Conductivity carbon black pigments

Vulcani2ed mbber is an insulator (volume resistivity is 10 Q-cm), and the static generated by mbber tires created serious problems in vehicles until the introduction of electrically conductive carbon black as a reinforcing pigment. An excellent correlation was found between the potential generated and the resistivity of the tires (127,128) (see Rubber natural). 

Conductivity in plastic coatings is achieved through the use of a conductive pigment, most often conductive carbon black. Conductivities of the order of 1 Mfl/cm2 are required for effective transfer efficiencies of subsequent topcoat applications. Without the use of a conductive primer, plastics in themselves would not be conductive, and hence would be very unreceptive to topcoat transfer efficiencies of greater than 20 percent. 

For specialised applications where electrical conductivity is required, such as antistatic flooring or shielding of electromagnetic induction, specific carbon black pigment/filler is used. Copper and nickel metal powders have also been studied (112). A review is available of the electrical properties of polymers filled with different types of conducting particles (416). 

Mitsubishi Carbon Black . [Mitsubishi Kasei] Carbon black pigments for inks, plastics, paints conductive grades avail. 

Acetylene black n. Particularly pure form of carbon black pigment, made by the controlled combustion of acetylene in air under pressure. It is graphitic in nature and has high electrical conductivity. Don-net J-B, Wang M-J (1993) Carbon black. Marcel Dekker, New York. 

It is much more complicated to disperse ICP powder in conventional thermoplastic polymers than is the case with, for example, pigments or conductive carbon black. ICPs form very large, extremely dispersion-resistant aggregates, and we therefore started by dispersing them at low concentrations. 

As discussed in Chapter 10, a wide variety of additives is used in the polymer industry. Stabilizers, waxes, and processing aids reduce degradation of the polymer during processing and use. Dyes and pigments provide the many hues that we observe in synthetic fabrics and molded articles, such as household containers and toys. Functional additives, such as glass fibers, carbon black, and metakaolins can improve dimensional stability, modulus, conductivity, or electrical resistivity of the polymer. Fillers can reduce the cost of the final part by replacing expensive resins with inexpensive materials such as wood flour and calcium carbonate. The additives chosen will depend on the properties desired. 

B - standard highly zlno pigmented paint modified by a conductive substitution of 1 % of zinc by carbon black. 

In addition to its role as a pigment, carbon black may be incorporated into polymers as a reinforcement for elastomers, as a UV stabiHser in polyolefins, or as an electrically conducting additive. In each case the physiochemical properties of the filler and its ultimate state of dispersion is critical in order to achieve... 

Besides rendering the conductivity of ABS, carbon black also works as a pigment and can also help reduce photo-oxidation (60). 

Densification by outgassing, a process by which the carbon black is conducted over porous, evacuated drums, is the weakest form of compacting which allows the carbon black to retain its powdery state [4.18], This form of compacting is used for certain pigment blacks which must remain very dispersible. 

Besides their two main uses as reinforcing fillers and pigments, small amounts of carbon blacks are used by the electrical industry to manufacture dry cells, electrodes, and carbon brushes. Special blacks are used to give plastics antistatic or electrical conduction properties. Another application is the UV stabilization of polyolefins [4.31]. 

Other important properties of Cr02 when used as a magnetic pigment are its black color, electrical conductivity (2.5-400 O-1 cm-1 [5.27]) and relatively high crystal hardness (Mohs hardness 8-9 [5.20]). Therefore, coating formulations based on Cr02 require less or even no additives such as carbon black (good conductivity, black color) or refractory oxides such as alumina. 

The most commonly used black pigments are carbon blacks. In addition to being efficient light absorbers, some varieties of these small-particle-size materials impart electrical conductivity and thixotropy to paints. The... 

The aim of this chapter is to provide an understanding of how carbon black particle size and shape translate into dispersion quality and other performance attributes in plastics applications. While this chapter focuses on carbon black s effectiveness as a pigment, some attention will also be paid to some of the other plastics performance properties it influences, such as stability against UV radiation, effects on mechanical properties, and electrical conductivity. At its conclusion, this chapter will help the reader select an appropriate carbon black grade for specific plastics applications. 

To improve the properties of the raw polymer (wear resistance, creep resistance, thermal and electrical conductivity), various fillers, such as glass fibers, powdered metals, and graphite, are combined with all three types of PTFE polymers, mostly by intimate mixing. Filled fine powders are produced mostly by adding fillers into a dispersion and then coagulating the mixture. Aqueous dispersions can also be modified by the addition of certain fillers, pigments, heat resistant dyes, carbon blacks, and powdered metals, especially when processed into films (see Chapter 6). 

The final pigment black concentration to produce a good opacity is 2-5%, for base coats up to 10%, calculated on resin solid. Pigment blacks with extremely high-structure and surface area can be used for electro-conductive coatings [4.27, 4.29]. The carbon black content in this case is 30-50% on resin solid. 

Continuous rotary Convection Direct/indirect Direct Indirect Conduction Crystals, coarse powders, extrudes, preformed cake lumps, granular paste and fillers, cakes back-mixed with dry product Chemical ores, food products, clays, pigments, chemicals Carbon black... 

Carbon black Electrical conductivity, pigmentation, reinforcement, thermal conductivity, thermal resistance... 

These data coming from different sources indicate a growing concern that UV stabilizers, which are expensive additives, may not per-foim up to expectations. Table 13.2 shows the amounts of various stabilizers absorbed on carbon black. The absorbed quantities are substantial to raise further questions regarding the effect of this absorption on the performance of stabilizers, considering that carbon black is present in many formulations either as filler or pigment. Table 13.3 shows that carbon black is not the only filler which absorbs UV stabilizers. Fillers used in this experiment, conducted in a cyclohexane suspension, were at low concentrations. The concentration of HALS was typical of many formulations. Results show that tertiary HALS is superior to secondary... 

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