Applying a fluoropolymer film to a body

• US 5,516,561 A
• Filed: 04/26/1994
• Issued: 05/14/1996
• Est. Priority Date: 06/20/1991
• Status: Expired due to Term

• Current Assignee: British Technology Group Ltd.
• Original Assignee: British Technology Group Ltd.
• Inventors: Thomas, Thomas R.
• Primary Examiner(s): DUDASH, DIANA L
• Application Number:
  US08/167,966
• Time in Patent Office: 749 Days
• Field of Search: 427/255.6, 427/255.1, 427/490, 427/245, 427/534, 427/536
• US Class Current: 427/490
• CPC Class Codes: B01D 69/127 using electrical discharge or plasma-polymerisation
• CPC Class Codes: B01D 71/32 containing fluorine atoms
• CPC Class Codes: B01D 71/36 Polytetrafluoroethene
• CPC Class Codes: B05D 1/62 Plasma-deposition of organic layers plasma deposition in general C23C14/00, C23C16/00
• CPC Class Codes: B05D 3/144 of polymeric substrates
• CPC Class Codes: C08J 2327/18 Homopolymers or copolymers of tetrafluoroethylene
• CPC Class Codes: C08J 7/123 Treatment by wave energy or particle radiation C08J7/18 takes precedence
• CPC Class Codes: D06M 10/025 Corona discharge or low temperature plasma
• CPC Class Codes: D06M 10/10 Macromolecular compounds
• CPC Class Codes: D06M 14/34 Polyamides
• CPC Class Codes: D06M 15/256 containing fluorine
• CPC Class Codes: D06M 2101/22 Polymers or copolymers of halogenated mono-olefins
• CPC Class Codes: D06M 2400/01 Creating covalent bondings between the treating agent and the fibre
• CPC Class Codes: D21H 17/11 Halides
• CPC Class Codes: D21H 21/16 Sizing or water-repelling agents
• CPC Class Codes: D21H 23/44 Treatment with a gas or vapour
• CPC Class Codes: D21H 25/06 of impregnated or coated paper D21H25/08 takes precedence

Abstract

A thin fluoropolymer film is covalently bonded to a microporous ptfe film to make a bilayer for separation, filtration or reverse osmosis, by exposing the microporous film to perfluorocyclohexane under plasma.

Claims

1. A method of applying a fluoropolymer film to a porous or microporous film, comprising exposing the porous or microporous film to plasma irradiation wherein the plasma power is less than 5 w and to a supply of saturated molecules of the formula C_n F_2n, where n is from 4 to 8, causing scission of the molecules, whereby fragments combine on the surface of the porous or microporous film to form an adherent fluoropolymer layer.

3. A method according of claims 1 or 2, wherein the molecules are of cycloperfluoroalkane.

4. A method according to claims 1 or 2, wherein the molecules are of cyclo-C_n F_2n where n=4, 5, 7 or 8.

5. A method according to claims 1 or 2, wherein the molecules are of cycloperfluorohexane.

6. A method according to claims 1 or 2, wherein the porous or microporous film is etched before the application of said fluoropolymer film thereto.

7. A method according to claims 1 or 2, performed in a chamber evacuated to 0.01 to 5 torr.

8. A method according to claims 1 or 2, wherein the porous or microporous film is polytetrafluoroethylene.

2. A method of applying a fluoropolymer film to a porous or microporous film of carbonaceous polymer, comprising exposing the porous or microporous film to plasma irradiation wherein the plasma power is less than 5 w and to a supply of saturated molecules of the formula C_n F_2n, where n is from 4 to 8, causing scission of the molecules, whereby fragments combine on the surface of the porous or microporous film to form a fluoropolymer layer covalently bonded to the film.