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WO2022035607A1 - Face masks incorporating elastomeric layers and methods of producing such face masks - Google Patents

Face masks incorporating elastomeric layers and methods of producing such face masks Download PDF

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Publication number
WO2022035607A1
WO2022035607A1 PCT/US2021/043671 US2021043671W WO2022035607A1 WO 2022035607 A1 WO2022035607 A1 WO 2022035607A1 US 2021043671 W US2021043671 W US 2021043671W WO 2022035607 A1 WO2022035607 A1 WO 2022035607A1
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WO
WIPO (PCT)
Prior art keywords
layer
mask
layers
previous
inner face
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2021/043671
Other languages
French (fr)
Inventor
John M. DONAHUE
Abigail I. AGENTIS
Scott P. Wilkins
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ExxonMobil Chemical Patents Inc
Original Assignee
ExxonMobil Chemical Patents Inc
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Filing date
Publication date
Application filed by ExxonMobil Chemical Patents Inc filed Critical ExxonMobil Chemical Patents Inc
Publication of WO2022035607A1 publication Critical patent/WO2022035607A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1607Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
    • B01D39/1623Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
    • AHUMAN NECESSITIES
    • A41WEARING APPAREL
    • A41DOUTERWEAR; PROTECTIVE GARMENTS; ACCESSORIES
    • A41D13/00Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches
    • A41D13/05Professional, industrial or sporting protective garments, e.g. surgeons' gowns or garments protecting against blows or punches protecting only a particular body part
    • A41D13/11Protective face masks, e.g. for surgical use, or for use in foul atmospheres
    • A41D13/1107Protective face masks, e.g. for surgical use, or for use in foul atmospheres characterised by their shape
    • AHUMAN NECESSITIES
    • A62LIFE-SAVING; FIRE-FIGHTING
    • A62BDEVICES, APPARATUS OR METHODS FOR LIFE-SAVING
    • A62B23/00Filters for breathing-protection purposes
    • A62B23/02Filters for breathing-protection purposes for respirators
    • A62B23/025Filters for breathing-protection purposes for respirators the filter having substantially the shape of a mask
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D39/00Filtering material for liquid or gaseous fluids
    • B01D39/14Other self-supporting filtering material ; Other filtering material
    • B01D39/16Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
    • B01D39/1692Other shaped material, e.g. perforated or porous sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/04Additives and treatments of the filtering material
    • B01D2239/0435Electret
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604Arrangement of the fibres in the filtering material
    • B01D2239/0622Melt-blown
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/0604Arrangement of the fibres in the filtering material
    • B01D2239/0627Spun-bonded
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065More than one layer present in the filtering material
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/06Filter cloth, e.g. knitted, woven non-woven; self-supported material
    • B01D2239/065More than one layer present in the filtering material
    • B01D2239/0677More than one layer present in the filtering material by spot-welding
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D2239/00Aspects relating to filtering material for liquid or gaseous fluids
    • B01D2239/10Filtering material manufacturing

Definitions

  • the present invention relates in general to face masks, and in particular to elastomeric face masks that are soft, stretchable, recyclable and capable of rapid commercial production.
  • polypropylene is a polymer of propylene-derived units and can be made by known polymerization means.
  • Common methods used to make fibers and fabrics are described in US 9,168,720, US 9,194,060, US 9,322,114, and US 10,428,443.
  • Two common types of nonwoven fabrics are described as being ‘spunbond’ or ‘meltblown’, depending on the process used to make them.
  • these fabrics can be variously layered and bound to one another to form articles such as surgical gowns, surgical masks, dust and other protective face masks, and other types of disposable, protective clothing and covering.
  • a unique face mask and method of making a mask a mask that is made mostly or entirely from nonwoven materials such as nonwoven polypropylene.
  • These masks will incorporate elastomeric polyolefins, especially propylene-based elastomers such as VistamaxxTM propylene-based elastomers.
  • propylene-based elastomers such as VistamaxxTM propylene-based elastomers.
  • These polymers can be easily spun or blown into nonwoven materials and layered with polypropylene homopolymer or copolymer materials, and/or formed into elastic zones within or upon the nonwoven fabrics made from the polypropylene. They are soft, extensible, and completely recyclable.
  • a mask comprising (or consisting of, or consisting essentially of) one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask.
  • a mask comprising (or consisting of, or consisting essentially of) one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer.
  • Also disclosed is a method of forming a mask comprising (or consisting of, or consisting essentially of) feeding at least three layers of nonwoven polyolefin, an inner face layer and an outer visible layer to envelop at least one middle layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer resides unattached.
  • FIG. 1 represents a top view of an embodiment of the mask, wherein the lower rectangle is an elastic spunbond inner face layer, preferably perforated to aid breathability, and may be cut to only cover the meltblown middle layer to save material, but cut wide enough to allow attachment to the outer visible layer;
  • the lower rectangle is an elastic spunbond inner face layer, preferably perforated to aid breathability, and may be cut to only cover the meltblown middle layer to save material, but cut wide enough to allow attachment to the outer visible layer;
  • FIG. 2 represents a top view of one method of bonding the layers together, in this case a point-bond (dark gray dots) in various points, to bond the inner layer (spunbond or SB) to the outer layer.
  • the middle meltblown layer may or may not be part of the bond, as it can either move freely between the spunbond layers or be fixed therein, preferably free to allow for stretchability;
  • FIG. 3 represents a top view of an embodiment of how die cuts might look as the layered material continues to move in the machine direction (MD) in a commercial production cycle, where the parts are die cut across the MD;
  • FIG. 4 represents an exemplary cut mask, showing the breathable portion that would fit over the users mouth and nose, and the tie portion which would be used to fasten the mask to the users face by wrapping around the head;
  • FIG. 5 represents another embodiment of a cut mask, demonstrating at least one ear slit on each end of the bands formed from the inner and outer layers of nonwoven polyolefins;
  • FIG. 6 represents another embodiment of a cut mask, demonstrating at least two ear slits on each end of the bands formed from the inner and outer layers of nonwoven polyolefins;
  • FIG. 7 represents an edge cut-away view of a multilayered laminate forming a mask, the laminate on the left a three-layered configuration, and the one or the right a four- layer configuration comprising a high loft material (“open construction NW”).
  • Preferred masks will comprise at least two spunbond fabric layers with at least one meltblown polypropylene fabric layer sandwiched there between.
  • a high loft non wo ven fabric such as an air laid polypropylene high loft fabric (1 or 2 mm to 6 or 10 mm thickness) may also be sandwiched between the spunbond fabric layers and on the face side of the melt blown layer.
  • the meltblown layer can be made from, for example, polypropylene homopolymer and positioned so that there is a perimeter of spunbond primarily consisting of propylene-based elastomer around it.
  • the spunbond top and bottom layers can be made from, for example, polypropylene blended with one or more propylene-based elastomers.
  • these layers can be heat sealed together and/or ultrasonic bonded.
  • the whole structure may be then heat bonded such as at 125°C, or some temperature less than the melting point temperature of the meltblown polypropylene but greater than the melting point temperature of the spunbond propylene-based elastomer layer or zone.
  • Masks and packages for the masks comprise (or consist of, or consist essentially of) of polyolefins such as polyethylene, polypropylene and propylene- based elastomer, preferably greater than 80, or 90, or 95 wt%, by weight of the materials, of polyolefins.
  • the packaging for such masks have two compartments “A” (or first) and “B” (or second).
  • the “A” compartment is for new, unused masks
  • the “B” compartment is for masks that have been worn and need to be recycled.
