1,956,053, Issued April 24, 1934, in which a watery slurry go of asbestos is treated with an aqueous dispersion of electropositive rubber particles which dispersion may be acid in reaction or may contain polyvalent metal ions.Īn object of this invention is to provide a suspension of carbon black in,water in which the carbon black is more completely dispersed and which therefore possesses greater tinctorial power than has heretofore been possible. Similarly, 2g dispersions of carbon black in water prepared with the aid of soaps or proteins are also especially ineffective for use in connection with the general process described in my Patent No. The latter disadvantages render soaps or proteins particularly ineffective to disperse carbon black in water for use in cement or mortar or in paper-making when an acid or alum size is employed or for use with aqueous slurries of as- D bestos such as are commonly encountered in the manufacture of asbestos board, gasket material, and the like, which slurries, owing to the inherent chemical nature of the asbestos, always contain calcium and magnesium ions. In order to be effective they must be used in relatively large quantities and, furthermore, they lose their effectiveness and are precipitated when brought in contact with acid environments or the ions of heavy metal salts. Furthermore, soaps and proteins are in themselves attended with certain disadvantages. This is believed to be due 0 to the fact that carbon black particles are very much smaller than, in fact of a different order of magnitude from that of, the particles of ordinary pigments. While these agents are generally very effective to disperse most finely divided pigments in water, carbon black presents unusual difficulties and is not particularly well dispersed by them. For this purpose there have been employed soaps, such as sodium stearate or oleate, and proteins, such as casein, hemoglobin, or albumen. These non-wetting and non-dispersing characteristics constitute serious disadvantages in the practical use of carbon black when suspended in water because carbon black is generally used 15 for its tinctorial power and, as is well known and recognized, the tinctorial power of a finely divided material is proportional to the size of the individual particles and the completeness with which they are dispersed.Īttempts have been made to overcome the stated difficulties by adding certain protective colloids to the water in which the carbon black was to be suspended. agglomerate, and do not disperse in the aqueous medium 10 as colloidal particles of carbon black. If carbon black is stirred into water, it will be found that the particles are not readily wet by the water and, once wetted, they tend to cling together, i. The dispersion of carbon black in water presents difficulties, however, and these difficulties have militated against its more general and otherwise advantageous use. Furthermore, it has been proposed, and the process presents much promise, to use a dispersion of carbon black in an aqueous medium as a printing ink in place of the printing inks ordinarily used consisting of carbon black and a suitable oil. Black concrete or cement is commonly prepared by mixing carbon black with the cement or mortar when in the wet state. Aqueous dispersions of carbon black are frequently added to rubber latex to provide a compounding and pigmenting agent for the rubber constituent thereof. In this manner carbon black is commonly added to aqueous slurries of asbestos which are to be used for the manufacture of asbestos board, gasket materials, and the like. Thus, for example, it is frequently used as a pigment in the preparation of black paper or paper-like materials in which case the carbon black may be slurried in water and added as a paste or thin slurry to the stock in a paper beater. There are many industrial applications of carbon black which require its suspension or dispersion in an aqueous medium. This invention relates to the dispersion of carbon black in an aqueous medium, and generally comprises the use of a dispersing agent of the general structure obtained by condensing a naphthalene sulfonic acid, or a homoloque or derivative thereof, with formaldehyde, or its equivalent, a process and a produce thereof, all as here'inafter more fully described and claimed.
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