JP2019203168A - Pretreatment composition for electroless plating, pretreatment method for electroless plating, and electroless plating method - Google Patents

Abstract

To provide a pretreatment composition for electroless plating, a pretreatment method for electroless plating, and an electroless plating method that can ensure high plating deposition without using harmful chromate or expensive palladium, and can reduce the number of steps.SOLUTION: A pretreatment composition for electroless plating containing 10 mg/L or more of persulfuric acid ions and 10 mg/L or more of monovalent silver ions is brought into contact with a target surface of a resin material at higher than 60°C, and the target surface of the resin material is further brought into contact with an electroless plating liquid.SELECTED DRAWING: None

Description

  The present invention relates to a pretreatment composition for electroless plating, a pretreatment method for electroless plating, and an electroless plating method.

  In recent years, resin molded bodies have been used as automobile parts for the purpose of reducing the weight of automobiles. For such purposes, for example, ABS resin, PC / ABS resin, PPE resin, polyamide resin, etc. are used as the resin molded body, and plating such as copper and nickel is applied to give a high-class feeling and aesthetic appearance. Has been. Furthermore, as a method of forming a conductive circuit by imparting conductivity to a resin substrate, a method of forming a plating film such as copper on the resin substrate has been performed.

  As a general method for forming a plating film on a resin material such as a resin substrate or resin molded body, the surface of the resin material is roughened by etching with chromic acid, and then neutralized and pre-diped as necessary. Then, a catalyst for electroless plating is applied using a colloidal solution containing a tin compound and a palladium compound, and then an activation treatment (accelerator treatment) is performed to remove tin, and electroless plating and electroplating are performed. Sequential methods are used.

  However, the above-described method has a problem that it is harmful to the environment and the human body because chromic acid is used. Moreover, since expensive palladium is used for providing a catalyst, there exists a problem that cost becomes high. Moreover, after performing an etching process, it is necessary to perform a catalyst provision process separately, and there exists a problem that a process increases.

  As a method of forming a plating film on a resin material, an aqueous solution containing a metal activator molecular species is contacted with a part to be plated and etched, and then contacted with a solution of a reducing agent capable of reducing the metal activator molecular species. A method of metal plating by bringing a part into contact with an electroless plating solution has been proposed (see Patent Document 1).

  However, the method described in Patent Document 1 has a problem that there is room for study on the component of the activator molecular species, and the formation of the plating film is not sufficient.

  Therefore, a composition for pretreatment of electroless plating that can exhibit high plating deposition properties and can reduce the steps without using harmful chromic acid and expensive palladium, and a pretreatment method Development of electroless plating methods is demanded.

  When manufacturing printed circuit boards to be subjected to chemical plating, an adhesive layer containing diene rubber is provided on the surface to be plated, and then the surface of the adhesive contains oxidants containing silver salt and persulfate. There has been proposed a method of forming an underlayer for chemical plating in contact with an etching solution (see Patent Document 2). In the method described in Patent Document 2, the temperature of the etching bath is from room temperature to 60 ° C., that is, not used at a bath temperature exceeding 60 ° C.

  In the pretreatment method of electroless plating for a resin molded body, the resin molded body is etched into an aqueous solution containing a reducing compound and an inorganic acid after etching the resin molded body using an etching solution containing manganate. There has been proposed a pretreatment method including a step of contacting (see Patent Document 3). The etchant may further contain persulfate. In the method using the etching solution, the electroless plating is further performed by performing a step of adjusting the surface by contacting with an aqueous solution containing an amine compound, a step of applying a catalyst for electroless plating, and the like.

  As a method for treating a plastic surface, a method of treating plastic with a solution obtained by electrolyzing sulfuric acid has been proposed (see Patent Document 4). The solution may contain persulfuric acid. In the method using the sulfuric acid solution, electroless nickel plating is further performed through a catalyst application step and an activation step.

Japanese Patent No. 4198799 JP 54-81127 A International Publication Number WO2008 / 143190 (Patent No. 5585980) JP 2017-197831

  The present invention has been made in view of the above problems, and can exhibit high plating deposition properties and can reduce the number of steps without using harmful chromic acid and expensive palladium. An object of the present invention is to provide an electroless plating pretreatment composition, a pretreatment method, and an electroless plating method.

