High temperature treated media
AssigneeDonaldson Company, Inc.
InventorsDaniel Little, Robert M. Rogers
Life of this patent
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Abstract
A thermally bonded filtration media that can be used in high temperature conditions in the absence of any loss of fiber through thermal effects or mechanical impact on the fiber components is disclosed. The filter media can be manufactured and used in a filter unit or structure, can be placed in a stream of removable fluid, and can remove a particulate load from the mobile stream at an increased temperature range. The combination of bi-component fiber, other filter media fiber, and other filtration additives provides an improved filtration media having unique properties in high temperature, high performance applications.
Claims35
A nonwoven web comprising fibers in a thermally bonded web, the web comprising:
- (a) a bi-component fiber having a structural polymer portion and a thermoplastic binder polymer portion, the binder polymer having a melting point of greater than 115° C.;
- the bi-component fiber having a diameter of about 5 to 25 μm and a length of about 2 to 15 mm;
- and
- (b) a staple fiber;
- wherein the web is substantially free of glass fiber.
A nonwoven web comprising fibers in a thermally bonded web, the web comprising:
- (a) about 1 to 30 wt. %, based on the weight of the web, of a bi-component fiber having a core polymer and a shell polymer, wherein the core polymer has a melting point of at least 240° C. and the shell polymer has a melting point of up to 115° C.;
- and the bi-component fiber has a diameter of about 5 to about 25 μm and a length of about 2 to about 15 mm;
- (b) about 5 to 50 wt. %, based on the weight of the web, of a bi-component fiber having a core polymer and a shell polymer, wherein the core polymer has a melting point of at least 240° C. and the shell polymer has a melting point of 120° to 170° C.;
- and the bi-component fiber has a diameter of about 5 to about 25 microns and a length of about 2 to about 15 mm;
- and
- (c) about 10 to 80 wt. %, based on the weight of the web of a staple fiber;
- wherein the web has a thickness of about 0.25 to about 2 mm, a solidity of about 5 to about 10%, a basis weight of about 45 to about 150 grams per square meter, a pore size of about 12 to about 50 microns, and a permeability of about 1.5 to about 3 msec.
A nonwoven web comprising fibers in a thermally bonded sheet, the sheet substantially free of a glass fiber, the web comprising:
- (a) about 1 to about 15 wt. % of a bi-component fiber having a first core polymer with a melting point of 240° to 260° C. and a shell polymer with a melting point of 100° to 115° C.;
- wherein the bi-component fiber has a diameter of about 10 to about 15 μm and a length of about 0.3 to 0.9 cm;
- (b) about 5 to about 50 wt. % of a bi-component fiber having a core polymer with a melting point of 240° to 260° C. and a shell polymer with a melting point of 120° to 160° C.;
- wherein the bi-component fiber has a diameter of about 10 to 15 microns and a length of about 0.3 to 0.9 centimeters;
- (c) a cotton linter fiber;
- and
- (d) a polyester fiber.
A method of making a nonwoven web comprising a thermally bonded web, the method comprising:
- (a) forming a furnish comprising an aqueous concentration of solids of about 0.005 to about 5 wt. %;
- the solids comprising about 20 to about 60 wt. % of a bi-component fiber;
- about 5 to about 25 wt. % of a staple fiber comprising a cotton linter fiber;
- and the cotton fiber having a diameter of less than about 80 μm and a fiber length of less than about 4 mm;
- (b) contacting the furnish with an inclined screen to form a wet layer;
- and
- (c) forming a web from the wet layer.
An aqueous furnish suitable to form a nonwoven web comprising a thermally bonded sheet comprising an aqueous medium comprising:
- (a) about 1 to 30 wt. % of a first bi-component fiber having a core polymer and a shell polymer with a melting point of up to 115° C.;
- and a diameter of about 13 μm in the fiber length of about 0.6 cm;
- (b) about 20 to 50 wt. % of a second bi-component fiber having a core polymer and a shell polymer with a melting point of 115 to 170° C.;
- and having a fiber diameter of about 13 microns and a fiber length of about 0.6 centimeters;
- (c) about 20 to 50 wt.-% of a staple non-bicomponent polyester fiber having a fiber diameter of about 10 microns and a fiber length of about 0.6 centimeters having a melting point of greater than about 250 degrees centigrade;
- (d) about 7.5 wt.-% of a staple cellulosic fiber having a fiber diameter of about 29 microns and a fiber length of about 0.3 centimeters;
- and
- (e) the web comprising a treatment on the fibers of about 0.5 to 5 wt.-% of a C2-6 fluorochemical;
- Wherein wt. % are based on solids content and the web has a thickness of about 0.7 millimeters, a solidity of about 8 percent, a basis weight of about 65 g-m−2 a pore size of about 30 microns and a permeability of 2 meters per second.
A method of making a nonwoven web comprising a thermally bonded sheet, the sheet substantially free of a glass fiber, the method comprising, in an inclined wire papermaking machine:
- (i) forming an aqueous furnish having a concentration of solids of about 0.005 to 5 wt. % comprising:
- (a) about 20 to 70 wt-% of a bicomponent fiber having a fiber diameter of about 13 μm in the fiber length of about 0.6 cm;
- (b) about 30 to 70 wt-% of a staple fiber comprising a polyester fiber, a cellulosic fiber or a combination of both, the fiber having a diameter of about 10 microns and the fiber length of about 0.6 cm;
- and
- (ii) forming a layer from the furnish by removing water;
- and
- (iii) treating the layer with about 2 wt-% of a C2-7 fluorochemical treatment;
Dependencies are inferred from the claim text.