Process for producing a porous track membrane
AssigneeDressel Pte. Ltd.
InventorsAndrey Viktorovich Desyatov, Alexei Valerievich Egorov
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Abstract
Porous track membranes are produced by exposing a polymeric film to a bombardment of heavy ions to provide the film with a track density, and etching pores into the resulting tracked film with an etching solution to provide the film with a density of the pores corresponding to the track density under conditions to maintain turbulent flow. An alkaline etching solution is used that contains salts of alkali metals in sufficient concentration to increase the boiling point of the resulting alkali-metal-containing solution to temperatures in excess of about 100 up to about 150° C.
Claims23
A process for producing a porous track membrane useful in the separation of materials from a fluid comprising the steps of:
- a) exposing a film of polyvinylidene fluoride to a bombardment of heavy ions to provide the film with a track density, wherein heavy ions are defined to have a mass greater than or equal to argon ions;
- and
- b) etching pores into the resulting tracked film with an etching solution at temperatures in a range of 100° to 150°C., said etching solution is an alkaline solution of potassium permanganate and containing at least one non-basic salt of alkali metals in sufficient concentration to increase the boiling point of the resulting alkali metal-containing solution, and circulating the etching solution over and in contact with the etching film at a flow rate to produce a Reynolds Number in the range from 100 to 500 to provide the film with a density of the pores corresponding to the track density.
A process for producing a porous track membrane useful in the separation of materials from a fluid comprising the steps of:
- a) exposing a film of polyvinylidene fluoride film to a bombardment of heavy ions to provide the film with a track density, wherein heavy ions are defined to have a mass greater than or equal to argon ions;
- b) cutting the resulting tracked film into a plurality of separate sections;
- and
- c) etching the sections of tracked film with an etching solution to provide the sections of film with a density of pores corresponding to the track density at temperatures in a range of 100° to 150° C., said etching solution is an alkaline solution of potassium permanganate and containing at least one non-basic salt of alkali metals in sufficient concentration to increase the boiling point of the resulting alkali-metal-containing solution, and under flow rate conditions to maintain a Reynolds Number in the range from 100 to 500.
A process for producing a porous track membrane useful in the separation of materials from a fluid comprising the steps of:
- a) exposing a continuous roll of film of polyvinylidene fluoride film to a bombardment of heavy ions to provide the film with a track density;
- and
- b) etching the continuous roll of tracked film as the roll passes through an etching solution to provide the sections of film with a density of pores corresponding to the track density at temperatures in a range of 100° to 150° C., said etching solution is an alkaline solution of potassium permanganate and containing at least one non-basic salt of alkali metals in sufficient concentration to increase the boiling point of the resulting alkali-metal-containing solution, and under flow rate conditions to maintain a Reynolds Number in the range from 100 to 500.
Dependencies are inferred from the claim text.