Jetness, carbon black pigments

Carbon black pigments are classified into six classes lamp black, furnace black, thermal black, acetylene black, channel black and gas black. They all differ in their typical properties such as particle size, jetness, undertone and surface chemistry. 

Generally, there are two basic types of inks. The first type contains finely dispersed carbon black or colored pigments in both solvent and water based systems. Pronounced improvements have been achieved in stabilizing aqueous pigment formulations for ink-jet applications by adding specific polymeric dispersing agents [18], The second type of ink is based on water or solvent soluble dyes. 

In addition to jetness, plastics pigmented with carbon blacks typically exhibit color undertones. Undertone in black plastics appears as a distinct blue or brown-to-orange undertone, depending on the particle size of the carbon black used. In general, in full-shade, black molded applications, fine-particle-size carbon blacks impart a bluer tone. This behavior reverses itself in tints. Large-particle-size carbon blacks impart bluer undertone. Note that the effects of fillers, polymers, and dispersion can alter the typical behavior described above. Tint strength is the relative ability of the carbon black to darken a resin colored with chromatic pigments. 

As a rule, low-structure carbon blacks impart greater jetness, but tint structure affects color to a lesser degree than primary particle size. Finally, agglomerates are undispersed clusters of aggregates that are physically bound together. The object of dispersion is to reduce agglomerate size and maximize pigment color development (Fig. 11.3)... 

We now consider the interface between carrier and toner, as these components interact in a dynamic development system. As we have noted, toner is commonly fabricated by "jet impacting" a brittle pigmented thermoplastic to form irregularly shaped particles of about 12/u m cross-section--particles whose surface comprises resin and carbon black (2, J 3, 58). The carrier cores are magnetic (ferrite or steel), typically about 250/4 m in size and therefore relatively massive. They are generally coated with a dielectric oxide or resin, which participates in the tribo-electrification process (2, it , 59). ... 

Chem. Desaip. Channel-type carbon black CAS 1333-864 EINECS/ELINCS 215-609-9 Uses Rller, pigment for top quality bik. PP, ABS, PA, PVC, painis/coat-ings, automotive finishes, metal decoration enamels Features High jetness black... 

The two most popular blacks used consist of imely divided forms of carbon known as carbon black and lampblack. Carbon black, the most widely used of the blacks, is sometimes called furnace black. It is made by the incomplete combustion of oil injected into the combustion zone of a furnace. Lampblack, or channel black, is made by the impingement of gas on the channel irons of burner houses. Both types of black come in a variety of pigment sizes and jetness and offer tremendous opacity Only 2-4 oz/gal(15-30 kg/m ) of paint are necessary in most instances for proper coverage.Even the most expensive, darkest jet blacks are inexpensive to use because only a small amount is needed. They also have excellent durability, resistance to all types of chemicals, and lightfastness. 

The purest white pigment is titanium dioxide and the most jet black, carbon (usually considered inorganic). There are no organic blacks and whites. 

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