process for treating a porous substrate to achieve improved water and oil repellency

• US 5,156,780 A
• Filed: 07/18/1990
• Issued: 10/20/1992
• Est. Priority Date: 07/24/1989
• Status: Expired due to Term

• Current Assignee: Pall Corporation (Danaher Corporation)
• Original Assignee: Gelman Sciences, Inc. (Danaher Corporation)
• Inventors: Shchori, Ehud, Kenigsberg, Yitzchak
• Primary Examiner(s): Tentoni, Leo B.
• Application Number:
  US07/554,263
• Time in Patent Office: 825 Days
• Field of Search: 264/22, 264/44, 264/45.1, 264/48, 264/41, 210/500.21, 210/506, 8/115.52, 8/115.53, 8/115.64, 427/44, 427/244
• US Class Current: 264/424
• CPC Class Codes: B01D 67/0088 Physical treatment with compounds, e.g. swelling, coating or impregnation
• CPC Class Codes: C08F 220/22 Esters containing halogen
• CPC Class Codes: C09D 4/00 Coating compositions, e.g. paints, varnishes or lacquers, based on organic non-macromolecular compounds having at least one polymerisable carbon-to-carbon unsaturated bond ; Coating compositions, based on monomers of macromolecular compounds of groups C09D183/00 - C09D183/16
• CPC Class Codes: D06M 14/20 on to materials of natural origin
• CPC Class Codes: D06N 3/047 with fluoropolymers
• CPC Class Codes: D21H 19/48 Diolefins, e.g. butadiene; Aromatic vinyl monomers, e.g. styrene; Polymerisable unsaturated acids or derivatives thereof, e.g. acrylic acid
• CPC Class Codes: D21H 21/16 Sizing or water-repelling agents

Abstract

Oil and water repellency is conferred upon porous substrates (10) by treatment with a solution of a monomer (16) of the formula: (C_n E_2n+1)(CH₂)_x (CHR)OCOCH═CH₂ where n is an integer; X is 0,1,2 or 3 and R is H or CH₂ --OCOCH═CH₂. The monomer is polymerized in situ upon the substrate to provide a conformal coating (16'"'"') which preserves the porous structure.

Claims

1. A method for treating a porous substrate (10) to achieve permanent water and oil repellency while maintaining the porosity thereof, the method comprising the steps of:

A) providing a fluoroacrylate monomer (16) of the formula (C_n F_2n+1) (CH₂)_x (CHR) OCOCH═

CH₂, where;

n is an integer, X is;

0, 1, 2 or 3 and R is;

H or CH₂ OCOCH═

CH₂ ;

B) disposing the monomer (16) in a carrier vehicle so as to form a mixture (14) thereof;

C) impregnating the substrate (10) with the monomer mixture (14);

d) removing substantially all of the vehicle from the substrate (10); and

E) initiating polymerization of the monomer (16) after substantially all of the vehicle is removed from the substrate whereby the monomer (16) is polymerized to form a conformal, oil and water repellant coating (16'"'"') which is mechanically adhered to the substrate.

2. A method as in claim 1, wherein said monomer (16) comprises a number of homologues corresponding to different values of n and wherein at least 5% of said homologues have a value of n which is at least 8.

3. A method as in claim 2, wherein at least 30% of said homologues have a value of n which is at least 8.

4. A method as in claim 2 wherein at least 50% of said homologues have a value of n which is at least 8.

5. A method as in claim 1, including the further step of providing an initiator which is activatable to cause polymerization of the monomer (16) and wherein the step of disposing the monomer (16) in a carrier vehicle includes the further step of disposing the initiator in the vehicle and wherein the step of initiating polymerization of the monomer (16) comprises activating the initiator.

6. A method as in claim 5, wherein the step of providing an intiator comprises providing a photoinitiator and the step of activating the initiator comprises irradiating the photoinitiator with light.

7. A method as in claim 5, wherein the step of providing an intiator comprises providing a free radical initiator and wherein the step of activating the initiator comprises heating the initiator.

8. A method as in claim 1, wherein the step of initiating polymerization of the monomer (16) comprises bombarding the monomer with an electron beam.

9. A method as in claim 1, including the further step of providing a cross-linking reagent so as to provide a monomer mixture and the step of disposing the monomer (16) in a carrier vehicle includes the further step of disposing said monomer mixture in the carrier vehicle and the step of initiating polymerization of the monomer (16) includes the further step of activating the cross-linking reagent.

10. A method as in claim 9, wherein the step of providing a cross-linking reagent comprises providing a member selected from the group consisting essentially of:

monoacrylates, diacrylates, triacrylates, polyacrylates, monoacrylamides and combinations thereof.

11. A method as in claim 1, wherein the step of disposing the monomer (16) in a carrier vehicle comprises disposing sufficient monomer in a carrier vehicle so that the substrate (10), when impregnated with the monomer mixture (14) will include approximately 0.1-10% by weight of monomer (16) thereupon.

12. A method as in claim 1, wherein the step of disposing the monomer (16) in a carrier vehicle comprises disposing the monomer (16) in a fluorocarbon vehicle.

13. A method as in claim 1, wherein the step of disposing the monomer (16) in a carrier vehicle comprises disposing the monomer (16) in a an aqueous emulsion of a non-aqueous solvent.

14. A method as in claim 9, wherein the step of providing a cross-linking reagent comprises providing an amount of cross-linking reagent which is equal by weight to up to 80% of said monomer mixture.

15. A method as in claim 9, wherein the step of providing a cross-linking reagent comprises providing an amount of cross-linking reagent which is equal by weight to up to 50% of said monomer mixture.

16. A method as in claim 1, wherein said substrate (10) is a polymeric substrate prepared from a polymer chosen from the group consisting essentially of:

polytetrafluoroethylene, vinyl, polyamide, polyurethane, polyvinylidene fluoride, polypropylene, polyethylene, polysulfone, poly(ethersulfone) and combinations thereof.

17. A method as in claim 1, wherein said substrate (10) is prepared from a material chosen from the group consisting essentially of:

woven fabric, knitted fabric, non-woven fabric, paper, leather and combinations thereof.