achieved.SOLUTION: A Pd / Sn colloidal catalyst solution according to the present invention contains a trace quantity of an element belonging to Group 4 of the periodic table (preferably, in combination with an anionic surfactant), resulting in sufficient catalytic activity at low Pd concentration (for example, 15 mg / L). Preferably, the element belonging to Group 4 of the periodic table is zirconium, and preferably, the anionic surfactant is sodium dodecyl sulfate or polyoxyethylene alkyl ether sulfate.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for electroless plating an insulator molded article and a Pd / Sn colloid catalyst solution used therefor.

Background Art

[0002] Plastics used in ornaments, exterior parts, etc. include ABS resin, PC / ABS resin, etc. In the metal plating of these plastics, a catalyst solution in which Pd / Sn is colloidalized is used as a catalyst application step in the pretreatment. This catalyst solution is provided as a colloidal solution composed of a palladium salt, tin chloride, and hydrochloric acid, and is called a Pd / Sn colloid catalyst solution. The Pd / Sn colloid catalyst solution is used to adsorb Pd as a catalyst on the surface of an insulator such as an etched plastic, and to act as a reaction nucleus for electroless plating in a subsequent process. However, since the production volume of palladium (Pd) is small and the demand for it as a catalyst for automotive exhaust gas treatment has been increasing in recent years, the price of Pd / Sn colloid catalyst solution has also increased due to the soaring price.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The soaring price of such Pd / Sn colloid catalyst solution also contributes to the increase in the cost of the entire surface treatment by metal plating, and it is necessary to solve this problem. In the plating of general ABS resins, the palladium concentration in the Pd / Sn catalyst solution is often used at a concentration of 25 mg / L or higher. In plating, the consumption of palladium is high not only due to adsorption as a catalyst but also due to outflow to water washing during processes such as pumping to the next process. Although the palladium that has flowed out to the water washing process is recycled by recovery, there are still losses, so there are also issues in terms of the environment and cost. Suppressing the amount of palladium used in the Pd / Sn colloid catalyst solution is an urgent issue.

[0005] As one solution, to reduce the cost of the Pd / Sn catalyst solution, it is effective to use a lower Pd / Sn concentration. However, in such a case, it has an adverse effect on plating. As a countermeasure, it was effective to use a cation addition process for assisting catalyst adsorption as surface conditioning in the previous process, or a post-treatment agent that removes hexavalent chromium that acts as an adsorption inhibitor of palladium. In addition, measures such as physical factors (increasing liquid flow, stirring, temperature conditions, etc.) to improve the adsorption ability in the catalyst application process may be used, but it is not necessarily an effective method for many molded products.

Means for Solving the Problem

[0006] As a result of intensive research, the inventors of the present application have added and mixed a trace amount of an element belonging to Group 4 of the periodic table to the Pd / Sn colloid catalyst solution, And and by additionally adding a surfactant having an anionic property with an alkyl group having 6 to 16 carbon chains, they have succeeded in significantly reducing the palladium concentration in the conventional method. That is, the present invention is a plating method for an insulator molded product and a Pd / Sn colloid catalyst solution used therefor as described below. 〔1〕A plating method for an insulator molded product, characterized in that after forming a catalyst on the surface of the insulator molded product using a Pd / Sn colloid catalyst solution containing an element belonging to Group 4 of the periodic table in mg / L 10~1000 mg / L and an anionic surfactant having 6 to 16 carbon atoms in the alkyl group at 10 to 500 mg / L containing with a Pd content of 5 to 200 mg / L metal plating is then applied to the surface. [2] On the surface of the insulator molded article, (1) zirconium, (2) titanium or (3) an element belonging to Group 4 of the periodic table of any of hafnium at 10 to 1000 mg / L and sodium dodecyl sulfate or polyoxyethylene alkyl ether sulfate as an anionic surfactant at 10 to 500 mg / L containing with a Pd content of 5 to 200 mg / L After forming a catalyst using a Pd / Sn colloid catalyst solution, a metal plating is applied to the surface thereof. A plating method for an insulator molded article, characterized in that

