Patent US4313863A successfully refreshed from Google Patents.
US4313863A
Expired / Lapsed
US
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Modification of acrylamide polymers
Assignee: Diafloc Co Ltd
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Filing: 1980-11-28
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Granted: 1982-02-02
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Expires: 2000-11-28
Abstract
Abstract When an alkaline substance is added to and mixed with aggregates of the mutually adhering blobs of a hydrogel of an acrylamide polymer, (1) a mixing tank in which the portion to be contacted with the hydrogel of an acrylamide polymer is made of a chromium-plated material is used, and (2) to said hydrogel aggregates is added at least one compound represented by the general formulae: HO[C3H6O]nH (I) <IMAGE> (II) <IMAGE> (III) wherein R1 is a residue obtained by removing two OH groups from a saturated dihydric alcohol having 2 to 4 carbon atoms, and R2 is a residue obtained by removing three OH groups from a saturated trihydric alcohol having 3 to 6 carbon atoms, and having an average molecular weight of 500 to 5,000, whereby the hydrolysis of the acrylamide polymer can be achieved at a high efficiency while preventing the mutual adhesion of the hydrogel aggregates and also reducing the adhesion of the aggregates to the interior surface of the mixing tank to such an extent that there is substantially no problem of adhesion.
Inventors
- 👤 Ryoji Handa
- 👤 Norimasa Yoshida
- 👤 Jun Hosoda
- 👤 Akihisa Furuno
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 18:03
CPC Classifications
C; C08; C08F; C08F8/00; C08F8/12; Y; Y10; Y10S; Y10S524/00; Y10S524/916
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
167 words
A method for modifying an acrylamide polymer with an inorganic alkaline substance by adding the inorganic alkaline substance to the hydrogel aggregates of the acrylamide polymer in a mixing tank to hydrolyze the polymer, characterized in that the mixing tank has a chromium-plated internal surface with which the hydrogel aggregates of the acrylamide polymer contact, and that at least one compound selected from the group consisting of the compounds represented by the following general formulae (I), (II) and (III): ##STR4## wherein R 1 is a residue obtained by removing two OH groups from a saturated dihydric alcohol having 2 to 4 carbon atoms, and R 2 is a residue obtained by removing three OH groups from a trihydric alcohol having 3 to 6 carbon atoms, and n's are such numerical values that any of the compounds represented by the general formulae (I), (II) and (III) has an average molecular weight within the range of 500 to 5,000, is added to said hydrogel aggregates as an anti-tack agent.
Claim 2
Independent Claim
167 words
A method for modifying an acrylamide polymer with an inorganic alkaline substance by adding the inorganic alkaline substance to the hydrogel aggregates of the acrylamide polymer in a mixing tank to hydrolyze the polymer, characterized in that the mixing tank has a chromium-plated internal surface with which the hydrogel aggregates of the acrylamide polymer contact, and that at least one compound selected from the group consisting of the compounds represented by the following general formulae (I), (II) and (III): ##STR4## wherein R 1 is a residue obtained by removing two OH groups from a saturated dihydric alcohol having 2 to 4 carbon atoms, and R 2 is a residue obtained by removing three OH groups from a trihydric alcohol having 3 to 6 carbon atoms, and n's are such numerical values that any of the compounds represented by the general formulae (I), (II) and (III) has an average molecular weight within the range of 500 to 5,000, is added to said hydrogel aggregates as an anti-tack agent.
Claim 3
Dependent Claim
37 words
The method according to claim 1, wherein at least one compound represented by the general formula (I), (II) or (III) having a molecular weight within the range of 1,000 to 4,000 is used as the anti-tack agent.
Claim 4
Dependent Claim
28 words
The method according to claim 1, wherein the anti-tack agent is used in an amount of 0.01 to 0.5% by weight based on the weight of the polymer.
Claim 5
Dependent Claim
16 words
The method according to claim 1, 2 or 3, wherein the anti-tack agent is polypropylene glycol.
Claim 6
Dependent Claim
38 words
The method according to claim 1, 2 or 3, wherein the anti-tack agent is a compound represented by the general formula (II) in which R 1 is the residue of ethylene glycol, propylene, glycol, tetramethylene glycol or 2,3-butanediol.
Claim 7
Dependent Claim
34 words
The method according to claim 1, 2 or 3, wherein the anti-tack agent is a compound represented by the general formula (III), in which R 2 is the residue of glycerin, 2-methyl-2-oxymethyl-1,3-propanediol, or 2-ethyl-2-oxymethyl-1,3-propanediol.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the inorganic alkaline substance is sodium hydroxide.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the inorganic alkaline substance is sodium carbonate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-02-01 | 1985-08-03 | 1986-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-01 | 1989-08-03 | 1990-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-01 | 1993-08-03 | 1994-02-02 | $7700.00 | Window Closed / Lapsed |