JP6498617B2 - Brightening agent for electro nickel plating, electro nickel plating solution, electro plating method, plated product, and nickel elution prevention method - Google Patents

Description

  The present invention relates to a brightener for electro nickel plating, an electro nickel plating solution, an electro plating method, a plated product, and a nickel elution prevention method.

Conventionally, copper or copper alloy materials have been widely used for water supply equipment such as faucet fittings, water meters, and water heater components, and these outer surfaces are plated with a base for purposes such as decorativeness, corrosion resistance, and wear resistance. In many cases, nickel plating is applied, and chromium plating is further applied as finish plating. These nickel plating and chrome plating are often plated by a well-known electroplating method, and the plating is mainly deposited on the outer surface of the water supply device, but the plating is also attached to a part of the inner surface. This critical current density of the electroplating (upper and lower limits of the current density to generate a normal film) is different from the metal species (1~30A / dm ² in chromium plating, the nickel plating 0.05~10A / dm ² In addition, since the oxidation-reduction potential also varies depending on the metal species, there is a difference in the throwing power of the plating. Specifically, nickel is relatively reduced metal easily be reduced to the metallic state at a current density of 0.05 A / dm ² or more ^{(Ni 2+ + 2e - → Ni} , -0.250V vs.NHE). On the other hand, the current density required to reduce chromium having a low potential is 1 A / dm ² (Cr ³⁺ + 3e ⁻ → Cr, −0.744 V vs. NHE). For example, when the outer surface of a pipe-shaped part is plated, nickel plating deposits up to the inside of the part, but chromium plating deposits only up to the vicinity of the opening. Accordingly, nickel is exposed inside the pipe-shaped component. In the water supply device, a wide variety of water is used for the internal water passage, and nickel deposited in the water passage may be eluted due to water quality factors such as pH, water temperature change, and physicochemical factors such as water flow. Since nickel affects the human body, it is desirable to avoid exposing the nickel plating to the water passage as much as possible to prevent elution of nickel into water.

  In order to avoid nickel plating from adhering to the inner surface, for example, a method of blocking the water passage with a masking method, such as plugging the opening, can be considered. However, the shape of the water supply device is often complicated, and it is unrealistic because the work load is large and the efficiency is poor.

  As another method for avoiding nickel plating from adhering to the inner surface, for example, in Patent Document 1, at least nickel plating is applied to a water supply device made of copper or copper alloy, and then chromium plating is dissolved. There is described a method of removing nickel plating protruding from the chromium plating by immersing the nickel chromium plated water supply device in a solution that dissolves the nickel plating. However, in the method described in Patent Document 1, the nickel plating protruding from the chromium plating cannot be effectively removed, and the nickel plating remains in the water passage, so that the elution of nickel is completely prevented. difficult. Moreover, there is a possibility that the chrome plating is dissolved by removing nickel under excessive processing conditions, or the underlying nickel plating is dissolved while leaving the chrome plating, resulting in plating swelling.

JP 2002-155391 A

  The present invention has been made in view of the above-described problems of the prior art, and its main purpose is that when nickel plating and chrome plating are applied to the outer surface of the water supply device, the nickel plating is applied to the inner surface of the water supply device. It is an object of the present invention to provide a brightening agent for electrolytic nickel plating that can prevent precipitation, and an electrolytic nickel plating solution containing the brightening agent.

  The inventors of the present invention have intensively studied to achieve the above-described object. As a result, by adding a compound having an acryloyl group or a methacryloyl group as a brightener to the nickel plating solution, the lower critical current density of nickel plating can be controlled, and the plating is deposited on the inner surface of the object to be plated. I found that I can prevent it. The present invention has been completed as a result of further studies based on such findings.

