US5071978A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silated polysaccharide process
Assignee: Aqualon Co
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Filing: 1990-09-28
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Granted: 1991-12-10
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Expires: 2010-09-28
Abstract
Abstract Silated polysaccharides having 0.005 to 2.0 silyl molar substitution per anhydrosaccharide unit form water resistant films when cast from aqueous solution and dried in the presence of atmospheric carbon dioxide. These films are soluble in aqueous caustic. A preferred water soluble polymer is a cellulose ether with 0.005 to 1.0 silyl substitution. A method for preparation involves: (1) reaction in a caustic medium; (2) recovering a neutralized silated polysaccharide; and (3) washing to remove impurities.
Inventors
- 👤 Arjun C. Sau
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 12:47
CPC Classifications
C; C08; C08B; C08B11/00; C08B11/193; C08B15/00; C08B15/05; C08B31/00; C08B31/08; C08B31/12; C08B37/00; C08B37/006; C08B37/0087; C08B37/0096
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
87 words
A method of preparing a silated polysaccharide containing from 0.005 to 2.0 hydrolytically stable silyl groups covalently bound to the polysaccharide per anhydrosaccharide unit, comprising the steps: (1) reacting a polysaccharide in a solvent and sodium hydroxide slurry with an organosilicon reagent having an epoxy, halogen, isocyanate or vinyl group; (2) neutralizing the reaction slurry with an acid to allow precipitation of a silated polysaccharide; (3) filtering the silated polysaccharide to remove liquid; and (4) washing the filtrate to remove impurities and recover a silated polysaccharide product.
Claim 2
Independent Claim
87 words
A method of preparing a silated polysaccharide containing from 0.005 to 2.0 hydrolytically stable silyl groups covalently bound to the polysaccharide per anhydrosaccharide unit, comprising the steps: (1) reacting a polysaccharide in a solvent and sodium hydroxide slurry with an organosilicon reagent having an epoxy, halogen, isocyanate or vinyl group; (2) neutralizing the reaction slurry with an acid to allow precipitation of a silated polysaccharide; (3) filtering the silated polysaccharide to remove liquid; and (4) washing the filtrate to remove impurities and recover a silated polysaccharide product.
Claim 3
Dependent Claim
14 words
The method of claim 1 where in step (1) the caustic is sodium hydroxide.
Claim 4
Dependent Claim
14 words
The method of claim 2 where in step (1) the solvent is t-butyl alcohol.
Claim 5
Dependent Claim
14 words
The method of claim 3 where in step (2) the acid is nitric acid.
Claim 6
Dependent Claim
17 words
The method of claim 4 where in step (1) the organosilicon reagent is (3-glycidoxypropyl)trimethoxysilane or vinyl trimethoxysilane.
Claim 7
Dependent Claim
12 words
The method of claim 5 where the polysaccharide is a cellulose ether.
Claim 8
Dependent Claim
11 words
The method of claim 6 where the cellulose ether is hydroxyethylcellulose.
Claim 9
Dependent Claim
12 words
The method of claim 5 where the polysaccharide is a guar ether.
Claim 10
Dependent Claim
13 words
The method of claim 8 where the guar ether is carboxymethylguar or hydroxypropylguar.
Claim 11
Dependent Claim
26 words
The method of claim 5 where the polysaccharide is selected from the group of guar gum, xanthan gum, starch, starch ether, chitosan, dextran or cationic hydroxyethylcellulose.
Claim 12
Independent Claim
80 words
A method of preparing a silated polysaccharide comprises the steps: (1) reacting a polysaccharide in the presence of a caustic with a quantity of a silating agent sufficient to covalently bond from 0.005 to 2.0 anhydrosaccharide units, (2) neutralizing with nitric acid to allow precipitation of a silated polysaccharide with silyl groups attached to from 0.005 to 2.0 anhydrosaccharide units; (3) filtering to remove liquid; (4) washing with water and acetone; and (5) drying to recover a silated polysaccharide product.
Claim 13
Independent Claim
80 words
A method of preparing a silated polysaccharide comprises the steps: (1) reacting a polysaccharide in the presence of a caustic with a quantity of a silating agent sufficient to covalently bond from 0.005 to 2.0 anhydrosaccharide units, (2) neutralizing with nitric acid to allow precipitation of a silated polysaccharide with silyl groups attached to from 0.005 to 2.0 anhydrosaccharide units; (3) filtering to remove liquid; (4) washing with water and acetone; and (5) drying to recover a silated polysaccharide product.
Claim 14
Dependent Claim
26 words
The method of claim 11 where polysaccharide is from the group of cellulose ether, guar gum, guar ether, starch, starch ether, xanthan gum, chitosan or dextran.
Claim 15
Dependent Claim
17 words
The method of claim 12 where in step (1) the silating agent is (3-glycidoxypropyl)trimethoxysilane or vinyl trimethoxysilane.
Claim 16
Dependent Claim
14 words
The method of claim 13 where in step (1) the caustic is sodium hydroxide.
Claim 17
Dependent Claim
11 words
The method of claim 14 where the cellulose ether is hydroxyethylcellulose.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-12-09 | 1995-06-10 | 1995-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-12-09 | 1999-06-10 | 1999-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-12-09 | 2003-06-10 | 2003-12-10 | $7700.00 | Window Closed / Lapsed |