EP0302650A1
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EP
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Hydrophilic microporous membrane and process for preparing same
Assignee: Asahi Kasei Corp
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Filing: 1988-07-26
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Granted: —
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Expires: 2008-07-26
Abstract
Abstract A hollow fiber microporous membrane of a polyolefin having a polyvinyl alcohol chemically bonded to the inner and outer surfaces of the hollow fiber membrane and the surfaces defining the pores thereof exhibits a good hydrophilic property as well as good chemical resistance, mechanical strength, water permeation performance and durability. This membrane has an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80%. The polyvinyl alcohol/polyolefin composition ratio is constant in the membrane thickness direction of the hollow fiber, the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 10 to 50%, and the condition defined by the ratio X/2 ≧ Y is satisfied between said oxygen/carbon atomic ratio X and the oxygen/carbon atomic ratio Y in the entire microporous membrane. The membrane is prepared by irradiating a hollow fiber microporous membrane of a polyolefin with ionizing radiations, reacting the membrane with vinyl acetate and then hydrolyzing the membrane.
Inventors
- 👤 Morikazu Miura
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 01:45
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0093; B01D67/00931; B01D69/00; B01D69/08; C; C08; C08J; C08J9/00; C08J9/36; C08J9/40; C08J9/405; B01D2323/00; B01D2323/38; B01D2323/385; C08J2323/00; C08J2323/02
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
116 words
A hollow fiber microporous membrane of a polyolefin having a polyvinyl alcohol chemically bonded to the inner and outer surfaces of the hollow fiber membrane and the surfaces defining the pores thereof and having an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80%, wherein the polyvinyl alcohol-polyolefin composition ratio is constant in the membrane thickness direction of the hollow fiber, the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 10 to 50%, and the condition defined by the ratio X/2 ≧ Y is satisfied between said oxygen/carbon atomic ratio X and the oxygen /carbon atomic ratio Y in the entire microporous membrane.
Claim 2
Dependent Claim
116 words
A hollow fiber microporous membrane of a polyolefin having a polyvinyl alcohol chemically bonded to the inner and outer surfaces of the hollow fiber membrane and the surfaces defining the pores thereof and having an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80%, wherein the polyvinyl alcohol-polyolefin composition ratio is constant in the membrane thickness direction of the hollow fiber, the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 10 to 50%, and the condition defined by the ratio X/2 ≧ Y is satisfied between said oxygen/carbon atomic ratio X and the oxygen /carbon atomic ratio Y in the entire microporous membrane.
Claim 3
Dependent Claim
44 words
A hollow fiber microporous membrane as set forth in claim 1, wherein the pore structure of the membrane is a three-dimensional network structure and the membrane has an inner diameter of 0.1 to 10 mm and a wall thickness of 0.05 to 5 mm.
Claim 4
Dependent Claim
16 words
A hollow fiber microporous membrane as set forth in claim 1, wherein the polyolefin is polyethylene.
Claim 5
Dependent Claim
16 words
A hollow fiber microporous membrane as set forth in claim 1, wherein the polyolefin is polypropylene.
Claim 6
Dependent Claim
31 words
A hollow fiber microporous membrane as set forth in claim 1, wherein the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 15 to 50%.
Claim 7
Dependent Claim
31 words
A hollow fiber microporous membrane as set forth in claim 1, wherein the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 20 to 50%.
Claim 8
Dependent Claim
23 words
A hollow fiber microporous membrane as set forth in claim 1, wherein the condition defined by the ratio X/2.5 ≧ Y is satisfied.
Claim 9
Dependent Claim
22 words
A hollow fiber microporous membrane as set forth in claim 1, wherein condition defined by the ratio X/3 ≧ Y is satisfied.
Claim 10
Dependent Claim
164 words
A process for the preparation of a hollow fiber microporous membrane of a polyolefin having a polyvinyl alcohol chemically bonded to the inner and outer surfaces of the hollow fiber membrane and the surfaces defining the pores thereof and having an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80%, wherein the polyvinyl alcohol/polyolefin composition ratio is constant in the membrane thickness direction of the hollow fiber, the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 10 to 50%, and the condition defined by the ratio X/2 ≧ Y is satisfied between said oxygen/carbon atomic ratio X and the oxygen/carbon atomic ratio Y in the entire microporous membrane, said process comprising irradiating a hollow fiber microporous membrane of a polyolefin having an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80% with ionizing radiations, reacting the membrane with vinyl acetate and then hydrolyzing the membrane.
Claim 11
Dependent Claim
164 words
A process for the preparation of a hollow fiber microporous membrane of a polyolefin having a polyvinyl alcohol chemically bonded to the inner and outer surfaces of the hollow fiber membrane and the surfaces defining the pores thereof and having an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80%, wherein the polyvinyl alcohol/polyolefin composition ratio is constant in the membrane thickness direction of the hollow fiber, the oxygen/carbon atomic ratio X on the outer surface of the hollow fiber microporous membrane is 10 to 50%, and the condition defined by the ratio X/2 ≧ Y is satisfied between said oxygen/carbon atomic ratio X and the oxygen/carbon atomic ratio Y in the entire microporous membrane, said process comprising irradiating a hollow fiber microporous membrane of a polyolefin having an average pore diameter of 0.01 to 5 µm and a porosity of 20 to 80% with ionizing radiations, reacting the membrane with vinyl acetate and then hydrolyzing the membrane.
Claim 12
Dependent Claim
18 words
A process as set forth in claim 9, wherein the ionizing radiations are accelerated electron beams or γ-rays.
Claim 13
Dependent Claim
29 words
A process as set forth in claim 9, wherein the polyolefin membrane is irradiated with 5 to 30 Mrad of ionizing radiations at a temperature not higher than 30°C.
Claim 14
Dependent Claim
28 words
A process as set forth in claim 9, wherein the reaction of the polyolefin membrane with vinyl acetate is carried out at a temperature of -20°C to 50°C.
Claim 15
Dependent Claim
25 words
A process as set forth in claim 9, wherein the reaction of the polyolefin membrane with vinyl acetate is carried out in the gas phase.
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GB2058802A
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GB2082599A
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EP0203459A2
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