  • the package After all the masks from the original package have been used, the package, with “A” empty and “B” full, is placed into a recycling bin, or the package is printed with an address and pre-paid postage to act as a recycle mailing pouch.
  • the “A” and “B” compartments can be in one assembly with a partition, or made as two separate but connected compartments, and can optionally have a means to separate the two compartments such as by perforations between the two, or a means of folding one compartment into the other.
  • the masks and packaging can be recycled together.
  • a “polyolefin” is a polymer comprising a-olefin monomer units, preferably selected from ethylene, propylene, butene, hexene, and octene, most preferably selected from ethylene and propylene. Most preferably, the polyolefins will have a weight average molecular weight within a range from 40,000, or 50,000, or 80,000 g/mole to 100,000, or 400,000, or 500,000, or 600,000 g/mole as determined by gel permeation chromatography (GPC) for such polyolefins, such as disclosed at paragraphs [0051] to [0057] in WO 2018/226345. Polypropylene and propylene-based elastomers, defined further below, are preferred polyolefins.
  • a “polypropylene” is a polyolefin comprising at least 80, or 90, or 95, or 98 wt%, by weight of the polypropylene, of propylene derived units, and most preferably is a homopolymer of propylene derived units.
  • the melt flow rate (MFR) of the polypropylene can be within a range from 1, or 5, or 10, or 15, or 20, or 25 g/10 min to 45, or 55, or 100, or 300, or 350, or 400, or 450, or 500, or 1000, or 2000, or 2500 g/10 min, as measured per ASTM 1238, 2.16 kg at 230°C.
  • the polypropylene can form thermoplastic blends including from 1 wt% to 95 wt% by weight of the blend of the polypropylene, and is most preferably blended with a propylene-based elastomer.
  • the polypropylene is preferably crystalline, as evidenced by having a melting point temperature (Tm) greater than 110°C, greater than 115°C, and greater than 130°C, or within a range from 110, or 115, or 130°C to 150, or 160, or 170°C.
  • Tm melting point temperature
  • the term “crystalline,” as used herein characterizes those polymers which possess high degrees of inter- and intra-molecular order.
  • the polypropylene can have a heat of fusion at least 60 J/g, at least 70 J/g, or at least 80 J/g, as determined by Differential Scanning Calorimetry (DSC) analysis. The heat of fusion is dependent on the composition of the polypropylene.
  • a polypropylene homopolymer preferably has a higher heat of fusion than copolymer or blend of homopolymer and copolymer.
  • the thermal properties of the polypropylene and propylene- based elastomers were determined using DSC.
  • DSC data was obtained using a Perkin- Elmer DSC, where 7.5 mg to 10 mg of a sheet of the polymer to be tested was pressed at approximately 200°C to 230°C, then removed with a punch die and annealed at room temperature for 48 hours. The samples were then sealed in aluminum sample pans. The DSC data was recorded by first cooling the sample to -50°C and then gradually heating it to 200°C at a rate of 10°C/minute. The sample was kept at 200°C for 5 minutes before a second coolingheating cycle was applied. Both the first and second cycle thermal events were recorded.
  • a “propylene-based elastomer” is a polyolefin random copolymer having crystalline regions interrupted by non-crystalline regions and within the range from 5 to 25 wt%, by weight of the propylene-based elastomer, of ethylene or C4 to C10 a-olefin derived units, and optionally diene-derived units, the remainder of the polymer being propylene-derived units.
  • the propylene-based elastomers herein comprise from 5 to 25 wt%, by weight of the elastomer, of ethylene derived units, the remainder being propylene-derived units.
  • the propylene-based elastomer has an MFR within a range from 0.1, or 0.5, or 1 g/10 min to 5, or 10, or 20 g/10 min (ASTM 1238, 2.16 kg at 230°C).
  • the term “elastomer” refers to a polymer exhibiting some degree of elasticity, where elasticity is the ability of a material that has been deformed by a force (such as by stretching) to return at least partially to its original dimensions once the force has been removed. Not intended to be limited by any theory, it is believed that the non-crystalline regions may result from regions of non-crystallizable polypropylene segments and/or the inclusion of comonomer units. The crystallinity and the melting point of the propylene-based elastomer are reduced compared to highly isotactic polypropylene by the introduction of errors (stereo and region defects) in the insertion of propylene and/or by the presence of comonomer.
  • the propylene -based elastomer has a heat of fusion as determined by DSC of 75 J/g or less, 70 J/g or less, 50 J/g or less, or 35 J/g or less.
  • the propylene-based elastomer can have a lower limit heat of fusion of 0.5, 1, or 5 J/g.
  • the heat of fusion value may be within a range from 1.0, 1.5, 3.0, 4.0, 6.0, or 7.0 J/g, to 30, 35, 40, 50, 60, 70, or 75 J/g.
  • the heat of fusion of the polypropylene is higher than the heat of fusion of the propylene-based elastomer, preferably by at least 5 or 10 J/g-
  • the propylene-based elastomer has a melting point temperature (Tm) of 100°C or 90°C or less, or within a range from 30, or 40°C to 80, or 90, or 100°C.
  • Tm melting point temperature
  • the propylene-based elastomer can have a percent crystallinity, as determined according to the DSC of 2% to 65%, 0.5% to 40%, 1% to 30%, or 5% to 35%, of isotactic polypropylene.
  • the propylene-based elastomer has a crystallinity in the range of 0.25% to 25%, or 0.5% to 22% of isotactic polypropylene.
  • the polypropylene has a higher crystallinity than the propylene-based elastomer.
  • the propylene-based elastomers contain at least 60 wt% propylene-derived units by weight of the propylene-based elastomer.
  • the propylene-based elastomer can be a propylene-based elastomer having limited crystallinity due to adjacent isotactic propylene units and a melting point as described herein.
  • the propylene -based elastomer can be generally devoid of any substantial intermolecular heterogeneity in tacticity and comonomer composition, and also generally devoid of any substantial heterogeneity in intramolecular composition distribution.
  • the propylene-based elastomer can contain greater than 50 wt%, greater than 60 wt%, greater than 65 wt%, or greater than 75 wt% and up to 99 wt% propylene-derived units, based on the total weight of the propylene-based elastomer.
  • the propylene-based elastomer includes propylene-derived units in an amount based on the weight of propylene-based elastomer of from 75 wt% to 95 wt%, 75 wt% to 92.5 wt%, 82.5 wt% to 92.5 wt%, or 82.5 wt% to 90 wt%.
  • the units, or comonomers, derived from at least one of ethylene or a C4 to C10 a-olefin can be present in an amount of 5, or 10, or 14 wt% to 22, or 25 wt% by weight of the elastomer.
  • Commercial examples of such propylene-based elastomers include VistamaxxTM propylene-based elastomers from ExxonMobil Chemical Company, TafmerTM elastomers from Mitsui Chemicals, and VersifyTM elastomers from Dow Chemical Company.
  • meltblown fibers and fabrics refer to fibers formed by extruding a molten thermoplastic material at a certain processing temperature through a plurality of fine, usually circular, die capillaries as molten threads or filaments into high velocity, usually hot, gas streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web or nonwoven fabric of randomly dispersed meltblown fibers. Such a process is generally described in, for example, US 3,849,241 and US 6,268,203.
