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US 5,175,277 AGranted
Rapidly hydrating welan gum
AssigneeMerck & Co., Inc.
InventorsWalter G. Rakitsky, Danny D. Richey
Life of this patent
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Abstract
A rapidly hydrating welan gum useful for preparing cementitious products. The gum can be dry blended with cement or other dry component and then added to a preformed cement/water pre-mix, thereby alleviating the need for hydrating the gum prior to addition to a cement/water mixture.
Claims1
A rapidly hydrating welan gum heteropolysaccharide prepared according to the process steps of:
- a) inoculating a suitable aqueous nutrient media with Alcaligenes bacterial strain ATCC 31555;
- b) aerobically fermenting the bacteria at a pH of between about 6.5 and 7.5;
- c) adding calcium propionate to the broth, adjusting the pH to about 10.5-12.5, and heating the fermentation broth at a temperature of about 170.degree. F.-230.degree. F. for about 3-20 minutes;
- d) precipitating the heteropolysaccharide from the fermentation media;
- e) drying the precipitate;
- and
- f) milling the dried precipitate.
4 more elements
Dependencies are inferred from the claim text.