[0007] [3] In a plating method for an insulator molded article, after forming a catalyst on the surface of the insulator molded article using a Pd / Sn colloid catalyst solution, a metal plating is applied to the surface thereof. The with a Pd content of 5 to 200 mg / L Pd / Sn colloid catalyst solution, wherein an element belonging to Group 4 of the periodic table is contained in the colloid catalyst solution in 10~1000 mg / L and an anionic surfactant having 6 to 16 carbon atoms in the alkyl group at 10 to 500 mg / L A Pd / Sn colloid catalyst solution for plating, characterized in that it is formed by containing [4] In a plating method for an insulator molded article, after forming a catalyst on the surface of the insulator molded article using a Pd / Sn colloid catalyst solution, a metal plating is applied to the surface thereof. The with a Pd content of 5 to 200 mg / L Pd / Sn colloid catalyst solution, wherein (1) zirconium, (2) titanium or (3) an element belonging to Group 4 of the periodic table of any of hafnium at 10 to 1000 mg / L and sodium dodecyl sulfate or polyoxyethylene alkyl ether sulfate as an anionic surfactant at 10 to 500 mg / L A Pd / Sn colloid catalyst solution for plating, characterized in that it is formed by containing

Effect of the Invention

[0008] According to the present invention, a catalyst solution having a palladium concentration significantly reduced compared to the concentration of a conventional Pd / Sn colloid catalyst solution can be used to perform good metal plating. Furthermore, the coating time of the metal in the chemical plating process can be shortened. For example, excellent metal plating can be performed even at a low palladium concentration of 15 mg / L, which was difficult to plate by the conventional method. Therefore, the consumption amount of palladium and working time can be reduced, and the problem of high cost can be solved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Mode for Carrying Out the Invention

[0010] The feature of the present invention is that a trace amount of an element belonging to Group 4 of the periodic table is added to a Pd / Sn colloid catalyst solution for metal plating (preferably, a specific anionic surfactant is further added). As a result, a catalyst solution with a palladium concentration significantly reduced compared to the concentration of the conventional Pd / Sn colloid catalyst solution (a concentration of about 1 / 3 to 1 / 4, for example, a concentration of 15 mg / L in terms of palladium concentration) can perform good metal plating. In addition, the Pd / Sn colloid catalyst solution of the present invention is obtained by adding and mixing hydrochloric acid to an aqueous solution of a palladium salt and tin chloride, as is well known. Specifically, it is a hydrochloric acid acidic solution containing a metal palladium concentration of 1 mg / L or more in the composition and a tin chloride concentration of 0.4 g / L to 500 g / L. The conventional palladium concentration is often used at about 25 mg / L or more of palladium in the working solution. However, according to the present invention, the palladium concentration of the Pd / Sn colloid catalyst solution can obtain good results at a concentration of 1 mg / L or more, preferably 5 mg / L or more, more preferably 10 mg / L or more, and particularly preferably 15 mg / L or more. Although it is also possible to use it at a high concentration, generally it is used at a concentration of 200 mg / L or less from the viewpoints of cost and the like.

[0011] The Pd / Sn colloid catalyst solution of the present invention contains 1 to 10000 mg / L of an element belonging to Group 4 of the periodic table in the composition. Preferably, a range of 10 to 1000 mg / L is good. As the element belonging to Group 4 of the periodic table, (1) zirconium, (2) titanium, or (3) hafnium, etc. can be used. These metal elements can be used as chlorides, nitrates, acid chloride compounds, hydroxides, etc. In the research stage, the inventors have found that, in addition to adding trace amounts of elements belonging to Group 4 of the periodic table, the addition and combined use of an anionic surfactant can particularly improve the wettability of PC / ABS resins. Anionic surfactants with a carbon chain length of 6 to 16 in the alkyl group can be used. Common ones include sodium dodecyl sulfate, polyoxyethylene alkyl ether sulfates (C6·C16), etc. The concentration ranges from 1 to 2000 mg / L, preferably 10 to 500 mg / L.

