Carbon black is a crucially important component of most rubber compounds and is usually the largest volume ingredient after the polymer itself. Carbon black will affect many aspects of a rubber compound as well as many aspects of the mixing cycle. Due to the importance of carbon black to a rubber compound and potential for high filler loading, recognizing the total quality cost of using a particular grade of carbon black in the compound is essential.1 To assess the total quality cost of a carbon black in any given compound,aspects such as cost per unit weight of the filler, handling time and labour, mixing time and energy consumption, factory scrap rates for both mixing and final product, processability and final product performance, must be examined.
Although the term carbon black is often used in a generic sense, there are five main types; acetylene black, channel black, lamp black, furnace black and thermal black. The focus of this paper will be on thermal black N990/N991. The effects of using thermal black N990/N991 in a nitrile rubber compound for both compound properties and total quality cost will be demonstrated.
Thermal carbon black N990 is manufactured by the thermal decomposition of natural gas. This process produces a very unique carbon black characterized by a large particle size while having low structure. This paper will provide a general description of the thermal carbon black and the effects of this carbon’s unique properties on nitrile elastomers compounds. Advantages of using, medium thermal carbon black, including high loadability, low compression set, low compound viscosity and the potential for compound cost savings, will be discussed. A study conducted on behalf of Cancarb Limited., by the Indian Rubber Manufacturers Research Association, will be presented.
Although furnace carbon black comprises most of the world’s carbon black consumption, thermal carbon black plays a very significant role especially in compounds utilizing high performance polymers. Carbon black can be generally defined as very fine particulate aggregates of carbon with an amorphous quasi-graphitic molecular structure. Thermal carbon black is produced using a clean natural gas feedstock in a thermal decomposition reaction to produce a high purity carbon black with large particle size and low structure.