  • meltblown fibers are microfibers that are either continuous or discontinuous, and, depending on the resin, may have a diameter smaller than 10 microns (for example, for high MFR isotactic polypropylene resins such as AchieveTM 6936G2, available from ExxonMobil Chemical Company); whereas for certain resins (for example, VistamaxxTM propylene-based elastomer, available from ExxonMobil Chemical Company) or certain high throughput processes such as those described herein, meltblown fibers may have diameters greater than 10 microns, such as within a range from 10 to 30 microns, or 10 to 15 microns.
  • meltblowing as used herein is meant to encompass the meltspray process.
  • meltblown processes that utilize extrusion systems can have a relatively high throughput, in excess of 0.3 grams per hole per minute (“ghm”), or in excess of 0.4 ghm, or in excess of 0.5 ghm, or in excess of 0.6 ghm, or in excess of 0.7 ghm.
  • the nonwoven compositions can be produced using commercial meltblown processes, such as a high pressure meltblown process available from Biax-Fiberfilm Corporation, or in test or pilot scale processes.
  • the fibers used to form the nonwoven compositions can be formed using an extrusion system having a throughput rate within a range from 0.01 to 3.0 ghm, or from 0.1 to 2.0 ghm, or from 0.3 to 1.0 ghm.
  • meltblown fabrics used herein have a basis weight (grams per square meter) within a range from 20, or 25 gsm to 45, or 50, or 60, or 80 gsm.
  • spunbond fibers and fabrics refers to fibers and fabrics formed from polymer that is formed by first forming a melt to homogenize the polymers.
  • the extruder supplies melted polymer to a spinneret where the polymer is fiberized as passed through fine openings arranged in one or more rows in the spinneret, forming a curtain of filaments.
  • the filaments are usually quenched with air at a low temperature, drawn, usually pneumatically, and deposited on a moving mat, belt or “forming wire” to form the nonwoven composition.
  • spunbond as used herein is meant to include fabrics from spunlace processes, in which the filaments are entangled to form a web using highspeed jets of water (known as “hydroentanglement”).
  • the fibers produced in the spunbond process are usually in the range of from 10 to 50 microns in diameter, depending on process conditions and the desired end use for the fabrics to be produced from such fibers. For example, increasing the polymer molecular weight or decreasing the processing temperature results in larger diameter fibers. Changes in the quench air temperature and pneumatic draw pressure also have an effect on fiber diameter.
  • the spunbond fabrics used herein have a basis weight (grams per square meter) within a range from 50, or 60 gsm to 85, or 90, or 100, or 140 gsm.
  • the masks comprising the polyolefins described herein can be described as extensible.
  • “Extensible,” as used herein, means any fiber or nonwoven composition that yields or deforms (i.e., stretches) upon application of a force. While many extensible materials are also elastic, the term extensible also encompasses those materials that remain extended or deformed upon removal of the force. For instance, when an extensible facing layer is used in combination with an elastic core layer, desirable aesthetic properties may result because the extensible layer permanently deforms when the elastic layer to which it is attached stretches and retracts. This results in a wrinkled or textured outer surface with a soft feel that is particularly suited for articles in which the facing layer is in contact with a wearer's skin.
  • a “polyalphaolefin” are compositions that comprise oligomers of a-olefins and are often used as the base stock for synthetic lubricants.
  • PAO can be produced by the polymerization of a-olefins, such as linear a-olefins.
  • a PAO can be characterized as being unbranched, linear, atactic, or by any type of tacticity including isotactic or syndiotactic and/or atactic, and by any degree of tacticity, including isotactic -rich or syndiotactic -rich or fully atactic.
  • PAO liquids are described in, for example, US 3,149,178; US 4,827,064; US 4,827,073; US 5,171,908; and US 5,783,531; and in SYNTHETIC UUBRICANTS AND HIGH-PERFORMANCE FUNCTIONAL FLUIDS, 1-52 (Marcel Dekker, Ueslie R. Rudnick & Ronald U. Shubkin, eds. 1999).
  • PAOs are Group 4 compounds, as defined by the American Petroleum Institute (API).
  • the PAO can comprise C20 to C1500 paraffins, C40 to C1000 paraffins, C50 to C750 paraffins, or C50 to C500 paraffins.
  • the PAO can be dimers, trimers, tetramers, pentamers, etc.
  • Suitable olefins include 1 -pentene, 1 -hexene, 1 -heptene, 1 -octene, 1 -nonene, 1 -decene, 1 -undecene and 1-dodecene.
  • Exemplary PAO are described more particularly in, for example, US 5,171,908, and US 5,783,531; and also in SYNTHETIC LUBRICANTS AND HIGH-PERFORMANCE FUNCTIONAL FLUIDS.
  • PAO’ s can have a kinematic viscosity (KV) at 100 °C, as measured by ASTM D445 at 100 °C, of 3 cSt (1 cSt equals 1 mm 2 /s) to 3,000 cSt, 4 to 1,000 cSt, 6 to 300 cSt, 8 to 125 cSt, 8 to 100 cSt, or 10 to 60 cSt.
  • the PAO can have a KV at 100 °C of 5 to 1000 cSt, 6 to 300 cSt, 7 to 100 cSt, or 8 to 50 cSt.
  • PAO’s can also have a viscosity index (VI), as determined by ASTM D2270, of 50 to 400, or 60 to 350, or 70 to 250, or 80 to 200, or 90 to 175, or 100 to 150.
  • VI viscosity index
  • PAO can have a VI, as determined by ASTM D2270, of greater than 100, 110, 120, 150, or 200.
  • PAO is available from ExxonMobil Chemical Company, Houston, Texas under the trade name SpectraSyn.
  • Other useful PAO include those sold under the tradenames SynfluidTM available from ChevronPhillips Chemical Co. in Texas, DurasynTM available from BP Amoco Chemicals in London England, NexbaseTM available from Fortum Oil and Gas in Finland, SyntonTM available from Crompton Corporation in Middlebury Conn., USA, EmeryTM available from Cognis Corporation in Ohio.
  • Masks such as described herein are made on a machine line that assembles the non wo vens fabrics into laminates from bobbins, ultrasonically or heat welds the layers together, and stamps and cuts the laminates into desirable shapes, and in some embodiments stamps the masks with nose strips, ear loops, and other pieces.
  • Such laminates can be in the form of a sheet of material, or rolled into a roll (like a roll of paper towels as are sold commercially), or other convenient form.
  • the masks are formed from layered nonwoven fabrics thermally bonded by compressing it through a set of two heated rolls (calendars) for improving fabric integrity and improving fabric mechanical properties.
  • the calendar temperature is varied to create the bonding curve (i.e., tensile strength versus calendar temperature). Bonding temperatures can vary for the embossing roll from 140 to 155 °C and temperatures for the S-roll can vary from 135 to 155 °C.
  • Bonding temperatures can vary for the embossing roll from 140 to 155 °C and temperatures for the S-roll can vary from 135 to 155 °C.
  • the nonwoven fabrics described herein may be a single layer or may be multilayer laminates.
  • One application is to make a laminate from meltblown (“M”) and spunbond (“S”) nonwoven fabrics, which combines the advantages of strength from the spunbonded component and greater barrier properties of the meltblown component.
  • a typical laminate or laminate has three or more layers, a meltblown layer(s) sandwiched between two or more spunbonded layers, or “SMS” nonwoven laminates.
  • nonwoven polyolefin fabric or a “layer” of such nonwoven polyolefin fabric refers to a fabric formed from fibers of polyolefins (esp.
