JPH09142818A - Carbon black molded body - Google Patents

Abstract

(57) [Summary] [Problem] To obtain a carbon black press-molded body excellent in compactness and suitable for handling without impairing the basic characteristics of carbon black. SOLUTION: The density ρ (g / cc) is ρ = 8.190 × 10 ⁻³ D−3.824 × 10 ⁻³ L +
0.516 or more, ρ = 3.265 × 10 ⁻³ D−3.334 × 10 ⁻³ L +
1.173 or less (however, the arithmetic average particle diameter of carbon black by an electron microscope is D (nm), and the DBP oil absorption is L (ml / 1
00g)).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carbon black molded body.

[0002]

2. Description of the Related Art At present, carbon black manufactured by a furnace method (hereinafter referred to as "furnace black") is distributed as a mainstream in the carbon black market. Lamp black and thermal black have historically existed as carbon black, but nowadays most of the products on the market are used in the furnace method developed by Philips in 1942, that is, in the furnace heated above 1300 ° C. It is a method of obtaining carbon black by spraying oil. This is not only excellent in productivity such as high yield, but also characteristics of furnace black,
In particular, it is considered that this is due to the fact that particles having a small particle size and structure can be obtained, and the blackness of inks and paints can be increased and excellent performance can be exhibited.

On the other hand, the above-mentioned furnace black tends to be difficult to disperse in a vehicle due to its small particle size, small structure and small amount of surface adsorbed substances. Furthermore, due to the small particle size and low bulk density, there are problems such as dust generation and contamination, and environmental problems during use and transportation are great. That is, carbon black produced by the furnace method usually has an extremely low bulk density of about 0.1 g / cc immediately after production. Due to this low bulk density value, the cost of packaging bags, storage costs in warehouses, transportation costs in trucks / wagons and ships are high, and there are many dusts during distribution and use, and it is easy to pollute the environment .

In order to solve such a problem, a dry granulation product or a wet granulation product called a bead product is usually used. The bead product has a bulk density of 0.3 to 0.5 g / cc, which is considerably higher than that of untreated carbon black.
However, it cannot be said that suppression of dust generation at the time of measurement and suppression of powdering of the granulated material at the time of transportation are sufficient. Further, granulation deteriorates dispersibility in a vehicle such as varnish or resin, which is a raw material of paint or ink, and beads may not be used in some cases. According to the knowledge of the present inventors, it is considered that the bead product is granulated while carbon black particles having a long structure structure are entangled with each other in the granulation process, so that the bead product may have poor dispersibility. Can be As described above, the handling properties of carbon black, particularly furnace black, which can be made to have a small particle size, that is, ease of handling, and dispersibility in a vehicle,
There is a trade-off, and it has been considered extremely difficult to simultaneously solve handling and dispersibility. For example, "Carbon Black Handbook <Third Edition>" (P.563) edited by Carbon Black Association states, "Carbon black with low contamination and excellent handling properties, easily dispersible carbon for further improving the production and quality of ink. The development of black is likely to be a major need. The handling property and dispersibility of carbon black are in a trade-off relationship, and it is necessary to improve across the boundaries of surface chemistry, rheology, carbon black form, packaging, shipping form, etc. ], It is widely recognized in the carbon black industry that it is extremely difficult to simultaneously solve handling and dispersibility, and various proposals have been made. However, there is no example of solving these two problems at the same time.

Regarding carbon black such as lamp black that existed before the appearance of furnace black, for example, in British Patent No. 551,862 (filed in 1941), lamp black was press-degassed to improve bulk density and handleability. It has been attempted to do so, and British Patent 618,955 (filed in 1946) proposes a device for performing press degassing in British Patent 551,862.

German Patent No. 1302382 (19)
(Filed in 1966) states that a lamp black molded body of 0.160 to 0.480 g / cc was obtained by an apparatus for increasing the density by pressing.

