JPH10265702A - Carbon black aggregate and heat insulating material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a carbon black aggregate having low dusting properties when constructing or dismantling a furnace by aggregating many carbon black grains, forming an integral shape and then maintaining a specific aggregate state. SOLUTION: This carbon black aggregate is obtained by aggregating many powdery carbon black grains which are raw materials, regulating the density of the resultant aggregate to preferably 1.2-6 times based on the bulk density of the carbon black powder, placing the regulated aggregate in, e.g. a mold and pressing the aggregate with a piston, etc. The prepared carbon black aggregate has <=0.100 kcal/m.hr. deg.C heat conductivity. The carbon black used is preferably the one, produced by a furnace process and having <=80 nm grain diameter and >=40 and <=150 (mL/100 g carbon black) volume of DBP oil absorption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing a material having a low thermal conductivity,
TECHNICAL FIELD The present invention relates to a carbon black aggregate having low dust generation during furnace construction and furnace disassembly, and a heat insulating material using the aggregate.

[0002]

2. Description of the Related Art An industrial furnace is used for melting, refining, various processes, hot working, sintering, firing, reaction heating, or industrial waste in the metal industry, general machine industry, electric / electronic industry, ceramic industry, chemical industry, and the like. It is used for incineration and other processes. When these furnaces are used, the heat-generating part is usually covered with a heat insulating material from the viewpoint of improving energy efficiency, securing a firing temperature, and securing safety. The selection of the heat insulating material is appropriately selected from the temperature, the thermal conductivity, the physical / chemical strength, the service life, the price, the adaptability at the time of the operation, the nonflammability, and the like. In an industrial furnace, refractory bricks, ceramic fibers, and the like are used. However, in a case where mixing of impurities is rejected or in a high-temperature furnace exceeding 1500 ° C., a carbon-based heat insulating material is mainly used. As a carbon-based heat insulating material, graphite powder or graphite particles, carbon black powder or particles, carbon fiber felt, carbon foam, and the like have been proposed, but none of them sufficiently satisfy dust generation, cost, and performance. .

[0003]

These problems have been studied so far. For example, Tokuho 5
-19509 and industrial heating 26 (5), 51 (19)
In 89), a carbon black tumbling granulated product is impregnated with a phenol resin, and then fired in an inert atmosphere to form vitreous carbon on the surface layer of the carbon black granules to form a granular heat insulating material. Is described. Also, Tokuho 8
Japanese Patent No. 5722 describes that a heat insulating material is obtained by mixing carbon black and pulp, shaping the mixture with an organic binder, and firing the mixture. However, these have a thermal conductivity of 0.38 to 0.44 (Kcal / m · h · ° C.).
at 100 ° C.), and other heat-insulating materials, for example, heat-insulating materials using ceramic fibers are 0.04 to 0.06.
(Kcal / m · h · ° C. at 100 ° C.), it does not sufficiently meet the recent demand for energy saving. Further, granular products do not sufficiently respond to the point that they do not have a self-forming property and cannot be freely shaped, or to a request for reducing environmental pollution. TECHNICAL FIELD The present invention relates to a carbon black aggregate having significantly lower thermal conductivity than conventional carbonaceous heat insulating materials and low dust generation during furnace construction and furnace disassembly.

[0004]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies on the reduction of the thermal conductivity of carbon black aggregates. It has been found that it exhibits a significantly lower thermal conductivity than the granular carbon black that has been used. That is, the present invention provides a thermal conductivity of 0.100K.
cal / m · Hr · ° C. or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
In the carbon black aggregate of the present invention, a large number of powdery carbon black particles as raw materials aggregate to form an integral shape. The size of the aggregate in the present invention is such that the size can be determined with the naked eye, but is preferably 1 cc or more, more preferably 5 cc or more. Even if a large number of carbon black particles are aggregated, for example, in the case of a conventional wet or dry granulated product, a large number of particles are not aggregated as in the present invention, but one unit which is one unit of aggregation. Each grain does not have such a size that the shape can be confirmed with the naked eye. For this reason, as is clear from a comparative example described later, the heat insulating effect as in the present invention cannot be exhibited.