  • polypropylene and/or propylene-based elastomers spunbond or meltblown into a fabric, typically having some thickness from 0.1 to 2, or 3 mm in thickness and dimensions on the order of a meter in width and handled as a roll of the material that are unrolled in machinery designed to form articles from such fabric, and layered with one or more other fabrics to form layered laminates and shaped and cut into the article, such as the masks described herein.
  • the multilayered laminates are made with any number of rolls of spunbond and meltblown materials in their desirable configuration. Such rolls feed into the manufacturing equipment that allows for layering of the fabrics and bonding the layers as desired.
  • a typical spunbond fabric as a basis weight within a range from 10, or 15 gsm to 25, or 40, or 60, or 80, or 90 gsm which can be tailed by extruding the melted polyolefin onto a conveyor at a desired rate to form a web in which strands bond with each other as they cool.
  • the masks are made up of a multilayered laminate by covering a layer of meltblown fabric with non wo ven bonded fabric on both sides.
  • Nonwovens are inexpensive to make and clean due to their method of manufacture, and the materials used offers disposability.
  • These disposable masks can be made with more than one filter layers, preferably the meltblown layer, effective at filtering out particles above 1 micron.
  • the filtration level of a mask depends on the fiber, the way it is manufactured, the web’s structure, and the fiber’s cross-sectional shape. Completed masks are preferably sterilized before being sent out of the factory and worn.
  • any embodiment is a mask comprising one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask.
  • the mask takes on the structure of the base multilayered laminate used to make it, which comprises SMS in one embodiment, or SSMSS, or SSMMSS, or SMMS, or SSMMS, or SMSS, SSMSMSMS etc.
  • the “inner face layer” or “inner layer” is the one or more layers, preferably spunbond fabric, that is designed as part of the mask to contact the wearer’ s face and preferably of a size that would fit over at least the nose and chin (in width, MD direction) and at least across the cheeks of the wearer (in length, CD direction).
  • the “outer visible layer” or “outer layer” is the layer that faces away from the wearer, and is visible by others viewing the wearer.
  • the outer and inner layers do not need to be the same length in the CD direction.
  • One or the other layer preferably the inner layer, can define the overall shape of the mask and the bands on either side for fastening the mask to the wearer’s head, while the outer layer can be of any length so long as it is long enough to cover the middle layer and be attached to the inner layer such as to form a pocket or envelope for the middle layer.
  • Figures 1 to 4 demonstrate an embodiment wherein the outer layer is not coextensive with the inner layer.
  • the outer an inner layers can also be the same or similar such that they are coextensive in the CD direction. In any case, most preferably, the inner and outer layers are the same or similar width in the MD direction.
  • the masks disclosed herein are extensible. This is because the multilayered laminate from which they are made are extensible, wherein at least the inner and outer layers are preferably extensible either by the structure of the fabric itself, the polyolefins from which they are made, or both.
  • the inner and outer layers can be nonwoven materials made by any means, but preferably there is at least one inner face layer and at least one outer visible layer that are spunbond polypropylene.
  • the at least one middle layer is a meltblown polypropylene.
  • the at least one inner layer and at least one outer layer sandwiches the at least one middle layer there between, and that layer is free to move as it is not attached to any inner or outer layer. It is preferably sandwiched such that it presses against the inner and outer layers when the mask is stretched out across the wearer’ s face, but is otherwise not attached to any layer and free to move of float in the pocket created by the inner and outer layers.
  • at least the one meltblown layer is electrostatically charged, but any number of layers may also be electrostatically charged.
  • breathable portion located at least along a central portion of the inner and outer layers to facilitate air flow between the ambient air and the wearer’s nose and/or mouth, hence, the term “breathable portion”.
  • the polyolefin comprises (or consists essentially of) polypropylene and/or propylene-based elastomers comprising at least 60, or 70, or 80 wt%, by weight of the polypropylene or propylene -based elastomers, of propylene-derived units.
  • any layer of the mask can comprise (or consist essentially of) polypropylene, a propylene-based elastomer, or a blend of the two.
  • one or more of the inner face layer and outer visible layers comprises a propylene-based elastomer.
  • the mask further comprises a high loft nonwoven layer between the outer and inner layers, preferably on the face side of the middle layer.
  • a high loft fabric is EnkamatTM or PolartecTM high loft material (polyester or polyolefin 3-D matting composed of randomly laid monofilaments, also called “batting” or “wadding”), most preferably the polypropylene grade of high loft nonwoven, preferably composed of polypropylene staple fibers bonded with bicomponent fibers.
  • Such high loft layer may be bonded to the inner or outer layer, most preferably the inner layer prior to mask assembly; and may be bonded by a variety of methods including a polypropylene-based hot melt or ultrasonically.
  • the masks including the high loft layer may take a structure such as SLMS, SSLMS, SSLMSS, SLMMS, etc., wherein “L” is the high loft layer of material.
  • the mask if designed to fit snuggly against the face of the user and have a soft feel.
  • the mask can be made in various sizes to fit firmly against the skin of the wearer and expand and contract with the wearer’s facial movements.
  • the at least one of the inner face layer and/or outer visible layers forms a band, wherein each end can be fastened together by the wearer.
  • the at least one of the inner face layer and/or outer visible layers forms a band, wherein each band comprises one or more ear slits for fastening to the head of the wearer.
  • the outer and/or inner layers further comprise a polyalphaolefin; wherein the polyalphaolefin is present within a range from 1, or 2, or 5 wt% to 10, or 15 or 20 wt%, by weight of the polyolefin and polyalphaolefin.
  • the mask may further comprise polyolefin plugs, preferably soft foam plugs, attached to the inner face layer to contact the nose and cheeks of the wearer. Most preferably the plugs comprise polypropylene.
  • the bands can take any desirable form to facilitate attachment of the mask across the wearer’s face.
  • the bands can form a tie to be fastened around the head, or may have slits or cut-outs for each ear.
  • the mask comprises at least two layers of non wo ven polyolefin fabric, an inner face layer and an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer.
  • the masks are made only from polyolefins, most preferably from polypropylene and/or propylene-based elastomers, and thus adhesives and non-polyolefin materials are absent; preferably wherein the mask consists of polypropylene and/or propylene- based elastomers.
  • the masks made as described can be easily constructed by common multilayer laminate construction means, such as by feeding each layer from a roll of material down a line and laying each layer upon the other and attaching the layers as necessary to for the bands and breathable portion with the floating middle layer and optional high loft layer.
  • all of the layers of the mask are aligned such that the layers of nonwoven polyolefin (roll goods) may be fed and die cut in a manufacturing configuration allowing for at least 5,000, or 10,000 masks/hour to be produced.
  • the masks can be packaged (for transport and sale) in a tandem pouch having at least a first compartment and a second compartment, wherein one or more new, unused masks are in the first compartment and one or more used masks are placed in the second compartment.
  • the tandem pouch can then be dropped off at a recycle facility for complete recycling.
  • a method of forming a mask comprising feeding at least three layers of nonwoven polyolefin, an inner face layer and an outer visible layer, to envelope at least one middle layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer resides unattached.
  • FIG. 1 The masks described herein can be elucidated with reference to an embodiment shown in Figures 1 to 4, showing a perspective from above the layers of nonwoven fabric used to make the mask, and being formed in the machine direction from the rolls of fabric moving downward on the Figures.
  • an inner face layer 10 having a number perforations or holes 16 is provided, a section highlighted in shaded gray, with an outer visible layer 12 also having perforations or holes 16, sandwiching there between a middle nonwoven fabric layer (“middle layer”).