As for the furnace black, for example, in Japanese Patent Laid-Open No. 3-259962, an aqueous slurry of carbon black is suction-filtered and then dried in a block,
Attempts have been made to improve the handleability by applying an aqueous solution of casein / starch / polyvinyl alcohol and styrene / butadiene latex or acrylic latex to the surface of the block. However, in this method, it is necessary to prepare a slurry of ultrafine carbon black, and then filter and dry the slurry, which requires a great deal of labor and cost. In addition, the obtained block is considered to have greatly reduced dispersibility.

Further, in Japanese Unexamined Patent Publication No. 6-122111, a carbon black powder is charged into an airtight molding container, subjected to decompression treatment, and then the pressure in the container is restored to normal pressure to obtain a molding. However, the molding pressure applied by the reduced pressure is lower than the atmospheric pressure (about 1.03 kg / cm ² ),
Bulk density cannot be increased as transportation costs and warehouse costs are reduced. It was also found that large irregularities were generated on the surface of the obtained molded body. This is considered to be because the carbon black, which is a bulky powder, is compacted due to a pressure difference, and a part of the charged carbon black is blown off. For this reason, powdering and breakage occur during transportation, and the handling property (compactness) and the dispersibility are not simultaneously solved. As described above, furnace black solves the trade-off between handleability and dispersibility generally recognized in the past, and no technology has been found that satisfies both at the same time, and powdered or granular products are still available. However, the above problems such as dust could not be solved. In other words, by improving storage / transportation costs, handling, and the environment, carbon black is impaired in its basic properties when used in paints, inks, resin coloring, rubber reinforcement, and other applications. It cannot be accepted and cannot be accepted by the market.

[0008]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve the above problems. As a result, by controlling the molding density, the particle size, and the DBP oil absorption amount, which are the densities of the molded product obtained by pressure-molding carbon black, in a specific relationship, it is possible to satisfy the improvement in bulk density and dispersibility at the same time. The present inventors have reached the present invention by obtaining surprising findings. Further, it was also surprisingly found that this molded product can improve jetness when used as a paint or the like, compared with the carbon black powder (loose product) as a raw material. That is, according to the present invention, the density ρ (g / cc) is ρ = 8.190 × 10 ⁻³ D−3.824 × 10 ⁻³ L +
0.516 or more, ρ = 3.265 × 10 ⁻³ D−3.334 × 10 ⁻³ L +
1.173 It exists in the carbon black pressure-molded body represented by the following.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
First, examples of the carbon black used in the present invention include carbon black produced by a furnace method and acetylene black. Of these, particularly when furnace black produced by the Fars method is used, a very remarkable effect is exhibited in maintaining its dispersibility. Furthermore, the effect of improving jetness is also great. Further, carbon black produced by these methods may be used after post-treatment with various oxidizing agents or the like. The particle size of the carbon black is not particularly limited, but is particularly effective in improving the dispersibility and handleability in a small particle size range of 1 to 60 nm, and more preferably in the range of 1 to 50 nm. I do. Carbon black having a fine particle diameter in such a range has strong cohesion between carbon blacks, and is particularly difficult to disperse when producing inks, paints, colored resins, rubbers, and the like. Another advantage is that the more difficult these carbon blacks are to disperse, the more the advantages of the present technology can be exhibited.

In the present invention, these carbon blacks are molded under pressure. At this time, a mold of any material may be used as long as it has a strength that can withstand the pressure applied during molding. For example, the metal mold is S
Stainless steel molds such as US304 and SUS316, and super steels such as tungsten carbide can be used. Further, as the resin mold, fluororesin such as polytetrafluoroethylene (PTFE), polytrifluorochloroethylene (PCTFE), polytetrafluoroethylene / hexafluoropropylene (FEP) (trademark: "Teflon") ) Molds, nylon, polyethylene, polycarbonate, plastics such as phenol resin, and FR such as CFRP and GFRP as composite materials
Examples of P and ceramic molds include alumina, zirconia, and mullite. The size of the mold is not limited, but practically 1 cc or more, preferably 100 c
and those of c or more. If it is less than 1 cc, transportation becomes complicated. If necessary, a large molded body may be produced, cut into a suitable size, and transported and used as an aggregate.

