Welan gum in cement compositions

• US 4,963,668 A
• Filed: 06/14/1989
• Issued: 10/16/1990
• Est. Priority Date: 05/07/1987
• Status: Expired due to Term

• Current Assignee: Cp Kelco (JM Huber Corporation)
• Original Assignee: Merck & Co., Inc.
• Inventors: Lindroth, Thomas A., Best, Glen H., Allen, Floyd L.
• Primary Examiner(s): Griffin, Ronald W.
• Assistant Examiner(s): White, Everett
• Application Number:
  US07/366,063
• Time in Patent Office: 489 Days
• Field of Search: 536/114, 536/124, 536/119, 435/252.1, 435/829
• US Class Current: 536/114
• CPC Class Codes: C04B 24/38 Polysaccharides or derivatives thereof C04B24/243 takes precedence
• CPC Class Codes: C12P 19/04 Polysaccharides, i.e. compounds containing more than five saccharide radicals attached to each other by glycosidic bonds
• CPC Class Codes: Y10S 435/829 Alcaligenes

Abstract

Low viscosity welan gum having a 5% (wt.) aqueous solution viscosity of 100 cP and process for preparation of such are described.

Claims

1. A low viscosity welan gum having a 5% (wt.) aqueous solution viscosity of 100 cP as measured on a Brookfield LVT viscometer, at 25°

C., spindle 2, 60 rpm.

2. A process for preparing a heteropolysaccharide of claim 1 which comprises degrading a welan gum solution by heating such at 48°

to 83°

C. for a sufficient amount of time in the presence of 0.05 to 0.25% ethylenedinitrilo tetraacetic acid tetrasodium salt, 0.01 to 0.1% ferrous sulfate, and 2-6% hydrogen peroxide, based on the weight of heteropolysaccharide.