Pharmacia Corporation

Merck + Co., Inc.

Cp Kelco U.s., Inc.

Bryan Skaggs

Walter Gregory Rakitsky

Harold Dean Dial

John M Swazey

James M Seheult

Alain Phyfferoen

Mike O'Brien

The present invention comprises a stable hydrocolloid composition in which preferably welan gum is uniformly dispersed in a superplasticizer solution such as sulfonated naphthalene, sulfonated melamine, modified lignosulfate, their derivatives and mixtures thereof. The solution is wet milled to form an extremely fine particle size distribution of the gum. The composition is rapidly hydratable and useful as a stabilizing additive in many cement and drilling fluid applications.

Stable suspension of hydrocolloids and superplasticizer

In accordance with the present invention, a microbial polysaccharide having the features characteristic of S-657 has been found to be effective to improve the rheological properties of a variety of cementitious systems. Thus, the addition of a small, but effective amount of S-657 to such cementitious systems as portland cement, self-leveling grouts, fresh or saltwater oil well cement slurries, microfine cements, and the like, gives rise to substantial improvements in such properties as bleed, flow resistance, fluid loss control, and the like. S-657 addition provides enhanced rheological control in a variety of cementitious systems. In addition, S-657 provides a number of advantages relative to prior art systems, including improved free water and sedimentation control, as well as reduced fines loss during underwater placement. This unique biogum has been shown to enhance the stability of highly diluted microfine cementitious systems, and enhance the flow and workability of superworkable and self-leveling pastes. The homogenous set cement resulting from the introduction of S-657 into cementitious systems promotes bond strength and eliminates the need for vibrated concrete. Efficient free or bleed water control eliminates unsightly vugs or voids adjacent to the form work and thus enhances the appearance of the finished concrete. This highly efficient polymer provides additional benefits as well, such as, for example, enhanced color delivery in pigmented concrete and stabilized bubble entrapment in so called foamed or cellular cement systems. When used in sprayable cementitious systems, S-657 reduces rebound and sag.

Methods for improved rheological control in cementitious systems

The present invention comprises a stable hydrocolloid composition in which preferably welan gum is uniformly dispersed in a superplasticizer solution such as sulfonated naphthalene, sulfonated melamine, modified lignosulfate, their derivatives and solution thereof. The mixture is wet milled to form an extremely fine particle size, from about 3 microns to about 500 microns distribution of the gum. The composition is rapidly hydratable and useful as a stabilizing additive in many cement and drilling fluid applications.

A liquid carrier fluid that is used as a carrier system to suspend and deliver water soluble polymers which act to adjust the rheological properties of the aqueous systems to which they are added.

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San Diego, CA, United States of America

Bryan Skaggs