JP3062630B2 - Electroless composite plating solution, electroless composite plating method and electroless composite plating film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electroless composite plating solution,
The present invention relates to an electroless composite plating method and an electroless composite plating film.

[0002]

2. Description of the Related Art Fluorinated graphite and polytetrafluoroethylene (PTFE) have characteristics such as self-lubrication, low friction, water repellency, oil repellency, and non-adhesiveness. Dispersed in an aqueous solution of salt, electrodeposited graphite fluoride etc. together with the metal on the substrate by electroplating, and has both the unique properties of non-metallic graphite fluoride and the properties of the matrix metal There is known a composite plating method by an electroplating method for forming a composite film.

In such a plating method, in order to disperse and precipitate graphite fluoride in an aqueous solution of a metal salt, it is necessary to positively charge the graphite fluoride particles and to create a completely wet state. However, fluorinated graphite has extremely strong water repellency, and it is necessary to add a large amount of a surfactant in order to obtain a stable dispersion state.
In addition, since the surface of the fluorinated graphite in the fluorinated graphite eutectoid plating film thus obtained is covered with a surfactant, the water repellency is extremely poor immediately after plating. It is necessary to dry the plating surface.

[0004] A method is also known in which insoluble inorganic salts are dispersed in an electroless plating solution, and these fine powders are co-deposited on a substrate (J. Grayman, Galvan).
o, 39 , 589 (1970)). However, fluorinated polymer graphite is a highly hydrophobic substance, so it is very difficult to disperse it in an electroless plating solution using a normal surfactant, even if it was temporarily dispersed. However, the stability of the liquid is extremely poor, and the liquid cannot be used for a long time. In addition, since the amount of the surfactant added is large, it is necessary to perform heat treatment after plating to dry the plating surface, as in the case of electrolytic plating.

[0005]

Means for Solving the Problems The present inventor has made intensive studies in view of the prior art as described above. As a result, when a pitch fluoride that has not been conventionally used is used as the substance to be dispersed, the pitch fluoride can be stably dispersed in the electroless plating solution with a very small amount of a surfactant. It has been found that by using the electroless composite plating solution thus obtained, a good electroless composite plating film in which a pitch fluoride is codeposited can be formed. The formed electroless composite plating film has excellent water repellency as compared with the plating film obtained by codepositing graphite fluoride or PTFE, and shows high water repellency without heating and drying immediately after plating. I found out.

That is, the present invention provides the following electroless composite plating solution, electroless composite plating method, and electroless composite plating film.

[0007] i) An electroless composite plating solution characterized in that pitch fluoride is dispersed in an electroless plating solution by using a cationic surfactant in the plating solution.

Ii) Using an electroless composite plating solution in which pitch fluoride is dispersed in an electroless plating solution using a surfactant showing cationicity in the plating solution, An electroless composite plating method comprising forming a composite plating film in which pitch fluoride is eutectoid.

Iii) An electroless composite plating film characterized by co-depositing pitch fluoride in a metal plating film by an electroless plating method.

The pitch fluoride used in the present invention is represented by composition formula C
A compound having a composition represented by Fx (0.5 <x <1.8), in which one to three fluorine atoms are firmly bonded to each carbon atom by a covalent bond. The color is brown to yellowish white to white, is a compound which is very stable in air and has excellent water resistance and chemical resistance, and has a layered structure. Industrially, it is obtained by directly reacting the pitch with fluorine gas at around normal temperature. In the present invention, the particle size of the pitch fluoride to be added is not particularly limited, but if it is larger than the thickness of the plating film, the pitch fluoride drops due to friction of the plating surface, so that fine-particle pitch fluoride is used. It is usually preferable that the thickness is about 10 μm or less,
It is more preferably at most μm. The amount of the fluorinated pitch added to the plating solution is not particularly limited and may be determined depending on the stirring state of the plating solution, the desired amount of eutectoid, etc., and is generally about 500 g / l or less, preferably 1 to 50 g / l. It may be about l.

In the present invention, the type of plating solution to which pitch fluoride is to be added is not particularly limited, and various known electroless plating solutions can be used. Examples of such an electroless plating solution include an electroless copper plating solution, an electroless nickel plating solution, and an electroless cobalt plating solution. As these plating solutions, those having various compositions are known, and in the present invention, any of these known electroless plating solutions can be used.

