JPS6147240B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a satin plating method for satin plating using an additive that forms an organic emulsion in a plating solution. Satin plating that allows a satin-plated film with a constant appearance to be obtained by removing excessively agglomerated organic emulsion by filtration and replenishing the plating solution with additives lost due to filtration. Regarding the method.

Conventionally, as a method for obtaining a satin-like plating film, a method is known in which plating is performed using an additive that forms an organic emulsion in a plating solution. For this plating method, the temperature is 40 to 75℃.
By adding ethylene oxide and propylene oxide compounds that produce finely dispersed emulsions to the plating solution, and plating with the solution suspended by raising the solution temperature during plating, matte-like nickel electrodeposit can be obtained. How to obtain (Tokuko Sho 46-
644), a method for obtaining satin-like nickel or nickel-cobalt electrodeposit by adding a cationically active or amphoteric substance to the plating solution together with an organic anion to generate a foreign substance in the plating solution (JP-A-Sho
50-20934), etc., and each method has various advantages, and the latter method in particular can obtain satin plating in various states with excellent appearance and physical properties, and also has special It has advantages such as not requiring cooling/heating equipment and easy bath management.

However, according to studies conducted by the present inventors, in the satin plating method using additives that form an organic emulsion in the plating solution, the number of emulsion particles decreases because the organic emulsion aggregates over time. As the particle size decreases, the particle size increases, and this organic emulsion with increased particle size causes the resulting plated film to become more matte, causing the problem that the plated appearance changes over time. I found out.

For this reason, the present inventors have developed a method for performing satin plating using an additive that forms an organic emulsion in a plating solution to prevent changes in the appearance of plating over time caused by organic emulsion that aggregates and increases. As a result of intensive research into this, we found that when performing satin plating using an additive that forms an organic emulsion in the plating solution, a portion of the plating solution in the plating tank can be continuously removed. This is then sent to a filtration device, where the organic emulsion present in the plating solution that has aggregated over a certain size is continuously removed, and the filtrated plating solution is returned to the plating tank. By replenishing the plating solution with an amount of additive equivalent to the amount of emulsion removed by filtration, the appearance of the resulting satin plating film is prevented from changing over time, and a uniform satin plating film is always maintained. I found out that it can be obtained.

That is, according to the present inventors' studies, when the organic emulsion aggregates to a particle size of about 20 to 30 μm or more, the increased organic emulsion causes a change in the plating appearance. In the present invention, such increased organic emulsion is removed by filtration, and an amount of additive corresponding to the emulsion removed by filtration is replenished, that is, the emulsion that has coagulated and increased is made into a new emulsion. By replacing
Plating is carried out in such a way that there is no organic emulsion that has grown beyond a predetermined size in the plating solution in the plating tank, thereby achieving satin plating that always has a uniform appearance from the beginning to the end of the plating process. This allows a film to be obtained.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

The satin plating method according to the present invention is carried out using an additive that forms an organic emulsion in the plating solution.

In this case, any additive can be used as long as it forms an organic emulsion in the plating solution to give a satin electrodeposit. For example, it forms a finely dispersed emulsion at a temperature of 40 to 75°C. Substituted or unsubstituted ethylene oxide or propylene oxide, as formed in the electrolyte of the bath, as well as ethylene oxide-propylene oxide adduct compounds
644) etc. can be used, but the method of the present invention can be suitably adopted especially when a cationically active or amphoteric substance is used together with an organic anion (Japanese Unexamined Patent Publication No. 1983-20934). For example, Pearl Bright manufactured by Uemura Kogyo Co., Ltd. can be used.

Further, the type of plating liquid used in the present invention is not particularly limited, and is appropriately selected depending on the purpose of satin plating. For example, an acidic electrolytic nickel plating solution having a pH of 2.5 to 6, a nickel alloy plating solution such as nickel-cobalt or nickel-iron, a cobalt plating solution, a cobalt alloy plating solution, etc. are used. In this case, the plating solution may be one having a known bath composition, such as a Watt bath, a sulfuric acid bath, a high chloride bath, or a sulfamic acid bath. Furthermore, plating temperature,
Plating conditions such as current density are not particularly limited, and appropriate conditions are adopted depending on the purpose and the like.

