Electroless plating catalyst solution, electroless plating pretreatment method and electroless plating method

Abstract

To provide: an electroless plating catalyst solution for imparting a silver catalyst, capable of preventing metal silver from being deposited and excellent in solution stability; an electroless plating pretreatment method using the electroless plating catalyst solution excellent in solution stability; and an electroless plating method.SOLUTION: An electroless plating catalyst solution includes at least one kind of acid components selected from a group consisting of (A) silver nanoparticles, (B) a reducer, (C) oxo acid and organic acid has an oxidation reduction potential at 25°C of 0 mV or more and 400 mV or less.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a catalyst solution for electroless plating, a pretreatment method for electroless plating, and an electroless plating method.

Background Art

[0002] In recent years, electroless plating has been applied to resin materials in various fields. For example, for the purpose of lightening automobiles, resin molded bodies are used as automobile parts. For such purposes, as the resin molded body, for example, ABS resin, PC / ABS resin, PPE resin, polyamide resin, etc. are used, and plating such as copper and nickel is applied to impart a sense of luxury and aesthetics. Also, as a method of imparting conductivity to a resin substrate to form a conductor circuit, a method of forming a plating film such as copper or nickel on the resin substrate is also performed.

[0003] As a general method of forming a plating film on a resin material such as a resin substrate or a resin molded body, after roughening the surface of the resin material, neutralization and pre-dip are performed as necessary, and then an electroless plating catalyst is applied using a colloidal solution containing a tin compound and a palladium compound. Then, an activation treatment (accelerator treatment) for removing tin is performed, and a method of sequentially performing electroless plating and electroplating is performed.

[0004] However, in the above method, since expensive palladium is used to apply the catalyst, there is a problem that the cost increases. For this reason, it is required to use other metal catalysts other than palladium.

[0005] As a method of applying a metal catalyst other than palladium, it has been proposed to use a silver catalyst (see Patent Document 1). Patent Document 1 discloses that a silver colloid solution is produced as a pretreatment solution for applying a silver catalyst for electroless plating to produce a pretreatment solution for applying a silver catalyst for electroless plating.

[0006] However, in the pretreatment liquid produced by the method described in Patent Document 1, the redox potential has not been examined. In such a pretreatment liquid, aggregation of silver nanoparticles and ionization of silver nanoparticles occur, resulting in a problem of poor liquid stability.

[0007] Therefore, in the electroless plating catalyst liquid for imparting a silver catalyst, precipitation of metallic silver is suppressed, and development of an electroless plating catalyst liquid having excellent liquid stability is required.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] The present invention has been made in view of the above problems, and in an electroless plating catalyst liquid for imparting a silver catalyst, precipitation of metallic silver is suppressed, and an electroless plating catalyst liquid having excellent liquid stability, a pretreatment method for electroless plating using the electroless plating catalyst liquid having excellent liquid stability, and an electroless plating method are provided.

Means for Solving the Problems

[0010] As a result of intensive studies to achieve the above object, the present inventors have found that an electroless plating catalyst liquid containing (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids and having a redox potential at 25°C of 0 mV or more and 400 mV or less can achieve the above object, and have completed the present invention.

