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US 6,139,963 AGranted
Polyvinyl alcohol hydrogel and process for producing the same
AssigneeKuraray Co., Ltd.
InventorsHiroaki Fujii, Masanobu Abe, Keiko Oka
Life of this patent
Estimating the term…
Abstract
A polyvinyl alcohol hydrogel has a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m. This gel has a large surface area and high capability of adhering microorganisms and permeating liquid, thereby exhibiting excellent purifying function. Processes for producing the above hydrogel are also provided.
Claims12
A polyvinyl alcohol hydrogel having a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m, and obtained by one of the following process (1)-(4);
- (1) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- and
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- or
- (2) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- and
- removing from the obtained gel said polymer B partially or entirely;
- or
- (3) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- and
- effecting acetalization simultaneously with or after the above gelation;
- or
- (4) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation,
- effecting acetalization simultaneously with or after the above gelation;
- and
- removing from the gel obtained in the above step said polymer B partially or entirely.
20 more elements
A gel having the feature of forming by alkali treatment a polyvinyl alcohol hydrogel having a surface layer comprising a net-like structure, said net-like structure being formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m, wherein said polyvinyl alcohol hydrogel is obtained by one of the following processes (1)-(4);
- (1) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- and
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- or
- (2) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- and
- removing from the obtained gel said polymer B partially or entirely;
- or
- (3) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- and
- effecting acetalization simultaneously with or after the above gelation;
- or
- (4) adding to a mixed polymer solution containing a vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- effecting acetalization simultaneously with or after the above gelation;
- and
- removing from the gel obtained in the above step said polymer B partially or entirely.
20 more elements
A process for producing polyvinyl alcohol hydrogels, which comprises the steps of:
- adding to a mixed polymer solution containing vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- and
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation,
- wherein said polyvinyl alcohol hydrogels have a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m.
2 more elements
A process for producing polyvinyl alcohol hydrogels, which comprises the steps of:
- adding to a mixed polymer solution containing vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- and
- removing from the obtained gel said polymer B partially or entirely,
- wherein said polyvinyl alcohol hydrogels have a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m.
3 more elements
A process for producing polyvinyl alcohol hydrogels, which comprises the steps of:
- adding to a mixed polymer solution containing vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- and
- effecting acetalization simultaneously with or after the above gelation,
- wherein said polyvinyl alcohol hydrogels have a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m.
3 more elements
A process for producing polyvinyl alcohol hydrogels, which comprises the steps of:
- adding to a mixed polymer solution containing vinyl alcohol polymer (polymer A) and a polymer (polymer B) that gels on contact with a cation, a substance (substance C) capable of causing phase separation of said polymer solution, to prepare a phase-separated liquid,
- contacting said phase-separated liquid with a cation-containing liquid, to solidify the polymer B present at least on the surface of said phase-separated liquid;
- contacting the obtained solid with a coagulating liquid having coagulating function for said polymer A, to effect gelation;
- effecting acetalization simultaneously with or after the above gelation;
- and
- removing from the gel obtained in the above step said polymer B partially or entirely,
- wherein said polyvinyl alcohol hydrogels have a surface layer comprising a net-like structure formed by entanglement of fiber-like articles having a diameter of 0.1 to 50 .mu.m.
4 more elements
Dependencies are inferred from the claim text.