In the plating method of the present invention, when performing satin plating using the above-mentioned additives, a part of the plating solution in the plating tank is continuously taken out and sent to the filter device, and the plating solution is transferred to the filter device. Continuously removes the organic emulsion that has aggregated over a certain size in the plating solution, returns the plating solution after filtration to the plating tank, and adds an amount equivalent to the organic emulsion removed by filtration. The plating agent is supplied to the plating solution.

That is, to explain in more detail with reference to the drawings,
The drawing shows an example of a plating apparatus used to carry out the plating method of the present invention. In the drawing, 1 is a plating tank with an overflow tank, in which a plating tank 2 and an overflow tank 3 are attached. The height of the overflow plate 2a between the overflow tank 3 and the overflow tank 3 is formed low, and the plating liquid in the plating tank 2 climbs over this overflow plate 2a and continuously overflows into the overflow tank 3. A portion of the plating tank 2 is continuously taken out from the plating tank 2. Note that 4 is a drain pipe connected to the bottom wall of the overflow tank 3 via a valve 5. In this apparatus, objects to be plated are plated in a plating tank 2.

In the above device, one end of a circulation pipe 12 in which a valve 6, a metering pump 7, a filter device 8, a valve 9, a flow meter 10, and a valve 11 are sequentially inserted is inserted into the plating liquid in the overflow tank 3. The other end of the circulation pipe 12 is inserted into the plating solution in the plating tank 2. Here, the other end of the circulation pipe 12 is connected to the top of the plating solution in a partition chamber 13 formed between a side wall 2b facing the overflow plate 2a and a partition plate 2c provided near the side wall 2b. It is equipped with an end outlet. The lower end of the partition plate 2c is separated from the bottom wall of the plating tank 2 by a predetermined distance, thereby forming a plating liquid communication section 14, through which the plating liquid in the partition chamber 13 is transferred. It is designed to flow into the plating chamber 2' of the plating tank 2. Here, 15 is a drain pipe connected to the circulation pipe 12 downstream of the filtration device 8 via a valve 16.

Furthermore, 17 is an additive storage tank, and this additive storage tank 1
7 is connected to one end of a supply pipe 20 in which a valve 18 and a metering pump 19 are successively installed. At the other end of this replenishment pipe 20, an additive is disposed in the partition chamber 13 in close proximity to the partition plate 2c, and the addition port at the tip thereof is arranged slightly above the lower end of the partition plate 2c in the plating solution. The other end of the pipe 21 is removably connected.

In addition, in the above device, the pump 7 is 1
It is preferable to use a pump that can pump 10 to 100% of the plating solution per hour. In this case, the type of pump is not particularly limited, and a type that uses a gland packing or mechanical seal can also be used, but in the present invention, it is avoided to flow the plating liquid in a state where air is involved. In this respect, sealless pumps are preferred.

Further, the filtration device 8 is preferably made of a material capable of selectively removing particles with a particle size of 10 μm or more, more preferably 20 to 30 μm or more, but a type that can remove particles with a particle size of 0.5 μm or more may also be used. The passing device 8 is
For example, cartridge-type ones, cloth-type ones, and ones coated with super-aiding agents such as activated carbon.
An appropriate one is used depending on the request. When using a cartridge type material, use one with the desired mesh size and a particle size of 20 to 30 μm.
It is possible to selectively remove aggregated particles of m or more, but if the plating time becomes long, the material will gradually become clogged.
Agglomerated particles smaller than the above particle size are also removed, and if additives are continuously replenished at a constant addition rate, the organic emulsion in the plating solution may become insufficient and the appearance of the plated product may change. In order to prevent this, it is preferable to install at least two filtration devices and use them alternately to clean the material after use and to keep the material free of clogging at all times. In addition, when activated carbon is used as a super-aiding agent, it is preferable to replenish the additive in an amount corresponding to the amount of the emulsion, since the emulsion of small particles that do not need to be removed will be removed to some extent along with the particles that have aggregated and increased in size. In this case, it is preferable to minimize the amount of plating solution circulated to reduce the amount of small particle emulsion removed and to minimize the amount of additive replenishment. When activated carbon is used in this way, the amount of emulsion particles removed changes less over time, so
The amount of emulsion in the plating solution is kept almost constant by replenishing the additive at a constant rate, so that there is little change in the appearance of the plating.