[0011] That is, the present invention relates to a composition for pretreatment of electroless plating, a pretreatment method, and an electroless plating method described below. 1. It contains (A) silver nanoparticles, (B) a reducing agent, and at least one acid component selected from the group consisting of (C) oxo acids and organic acids. It has a redox potential at 25 °C of 0 mV or more and 400 mV or less. An electroless plating catalyst solution characterized by the above. 2. The electroless plating catalyst solution according to item 1, wherein the average particle diameter of the silver nanoparticles is 1 to 200 nm. 3. The electroless plating catalyst solution according to item 1 or 2, wherein the content of the silver nanoparticles is 0.1 to 80% by mass with the electroless plating catalyst solution being 100% by mass. 4. The oxo acid is at least one selected from the group consisting of hypophosphorous acid, phosphorous acid, and thiosulfuric acid, and the organic acid is at least one selected from the group consisting of carboxylic acid and ascorbic acid. The electroless plating catalyst solution according to any one of items 1 to 3. 5. The reducing agent is at least one selected from the group consisting of dimethylamine borane and sodium borohydride. The electroless plating catalyst solution according to any one of items 1 to 4. 6. Further, it contains (D) a silver nanoparticle dispersant, and the (D) silver nanoparticle dispersant is polyoxyethylene alkyl ether phosphate. The electroless plating catalyst solution according to any one of items 1 to 5. 7. Further, it contains (E) a nonionic surfactant, and the nonionic surfactant is polyoxyalkylene alkyl ether. The electroless plating catalyst solution according to any one of items 1 to 6. 8. A pretreatment method for electroless plating of a resin material, (1) It has step 1 of bringing the surface to be treated of the resin material into contact with the electroless plating catalyst solution. The electroless plating catalyst solution contains (A) silver nanoparticles, (B) a reducing agent, and at least one acid component selected from the group consisting of (C) oxo acids and organic acids, and has a redox potential at 25 °C of 0 mV or more and 400 mV or less. A pretreatment method characterized by the above. 9. A electroless plating method for a resin material, comprising: (1) Step 1 of bringing the surface to be treated of the resin material into contact with a catalyst solution for electroless plating; and (2) Step 2 of bringing the surface to be treated of the resin material into contact with an electroless plating solution, wherein the catalyst solution for electroless plating contains (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and has a redox potential at 25°C of 0 mV or more and 400 mV or less. The electroless plating method is characterized by the above.

Effect of the Invention

[0012] The catalyst solution for electroless plating of the present invention is a catalyst solution for electroless plating for imparting a silver catalyst to an object to be treated, in which the precipitation of metallic silver is suppressed and the solution stability is excellent. Further, according to the pretreatment method for electroless plating and the electroless plating method of the present invention, since the catalyst solution for electroless plating of the present invention is used, the precipitation of metallic silver in the catalyst solution for electroless plating is suppressed and the solution stability is excellent, so that a silver catalyst can be easily imparted to an object to be treated.

Brief Description of the Drawings

[0013]

Figure 1

Modes for Carrying Out the Invention

[0014] Hereinafter, the present invention will be described in detail.

[0015] 1. Electroless plating catalyst solution The electroless plating catalyst solution of the present invention contains (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and is an electroless plating catalyst solution having a redox potential at 25 °C of 0 mV or more and 400 mV or less. The electroless plating catalyst solution of the present invention having the above characteristics, in addition to (A) silver nanoparticles and (B) a reducing agent that constitute a catalyst solution for imparting a silver catalyst, contains (C) at least one acid component selected from the group consisting of oxo acids and organic acids, whereby the redox potential can be adjusted to 0 mV or more and 400 mV or less, and the precipitation of metallic silver is suppressed. Further, since the aggregation of silver nanoparticles is suppressed because the redox potential of the electroless plating catalyst solution of the present invention is 0 mV or more at 25 °C, the precipitation of metallic silver is suppressed. Furthermore, since the ionization of silver nanoparticles is suppressed because the redox potential of the electroless plating catalyst solution of the present invention is 400 mV or less at 25 °C. That is, the electroless plating catalyst solution of the present invention contains (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and the redox potential at 25 °C is 0 mV or more and 400 mV or less, and thus the precipitation of metallic silver is suppressed and excellent liquid stability can be exhibited.

[0016] The electroless plating catalyst solution of the present invention has a redox potential (ORP) at 25 °C of 0 mV or more and 400 mV or less. If the lower limit of the redox potential is less than 0 mV, silver nanoparticles aggregate and the liquid stability decreases. Also, if the upper limit of the redox potential exceeds 400 mV, silver nanoparticles ionize and the liquid stability decreases. The redox potential is preferably 20 mV or more, more preferably 30 mV or more, and even more preferably 100 mV or more. Further, the acid value redox potential is preferably 350 mV or less, more preferably 300 mV or less.

