EP0160551A2
Expired / Lapsed
EP
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A Polyethylene microporous membrane and a process for the production thereof
Assignee: Tonen General Sekiyu KK
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Filing: 1985-04-26
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Granted: —
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Expires: 2005-04-26
Abstract
Abstract polyethylene microporous membrane having a thickness of not more than 10µm, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30% is produced by heating and dissolving polyethylene having a weight average molecular weight of at least 5 x 10 5 in a solvent, forming a gel sheet from the resulting solution, subjecting the gel sheet to a solvent removal treatment to adjust the amount of the solvent in the gel sheet to 10 to 80% by weight, heating and stretching the sheet and then removing the residual solvent therefrom.
Inventors
- 👤 Koichi Kono
- 👤 Shoichi Mori
- 👤 Kenji Miyasaka
- 👤 Jyoichi Tabuchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 13:49
CPC Classifications
C; C08; C08J; C08J5/00; C08J5/18; B; B01; B01D; B01D67/00; B01D67/0002; B01D67/0009; B01D67/00091; B01D67/0023; B01D67/0025; B01D67/0027; B01D67/0039; B01D67/0046; B01D71/00; B01D71/06; B01D71/26; B01D71/261; B01D2323/00; B01D2323/08; B01D2323/081; B01D2323/12; B01D2325/00; B01D2325/02; B01D2325/0283; B01D2325/04; C08J2323/00; C08J2323/02; C08J2323/04; C08J2323/06; Y; Y10; Y10S; Y10S264/00; Y10S264/71; Y10S521/00; Y10S521/918; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249953; Y10T428/249978
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
45 words
A microporous polyethylene membrane consisting of polyethylene having a weight average molecular weight of at least 5 x 105, and having a thickness of not more than 10 m, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30%.
Claim 2
Dependent Claim
45 words
A microporous polyethylene membrane consisting of polyethylene having a weight average molecular weight of at least 5 x 105, and having a thickness of not more than 10 m, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30%.
Claim 3
Dependent Claim
42 words
A micorporous polyethylene membrane as claimed in Claim 1 which has a thickness in the range of from 0.1 to 10 m, a breaking strength of at least 200 kg/cm 2 and a porosity in the range of from 30 to 95%.
Claim 4
Dependent Claim
34 words
A polyethylene microporous membrane as claimed in Claim 1 or Claim 2 wherein the weight average molecular weight is in the range of from 1 x 10 6 to 10 x 10 6 .
Claim 5
Dependent Claim
101 words
A process for the production of a microporous polyethylene membrane having a thickness of not more than 10 m, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30%, which comprises heating and dissolving polyethylene having a weight average molecular weight of at least 5 x 10 in a solvent, forming a gel sheet from the resulting solution, subjecting the gel sheet to a solvent removal to adjust the amount of the solvent in the gel sheet to 10 to 80% by weight, heating and stretching the sheet and then removing the residual solvent therefrom.
Claim 6
Dependent Claim
101 words
A process for the production of a microporous polyethylene membrane having a thickness of not more than 10 m, a breaking strength of at least 200 kg/cm 2 and a porosity of at least 30%, which comprises heating and dissolving polyethylene having a weight average molecular weight of at least 5 x 10 in a solvent, forming a gel sheet from the resulting solution, subjecting the gel sheet to a solvent removal to adjust the amount of the solvent in the gel sheet to 10 to 80% by weight, heating and stretching the sheet and then removing the residual solvent therefrom.
Claim 7
Dependent Claim
30 words
A process as claimed in Claim 4 wherein the solvent is an aliphatic or cyclic hydrocarbon, a paraffin oil or a mineral oil fraction having a boiling point corresponding thereto.
Claim 8
Dependent Claim
15 words
A process as claimed in Claim 5, where in the solvent is a paraffin oil.
Claim 9
Dependent Claim
31 words
A process as claimed in any one of Claims 4 to 6 wherein the heating and dissolving is carried out at a temperature in the range of from 140 to 250°C.
Claim 10
Dependent Claim
29 words
A process as claimed in any one of Claims 4 to 7 wherein the solution has a polyethylene content in the range of from 1 to 10% by weight.
Claim 11
Dependent Claim
74 words
A process as claimed in any one of Claims 4 to 8 wherein the forming of the gel sheet is carried out by extruding the polyethylene solution through a die or spreading it over a support, cooling and gelling at a temperature below the gelling temperature and at a cooling rate of at least 50°C/min and then forming into a gel sheet with a thickness in the range of from 0.1 to 5 mm.
Claim 12
Dependent Claim
19 words
A process as claimed in Claim 9 wherein the temperature is in the range of from 15 to 25°C.
Claim 13
Dependent Claim
32 words
A process as claimed in Claim 9 or Claim 10 wherein the solvent removal treatment is carried out by immersing the gel sheet in a readily volatile solvent to extract the solvent.
Claim 14
Dependent Claim
26 words
A process as claimed in Claim 11 wherein the readily volatile solvent is a hydrocarbon, a chlorinated hydrocarbon, a fluorinated hydrocarbon, an ether or an alcohol.
Claim 15
Dependent Claim
51 words
A process as claimed in Claim 11 or Claim 12 wherein the solvent removal treatment is carried out in such a manner that the gel sheet shrinks with a shrinkage of at least 50% in the direction of its thickness and at the most 20% in the longitudinal and lateral directions.
Claim 16
Dependent Claim
46 words
A process as claimed in any one of Claims 4 to 13 wherein the heating and stretching is carried out biaxially simultaneously or in sequence at a temperature of from the -dispersion temperature to the crystal melting point of the polyethylene of the base stock sheet.
Claim 17
Dependent Claim
19 words
A process as claimed in Claim 14 wherein the temperature is in the range of from 90 to 140°C.
Claim 18
Dependent Claim
24 words
A process as claimed in Claim 14 or 15 wherein the stretching is carried out with a surface magnification of at least 10 times.
References Cited (Backward Citations)
No citation records indexed.
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