Modifying the surface chemistry of carbon materials has been a goal of chemists for many decades. While it was possible to physically adsorb chemicals onto the surface of a carbon material, permanently changing its surface chemistry in a controlled manner was substantially more difficult.

In 1993, Cabot researcher Jim Belmont and his team invented a process for modifying carbon's surface with specific functionalities. The process involved the reaction of a diazonium salt with a carbon material without an externally applied current to reduce the diazonium salt. In this process the diazonium salt is formed in situ and the carbon product is isolated and dried by typical means. The process was carried out under a variety of reaction conditions and in various types of reaction media, including both protic and aprotic solvent systems or slurries.

With this critical breakthrough, Cabot chemists and researchers could prepare surface modified carbon black products with properties never before associated with carbon materials. Many industries have benefited from the profound changes that carbon black surface modification technology can provide, including those listed below.

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Inkjet Colorants:

The surface modification technology allows organic groups substituted with an ionic or an ionizable group as a functional group to be attached to carbon black particles. This functionality gives the particles increased water dispersibility.

Cabot's CAB-O-JET inkjet colorants (both carbon black-based and color-based pigments) are stabilized through the chemical attachment of groups to the pigment surface, resulting in a highly stable dispersion that delivers greater optical density and the sharper resolution demanded by consumers. Printer ink manufacturers and distributors favor our Inkjet Colorants for their exceptional purity, stability, long shelf life and reliable printing performance.

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Automotive Coatings

Thanks to surface modification technology, automotive coatings manufacturers now have pigments with faster dispersion rates, reduced milling times and lower surfactant requirements. Our Emperor grades of modified carbon black pigments for coatings allow manufacturers to achieve a more complete dispersion, yielding increased jetness and blue tone.

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Displays – Materials for Color Filters

The demand for bigger flat panel displays requires new manufacturing methods and new materials to reduce production costs. The new color filter architectures require that the black matrix have a balance of electrical and optical properties unobtainable from conventional materials. Through the use of unique attachment chemistries, Cabot has developed carbon blacks for black matrix that has a balanced performance and unique formulation flexibility.