  As a result of intensive studies to achieve the above object, the present inventors have conducted a condition exceeding 60 ° C. for electroless plating containing 10 mg / L or more of persulfate ions and 10 mg / L or more of monovalent silver ions. According to the pretreatment composition, the pretreatment method, and the electroless plating method used in the above, the inventors have found that the above object can be achieved, and have completed the present invention.

  That is, the present invention relates to the following electroless plating pretreatment composition, pretreatment method, and electroless plating method.

Item 1.
A composition for pretreatment used under conditions exceeding 60 ° C. for electroless plating, comprising persulfate ions of 10 mg / L or more and monovalent silver ions of 10 mg / L or more.

Item 2.
Item 2. The pretreatment composition according to Item 1, wherein the pH is 1 or less.

Item 3.
Item 3. The composition for pretreatment according to Item 1 or 2, for simultaneously performing etching of the surface to be treated and applying a catalyst when the surface to be treated of the resin substrate is brought into contact with the composition for pretreatment.

Item 4.
A pretreatment method for electroless plating of a resin material,
The pretreatment composition has a step 1 of bringing the surface to be treated of the resin material into contact with the composition at a temperature exceeding 60 ° C.
The pretreatment composition contains 10 mg / L or more of persulfate ions and 10 mg / L or more of monovalent silver ions.
A pretreatment method of electroless plating characterized by the above.

Item 5.
An electroless plating method for a resin material,
(1) Step 1 for bringing the surface to be treated of the resin material into contact with the pretreatment composition at a temperature exceeding 60 ° C., and (2) bringing the surface to be treated for the resin material into contact with an electroless plating solution. Step 2
The pretreatment composition contains 10 mg / L or more of persulfate ions and 10 mg / L or more of monovalent silver ions.
An electroless plating method characterized by the above.

Item 6.
Item 6. The electroless plating method according to Item 5, wherein the electroless plating solution contains a reducing agent having catalytic activity for silver.

  According to the pretreatment composition for electroless plating of the present invention, high plating deposition can be achieved in electroless plating in the subsequent step without using harmful chromic acid and expensive palladium. Further, according to the pretreatment composition for electroless plating of the present invention, it is not necessary to separately perform the etching step and the catalyst application step, and the number of steps when performing electroless plating can be reduced.

  Further, according to the pretreatment method of electroless plating of the present invention, the surface to be treated is etched by bringing the surface to be treated of the resin material into contact with the composition for pretreatment, and the surface to be treated is treated. Since the silver catalyst can be applied, the surface to be treated of the resin material can be easily treated, and the pretreatment process can be reduced.

  Further, according to the electroless plating method of the present invention, in the pretreatment step, the surface to be treated of the resin material is brought into contact with the composition for pretreatment, so that the surface to be treated is etched, and the surface to be treated is treated. Since the silver catalyst can be applied to the surface, and the catalyst application step and the accelerator treatment step are not required, the surface to be treated of the resin material can be easily treated, and the step for performing electroless plating Can be reduced.

  In addition, according to the pretreatment composition of the electroless plating of the present invention, since chromic acid etching which is a conventional technique and heavy metal ions having high oxidizing power are not used as compared with an etching solution using a manganese salt, Excellent drainage treatment.

  Hereinafter, the present invention will be described in detail.

1. Composition for pretreatment of electroless plating The composition for pretreatment of electroless plating of the present invention (hereinafter also simply referred to as “pretreatment composition”) is a composition for pretreatment used under conditions exceeding 60 ° C. A persulfate ion of 10 mg / L or more and monovalent silver ion of 10 mg / L or more. Since the pretreatment composition of the present invention contains a specific amount of persulfate ions and a specific amount of monovalent silver ions, a decrease in etching power on the surface to be treated of the resin material is suppressed, and the application of the catalyst Is enough.

For example, in a pretreatment composition containing chromic acid and silver ions, a precipitate of silver chromate (Ag ₂ CrO ₄ ), which is an insoluble precipitate in the composition, is generated and silver ions are discharged out of the system. The catalyst is not sufficiently applied.

