摘要:
The invention relates to matted UV varnishes comprising silicon dioxide, the surface thereof having been modified by means of treatment with a multiple bond organopolysiloxane so as to be particularly well-suited for use as a matting material for UV varnishes, and to a method for producing same.
摘要:
The invention relates to a process for the preparation of a novel precipitated silica, wherein: a silicate is reacted with an acidifying agent, so as to obtain a silica suspension; said silica suspension is filtered, so as to obtain a filter cake; said filter cake is subjected to a liquefaction operation, optionally in the presence of an aluminium compound; wherein at least one polycarboxylic acid is added to the filter cake, during or after the liquefaction operation. It also relates to a novel precipitated silica and to its uses.
摘要:
The present invention relates to spherical beads comprising at least one metal and/or semimetal oxide, having a mean diameter in the range from 10 to 120 μm, a BET surface area in the range from 400 to 800 m2/g and a pore volume in the range from 0.3 to 3.0 cm3/g, wherein the diameter of a given bead at any one point of said bead deviates by less than 10% from the average diameter of said bead and the surface of said bead is substantially smooth, and also to a process for producing these spherical beads, to a particulate catalyst comprising the spherical beads and to the use of the spherical beads as catalysts or catalyst carriers.
摘要:
A method for preparing precipitated silicas is described. A precipitation reaction between a silicate and an acidifying agent is also described, wherein a precipitated silica suspension is produced, and, subsequently, separation and drying of the suspension is conducted, in which, inter alia, one of the following three operations (a, b or c) is performed: (a) simultaneously adding a compound of aluminium and a basic agent, (b) simultaneously adding a silicate and a compound of aluminium, (c) simultaneously adding the acidifying agent, a silicate and a compound of aluminium.
摘要:
Dry, freely-flowing, water-insoluble but readily dispersible, solid and homogeneous silica pigment particulates essentially spheroidal in geometrical configuration and having a mean particle size in excess of 80.mu., preferably in excess of 150.mu., are prepared by atomizing to dryness a pulverulent aqueous suspension of silica having a solids contact in excess of 18%. Such silica pigment particulates, advantageously comprised of precipitated silica, are well adapted as reinforcing fillers for elastomeric matrices.
摘要:
In a method for manufacturing silica a leaching of natural silicates is performed with hydrochloric acid or other mineral acids, draining, drying and possibly a grinding up of the residue of the product obtained. In order to obtain a spherical silica with a controlled particle size and surface characteristics a mineral olivine with the highest possible degree of purity is employed as the basic material. This raw material is reduced to a grain size between 0.05 and 5 mm. The particles are pretreated and washed for the removal of dust on the grain surfaces and heavy materials such as spinel and at least a part of the foliar and stem-like minerals such as serpentine, talc and pyroxene are removed. The olivine particles are then leached in a controlled leaching process where the acid concentration, leaching temperature and leaching time are controlled in order to achieve the desired primary particle size, specific surface and pore volume measured according to the BET method on the extracted silica. The particle agglomerate of spherical particles thus formed with a grain size between 30 and 70 nanometers are washed and dried in the conventional manner, whereupon the agglomerate is divided into the spherical particles.
摘要:
Disclosed are amorphous silica or silica-alumina spherical particles composed of X-ray diffractometrically substantially amorphous silica or silica-alumina, wherein individual particles have a definite spherical shape and a notched surface, the circularity (A) represented by the following formula: ##EQU1## wherein r1 stands for the radius of the circumcircle of the profile of the particle in an electron microscope photo thereof and r2 stands for the radius of the inscribed circle of the profile of the particle in the electron microscope photo, is in the range of from 0.90 to 1, the notching degree (B) represented by the formula: ##EQU2## wherein .DELTA.t stands for the depth between the peak and trough in the radial direction of notches on the profile of the particle in the electron microscope photo and r1 is as defined above, is in the range of from 1 to 10%, and the primary particle size (2r1) determined by the electron microscope method is in the range of from 0.1 to 20 .mu.m.
摘要:
Stable aqueous suspensions of precipitated silica, well adopted as coatings for the papermaking industry, include an aqueous suspension of a slaked precipitated silica filter cake and an effective amount of a stabilizer therefor, which stabilizer contains (a) aluminum or an aluminum compound, and (b) an anionic dispersing agent.
摘要:
Elastomeric compositions contain crosslinked poly(diorganosiloxane) and reinforced precipitated silica having, on a coating-free and impregnant-free basis, a surface area of from about 220 to about 340 square meters per gram, a pore diameter at the maximum of the volume pore size distribution function of from about 9 to about 20 nanometers, and a total intruded volume of from about 2.6 to about 4.4 cubic centimeters per gram.
摘要:
The invention is a process for preparing amorphous silica alumina spherical particles by mixing sodium silicate or silicic acid gel with sodium aluminate and sodium hydroxide in an aqueous solution to form a gel, homogenizing the formed gel, crystallizing this intermediate product at 85.degree. C. to 200.degree. under atmospheric pressure or under hydrothermal conditions to form spherical zeolite particles with an x-ray diffraction pattern inherent to P-type zeolites and with a notched surface, treating the zeolite particles with acid to remove the sodium, thereby rendering the particles amorphous.