Abstract: Fine crystals characterized by improved morphological homogeneity and a narrow size distribution are prepared by introducing a solution of a crystallizable solute in a solvent into a bed of small inert continuously moving solid particles and initiating crystallization within the solution while it is in contact with the moving particles. The process finds application in the manufacture of diverse crystalline products such as, for example, in the formation of metal oxalates, phosphorescent compounds, and silver halide crystals, as well as in the purification of both organic and inorganic materials.

Abstract: Magnetic recording elements containing substantially transparent magnetic recording layers which exhibit excellent magnetic recording and reproducing characteristics. Such elements contain a support and a transparent magnetic recording layer. The recording layer has a thickness up to about 5 microns and contains acicular, magnetizable particles having an average width of less than about 0.06 micron and an average length up to about 1 micron. These particles are substantially homogeneously dispersed in a medium that comprises a binder and has a refractive index which is substantially the same throughout the thickness of the magnetic recording layer. The concentration of the binder is at least about 10 parts per 100 parts, by weight, of the particles and is up to about 30 parts, by weight, for particles having an average length of at least about 0.06 micron and up to about 40 parts, per 100 parts, by weight, for particles having an average length of less than about 0.06 micron.

Abstract: A process of preparing magnetic recording elements containing substantially transparent magnetic recording layer which exhibit excellent magnetic and reproducing characteristics is as follows:(a.) forming a substantially homogeneous dispersion of acicular magnetizable particles in a medium comprising a solution of substantially transparent binder in solvent using particles having an average width of less than about 0.06 micron and an average length up to about 1 micron; the concentration of the binder being at least about 10 parts per 100 parts, by weight, of the particles; up to about 30 parts, by weight, for particles having an average length of at least about 0.06 micron and up to about 40 parts, by weight, for particles having an average length of less than about 0.06 micron,(b.) coating a support with the dispersion in an amount sufficient to provide a final dry layer thickness up to about 5 microns,(c.) removing substantially all solvent from the layer and(d.

Abstract: Fine crystals characterized by improved morphological homogeneity and a narrow size distribution are prepared by introducing a solution of a crystallizable solute in a solvent into a bed of small inert continuously moving solid particles and initiating crystallization within the solution while it is in contact with the moving particles. The process finds application in the manufacture of diverse crystalline products such as, for example, in the formation of metal oxalates, phosphorescent compounds, and silver halide crystals, as well as in the purification of both organic and inorganic materials.

Abstract: A magnetic recording element having greatly improved resistance to wear and tear is disclosed. This element includes in a magnetizable layer a carbonic acid ester lubricant such as ethyl cetyl carbonate, ethyl lauryl carbonate, didodecyl carbonate or phenyl cetyl carbonate. The lubricant can be present in an amount between 1 and 40% by weight of the binder, and advantageously about 20%. A typical binder is a copolymer of vinyl chloride with vinyl acetate, with or without polyurethane.