  On the other hand, since the pretreatment composition of the present invention contains persulfate ions and monovalent silver ions, the treated surface of the resin material is brought into contact with the treated surface under conditions exceeding 60 ° C. By bringing the surface into contact with the electroless plating solution, a plating film having good adhesion can be formed on the surface to be treated.

  In addition, since the pretreatment composition of the present invention contains persulfate ions and monovalent silver ions, etching of the surface to be treated and catalyst application are simultaneously performed by bringing the surface to be treated of the resin substrate into contact. Therefore, the catalyst application step can be omitted. That is, the pretreatment composition of the present invention simultaneously etches the surface to be treated and applies a catalyst when the surface to be treated of the resin substrate is brought into contact with the pretreatment composition at a temperature exceeding 60 ° C. Therefore, it is an optimal pretreatment composition.

  Furthermore, the pretreatment composition of the present invention does not require the use of a palladium-tin colloid solution as in the conventional catalyst application step, and the activation treatment (accelerator treatment) step for removing tin can be omitted. It becomes.

  That is, according to the pretreatment composition of the present invention, it is possible to exhibit high plating deposition properties in electroless plating in the subsequent step without using harmful chromic acid and expensive palladium. Further, according to the pretreatment composition for electroless plating of the present invention, it is not necessary to perform the etching step and the catalyst application step separately, and it is not necessary to perform the accelerator treatment step. This process is greatly shortened.

(Persulfate ion)
The compound for imparting persulfate ions to the pretreatment composition is not particularly limited, and it is preferable to use persulfuric acid or a salt thereof.

  The persulfate ion may be peroxomonosulfate ion, peroxodisulfate ion, or a mixture of peroxomonosulfate ion and peroxodisulfate ion.

  As a compound for imparting peroxomonosulfate ion or peroxodisulfate ion, it is preferable to use potassium salt, ammonium salt, cesium salt, thallium salt or the like. As the compound for imparting persulfate ions, for example, sodium persulfate, potassium persulfate, ammonium persulfate and the like are preferably used.

  Further, persulfuric acid generated by electrolysis of sulfuric acid may be used. When sulfuric acid is electrolyzed, sulfuric acid is electrolyzed to produce persulfuric acid such as peroxodisulfuric acid.

  A persulfate may be used individually by 1 type, and may use 2 or more types together.

  In the pretreatment composition of the present invention, the content of persulfate ions is 10 mg / L or more. If the content of persulfate ions is less than 10 mg / L, the resin material cannot be etched sufficiently, and the adhesion of a film formed by electroless plating is lowered. The content of persulfate ions is preferably 10 mg / L to 300 g / L, more preferably 100 mg / L to 200 g / L, still more preferably 0.5 g / L to 100 g / L, and 1 g / L to 50 g / L. Particularly preferred. By setting the lower limit of the content of persulfate ions in the above range, the etching power of the pretreatment composition is further improved.

(Silver ion)
The silver ion contained in the pretreatment composition of the present invention is a monovalent silver ion. As a silver salt for imparting monovalent silver ions, it is possible to impart stable monovalent silver ions in a bath when dissolved in the pretreatment composition, and a counter ion that forms a silver salt. Is not particularly limited as long as it does not adversely affect persulfate ions. Specific examples include silver sulfate (I), silver nitrate (I), and silver oxide (I). Among these, silver nitrate (I) is preferable because it is highly soluble and easy to use industrially.

  A silver salt may be used individually by 1 type, and may use 2 or more types together.

  In the pretreatment composition of the present invention, the content of monovalent silver ions is 10 mg / L or more. When the content of monovalent silver ions is less than 10 mg / L, electroless plating cannot be sufficiently deposited. The content of monovalent silver ions is preferably 10 mg / L to 20 g / L, more preferably 50 mg / L to 15 g / L, and still more preferably 100 mg / L to 10 g / L. By setting the lower limit of the content of monovalent silver ions in the above range, a sufficient amount of silver catalyst is adsorbed on the surface of the resin material, and the electroless plating film is more sufficiently precipitated. Moreover, even if the upper limit of the content of monovalent silver ions is not less than the above upper limit, there is no adverse effect, but by using the above upper limit, the amount of silver salt used can be suppressed and the cost can be reduced. be able to.