[0017] In this specification, the measurement of the redox potential at 25 °C of the electroless plating catalyst solution is carried out by the measurement method described in the examples.

[0018] As a method for adjusting the redox potential, there is a method of adding an oxo acid and an organic acid. When the concentrations of the oxo acid and the organic acid are low, the redox potential becomes high, and when the concentrations of the oxo acid and the organic acid are high, the redox potential becomes low.

[0019] ((A) Silver nanoparticles) The electroless plating catalyst solution of the present invention contains (A) silver nanoparticles (hereinafter, also referred to as “component (A)”).

[0020] Component (A) is not particularly limited, and examples thereof include silver nanoparticles in which silver ions are generated as a silver source in the electroless plating catalyst solution of the present invention.

[0021] As the silver ions for generating component (A) in the electroless plating catalyst solution of the present invention, monovalent silver ions can be preferably used. The silver salt for imparting monovalent silver ions is not particularly limited as long as it can impart stable monovalent silver ions in the solution when dissolved in the electroless plating catalyst solution. Specifically, silver(I) sulfate, silver(I) nitrate, and silver acetate can be mentioned. Among these, silver(I) nitrate is preferable in terms of high solubility and ease of industrial use.

[0022] The above silver salts may be used alone or in combination of two or more.

[0023] The content of component (A) in the electroless plating catalyst solution is not particularly limited, preferably 0.01 to 10 g / L, more preferably 0.05 to 5 g / L, still more preferably 0.1 to 3 g / L, and particularly preferably 0.3 to 1 g / L. When the lower limit of the content of component (A) is within the above range, a silver catalyst can be more sufficiently imparted to the object to be plated. When the upper limit of the content of component (A) is within the above range, the precipitation of metallic silver in the electroless plating catalyst solution is more suppressed, and the solution stability is further improved.

[0024] (A) The average particle diameter of the silver nanoparticles is preferably 1 to 200 nm, more preferably 1 to 50 nm. When the lower limit of the average particle diameter is within the above range, the silver catalyst can be more sufficiently provided on the object to be plated. When the upper limit of the average particle diameter is within the above range, the precipitation of metallic silver in the electroless plating catalyst solution is more suppressed, and the liquid stability is more improved.

[0025] In this specification, (A) the average particle diameter of the silver nanoparticles is measured by a measurement method using a transmission electron microscope (TEM). Specifically, a field in which the particles are dispersed is randomly selected, the diameters of independent particles are measured, the average value and the standard deviation of the diameters of at least 100 or more particles are calculated, and this is taken as the average particle diameter. Note that FIG. 1 shows a TEM image when measuring the average particle diameter of the silver nanoparticles in the electroless plating catalyst solution of the present invention. The average particle diameter measured from the TEM image of FIG. 1 is 14.1 ± 3.2 nm.

[0026] ((B) Reducing agent) The electroless plating catalyst solution of the present invention contains (B) a reducing agent (hereinafter also referred to as “(B) component”).

[0027] As the (B) component, a reducing agent that exhibits catalytic activity with respect to silver can be preferably used. Examples of such reducing agents include dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, hydrazine, hypophosphite, erythorbic acid, ascorbic acid, hydroxylamine sulfate, hydrogen peroxide, glucose, and the like. Among these, dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, and hydrazine are preferable, and dimethylamine borane is more preferable in that the silver catalyst can be favorably provided on the object to be plated.

[0028] The content of component (B) in the electroless plating catalyst solution is not particularly limited, preferably 0.001 to 10 g / L, more preferably 0.002 to 1 g / L, still more preferably 0.003 to 0.5 g / L, and particularly preferably 0.004 to 0.1 g / L. When the lower limit of the content of component (B) is within the above range, a silver catalyst can be more sufficiently imparted to the object to be plated. When the upper limit of the content of component (B) is within the above range, the precipitation of metallic silver in the electroless plating catalyst solution is more suppressed, and the liquid stability is further improved.

[0029] ((C) acid component) The electroless plating catalyst solution of the present invention contains a (C) acid component (hereinafter, also referred to as "(C) component").

