JPH09169509A - Production of carbon black molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain a carbon black molding excellent in compacting property and dispersibility by repeating the packing and pressing work of a carbon black plural times. SOLUTION: The carbon black 2 having 0.1-0.2g/cm<3> bulk density is packed into a metallic mold surrounded with a piston 1, a die 3 and lower punch 4, pressed with a piston 1 and further pressed with the lower punch 4 by moving the die 3 downward so that the total pressurizing force becomes 1-250kgf/cm<2> and the carbon black molding having 0.4-1.2g/cm<3> bulk density is obtained by repeating the pressing work 2-10 times.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a carbon black pressure-molded body. The bulk density of carbon black is extremely low at 0.1 to 0.2 g / cc. Because of this,
The problems of packaging bags, transportation costs and storage costs of warehouses, and environmental pollution due to dusting during handling are becoming problems. In order to solve these problems, the present inventors have developed a carbon black pressure molded body. For example, as described in Japanese Patent Application No. 7-24430, the carbon black molded body developed by the present inventors has solved the above problems,
In addition, it has excellent dispersibility in a vehicle when used as a coloring component of ink or the like.

According to the present invention, when producing such a carbon black pressure-molded article, the height of the molding die is lowered by carrying out a stepwise filling operation and a pressure molding operation, Achieving downsizing of manufacturing equipment and reduction of manufacturing cost of equipment. Carbon black generally has a very low bulk density of about 0.1 g / cc immediately after production. Due to this low bulk density, there are problems such as high packaging bag costs and storage costs in warehouses, high transportation costs by trucks, freight cars, ships, etc. There is.

In order to solve such a problem, a dry granulation product or a wet granulation product called a bead product is usually used. The beaded product has a bulk density of 0.3 to 0.5 g / cc, which is considerably higher than that of untreated carbon black.
However, the effect of suppressing dust generation during weighing and the effect of suppressing pulverization of granulated products during transportation cannot be said to be sufficient. In addition, the dispersibility in varnish or resin, which is a raw material of paint or ink, is deteriorated due to granulation, and beads may not be used in some cases.

Japanese Patent Application Laid-Open No. 6-122111 attempts to obtain a molded body by charging carbon black powder in a closed mold container, reducing the pressure in the container, and then restoring the pressure in the container to normal pressure. I have. However, the molding pressure applied by the reduced pressure is lower than the atmospheric pressure (about 1.03 kg / cm ² ), and the bulk density cannot be increased as the transportation cost and the warehouse cost are reduced.

On the other hand, as an attempt to solve the above problems by pressure-molding carbon black, for example, British Patent 551862 discloses carbon black,
Press degassing of lamp black and the like and German Patent 1302382 describe a device for densifying by pressing. However, the distribution form of carbon black which is industrially used is an ungranulated product, or a granulated product by dry granulation, wet granulation or oil-added granulation, and the pressure-molded product is still accepted in the market. Has not been done.

The present inventors have examined the problems of these conventionally existing pressure-molded products and developed a new and practical carbon black molded product (Japanese Patent Application No. 7-2443).
0).

[0007]

What has been clarified by the inventors' earnest study here is that, for example, in order to achieve a good balance of compactness and dispersibility of carbon black, the molding pressure of carbon black must be adjusted. 1 kgf / c
That is, it is necessary to perform pressure molding to m ² or more and less than 250 kgf / cm ² . Therefore, the pressure treatment reduces the apparent volume of carbon black from 1/2 to 1/6.

Therefore, in order to manufacture a molded body having a thickness which is industrially easy to use, it is necessary to use a mold for molding which is extremely long in the vertical direction. For example, in order to manufacture a molded body having a thickness of 25 cm, the height is 1.
A molding die that reaches 5 m is required. In addition to this, a piston section and a hydraulic unit are further required in the vertical direction, and the device as a whole extends over 4 m or more. Furthermore, it is extremely difficult to manufacture such a molding die that is extremely long in the vertical direction with high accuracy and to vertically drive the molding die accurately by 1 m or more.

[0009]

Therefore, the inventors of the present invention have conducted further diligent research to solve the above problems and obtain a method for producing a carbon black pressure-molded article which can be industrially carried out, and added a specific method. The inventors have found that the above problems can be solved by a pressure operation, and have reached the present invention. That is, the present invention resides in a method for manufacturing a carbon black molded body, in which, when manufacturing one carbon black molded body, the raw material filling and pressurizing operations are performed a plurality of times.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The carbon black used as a raw material in the present invention may be any fine carbon powder such as carbon black produced by a furnace method, lamp black and acetylene black. Further, the produced carbon black may be post-treated with various oxidizing agents or granulated.

The mold used for the pressure molding may be a mold of any material as long as it has a strength capable of withstanding the applied pressure at the time of molding. For example, a metal mold is SU.
Stainless steel molds such as S304 and SUS316, and super steel such as tungsten carbide can be used. Further, as the resin mold, a fluororesin such as polytetrafluoroethylene (PTFE), polytrifluorochloroethylene (PCTEF), polytetrafluoroethylene / hexafluoropropylene (FEP) (trademark: “Teflon”) ) Molds, plastics such as nylon, polycarbonate and polyimide, FRP such as CFRP and GFRP as a composite material, and alumina, zirconia, mullite and the like as a ceramic mold can be used.

