Oil-and water repellent gas-permeable filter

• US 5,462,586 A
• Filed: 09/07/1994
• Issued: 10/31/1995
• Est. Priority Date: 09/08/1993
• Status: Expired due to Term

• Current Assignee: Asahi Glass Company, Limited (AGC, Inc.), Japan Gore-Tex Inc
• Original Assignee: Japan Gore-Tex Inc
• Inventors: Moriyama, Sumihiro, Sasaki, Fumihiro, Nakamura, Masaru, Sugiyama, Norihide
• Primary Examiner(s): SPITZER, ROBERT H
• Application Number:
  US08/301,529
• Time in Patent Office: 419 Days
• Field of Search: 55/524, 55/528, 96/11-14
• US Class Current: 96/13
• CPC Class Codes: B01D 2239/0478 on a layer of the filter
• CPC Class Codes: B01D 2239/0618 Non-woven
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material apparatus incorporating such gas filtering material B01D2275/10
• CPC Class Codes: B01D 39/083 of organic material
• CPC Class Codes: B01D 67/0088 Physical treatment with compounds, e.g. swelling, coating or impregnation
• CPC Class Codes: B32B 2305/026 Porous
• CPC Class Codes: B32B 2307/724 Permeability to gases, adsorption
• CPC Class Codes: B32B 2307/7265 Non-permeable
• CPC Class Codes: B32B 27/08 of synthetic resin
• CPC Class Codes: B32B 27/10 of paper or cardboard
• CPC Class Codes: B32B 27/12 next to a fibrous or filamentary layer
• CPC Class Codes: B32B 27/322 comprising halogenated polyolefins, e.g. PTFE
• CPC Class Codes: B32B 5/022 Non-woven fabric
• CPC Class Codes: B32B 5/024 Woven fabric
• CPC Class Codes: B32B 5/026 Knitted fabric
• CPC Class Codes: B32B 5/24 one layer being a fibrous or filamentary layer

Abstract

An oil- and water-repellent filter which contains a porous filter material that has its internal and external surfaces coated with a compound formed by combining a fluoropolymer having a fluorine-containing aliphatic cyclic structure in the main chain and a fluoropolymer containing polyfluoroalkyl groups. The coating imparts superior oil- and water-repellency without impairment to the flow of air or other gases through the filter.

Claims

1. An oil- and water-repellent gas-permeable filter comprising:

(a) a gas-permeable material having a structure containing passageways therethrough, said material having its internal and external surfaces coated with a compound comprising

(i) a fluoropolymer A having a fluorine-containing aliphatic cyclic structure in the main chain, and

(ii) a fluoropolymer B containing polyfluoroalkyl groups,

wherein the relative concentration of the fluoropolymers is in the range 1 weight part A to 0.01-100 weight parts B.

2. The oil- and water-repellent gas-permeable filter as recited in claim 1, wherein the fluoropolymer B contains at least 80 wt % (meth)acrylate monomer groups having C_n F_2n+1 (where n=4 to 20) as the polyfluoroalkyl groups.

3. The oil- and water-repellent gas-permeable filter as recited in claim 1, wherein the gas-permeable material is selected from the class consisting of woven fabric, knitted fabric, non-woven fabric, netting, felt, porous synthetic polymer sheets, cellulosic papers, and fiberglass papers.

4. The oil- and water-repellent gas-permeable filter as recited in claim 2, wherein the gas-permeable material is selected from the class consisting of woven fabric, knitted fabric, non-woven fabric, netting, felt, porous synthetic polymer sheets, cellulosic papers, and fiberglass papers.

5. The oil- and water-repellent gas-permeable filter as recited in claim 1, 2, 3, or 4, wherein the gas-permeable material is polytetrafluoroethylene.

6. The oil- and water-repellent gas-permeable filter as recited in claim 1, wherein the gas-permeable material is a composite material comprising a porous polytetrafluoroethylene membrane laminated to a material selected from the class consisting of woven fabric, knitted fabric, non-woven fabric, netting, felt, porous synthetic polymer sheets, cellulosic papers, and fiberglass papers.