  As the silver ion, monovalent silver obtained by adding metallic silver to an acidic persulfuric acid bath and dissolving it may be used. The acid for forming the acidic persulfuric acid bath is not particularly limited, and inorganic acids and organic sulfonic acids can be used.

  Examples of the inorganic acid include sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, hydrofluoric acid, boric acid and the like. Among these, sulfuric acid is preferable because it is more excellent in wastewater treatment.

  Examples of the organic sulfonic acid include aliphatic sulfonic acids having 1 to 5 carbon atoms such as methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, and pentanesulfonic acid; aromatic sulfones such as toluenesulfonic acid, pyridinesulfonic acid, and phenolsulfonic acid. An acid etc. are mentioned.

  The said acid may be used individually by 1 type, and may use 2 or more types together.

  The acid concentration in the pretreatment composition of the present invention is not particularly limited. For example, the total acid concentration is preferably 100 to 1800 g / L, and more preferably 800 to 1700 g / L.

(solvent)
In the pretreatment composition of the present invention, the persulfate ion, the silver ion, and other components added as necessary are preferably contained in a solvent. It does not specifically limit as said solvent, Water, alcohol, the mixed solvent of water and alcohol, etc. are mentioned.

  The solvent is preferably water in terms of safety, that is, the pretreatment composition of the present invention is preferably an aqueous solution.

  It does not specifically limit as alcohol, Conventionally well-known alcohol, such as ethanol, can be used.

  When a mixed solvent of water and alcohol is used, the alcohol concentration is preferably low, and specifically, the alcohol concentration is preferably about 1 to 30% by mass.

  The pretreatment composition of the present invention is preferably acidic. Since the pretreatment composition is acidic, the etching treatment of the resin material becomes more sufficient. The pH of the pretreatment composition of the present invention is preferably 1 or less, and more preferably 0.5 or less.

2. Pretreatment method for electroless plating of resin material The pretreatment method for electroless plating of a resin material according to the present invention includes a step 1 of bringing a surface to be treated of the resin material into contact with a pretreatment composition, The composition for treatment is a pretreatment method for electroless plating containing persulfate ions of 10 mg / L or more and monovalent silver ions of 10 mg / L or more.

(Process 1)
Step 1 is a step of bringing the surface to be treated of the resin material into contact with the pretreatment composition under conditions exceeding 60 ° C.

  As the pretreatment composition, those described as the pretreatment composition for electroless plating can be used.

  The method for bringing the treated surface of the resin material into contact with the pretreatment composition is not particularly limited, and may be brought into contact with a conventionally known method. Examples of the method include a method of immersing the resin material in the pretreatment composition, a method of spraying the pretreatment composition on the surface to be treated of the resin material, and the like. Among these, the method of immersing the resin material in the pretreatment composition is preferable in that the contact efficiency is further improved.

  The temperature of the pretreatment composition in step 1 is appropriately set under conditions exceeding 60 ° C. The temperature of the pretreatment composition in step 1 is preferably in the range of more than 60 ° C and up to 100 ° C, more preferably in the range of more than 60 ° C and up to 90 ° C, more than 60 ° C and more than 80 ° C. A temperature range up to 0C is more preferred. By setting the lower limit of the temperature of the pretreatment composition within the above range, etching of the surface of the resin material and application of a catalyst become more sufficient. Moreover, the film | membrane external appearance which was further excellent in the decorating property can be obtained by making the upper limit of the temperature of the composition for pretreatment into the said range.

  The temperature exceeding 60 ° C. as the temperature of the pretreatment composition is preferably, for example, a temperature range of 62 ° C. or higher, and more preferably a temperature range of 65 ° C. or higher.

  The contact time between the pretreatment composition and the treated surface of the resin material in Step 1 is preferably 3 to 60 minutes, more preferably 5 to 50 minutes, and still more preferably 10 to 40 minutes. By setting the lower limit of the contact time of the pretreatment composition within the above range, when the surface to be treated of the resin material is brought into contact with the pretreatment composition at a temperature exceeding 60 ° C., etching of the resin material surface and The catalyst application is more sufficient. Moreover, the film | membrane external appearance which was further excellent in the decorating property can be obtained by making the upper limit of contact time into the said range.