The molding method is carried out by filling the mold with the raw material carbon black and pressurizing the mold. The molding temperature may be room temperature. For example, a mold of the apparatus shown in FIG. 1 is filled with carbon black powder and pressurized by a piston (1).
At this time, if the die (3) is moved downward at the same time, the carbon black is also pressed by the lower punch (4) and is pressed from both upper and lower directions, which is more efficient. In FIG. 1, 2 is carbon black.

The degree of pressurization is 1 to 250 kgf / cm ² ,
When the amount is preferably ² to 150 Kgf / cm ² , a carbon black molded body having a density suitable for reduction of transportation cost, storage cost and the like, having sufficient strength for handling, and also maintaining dispersibility in a vehicle is obtained. be able to. The density of the molded body is preferably 0.4 to 1.2 g / cc.

The present invention is characterized in that the filling of the carbon black into the mold and the pressurizing operation are carried out a plurality of times.
That is, after the above pressing, carbon black powder is further filled in the mold. It may be deposited on carbon black that has already been pressed. Then, the newly filled carbon black is pressurized and becomes integrated with the carbon black which has already been pressurized. This operation is repeated several times. Although the number of repetitions is not limited, it is practically about 2 to 10 times, preferably about 2 to 5 times. It may be appropriately selected depending on the usable work space and the size of the mold.

By carrying out such a repetitive operation, it becomes possible to manufacture a carbon black molding of a practical size using a mold of a practical size. In addition, the pressure at the time of final pressurization is set to 1.
If it is more than twice, the molded body can be obtained as a continuous body in which the seams between the layers formed by each pressurization do not substantially exist, and also from the viewpoint of the breakage resistance when handling the molded body. Is particularly convenient.

[0016]

EXAMPLES Next, the present invention will be described in more detail by way of examples. (Example 1) Carbon black powder "# 45" manufactured by Mitsubishi Chemical Corporation was used to perform pressure molding by the following operation. A conceptual diagram of the operation is shown in FIG.

The mold has a size of 30 cm × 30 cm and a height of 1.5.
The size of m was used. First, the mold is filled with carbon black powder up to a height of 50 cm, and 80 kgf /
A pressure of cm ² was applied to obtain a molded body having a height of 14.9 cm.
Furthermore, a carbon black powder with a height of 35.1 cm is added and pressure is applied at 80 kgf / cm ² to obtain a height of 25.3 cm.
A molded body of was obtained.

Further, carbon black powder is added to a height of 24.
An additional 7 cm was added and pressure was applied at 100 kgf / cm2 to obtain a molded product having a height of 31.5 cm. (Example 2) Using the carbon black powder and the mold used in Example 1, pressure molding was performed by the following procedure.

First, the carbon black powder was placed on the mold at a height of 1.
filled up to m, 80kgf / cm^TwoPress at 29.
A molded body having a height of 0 cm was obtained. Furthermore, carbon black
71.0cm height added powder, 80kgf / cm^TwoAdd
It was pressed to obtain a molded body having a height of 50.0 cm. Furthermore, the car
Bonk powder is added to the height of 50.0 cm for 100k.
gf / cm ^TwoAnd pressurize to obtain a molded product with a height of 64.0 cm.
Was. (Example 3) Carbon black powder used in Example 1 and
Pressure molding was performed by the following operation using a mold.

First, a mold was filled with carbon black powder having a height of 1 m and pressurized at 95 kgf / cm ² , and the height was 2
A molded product of 8.2 cm was obtained. Further, 71.8 cm of carbon black powder was added and pressed at 95 kgf / cm ² to obtain a molded product of 47.9 cm. Furthermore, 52.1 cm of carbon black powder is added to 100 kgf / cm ²
Then, pressure was applied to obtain a 62.2 cm molded body. In the molded body,
Layered seams were seen for each pressurization operation. (Comparative Example 1) Using the carbon black powder and the mold used in Example 1, pressure molding was performed by the following procedure.

The mold was filled with carbon black powder up to a height of 1 m and pressed at 100 kgf / cm ² . The obtained molded body had a height of 29 cm.

[0022]

EFFECTS OF THE INVENTION According to the present invention, a carbon black molded article having excellent compactness and dispersibility can be efficiently obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a pressurizing device that can be used for implementing the present invention.

FIG. 2 is a conceptual diagram of operations performed in Example 1.

Claims (3)

[Claims] 1. A method for producing a carbon black molded body, wherein when manufacturing one carbon black molded body, the raw material filling and pressurizing operations are performed a plurality of times. 2. The carbon black according to claim 1, wherein the pressure of the final pressurizing operation among the pressurizing operations is 1.2 times or more of the maximum pressure among the pressures of the previous pressurizing operations. Molded body manufacturing method. 3. The pressure of the final pressurizing operation is 1 kgf / cm.
^The method for producing a carbon black molded body according to claim 1 or 2, wherein the carbon black molded body is ² or more and less than 250 kgf / cm ² .