  • the inner and outer layers 10 and 12 are comprised of spunbond polyolefins, most preferably spunbond polypropylene, while the middle layer comprises a meltblown propylene-based elastomer.
  • one or more layers of a high loft material may also be sandwiched between the inner and outer layers 10 and 12.
  • a high loft material preferably high loft polypropylene
  • Such high loft may be fastened to the inner and/or outer layers, or float freely within an envelope or pocket made by the inner and outer layers 10 and 12.
  • the formed multilayered laminate 18 comprising at least the inner and outer layers 10 and 12, and middle layer 14, the multilayered laminate 18 having a band section 20 on each side of a breathable portion 24 located where the middle layer 14 is enveloped by the inner and outer layers 10 and 12, wherein heat bonds 22 are used to adhere the inner layer 10 to the outer layer 12 and allow the at least one middle layer 14 of meltblown fabric and optional high loft fabric to float freely within the envelope, not attached to any layer of fabric.
  • attachment of one fabric to another is typically accomplished using heat bonding such that the fabric layers are melted between one or more heated pressure points or lines (e.g., a platen or other heated element) and thus form a heat bonds to one another while in a molten or partially molten state.
  • heated pressure points or lines e.g., a platen or other heated element
  • additional adhesives are absent from such a multilayered laminate f8.
  • the multilayered laminate f8 continues to move down the line in the MD where it comes to a station/section for forming die cuts 26.
  • die cuts 26 can be of any number, shape, and complexity and are useful in forming individual sections, components, and ultimately, the masks themselves.
  • Figure 3 it can be seen that some die cuts 26 run across the entire CD of the multilayered laminate 18 and the breathable portion 24, while some other die cuts 26 only cut across a section of the band section 20.
  • FIG. 4 is a top view of a representative mask 28 having a band or tie portion 30 on each side of the breathable portion 32.
  • the wearer of the mask will then fit the mask across his/her face such that the breathable portion 32 fits over the nose and mouth and then wrap the tie portions 30 around the head and/or ears.
  • FIG. 5 Another embodiment of the masks described herein is represented in the top view drawing in Figure 5, wherein mask 34 comprises perforations or holes 36 in a breathable section and the cut away section 38 forms a ring that is useful to attach the mask 34 to the ears of the wearer.
  • the embodiment of the mask in Figure 6 shows a mask 40 comprising perforations or holes 42 in a breathable section while cut away sections 44 and 46 form alternative rings to attach the mask 40 to the ear of the wearer, the different sections 44 and 46 allowing for different size fits.
  • the cutaway sections 44 and 46 depicted in Figure 6 can also be slots cut into the fabric of the mask 40 on each side of the central section along the bands.
  • FIG. 7 A edge cut-away view through the top of a mask as it sits against a wearer’ s face is shown in Figure 7, wherein on the left is a three-layer mask demonstrating how air would flow between the ambient air (air external of the outer layer) and the wearer’s mouth and/or nose.
  • the drawing on the right demonstrates the effected of added air flow using a high loft fabric or batting, in this case between the inner layer and the middle layer.
  • the dotted lines represent the inner and outer layers, preferably spunbond fabrics.
  • the added high loft layer makes the effective breathable area of the mask larger by distributing air flow.
  • An exemplary mask could comprise at least two spunbond fabrics with at least one meltblown polypropylene layer sandwiched there between.
  • the meltblown layer can be made from, for example, polypropylene homopolymer such as AchieveTM Advanced PP6936G2, and positioned so that there is a perimeter of spunbond primarily consisting of propylene -based elastomer around it.
  • the meltblown middle layer is preferably 25 to 35 gsm.
  • the spunbond inner and outer layers can be made from, for example, ExxonMobilTM PP3155E5 polypropylene blended with VistamaxxTM 7050BF propylene-based elastomer.
  • the spunbond layers are preferably 75 to 85 gsm.
  • the blend may comprise at least 40, or 50, or 60, or 70, or 80 wt%, by weight of the blend, of propylene-based elastomer. These layers can be heat sealed together and/or ultrasonic bonded. After forming the layered structure, the whole structure may be then heat bonded such as at 125°C, or some temperature less than the melting point temperature of the meltblown polypropylene but greater than the melting point temperature of the spunbond propylene-based elastomer layer or zone.
  • the nonwoven layer roles can be unwound into an inner spunbond layer, middle meltblown layer, and outer spunbond layer of the laminate. Die cuts are made for the ear slits, and the spunbond layers are attached by applying ultrasonic bonding. Then in any embodiment a roll of film, a biaxially oriented polypropylene film most preferably, is unrolled onto the outer and inner sides of the laminate of masks. Next, a die cut of the rounded outer perimeter is made, and the center perimeters are perforated. The perforations are staggered to not allow any filaments to ‘bridge’. Finally, excess material is removed and the parts are wound onto a roll.
  • a die cut can be made through all three nonwoven layers of the laminate, then a biaxially oriented polypropylene roll can be unwound onto either the inner or outer spunbond layers (or both) of the laminate forming the mask.
  • a die cut of the rounded perimeter and the central sections where the nonwovens are cut through is made; at this point the laminate sheet is cut completely into separate masks but the biaxially oriented polypropylene film is continuous at three segments.
  • the biaxially oriented polypropylene sections are perforated.
  • the masks can then be separated by tearing the perforated biaxially oriented polypropylene sections.
  • the outer film layer will make handling the masks simpler.
  • the films can be attached by heat or be use of an adhesive.
  • the masks herein further comprise at least one layer of polypropylene film, preferably on the outside of either side of the mask, that is, on the “outside” portions that are touched by the users, the sides facing away from the at least one middle layer of the mask.
  • the film is preferably added to the laminate while it is being formed on the equipment that unrolls, layers and cuts the laminate into individual masks.
  • the structure in any embodiment is one of FSMS, FSMSF, FSSMSSF, etc., wherein “F” is a film.
  • Including the high loft material, the structure of the laminate forming the mask, or the mask itself, may take the form of FSLMS, FSLMSF, FSSLMSSF, FSLMMSF, FSLMMS, etc.
  • the side of the laminate that forms the inner layer will not have a film layer. Having the one layer of film can still facilitate the handling of the masks, or the attachment of the masks into the form of a roll that can then be easily tom away for individual use from the roll, much like an individual paper towel from a roll of paper towels.
  • a “film” is a thin flexible material that is continuous (not porous) and is within a range from 20, or 50 pm to 250, or 300, or 400 pm in average thickness, preferably made by blowing or casting molten polyolefin, preferably polypropylene, into the thin film. It is most preferably biaxially oriented, meaning that while being formed it has been stretched in the MD and CD such that the polymer molecules have been allowed a degree of orientation.
  • the film is extensible, and most preferably is extensible and elastic.
  • the invention described herein includes a laminate roll comprising (or consisting of, or consisting essentially of) multiple masks comprising one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer sandwiched between the inner face layer and outer visible layer, the at least three fabric layers of an inner face layer, a middle layer, and an outer visible layer forming a laminate; at least one layer of a film on at least the outer visible layer of the laminate roll to form a tearable laminate, wherein the laminate is cut (scored or perforated) into individual masks to allow individual masks to be tom away from one another from the sheet or roll of laminate; and wherein the tearable laminate is in the form of a roll.
  • a “cut” may comprise a score or series of perforations (such as made by a die cutter or blade) in the material that can allow the components or parts on either side of the score to be torn from one another, but a die cut can also result in a score or perforations that results in the material components or parts to sever from one another without any further force.
  • the inner face layer and outer visible layers in the laminate roll are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask.