In the case of using a conventional chromic acid-sulfuric acid mixed solution, silver chromate (Ag ₂ CrO ₄ ) precipitates immediately when monovalent silver ions are added to the bath, so silver is a pretreatment composition. It cannot exist stably as ions in things. Therefore, when the conventional chromic acid-sulfuric acid mixture is used, it is difficult to use a pretreatment composition containing silver ions as in the present invention.

  The resin that forms the resin material to be processed is not particularly limited, and various resin materials that have been conventionally etched with a mixed acid of chromic acid-sulfuric acid can be used. A good electroless plating film can be formed. Examples of the resin forming the resin material include acrylonitrile-butadiene-styrene copolymer resin (ABS resin), a resin in which the butadiene rubber component of the ABS resin is replaced with an acrylic rubber component (AAS resin), and the butadiene rubber component of the ABS resin. Is a styrene resin such as a resin (AES resin) replaced with an ethylene-propylene rubber component. In addition, an alloyed resin of the above styrene-based resin and a polycarbonate (PC) resin (for example, an alloyed resin having a PC resin mixing ratio of about 30 to 70% by mass) can be suitably used. Furthermore, polyphenylene ether resin, polyphenylene oxide resin, polybutylene terephthalate (PBT) resin, polyphenylene sulfide (PPS) resin, polyamide resin, etc. excellent in heat resistance and physical properties can also be used.

  The shape, size, etc. of the resin material are not particularly limited, and according to the pretreatment method of the present invention, a good plating film excellent in decorative properties and physical properties can be formed even on a large resin material having a large surface area. can do. Such large resin materials include radiator grills, wheel caps, medium and small emblems, door handles, and other automotive parts; exterior parts in the electrical and electronic fields; faucet fittings used in water circulation etc. ; Pachinko parts and other gaming machine related products.

  By the process 1 demonstrated above, the to-be-processed surface of a resin material contacts the composition for pre-processing, and the said to-be-processed surface is processed.

  In the pretreatment method of the present invention, degreasing treatment may be performed before step 1 in order to remove dirt on the surface to be treated of the resin material. It does not specifically limit as a degreasing process, What is necessary is just to perform a degreasing process by a conventionally well-known method.

  In the pretreatment method of the present invention, after step 1, in order to remove persulfuric acid adhering to the surface of the resin material, the posttreatment may be performed using a posttreatment liquid containing an inorganic acid.

  The inorganic acid is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, and boric acid. Among these, hydrochloric acid is preferable in terms of excellent persulfuric acid removability.

  The said inorganic acid may be used individually by 1 type, and may use 2 or more types together.

  Content of the inorganic acid in a post-processing liquid is not specifically limited, What is necessary is just to be about 1-1000 g / L.

  It does not specifically limit as a post-processing method, For example, what is necessary is just to immerse the resin material pre-processed by the said pre-processing method for about 1 to 10 minutes in the post-processing liquid about 15-50 degreeC of liquid temperature. By the said post-process, the depositability and external appearance of the plating film formed can be improved further.

  By the pretreatment method of the electroless plating of the resin material described above, the surface to be treated of the resin material can be etched, and a silver catalyst can be applied to the surface to be treated, which is high in electroless plating in the subsequent process. The precipitation of plating can be shown.

3. Electroless Plating Method of Resin Material The electroless plating method of the resin material of the present invention is as follows: (1) Step 1 of bringing the surface to be treated of the resin material into contact with the pretreatment composition under conditions exceeding 60 ° C .; (2) It has the process 2 which makes the to-be-processed surface of the said resin material contact an electroless-plating liquid, The said composition for pre-processing is 10 mg / L or more of persulfate ion and 10 mg / L or more of monovalent | monohydric. This is an electroless plating method containing silver ions.

(Process 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 above pretreatment method of electroless plating of the resin material.

(Process 2)
Step 2 is a step of bringing the treated surface of the resin material into contact with the electroless plating solution.

  The method for bringing the treated surface of the resin material into contact with the electroless plating solution is not particularly limited, and may be brought into contact with a conventionally known method. As the method, a method of immersing the surface to be treated of the resin material in an electroless plating solution is preferable in that the contact efficiency is further improved.

