US5141973A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing polyvinyl alcohol gel
Assignee: Eneos Corp
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Filing: 1989-12-27
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Granted: 1992-08-25
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Expires: 2009-12-27
Abstract
Abstract A method of preparing a polyvinyl alcohol hydrogel contains the steps of charging an aqueous solution of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol % and an average polymerization degree of not less than 500 into a container, the aqueous solution containing the polyvinyl alcohol in a concentration of not less than 5 wt. %, cooling the aqueous solution of the polyvinyl alcohol at a temperature of from - (minus) 9° C. to - (minus) 3° C., subjecting the aqueous solution of the polyvinyl alcohol to physical stimulation, and then maintaining the aqueous solution of the polyvinyl alcohol at a temperature of from - (minus) 5° C. to + (plus) 5° C. The polyvinyl alcohol hydrogel may be contained in a plastic container. An MRI phanton is composed of the plastic container containing such polyvinyl alcohol hydrogel.
Inventors
- 👤 Tomokazu Kobayashi
- 👤 Toshio Morihiro
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 02:19
CPC Classifications
C; C08; C08J; C08J3/00; C08J3/02; C08J3/03; G; G01; G01R; G01R33/00; G01R33/20; G01R33/28; G01R33/281; G01R33/44; G01R33/48; G01R33/58; C08J2329/00; C08J2329/02; C08J2329/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
170 words
A method of preparing a polyvinyl alcohol hydrogel, comprising the steps of charging an aqueous solution of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol % and an average polymerization degree of not less than 500 into a container, said aqueous solution containing said polyvinyl alcohol in a concentration of not less than 5 wt %, cooling said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 9° C. to - (minus) 3° C., subjecting said aqueous solution of said polyvinyl alcohol to physical stimulation by the application of stimulating means selected from the group consisting of vibrating sonic wave, ultrasonic wave, change in pressure, change in temperature and irradiation of a laser beam or by the addition of a material selected from the group consisting of water, ice, a polyvinyl alcohol gel and mixtures thereof, and then maintaining said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 5° C. to + (plus) 5° C.
Claim 2
Independent Claim
170 words
A method of preparing a polyvinyl alcohol hydrogel, comprising the steps of charging an aqueous solution of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol % and an average polymerization degree of not less than 500 into a container, said aqueous solution containing said polyvinyl alcohol in a concentration of not less than 5 wt %, cooling said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 9° C. to - (minus) 3° C., subjecting said aqueous solution of said polyvinyl alcohol to physical stimulation by the application of stimulating means selected from the group consisting of vibrating sonic wave, ultrasonic wave, change in pressure, change in temperature and irradiation of a laser beam or by the addition of a material selected from the group consisting of water, ice, a polyvinyl alcohol gel and mixtures thereof, and then maintaining said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 5° C. to + (plus) 5° C.
Claim 3
Independent Claim
176 words
A method of preparing a polyvinyl alcohol hydrogel contained in a plastic container, comprising the steps of charging an aqueous solution of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol % and an average polymerization degree of not less than 500 into a plastic container, said aqueous solution containing said polyvinyl alcohol in a concentration of not less than 5 wt %, cooling said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 9° C. to - (minus) 3° C., subjecting said aqueous solution of said polyvinyl alcohol to physical stimulation by the application of stimulating means selected from the group consisting of vibrating sonic wave, ultrasonic wave, change in pressure, change in temperature and irradiation of a laser beam or by the addition of a material selected from the group consisting of water, ice, a polyvinyl alcohol gel and mixtures thereof, and then maintaining said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 5° C. to + (plus) 5° C.
Claim 4
Independent Claim
176 words
A method of preparing a polyvinyl alcohol hydrogel contained in a plastic container, comprising the steps of charging an aqueous solution of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mol % and an average polymerization degree of not less than 500 into a plastic container, said aqueous solution containing said polyvinyl alcohol in a concentration of not less than 5 wt %, cooling said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 9° C. to - (minus) 3° C., subjecting said aqueous solution of said polyvinyl alcohol to physical stimulation by the application of stimulating means selected from the group consisting of vibrating sonic wave, ultrasonic wave, change in pressure, change in temperature and irradiation of a laser beam or by the addition of a material selected from the group consisting of water, ice, a polyvinyl alcohol gel and mixtures thereof, and then maintaining said aqueous solution of said polyvinyl alcohol at a temperature of from - (minus) 5° C. to + (plus) 5° C.
Claim 5
Dependent Claim
24 words
The method according to claim 1 or 2, wherein said polyvinyl alcohol has a degree of hydrolysis of not less than 98 mol %.
Claim 6
Dependent Claim
21 words
The method according to claim 1 or 2, wherein said polyvinyl alcohol has an average polymerization degree of 1000 to 1700.
Claim 7
Dependent Claim
22 words
The method according to claim 1 or 2, wherein said aqueous solution contains 5 to 50 wt % of said polyvinyl alcohol.
Claim 8
Dependent Claim
33 words
The method according to claim 1 or 2, wherein to said aqueous solution of said polyvinyl alcohol there is added one or more additives which do not hinder gelation of said polyvinyl alcohol.
Claim 9
Dependent Claim
62 words
The method according to claim 6, wherein said additive is selected from the group consisting of Mn 2+ , Ni 2+ , Cu 2+ , Fe 2+ , Fe 3+ , glycerin, methyl alcohol, ethyl [Ni 2+ , Cu 2+ , Fe 2+ , Fe 3+ , glycerin, methyl alcohol, ethyl] alcohol, isopropyl alcohol, acetone, agar, carrageenan, glucose, graphite and mixtures thereof.
Claim 10
Dependent Claim
13 words
The method according to claim 1, wherein said container is made of glass.
Claim 11
Dependent Claim
59 words
The method according to claim 2, wherein said container is made of a material selected from the group consisting of acrylic resins, polyvinylchloride resins, polyethylene, polypropylene, polyamides, polystyrene, celluloid, cellulose acetate, chlorinated rubbers, phenolic resins, urea resins, melamine resins, fluorinated resins, polycarbonate, polyacetal resins, polyalkyleneoxide, alkyd resins, furan resins, unsaturated polyester resins, epoxy resins, polyurethane resins, and silicon resins.
References Cited (Backward Citations)
US4012352A
Cited
US4734097A
Cited
US4472542A
Cited
US4939203A
Cited
US4774957A
Cited
US4772641A
Cited
US4916170A
Cited
US4737533A
Cited
US4788242A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-08-25 | 1996-02-24 | 1996-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-08-25 | 2000-02-24 | 2000-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-08-25 | 2004-02-24 | 2004-08-25 | $7700.00 | Window Closed / Lapsed |