[0030] In the electroless plating catalyst solution of the present invention, the (C) component is at least one acid component selected from the group consisting of oxo acids and organic acids.

[0031] The oxo acid is not particularly limited, and examples thereof include hypophosphorous acid, phosphorous acid, thiosulfuric acid, and the like.

[0032] The organic acid is not particularly limited, and examples thereof include carboxylic acid, ascorbic acid, and the like.

[0033] As the (C) component, carboxylic acid is preferable in that a silver catalyst can be more sufficiently imparted to the object to be plated.

[0034] The carboxylic acid is not particularly limited, and examples thereof include formic acid, oxalic acid, glycolic acid, tartaric acid, citric acid, maleic acid, acetic acid, propionic acid, malonic acid, succinic acid, lactic acid, malic acid, gluconic acid, glycine, alanine, aspartic acid, glutamic acid, iminodiacetic acid, nitrilotriacetic acid, fumaric acid, and the like. Among these, formic acid, acetic acid, tartaric acid, and citric acid are preferable in that a silver catalyst can be favorably imparted to the object to be plated and the liquid stability of the electroless plating catalyst solution is further improved.

[0035] The content of component (C) in the electroless plating catalyst solution is not particularly limited, preferably 0.001 to 20 g / L, more preferably 0.01 to 10 g / L, and still more preferably 0.02 to 8 g / L. When the lower limit of the content of component (C) is within the above range, a silver catalyst can be more sufficiently imparted to the object to be plated. When the upper limit of the content of component (C) is within the above range, the precipitation of metallic silver in the electroless plating catalyst solution is more suppressed, and the liquid stability is more improved.

[0036] ((D) Silver nanoparticle dispersant) In addition to the above components (A) to (C), the electroless plating catalyst solution of the present invention may further contain (D) a silver nanoparticle dispersant (hereinafter, also referred to as "component (D)"). When the electroless plating catalyst solution of the present invention contains component (D), the precipitation of metallic silver in the electroless plating catalyst solution is more suppressed, and the liquid stability is more improved.

[0037] Component (D) is not particularly limited as long as silver nanoparticles (A) can be dispersed in the electroless plating catalyst solution of the present invention. As such component (D), a silver nanoparticle dispersant other than the above component (B) can be used, such as a phosphoric acid compound such as polyoxyethylene alkyl ether phosphoric acid; an ammonium salt such as polydiallyldimethylammonium chloride; and cellulose such as carboxymethyl cellulose. Among these, a phosphoric acid compound is preferable, and polyoxyethylene alkyl ether phosphoric acid is more preferable in terms of further improving the liquid stability of the electroless plating catalyst solution.

[0038] The content of component (D) in the electroless plating catalyst solution is not particularly limited, preferably 0.001 to 1 g / L, more preferably 0.01 to 0.5 g / L, and still more preferably 0.02 to 0.1 g / L. When the lower limit of the content of component (D) is within the above range, the liquid stability of the electroless plating catalyst solution is more improved.

[0039] ((E) Nonionic surfactant) The electroless plating catalyst solution of the present invention may contain (E) a nonionic surfactant (hereinafter, also referred to as “(E) component”). When the electroless plating catalyst solution of the present invention contains the (E) component, the precipitation of metallic silver in the electroless plating catalyst solution is further suppressed, and the liquid stability is further improved.

[0040] (E) The component is not particularly limited as long as (E) silver nanoparticles can be dispersed in the electroless plating catalyst solution of the present invention. Examples of such (E) components include polyoxyalkylene alkyl ether, polyoxyalkylene phenyl ether, polyoxyalkylene naphthyl ether, polyoxyalkylene alkyl ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene sorbit fatty acid ester, polyethylene glycol fatty acid ester, polyoxyalkylene glycerin fatty acid ester, polyoxyalkylene alkylamine, sorbitan fatty acid ester, glycerin fatty acid ester, and the like. Among these, polyoxyalkylene alkyl ether is preferable, and polyoxyalkylene alkyl ether is more preferable in terms of further suppressing the precipitation of metallic silver in the electroless plating catalyst solution and further improving the liquid stability.

