JP2824596B2 - Manufacturing method of conductive fine coke - Google Patents

Description

The present invention relates to a method for producing conductive fine coke by electroless plating.

ADVANTAGE OF THE INVENTION According to this invention, conductive fine-powder coke with low electric resistivity can be manufactured efficiently at low cost.

The conductive fine coke produced by the present invention is useful as a conductive filler for an electromagnetic wave shielding plate, a conductive filler for an antistatic agent, and the like.

[Conventional technology]

2. Description of the Related Art Conventionally, in performing electroless plating, a pretreatment such as application of a catalyst is performed on an object to be plated.

That is, prior to performing the electroless plating, the object to be plated is subjected to a catalyst treatment using a hydrochloric acid aqueous solution of stannous chloride and an aqueous solution of palladium chloride or a palladium tin colloid, and a pretreatment for activation thereof, and Prior to this pretreatment step, a step of degreasing and cleaning the surface to be plated or adjusting the surface may be employed.

When the object to be plated is a powder or a fiber, the above-described steps of degreasing and cleaning, surface conditioning, application of a catalyst, and activation thereof are usually employed.

[Problems to be Solved by the Invention] The above-described catalyst is used in the case of producing electroconductive fine coke having a low electric resistivity by performing electroless plating using fine coke as an object to be plated and metalizing the particle surface. If pretreatment such as application is performed, there is a problem that the production cost is extremely high because of many steps.

The present invention provides a new technical means capable of directly performing electroless plating without performing pretreatment such as the application of a catalyst in performing electroless plating using fine coke as a material to be plated. Therefore, it is a technical object to reduce the manufacturing cost.

[Means for solving the problem]

The technical problem can be solved by the present invention as described below.

In other words, the present invention provides a method for producing fine coke that has not been subjected to a pretreatment such as catalyst application, by using an electroless plating solution to which a surfactant has been added, and by directly performing electroless plating. This is a method for producing conductive fine coke comprising metallizing the surface of each particle.

 Next, the configuration of the present invention will be described in detail.

First, the fine powder coke to be plated in the present invention, using a well-known pulverizer such as a ball mill, a vibration mill, a jet mill, and the like, an ordinary coke, according to a conventional method, an average particle diameter of 100 μm or less, preferably 5 to 5 μm. It is finely pulverized to about 50 μm.

It should be noted that coke preferably has as little volatile and sulfur content as possible to corrode the metal.

Next, the electroless plating solution used in the present invention is obtained by adding a surfactant described later to a commercially available electroless plating solution.

The type of metal to be plated can be arbitrarily selected, but Ni, Cu
Etc. are preferred.

The surfactant used in the present invention can be selected from commercially available products, but anionic surfactants and amphoteric surfactants are suitable, and sulfonic acid-based surfactants (eg, alkylbenzene sulfonate, alkyl sulfosuccinate, etc.) are particularly suitable. And betaines (eg, alkyltaurine, laurylbetaine, etc.) are preferred.

The amount added to the electroless plating solution may be a small amount, from 0.01 to
What is necessary is just to select from the range of 5 wt%. The addition of 0.01 wt% or less makes it difficult to obtain the desired effect of lowering the electric resistivity of the object to be plated. As the amount increases, the electric resistivity decreases until about 5 wt% is added. If it exceeds%, it will peak off. Particularly preferred addition amount is 0.03 to 3 wt%
It is.

The electroless plating treatment may be performed according to a conventional method, and the treatment temperature may be selected from a range from room temperature to 100 ° C., and the treatment time may be selected from a range from 10 minutes to 60 minutes. In addition, when the processing time is 10 minutes or less, the electrical resistivity does not decrease because the plating film is being generated, and as the time increases, the electrical resistivity decreases until about 60 minutes, but when the time exceeds 60 minutes, It reaches a plateau. Particularly preferred treatment times are between 20 and 60 minutes.

The object to be plated can be obtained by filtering and air-drying the object to be plated after the electroless plating according to a conventional method.

[Action]

In the present invention, the fine coke to be plated is directly subjected to a pretreatment such as the above-described catalyst application without being subjected to the pretreatment.
If the electroless plating is performed, a metal coating is formed on the surface of each particle of the fine coke, and as shown in Examples and Comparative Examples described later, catalyst application using a stannous chloride aqueous solution of hydrochloric acid and an aqueous solution of palladium chloride and its activity are performed. A conductive fine coke having an electric resistance value equal to or lower than that in the case of performing the pretreatment for chemical conversion can be obtained because an electroless plating solution to which a surfactant is added is used.

The present inventors have conducted extensive and numerous experiments on electroless plating of fine powdered coke for many years while repeating trial and error in order to achieve the above technical problem. Just by adding an activator, even without performing the pretreatment such as the above-mentioned catalyst application, we obtained data that doubted the unexpected result that results equivalent to or better than those obtained by applying were obtained. In order to confirm the nature, we repeated the test and worked on the theoretical elucidation. The reproducibility was confirmed as shown in the examples below, but unfortunately the theoretical elucidation has not been performed yet.