[0012] The thus-prepared Pd / Sn catalyst solution can be used in the pretreatment process of resin plating. In general resin plating, after the surface is roughened (etched) with a chromic acid-sulfuric acid solution, a catalyst application step is performed with a Pd / Sn catalyst solution or a palladium hydrochloric acid acidic solution. However, the Pd / Sn colloidal catalyst solution according to the present invention can adopt methods such as etching with permanganate, etching with an oxidizing agent, surface roughening by UV, and roughening of the resin by electrolyzed oxidized water.

[0013] The Pd / Sn catalyst solution can also be used for non-conductive materials (insulators) such as ABS resin, PC / ABS resin, other resins, ceramics, and glass. In such cases, optimization of the etching and electroless plating conditions is required depending on the type of resin, etc.

[0014] Existing processes can be utilized for the recovery of palladium from the catalyst solution according to the present invention, so the reuse of metals by palladium recovery is also easy. The same applies to the washing water in the next step. Since the resin has no conductivity, electroless plating treatment, also generally called chemical plating, is performed to impart conductivity. The catalyst application according to the present invention is not limited to the commonly used electroless nickel plating, and can correspond to various electroless platings using palladium as a catalyst nucleus, such as electroless copper plating.

[0015] The plated product thus produced can be subjected to electroplating or other surface treatments in the same manner as conventional plated products, and can be handled in the same way as products plated with the currently commonly used Pd / Sn catalyst solution. Therefore, the present invention can be incorporated as a catalyst-imparting step into the general plating process steps for ABS resin and PC / ABS resin. By changing the catalyst-imparting step of the resin plating line in operation to the catalyst solution according to the present invention, the overall cost of the process can be reduced.

[0016] In the preparation of the Pd / Sn colloid catalyst solution of the present invention, it is generally prepared by reacting under hydrochloric acid acidity. That is, a Pd / Sn colloid catalyst solution is prepared by mixing a palladium chloride solution and a tin chloride solution under hydrochloric acid acidity, and various components are added with dilute hydrochloric acid at a predetermined concentration and diluted to a predetermined concentration for implementation.

Example

[0017] Next, examples of the present invention will be described.

Example

[0018] First, a solution was prepared with the metal palladium concentration in the catalyst solution set at 15 mg / L, adding zirconium oxychloride equivalent to 50 mg / L as Zr, and further adding 20 mg / L of sodium dodecyl sulfate. Note that zirconium oxychloride used "zirconium oxychloride" (trade name: octahydrate of zirconium oxychloride manufactured by Daiichi Rare Element Chemical Industry Co., Ltd. ZrOCl 2 ·8H 2 O ).

Example

[0019] In the same manner as the method shown in Example 1, a solution was prepared with the metal palladium concentration in the catalyst solution set at 15 mg / L, adding zirconium oxychloride equivalent to 50 mg / L as Zr and 20 mg / L of sodium polyoxyethylene alkyl ether sulfate with an alkyl group carbon chain number of 8.

Example

[0020] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 50 mg / L equivalent of zirconium oxynitrate as Zr and 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 6 carbon atoms in the carbon chain. Note that as the zirconium oxynitrate, "Zircozol ZN" (trade name: manufactured by Daiichi Rare Element Chemical Industry Co., Ltd., ZrO(NO2)2) was used.

Example

[0021] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 50 mg / L equivalent of zirconium oxychloride as Zr and 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 16 carbon atoms in the carbon chain. 〔Reference Example 1〕

Example

[0022] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 50 mg / L equivalent of zirconium oxychloride as Zr. 〔Reference Example 2〕

Example

[0023] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 50 mg / L equivalent of zirconium oxynitrate as Zr. 〔Reference Example 3〕

Example

[0024] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared in which titanium chloride was added in an amount equivalent to 50 mg / L as Ti. 〔Reference Example 4〕

Example

[0025] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared in which titanium chloride was added in an amount equivalent to 100 mg / L as Ti. 〔Reference Example 5〕

Example

[0026] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared in which titanium tetranitrate was added in an amount equivalent to 50 mg / L as Ti. 〔Reference Example 6〕

Example

[0027] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared in which hafnium oxide was added in an amount of 5 mg / L as Hf. 〔Reference Example 7〕

Example

[0028] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared in which zirconium oxychloride was added in an amount equivalent to 100 mg / L as Zr. 〔Reference Example 8〕

Example

[0029] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was set to 15 mg / L, and a solution was prepared in which zirconium oxychloride was added in an amount of 1000 mg / L as Zr.

