Patent US4152170A successfully refreshed from Google Patents.
US4152170A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cross-linked pullulan
Assignee: Hayashibara Seibutsu Kagaku Kenkyujo KK
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Filing: 1976-06-14
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Granted: 1979-05-01
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Expires: 1996-06-14
Abstract
Abstract Cross-linked pullulans are obtained by the reaction of pullulan with a cross-linking agent selected from the group consisting of polycarboxylic acids, halogenated dicarboxylic acids, polycarboxylic anhydrides, aldehyde compounds, N-methylol compounds, isocyanate compounds, metaphosphoric acid salts, divinyl compounds, bis-aziridine and bifunctional compounds of the formula, X--R--Z wherein X and Z are each a halogen atom or an epoxy group and R is an aliphatic residue having 1 to 30 carbon atoms, in a solvent, and are useful as gels or beds for chromatography or in various fields requiring high degrees of water absorbency and retention.
Inventors
- 👤 Tsuneyuki Nagase
- 👤 Kozo Tsuji
- 👤 Masanori Fujimoto
- 👤 Fujio Masuko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 05:07
CPC Classifications
C; C08; C08B; C08B37/00; C08B37/0006; C08B37/0009; C08B37/0018
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
77 words
A hydrophilic gel having a water absorption of 1 to 100 g/g at the swollen state in water which is obtained by adding dropwise an aqueous pullulan solution to a dispersion medium which is immiscible with said aqueous solution and contains a dispersion stabilizer to form a two-phase system, and adding epichlorohydrin to the two-phase system to effect the reaction between pullulan and epichlorohydrin, whereby said hydrophilic gel having a diameter of 10 to 500μ is obtained.
Claim 2
Dependent Claim
77 words
A hydrophilic gel having a water absorption of 1 to 100 g/g at the swollen state in water which is obtained by adding dropwise an aqueous pullulan solution to a dispersion medium which is immiscible with said aqueous solution and contains a dispersion stabilizer to form a two-phase system, and adding epichlorohydrin to the two-phase system to effect the reaction between pullulan and epichlorohydrin, whereby said hydrophilic gel having a diameter of 10 to 500μ is obtained.
Claim 3
Dependent Claim
34 words
A hydrophilic gel according to claim 1, wherein said reaction is carried out using said epichlorohydrin in a amount of 5 to 100 parts by weight based on 100 parts by weight of pullulan.
Claim 4
Dependent Claim
21 words
A hydrophilic gel according to claim 1, wherein said reaction is carried out at a temperature of 15° to 150° C.
Claim 5
Dependent Claim
34 words
A hydrophilic gel according to claim 1, wherein said reaction is carried out in the presence of a catalyst of at least 0.001 part by weight based on 100 parts by weight of pullulan.
Claim 6
Dependent Claim
31 words
A hydrophilic gel according to claim 1, wherein said dispersion medium is n-hexane, heptane, isoheptane, isooctane, benzene, toluene, xylene, kerosene, cyclohexane, methylcyclohexane, turpentine oil, dichloromethane, 1,2-dichloroethane, dichloropentane, monochlorobenzene, o-dichlorobenzene or trichlorobenzene.
Claim 7
Dependent Claim
24 words
A hydrophilic gel according to claim 1, wherein said dispersion stabilizer is polyvinyl acetate, polyisobutylene, cellulose acetate butyrate, polystyrene, polyethylvinyl ether or polymethyl methacrylate.
Claim 8
Independent Claim
81 words
A method for the preparation of a hydrophilic gel having a water adsorption of 1 to 100 g/g at the swollen state in water, which comprises adding dropwise an aqueous pullulan solution to a dispersion medium which is immiscible with said aqueous solution and contains a dispersion stabilizer to form a two-phase system, and adding epichlorohydrin to the two-phase system to effect the reaction between pullulan and epichlorohydrin, whereby said hydrophilic gel having a diameter of 10 to 500μ is obtained.
Claim 9
Independent Claim
81 words
A method for the preparation of a hydrophilic gel having a water adsorption of 1 to 100 g/g at the swollen state in water, which comprises adding dropwise an aqueous pullulan solution to a dispersion medium which is immiscible with said aqueous solution and contains a dispersion stabilizer to form a two-phase system, and adding epichlorohydrin to the two-phase system to effect the reaction between pullulan and epichlorohydrin, whereby said hydrophilic gel having a diameter of 10 to 500μ is obtained.
References Cited (Backward Citations)
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US3997703A
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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) | 1982-04-30 | 1982-10-30 | 1983-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-30 | 1986-10-30 | 1987-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-30 | 1990-10-30 | 1991-05-01 | $7700.00 | Window Closed / Lapsed |