Incidentally, the present inventor, from the data obtained by repeating the additional test, when viewed microscopically, if the metal coating is uniformly formed on the surface of each particle of fine coke, the electrical resistivity is low, It has been confirmed that it does not decrease very much in the case of non-uniformity, or conversely increases.

[Examples] In order to explain the contents of the present invention in more detail, several representative examples are extracted from many data accumulated by the present inventors and shown as examples. The present invention is not limited to the examples, and it is obvious that the embodiments can be modified and carried out without departing from the spirit and the spirit of the present invention.

Example 1 In a beaker, 140 ml of solution A and 140 ml of solution B of TMP New Chemical Nickel (trade name: nickel electroless plating solution: manufactured by Okuno Pharmaceutical Co., Ltd.) were added to make 1 with tap water.
0.2 wt% of OT (trade name: anionic surfactant: alkyl sulfosuccinate: manufactured by Wako Pure Chemical Industries) was added to prepare an electroless plating solution.

In the above plating solution, the average particle diameter is 8.81 μm, and the specific surface area is 0.
Electrical resistivity (JIS K1469) of 4.5 × 10 ^-1 Ωcm at 76m ² / g
1 g of the fine coke was charged without any pretreatment such as catalyst application, and subjected to electroless plating at 80 ° C. for 60 minutes. After plating, fine coke is filtered out of the solution, washed with water,
After washing with methanol and acetone, the powder was naturally dried to obtain 2.81 g of conductive fine coke having a nickel film formed on the surface of each particle. The electrical resistivity (JIS K1469) of the conductive fine coke obtained here is 7.5 × 10 ^-3 Ω · c
m.

Examples 2 to 9 Same as Example 1 except that the type and amount of surfactant, the particle size and input amount of fine coke, and the temperature and time of electroless plating were changed as shown in Table 1. Thus, conductive fine powder coke having a nickel film formed on the surface of each particle was obtained. Electrical resistivity of each conductive fine powder obtained (JIS K1469)
Was as shown in the table.

The electrical resistivity (JIS K1469) of each fine coke before the electroless plating was 4.5 × 10 ⁻¹ Ω · cm.

In addition, from each electric low efficiency shown in the above table, it is understood that anionic and zwitterionic surfactants are more effective as nonionic and cationic surfactants.

Comparative Example A solution 1 of TMP New Chemical Nickel (described above) in a beaker
An electroless plating solution was prepared by adding 40 ml and 140 ml of the solution B, and adjusting the value to 1 with tap water.

On the other hand, 1 g of the fine coke powder used in Example 1 was immersed in 100 ml of a 10% aqueous solution of Desquel X-100 (trade name: cationic surfactant: manufactured by Okuno Pharmaceutical Industries) for 5 minutes, washed by filtration, and then washed with water. Sensitizer (trade name: Stannous chloride containing:
After immersion in 500 ml of a 10% aqueous solution of Okuno Pharmaceutical Co., Ltd. for 2 minutes, the filter was washed with water, and further immersed in 500 ml of a 5% aqueous solution of an activator (trade name: palladium chloride: manufactured by Okuno Pharmaceutical) for 2 minutes, and then washed by filtration. did.

Into the plating solution, 1 g of fine coke that had been subjected to the pretreatment such as the above-mentioned catalyst application was added and subjected to electroless plating at 45 ° C. for 60 minutes. After completion of the plating treatment, fine coke was filtered out of the solution, washed with water, washed with methanol and acetone, and dried naturally to obtain 3.01 g of conductive fine coke having a nickel coating formed on each particle surface. Was. The electrical resistivity (JIS K1469) of the conductive fine powder coke obtained here is
It was 2.8 × 10 ⁻³ Ω · cm.

By comparing the value of the electric resistivity obtained in each of the above Examples, in particular, the value of the electric resistivity obtained in Example 5 with the value of the electric resistivity obtained in the above Comparative Example, it is possible to obtain a catalyst application. It can be understood that even if the electroless plating is performed directly without performing the pretreatment described above, the same electrical resistivity as that obtained by performing the pretreatment can be obtained.

〔effect〕

Coke is easy to pulverize, the shape of the finely divided particles is close to spherical, and by a simple operation such as sieving, a shape and particle size that are surprisingly uniform are obtained,
In addition, the price is inexpensive as compared with, for example, graphite, but the present invention directly applies such fine coke as an object to be plated without performing the above-described pretreatment such as catalyst application.
Electroless plating is performed to obtain conductive fine coke having a low electric resistivity of the order of 10 ^-2 to 10 ^-3 Ω · cm.

According to the present invention, the work efficiency is good and the manufacturing cost is reduced because the pretreatment such as the application of the catalyst can be omitted.

Therefore, it can be said that the present invention has a remarkable effect of expanding the uses of coke and providing a conductive filler useful for various uses at low cost.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C23C 18/31

Claims (2)

(57) [Claims] An electroless plating method in which a surfactant is added to fine coke that has not been subjected to a pretreatment such as catalyst application, and then directly subjected to electroless plating to obtain the surface of each particle of the fine coke. A method for producing electrically conductive fine coke, comprising metallizing coke. 2. The method according to claim 1, wherein the surfactant is a sulfonic acid-based surfactant.