That is, the present invention relates to the brightening agent for electrolytic nickel plating, the electrolytic nickel plating solution, the electroplating method, the plated product, and the nickel elution preventing method described in the following items 1 to 6.
Item 1. A brightener for an electronickel plating solution comprising a compound having an acryloyl group or a methacryloyl group.
Item 2. The compound having the acryloyl group or methacryloyl group is methoxyethyl acrylate, hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, ethyl carbitol acrylate, diacetone acrylamide, methoxyethyl methacrylate, hydroxyethyl methacrylate, tetrahydrofurfuryl methacrylate, ethyl carbitol methacrylate. The brightening agent for an electronickel plating solution according to Item 1, which is at least one selected from the group consisting of diacetone methacrylamide.
Item 3. 3. An electrolytic nickel plating solution containing the brightening agent for an electrolytic nickel plating solution according to item 1 or 2.
Item 4. 4. An electroplating method in which a nickel plating film is formed by bringing the electronickel plating solution according to item 3 into contact with an object to be plated, and a chromium plating film is formed on the nickel plating film.
Item 5. 5. A plated product obtained by plating the surface of an object to be plated by the electroplating method according to item 4.
Item 6. A nickel plating film is formed by bringing the electrical nickel plating solution according to Item 3 into contact with a water supply device, and nickel is eluted from the inside of the water supply device by forming a chromium plating film on the nickel plating film. A method for preventing nickel elution.

  By adding the brightening agent for electro nickel plating of the present invention (compound having an acryloyl group or a methacryloyl group) to the nickel plating solution, the lower critical current density of nickel plating can be controlled. It is possible to prevent the plating from being deposited on the inner surface of the plated product. Therefore, when using the nickel electroplating solution and the chromium plating solution containing the brightener and plating the outer surface of the water supply device in this order, it is possible to prevent nickel plating from depositing inside the water supply device. Nickel can be prevented from eluting from the inside of the instrument.

  Hereinafter, the brightener for electro nickel plating, the electro nickel plating solution, the electro plating method, the plated product, and the nickel elution preventing method of the present invention will be specifically described.

  The brightener for electro nickel plating of the present invention is a brightener added to an electro nickel plating solution used when a nickel film is formed on an object to be plated (to-be-plated) by electroplating. By adding the brightening agent for electro nickel plating of the present invention to the nickel plating solution, the lower critical current density of nickel plating can be controlled, and thereby the throwing power of nickel plating can be lowered. As a result, it is possible to prevent plating from being deposited on the inner surface water passage of the water supply device by performing the base plating of the water supply device using the electro nickel plating solution containing the brightening agent for electro nickel plating.

The bright additive for electrolytic nickel plating of the present invention has an acryloyl group (CH ₂ ═CH—C (═O) —) or a methacryloyl group (CH ₂ ═C (—CH ₃ ) —C (═O) —). It is characterized by including a compound. As a compound having an acryloyl group or a methacryloyl group, for example, hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, n -Octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, isobornyl (meth) acrylate, Tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, ethyl cal Tall (meth) acrylate (ethoxyethoxyethyl (meth) acrylate), methoxyethyl (meth) acrylate, methoxytriethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, (2-methyl-2-ethyl-1, 3-difunoxolan-4-yl) methyl (meth) acrylate, (3-ethyloxetane-3-yl) methyl (meth) acrylate, cyclic trimethylolpropane formal (meth) acrylate, 1,4-butanediol di (meth) Acrylate, 1,6-hexanediol (meth) acrylate, 1,9-nonanediol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, bispha AEO 3.8 mol adduct di (meth) acrylate, bisphenol A diglycidyl ether (meth) acrylic acid adduct, trimethylolpropane tri (meth) acrylate, tripentaerythritol (meth) acrylate and mono and pentaerythritol (meth) ) A mixture of acrylate and polypentaerythritol (meth) acrylate, condensate of pentaerythritol and (meth) acrylic acid, trimethylolpropane EO 3.5 mol adduct tri (meth) acrylate, polybutadiene-terminated di (meth) acrylate, Hydrogenated polybutadiene-terminated di (meth) acrylate, tetrahydrofurfuryl alcohol (meth) acrylic acid multimer ester, ethoxyethoxyethanol (meth) acrylic acid multimer ester, 1,6-hexanedio (Meth) acrylic acid multimeric ester, 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-tetrafluoropropyl (meth) acrylate, 1H, 1H, 5H-octafluoropentyl (Meth) acrylate, 1H, 1H, 2H, 2H-tridecafluorooctyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, 1,4-cyclohexanedimethanol mono (meth) acrylate, methyl vinyl ketone, Amyl vinyl ketone, methyl (meth) acrylate, ethyl (meth) acrylate, allyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, butyl (Meth) acrylate, tetramethylene glycol di (meth) acrylate, 2,2-dimethyl-1,3-propanediol di (meth) acrylate, isoamyl (meth) acrylate, hexamethylene glycol di (meth) acrylate, pentamethylene glycol di (Meth) acrylate, 2-cyanoethyl (meth) acrylate, hexyl (meth) acrylate, decamethylene glycol di (meth) acrylate, 2-ethylhexyl (meth) acrylate, 2- (dimethylamino) ethyl (meth) acrylate, 1, 1,1,3,3,3-hexafluoroisopropyl (meth) acrylate, trimethylolpropane triacrylate, tetradecyl acrylate, hexadecyl acrylate, 2-isocyanatoethyl (meth) acrylate , 2,3-dibromopropyl (meth) acrylate, 2,2,3,4,4,4-hexafluorobutyl (meth) acrylate, 1,6-bis ((meth) acryloyloxy) -2,2, 3,3,4,4,5,5-octafluorohexane, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl (meth) acrylate, diacetone (Meth) acrylamide etc. are mentioned. Here, “(meth) acrylate” means acrylate or methacrylate, and “(meth) acrylic acid” means acrylic acid or methacrylic acid. These compounds can be used individually by 1 type or in mixture of 2 or more types. Among these compounds, methoxyethyl acrylate, hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, ethyl carbitol acrylate, diacetone acrylamide, methoxyethyl methacrylate, hydroxyethyl methacrylate, tetrahydrofurfuryl methacrylate, ethyl carbitol methacrylate, and diacetone Methacrylamide is preferred.