[0041] The content of the (E) component in the electroless plating catalyst solution is not particularly limited, preferably 0.001 to 1 g / L, more preferably 0.01 to 0.5 g / L, and still more preferably 0.02 to 0.1 g / L. When the lower limit of the content of the (E) component is within the above range, the liquid stability of the electroless plating catalyst solution is further improved.

[0042] (E) The HLB of the nonionic surfactant is preferably 8.0 or more, more preferably 10 or more, still more preferably 13 or more, and particularly preferably 14 or more. Also, the upper limit of the above HLB is not particularly limited, preferably 18 or less, and more preferably 17 or less. When the HLB is within the above range, the liquid stability of the electroless plating catalyst solution is further improved.

[0043] (Solvent) The electroless plating catalyst solution of the present invention preferably contains the above components (A) to (C), and components (D) and (E) added as necessary in a solvent. The solvent is not particularly limited, and examples thereof include water, alcohol, and a mixed solvent of water and alcohol.

[0044] In terms of excellent safety, water is preferred as the solvent. That is, the electroless plating catalyst solution of the present invention is preferably an aqueous solution.

[0045] The alcohol is not particularly limited, and conventionally known alcohols such as ethanol can be used.

[0046] When using a mixed solvent of water and alcohol, the concentration of alcohol is preferably low. Specifically, the alcohol concentration in the mixed solvent is preferably about 1 to 30% by mass.

[0047] The pH of the electroless plating catalyst solution of the present invention is preferably 1 or more and 11 or less, more preferably 2 or more and 10 or less, and even more preferably 4 or more and 9 or less. When the pH is within the above range, a silver catalyst can be more sufficiently applied to the object to be treated.

[0048] (Other components) The electroless plating catalyst solution of the present invention may contain other components in addition to the above components. Examples of such other components include anti-mist agents and defoaming agents.

[0049] The content of other components is not particularly limited. In total, the other components are preferably 10 g / L or less, more preferably 5 g / L or less, even more preferably 3 g / L or less, and particularly preferably 1 g / L or less. Also, the lower limit of other components is preferably lower, and may be 0 g / L, 0.1 g / L, etc.

[0050] 2. Pretreatment method for electroless plating of resin materials The pretreatment method for electroless plating of the resin material of the present invention has step 1 of bringing the surface to be treated of the resin material into contact with the catalyst solution for electroless plating. The catalyst solution for electroless plating contains (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and is a pretreatment method for electroless plating having an oxidation-reduction potential of 0 mV or more and 400 mV or less at 25°C. This will be described below.

[0051] (Step 1) Step 1 is a step of bringing the surface to be treated of the resin material into contact with the catalyst solution for electroless plating. As the catalyst solution for electroless plating, the one described as the catalyst solution for electroless plating of the present invention as described above can be used.

[0052] The method of bringing the surface to be treated of the resin material into contact with the catalyst solution for electroless plating is not particularly limited, and it may be brought into contact by a conventionally known method. Examples of such methods include a method of immersing the resin material in the catalyst solution for electroless plating, a method of spraying the catalyst solution for electroless plating onto the surface to be treated of the resin material, and the like. Among these, the method of immersing the resin material in the catalyst solution for electroless plating is preferable in terms of further excellent contact efficiency.

[0053] The temperature of the catalyst solution for electroless plating in step 1 is not particularly limited, preferably 10 to 70°C, more preferably 20 to 50°C, and still more preferably 30 to 40°C. By setting the lower limit of the temperature of the catalyst solution for electroless plating within the above range, the application of the catalyst on the surface of the resin material becomes more sufficient. Also, by setting the upper limit of the temperature of the catalyst solution for electroless plating within the above range, the liquid stability of the catalyst solution for electroless plating is further improved.

[0054] In step 1, the contact time between the pretreatment composition and the surface to be treated of the resin material is preferably 1 to 30 minutes, more preferably 2 to 20 minutes, and still more preferably 3 to 10 minutes. By setting the lower limit of the contact time within the above range, the application of the catalyst on the surface of the resin material becomes more sufficient. Also, by setting the upper limit of the contact time within the above range, the liquid stability of the catalyst solution for electroless plating is further improved.

