# US 12,109,520 B2 · Multi-layer, biodegradable composites for air filtration

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- Number: US 12,109,520 B2
- Document ID: US12109520B2
- Status: Granted
- Kind: B2
- Application number: 17/422,560
- Filed: 2020-01-17
- Published: 2022-03-31
- Granted: 2024-10-08
- Earliest claimed: 2019-01-21
- Assignees: 3M Innovative Properties Company
- Applicants: 3M Innovative Properties Company
- Inventors: Zhiqun Zhang; Michael R. Berrigan; Ignatius A. Kadoma; Bryan L. Gerhardt; Liming Song; John D. Stelter; Zackary J. Becker
- Web page: https://patentgrep.com/patent/US12109520B2

## CPC

- B01D 39/163: {sintered or bonded}
- B01D 46/10: Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
- B01D 46/521: {using folded, pleated material}
- B32B 5/022: {Non-woven fabric}
- B32B 5/06: characterised by a fibrous {or filamentary} layer {mechanically connected, e.g. by needling} to another layer, e.g. of fibres, of paper
- B32B 5/08: the fibres or filaments of a layer being of different substances {, e.g. conjugate fibres, mixture of different fibres}
- B32B 5/26: another layer {next to it} also being fibrous or filamentary {(relative arrangement of fibres or filaments of different layers B32B5/12)}
- B32B 5/267: {characterised by at least one non-woven fabric layer that is a spunbonded fabric}
- B32B 7/12: using interposed adhesives or interposed materials with bonding properties
- D01F 1/10: Other agents for modifying properties
- D01F 8/14: with at least one polyester as constituent
- D04H 1/5412: {sheath-core}
- D04H 3/011: Polyesters
- D04H 3/16: with bonds between thermoplastic filaments produced in association with filament formation, e.g. immediately following extrusion
- F24F 8/108: using dry filter elements
- B01D 2239/0216: Bicomponent or multicomponent fibres
- B01D 2239/0233: Island-in-sea
- B01D 2239/0266: comprising biodegradable or bio-soluble polymers
- B01D 2239/0618: Non-woven
- B01D 2239/0627: Spun-bonded
- B01D 2239/065: More than one layer present in the filtering material
- B01D 2239/10: Filtering material manufacturing
- B01D 2239/1291: Other parameters
- B32B 2250/02: 2 layers
- B32B 2250/20: All layers being fibrous or filamentary
- B32B 2262/0253: Polyolefin fibres
- B32B 2262/0261: Polyamide fibres
- B32B 2262/0276: Polyester fibres
- B32B 2262/12: Conjugate fibres, e.g. core/sheath or side-by-side
- B32B 2262/124: Non-woven fabric
- B32B 2307/7163: Biodegradable
- B32B 2307/718: Weight, e.g. weight per square meter
- B32B 2307/724: Permeability to gases, adsorption
- B32B 2307/734: Dimensional stability
- B32B 2607/00: Walls, panels
- D01D 5/0985: {by means of a flowing gas (e.g. melt-blowing)}
- D10B 2331/041: derived from hydroxy-carboxylic acids, e.g. lactones
- D10B 2401/041: thermoplastic; thermosetting
- D10B 2401/12: biodegradable
- D10B 2505/04: Filters
- 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)
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- D01F: CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
- 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)
- F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02)
- D01D: MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
- D10B: INDEXING SCHEME ASSOCIATED WITH SUBLASSES OF SECTION D, RELATING TO TEXTILES

## Abstract

The present disclosure relates to multi-layer composite articles including at least two nonwoven web layers. Each or the layers may be a spunbonded web, and each may include biodegradable materials. The multi-layered composites of the present disclosure are particularly well suited for air filtration, as they can combine a high dust holding capacity with sufficient strength, dimensional stability, and a relatively low pressure drop.

## Claims

### Claim 1

A multi-layered composite comprising:
a first layer comprising a first nonwoven web, the web including multicomponent fibers; and
a second layer comprising a second nonwoven web adjacent the first layer, wherein the first layer has a Fiber Bundling Index of at least 2.

### Claim 2 (depends on 1)

The multi-layered composite of claim 1, wherein the multicomponent fibers include a first component that contains at least one high-melting point aliphatic polyester and a second component including a least one low-melting point aliphatic polyester.

### Claim 3 (depends on 2)

The multi-layered composite of claim 2, wherein the melting point of the low-melting point aliphatic polyester is at least about 20 degrees C. less than the melting point of the high-melting point aliphatic polyester.

### Claim 4 (depends on 1)

The multi-layered composite of claim 1, wherein the first nonwoven web is a spunbonded web.

### Claim 5 (depends on 1)

The multi-layered composite of claim 1, wherein the second nonwoven web is a spunbonded web.

### Claim 6 (depends on 1)

The multi-layered composite of claim 1, wherein the multicomponent fibers include one of:
a sheath comprising PBS and a core comprising PLA, and
a sheath comprising PLA and a core comprising PBS.

### Claim 7 (depends on 6)

The multi-layered composite of claim 6, wherein the fiber includes a sheath comprising PBS and a core comprising PLA, wherein the fiber includes between about 60-95 wt. % PLA and 5-40 wt. % PBS.

### Claim 8 (depends on 1)

The multi-layered composite of claim 1, wherein the composite is dimensionally stable.

### Claim 9 (depends on 7)

The multi-layered composite of claim 7, wherein the composite does not include polypropylene stabilizing agents.

### Claim 10 (depends on 1)

The multi-layered composite of claim 1, wherein the second nonwoven web includes monocomponent fibers or bicomponent fibers.

### Claim 11 (depends on 10)

The multi-layered composite of claim 10, wherein the monocomponent fibers or bicomponent fibers include PLA.

### Claim 12 (depends on 1)

The multi-layered composite of claim 1, wherein the first nonwoven layer has a Fiber Bundling Index of at least 2.

### Claim 13

A flat panel air filter or pleated air filter comprising a multi-layered composite, the composite comprising:
a first layer comprising a first spunbonded web, the web including bicomponent fibers; and
a second layer comprising a second spunbonded web affixed to the first layer,
wherein the bicomponent fibers include a sheath comprising one of PBS, or a PBS/PLA blend,
wherein the biocomponent fibers include a core comprising PLA,
wherein the second spunbonded web includes PLA,
wherein the composite lacks at least one of a viscosity modifier and a polypropylene stabilizing additive.

### Claim 14 (depends on 13)

The air filter of claim 13, wherein the filter has a Dust Holding Capacity of at least 40.

### Claim 15 (depends on 14)

The air filter of claim 14, wherein the filter has a Dust Holding Capacity of at least 50.

### Claim 16 (depends on 13)

The air filter of claim 13 and demonstrating a pressure drop of no greater than 0.15 mmH2O.

### Claim 17 (depends on 13)

The air filter of claim 13, wherein the filter is biodegradable.

### Claim 18

A multi-layered composite comprising:
a first layer comprising a first spunbonded web, the web including bicomponent fibers; and
a second layer comprising a second spunbonded web affixed to the first layer and including bicomponent fibers, wherein the bicomponent fibers in each web include a sheath comprising one of PBS or a PBS/PLA blend, and a core comprising PLA.

### Claim 19 (depends on 18)

The multi-layered composite of claim 18, wherein the bicomponent fibers in at least the first web include a nucleating agent.