Carbon blacks grades

Carbon black grades identified by four characters (ASTM D1765-67), ie, cure rate of normal (N) or slow (S), digit classifyiag typical particle size ia am, and two arbitrarily assigned characters. 

The consumption of the vanous carbon black grades can be divided into tread grades for tire reinforcement and nontread grades for nontread tire use and other mbber appHcations. Table 9 shows the distnbution of production of types for these uses. In the United States 55% production is for tread grades. In Western Europe tread-grade production is 64%, and in Japan it is 60%. 

For a deeper understanding of structure-property relationships it is useful to consider the effect of carbon black grade and concentration as well as polymer type on the dielectric properties more closely. In Fig. 29 the real part of the a.c.-conductivity o at 20 °C of a series of rubber composites, consisting of the more polar statistical co-polymer NBR and the fine black N220, is depicted for various filler concentrations in the high frequency regime up to 1 GHz. For the lower carbon black concentrations, a power law behavior with exponent around 0.6 is observed, while the highly filled com-... 

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. 

Three variables affect color performance of carbon black in plastics the particle size and shape or morphology of a carbon black grade, the polymer in which it is... 

Unlike diamond and graphite, which are crystalline carbons, carbon black is an amorphous carbon composed of fused particles called aggregates. Properties, such as surface area, structure, aggregate diameter and mass differentiate the various carbon black grades. 

Six types of carbon black are produced worldwide acetylene black, channel black, furnace black, gas black, lamp black and thermal black. Specific physical and chemical properties of a carbon black grade are summarized on its material safety data sheet and the suppliers product technical bulletin. 

FIGURE 31.2. SAXS-data for the carbon black grades N115, N121,andN339. 

Table 1 Natural rubber compounds with a range of carbon black grades ...

The carbon black critical loading factor and the optimum loading level tvill be a function of the specific carbon black grade and specific grade of polymers in the rubber compound blend, and are therefore unique for each polymer and filler system. 

Master batch butyl polymer, 100 phr GPP carbon black grade N660, 70 phr paraffinic oil, 25 phr zinc oxide, 5 phr. 

Carbon black grades NlOO Series NlOO Series NlOO Series... 

There are many additives employed in the plastics industry. Among the most versatile is carbon black. It is used to provide colour, opacity, protection from ultraviolet light, electrical properties, thermal conductivity, and even reinforcement. Advanced production methods have enabled carbon black suppliers to develop a wide range of carbon black grades that, in turn, provide plastics processors with additive selections geared to specific end-use properties. Selection of the proper carbon black is critical to successful end-use performance. Unlike some plastics additives, carbon black is not simply added to the mix. It must be dispersed into a resin system, and the quality of the dispersion is essential to performance. This chapter discusses the fundamentals of carbon black, its selection in plastics applications, and dispersion equipment and techniques. 

In addition to jetness, there are other important appearance considerations for plastics that can be controlled by the selection of an appropriate carbon black grade, such as undertone, tint strength and gloss. Undertone is a subtle, secondary colour underl)dng jetness. The undertone exhibited by carbon blacks can range from a warm brown to a cool blue. Tint strength is the relative ability of the carbon black to darken a coloured resin. Gloss level can range from a very shiny appearance to a matt finish. 

Achieving a good dispersion depends on selection of a carbon black grade that is as low as possible in surface area and as high as possible in structure. However, because the carbon black properties that produce the best dispersion frequently are not ideal for a given end use, it is necessary to determine a balance between dispersion qualities and end-use requirements. Other factors in a successful dispersion include the formulation and type of equipment to be used. 

There are a number of variables to consider in selecting the best carbon black grade for a given plastics application. Although each end-use may call for different carbon black characteristics, there is such a wide range of grades available that it is usually possible to identify one with the particular combination of properties needed. Careful consideration of the resin as well as accurate formulation and proper dispersion are also important in achieving desired end-use performance. 

Viscoelastic methods for the characterisation of gum rubbers are extended to rubber compounds, and the ways in which the viscoelastic properties of gum rubbers are manifested in the properties of the corresponding compounds are examined. The development of a method for evaluating strain amplification and strain rate amplification is described. Examples are presented of the characterisation of compounds with respect to variations in gum rubbers and carbon black grades, and consideration is given to the unique characteristics of compounds which are not observed in gum rubbers. Quality control tests for gum rubbers and compounds based on viscoelasticity are reviewed. 32 refs. 

Table 8.1 The Seven ASTM Series of Furnace Carbon Black Grades...

While there are 27 different grades of commercial carbon blacks listed in ASTM D1765, it is estimated that only half of the commercial carbon blacks are listed there. The other half are proprietary carbon blacks without ASTM N numbers. Some carbon black manufacturers prefer not to list some of their carbon black grades because they can maintain better commercial product differentiation with less risk of their special carbon black becoming a simple commodity carbon black with little chance of maintaining product differentiation. 

Pena, J.M., Allen, N.S., Edge, M., Liauw, C.M., Roberts, 1., Valange, B. Triplet quenching and antioxidant effect of several carbon black grades in the photodegradation of LDPE doped with benzophenone as a photosensitizer. Polym. Degrad. Stab. 70, 437-454 (2000)... 

In carbon, the conductivity varies from 10 (ohm-cm) for amorphous carbon to approximately 300 (ohm-cm) in the longitudinal direction for PAN-based high modulus carbon fibers. Apart from relatively low conductivity, carbon has the same magnetic permeability as aluminum, i.e., approximately 1. In order to obtain a given damping, carbon-based fillers have to be added in higher concentrations in comparison with metallic fillers such as steel. However, special carbon black grades with microporous structure and increased conductivity can now be found that allow the construction of a conductive network at relatively low concentrations. 

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