Patent EP0345017A1 successfully refreshed from Google Patents.
EP0345017A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Method for preparing granular porous chitosan
Assignee: Kurita Water Industries Ltd
•
Filing: 1989-05-30
•
Granted: —
•
Expires: 2009-05-30
Abstract
Abstract A method for preparing granular porous chitosan which comprises dispersing an acidic aqueous solution of chitosan in a hydrophobic dispersing medium; and, evaporating water off while stirring the resulting dispersion.
Inventors
- 👤 Chuichi Hirayama
- 👤 Hirotaka Ihara
- 👤 Junichi C/O Kurita Water Industries Ltd. Ida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 18:20
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/12; C08J3/14; B; B01; B01J; B01J20/00; B01J20/22; B01J20/24; C08B; C08B37/00; C08B37/0006; C08B37/0024; C08B37/0027; C08B37/003; C08J2305/00; C08J2305/08
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
36 words
A method for preparing granular porous chitosan which comprises: a step of dispersing an acidic aqueous solution of chitosan in a hydrophobic dispersing medium; and, a step of evaporating water off while stirring the resulting dispersion.
Claim 2
Independent Claim
36 words
A method for preparing granular porous chitosan which comprises: a step of dispersing an acidic aqueous solution of chitosan in a hydrophobic dispersing medium; and, a step of evaporating water off while stirring the resulting dispersion.
Claim 3
Dependent Claim
23 words
A method according to claim 1, wherein said chitosan is obtained by deacetylation and has an acetylation degree of 50 to 100 mol%.
Claim 4
Dependent Claim
56 words
A method according to claim 1, or claim 2 wherein said chitosan has a molecular weight of 5,000 to 1,000,000, an intrinsic viscosity (30°C, 0.2 M acetic acid + 0.1 M sodium acetate) of 0.25 to 20 dℓ/g-chitosan, a colloid equivalent of 1.0 to 6.2 meq/g-chitosan and a mean grain diameter of 9 to 300 mesh.
Claim 5
Independent Claim
26 words
A method according to any foregoing claim, wherein said acidic aqueous solution of chitosan contains a 0.5 to 5-fold amount of an acid based on chitosan.
Claim 6
Independent Claim
25 words
A method according to any foregoing claim, wherein a concentration of said chitosan in the acidic aqueous solution of chitosan is 0.1 to 20 wt%.
Claim 7
Independent Claim
35 words
A method according to any foregoing claim, wherein said hydrophobic dispersing medium is selected from a compound having a boiling point of not lower than 100°C and a compound that is azeotropically distillable with water.
Claim 8
Dependent Claim
31 words
A method according to claim 6, wherein said hydrophobic dispersing medium is selected from decahydronaphthalene (decalin), toluene, tetrahydronaphthalene (tetralin), xylene, ethylbenzene, diethylbenzene, anisole, hexanol, octanol, dibutyl ether, petroleum benzine and ligroin.
Claim 9
Independent Claim
28 words
A method according to any foregoing claim, wherein a ratio of said dispersion to the chitosan solution is in a range of approximately 100 : 1 to 100.
Claim 10
Independent Claim
20 words
A method according to any foregoing claim, wherein said dispersion is heated to 50 to 100°C to evaporate water off.
Claim 11
Independent Claim
34 words
A method according to any foregoing claim, wherein water is evaporated off by using a dispersing medium capable of being azeotropically distilled with water and heating to a temperature lower than the azeotropic point.
Claim 12
Dependent Claim
25 words
A method according to claim 10, wherein said dispersing medium capable of being azeotropically distilled with water is separated from water by reflux and re-used.
Claim 13
Dependent Claim
25 words
A method according to claim 10, wherein said dispersing medium capable of being azeotropically distilled with water is selected from benzene, cyclohexane, toluene and chloroform.
Claim 14
Independent Claim
30 words
A method according to any foregoing claim, wherein said stirring is performed at a rotation number of 300 to 5,000 r.p.m. at a peripheral speed of 1 to 20 m/sec.
Claim 15
Independent Claim
22 words
A method according to any foregoing claim, wherein at least 80 wt% of water is evaporated off from the acidic aqueous solution.
Claim 16
Independent Claim
17 words
A method according to any foregoing claim, wherein a surface active agent is added to the dispersion.
Claim 17
Dependent Claim
30 words
A method according to claim 6, wherein an organic compound capable of being azeotropically distilled with water is selected from benzene, methanol, ethanol, acetone, cyclohexane, toluene, choloroform, 2-pentanone or 3-pentanone.
References Cited (Backward Citations)
DE3527482A1
Cited
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.