  The density | concentration of the brightener for electro nickel plating of this invention is not specifically limited. For example, it is preferably 0.001 g / L or more and 100 g / L or less, and more preferably 0.1 g / L or more and 50 g / L or less. By setting the concentration of the brightening agent for electro nickel plating of the present invention within the above range, the lower critical current density of nickel plating is controlled to suppress the precipitation of nickel plating and to obtain a nickel plating film having excellent gloss. Can do.

  There are no particular limitations on the type of electro nickel plating solution to which the brightening agent for electro nickel plating of the present invention is added, and conventionally known electro nickel plating solutions can be used. As such an electro nickel plating solution, specifically, a so-called Watt bath containing nickel sulfate, nickel chloride, boric acid, etc., a nickel sulfamate bath containing nickel sulfamate, a so-called strike bath (wood bath) containing nickel chloride Etc. Various nickel baths including nickel monohydroxide, nickel carbonate, nickel acetate, and the like can also be used. Also. As long as the effects of the present invention are not impaired, plating-forming metal salts such as phosphorus ions, iron ions, cobalt ions, tin ions, zinc ions, and tungsten ions may be included in addition to the nickel salts.

  Hereinafter, the nickel electroplating solution will be described taking a Watt bath as an example. As the electric nickel plating solution, a plating solution containing nickel sulfate, nickel chloride, and boric acid can be used.

  As nickel sulfate, for example, nickel sulfate hexahydrate can be used. The content of nickel sulfate in the electronickel plating solution is preferably 240 g / L or more and 320 g / L or less as nickel sulfate hexahydrate. If the content of nickel sulfate hexahydrate in the plating solution is less than 240 g / L, the appearance of the plating film may be clouded and burnt. If the content of nickel sulfate hexahydrate in the plating solution is more than 320 g / L or less, the specific gravity of the plating solution increases, which may cause pits.

  As nickel chloride, for example, nickel chloride hexahydrate can be used. The content of nickel chloride in the electronickel plating solution is preferably 35 g / L or more and 50 g / L or less as nickel chloride hexahydrate. If the content of nickel chloride hexahydrate in the plating solution is less than 35 g / L, nickel used as the anode plate is passivated and nickel is insolubilized, which may inhibit the plating reaction. If the content of nickel chloride hexahydrate in the plating solution is more than 50 g / L, the internal stress of the plating film may increase.

  Boric acid is added to the electro nickel plating solution in order to suppress fluctuations in pH. The content of boric acid in the electronickel plating solution is preferably 30 g / L or more and 50 g / L or less.

