Showing papers on "Precipitated silica published in 1988"

Hydrophobic precipitated silica granules

Abstract: Hydrophobic, essentially spheroidal precipitated silica particulates, well adapted as a reinforcing filler material for silicone elastomers, have a density of at least 0.15, a water wettability of at least 20% and a maximum water uptake of 5%.

Gas recombinant separator

Abstract: Described is a porous flexible sheet of about 96.5 to 99.5 weight percent amorphous precipitated silica and from about 0.5 to about 3.5 weight percent fibrillated, unsintered polymer, e.g., polytetrafluoroethylene. The sheet is useful as a separator in absorbed electrolyte gas recombinant batteries, e.g., lead-acid batteries. The sheet is prepared by subjecting a dry mixture of the silica and polymeric material, e.g., polytetrafluoroethylene, in the above proportions to mechanical shear blending forces to fibrillate the polymer and thereafter dry forming the resulting admixture into sheet form.

Fire-resistant composition

Abstract: A plastic composition which at least when hardened is resistant to fire comprises: a binder comprising a flexible film-forming adhesive polymer, such as polyvinylbutyral, in a volatile solvent, preferably a non-flammable volatile solvent such as trichloroethane, the binder having dispersed therein a fire retardant such as aluminium trihydrate, an exfoliatable mineral, such as vermiculite, and preferably also a thixotropic agent such as precipitated silica.

Corrosion inhibiting pigment

Abstract: Corrosion inhibiting calcium-containing amorphous precipitated silica is described. The silica is prepared by admixing simultaneously in a reactor aqueous alkali metal silicate, e.g., sodium silicate, acidifying agent, e.g., hydrochloric acid, and a water-soluble source of calcium, e.g., calcium chloride. The product contains from 6 to 9 weight percent calcium (as CaO). The silica product may be incorporated into a coating composition used for corrodible metallic surfaces.

Microcapsules and methods for their preparation

Abstract: Dump release microcapsules are formed of a water-reswellable gel having dispersed therein a sorbtive filler material having a median particle size of not more than 1 micron, such as fumed or precipitated silica. The filler material has an active substance absorbed therein and/or adsorbed thereon. The active material can be 2-chloro-6-(trichloromethyl) pyridine and the gel formed from crosslinked lignin or a lignosulphonate.

Precipitated silicas with a low water absorption, process for their preparation and their use to reinforce silicon elastomers

Abstract: The process for the preparation of these silicas is characterised in that a first precipitated silica is subjected to a heat treatment at a temperature of at least 700 DEG C for a period of at least one minute. The silicas obtained are particularly suited for use as reinforcing fillers in silicones.

Image analysis of fractal aggregates of precipitated silica

Abstract: Amorphous silica usually appears as a set of more or less spherical particles of a few hundred angstroms in diameter, building up extended aggregates. To understand how the shape of the aggregates observed by electron microscopy is related to the synthesis process, we have simulated by DLA and CCA models the way in which the elementary particles connect to each other. We study in particular how two-dimensional images inform us of the actual three-dimensional structure of the fractal aggregates. Results demonstrate the possibility of describing the morphology of precipitated silica using these models. A better understanding and a better control of the aggregation step seems possible by using these methods.

Polyolefin resin composition

Abstract: PURPOSE: To obtain a resin composition which can give a molding improved in mechanical strengths, impact resistance and tensile strength without causing hazing by adding a silicic filler surface-treated with a specified alkyltrialkoxysilane to a polyolefin resin. CONSTITUTION: The title resin composition contains a silicic filler surface-treated with an alkyltrialkoxysilane of the formula (wherein R is a 4-18C alkyl, and X is a 1-4C alkoxy). The silicic filler has an action of improving the rigidity and heat resistance of a polyolefin. Examples of the silicic fillers include talc, clay, mica, feldspar powder, fumed silica, precipitated silica, burned precipitated silica, burned diatomaceous earth and fine quartz powder. To surface-treat the silicic filler with the alkyltrialkoxysilane, the silane is uniformly attached to the silicic filler by adhesion or adsorption at 0-200°C and heat-treated at 40-300°C. COPYRIGHT: (C)1989,JPO&Japio

Curing of organopolysiloxane composition

Abstract: PURPOSE:To accomplish the titled curing using no curing catalyst, by heating under pressure, a composition comprising an alkenyl group-contg organo polysiloxane, organohydrogenpolysiloxane and finely powdered silica CONSTITUTION:The objective curing can be accomplished by heating under pressure, to >=150 degC (pref to >=180 degC), a composition comprising (a) 100ptswt of an organopolysiloxane having in one molecule at least two lower alkenyl groups, of formula (R is monovalent hydrocarbon group, 50mol% of which normally being methyl; a is 08-22 on average pref 195-205), (B) such an amount (normally 1-10ptswt) of an organo-hydrogenpolysiloxane having in one molecule at least tow hydrogen atoms bonded to the silicon atom as to be >=1mol of said hydrogen per mole of the alkenyl group in the component A, and (C) 5-200ptswt of finely powdered silica (pref precipitated silica prepared by wet process)

Thermoplastic cellulose derivative resin composition

Abstract: PURPOSE:To make it possible to form a thermoplastic resin composition good in dispersibility and moldability and high in heat resistance, surface hardness, rigidity, etc., by mixing a thermoplastic cellulose derivative resin with silica of specified properties. CONSTITUTION:This thermoplastic cellulose derivative resin composition is formed by mixing 100pts.wt. thermoplastic cellulose derivative resin with 10-40 pts.wt. silica having 3.0 or below silanol groups per 100 square Angstrom and a BET specific surface area of 100-210m /g. Although examples of said cellulose derivatives include cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate and nitrocellulose, cellulose acetate is desirable. Examples of said silica include one produced by heating precipitated silica obtained by, for example, a wet process, etc.

Hydrophobic precipitated silica, process for its preparation and its use to reinforce silicone elastomers

Abstract: This silica is characterised by a density of at least 0.15, a wettability with water of at least 20 %, a water uptake of not more than 5 % and by its presentation in bead form.