In addition, when using a plating tank 2 with a capacity of 500 to 2000, for example, the flow meter 10 should be 70
It is preferable to use one that can measure up to 2000/hr.

When plating is performed using the above device, the valves 6, 9, and 11 are opened and the valve 16 is closed, and the metering pump 7 continuously sucks the plating liquid in the overflow tank 3 into the circulation pipe 12. The plating solution is passed through the filtration device 8 to remove the organic emulsion present therein that has aggregated to a certain size or more, and the plating solution after the filtration is passed through the outlet at the other end of the circulation pipe 12. Let it blow out,
This is to be returned to the plating tank 2. In this case, the amount of plating liquid circulated is 10 to 10 times the amount of plating liquid in the plating tank 2 per hour while checking with the flow meter 10.
It is preferable to adjust so that 100%, especially 15 to 50%, of the plating solution is circulated. Further, it is preferable to use a cathode rocker or the like for stirring.

Furthermore, when plating is performed using the above device,
While performing the above operations, the additive in the additive storage tank 17 is continuously added to the plating solution in the plating tank 2. In this case, the valve 18 is opened and the additive in the additive storage tank 17 is sucked by the metering pump 19,
It is made to flow through the supply pipe 20 and the addition pipe 21 and is discharged from the addition port at the tip of the addition pipe 21. Here, the amount of additive added varies depending on the type of additive used, but in any case, it is an amount that can compensate for the organic emulsion removed by the filtration device 8 and the organic emulsion consumed by plating. It is necessary.

In the above device, the plating solution is continuously pumped up by the pump 7, passed through the filter device 8 to remove the increased organic emulsion therein, and returned to the plating solution in the plating tank 2. By continuously replenishing the plating solution with additives, plating is performed without the increased organic emulsion present in the plating solution, so the plating process is uniform from start to finish. A tanned film is obtained. In addition, by adopting a continuous automatic system for replenishing additives, there is no inconvenience such as changes in the color tone of the plating film before and after replenishment, unlike the conventional method of replenishing in batches at regular intervals. In addition, stirring the plating solution with a stirring rod when replenishing eliminates the need for additional effort.

It should be noted that plating is carried out continuously while replenishing such additives.
According to the above-mentioned replenishment method, even if plating is performed while replenishing the additive, uniform plating will be achieved and the plating film will not be adversely affected in any way.

Additionally, if air gets mixed into the plating solution during plating work, significant pitting may occur on the underside of the object to be plated. Therefore, it is preferable to prevent air from getting mixed into the plating solution. However, in the above device, the outlet at the other end of the circulation pipe 12 is placed in the plating liquid at the upper part of the partition chamber 13 formed by the partition plate 2c, and the blown out plating liquid flows inside the partition chamber 13. The plating liquid communication portion 14 descends.
, and reaches the position of the object to be plated in the plating chamber 2', so even if air is mixed in the returned plating liquid, the air rises inside the partition 13 and is removed from the partition 13. This allows for good degassing. In addition, in order to prevent air from being mixed into the circulating plating solution, the circulation pipe 12 should be
It is desirable to remove as much air as possible from the piping by flowing the plating liquid inside the piping at maximum flow rate.

Furthermore, in the above device, the plating liquid returned as described above descends in the partition chamber 13, passes through the plating liquid communication part 14, and is gently deposited at the position of the object to be plated in the plating chamber 2'. Since the plating moves in a straight line, the object to be plated is not hit by a strong liquid stream, and therefore even mirror-surfaced objects such as plastics can be plated well.

Further, in the above device, the addition port at the tip of the addition pipe 21 is arranged slightly above the lower end of the partition plate 2c in the partition chamber 13 located on the opposite side of the overflow tank 2, and the addition port and the overflow plate 2a
and are at opposite positions, the replenished additive passes through the plating liquid communication portion 14 and rises in the plating liquid toward the upper end of the overflow plate 2a, being mixed with the plating liquid, and thus the added additive is mixed with the plating liquid. The agent is uniformly dispersed and good satin plating is achieved. .