In the plating solution of the present invention, a surfactant is used to uniformly disperse the pitch fluoride in the plating solution. As the surfactant, it is necessary to use a surfactant molecule that exhibits cationicity at the pH of the plating solution. For example, a water-soluble cationic or nonionic surfactant or a cationic surfactant at the pH of the plating solution is required. An amphoteric surfactant exhibiting properties can be used. In this case, a quaternary ammonium salt, a secondary,
Non-ionic surfactants include polyoxyethylene, polyethyleneimine and ester-based surfactants, and amphoteric surfactants include carboxylic acid-based and sulfone-based surfactants. And the like. In particular, it is preferable to use a fluorinated surfactant having a CF bond in the molecule. CF in the molecule
A nonionic surfactant having a bond shows cationicity only in the case of an acidic plating solution.

The amount of the surfactant to be added to the plating solution is preferably about 1 mg to 100 mg per 1 g of pitch fluoride, more preferably about 1 mg to 30 mg per 1 g of pitch fluoride. In the present invention, by using the pitch fluoride, it is possible to uniformly disperse the surfactant in the plating solution even when the amount of the surfactant used is very small. As a result, the amount of the surfactant adhered to the fluorinated pitch is small, and high water repellency is exhibited immediately after plating.

In the plating solution of the present invention, it is preferable to perform plating while stirring the plating solution in order to uniformly disperse the pitch fluoride. The stirring method is not particularly limited, and ordinary mechanical stirring means, for example, a method of screw stirring, a method of stirring with a magnetic stirrer, and the like can be adopted.

With the plating solution of the present invention, a plating film can be formed on various materials, for example, a composite plating film can be formed on various metal materials, plastic materials and the like. By using the composite plating solution of the present invention, a composite plating film obtained by codepositing a pitch fluoride having excellent lubricity, abrasion resistance, water repellency, etc. on the inside of a cylinder, a sliding member such as a piston pin, and the like is uniform. It can be easily formed with a small thickness.

The plating conditions may be appropriately determined according to the type of plating solution to be used. In general, the plating temperature and pH may be the same as those in the case of ordinary plating. After performing the pretreatment described above, an electroless plating treatment may be performed.

In the plating film formed using the plating solution of the present invention, the amount of the pitch fluoride contained in the plating film may be appropriately determined according to the purpose of use. The amount of pitch fluoride contained in the film can be changed by adjusting the amount, adjusting the plating conditions, and the like. Generally, the greater the amount of pitch fluoride contained in the plating film, the lower the adhesion between the plating metal and the base material. Therefore, the amount of pitch fluoride in the plating film is 8% by volume.
It is appropriate to set it to about 0% or less, and especially when the mechanical strength of the plating film is required, it is necessary to avoid eutecting a large amount of pitch fluoride. Preferably, the volume fraction is about 10% or less. The lower limit of the eutectoid content of pitch fluoride is not particularly limited and may be appropriately set according to the purpose of use. % Or more is preferable.

[0018]

According to the electroless composite plating solution of the present invention,
A good composite plating film can be formed on various materials, and the formed plating film is made of conventional fluorinated graphite, P
It has higher water repellency than a plating film in which TFE or the like is eutectoid, and also has excellent lubricity, abrasion resistance, water repellency and the like. Further, since the dispersibility of the fluorinated pitch in the plating solution is very good, the amount of the surfactant added can be significantly reduced, and good water repellency is exhibited immediately after plating.

[0019]

The present invention will be described in more detail with reference to the following examples.

[0020]

Example 1 Softening point: 100 ° C., quinoline insoluble content: 0.2 w
A double amount of hydrogenated anthracene oil was added to a coal tar pitch containing 30% by weight of benzene insoluble matter and 30% by weight of benzene.
The mixture was heated for 0 minutes, and the reduced pitch was obtained by removing the hydrogenated anthracene oil at 300 ° C. under reduced pressure.

Next, a low-molecular-weight component is removed from the reduced pitch by introducing nitrogen gas, and thermally polymerized at 400 ° C. for 5 hours to obtain a softening point of 300 ° C., a quinoline-insoluble content of 60 wt%,
Benzene insoluble content 98 wt%, mesophase content 90%
The above mesophase pitch was obtained.

After 50 g of the obtained pitch was charged into a nickel reactor, the system was evacuated and filled with argon gas. Then, at 70 ° C., a fluorine gas (mixed gas of 20 vol% fluorine and 80 vol% argon) was supplied at an average flow rate of 6%.
After flowing at a flow rate of 50 cc / min and reacting for 20 hours, 144 g of pitch fluoride was obtained. Upon elemental analysis, the composition formula was CF _1.39 .

