JPS5856037B2 - Acidic Ni electroplating bath - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an acidic Ni electroplating bath, comprising:
In particular, the present invention provides an acidic Ni electroplating bath suitable for forming a Ni plating film with a satin appearance.

BACKGROUND ART Conventionally, in order to reduce reflection on the surfaces of various photographic devices, calculators, typewriters, etc., anti-glare plating is often applied to the surfaces to give them a finely roughened, so-called satin appearance.

As this plating film, for example, 1 manufactured by Nishilite Co., Ltd.
"Satilite Nickel" is obtained by electroplating inorganic insoluble fine particles suspended in a Ni plating bath by air stirring.

However, although the above-mentioned fine particles are eutectoided with Ni on the plated object to obtain a satin appearance, dedusting treatment is required to remove the above-mentioned fine particles deposited on the surface of the plating film before the next step of plating. to be,
There are drawbacks such as fingerprints being left on the plated film when you touch it.

Another example is "velor nickel" manufactured by Schering.

According to this method, -CH2-CH2-0)n- and -(
A nonionic surfactant whose main structural unit is CH2-CH2CH20)n- is added to the Ni plating bath to obtain a satin appearance by utilizing its cloud point phenomenon. Since surfactants are easily soluble at low temperatures and difficult to dissolve at high temperatures, they aggregate very quickly, and therefore the plating solution must be regenerated by cooling and heating.

That is, for example, after only about 2 hours have passed, a change is observed in the state of the plating, and the appearance of the plating film changes.

Therefore, elaborate equipment is required to regenerate the plating solution, and it is very difficult to obtain a satin appearance with a stable particle size.

Another example is to roughen the surface of the material or the plating film of Ni or the like by sandblasting, but this method involves mechanical treatment, which increases the cost.

The present invention aims to correct the above-mentioned deficiencies.

That is, the acidic Ni electroplating bath according to the present invention is a water or alcohol soluble polymer with a molecular weight of 10.0.
00 or more borivinylpyrodrine, molecular weight 500-5,
000(7), J” reester and molecular weight 500-5
It is characterized in that it contains at least one polymer ITn selected from the group consisting of polythiol esters of 9/1 to 10 g/l and a base brightener of 0.1 g/l to 30 g/l, respectively.

With this configuration, a strong, stable, and uniform satin appearance can be obtained at low cost without requiring a special plating bath reconditioning device.

Next, each of the above-mentioned components will be explained.

(1) Polyvinylpyrrolidone Polyvinylpyrrolidone has the general formula It is something that

The polyvinylpyrrolidone added to the plating bath has a molecular weight of 10,000 or more, which facilitates obtaining a satin appearance.

(2) Poly'''7te''o-c This polyester has an 11 structure in its main chain, and is produced by polymerization of a polybasic acid such as phthalic acid or adipic acid and a polyhydric alcohol such as a diol or triol. soluble in water or alcohol obtained by
Those having a molecular weight of 500 to 5,000 are used.

(3) Polythio-17th edition S- ester has 11 in its main chain, is soluble in water or alcohol obtained by polymerization of the above polybasic acid and thioalcohol, and has a molecular weight of 50
0 to 5,000 is used.

The amount of each of the above-mentioned polyvinylpyrrolidone, polyester, and polythiol ester added is 1 pprn (11n
g/l) to 10,000 ppm (10 g/l).

If the amount added is less than 1 ppm, the satin appearance will become weak, and if the amount added is less than 10.0 ppm, the satin appearance will become weak. If it exceeds OOOppm, the agglomeration rate becomes too high, resulting in poor emulsion stability, and the agglomerates make it difficult to make the surface roughness uniform, resulting in only a resin-like, non-uniform satin appearance.

Further, the reason why a water- or alcohol-soluble material is added is that it is easily dissolved in a plating bath and that it can be removed by washing with a degreasing liquid or alcohol after plating.

Note that two or more of the above-mentioned components may be added at the same time, but in this case, the total amount added is still 1 p pr
It is preferable to set it to rr-1-0,000 ppm.

In addition, as usual basic brighteners in the above-mentioned plating bath, for example, sulfonic acids such as mono-, di- or trinathalene sodium disulfonate, sodium trisulfonate, sulfonamides or sulfonimides such as saccharin soda, para-toluene sulfonamide, etc. is preferably added.

This addition not only imparts gloss to the plated film, but also prevents stress from being applied to the plated body during plating, making it possible to obtain a stable plated body.

This basic brightener is necessary to obtain a satin appearance, and the amount added is preferably 0.1 g/771 to 30 g/l, more preferably 0.5 g/l to 10 g/l.

That is, if it is less than 0.1 g/l, it is difficult to obtain a satin appearance, and if it exceeds 30 g/l, it becomes too glossy and the stability of the emulsion becomes poor.

The amount of this brightening agent added varies depending on the desired satin appearance; for example, to obtain a glossy appearance, the amount of each of the above-mentioned components should be as low as 5 to 20 ppm, and the amount of the basic brightening agent should be increased. I can do it.

Furthermore, a cationic surfactant such as a quaternary ammonium salt may be added as a stabilizer to the above-mentioned plating bath to maintain the stability of the bath, if necessary.

In the above-mentioned plating bath, the agglomeration rate of each component is very slow, so a very stable emulsion is formed. For example, even if the plating bath is maintained for more than a week, the satin appearance that is formed will remain the same as before. It's no different from anything else.