The degree of aggregation is defined as the density of the aggregate (the value obtained by dividing the mass of the aggregate by the volume of the aggregate is 1.2 to 6) with respect to the bulk density of the carbon black powder as the raw material of the aggregate. Times,
Preferably, it is 2.5 to 5 times, since the heat insulating effect is particularly high. Although there is no particular limitation on the method for producing such a carbon black aggregate, in order to obtain a carbon black aggregate having an optimal thermal conductivity, carbon black is put into a mold, pressurized by means such as a piston, and carbon black is pressed. It is preferable to assemble into a carbon black aggregate. For example, examples of the pressurizing device include a hydraulic press, a mechanical press, and an air cylinder press. The type in which the carbon black is put during pressurization may be appropriately selected according to the form of the target aggregate or the heat insulating material using the same. The material of the mold is not particularly limited, and any material that can withstand the applied pressure, such as metal, resin, and ceramic, can be used without any particular limitation. Moreover, in order to prevent breakage when the obtained carbon black aggregate is removed from the mold, the surface of the mold may be coated so that the aggregate can be easily removed from the mold.

[0007] The shape of the carbon black aggregate in the present invention is preferably a shape capable of filling a space, for example, a rectangular parallelepiped or a cube. This is because even if heat conduction due to convection within the aggregate is reduced by the present technology, if there is a space between the aggregates, there is heat transferred by convection generated in this space.

[0008] The carbon black that can be used in the present technology is not particularly limited, but carbon black produced by the furnace method is preferable because it has a small particle diameter and can reduce the thermal conductivity. . Among these, more preferably, the particle diameter is 80 nm or less, and the DBP oil absorption is 40
(Ml / carbon black 100g) 150 or more (ml
/ Carbon black 100 g) or less, more preferably, a particle diameter of 20 nm or less, and a DBP oil absorption of 100 g or less.
(Ml / 100 g of carbon black) or more has a thermal conductivity of less than 0.03 (Kcal / m · h · ° C.) and is preferable as a carbon black applicable to the present technology. Further, if necessary, the strength of the aggregate can be increased by mixing the carbon black powder with an organic substance, molding the resultant, or coating or packaging the surface of the aggregate with an organic substance.

Example 1 A carbon steel mold manufactured by Yuken Co., Ltd. (inner method 200 mm × 200 mm,
(360 mm height) carbon black "# 9" manufactured by Mitsubishi Chemical Corporation.
90 "(bulk density 0.097g / cc) 0.5kg
It was set on a hydraulic press manufactured by Yuken Co., Ltd. Pressure 1
0.4kgf / cm ^TwoAnd press the aggregate (density 0.41
7 g / cc). Cut this assembly 20mm in thickness
Cut, the inner size 200mm x 200mm, height 20mm
It was placed in a resinous frame. Collection of carbon black in this frame
The union is wrapped in a 30 μm thick polyethylene film,
A sample for measuring the thermal conductivity was used. This sample was subjected to JIS A-14
Thermal Conductivity Measurement System (AUTO)
-Lambda series HC-072)
The conductivity was measured. The measurement conditions were hot plate temperature 3
7.7 ° C, cold plate temperature 10.0 ° C, average measurement
It was measured at a temperature of 23 ° C. As a result, 0.0239 Kca
1 / m · h · ° C.

Example 2 Example 1 was repeated except that the pressure was 20.8 kgf / cm ^2.
An assembly was produced in exactly the same manner as described above, and the thermal conductivity was measured. As a result, it was 0.0260 Kcal / m · h · ° C. Example 3 An assembly was produced in exactly the same manner as in Example 1 except that the carbon black was changed to "# 45" manufactured by Mitsubishi Chemical Corporation, and the thermal conductivity was measured. As a result, 0.0502 Kcal / m
H · ° C.

Example 4 An assembly was prepared in exactly the same manner as in Example 3 except that the pressure was changed to 20.8 ° f / cm ^2, and the thermal conductivity was measured. As a result, it was 0.0527 Kcal / m · h · ° C. The results are shown in Table 1.

[0012]

[Table 1]

[0013]

According to the present invention, by performing a specific carbon black aggregate state, the thermal conductivity is extremely low,
It is possible to produce a carbon black aggregate having a low dust generation property during furnace construction and furnace dismantling.

Claims (3)

[Claims] 1. Thermal conductivity 0.100 Kcal / m · Hr ·
A carbon black aggregate having a temperature of not more than ° C. 2. The carbon black aggregate according to claim 1, wherein the carbon black is a furnace black obtained by a furnace method. 3. A heat insulating material comprising the carbon black aggregate according to claim 1.