# US 5,350,620 A · Filtration media comprising non-charged meltblown fibers and electrically charged staple fibers

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- Number: US 5,350,620 A
- Document ID: US5350620A
- Status: Granted
- Kind: A
- Application number: 07/824,994
- Filed: 1992-01-24
- Granted: 1994-09-27
- Earliest claimed: 1989-11-14
- Assignees: Minnesota Mining and Manufacturing Company
- Inventors: Douglas C. Sundet; Albert H. Fox
- Web page: https://patentgrep.com/patent/US5350620A

## CPC

- B01D 39/2017: {the material being filamentary or fibrous}
- B01D 39/1623: {of synthetic origin}
- D04H 1/42: characterised by the use of certain kinds of fibres insofar as this use has no preponderant influence on the consolidation of the fleece
- D04H 1/56: in association with fibre formation, e.g. immediately following extrusion of staple fibres
- B01D 2239/10: Filtering material manufacturing
- Y10S 55/39: Electrets separator
- Y10S 428/903: Microfiber, less than 100 micron diameter
- Y10T 428/24612: Composite web or sheet
- Y10T 428/24686: Pleats or otherwise parallel adjacent folds
- Y10T 428/2495: Thickness [relative or absolute]
- Y10T 428/2904: Staple length fiber
- Y10T 442/619: Including other strand or fiber material in the same layer not specified as having microdimensions
- B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28)
- D04H: MAKING TEXTILE FABRICS, e.g. FROM FIBRES OR FILAMENTARY MATERIAL (weaving D03; knitting D04B; braiding D04C; net-making D04G; sewing D05B; tufting D05C; finishing non-woven fabrics D06); FABRICS MADE BY SUCH PROCESSES OR APPARATUS, e.g. FELTS, NON-WOVEN FABRICS; COTTON-WOOL; WADDING {; NON-WOVEN FABRICS FROM STAPLE FIBRES, FILAMENTS OR YARNS, BONDED WITH AT LEAST ONE WEB-LIKE MATERIAL DURING THEIR CONSOLIDATION}(non-woven fabrics having an intermediate or external layer of a different kind, e.g. of woven fabric, B32B)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Filtration material comprising a web comprising meltblown fibers and staple, electrically charged fibers randomly dispersed among the meltblown fibers. The filtration material can be formed in planar configurations and in configurations other than planar. Non-planar configurations can extend the useful working area for a given filter element's cross-section without requiring an additional corrugating or pleating process step. The filtration material exhibits high strength and low pressure drop.

## Claims

### Claim 1

A web comprising:
(a) a mass of meltblown, non-charged fibers made of polymeric material; and
(b) staple, electrically charged fibers randomly dispersed among the meltblown fibers, wherein the pressure drop through the web is less than about 74.7 pascals (Pa) at 0.91 m/sec air velocity and the value of Quality Factor (Q) is from at least about 0.05 Pa.sup.-1 to about 5.0 Pa.sup.-1, said web having a weight of from 40 g/m.sup.2 to 150 g/m.sup.2.

### Claim 2 (depends on 1)

The web of claim 1, wherein the concentration of said electrically charged staple fibers range from about 10% by weight to about 80% by weight of the web.

### Claim 3 (depends on 1)

The web of claim 1, wherein the average diameter of said meltblown fibers is from about 0.1 micrometer to about 50 micrometers.

### Claim 4 (depends on 3)

The web of claim 3, wherein the average diameter of said meltblown fibers is at least about micrometers.

### Claim 5 (depends on 1)

The web of claim 1, wherein the average length-to-diameter ratio of said meltblown fibers is at least about 5000:1.

### Claim 6 (depends on 1)

The web of claim 1, wherein the average length of the staple, electrically charged fibers is from about 6.5 mm to about 50 mm.

### Claim 7 (depends on 1)

The web of claim 1, wherein at least a portion of said electrically charged fibers contain a positive charge only.

### Claim 8 (depends on 1)

The web of claim 1, wherein at least a portion of said electrically charged fibers contain a negative charge only.

### Claim 9 (depends on 1)

The web of claim 1, wherein at least a portion of said electrically charged fibers have a permanent state of electric polarization.

### Claim 10 (depends on 1)

The web of claim 1, wherein the meltblown fibers are made from a polymeric material selected from the group consisting of polyolefins, polyesters, polyurethanes, and mixtures thereof.

### Claim 11 (depends on 10)

The web of claim 10, wherein the meltblown polymeric fibers are made of polypropylene.

### Claim 12 (depends on 1)

The web of claim 1, wherein the value of Quality Factor (Q) is at least about 0.1 Pa.sup.-1.

### Claim 13 (depends on 1)

The web of claim 1, wherein said web comprises a plurality of pillowed regions spaced from one another by planar regions, said pillowed regions displaced to one side of said planar regions.

### Claim 14 (depends on 1)

The web of claim 1, wherein said web comprises a plurality of pleats running transversely across said web.