  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 an electroless nickel plating solution, an electroless copper plating solution, an electroless cobalt plating solution, an electroless nickel-cobalt alloy plating solution, and an electroless gold plating solution.

  The electroless plating solution preferably contains a reducing agent exhibiting catalytic activity for silver as the reducing agent. Examples of the reducing agent include dimethylamine borane, formalin, glyoxylic acid, tetrahydroboric acid, hydrazine and the like.

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

  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, more preferably about 0.1 to 10 g / L. By making the lower limit of the reducing agent content within the above range, the deposition properties of the plating are further improved, and by making the upper limit of the reducing agent content within the above range, the stability of the electroless plating bath is further improved. improves.

  In the electroless plating method of the present invention, step 2 may be repeated twice or more as necessary. By repeating step 2 twice or more, two or more electroless plating films are formed.

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

  The reducing agent used for the activation treatment is not particularly limited, and 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 depositability is even better.

  The said reducing agent may be used individually by 1 type, and may use 2 or more types together.

  It does not specifically limit as a density | concentration of the reducing agent in an activation process liquid, 0.1-500 g / L is preferable, About 1-50 g / L is more preferable, 2-25 g / L is still more preferable.

  The organic acid used for the activation treatment is not particularly limited. 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, oxalic acid, glycolic acid, tartaric acid, citric acid, and maleic acid are preferred in that the plating depositability is even better.

  The said organic acid may be used individually by 1 type, and may use 2 or more types together.

  It does not specifically limit as a density | concentration of the organic acid in an activation process liquid, 0.1-500 g / L is preferable, About 1-50 g / L is more preferable, 2-25 g / L is still more preferable.

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

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

  In the electroplating step, after the above step 2, if necessary, an activation treatment may be performed with an aqueous solution of acid, alkali, etc., and the electroplating may be performed by dipping in an electroplating solution.

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

The electroplating method is not particularly limited. For example, a resin material in which an electroless plating film is formed in the above-described step 2 in an activation treatment liquid having a liquid temperature of about 15 to 50 ° C. has a current density of 0.1 to 10 A / it may be immersed a few seconds to 10 minutes in dm ² about the conditions.

  The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to the examples.

(Preparation of electroless plating film)
Prepare a plate (10cm x 5cm x 0.3cm, surface area approx. 1dm ² ) of ABS resin (trade name: UMG ABS3001M, made by UMG ABS Co., Ltd.) as the resin material to be plated. A plating film was formed.

  First, the resin material was immersed in an alkaline degreasing solution (Okuno Pharmaceutical Co., Ltd., Ascreen A-220 bath) at 40 ° C. for 5 minutes and washed with water.

  Next, additives were added to water as a solvent in the formulations shown in Tables 1 and 2 to prepare pretreatment compositions for Examples and Comparative Examples. The resin material after washing with water was immersed in the prepared pretreatment composition under conditions of an immersion temperature of 68 ° C. and an immersion time of 30 minutes.

  Finally, an electroless plating film was formed by immersing the resin material in water at 40 ° C. for 10 minutes in an electroless plating solution prepared by adding an additive with the composition shown in Tables 1 and 2 to water as a solvent. . Similarly, when the immersion temperature was set to 62 ° C. (Example 2) and 58 ° C. (Comparative Example 1), the pretreatment composition was similarly treated using electroless plating prepared from now. An electrolytic plating film was formed.

  The coverage and adhesion of the plating film formed by the above method were evaluated by the following methods.

(1) Coverage rate The ratio of the area where the electroless plating film on the surface of the resin material was formed was evaluated as the coverage rate. When the entire surface of the resin material was coated, the coverage was 100%.

(2) Peel strength measurement The resin material on which the electroless plating film is formed is immersed in a copper sulfate plating bath, and electroplating is performed for 120 minutes at a current density of 3 A / dm ² and a temperature of 25 ° C. Formed and made a sample. The sample was dried at 80 ° C. for 120 minutes and left to reach room temperature. Next, a 10mm wide cut is made in the plating film, and using a tensile tester (manufactured by Shimadzu Corporation, Autograph AGS-J 1kN), the plating film is pulled in the direction perpendicular to the surface of the resin material to peel The strength was measured. The results are shown in Table 3.