Example

[0030] In the same manner as in Example 1, a solution was prepared such that the concentration of metallic palladium in the catalyst solution was 15 mg / L, zirconium oxychloride was 50 mg / L as Zr, and sodium polyoxyethylene alkyl ether sulfate with a carbon chain number of 12 in the alkyl group was added at 20 mg / L.

Example

[0031] In the same manner as in Example 1, a solution was prepared such that the concentration of metallic palladium in the catalyst solution was 10 mg / L, zirconium oxychloride was 50 mg / L as Zr, and sodium polyoxyethylene alkyl ether sulfate with a carbon chain number of 8 in the alkyl group was added at 20 mg / L.

Example

[0032] In the same manner as in Example 1, a solution was prepared such that the concentration of metallic palladium in the catalyst solution was 10 mg / L, zirconium oxynitrate was 50 mg / L as Zr, and sodium polyoxyethylene alkyl ether sulfate with a carbon chain number of 8 in the alkyl group was added at 20 mg / L.

Example

[0033] In the same manner as in Example 1, a solution was prepared such that the concentration of metallic palladium in the catalyst solution was 5 mg / L, zirconium oxychloride was 50 mg / L as Zr, and sodium polyoxyethylene alkyl ether sulfate with a carbon chain number of 8 in the alkyl group was added at 20 mg / L.

Example

[0034] In the same manner as in Example 1, a solution was prepared such that the concentration of metallic palladium in the catalyst solution was 5 mg / L, zirconium oxynitrate was 50 mg / L as Zr, and sodium polyoxyethylene alkyl ether sulfate with a carbon chain number of 8 in the alkyl group was added at 20 mg / L.

Example

[0035] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 10 mg / L, 100 mg / L of zirconium oxychloride as Zr, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms in the carbon chain.

Example

[0036] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 10 mg / L, 100 mg / L of zirconium oxynitrate as Zr, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms in the carbon chain. 〔Reference Example 9〕

Example

[0037] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 1 mg / L, 50 mg / L of zirconium oxychloride as Zr, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms in the carbon chain.

Example

[0038] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 30 mg / L, 50 mg / L of zirconium oxychloride as Zr, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms in the carbon chain.

Example

[0039] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 60 mg / L, 50 mg / L of zirconium oxychloride as Zr, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms in the carbon chain. Comparative Example 1

[0040] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, 0.5 mg / L of zirconium oxychloride as Zr, and a solution was prepared by adding 50 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms. Comparative Example 2

[0041] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, 0.5 mg / L of zirconium oxynitrate as Zr, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms. Comparative Example 3

[0042] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 12 carbon atoms. Comparative Example 4

[0043] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms. Comparative Example 5

[0044] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 20 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 4 carbon atoms. Comparative Example 6

[0045] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 100 mg / L of sodium polyoxyethylene alkyl ether sulfate having an alkyl group with 8 carbon atoms. Comparative Example 7

[0046] In the same manner as the method shown in Example 1, the concentration of palladium metal in the catalyst solution was set to 15 mg / L, and a solution was prepared by adding 10 mg / L of hexadecyltrimethylammonium chloride, a cationic surfactant. Comparative Example 8

[0047] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 15 mg / L, and a solution was prepared in which 20 mg / L of polyoxyethylene alkyl ether having 12 carbon atoms in the alkyl group was added as a nonionic surfactant. Comparative Example 9

[0048] In the same manner as the method shown in Example 1, the concentration of metallic palladium in the catalyst solution was made 15 mg / L, 50 mg / L of zirconium oxychloride as Zr was added, and a solution was prepared in which 50 mg / L of polyoxyethylene alkyl ether having 8 carbon atoms in the alkyl group was added as a nonionic surfactant. Comparative Example 10