[0055] The resin forming the resin material to be processed is not particularly limited, and various resin materials conventionally used for the pretreatment of electroless plating of resin materials can be used. Examples of the resin forming the resin material include styrene resins such as acrylonitrile-butadiene-styrene copolymer resin (ABS resin), resin (AAS resin) in which the butadiene rubber component of ABS resin is replaced by an acrylic rubber component, and resin (AES resin) in which the butadiene rubber component of ABS resin is replaced by an ethylene-propylene rubber component or the like. Also, alloy resins of the above styrene resins and polycarbonate (PC) resins (for example, alloy resins with a PC resin mixing ratio of about 30 to 70% by mass) can be preferably used. Furthermore, polyphenylene ether resins, polyphenylene oxide resins, polybutylene terephthalate (PBT) resins, polyphenylene sulfide (PPS) resins, polyamide resins, etc., which are excellent in heat resistance and physical properties, can also be used.

[0056] The shape, size, etc. of the resin material are not particularly limited, and according to the pretreatment method of the present invention, a plating film can be sufficiently formed even on a large resin material with a large surface area. Examples of such large resin materials include automobile-related parts such as radiator grills, wheel caps, medium and small emblems, door handles; exterior parts in the electric and electronic fields; faucet fittings used in water circuits; and gaming machine-related parts such as pachinko parts.

[0057] Through the above-described step 1, the surface to be treated of the resin material is brought into contact with the electroless plating catalyst solution.

[0058] 3. Electroless plating method for resin materials The electroless plating method of the resin material of the present invention is (1) Step 1 of bringing the surface of the resin material to be treated into contact with the electroless plating catalyst solution, and (2) Step 2 of bringing the surface of the resin material to be treated into contact with the electroless plating solution. The electroless plating catalyst solution contains (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and is an electroless plating method having a redox potential at 25°C of 0 mV or more and 400 mV or less.

[0059] (Step 1) Step 1 in the electroless plating method of the resin material of the present invention is the same as the step described as Step 1 in the pretreatment method of electroless plating of the resin material described above.

[0060] (Step 2) Step 2 is a step of bringing the surface of the resin material to be treated into contact with the electroless plating solution.

[0061] The method of bringing the surface of the resin material to be treated into contact with the electroless plating solution is not particularly limited, and it may be brought into contact by a conventionally known method. As the method, a method of immersing the surface of the resin material to be treated in the electroless plating solution is preferable in terms of further excellent contact efficiency.

[0062] The electroless plating solution is not particularly limited, and a conventionally known autocatalytic electroless plating solution can be used. Examples of the electroless plating solution include electroless nickel plating solution, electroless copper plating solution, electroless cobalt plating solution, electroless nickel-cobalt alloy plating solution, electroless gold plating solution, and the like.

[0063] The electroless plating solution preferably contains, as a reducing agent, a reducing agent that exhibits catalytic activity with respect to silver. Examples of the reducing agent include dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, hydrazine, and the like.

[0064] The conditions for bringing the surface of the resin material into contact with the electroless plating solution are not particularly limited. For example, when the resin material is immersed in the electroless plating solution, the liquid temperature of the electroless plating solution may be about 20 to 70 °C, and the immersion time may be about 3 to 30 minutes.

[0065] The content of the reducing agent in the electroless plating solution is not particularly limited, and is preferably about 0.01 to 100 g / L, and more preferably about 0.1 to 10 g / L. By setting the lower limit of the content of the reducing agent within the above range, the deposition property of the plating is further improved, and by setting the upper limit of the content of the reducing agent within the above range, the liquid stability of the electroless plating bath is further improved.

[0066] In the electroless plating method of the present invention, if necessary, step 2 may be repeated two or more times. By repeating step 2 two or more times, two or more layers of electroless plating films are formed.