The press machine used for pressurization includes a hydraulic mechanical press machine, a hydraulic hand press machine, a mechanical press machine,
Any press molding machine may be used as long as it can be press molded, such as an air cylinder press.

The shape of the mold is not particularly limited, and it can be formed into a columnar body having a triangular or other polygonal cross section, particularly a cubic or rectangular parallelepiped molded body, according to the desired shape of the molded body. Is also suitable.

The carbon black is put into the above-mentioned mold and molded by pressing. At this time, the density of the obtained molded body is set to the following specific value. That is, the density ρ (g / c
c), ρ = 8.190 × 10 ⁻³ D−3.824 × 10 ⁻³ L +
0.516 or more, ρ = 3.265 × 10 ⁻³ D−3.334 × 10 ⁻³ L +
1.173 or less. More preferably, ρ = 8.686 × 10 ⁻³ D−4.031 × 10 ⁻³ L +
0.543 or more, ρ = 3.123 × 10 ^-3 D-3.189 × 10 ^-3 L +
1.072 or less is preferable. In each of the above formulas, D (nm) is the arithmetic mean particle size of carbon black by an electron microscope, L
(Assumed to be ml / 100 g) is the DBP oil absorption.

Here, the DBP oil absorption is JIS K62.
It is a value measured by a method based on 21-1982. The particle size of the carbon black is a value measured by the method described below. Carbon black is put into chloroform, and ultrasonic waves of 200 KHz are irradiated for 20 minutes to disperse the carbon black, and then the dispersed sample is fixed to a support film. This is photographed with a transmission electron microscope, and the particle diameter is calculated from the diameter on the photograph and the magnification of the photograph. This operation is performed about 1500 times, and it calculates | requires by the arithmetic mean of those values. By setting the density within the above range, a molded article excellent in handleability can be obtained without impairing basic characteristics of carbon black such as dispersibility in a vehicle. In addition, ink,
It also has the surprising effect that the jetness when used in paints and the like can be improved compared to the raw material powder. These effects are particularly remarkably exhibited in the range described as the more preferable range described above.

The carbon black molding of the present invention has a pulverization rate of 40% or less, more preferably 20% or less. The eruption rate can be determined by the measuring method described in Examples below. By setting the powdering ratio to 40% or less, powdering due to external force such as vibration or friction applied to the molded body during transportation can be prevented, and handling properties are particularly excellent. Further, the ratio of the bulk density of the powdery carbon black as a raw material to the bulk density of the carbon black molded body (hereinafter, also referred to as “bulk density ratio”) is 2.
It is good to set it to 5 times or more and 8 times or less, more preferably 3 times or more and 7 times or less. If this bulk density ratio is lower than 2.5,
The compactness of the molded body tends to decrease. On the other hand, when the bulk density ratio exceeds 8, the dispersibility tends to decrease.
When the bulk density ratio is 2.5 or more and 8 or less, compactness and dispersibility are simultaneously satisfied in an extremely preferable range. The pressure at the time of pressure molding (molding pressure) is ² Kgf / cm ² or more and 500 Kgf / cm ² or less, and more preferably 5 Kgf /
It is preferable to set it to be not less than cm ^{2 and not} more than 400 Kgf / cm ² .
If the molding pressure is less than ² kgf / cm ² , compactness tends to decrease and the pulverization rate tends to increase. On the other hand, when the molding pressure is higher than 500 Kgf / cm ² , the dispersibility may not be sufficient in a disperser used in the production of ordinary inks and paints. On the other hand, even if the pressure is further increased, the effect of improving compactness can hardly be obtained. Therefore, as a carbon black molded body used when industrially producing ink, paint, colored resin, rubber, etc.,
It is suitable to perform pressure molding at ² Kgf / cm ² or more and 500 Kgf / cm ² or less. The shape of the carbon black molded body is not particularly limited, but is preferably a columnar body having a polygonal cross section, more preferably a rectangular parallelepiped or a cube. A molded article having such a shape is generally a rectangular parallelepiped truck, freight car, or warehouse for transporting carbon black, and can fill these spaces without gaps. As a result, transportation costs and warehouse storage costs can be efficiently reduced. Hereinafter, the present invention will be described in more detail with reference to Examples.

