Pigmentation black

COLORANTS FORFOOD,DRUGS,COSTffiTICS AND TffiDICALDEVICES] (Vol 6) Cl Pigment Black 1 [13007-86-8]... 

The characteristics of roUer process impingement blacks are basically similar to those of channel blacks. They have an acidic pH, a volatile content of about 5%, surface area of about 100 m /g, and an average particle diameter of 10—30 nm. The smaller particle size grades are used as color (pigment) blacks, and the 30-nm grade is used in mbber. 

Generally, the phenotype that predisposes an individual to an increased risk of skin cancer is red or blond hair, blue eyes, and fair skin. These characteristics are surrogate measure of the sensitivity of the skin to sun exposure and the tendency to develop nevi, freckles, and sunburns based on the skin type. Freckles, which may appear abruptly after the first high dose of UV radiation sun exposure, represent clones of mutated melanocytes, and their presence is associated with an increased risk of melanoma.12 The Fitzpatrick classification of skin type is used to determine the response pattern of the skin to UV radiation and assess the risk for melanoma. There are six Fitzpatrick skin types Type I skin always burns and never tans, type II skin burns easily and tans rarely, type III skin burns sometimes and tans usually, type IV skin burns rarely and always tans, type V skin always tans and is moderately pigmented (brown), and type VI skin always tans and is darkly pigmented (black). Fitzpatrick I and II skin types are commonly affected by NMSC and MM. The susceptibility to skin cancer, both NMSC and MM, is related to the melanin content of the skin and the skin s response to UV radiation. 

Pigment Blacks for Plastics, Degussa Technical Bulletin No. 40, Frankfurt am Main (1998). 

Aniline black (Cl Oxidation Base 1) is a complex polymeric phenazine that can be produced on cotton fabric by impregnation with aniline hydrochloride and suitable inorganic oxidants, such as sodium chlorate, ammonium vanadate and copper hexacyanoferrate(II). Aniline black is also made directly for use as a pigment (Cl Pigment Black 1). 

Some other pigments of this class are found on the market. In full shade, these pigments provide tones of black or very dark olive or violet hues, which satisfy certain spectral requirements in the IR region. Examples are Pigment Black 31,71132 and 32, 71133. Their properties include resistance to certain chemicals and good weatherfastness. 

Chemical class White pigments Black pigments... 

Spinel black Cu(Cr,Mn)204 Cu(Fe,Cr)204 [68186-91-4] [55353-02-1] Pigment Black 28 77428 Pigment Black 22 77429 black spinel intermediate between normal and inverse spinel... 

Figure 42. Color coordinates of black gravure inks with different toning + 2-4 Pigment Black LCF /Vossen-Blau 705 5-7 Pigment Black LCF/[VB 705-Pigment Red 57 1 (4 1)] x 1-10 Pigment Black LCF /[VB 705 Pigment Violet 27 (2 1)] 1 Pigment Black...

Figure. 43. Color locations of black offset printing inks with different toning 14 Pigment Black LCF...

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. 

Other pigment blacks and the rubber blacks are compacted by granulation. Two processes are used dry and wet pelletization. Dry pelletization is a simple, energysaving method, but it does not work with all types of carbon black. It is mainly used for color blacks. Dry pelletization is carried out in rotating drums, where the powdery carbon black rolls to form small spheres. 

In Germany, where natural gas was not available in sufficient amounts, the gas black process was developed in the 1930s. It is similar to the channel black process, but uses coal tar oils instead of natural gas. Yields and production rates are much higher with oil-based feedstock this process is still used to manufacture high-quality pigment blacks with properties comparable to those of channel blacks. The gas black process has been used by Degussa on an industrial scale since 1935. 

The mean primary particle sizes of pigment blacks he in the range 10-100 nm specific surface areas are between 20 and 1000 m2/g. The specific surface area, determined by N2 adsorption and evaluation by the BET method [4.29], is often cited as a measure of the fineness of a black. Blacks with specific surface areas >150 m2/g are generally porous. The BET total specific surface area is larger than the geometric surface area measured in the electron microscope, the difference being due to the pore area resp. the pore volume. 

With a consumption of about 150 000 t/a carbon blacks are the most important pigments used in the printing-ink industry. The required properties of the pigment black vary rather widely, depending on the printing process and the type of binder. 

A highly concentrated dispersion of carbon black is first prepared with a portion of the binder and solvent. The viscosity of this concentrate is a function of the particle size, structure, and surface chemistry of the black, the type of binder and its interaction with the pigment black, and the proportions of black, binder, and solvent. The final paint is made from the concentrate by adding more binder and solvent, its carbon black concentration is 3-8% referred to the solids content. Wetting agents are sometimes added to improve dispersibility and prevent flocculation. A number of concentrates for paint manufacture e.g., carbon black-nitrocellulose chips or carbon black -alkyd resin pastes, can be obtained from paint producers. 

The carbon black plastic concentrates are often not prepared by the plastics processor. They may be purchased, from the pigment-black manufacturer in the form of chips, pellets, or powders. Black-plasticizer pastes (e.g., black/DOP pastes for tinting plastisols) and water- and solvent-based dispersions (e.g., for fiber manufacture) are also commercially available. 

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