Precipitated silica

About: Precipitated silica is a research topic. Over the lifetime, 1401 publications have been published within this topic receiving 20992 citations.

Composite of silica reacted with blocked mercaptoalkoxysilane and alkyl silane, rubber composition with said composite, and article having component thereof

Abstract: The invention relates to amorphous silica (e.g. silica aggregates) having hydroxyl groups (e.g. silanol groups) on its surface which has been pre-reacted (e.g. pre-hydrophobated) with a combination of blocked mercaptoalkoxysilane coupling agent and an alkyl silane to form a composite. The invention further relates to a rubber composition which contains such composite, particularly as reinforcement. The invention additionally relates to article of manufacture, such as for example a tire, having at least one component of such rubber composition. The blocked mercaptoalkoxysilane is composed of a mercaptosilane where the hydrogen moiety of the mercaptan moiety is substituted with a blocking moiety which allows the alkoxy groups of the mercaptoalkoxyosilane to react with a precipitated silica having hydroxyl groups (e.g. silanol groups) on its surface for the silica pre-treatment thereof yet renders the mercapto portion of the mercaptoalkoxysilane as being relative inert insofar as subsequent coupling reaction with the elastomers until the blocked mercapto portion of the mercaptoakoxysilane becomes unblocked. Further, generation and release of reaction byproducts (e.g. alcohols) caused by reaction of alkoxy groups of the mercaptoalkoxysilane and byproducts from reaction of alkoxy or halogen groups of the alkylsilane with the hydroxyl groups of the amorphous silica is basically relegated to the pretreatment (said pre-reaction) of the blocked mercaptoalkoxysilane and alkylsilane with the silica and thereby essentially dissociated from and consequently eliminated, or at least minimized, during the actual subsequent mixing with the elastomer(s). Upon subsequent unblocking of the blocked mercapto moiety of the mercaptoalkoxysilane of the pre-hydrophobated silica within the rubber composition during the subsequent vulcanization of the rubber composition at an elevated temperature, the silica becomes coupled via the mercapto group of the mercaptoalkoxysilane to one or more elastomers of the rubber composition.

Dispersible silica particulates

Abstract: Uniquely dispersible precipitated silica particulates, e.g., beads, powders and granulates/extrudates, very well suited for the reinforcement of elastomer/rubber matrices, e.g., tires for the automotive industry, have characteristic particle sizes, BET and CTAB specific surface areas, DOP oil absorption values, total pore volumes and pore size distributions, and reduced degree of attrition.

High solids aqueous silica slurry

Abstract: Described are high solids aqueous slurries of amorphous precipitated hydrated silica, which slurries are of relatively low viscosity. The slurry typically contains from about 40 to about 60 weight percent of hydrated precipitated high structure silica. The viscosity of the high solids slurry is less than about 1000 centipoises. Processes for producing the aqeuous high solids silica slurry are disclosed. In one embodiment, a wet cake of amorphous precipitated hydrated silica is liquified and the liquified wet cake charged to a high-intensity mill wherein the silica is wet milled until the median agglomerate particle size of the silica is between about 0.3 and about 3 microns. In a further embodiment, finely-divided dry amorphous precipitated silica is slurried in a dispersion mill to the desired solids level and this slurry charged to a high-intensity mill and wet milled therein until the aforesaid agglomerate particle size range is attained. The resulting high solids slurry can be shipped in bulk with only mild agitation to prevent settling. A dispersant may also be added to the slurry prior to milling to retard settling of the silica.