Furthermore, in the above device, the addition pipe 21 is removably connected to the supply pipe 20, which is extremely convenient for cleaning the addition pipe.

In the above device, the open portion at the other end of the circulation pipe 12 is formed as a blowout port, but a blowout pipe having a large number of blowholes or the like may be attached to the other end of the circulation pipe 12, or the addition pipe may be connected to one end. Although this is a book, it may be composed of multiple books. Furthermore, a plating liquid communication hole may be formed in the partition plate 12 so that the plating liquid can flow through the hole.

As described above, according to the satin plating method of the present invention, in the method of performing satin plating using an additive that forms an organic emulsion in the plating solution, part of the plating solution in the plating tank is The sample is continuously taken out and sent to a filtration device, which continuously removes the organic emulsion present in the plating solution that has aggregated over a certain size, and the plating solution after the filtration is filtered. Along with returning it to the tank,
By replenishing the plating solution with an amount of additive corresponding to the organic emulsion removed by filtration, a uniform plating film can be obtained from the beginning to the end of the plating operation.

EXAMPLES Hereinafter, the present invention will be specifically explained by showing Examples and Comparative Examples.

Examples and Comparative Examples A satin nickel plating solution having the following composition was prepared.

Nickel sulfate hexahydrate 450g / Nickel chloride hexahydrate 35g / Boric acid 30g / Brightener saccharin 2g / Additive cetyltrimethylammonium chloride 80g / 2-ethylhexyl sulfate
50g/PH 4.4 Next, using nickel plating liquid 1000 with the above composition, satin nickel plating was applied to a number of U-shaped brass plates coated with semi-bright nickel plating film under the following plating conditions. It went on for 8 hours straight. In this case, a plating device similar to that shown in the drawings was used, and plating was performed on each warp under the following operating conditions, and the finish of the satin nickel plating was evaluated. The above plating device is F5DE manufactured by Sanshin Seisakusho Co., Ltd.
Using a molding machine, the overbody was coated with diatomaceous earth, and the top was further coated with activated carbon. This filter is capable of removing particles having a particle size of 2 to 3 μm or more.

Plating conditions Stirring: Vertical vibration method using a cathode rocker Solution temperature: 50°C Cathode current density: 3.5 A/dm ² Plating time: 8 minutes Example Operating conditions: Pump 7 is activated to dispense the plating solution
The plating solution was continuously circulated at a circulation rate of 200/hour, filtered by filter 8, and cetyltrimethylammonium chloride aqueous solution (100 mg/minute) was continuously replenished to the plating solution by pump 19 at an addition rate of 23 ml/minute. . In addition, at 4 hours, 2-ethylhexyl sulfate aqueous solution (1 g/) was added at 0.10
It was replenished in batches at an addition amount of ml/ml.

Plating finish: A satin nickel plating film with a uniform appearance was always obtained from the beginning to the end of the plating process.

Comparative example Operating conditions: Pump 7 is not operated (plating solution is not circulated), and cetyltrimethylammonium chloride aqueous solution (3 g/) is added every 2 hours.
The plating solution was replenished in batches at a rate of 0.07 ml. In addition, at 4 hours, 2-ethylhexyl sulfate aqueous solution (1 g/) was replenished in batches at an addition amount of 0.10 ml/.

Plating finish: As time passed after adding the additive, the satin plating gradually became rougher, more matte, and whiter.

From the above results, it was confirmed that according to the satin plating method of the present invention, a uniform satin nickel plating film was always obtained from the beginning to the end of the plating operation.

[Brief explanation of the drawing]

The drawing is a schematic cross-sectional front view showing an example of a plating apparatus used for carrying out the satin plating method of the present invention. 1...Plating device, 2...Plating tank, 8...
filtration device, 12...circulation pipe, 17...additive storage tank.

Claims (1)

[Claims] 1 In a method of performing satin plating using an additive that forms an organic emulsion in a plating solution, a part of the plating solution in the plating tank is continuously taken out and sent to a filter device, and this The device continuously removes the organic emulsion present in the plating solution that has aggregated over a certain size, and returns the plating solution after filtration to the plating tank. A satin plating method characterized in that an amount of an additive is supplied to a plating solution.