  • each band comprises at least one ear slit for fastening to the head of the wearer.
  • the phrase “consisting essentially of’ for the masks and the polyolefins that make up the masks means that there may be up to 1, or 2, or 3, or 4 wt%, by weight of the polyolefins, of additives such as antioxidants, cross-linking agents, peroxides and other visbreaking agents, alkyl radical scavengers, acid neutralizers, nucleating agents, fillers, colorants, polymeric compatibilizers (other elastomers, plastomers, LDPE, etc.), hydrocarbon resins, and/or other such additives as are known in the art.
  • additives such as antioxidants, cross-linking agents, peroxides and other visbreaking agents, alkyl radical scavengers, acid neutralizers, nucleating agents, fillers, colorants, polymeric compatibilizers (other elastomers, plastomers, LDPE, etc.), hydrocarbon resins, and/or other such additives as are known in the art.

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Abstract

A mask comprising one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein in one embodiment the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask. Also, a method of forming a mask comprising feeding at least three layers of nonwoven polyolefin forming an inner face layer and an outer visible layer which envelope at least one middle layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer resides unattached.

Description

FACE MASKS INCORPORATING ELASTOMERIC LAYERS AND METHODS OF PRODUCING SUCH FACE MASKS
CROSS-REFERENCE OF RELATED APPLICATION
[0001] This application claims priority to and the benefit of USSN 63/064,208, filed August 11 , 2020, the disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates in general to face masks, and in particular to elastomeric face masks that are soft, stretchable, recyclable and capable of rapid commercial production.
BACKGROUND
[0003] It is known to make fibers and fabrics from polyolefins, especially polypropylene. Polypropylene is a polymer of propylene-derived units and can be made by known polymerization means. Common methods used to make fibers and fabrics are described in US 9,168,720, US 9,194,060, US 9,322,114, and US 10,428,443. Two common types of nonwoven fabrics are described as being ‘spunbond’ or ‘meltblown’, depending on the process used to make them. Preferably, these fabrics can be variously layered and bound to one another to form articles such as surgical gowns, surgical masks, dust and other protective face masks, and other types of disposable, protective clothing and covering.
[0004] What is disclosed here is a unique face mask and method of making a mask, a mask that is made mostly or entirely from nonwoven materials such as nonwoven polypropylene. These masks will incorporate elastomeric polyolefins, especially propylene-based elastomers such as Vistamaxx™ propylene-based elastomers. These polymers can be easily spun or blown into nonwoven materials and layered with polypropylene homopolymer or copolymer materials, and/or formed into elastic zones within or upon the nonwoven fabrics made from the polypropylene. They are soft, extensible, and completely recyclable.
[0005] Relevant publications include: “Facial Masks Incorporating Elastomeric and Rigid Polyolefins,” published June 18, 2020 on IP.com (IPCOM000262668D); “Recycleable Protective Masks Incorporating Elastomerics and Packaging Thereof,” published May 1, 2020 on IP.com (IPCOM000262121D); “Methods of Producing Protective Face Masks Incorporating Elastomeric Layers and/or Elastic Zones,” published April 24, 2020 on IP.com (IPCOM000262003D); and “Facial Masks Incorporating Elastomeric Layers and/or Elastic Zones,” published April 13, 2020 on IP.com (IPCOM000261858D). SUMMARY
[0006] Disclosed is a mask comprising (or consisting of, or consisting essentially of) one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask.
[0007] Also disclosed is a mask comprising (or consisting of, or consisting essentially of) one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer.
[0008] Also disclosed is a method of forming a mask comprising (or consisting of, or consisting essentially of) feeding at least three layers of nonwoven polyolefin, an inner face layer and an outer visible layer to envelop at least one middle layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer resides unattached.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 represents a top view of an embodiment of the mask, wherein the lower rectangle is an elastic spunbond inner face layer, preferably perforated to aid breathability, and may be cut to only cover the meltblown middle layer to save material, but cut wide enough to allow attachment to the outer visible layer;
[0010] FIG. 2 represents a top view of one method of bonding the layers together, in this case a point-bond (dark gray dots) in various points, to bond the inner layer (spunbond or SB) to the outer layer. The middle meltblown layer may or may not be part of the bond, as it can either move freely between the spunbond layers or be fixed therein, preferably free to allow for stretchability;
[0011] FIG. 3 represents a top view of an embodiment of how die cuts might look as the layered material continues to move in the machine direction (MD) in a commercial production cycle, where the parts are die cut across the MD; [0012] FIG. 4 represents an exemplary cut mask, showing the breathable portion that would fit over the users mouth and nose, and the tie portion which would be used to fasten the mask to the users face by wrapping around the head;
[0013] FIG. 5 represents another embodiment of a cut mask, demonstrating at least one ear slit on each end of the bands formed from the inner and outer layers of nonwoven polyolefins; [0014] FIG. 6 represents another embodiment of a cut mask, demonstrating at least two ear slits on each end of the bands formed from the inner and outer layers of nonwoven polyolefins; and
[0015] FIG. 7 represents an edge cut-away view of a multilayered laminate forming a mask, the laminate on the left a three-layered configuration, and the one or the right a four- layer configuration comprising a high loft material (“open construction NW”).
DETAILED DESCRIPTION
[0016] Preferred masks will comprise at least two spunbond fabric layers with at least one meltblown polypropylene fabric layer sandwiched there between. Additionally, a high loft non wo ven fabric such as an air laid polypropylene high loft fabric (1 or 2 mm to 6 or 10 mm thickness) may also be sandwiched between the spunbond fabric layers and on the face side of the melt blown layer. The meltblown layer can be made from, for example, polypropylene homopolymer and positioned so that there is a perimeter of spunbond primarily consisting of propylene-based elastomer around it. The spunbond top and bottom layers can be made from, for example, polypropylene blended with one or more propylene-based elastomers. These layers can be heat sealed together and/or ultrasonic bonded. After forming the layered structure, the whole structure may be then heat bonded such as at 125°C, or some temperature less than the melting point temperature of the meltblown polypropylene but greater than the melting point temperature of the spunbond propylene-based elastomer layer or zone.
[0017] These masks can be conveniently mass produced and bonded together; three rolls, two spunbond and one meltblown, could be unwound, the melt blown die cut and layered between the spunbond, heat sealed or ultrasonically bonded, and rotary die cut to the final shape, all at high speed and without manual cutting and sewing. If the applied heat damages the electric charge of the fabric, it can be recharged before it is die cut.
[0018] These masks would be comfortable to the user because they will conform to many face shapes and sizes. The masks disclosed herein could support screen printing on the surface to make it fun or stylish such as to print sports team logos and popular cartoon or comic characters. Such masks could be sterilized if needed for multiple use but would preferably be for single use. Given that such masks can be mass produced at low cost given their simple design, this would lend itself to one use and subsequent disposal.
[0019] Masks and packages for the masks are also disclosed. They comprise (or consist of, or consist essentially of) of polyolefins such as polyethylene, polypropylene and propylene- based elastomer, preferably greater than 80, or 90, or 95 wt%, by weight of the materials, of polyolefins. Preferably, the packaging for such masks have two compartments “A” (or first) and “B” (or second). The “A” compartment is for new, unused masks, and the “B” compartment is for masks that have been worn and need to be recycled. After all the masks from the original package have been used, the package, with “A” empty and “B” full, is placed into a recycling bin, or the package is printed with an address and pre-paid postage to act as a recycle mailing pouch. The “A” and “B” compartments can be in one assembly with a partition, or made as two separate but connected compartments, and can optionally have a means to separate the two compartments such as by perforations between the two, or a means of folding one compartment into the other. The masks and packaging can be recycled together.