The thus obtained pitch fluoride was added in an amount of 1% by weight to an electroless nickel plating bath having the following composition. At this time, a tertiary perfluoroammonium salt (C ₈ F ₁₇ SO ₂ NH (CH ₂ ) ₃ N) is used as the surfactant.
⁺ (CH ₃ ) ₃ Cl ⁻ ) to 1 g of pitch fluoride
It was added to 4.5 mg.

Electroless nickel plating bath composition Nickel sulfate 20 g / l Sodium citrate 8 g / l Sodium malonate 20 g / l Sodium hypophosphite 20 g / l Using the above electroless nickel plating bath, the bath temperature was stirred. An iron test piece (30 mm × 50 mm, thickness 0.5 mm) was plated at 80 ° C. for about 1 hour to form a 10 μm fluorinated pitch eutectoid plating film. The contact angle of water was measured on the obtained plating film immediately after plating and after vacuum drying, and the water repellency was examined. The results are shown in Table 1.

[0025]

Comparative Example 1 Electroless nickel plating was performed in the same manner as in Example 1 except that pitch fluoride was not added. The results of measuring the contact angle of water on the obtained nickel plating film are shown in Table 1 below.

[0026]

Comparative Example 2 The procedure of Example 1 was repeated, except that graphite fluoride was used instead of pitch fluoride, and that the tertiary perfluoroammonium salt was added so as to be 40 mg per 1 g of graphite fluoride. Plating was performed under the same conditions as in Example 1, and the water repellency of the plating film was measured. The results are shown in Table 1 below.

[0027]

Comparative Example 3 PTFE was used instead of fluorinated graphite.
1g of PTFE
The plating was performed in the same manner as in Comparative Example 2 except that the amount was changed to 40 mg, and the water repellency of the plating film was measured.
The results are shown in Table 1 below.

Table 1 Immediately after plating (degree) After vacuum drying (degree) Example 1 119.3 123.2 Comparative Example 1 51.3 56.2 Comparative Example 2 46.7 102.0 Comparative Example 3 67.5 110.0

[0029]

Example 2 1% by weight of the pitch fluoride obtained in Example 1 was added to an electroless copper plating bath having the following composition. At that time, a tertiary perfluoroammonium salt (C ₈ F ₁₇ SO ₂ NH (CH ₂ ) ₃ N ⁺ (C
H ₃ ) ₃ Cl ⁻ ) was added to 4.5 g of pitch pitch to 4.5 g.
mg.

Electroless copper plating bath composition Copper sulfate 30 g / l Sodium carbonate 25 g / l Rochelle salt 140 g / l Sodium hydroxide 40 g / l Formalin (37%) 166 mg / l Using the above electroless copper plating bath, stirring was carried out. At a bath temperature of 20 ° C., an iron test piece (30 mm × 50 mm, thickness 0.5 m)
m) was plated for about 40 minutes to form a 15 μm-pitch eutectoid fluoride plating film. The contact angle of water was measured on the obtained plating film immediately after plating and after vacuum drying, and the water repellency was examined. The results are shown in Table 2.

[0031]

Comparative Example 4 Electroless copper plating was performed in the same manner as in Example 2 except that pitch fluoride was not added. The results of measuring the contact angle of water on the obtained plating film are shown in Table 2 below.

[0032]

Comparative Example 5 Example 2 was repeated except that fluorinated graphite was used instead of pitch fluoride, and that a tertiary perfluoroammonium salt was added in an amount of 40 mg per 1 g of the fluorinated graphite. Plating was performed under the same conditions as in Example 2, and the water repellency of the plating film was measured. The results are shown in Table 2 below.

[0033]

[Comparative Example 6] PTFE was used instead of fluorinated graphite.
1g of PTFE
The plating was performed in the same manner as in Comparative Example 5 except that the amount was 40 mg, and the water repellency of the plating film was measured.
The results are shown in Table 2 below.

Table 2 Immediately after plating (degree) After vacuum drying (degree) Example 2 117.2 121.5 Comparative Example 7 55.6 60.1 Comparative Example 8 44.5 103.4 Comparative Example 9 67.3 109.6 From the above results, it can be seen that the composite plating solution of the present invention can form a plating film having excellent water repellency even immediately after plating.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C23C 18/00-18/54

Claims (3)

(57) [Claims] 1. An electroless composite plating solution comprising a surfactant having a cationic property in the plating solution and pitch fluoride. 2. An electroless plating solution containing a surfactant having a cationic property and a pitch fluoride in a plating solution,
An electroless composite plating method characterized by forming a composite plating film in which pitch fluoride is codeposited on a substrate by an electroless plating method. 3. An electroless composite plating film obtained by co-depositing pitch fluoride in a metal plating film by an electroless plating method.