[Examples] The carbon blacks shown in Table 1 were used, and the press machine was 37 ton manufactured by Oji Machine Industry Co., Ltd.
Using a four-column single-acting hydraulic press (ram diameter 152.4 mm), the mold is made of SUS304 (inner method 70 mm x 70 m).
m, height 40 mm, manufactured by Mitsubishi Kasei Engineering Co., Ltd.) was used to press-mold carbon black.

[0016]

[Table 1]

The method for measuring the ink screen residual ratio for testing the dispersibility of carbon black during the production of ink is shown below. To a stainless steel container (diameter 11 cm, height 18.5 cm) of about 1.8 liters, 480 g of Reductus # 220 (manufactured by Kyoishi Co., Ltd.) and 120 g of carbon black molded body or carbon black granulated product were added. Stirrer blade (4 set in TK Auto Homo Mixer SL10A (manufactured by Tokushu Rika Kogyo))
A single blade and a blade diameter of 4.5 cm) were inserted 2 cm above the bottom surface of the stainless steel container. 5000r.pm stirring blade
For 1 hour. From this, 50 g was taken and filtered through a 325 mesh (opening: 46 μm) stainless steel sieve. After filtration, about 200 cc of light oil was sprinkled on the wire mesh surface for washing. This sieve was placed in a dryer set at 150 ° C. for 1 hour and dried. After removing from the dryer and cooling, the weight of the sieve was measured. The weight (Ag) of the carbon black remaining on the sieve was measured by subtracting the weight of the sieve measured in advance, and the residual sieve ratio was calculated from the following equation. Residual sieving rate (%) = (A × 600 / (50 × 120)) ×
100

When measuring the density, the length, width, and thickness of the rectangular parallelepiped are measured with a caliper, and the volume (c
c) was calculated. Moreover, the weight (g) of the molded body was measured with an electronic direct-reading type balance. The density (g / cc) of the molded body was calculated from the weight and volume of the molded body.

The method of measuring the pulverization rate is described below. Carbon black pressure molded product is 25 ± 1g (W) 0.01g
Up to 200 in diameter according to JIS K-6221
mm, open with 1 mm opening. A saucer and a lid are attached to this sieve, and shaken while being hit with a shaker according to JIS K-6221 for 20 seconds. Remove the saucer from the shaker, accurately weigh the carbon black in the saucer to 0.01 g, and weigh it after shaking (W _R ).
And the pulverization rate was calculated by the following formula. Powdering rate _{(%) = (W R /} W) × 100 with (Comparative Example) powdered products of the same brand used in Examples and granulated product, measurement of bulk density as described in Example, ink sieve The residue and pulverization rate were measured. Regarding # 45 (carbon black manufactured by Mitsubishi Chemical Co., Ltd.) and # 990 (carbon black manufactured by Mitsubishi Chemical Co., Ltd.), Japanese Patent Application Laid-Open No. 6-1
The decompressed / recompressed product described in No. 22111 was prepared and described in Comparative Example. (Judgment Criteria for Results) Tables 2 to 7 show the measurement results of Examples and Comparative Examples, and the comprehensive judgment results obtained by comprehensively judging compactness and dispersibility, and further compactness and dispersibility. Indicated. Here, as a criterion for compactness, a bulk density of a powdery product is higher than that of the powdery product, and a bulk density of a granulated product or less is Δ, and a bulk density of which is higher than the granulated product is O. In addition, as a criterion for determining the dispersibility, a dispersant having a dispersibility equal to or less than that of the granulated product is used. And In addition, as a criterion for comprehensive judgment, one with either compactness or dispersibility is × is compactness, dispersibility is excellent in feeling when used ○ Compactness, dispersibility, and feeling used are Especially excellent was marked with ◎.