[0067] In order to improve the deposition property of the electroless plating, the electroless plating method of the present invention may be subjected to an activation treatment with an activation treatment solution containing a reducing agent and / or an organic acid before step 2.

[0068] The reducing agent used for the activation treatment is not particularly limited, and examples thereof include dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, hydrazine, hypophosphite, erythorbic acid, ascorbic acid, hydroxylamine sulfate, hydrogen peroxide, glucose, etc. Among these, dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, and hydrazine are preferable in that the plating deposition property is further improved.

[0069] The above reducing agent may be used alone or in combination of two or more.

[0070] The concentration of the reducing agent in the activation treatment solution is not particularly limited, and is preferably 0.05 to 100 g / L, more preferably about 0.1 to 50 g / L, and still more preferably 0.5 to 25 g / L.

[0071] The organic acid used for the activation treatment is not particularly limited, and examples include formic acid, oxalic acid, glycolic acid, tartaric acid, citric acid, maleic acid, acetic acid, propionic acid, malonic acid, succinic acid, lactic acid, malic acid, gluconic acid, glycine, alanine, aspartic acid, glutamic acid, iminodiacetic acid, nitrilotriacetic acid, fumaric acid, etc. Among these, formic acid, oxalic acid, glycolic acid, tartaric acid, citric acid, and maleic acid are preferred in that the plating deposition property is even better.

[0072] The above organic acid may be used alone or in combination of two or more.

[0073] The concentration of the organic acid in the activation treatment solution is not particularly limited, preferably 0.1 to 500 g / L, more preferably about 1 to 50 g / L, and still more preferably 2 to 25 g / L.

[0074] The activation treatment method is not particularly limited. For example, the resin material pretreated in the above step 1 may be immersed in the activation treatment solution at a liquid temperature of about 15 to 50 °C for about several seconds to 10 minutes.

[0075] In the electroless plating method of the resin material of the present invention, after step 2, an electroplating step may further be included.

[0076] In the electroplating step, after the above step 2, if necessary, activation treatment may be performed with an aqueous solution such as an acid or an alkali, and then immersed in an electroplating solution to perform electroplating.

[0077] The electroplating solution is not particularly limited and may be appropriately selected from conventionally known electroplating solutions according to the purpose.

[0078] The electroplating method is not particularly limited. For example, in the activation treatment solution at a liquid temperature of about 15 to 50 °C, the resin material on which the electroless plating film is formed in the above step 2 is immersed under conditions of a current density of 0.1 to 10 A / dm 2 for about several seconds to 10 minutes.

Examples

[0079] Examples and comparative examples are shown below to specifically describe the present invention. However, the present invention is not limited to the examples.

[0080] (Preparation of electroless plating film) As the resin material to be plated, a flat plate (10 cm × 5 cm × 0.3 cm, surface area of about 1 dm 2 ) of ABS resin (manufactured by UMG ABS Co., Ltd., trade name: UMG ABS3001M) was prepared, and an electroless plating film was formed by the method shown in Table 1 below.

[0081]

Table 1

[0082] Note that the stock solution of the electroless plating catalyst solution used in the catalysis in Table 1 was prepared according to the procedure in Table 2 below.

[0083]

Table 2

[0084] The formulations of the stock solutions of the electroless plating catalyst solutions prepared according to the procedure in Table 2 are shown in Tables 3 and 4 below. Also, in Tables 3 and 4 below, the numerical values in parentheses are the concentrations (g / L) of each component in the electroless plating catalyst solution when the stock solution of the electroless plating catalyst solution was diluted to 50 ml / L with pure water to prepare the electroless plating catalyst solution. Also, the surfactant was not included in the stock solution of the electroless plating catalyst solution, and the electroless plating catalyst solution was prepared by adding it when the stock solution was diluted with pure water. The concentration of the surfactant in the electroless plating catalyst solution was 1 g / L.

