Filter media

• US 7,138,057 B2
• Filed: 07/22/2004
• Issued: 11/21/2006
• Est. Priority Date: 07/22/2004
• Status: Active Grant

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: Gore Enterprise Holdings Incorporated
• Inventors: Gebert, Richard E., Debes, Michael H.
• Primary Examiner(s): FORTUNA, ANA M
• Application Number:
  US10/896,770
• Publication Number:
  US 20060016749A1
• Time in Patent Office: 852 Days
• Field of Search: 210/490, 210/484, 210/488, 210/500.36, 210/506, 210/508, 210/500.29, 156/60, 156/297, 156/307.7, 156/308.2, 156/321, 428/153, 428/537.5, 162/164.5, 162/164.6, 162/164.7, 162/165, 162/84, 554/86, 555/87, 553/82
• US Class Current: 210/500.36
• CPC Class Codes: B01D 39/1692 Other shaped material, e.g. perforated or porous sheets
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14

Abstract

In one aspect, the invention provides an article consisting essentially of a paper layer including about 10 Wt % to about 40 Wt % of a thermoplastic polymer and an ePTFE membrane laminated to the paper layer. Preferably, the paper layer includes about 10 Wt % to about 30 Wt % of a thermoplastic polymer. More preferably, the paper layer includes about 18 Wt % to about 25 Wt % of a thermoplastic polymer. A paper layer including about 20 Wt % of a thermoplastic polymer is most preferred. In another aspect, the thermoplastic polymer may comprise poly vinyl acetate. In yet another aspect, the invention provides a filter media consisting essentially of a cellulose paper layer including about 20 Wt % poly vinyl acetate binder; and an ePTFE membrane laminated to said cellulose paper layer. In still another aspect, the invention provides a paper layer in which the paper is cellulose paper. In yet another aspect, the invention provides a method of making a filter media consisting essentially of: providing a cellulose paper layer including about 20 Wt % of poly vinyl acetate, providing an ePTFE membrane to at least one surface of the cellulose paper layer; and laminating the ePTFE membrane to the cellulose paper layer.

Claims

1. An article consisting essentially of:

a) a paper layer consisting of cellulose fibers and about 10 Wt % to about 40 Wt % of a thermoplastic binder wherein the binder is polyvinyl acetate, and

b) a hydrophobic ePTFE membrane laminated to the paper layer.

2. The article of claim 1 in which the paper layer includes about 10 Wt % to about 30 Wt % of the thermoplastic binder.

3. The article of claim 1 in which the paper layer includes about 18 Wt % to about 25 Wt % of the thermoplastic binder.

4. The article of claim 1 in which the paper layer includes about 20 Wt % of the thermoplastic binder.

5. A filter media consisting essentially of:

a) a cellulose paper layer consisting of cellulose fibers and about 20 Wt % poly vinyl acetate binder, the cellulose paper layer having an upstream side and a downstream side relative to the direction of airflow; and

b) a hydrophobic ePTFE membrane laminated to the upstream side of said cellulose paper layer.

6. A method of making a filter media consisting essentially at

a) providing a cellulose paper layer consisting essentially of cellulose fibers and about 20 Wt % of poly vinyl acetate binder,

b) providing a hydrophobic ePTFE membrane to at least one surface of the cellulose paper layer;

and

c) laminating the ePTFE membrane to the cellulose paper layer such that the ePTFE membrane adheres to the cellulose paper layer by melting at least a portion of the poly vinyl acetate binder.