[0049] In the same manner as the method shown in Example 1, a solution having a metallic palladium concentration of 10 mg / L in the catalyst solution was prepared. Comparative Example 11

[0050] In the same manner as the method shown in Example 1, a solution having a metallic palladium concentration of 15 mg / L in the catalyst solution was prepared. Comparative Example 12

[0051] In the same manner as the method shown in Example 1, a solution having a metallic palladium concentration of 30 mg / L in the catalyst solution was prepared. Comparative Example 13

[0052] In the same manner as the method shown in Example 1, a solution having a metallic palladium concentration of 60 mg / L in the catalyst solution was prepared.

[0053] Next, the above Examples and Comparative Examples are evaluated and examined. Evaluation by electroless plating Evaluation was performed from the deposition property and uniformity of plating according to the following conditions and evaluation methods. Materials: ABS resin (UMG ABS·3001M) and PC / ABS resin (UMG alloy·TC-37M) Size: 5 cm × 10 cm × 4 mm thickness: Test piece Evaluation (1) Measurement of palladium adsorption amount after catalyst application / activation process treatment (Table 2) Immerse the T.P. after catalyst application treatment and activation treatment in 50% aqua regia, The amount of palladium adsorbed on the surface was measured by atomic absorption spectrometry. Evaluation (2) Deposition property and uniformity of electroless nickel plating (Table 3) Deposition property: The time until the electroless nickel plating uniformly adheres to the surface was measured to evaluate the effectiveness of the catalyst. Uniformity: The uniformity of the appearance after the plating treatment was evaluated. Figure 1, Figure 2 is a photograph of an evaluation example showing the appearance of the state where the electroless nickel plating adheres to the surface of the test piece. Figure 1 is ABS resin, Figure 2 shows the case of PC / ABS resin.

[0054] The plating process is as shown in Table 1. It is a general plating process for ABS resin and PC / ABS resin. The chemicals used in each process were dissolved and diluted with water for bath preparation. Also, a water washing process was inserted between each process, except for the process between the preliminary immersion and catalyst application.

Table 1

[0055] "CP conditioner #2" (manufactured by Kizai Co., Ltd.) used in the degreasing process of Process 1 contains a surfactant and has the function of removing molding scraps and oil stains adhering to the resin surface. It removes the stains adhering to the resin surface during molding and maintains a clean resin surface.

[0056] Process 2 is an etching process using commonly used hexavalent chromic acid. By dissolving the butadiene resin contained in the resin, the surface is roughened, aiming to maintain the adhesion between the resin and the plating by anchor bonding.

[0057] Since the hexavalent chromium adsorbed on the resin surface by etching has strong oxidizing properties, if it is brought into the subsequent process, it will have adverse effects such as inhibiting the adsorption of the catalyst and the deposition of electroless plating. Therefore, in the neutralization process of Process 3, the surface hexavalent chromium is washed and reductively removed.

[0058] The Pd / Sn colloidal catalyst used for catalyst application decomposes the colloid by oxidation. In addition to the introduction of hexavalent chromium, stirring by air and the introduction of a large amount of water are factors that destabilize the colloid. Therefore, the preliminary immersion (step 4), which is the pre-step of catalyst application, replaces the water adhering to the surface with dilute hydrochloric acid and immerses it directly into the catalyst application step, thereby playing a role in reducing the introduction of water into catalyst application.

[0059] The catalyst application step of step 5 is an important step of the present invention and is a step of adsorbing the Pd / Sn colloidal catalyst on the resin surface.

[0060] Pd / Sn colloid is adsorbed on the surface by the catalyst application step. Since Sn adsorbed on the surface becomes a poison catalyst in the electroless nickel plating solution, Sn is removed by the activation step (step 6). In addition to hydrochloric acid, sulfuric acid, reducing agents, etc. may be used in combination for activation, but generally hydrochloric acid is used. In the activation step, in addition to the removal of Sn, the activation of palladium on the surface is performed. In the present invention, in addition to hydrochloric acid and sulfuric acid, other methods can also be used, but for evaluation, an activation solution of hydrochloric acid that is generally used is used.