  The electronickel plating solution contains the above-described brightener for electronickel plating as an additive. Additives other than the brightener for electrolytic nickel plating can be added to the electrolytic nickel plating solution as necessary. Examples of other additives include a primary brightener, a secondary brightener, a pit inhibitor, a complexing agent, and the like. The primary brightener functions as a stress suppressor that reduces the tensile stress of the plating film. For example, benzenesulfonic acid, p-toluenesulfonamide, saccharin, sulfonamide, sulfonimide, naphthalenesulfonic acid, sulfonic acid, alkyl A sulfonic acid etc. are mentioned. The secondary brightener functions to brighten and fill small scratches on the plating film, that is, to give a leveling effect. For example, formaldehyde, allylsulfonic acid, 2-butyne-1,4-diol, ethyl And cyanhydrin. The pit preventing agent lowers the surface tension of the plating bath to improve wettability and prevent pits, and examples thereof include surfactants such as sodium lauryl sulfate. The complexing agent strongly coordinates with the deposited metal to prevent the formation of hydroxide precipitates, and examples thereof include organic acids and aminocarboxylic acids.

  Since a nickel-plated film having a higher gloss can be obtained, it is preferable to add a primary brightener and a secondary brightener to the electronickel plating solution in addition to the brightener for electronickel plating of the present invention.

  The pH of the electro nickel plating solution is preferably 1.5 or more and 6 or less.

  The method for forming a nickel film using the electric nickel plating solution of the present invention is not particularly limited, and can be performed by a known electric nickel plating method. After performing a known plating pretreatment, a nickel plating film can be formed by bringing the object to be plated into contact with an electric nickel plating solution until nickel plating having a required thickness is obtained. In the present invention, there are no particular limitations on the plating conditions for performing nickel plating, and the conditions may be adopted as appropriate according to the type of nickel plating solution used.

  For example, with regard to the bath temperature during the plating operation, when the bath temperature is low, the conductivity decreases, the current density decreases, the plating rate decreases, and gloss unevenness occurs. Moreover, boric acid does not melt | dissolve but precipitates as a crystal | crystallization. If the bath temperature is too high, the heat resistance of the material of the tank or equipment may be affected. Therefore, an appropriate bath temperature may be determined in consideration of these points. The bath temperature is preferably in the range of about room temperature to 70 ° C., more preferably about 40 ° C. to 60 ° C.

The cathode current density may be appropriately determined according to the plating solution to be used, the type of the object to be plated, and the like, and is preferably about 0.05 A / dm ² or more and 10 A / dm ² or less.

  As the anode, either a nickel plate alone or an insoluble anode can be used. An object to be plated, which will be described later, is used for the cathode.

  The film thickness of the nickel plating film is not particularly limited, and can be, for example, 1 μm or more.

  It is preferable that the outer surface of the water supply device is subjected to nickel plating and then further subjected to chromium plating as finish plating.

  Chromium plating can be performed using a conventionally used chromium plating solution.

  The chromium plating solution may contain either hexavalent chromium or trivalent chromium as a chromium component. From the viewpoints of the working environment, the efficiency of wastewater treatment, etc., it is preferable to use trivalent chromium with little toxicity. Furthermore, trivalent chromium is preferable from the viewpoint of salt resistance.

  When hexavalent chromium is used, a conventionally known hexavalent chromium plating bath such as a sergeant bath, a fluoride bath, an organic acid bath, or the like can be used.

The Sargent bath is composed of a plating solution containing about 150 g / L to 400 g / L of chromic anhydride (CrO ₃ ) and about 1 g / L to 5 g / L of sulfuric acid.

Fluoride is added to the plating solution used for the fluoride bath. Examples of the fluoride include a fluoride compound, a silicofluoride compound, a borofluoride compound, and hydrofluoric acid. For example, it comprises a plating solution containing about 200 g / L of chromic anhydride (CrO ₃ ), about 1.2 g / L of sulfuric acid and about 1.6 g / L of sodium fluorosilicate.

An organic acid is added to the plating solution used in the organic acid bath. Examples of the organic acid include methanesulfonic acid, methanedisulfonic acid, methanetrisulfonic acid, and benzenesulfonic acid. For example, it consists of a plating solution containing about 250 g / L of chromic anhydride (CrO ₃ ), about 2.5 g / L of sulfuric acid, and an appropriate amount of organic acid.