[0020]

[Table 2]

[0021]

[Table 3]

[0022]

[Table 4]

[0023]

[Table 5]

[0024]

[Table 6]

[0025]

[Table 7]

(Discussion of Results) (1) Comparing Example 1-2 with Comparative Example 1-9, the bulk densities were 0.562 g / cc and 0.488 g / cc.
Although the bulk density of No. 2 is higher than that of Comparative Example 1-9, the ink screen residue, which is a factor of dispersibility, is 11.0% in Example 1-2, and Comparative Example 1-9. Then 78
%, And the molded body of Example 1-2 maintains the dispersibility before molding. Comparing Example 1-8 and Comparative Example 1-9, the bulk densities are 1.050 g / cc and 0.488 g / cc, and the bulk density increase of about 2 times is achieved in Example 1-8. However, the ink screen residue, which is a dispersibility factor, was 74.0% in Example 1-2 and 78.% in Comparative Example 1-9.
It is 0%, and Example 1-8 shows a dispersibility equal to or higher than that of Comparative Example 1-9. As can be seen from the above, according to the present invention, it is possible to obtain a carbon black excellent in both compactness (handling property) and dispersibility, which are conventionally considered to be in a trade-off relationship.

(2) Comparing Example 2-2 with Comparative Example 2-9, the bulk densities are 0.385 g / cc and 0.393 g / cc, and the bulk density of Example 2-2 is Comparative Example 2- Despite being about the same as the bulk density of No. 9, the ink screen residue, which is a factor of dispersibility, was 0.7% in Example 2-2 and 100% in Comparative Example 2-9. The molded body of 2-2 maintains the dispersibility before molding. Example 2-7 and Comparative Example 2-9
Comparing the two, the bulk densities are 0.850 g / cc and 0.393 g / cc
cc, which achieved a bulk density increase of about 2.2 times, but the ink sieve residue, which is a factor of dispersibility, was used in Example 2-
No. 7 is 98.0% and Comparative Example 2-9 is 100%, and Example 2-7 shows dispersibility equal to or higher than that of Comparative Example 2-9. As can be seen from the above, according to the present invention, it is possible to obtain a carbon black excellent in both compactness (handling property) and dispersibility, which are conventionally considered to be in a trade-off relationship.

(3) Comparing Example 3-2 with Comparative Example 3-10, the bulk densities are 0.240 g / cc and 0.303 g / cc, and the bulk density of Example 3-2 is Comparative Example 3- Despite having the same bulk density as that of 10, the ink screen residue, which is a factor of dispersibility, is 0.25% in Example 3-2, and Comparative Example 3-
In No. 10, it is 84.5%, and the molded product of Example 3-2 maintains the same dispersibility as that before the molding. Example 3
When -9 and Comparative Example 3-10 are compared, the bulk density is 0.75.
0 g / cc and 0.303 g / cc, Example 3-9 about 2.5
Although the bulk density is doubled, the ink screen residue, which is a dispersibility factor, is 77.0% in Example 3-9 and 84.5% in Comparative Example 3-10. Three
-9 shows dispersibility equal to or higher than that of Comparative Example 3-10. As can be seen from the above, according to the present invention, it is possible to obtain a carbon black excellent in both compactness (handling property) and dispersibility, which are conventionally considered to be in a trade-off relationship.

(4) Comparing Example 4-2 with Comparative Example 4-9, the bulk densities are 0.433 g / cc and 0.497 cc, and the bulk density of Example 4-2 is that of Comparative Example 4-9. Ink sieve residue, which is a factor of dispersibility, is 0.3% in Example 4-2 and 1 in Comparative Example 4-9, although it is similar to the bulk density.
It is 00%, and the molded body of Example 4-2 maintains the same degree of dispersibility as that before molding. Comparing Example 4-8 with Comparative Example 4-9, the bulk densities were 0.990 g / cc and 0.4.
It was 97 g / cc, and in Example 4-8, a bulk density increase of about 2 times was achieved, but the ink sieve residue, which is a factor of dispersibility, was 99.0% in Example 4-8, and Comparative Example 4 -9 is 100%, and Example 4-8 is Comparative Example 4-9.
It shows dispersibility equal to or higher than. As can be seen from the above, according to the present invention, it is possible to obtain a carbon black excellent in both compactness (handling property) and dispersibility, which are conventionally considered to be in a trade-off relationship.

