JPS60115665A - Method for reforming carbon black - Google Patents

Abstract

PURPOSE:To reform carbon black to have excellent properties as an electrically conductive material, by heat-treating carbon black in the presence of a specified compd. in an inert atmosphere. CONSTITUTION:Carbon black (pref. one having a large surface area, pref. 800m<2>/ g or above, DBP absorption of 250ml/100g or above and high electrical conductivity) is heat-treated at 250-800 deg.C in the presence of a higher fatty acid (e.g. palmitic or oleic acid), a base (e.g. lutidine), an arom. compd. (e.g. t-stilbene), an ester (e.g. tristearin), a sulfur compd. (e.g. dephenyl disulfide) or a polyol (e.g. polyglycerol) and air-cooled, thus obtaining reformed carbon black having excellent properties as an electrically conductive material. It is desirable that when raw carbon black contains a large quantity of metal, it is treated with a mineral acid to remove the metal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for modifying carbon black (hereinafter also referred to as CB).

CB has recently been developing high voltage cables, surface heating element 1 communication cables,
& i-wave tape, video disc, @ & i-wave shielding material,
Antistatic materials, conductive paints, toner for xerography, etc.
It is being developed as an organic conductive material.

When developing these new materials, ``ζ'' is not only about CB itself, but also about the optimal control and design of physical chemical mechanisms between CB and the polymers, monomers, and other compounds that are mixed with it to impart properties. has become an important R topic.

The CB used for the above purpose is preferably a highly conductive CB, such as an acetylene blank, a conductive furnace blank, a channel black, a by-product carbon black from a partial oxidation gas process, and the like.

Acetylene blanks are obtained from high purity acetylene gas by thermal or furnace methods. Conductive Furnace Black is a blank with high surface area and high oil absorption (DBP) obtained by the furnace method, which has a relatively small secondary particle size and contains many porous or elastomer-type particles. ~Hundreds of fused ゛ (high conductivity is exhibited even in resin when a strafute structure is developed.Channel Silk is CB obtained by the channel method.By-product CB is partially burned from oily raw materials such as aquatic gas etc. This is the CB obtained when generating .

These CBs contain small amounts of hydrogen and oxygen, which are present as functional groups on or near the surface of the CB. For example, phenol (>OH1, weakly acidic), quinone (>-0) carboxylic acid, COS11, strongly acidic), lactone (>C0
0-), active hydrogen (>-II), and the like. These generally trap electrons and act to reduce conductivity, and are thought to affect the affinity when mixed with resin and molded.

When resin, especially PVC, is kneaded with highly structured CB, self-heating occurs, which promotes thermal decomposition of PVC, resulting in quality deterioration of molded products.

Also, depending on the type of CB, trace amounts of metal salts may be added for quality control, or these may be mixed in during the manufacturing process. These sometimes have undesirable effects on the material. This metal can be removed by acid treatment, but this results in a decrease in the pH of CB, and when it is kneaded with PVC, for example, the stability of PVC decreases.

As a result of studies on the manufacturing method of CB, which has excellent properties as a conductive material, CB was heated at 250 to 800°C in the presence of higher fatty acids, bases, aromatic compounds, esters, sulfur-containing compounds, or polyols under an inert gas atmosphere. It has been found that CB excellent as a conductive material can be obtained by heat treatment preferably at 300 to 400°C for 1 to 10 hours.

Although any CB can be used as a raw material, for example, the above-mentioned CB is used. In particular, the surface area is large, preferably 800 rrl/g or more DBP absorption i!
CB with high conductivity of 250 ml/100 g or more is preferably used.

If CB contains a large amount of metal, C
B is treated with a mineral acid such as hydrochloric acid or sulfuric acid to perform ζ-demetallization. Alternatively, after heat treatment is performed first, demetallization is performed using a mineral acid. This treatment is usually carried out at a concentration of 1 to 10% for 1 to 10 hours, if necessary, at a temperature of 200° C. or lower. After treatment, it is washed with water, and if necessary, it is neutralized with aqueous ammonia and washed with water.

Examples of higher fatty acids include fatty acids having 7 to 23 carbon atoms, such as valmitic acid, lauric acid, isostearic acid, 1.2-
Hydroxystearic acid, hehenic acid.

Saturated fatty acids such as caprylic acid and unsaturated fatty acids such as oleic acid are used.