[0061] In the activation step, dissolution (desorption) of palladium on the surface also occurs due to the acid. When the adsorbed Pd / Sn colloid is unstable, the desorption of Pd after activation increases, and when the adsorbed amount of Pd is small, the precipitation property and uniformity in electroless nickel plating deteriorate. The adsorbed amount of Pd after activation affects the result of the next electroless plating step.

[0062] The resin thus treated is subjected to nickel plating by electroless nickel plating (reduction reaction of nickel ions by sodium hypophosphite) with the palladium adsorbed on the surface as the starting point of the reaction. When nickel metal is plated on the surface, the reduction of nickel proceeds by the autocatalytic reaction of nickel, and the resin surface is coated with conductive nickel plating.

[0063] In this study, "Nikko 8K01" (manufactured by Kizai Co., Ltd.) was used for electroless nickel plating. This is a commonly used electroless nickel plating solution.

[0064] For electroless nickel plating, palladium adsorbed on the resin surface serves as a catalyst for deposition on the surface. Therefore, sufficient palladium must be adsorbed after the catalyst application step and after the activation step. The palladium adsorption amount after each step was measured and evaluated.

[0065] The evaluation of electroless nickel plating was carried out from two aspects: depositability (initial deposition) and uniformity (uniformity of appearance after 7 minutes of plating). Resin plating needs to cover the entire surface of the object to obtain conductivity on the resin surface. If either the depositability or the uniformity is poor, non-deposition or poor appearance may occur in the subsequent electroplating process, so these are important performance aspects. It is desirable for the depositability to be faster because the faster the initial depositability of the plating, the better the plating uniformity and the risk of non-deposition can be reduced.

[0066] Table 2 shows the measurement results of the adsorption amount of Pd on ABS resin and PC / ABS resin.

[0067] Judging from the results shown in Table 2, the palladium adsorption amount on ABS resin shows a tendency to depend on the concentration in the case of no addition (comparative example). By adding elements belonging to Group 4 of the periodic table at a palladium concentration of 15 mg / L, which is the target concentration of the present invention, the adsorption amount showed a tendency to increase. The adsorption amount on PC / ABS resin shows a tendency to be slightly smaller than that on ABS resin.

[0068] The catalyst solution of the comparative example also shows a tendency to depend on the palladium concentration, showing the minimum value at 10 mg / L, but the adsorption ability shows a tendency to improve by adding elements belonging to Group 4 of the periodic table. The addition of surfactant has little effect on the adsorption amount.

Table 2

[0069] The deposition property and uniformity of electroless nickel plating on ABS resin are shown in Table 3. In addition, Fig. 1 shows the adsorption amount of palladium on ABS resin and the evaluation of the surrounding of electroless nickel plating.

[0070] Table to 3 As shown, the plating deposition property in the ABS resin showed that the comparative example solution could not achieve deposition at a palladium concentration of 15 mg / L or less. As shown in the examples, the addition of elements belonging to Group 4 of the periodic table and The addition of an anionic surfactant improved the plating deposition property and showed the result of shortening the coating time. The addition of these components was effective in improving the deposition property and uniformity even in a lower concentration range such as a palladium concentration of 5 mg / L and 10 mg / L. This effect was mainly due to the addition of elements belonging to Group 4 of the periodic table, and the result showed that the influence was small when only an anionic surfactant was added. The addition of a cationic surfactant showed the result of precipitation and decomposition in the catalyst solution. Also, the addition of a nonionic surfactant did not give an improvement tendency to the surrounding. [Table 3]

[0071] The deposition property and uniformity of electroless nickel plating on PC / ABS resin are shown in Table 4. Similar to the ABS resin, the addition of elements belonging to Group 4 of the periodic table of electroless nickel plating showed an improved deposition property compared to no addition.

