
US Patent No: 5,141,973
Number of patents in Portfolio can not be more than 2000
Method of preparing polyvinyl alcohol gel
Stats
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Aug 25, 1992
Issued date -
Dec 27, 1989
filing date -
07/457,942
serial no -
Expired
status
Importance
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.degree. C. to - (minus) 3.degree. 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.degree. C. to + (plus) 5.degree. 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.
First Claim
Related Publications
International Classification(s)
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Cited Art
| Patent Info | (Count) | # Cites | Year |
|---|---|---|---|
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| 4,472,542 Freeze-dried polyvinyl alcohol gel | 44 | 1983 | |
| 4,734,097 Medical material of polyvinyl alcohol and process of making | 65 | 1985 | |
| 4,916,170 Process for making skin marker | 31 | 1988 | |
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| 4,939,203 Gel for retarding water flow | 5 | 1988 | |
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| 4,774,957 Material for diagnosis by nuclear magnetic resonance imaging | 35 | 1987 | |
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| 4,772,641 Aqueous sulfomethylated melamine gel-forming compositions | 4 | 1985 | |
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| 4,737,533 Dry material which can be hydrated into an aqueous gel, containing dispersed polymer particles, process for the preparation thereof and use thereof in biological applications | 15 | 1987 | |
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| 4,788,242 Polyvinyl alcohol-based reversibly hydrated gel, highly water-absorptive resin and method for the preparation thereof | 5 | 1987 | |