Showing papers on "Precipitated silica published in 1986"

Insulation formed of precipitated silica and fly ash

Abstract: Precipitated silica is mixed with a fly ash material and is employed as an insulating material having a low thermal conductivity. The mixture of precipitated silica and fly ash material is dried, compressed, placed in an evacuable pouch, and evacuated. The resulting board-like insulation configuration is used directly as insulation. The board-like material which is produced may be used as insulation in household refrigerators and freezers by placing it in an insulation space between the inner liner and the outer case and encapsulating the board-like material with a foamed insulating material.

Preparation of amorphous, precipitated silica and siliceous filler-reinforced microporous polymeric separator

Abstract: Precipitated amorphous silica useful for manufacturing microporous battery separators is prepared by establishing an aqueous solution of alkali metal silicate having an alkali metal oxide concentration of (a) from 21-26 grams per liter and a temperature of from about 179° F to 186° F, or (b) from 56 to 72 grams per liter and a temperature of from 190° to 198° F; adding from (a) 145 to 19 times or (b) 2 to 5 times respectively the amount of alkali metal silicate initially present in the initial aqueous solution simultaneously with acidifying agent, eg, sulfuric acid, to the initial aqueous solution while maintaining the initial alkali metal oxide concentration therein substantially constant; reducing the pH of the resulting slurry to from 8 to 9; ageing the slurry at precipitation temperatures for from 15 to 90 minutes; reducing the pH of the aged slurry to from 38 to 47 and then recovering, eg, separating, the silica from its entraining slurry, washing the recovered silica, and drying the washed precipitated silica Optionally, the recovered and dried silica is milled after drying to produce a product having a median agglomerate particle size of from 6 to 15 micrometers

Wrinkle treatment formulation

Abstract: A wrinkle treatment formulation is provided which is in the form of a gel formed of at least 95% by weight of a gelable hydrophilic polyurethane polymer base and a precipitated silica thickener gelling agent. Upon brushing the above-described gel formulation on wrinkled skin, the gel fills up wrinkles and dries to impart to so-treated skin a smooth substantially wrinkle-free appearance.

Precipitated silica carrier for vitamins

Abstract: Free flowing, substantially dust-free, dense granular amorphous precipitated silica having a principal particle size of between about 0.14 millimeters and about 0.84 millimeters are described. This material is particularly suitable as an inert carrier for water-soluble and fat soluble nutritional supplements, e.g., vitamins, which are added to feeds for livestock.

Thermal insulating slabs for freezers and refrigerators comprising an envelope filled with precipitated silica which is subsequently compressed and the process for their manufacture

Abstract: Precipitated silica, formed by the interaction of sodium water glass and sulfuric acid, followed by mechanical processing, is employed as an insulating material having a low thermal conductivity. The precipitated silica is dried, compressed, placed in an evacuable pouch, and evacuated. The resulting board-like insulation configuration is used directiy as insuiation in, for example, household refrigerators.

Process and low sodium catalyst for the production of formaldehyde from methane

Abstract: Formaldehyde is made from methane (such as from natural gas) and a molecular oxygen containing gas by using a silica supported catalyst having less than 350 parts per million by weight of sodium and having a catalytically effective amount of MoO3. The low sodium form of the silica support can be made by washing silica gel or precipitated silica, by using a fumed silica or by making an ultrapure form of silica having a silica purity of at least 99.99% silica. The ultrapure form can be made by the hydrolysis of silicon tetraalkoxides. In general, the lower the sodium level, the better is the catalyst.

A method of reinforcing elastomers with silica

Abstract: The filler comprises at least one precipitated silica with the following characteristics:… - a CTAB surface area of between 20 and 200 m /g,… a mean aggregate projected area greater than 10,000 nm ,… - a high interaggregate volume of at least 1 cm /g and a homogeneous interaggregate pore population.

Process for the production of a seed mixture for the synthesis of faujasite

Abstract: Precipitated silica is mixed with a solution of caustic soda, water and sodium aluminate to form a mixture of the composition: 12±3 Na2 O:Al2 O3 :12±3 SiO2 :200±60 H2 O. This mixture was aged for 18-72 hours.

Process for packaging food to be cookedby a yarn made of silicone elastomer

Abstract: 1. Process for wrapping an alimentary product to be cooked, according to which the product is wrapped by a ligature, characterized in that the constituent material of the ligature is a silicone elastomer originating from the hot vulcanization of an organopolysiloxane composition comprising at least one diorganopolysiloxane resin in which the organic radicals are chosen from methyl and vinyl radicals and, if desired, phenyl and 3,3,3-trifluoropropyl radicals, a pyrogenic silica and/or a precipitated silica and a crosslinking system chosen from an organic peroxide and the combination of a hydromethylpolysiloxane and of a catalytically effective quantity of a catalyst of the platinum group.

Rubber vibration insulator composition

Abstract: PURPOSE:To obtain a rubber vibration insulator compsn which exhibits a consistent vibration insulation effect over a wide temperature range, by blending fine silica powder and an organopolysiloxane with a synthetic rubber CONSTITUTION:A rubber compsn consists of 100ptswt synthetic rubber (A), 10-100ptswt fine silica powder (B) having a specific surface area of 50m /g and 3-20ptswt organopolysiloxane (C) of formula I (wherein R -R are each a monovalent hydrocarbon group and at least one of R -R is phenyl or a 2-10C alkyl; m is 1-20; n is 0-20) As said synthetic rubber, an organopolysiloxane rubber having a viscosity of 1,000cS or above at 25 degC and formula II (wherein R is a monovalent hydrocarbon group, at least 50% of which is a methyl group; n is 199-202) is preferred, since its mechanical properties are less temperature- dependent Examples of fine silica powder are fumed silica and precipitated silica

Effect of precipitated silica on plate-out of poly(vinyl chloride) compounds

Abstract: Plate-out is the undesired deposition of materials from a compound onto the surface of processing equipment. Plate-out causes problems with quality control and down-time. Changes in processing conditions can help alleviate plate-out, but adjustments in the formulation are usually needed for significant improvements in plate-out, the deposition. The addition of precipitated silica to a PVC formulation is a simple and effective method to reduce plate-out. This study explores the relationship between plate-out reduction and the physical properties of precipitated silica. Silica properties such as surface area, average particle size, and oil absorption can all be controlled by a patented process developed by the Chemicals Division of J. M. Huber Corporation. Plate-out reduction is related to the properties of precipitated silica, the loading of the silica, the order of addition, and type of PVC formulation. The effect of precipitated silica on the physical properties of the PVC compound, such as, tensile strength, tear strength, elongation and stiffness, are explored. Finally, the effectiveness of plate-out reduction by precipitated silica as compared to fumed silica will be discussed.

Process for the preparation of precipitated silica

Abstract: Crystalline precipitated silica is produced by hydrolyzing silicon tetrachloride in the presence of fluoride ions at a temperature of up to 60° C.