[0072] The addition of various anionic surfactants shows the result of improving the wettability to PC / ABS resin. This effect shows a tendency of synergistic action and improved precipitation property by the addition of elements belonging to Group 4 of the periodic table. Similar to the case of ABS resin, even when the palladium concentration is as low as 5 mg / L or 10 mg / L, an improvement in precipitation property can be observed. However, considering the uniformity after plating, it is considered desirable to use it at a concentration of 15 mg / L or more.

[0073] Comparative Example 5 is a case with a short carbon chain length, but its effectiveness for plating is not recognized. Also, as shown in Comparative Examples 8 and 9, nonionic surfactants tend to deteriorate the precipitation property of PC / ABS.

Table 4

[0074] From the above results, the present invention was able to establish good plating precipitation property and uniformity for ABS resin and PC / ABS resin by the addition of elements belonging to Group 4 of the periodic table. Particularly for PC / ABS resin, further improvement in precipitation property could be obtained by the addition of an anionic surfactant with the carbon chain length of the alkyl group being between 6 and 16.

[0075] An ordinary Pd / Sn colloid catalyst solution requires a palladium concentration of 60 mg / L to obtain a good appearance after plating. However, the Pd / Sn colloid catalyst solution according to the present invention can be used at a low concentration of 15 mg / L, and good plating precipitation property and uniformity can be obtained. A summary of the evaluation of the above results is shown in Table 5.

Table 5

[0076] Using the catalyst solution at a low concentration reduces the amount of palladium adsorbed on the material, so that not only can the consumption amount by plating be suppressed, but also the liquid extraction by the product and the loss of palladium by washing can be reduced, making cost reduction possible.

[0077] These effects can be applied in existing plating processes. It has been shown that by simply replacing the catalyst application step in a general plating process with the present invention, the concentration of palladium can be reduced and the cost can be lowered.

Industrial Applicability

[0078] The Pd / Sn colloid catalyst solution of the present invention can be used in a general electroless plating process for resins. In addition to electroless nickel plating (chemical nickel plating), it can be used in various electroless plating processes such as electroless copper plating (chemical copper plating).

Claims

1. A plating method for an insulating molded article, comprising: after forming a catalyst using a Pd / Sn colloidal catalyst solution containing an element belonging to Group 4 of the periodic table at 10 to 1000 mg / L and an anionic surfactant having 6 to 16 carbon atoms in the alkyl group at 10 to 500 mg / L, with a Pd content of 5 to 200 mg / L, applying a metal plating to the surface thereof.

2. A plating method for an insulating molded article, comprising: after forming a catalyst using a Pd / Sn colloidal catalyst solution containing an element belonging to Group 4 of the periodic table, which is any one of (1) zirconium, (2) titanium, or (3) hafnium, at 10 to 1000 mg / L and sodium dodecyl sulfate or polyoxyethylene alkyl ether sulfate as an anionic surfactant at 10 to 500 mg / L, with a Pd content of 5 to 200 mg / L, applying a metal plating to the surface thereof.

3. A Pd / Sn colloidal catalyst solution for plating, having a Pd content of 5 to 200 mg / L, which is used in a plating method for an insulating molded article, comprising: after forming a catalyst using a Pd / Sn colloidal catalyst solution on the surface of the insulating molded article, applying a metal plating to the surface thereof, and the colloidal catalyst solution contains an element belonging to Group 4 of the periodic table at 10 to 1000 mg / L and an anionic surfactant having 6 to 16 carbon atoms in the alkyl group at 10 to 500 mg / L.

4. A Pd / Sn colloidal catalyst solution for plating, having a Pd content of 5 to 200 mg / L, which is used in a plating method for an insulating molded article, comprising: after forming a catalyst using a Pd / Sn colloidal catalyst solution on the surface of the insulating molded article, applying a metal plating to the surface thereof, and the colloidal catalyst solution contains an element belonging to Group 4 of the periodic table, which is any one of (1) zirconium, (2) titanium, or (3) hafnium, at 10 to 1000 mg / L and sodium dodecyl sulfate or polyoxyethylene alkyl ether sulfate as an anionic surfactant at 10 to 500 mg / L.

Images