US4963668A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Welan gum in cement compositions
Assignee: CP Kelco US Inc
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Filing: 1989-06-14
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Granted: 1990-10-16
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Expires: 2009-06-14
Abstract
Abstract Low viscosity welan gum having a 5% (wt.) aqueous solution viscosity of 100 cP and process for preparation of such are described.
Inventors
- 👤 Floyd L. Allen
- 👤 Glen H. Best
- 👤 Thomas A. Lindroth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 10:43
CPC Classifications
C; C04; C04B; C04B24/00; C04B24/24; C04B24/38; C12; C12P; C12P19/00; C12P19/04; Y; Y10; Y10S; Y10S435/00; Y10S435/8215; Y10S435/822; Y10S435/829
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
29 words
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.
Claim 2
Dependent Claim
29 words
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.
Claim 3
Dependent Claim
57 words
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.
References Cited (Backward Citations)
US4342866A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-15 | 1994-04-16 | 1994-10-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-15 | 1998-04-16 | 1998-10-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-15 | 2002-04-16 | 2002-10-16 | $7700.00 | Window Closed / Lapsed |