  When using trivalent chromium, the trivalent chromium plating solution may be a plating solution made of an aqueous solution containing a water-soluble trivalent chromium compound as a chromium component, and the specific composition is not particularly limited. In general, in addition to water-soluble trivalent chromium compounds, pH buffering agents are added to trivalent chromium plating baths to prevent the formation of chromium hydroxide and the like due to pH increase at the cathode reaction interface. Furthermore, various additives such as a complexing agent, a conductive salt, and a brightening agent are added. In the present invention, any trivalent chromium plating solution containing such various additives can be used.

  The water-soluble trivalent chromium compound contained in the trivalent chromium plating solution is not particularly limited as long as it is a water-soluble compound containing trivalent chromium as a chromium component, and chromium sulfate, chromium chloride, chromium nitrate, chromium acetate, etc. Can be illustrated. These water-soluble trivalent chromium compounds can usually be used singly or in combination of two or more. About an example of the concentration of the trivalent chromium compound, the concentration of the trivalent chromium ion is about 1 g / L or more and 50 g / L or less.

  Examples of pH buffering agents include boric acid, sodium borate, and aluminum chloride. These pH buffering agents are usually added singly or in combination of two or more. The concentration of the pH buffering agent is, for example, about 10 g / L or more and 100 g / L or less.

  Examples of complexing agents include monocarboxylic acids such as formic acid and acetic acid or salts thereof; dicarboxylic acids such as oxalic acid, malonic acid, and maleic acid; or salts thereof; hydroxycarboxylic acids such as citric acid, malic acid, and glycolic acid; Etc. can be illustrated. Examples of the salts described above include alkali metal salts such as sodium salts and potassium salts, ammonium salts, and the like.

  Examples of the conductive salt include alkali metal salts such as sodium sulfate, sodium chloride, potassium chloride and potassium sulfate; ammonium salts such as ammonium sulfate and ammonium chloride.

  Examples of brighteners include saccharin, saccharin sodium, naphthalene sulfonic acid, sodium naphthalene sulfonate, butynediol, and propargyl alcohol.

  These additives can usually be used singly or in combination of two or more. The concentration of these additives is not particularly limited. For example, the complexing agent is 5 g / L or more and 200 g / L or less, the conductive salt is 10 g / L or more and 300 g / L or less. The brightener is about 0.5 g / L or more and 20 g / L or less.

  The pH of the trivalent chromium plating solution may be the same as that during normal trivalent chromium plating, and the pH is usually in the range of 2 to 5.

  In the present invention, the plating conditions for performing chromium plating are not particularly limited, and the same conditions as normal plating conditions may be adopted according to the type of chromium plating solution to be used.

  For example, when the bath temperature during plating is low, the throwing power is improved but the film-forming speed tends to decrease. Conversely, when the bath temperature is high, the film-forming speed is improved but low. Since the throwing power to the current density region tends to decrease, an appropriate bath temperature may be determined in consideration of this point. The bath temperature is preferably in the range of about 30 ° C to 60 ° C.

The cathode current density may be appropriately determined according to the plating solution to be used, the type of the object to be plated, and the like, and preferably about 1 A / dm ² or more and 20 A / dm ² or less.

  When the formed chromium plating film is a single layer, either a trivalent chromium plating film or a hexavalent chromium plating film may be used. However, since the hexavalent chromium plating solution itself has a chromate effect, when trivalent chromium plating is applied, nickel elution from the inside of the object to be plated is compared to when hexavalent chromium plating is applied. The amount becomes higher.

  Moreover, two layers of chromium plating films can be formed by forming a hexavalent chromium plating film on the trivalent chromium plating film.

  If necessary, immersion chromate treatment or electrolytic chromate treatment can be performed on the chromium plating film.