[0020] As used herein, a “polyolefin” is a polymer comprising a-olefin monomer units, preferably selected from ethylene, propylene, butene, hexene, and octene, most preferably selected from ethylene and propylene. Most preferably, the polyolefins will have a weight average molecular weight within a range from 40,000, or 50,000, or 80,000 g/mole to 100,000, or 400,000, or 500,000, or 600,000 g/mole as determined by gel permeation chromatography (GPC) for such polyolefins, such as disclosed at paragraphs [0051] to [0057] in WO 2018/226345. Polypropylene and propylene-based elastomers, defined further below, are preferred polyolefins.
[0021] As used herein, a “polypropylene” is a polyolefin comprising at least 80, or 90, or 95, or 98 wt%, by weight of the polypropylene, of propylene derived units, and most preferably is a homopolymer of propylene derived units. The melt flow rate (MFR) of the polypropylene can be within a range from 1, or 5, or 10, or 15, or 20, or 25 g/10 min to 45, or 55, or 100, or 300, or 350, or 400, or 450, or 500, or 1000, or 2000, or 2500 g/10 min, as measured per ASTM 1238, 2.16 kg at 230°C. The polypropylene can form thermoplastic blends including from 1 wt% to 95 wt% by weight of the blend of the polypropylene, and is most preferably blended with a propylene-based elastomer.
[0022] The polypropylene is preferably crystalline, as evidenced by having a melting point temperature (Tm) greater than 110°C, greater than 115°C, and greater than 130°C, or within a range from 110, or 115, or 130°C to 150, or 160, or 170°C. The term “crystalline,” as used herein characterizes those polymers which possess high degrees of inter- and intra-molecular order. The polypropylene can have a heat of fusion at least 60 J/g, at least 70 J/g, or at least 80 J/g, as determined by Differential Scanning Calorimetry (DSC) analysis. The heat of fusion is dependent on the composition of the polypropylene. A polypropylene homopolymer preferably has a higher heat of fusion than copolymer or blend of homopolymer and copolymer.
[0023] As referred to herein, the thermal properties of the polypropylene and propylene- based elastomers were determined using DSC. Such DSC data was obtained using a Perkin- Elmer DSC, where 7.5 mg to 10 mg of a sheet of the polymer to be tested was pressed at approximately 200°C to 230°C, then removed with a punch die and annealed at room temperature for 48 hours. The samples were then sealed in aluminum sample pans. The DSC data was recorded by first cooling the sample to -50°C and then gradually heating it to 200°C at a rate of 10°C/minute. The sample was kept at 200°C for 5 minutes before a second coolingheating cycle was applied. Both the first and second cycle thermal events were recorded. Areas under the melting curves were measured and used to determine the heat of fusion and the degree of crystallinity. The percent crystallinity (X%) was calculated using the formula, X% = [area under the curve (Joules/gram)/B(Joules/gram)]»100, where ‘B’ is the heat of fusion for the homopolymer of the major monomer component. These values for ‘B’ were found from the POLYMER HANDBOOK, (4th ed., John Wiley and Sons, New York, 1999). A value of 189 J/g (B) was used as the heat of fusion for 100% crystalline polypropylene. The melting point temperatures (Tm) were measured and reported during the second heating cycle (or second melt).
[0024] As used herein, a “propylene-based elastomer” is a polyolefin random copolymer having crystalline regions interrupted by non-crystalline regions and within the range from 5 to 25 wt%, by weight of the propylene-based elastomer, of ethylene or C4 to C10 a-olefin derived units, and optionally diene-derived units, the remainder of the polymer being propylene-derived units. Most preferably, the propylene-based elastomers herein comprise from 5 to 25 wt%, by weight of the elastomer, of ethylene derived units, the remainder being propylene-derived units. Preferably, the propylene-based elastomer has an MFR within a range from 0.1, or 0.5, or 1 g/10 min to 5, or 10, or 20 g/10 min (ASTM 1238, 2.16 kg at 230°C).
[0025] The term “elastomer” refers to a polymer exhibiting some degree of elasticity, where elasticity is the ability of a material that has been deformed by a force (such as by stretching) to return at least partially to its original dimensions once the force has been removed. Not intended to be limited by any theory, it is believed that the non-crystalline regions may result from regions of non-crystallizable polypropylene segments and/or the inclusion of comonomer units. The crystallinity and the melting point of the propylene-based elastomer are reduced compared to highly isotactic polypropylene by the introduction of errors (stereo and region defects) in the insertion of propylene and/or by the presence of comonomer.
[0026] In any embodiment the propylene -based elastomer has a heat of fusion as determined by DSC of 75 J/g or less, 70 J/g or less, 50 J/g or less, or 35 J/g or less. The propylene-based elastomer can have a lower limit heat of fusion of 0.5, 1, or 5 J/g. For example, the heat of fusion value may be within a range from 1.0, 1.5, 3.0, 4.0, 6.0, or 7.0 J/g, to 30, 35, 40, 50, 60, 70, or 75 J/g. In a preferred embodiment the heat of fusion of the polypropylene is higher than the heat of fusion of the propylene-based elastomer, preferably by at least 5 or 10 J/g-
[0027] In any embodiment, the propylene-based elastomer has a melting point temperature (Tm) of 100°C or 90°C or less, or within a range from 30, or 40°C to 80, or 90, or 100°C.
[0028] The propylene-based elastomer can have a percent crystallinity, as determined according to the DSC of 2% to 65%, 0.5% to 40%, 1% to 30%, or 5% to 35%, of isotactic polypropylene. In any embodiment, the propylene-based elastomer has a crystallinity in the range of 0.25% to 25%, or 0.5% to 22% of isotactic polypropylene. In a preferred embodiment the polypropylene has a higher crystallinity than the propylene-based elastomer.
[0029] In any embodiment the propylene-based elastomers contain at least 60 wt% propylene-derived units by weight of the propylene-based elastomer. In any embodiment, the propylene-based elastomer can be a propylene-based elastomer having limited crystallinity due to adjacent isotactic propylene units and a melting point as described herein. In other embodiments, the propylene -based elastomer can be generally devoid of any substantial intermolecular heterogeneity in tacticity and comonomer composition, and also generally devoid of any substantial heterogeneity in intramolecular composition distribution. The propylene-based elastomer can contain greater than 50 wt%, greater than 60 wt%, greater than 65 wt%, or greater than 75 wt% and up to 99 wt% propylene-derived units, based on the total weight of the propylene-based elastomer. In any embodiment, the propylene-based elastomer includes propylene-derived units in an amount based on the weight of propylene-based elastomer of from 75 wt% to 95 wt%, 75 wt% to 92.5 wt%, 82.5 wt% to 92.5 wt%, or 82.5 wt% to 90 wt%. Correspondingly, the units, or comonomers, derived from at least one of ethylene or a C4 to C10 a-olefin can be present in an amount of 5, or 10, or 14 wt% to 22, or 25 wt% by weight of the elastomer. Commercial examples of such propylene-based elastomers include Vistamaxx™ propylene-based elastomers from ExxonMobil Chemical Company, Tafmer™ elastomers from Mitsui Chemicals, and Versify™ elastomers from Dow Chemical Company. [0030] As used herein, “meltblown” fibers and fabrics refer to fibers formed by extruding a molten thermoplastic material at a certain processing temperature through a plurality of fine, usually circular, die capillaries as molten threads or filaments into high velocity, usually hot, gas streams which attenuate the filaments of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web or nonwoven fabric of randomly dispersed meltblown fibers. Such a process is generally described in, for example, US 3,849,241 and US 6,268,203. Meltblown fibers are microfibers that are either continuous or discontinuous, and, depending on the resin, may have a diameter smaller than 10 microns (for example, for high MFR isotactic polypropylene resins such as Achieve™ 6936G2, available from ExxonMobil Chemical Company); whereas for certain resins (for example, Vistamaxx™ propylene-based elastomer, available from ExxonMobil Chemical Company) or certain high throughput processes such as those described herein, meltblown fibers may have diameters greater than 10 microns, such as within a range from 10 to 30 microns, or 10 to 15 microns. The term meltblowing as used herein is meant to encompass the meltspray process.