Therefore, there is no need for special regeneration treatment of the plating bath as in the past, and it can be maintained using the same maintenance method as a normal plating bath, such as filtration of the plating bath and replenishment of each component. It becomes possible to obtain a stable satin appearance at a low cost.

For plating, a Watt bath or a sulfamic acid bath can be used as the plating bath, and the objects to be plated include polished brass plates and A plated with electroless plating.
BS resin or the like can be used, and the decorative value can be increased by applying decorative plating such as 5n-Co bright plating to the Ni-plated surface with a satin appearance.

Next, the present invention will be described in more detail with reference to Examples, but it will be understood that the present invention is not limited to these Examples and can be further modified in various ways.

Example 1 A Watts bath (solvent: water) having the following composition was prepared.

Nickel sulfate 280 g/l Nickel chloride 50 g/l Boric acid 409/1 To this acidic Ni plating bath, 80 ppm of polyvinylpyrrolidone (molecular weight approximately 40,000) and 500 ppm of saccharin soda (basic brightener) were respectively added. .

Then, using this plating bath, a current density of 0, 5 to 10
When plating was carried out on a mirror-polished brass plate for about 10 minutes at A/dm2 and a temperature in the range of 40 to 70°C, a plated film was obtained which was very fine and had a satin appearance, with the appearance of a face etc. vaguely visible.

The depth of the rough surface of this coating was about 0.5 μm.

Note that after maintaining the above plating bath at 55°C for one week,
When plating was performed again in the same manner as described above, the rough surface depth and appearance of the resulting plating film were almost the same as the original one.

After leaving the bath for two weeks, it is filtered using a regular cartridge type filter to remove aggregates, and then the above-mentioned polyvinylpyrrolidone is added to obtain a plating film that has the same satin appearance as when the bath was prepared. I was able to do it.

Comparative Example In Example 1 above, 1) ton of polyvinyl pyro was added to 20.
If 000ppm (20g/l) is added, a resin-like plating film will result, and the amount added will be reduced to 0.8p.
No satin effect was observed when it was expressed as pm.

Also, instead of polyvinylpyrrolidone, N-methylbiDI
When 1100pp of J ton (molecular weight 97) was added,
No satin effect was observed.

Example 2 200 ppm of polyvinylpyrrolidone (molecular weight 360,000) and 500 ppm of polyvinylpyrrolidone (molecular weight 360,000) were added to the Watts bath used in Example 1.
ppm of saccharin soda and plated under the same conditions as in Example 1, the rough surface depth was 0.5 μm.
A plated film with a uniform satin appearance was obtained.

Example 3 1100 pp of polyvinylpyrrolidone (molecular weight 10,000) and 500 pp of polyvinylpyrrolidone (molecular weight 10,000) were added to the Watts bath used in Example 1.
Example 1 by adding pm of saccharin soda and saccharin soda, respectively.
When plating was carried out under the same conditions as above, a plated film with a uniform satin appearance and a rough surface depth of approximately 0.5 μm was obtained.

Example 4 A sulfamic acid bath (solvent: water) having the following composition was prepared.

Nickel sulfamate 410 g/l Nickel chloride 30 g/l Boric acid 40 g/l To this acidic electrolytic Ni plating bath, 1,200 ppm polyvinylpyrrolidone (molecular weight 40,000) and 5c
c/7 Nishilite #63 (trade name manufactured by Nishilite Co., Ltd., which is a basic brightener) was added.

When plating was carried out in this bath at a current density of 2 to 15 A/dm2, a very rough and glossy satin appearance was obtained.

Example 5 Into the Watts bath used in Example 1, 1,000 ppm of Desmorphene 600 (trade name of Bayer AG, a polyester obtained by polymerizing phthalic acid with diols and triols) and 500 ppm of saccharin were added. and soda were respectively added.

When plating was performed using this plating bath under the same conditions as in Example 1, a uniform plated film with a rough surface depth of about 0.3 μm and a satin appearance was obtained.

Examples 6 to 8 As a polyester, 1,000 ppm of Desmorphene 5OO (trade name manufactured by Bayer AG, obtained by polymerization of adipic acid and phthalic acid with a triol) was used in Example 6, and 1. OOppm of Desmorphen 1100 (same composition as the above Desmorphen 800) was used in Example 7, and 1.000 ppm of Desmorphen 1700 (trade name manufactured by Bayer AG, obtained by polymerization of adipic acid and glycol) was used. The procedure was the same as in Example 5 except that these were used in Example 8.

In these Examples as well, a uniform satin appearance with a roughness depth of approximately 0.3 μm was obtained.

Example 9 Into the Watts bath used in Example 1 above, 1100 ppm of polythiol ester (obtained by polymerization of adipic acid and dithioethylene glycol) and 500 ppm of polythiol ester were added.
and saccharin soda were added respectively.

When plating was performed using this plating bath under the same conditions as in Example 1, a plated film having a uniform satin appearance was obtained.

Claims (1)

[Claims] 1 Polyvinylpyrrolidone, a water or alcohol soluble polymer with a molecular weight of 10,000 or more, molecular weight 5
00 to 5,000 polyester and molecular weight 500 to
At least one polymer selected from the group consisting of 5,000 polythiol esters 1/l to 109/1. and 0.19/11 to 30 g/l of a basic brightener, respectively.