[0085]

Table 3

[0086]

Table 4

[0087] In Table 3, the following surfactants were used. · Polyoxyalkylene alkyl ether A: Colorless liquid, HLB value 14.1, cloud point 80°C · Polyoxyalkylene alkyl ether B: White flaky, HLB value 17.8, no cloud point · Polyoxyalkylene alkyl ether C: White paste, HLB value 14.4, cloud point 97°C · Polyoxyalkylene alkyl ether D: White solid, HLB value 17.7, no cloud point · Polyoxyethylene polyoxypropylene glycol A: Colorless paste, HLB value 8.1, cloud point 56°C · Polyoxyethylene polyoxypropylene glycol B: Colorless paste, HLB value 10.1, cloud point 69°C · Polyoxyethylene polyoxypropylene glycol C: White flaky, HLB value 15.7, no cloud point

[0088] The stock solutions of the examples and comparative examples were diluted with water to a concentration of 50 ml / L to prepare electroless plating catalyst solutions for the examples and comparative examples. In the examples containing a surfactant, the solution was prepared to a volume of 1 L including the surfactant.

[0089] Using the electroless plating catalyst solution prepared as described above, electroless plating was performed on the object to be plated by the method shown in Table 1 to prepare samples. Using the prepared samples, the following evaluations were conducted.

[0090] Redox potential (ORP) measurement Using an ORP meter manufactured by HORIBA, the oxidation-reduction potential was measured under the condition of a measurement temperature of 25°C.

[0091] Deposition rate The deposition rate of electroless nickel plating of the electroless plating catalyst solution was evaluated visually. The measurement was performed on the electroless plating catalyst solution immediately after preparation and the electroless plating catalyst solution 30 days after preparation.

[0092] The results are shown in Tables 5 and 6. In Tables 5 and 6, the concentration of each component is the concentration (g / L) of each component in the electroless plating catalyst solution after diluting the stock solution of the electroless plating catalyst solution with pure water.

[0093] [Table 5]

[0094] [Table 6]

Claims

1. containing (A) silver nanoparticles, (B) a reducing agent, and at least one acid component selected from the group consisting of (C) oxo acids and organic acids, having a redox potential at 25 °C of 0 mV or more and 400 mV or less, and being a catalyst solution for electroless plating, characterized by this.

2. The catalyst solution for electroless plating according to Claim 1, wherein the average particle diameter of the silver nanoparticles is 1 to 200 nm.

3. The catalyst solution for electroless plating according to Claim 1, wherein the content of the silver nanoparticles is 0.1 to 80% by mass with the catalyst solution for electroless plating being 100% by mass.

4. The catalyst solution for electroless plating according to Claim 1, wherein the oxo acid is at least one selected from the group consisting of hypophosphorous acid, phosphorous acid, and thiosulfuric acid, and the organic acid is at least one selected from the group consisting of carboxylic acid and ascorbic acid.

5. The catalyst solution for electroless plating according to Claim 1, wherein the reducing agent is at least one selected from the group consisting of dimethylamine borane and sodium borohydride.

6. Further containing (D) a silver nanoparticle dispersant, and the (D) silver nanoparticle dispersant being polyoxyethylene alkyl ether phosphate, the catalyst solution for electroless plating according to Claim 1.

7. Further containing (E) a nonionic surfactant, and the nonionic surfactant being polyoxyalkylene alkyl ether, the catalyst solution for electroless plating according to Claim 1.

8. A pretreatment method for electroless plating of a resin material, having step 1 of bringing the surface to be treated of the resin material into contact with the catalyst solution for electroless plating, The electroless plating catalyst solution contains (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and has a redox potential at 25°C of 0 mV or more and 400 mV or less. The pretreatment method is characterized by this.

9. An electroless plating method for a resin material, (1) Step 1 of bringing the surface to be treated of the resin material into contact with the electroless plating catalyst solution, and (2) It has Step 2 of bringing the surface to be treated of the resin material into contact with an electroless plating solution. The electroless plating catalyst solution contains (A) silver nanoparticles, (B) a reducing agent, and (C) at least one acid component selected from the group consisting of oxo acids and organic acids, and has a redox potential at 25°C of 0 mV or more and 400 mV or less. The electroless plating method is characterized by this.

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