  From the results in Table 3, after dipping in the pretreatment composition of Examples 1 to 5 containing persulfate ions of 10 mg / L or more and monovalent silver ions of 10 mg / L or more, dipping in the electroless plating solution It was found that the plating film formed by doing so has a high coverage and excellent adhesion.

  Moreover, since the plating film formed by being immersed in the electroless plating solution after being immersed in the pretreatment compositions of Examples 1 to 6 has a coverage of 100% and is sufficiently covered, It has been found that there is no need to increase the coverage by applying a catalyst in the catalyst application step. For this reason, by using the composition for pretreatment of electroless plating of the present invention, the adhesion of the catalyst to the surface of the jig used in the formation of the electroless plating film is suppressed, and the surface of the jig It was found that the deposition of the plating film was suppressed. As a result, when the electroless plating film is formed by repeatedly using the jig, the plating film deposited on the surface of the jig peels off in a granular shape and is taken into the electroless plating film on the surface of the resin material in each step. Occurrence of unevenness of the electroless plating film on the surface of the resin material is suppressed.

  Comparison between Examples 1 to 6 and Comparative Example 1 shows that the immersion temperature is set to a temperature exceeding 60 ° C. (Examples 1 to 6), so that the coverage becomes 100% and the peel strength exceeds 10 N / cm. Good results. On the other hand, Comparative Example 1 was when the immersion temperature was 58 ° C., and the coverage was insufficient.

  In general, when a resin material is pretreated by etching treatment with chromic acid, and then a catalyst for electroless plating is applied using a colloidal solution containing a tin compound and a palladium compound, chromic acid becomes a catalyst poison, which is cured. The adhesion of the catalyst to the surface of the tool is suppressed, and the deposition of the plating film on the surface of the jig is suppressed. However, when chromic acid is not used in consideration of the environment, etc., the unevenness of the electroless plating film formed on the surface of the resin material described above is caused due to the plating film being deposited on the jig. There is.

  In contrast, the plating film formed by dipping in the electroless plating solution after dipping in the pretreatment composition of the present invention has a coverage of 100% and is sufficiently covered. There is no need to apply a catalyst by the application step and increase the coverage. For this reason, the adhesion of the catalyst to the surface of the jig used in forming the electroless plating film is suppressed, and the deposition of the plating film on the surface of the jig is suppressed, and the surface of the resin material is formed. The unevenness of the electroless plating film is suppressed.

  It was found that when the pretreatment composition of Comparative Example 2 containing no persulfate ion and Comparative Example 3 having a persulfate ion concentration of less than 10 mg / L was used, the adhesion of the plating film was low.

  Moreover, when the composition for pre-processing of Comparative Examples 4 and 5 in which the monovalent silver ion concentration was less than 10 mg / L was used, it was found that the formed plating film was inferior in coverage.

Claims (6)

  A composition for pretreatment used under conditions exceeding 60 ° C. for electroless plating, comprising persulfate ions of 10 mg / L or more and monovalent silver ions of 10 mg / L or more.   The composition for pretreatment according to claim 1, wherein the pH is 1 or less.   The pretreatment composition according to claim 1 or 2, for simultaneously performing etching of the surface to be treated and applying a catalyst when the surface to be treated of the resin substrate is brought into contact with the composition for pretreatment. A pretreatment method for electroless plating of a resin material,
The pretreatment composition has a step 1 of bringing the surface to be treated of the resin material into contact with the composition at a temperature exceeding 60 ° C.
The pretreatment composition contains 10 mg / L or more of persulfate ions and 10 mg / L or more of monovalent silver ions.
A pretreatment method of electroless plating characterized by the above. An electroless plating method for a resin material,
(1) Step 1 for bringing the surface to be treated of the resin material into contact with the pretreatment composition at a temperature exceeding 60 ° C., and (2) bringing the surface to be treated for the resin material into contact with an electroless plating solution. Step 2
The pretreatment composition contains 10 mg / L or more of persulfate ions and 10 mg / L or more of monovalent silver ions.
An electroless plating method characterized by the above.   The electroless plating method according to claim 5, wherein the electroless plating solution contains a reducing agent having catalytic activity for silver.