Examples of bases include 2.3 benzopyridine, lutidine, stearylamine, indole, hexamethylenediamine, triethanolamine, 1.3 diphenylguanidine, ammonia, ammonia and stearic acid, ε-caprolactam, melamine, diphenylthiourea, glutamic acid, etc. Examples of aromatic compounds include t-stilbene, α
- Phenylcinnamic acid, methyl cinnamate, styrene, biphenyl, anthracene, bishyenol A, etc., and the esters include triallyl trimellitate, glyarol monostearate, tristearin, PEG monostearate, stearyl ricinoleate. , monomethyl maleate, etc., and sulfur-containing compounds include octadecyl thiodiglycolate, diphenyl disulfide, benzothiophene, 2-naphthalethiol, 2-mercaptobenzothiazole, 4.4' dithiomorpholine,
Examples of the polyol include tetramethylthiuram disulfide and the like, and examples of the polyol include polyglycerin and 1.6 hexanediol.

These are used in an amount of 1 to 10% of CB.

CB and the above-mentioned additive compound are usually mixed well prior to heat treatment and then heat treated. A rotary kiln, for example, can be used as a processing device that can use a solvent during mixing if necessary.

After heat treatment, the desired product is obtained by natural cooling.

Modified CB with excellent properties can be obtained by the method of the present invention. Although its mechanism of action is not clear, CB
As mentioned above, the back surface has functional groups, which are partially decarboxylated and decomposed by the treatment of the present invention, and partially esterified to improve the pH, reduce the active sites on the surface of CB, and increase the affinity for the resin. It is estimated that this will increase -) -12'l Musu way 1 conflict meeting's coffee face drunkenness) It is estimated that it gives t, -117, Oka 2 grade.

Aspects of the present invention will be illustrated by examples.

Example 1 60k of 5% hydrochloric acid was placed in a 10 l glass flask, and carbon black (Black Pearl 2) shown in Table 1 was added to it.
000 (manufactured by Cabot) and stirred gently at 95°C for 6 hours. After cooling, filtration and washing with water are repeated until the chloride ion concentration in the filtrate is below IOppm, and the pH is adjusted to 10 by adding 5% aqueous ammonia. The filtration and water washing are repeated until the chlorine ions are reduced to 1 ppm or less, and the resulting filter cake is vacuum dried to obtain a demetallized carbon blank. The physical properties of the obtained carbon black are
Shown in the table.

Table 1 Table 3 * In this example, 2,3-benzopyridine is dissolved in the CB slurry after mineral acid treatment, water washing, neutralization, and water washing, and after mixing, filtered and vacuum-dried CB is added as a new additive. Heat treated without adding.

Example 4 The results shown in Table 4 were obtained in the same manner as in Example 3, except that the additives shown in Table 4 were used instead of 2.3 benzopyridine.

Table 4 Additive Treatment Volume solidity Temperature pH Total acid amount Resistance Thermal stability (%) °C) (ΩcIl) Rutin y 330 B, 7 69 10.6 12.0
/194 Stearyl 330 9.4 41 11.1
9.0/194 Amine Indole 330 8.7 71 10.4 10.
5/191 Heki'tfi Chile 330 8.7 59 1
1.0 9.5/190 Diamine Triethano-3308,16610,014,0/19
3 amine 1.3 diphenylene 350 8.9 53 12.6 1
0.0/191 Luguanidine 7” 330 9.3 39 8.5 11.
0/194 ammonia + 350 9.7 48 8.
5 15.0/192 Guider arylic acid-brolac 330 8.7 51 B, 9 13.0
/192.7 Mu J Rami: i 330 B, 5 61 B, 4 10.5
/193sym Dipheni 330 8.7 55 B,
7 11.0/193 ruthiourea*Ammonia was supplied at 2.3 N 12 /h to a rotary kiln filled with 200 g of CB.

** 5% stearic acid was mixed and treated in the same manner as ammonia.

Claims (1)

[Claims] 1. A carbon blank is heat-treated at a temperature of 250 to 800°C in an inert gas atmosphere in the presence of a higher fatty acid, a base, an aromatic compound, an ester, a sulfur-containing compound, or a polyol. A method for modifying carbon black. 2. The method of claim 1, wherein the carbon black is treated with a mineral acid prior to said treatment. 3. A method according to claim 1, wherein after said treatment the carbon blank is treated with a mineral acid.