  Therefore, the present invention provides an electroplating method in which a nickel plating film is formed by bringing the above-described electro nickel plating solution into contact with an object to be plated, and a chromium plating film is formed on the nickel plating film. it can. Moreover, the plated product which plated the surface of the to-be-plated object with the electroplating method mentioned above can also be provided. Examples of the method for producing the plated product include a method in which a nickel plating film is formed by bringing the above-described electric nickel plating solution into contact with an object to be plated, and a chromium plating film is formed on the nickel plating film. By plating the surface of the object to be plated by the electroplating method described above, the above-described plating film is formed on the surface of the object to be plated. A water supply apparatus is suitably used as the object to be plated. Examples of the water supply device include parts through which water flows, such as a faucet fitting, a water meter, and a water heater member. Examples of the material for the water supply device include copper and copper alloys such as bronze and brass.

  From the above, the present invention forms a nickel plating film by bringing the above-described electric nickel plating solution into contact with a water supply device, and forms a chromium plating film on the nickel plating film, thereby forming nickel from the inside of the water supply device. It is possible to provide a nickel elution prevention method for preventing the elution of leaching. Using the nickel electroplating solution and the chromium plating solution containing the brightening agent for electronickel plating of the present invention and plating the outer surface of the water supply device in this order, the throwing power of nickel plating is lowered, and the nickel inside the water supply device is reduced. Since plating can be prevented from being deposited, it is possible to prevent nickel from eluting from the inside of the water supply apparatus.

  Hereinafter, the present invention will be described in more detail with reference to examples.

Test example 1 (Hull cell test)
Nickel sulfate hexahydrate _{(NiSO 4 · 6H 2 O)} 280g / L, nickel chloride hexahydrate _{(NiCl 2 · 6H 2 O)} 45g / L and boric acid _{(H 3} BO 3) plating containing 40 g / L The brightener, primary brightener (Okuno Pharmaceutical Co., Ltd., trade name: TOP DuNC BN-1) or secondary brightener (Okuno Pharmaceutical Co., Ltd., trade name) listed in Tables 2 to 4 : TOP DuNC BN-2) was added in the amounts listed in Tables 2 to 4 and mixed to prepare nickel plating solutions of Examples 1 to 29 and Comparative Examples 1 to 5.

  A brass plate (60 × 200 mm) was used as a test piece, and after pretreatment, nickel plating was performed using the plating solutions of Examples 1 to 29 and Comparative Examples 1 to 5.

Specifically, as a pretreatment, the test piece is immersed for 5 minutes in an aqueous solution (liquid temperature 55 ° C.) in which an alkaline degreasing agent (Okuno Pharmaceutical Co., Ltd., trade name: A-screen 850) is diluted to a concentration of 50 g / L. The degreasing cleaning was performed. After washing with water, an electrolytic degreasing agent (Okuno Pharmaceutical Co., Ltd., trade name: Top Cleaner E) was diluted to a concentration of 50 mL / L, and the test piece was immersed in an aqueous solution to which sodium hydroxide (50 g / L) was added. Cathodic electrolytic degreasing treatment was performed at room temperature at a current density of 5 A / dm ² for 30 seconds. After washing with water, the test piece was immersed in an aqueous solution obtained by diluting an acid active solution (Okuno Pharmaceutical Co., Ltd., trade name: Top Sun) to a concentration of 50 g / L, and an acid activity treatment was performed at room temperature for 30 seconds.

  After washing with water, the pretreated specimen was immersed in the plating solutions of Examples 1 to 29 and Comparative Examples 1 to 5 (solution amount: 430 mL, bath temperature: 55 ° C.). Was subjected to nickel plating for 5 minutes.

For each plating bath, the lower critical current density and the hull cell plating appearance were evaluated.
The lower limit critical current density was obtained by visually reading the lower limit current density at which the nickel plating film was deposited on the test piece using a Hull Cell (registered trademark) current density quick-view plate (manufactured by Yamamoto Kakin Tester Co., Ltd.).

  The appearance of the Hull cell plating was evaluated by visual observation of the plating appearance in the area where nickel was deposited.

