| 摘要 |
A carbon black ink pigment may be prepared by contacting an ozone-containing gas stream with an oil furnace black which embodies the following characteristics within the indicated ranges: .E.M. surface area.120-150 m2 per gm .B.E.T. surface area.100-170 m2 per gm .Oil absorption.7-14 gal. per 100 lbs., the ratio of B.E.T. surface area to E.M. surface area of the black not exceeding 1.3 : 1, the furnace black so treated being in unpelleted form both before and throughout the entire ozonation, and the ratio of carbon black to ozone, by weight, not exceeding 25 : 1 and preferably above 10 : 1. The black used may have up to 10% by weight moisture content. The ozonation, which may be carried out at temperatures less than 300 DEG F., particularly 70-90 DEG F., is advantageously effected with a dry-air ozone mixture containing not more than 6% by weight of ozone and preferably 0.4-3%. Two alternative means of ozonation are disclosed and exemplified. In the first, continuous ozonation is effected by passing the black at a uniform rate through a slowly-rotating drum and passing an ozone-containing air stream through the drum in contact with the carbon black. For example, using a drum 10 feet in diameter, 30 feet in length which rotates at 1-2 r.p.m. the contact time between the gas stream and carbon black was one hour. Alternatively, the carbon black may be suspended in the gas stream prior to its introduction into the reaction vessel, e.g. two cyclone-type separators connected in series in which case the contact time is usually less than 1 minute. The product from either process, i.e. a carbon black characterized by a low structure, an E.M. surface area of from 120-150 m2 per gm., a B.E.T. surface area of from 100-170 m2 per gm., the ratio of the B.E.T. to E.M. surface area not exceeding 1.3 : 1, an oil absorption of 7-14 gallons per 100 lbs., and a volatile content in an amount of at least 2 x 10-4 grams of volatile matter per m2 of carbon black surface of which total at least 30% is carbon dioxide, is claimed per se. Specifications 715,713 and 763,159 are referred to. |
