Claims
- 1. A hydrophilic porous membrane, comprising a porous membrane made of a hydrophobic polymer and a coating formed on at least one surface of said porous membrane and on the inner surface of porous of said porous membrane with a water-insoluble vinyl alcohol-vinyl acetate copolymer having a saponification degree of 15 to 60 mol % and soluble in a solvent exhibiting satisfactory stability and a satisfactory wetting property with respect to said hydrophobic polymer.
- 2. A hydrophilic porous membrane according to claim 1, wherein said hydrophobic polymer is a fluorine resin type polymer or a polyolefin type polymer.
- 3. A hydrophilic porous membrane according to claim 1, wherein said hydrophobic polymer is a fluorine resin type polymer.
- 4. A hydrophilic porous membrane according to claim 3, wherein said fluorine resin type polymer is polyvinylidene fluoride.
- 5. A hydrophilic porous membrane according to claim 1 wherein the saponification of said water insoluble vinyl alcohol-vinyl acetate copolymer is 25 to 45 mol %.
- 6. A hydrophilic porous membrane according to claim 5 wherein the porous membrane has a thickness of 100 to 200 .mu.m and an average pore diameter of 0.1 to 0.6 .mu.m.
- 7. A method according to claim 6, wherein said solvent is at least one member selected from the group consisting of methanol, ethanol, isopropanol, and mixtures of said alcohols with water.
- 8. A hydrophilic porous membrane according to claim 1 wherein the porous membrane has a thickness of 50 to 300 .mu.m and an average pore diameter of 0.1 to 1.0 .mu.m.
- 9. A method for the manufacture of a hydrophilic porous membrane, comprising the steps of:
- (a) preparing a porous membrane of a hydrophobic polymer,
- (b) impregnating said porous membrane with a solution obtained by dissolving a water-insoluble vinyl alcohol-vinyl acetate copolymer having 15 to 60 mol% of saponification degree in a solvent exhibiting a satisfactory ability to dissolve said copolymer, and exhibiting satisfactory stability and a satisfactory wetting property with respect to said hydrophobic polymer, wherein the concentration of said hydrophilic polymer in said solution is in the range of 0.1 to 10% by weight, and the duration of said impregnation of said porous membrane of a hydrophobic polymer with said solution of water-insoluble hydrophilic polymer is in the range of 1 to 30 seconds, and
- (c) drying the impregnated porous membrane to adhere said hydrophilic polymer with said hydrophobic polymer.
- 10. A method according to claim 9, wherein said hydrophobic polymer is a fluorine resin type polymer or a polyolefin type polymer.
- 11. A method according to claim 9, wherein said hydrophobic polymer is a fluorine resin type polymer.
- 12. A method according to claim 11, wherein said fluorine resin type polymer is polyvinylidene fluoride.
- 13. A method according to claim 9, wherein said impregnation of said porous membrane of a hydrophobic polymer with the solution of said water-insoluble hydrophilic polymer is effected by immersion of said porous membrane in said solution.
- 14. A method according to claim 9, wherein the saponification of said water insoluble vinyl alcohol-vinyl acetate copolymer is 25 to 45 mol %.
- 15. A method according to claim 9, wherein drying said hydrophilic porous membrane is carried out at a temperature of 60.degree.-80.degree. C.
Priority Claims (1)
Number |
Date |
Country |
Kind |
60-1420 |
Jan 1985 |
JPX |
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Parent Case Info
This is a continuation of application Ser. No. 815,643, filed Jan. 2, 1986, now abandoned.
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
4419187 |
Cheng et al. |
Dec 1983 |
|
4432875 |
Wrasidlo et al. |
Feb 1984 |
|
4438185 |
Taskier |
Mar 1984 |
|
Continuations (1)
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Number |
Date |
Country |
Parent |
815643 |
Jan 1986 |
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