(5) Comparing Example 5-2 with Comparative Example 5-7, the bulk densities were 0.522 g / cc and 0.517 g / cc, and the bulk density of Example 5-2 was Comparative Example 5- Despite being higher than the bulk density of No. 7, the ink screen residue, which is a factor of dispersibility, is 0.5% in Example 5-2, and Comparative Example 5-
In Comparative Example 7, the ratio is 80%, and the molded product of Example 5-2 maintains the dispersibility before molding. Example 5-7 and Comparative Example 5
Comparing -8, the bulk density is 0.945g / cc and 0.51
It was 7 g / cc, and in Example 5-7, a bulk density increase of about 1.8 times was achieved, but the ink sieve residue, which is a factor of dispersibility, was 79.5% in Example 5-7. In Example 5-8, it was 80.0%, and in Example 5-7, Comparative Example 5 was used.
The dispersibility is equal to or higher than −8. As can be seen from the above, according to the present invention, it is possible to obtain a carbon black excellent in both compactness (handling property) and dispersibility, which are conventionally considered to be in a trade-off relationship.

(6) Comparing Example 6-2 with Comparative Example 6-9, the bulk densities are 0.345 g / cc and 0.364 g / cc, and the bulk density of Example 6-2 is Comparative Example 6- Despite being about the same as the bulk density of No. 9, the ink screen residue, which is a factor of dispersibility, was 0.50% in Example 6-2 and 56.7% in Comparative Example 4-9. The molded body of Example 6-2 maintains the same dispersibility as that before molding. Comparing Example 6-7 with Comparative Example 6-8, the bulk densities were 0.804 g / cc and 0.364 g / cc, and Example 6-7 achieved about 2.2 times the bulk density increase. However, the ink screen residue, which is a factor of dispersibility, is 28.1% in Example 6-7 and 56.7% in Comparative Example 6-8, and Example 6-7 is Comparative Example 6- It shows a dispersibility of about half of 8. As can be seen from the above, according to the present invention, it is possible to obtain a carbon black excellent in both compactness (handling property) and dispersibility, which are conventionally considered to be in a trade-off relationship.

Industrial Applicability According to the present invention, a carbon black molded article which is excellent in compactness and suitable for handling can be obtained without impairing the basic properties of carbon black.

Claims (9)

[Claims] 1. The density ρ (g / cc) is ρ = 8.190 × 10 ⁻³ D−3.824 × 10 ⁻³ L +
0.516 or more, ρ = 3.265 × 10 ⁻³ D−3.334 × 10 ⁻³ L +
1.173 or less (however, the arithmetic average particle diameter of carbon black by an electron microscope is D (nm), and the DBP oil absorption is L (ml / 1
00g)). 2. The density ρ (g / cc) is ρ = 8.686 × 10 ⁻³ D−4.031 × 10 ⁻³ L +
0.543 or more, ρ = 3.123 × 10 ^-3 D-3.189 × 10 ^-3 L +
1.072 or less (provided that the arithmetic average particle diameter of carbon black by an electron microscope is D (nm), and the DBP oil absorption is L (ml / 1
00g)). 3. The carbon black pressure-molded article according to claim 1, wherein the carbon black is obtained by a furnace method. 4. The particle size of carbon black is 1 nm or more and 6
It is 0 nm or less, The carbon black press-molding body in any one of Claims 1-3 characterized by the above-mentioned. 5. The carbon black pressure-molded product according to claim 1, which has a pulverization rate of 40% or less. 6. The carbon black pressure-molded article according to claim 1, wherein the bulk density of the carbon black pressure-molded article is 2.5 times or more and 8 times or less the bulk density of the raw material carbon black. . 7. The pressure during pressure molding of carbon black is 2
The carbon black pressure-molded product according to any one of claims 1 to 6, which has a Kgf / cm ² or more and 500 Kgf / cm ² or less. 8. The carbon black pressure-molded article according to claim 1, which is a columnar body having a triangular or other polygonal cross section. 9. The carbon black pressure-molded product according to claim 8, wherein the shape of the molded product is a cube or a rectangular parallelepiped.