Test Example 2 (Nickel dissolution test)
A brass cylindrical pipe (30 mmφ × height 53 mm, thickness 1 mm) was used as a test piece, and the following treatment was performed. First, the test piece was immersed in an aqueous solution (liquid temperature 55 ° C.) diluted with an alkaline degreasing agent (Okuno Pharmaceutical Co., Ltd., trade name: A-screen 850) to a concentration of 50 g / L for 5 minutes for degreasing washing. . After washing with water, an electrolytic degreasing agent (Okuno Pharmaceutical Co., Ltd., trade name: Top Cleaner E) was diluted to a concentration of 50 mL / L, and the test piece was immersed in an aqueous solution to which sodium hydroxide (50 g / L) was added. Cathodic electrolytic degreasing treatment was performed at room temperature at a current density of 5 A / dm ² for 30 seconds. After washing with water, the test piece was immersed in an aqueous solution obtained by diluting an acid active solution (Okuno Pharmaceutical Co., Ltd., trade name: Top Sun) to a concentration of 50 g / L, and an acid activity treatment was performed at room temperature for 30 seconds. After rinsing with water, the above-described plating bath was used, and the test piece was nickel-plated in a state where the two openings were in the vertical direction in the plating solution (liquid temperature 55 ° C., current density 3 A / dm ² 15 minutes), and after washing with water, hexavalent chromium plating or trivalent chromium plating was performed. Hexavalent chromium plating was performed using a sergeant bath (chromic anhydride 250 g / L, sulfuric acid 2.5 g / L) at a liquid temperature of 40 ° C. and a current density of 12 A / dm ² for 3 minutes. Trivalent chromium plating was performed for 5 minutes at a liquid temperature of 40 ° C. and a current density of 8 A / dm ² using a top fine chromium bath manufactured by Okuno Pharmaceutical Co., Ltd.

  After chromium plating, the test piece was washed with water and dried with warm air using a dryer. Since plating deposits inward from the openings on both sides of the test piece (cylindrical pipe), the nickel plating depositability within the pipe (the range in which plating is deposited from the opening to the inside of the pipe) The length of the nickel plating deposited in the pipe from the opening (two places at the top and bottom) within the range of the nickel plating deposited on was measured and evaluated in total. In the measurement, the pipe was cut in half in the vertical direction, and the length of the nickel plating deposited inside the pipe was measured.

  In addition, the plated test piece was immersed in an artificial sweat (acidic and alkaline) liquid having a liquid volume of 100 ml at 40 ° C. for 24 hours. The detailed conditions of the artificial sweat test are as follows.

  After immersion for 24 hours, the elution amount of nickel was measured by ICP emission spectrometry.

  Tables 2 to 4 show the types and contents of brighteners in the nickel plating solutions of Examples 1 to 29 and Comparative Examples 1 to 5, the types of chromium plating, and the results of Test Examples 1 and 2.

  In Comparative Examples 1 to 5 not including a compound having an acryloyl group or a methacryloyl group, nickel was precipitated on the entire surface of the pipe, and thus the amount of nickel elution was large. In Examples 1 to 29 including a compound having an acryloyl group or a methacryloyl group, the lower critical current density is controlled and the nickel elution amount is reduced as compared with Comparative Examples 1 to 5 not including a compound having an acryloyl group or a methacryloyl group. did. In addition, when hexavalent chromium plating is applied as chromium plating, the nickel elution amount is lower than when trivalent chromium plating is applied. The hexavalent chromium plating solution itself has a chromate effect. Because. From these results, it is understood that nickel elution can be prevented by forming a nickel plating film with an electro nickel plating solution containing a compound having an acryloyl group or a methacryloyl group and forming a chromium plating film thereon.

Claims (5)

Electricity comprising a compound having at least one acryloyl or methacryloyl group selected from the group consisting of hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, diacetone acrylamide, hydroxyethyl methacrylate, tetrahydrofurfuryl methacrylate, and diacetone methacrylamide Brightener for nickel plating solution. An electro nickel plating solution containing the brightener for electro nickel plating solution according to claim 1 . An electroplating method in which a nickel plating film is formed by bringing the electronickel plating solution according to claim 2 into contact with an object to be plated, and a chromium plating film is formed on the nickel plating film. A plated product obtained by plating the surface of an object to be plated by the electroplating method according to claim 3 . A nickel plating film is formed by bringing the electric nickel plating solution according to claim 2 into contact with a water supply device, and nickel is eluted from the inside of the water supply device by forming a chromium plating film on the nickel plating film. A method for preventing nickel elution.