[0031] Commercial meltblown processes that utilize extrusion systems can have a relatively high throughput, in excess of 0.3 grams per hole per minute (“ghm”), or in excess of 0.4 ghm, or in excess of 0.5 ghm, or in excess of 0.6 ghm, or in excess of 0.7 ghm. The nonwoven compositions can be produced using commercial meltblown processes, such as a high pressure meltblown process available from Biax-Fiberfilm Corporation, or in test or pilot scale processes. In one or more embodiments, the fibers used to form the nonwoven compositions can be formed using an extrusion system having a throughput rate within a range from 0.01 to 3.0 ghm, or from 0.1 to 2.0 ghm, or from 0.3 to 1.0 ghm.
[0032] In a preferred embodiment the meltblown fabrics used herein have a basis weight (grams per square meter) within a range from 20, or 25 gsm to 45, or 50, or 60, or 80 gsm.
[0033] As used herein, “spunbond” fibers and fabrics refers to fibers and fabrics formed from polymer that is formed by first forming a melt to homogenize the polymers. The extruder supplies melted polymer to a spinneret where the polymer is fiberized as passed through fine openings arranged in one or more rows in the spinneret, forming a curtain of filaments. The filaments are usually quenched with air at a low temperature, drawn, usually pneumatically, and deposited on a moving mat, belt or “forming wire” to form the nonwoven composition. See, for example, in US 4,340,563; US 3,692,618; US 3,802,817; US 3,338,992; US 3,341,394; US 3,502,763; and US 3,542,615. The term “spunbond” as used herein is meant to include fabrics from spunlace processes, in which the filaments are entangled to form a web using highspeed jets of water (known as “hydroentanglement”). The fibers produced in the spunbond process are usually in the range of from 10 to 50 microns in diameter, depending on process conditions and the desired end use for the fabrics to be produced from such fibers. For example, increasing the polymer molecular weight or decreasing the processing temperature results in larger diameter fibers. Changes in the quench air temperature and pneumatic draw pressure also have an effect on fiber diameter.
[0034] In a preferred embodiment the spunbond fabrics used herein have a basis weight (grams per square meter) within a range from 50, or 60 gsm to 85, or 90, or 100, or 140 gsm.
[0035] In any embodiment, the masks comprising the polyolefins described herein can be described as extensible. “Extensible,” as used herein, means any fiber or nonwoven composition that yields or deforms (i.e., stretches) upon application of a force. While many extensible materials are also elastic, the term extensible also encompasses those materials that remain extended or deformed upon removal of the force. For instance, when an extensible facing layer is used in combination with an elastic core layer, desirable aesthetic properties may result because the extensible layer permanently deforms when the elastic layer to which it is attached stretches and retracts. This results in a wrinkled or textured outer surface with a soft feel that is particularly suited for articles in which the facing layer is in contact with a wearer's skin.
[0036] Finally, as used herein, a “polyalphaolefin” (PAO) are compositions that comprise oligomers of a-olefins and are often used as the base stock for synthetic lubricants. PAO can be produced by the polymerization of a-olefins, such as linear a-olefins. A PAO can be characterized as being unbranched, linear, atactic, or by any type of tacticity including isotactic or syndiotactic and/or atactic, and by any degree of tacticity, including isotactic -rich or syndiotactic -rich or fully atactic. PAO liquids are described in, for example, US 3,149,178; US 4,827,064; US 4,827,073; US 5,171,908; and US 5,783,531; and in SYNTHETIC UUBRICANTS AND HIGH-PERFORMANCE FUNCTIONAL FLUIDS, 1-52 (Marcel Dekker, Ueslie R. Rudnick & Ronald U. Shubkin, eds. 1999). PAOs are Group 4 compounds, as defined by the American Petroleum Institute (API). The PAO can comprise C20 to C1500 paraffins, C40 to C1000 paraffins, C50 to C750 paraffins, or C50 to C500 paraffins. The PAO can be dimers, trimers, tetramers, pentamers, etc. of C5 to C14 a-olefins, and Ce to C12 a-olefins, or Cs to C12 a-olefins. Suitable olefins include 1 -pentene, 1 -hexene, 1 -heptene, 1 -octene, 1 -nonene, 1 -decene, 1 -undecene and 1-dodecene. Exemplary PAO are described more particularly in, for example, US 5,171,908, and US 5,783,531; and also in SYNTHETIC LUBRICANTS AND HIGH-PERFORMANCE FUNCTIONAL FLUIDS.
[0037] PAO’ s can have a kinematic viscosity (KV) at 100 °C, as measured by ASTM D445 at 100 °C, of 3 cSt (1 cSt equals 1 mm2/s) to 3,000 cSt, 4 to 1,000 cSt, 6 to 300 cSt, 8 to 125 cSt, 8 to 100 cSt, or 10 to 60 cSt. In some embodiments, the PAO can have a KV at 100 °C of 5 to 1000 cSt, 6 to 300 cSt, 7 to 100 cSt, or 8 to 50 cSt.
[0038] PAO’s can also have a viscosity index (VI), as determined by ASTM D2270, of 50 to 400, or 60 to 350, or 70 to 250, or 80 to 200, or 90 to 175, or 100 to 150. PAO can have a VI, as determined by ASTM D2270, of greater than 100, 110, 120, 150, or 200.
[0039] The PAO is available from ExxonMobil Chemical Company, Houston, Texas under the trade name SpectraSyn. Other useful PAO include those sold under the tradenames Synfluid™ available from ChevronPhillips Chemical Co. in Texas, Durasyn™ available from BP Amoco Chemicals in London England, Nexbase™ available from Fortum Oil and Gas in Finland, Synton™ available from Crompton Corporation in Middlebury Conn., USA, Emery™ available from Cognis Corporation in Ohio.
[0040] Masks such as described herein are made on a machine line that assembles the non wo vens fabrics into laminates from bobbins, ultrasonically or heat welds the layers together, and stamps and cuts the laminates into desirable shapes, and in some embodiments stamps the masks with nose strips, ear loops, and other pieces. Such laminates can be in the form of a sheet of material, or rolled into a roll (like a roll of paper towels as are sold commercially), or other convenient form. In any embodiment, the masks are formed from layered nonwoven fabrics thermally bonded by compressing it through a set of two heated rolls (calendars) for improving fabric integrity and improving fabric mechanical properties. Fundamentals of the fabric thermal bonding process can be found in the review paper by Michielsen et al. “Review of Thermally Point-bonded Nonwovens: Materials, Processes, and Properties”, 99(5) J. APPLIED POLY. SCI. 2489-2496 (2005); or the paper by Bhat et al. “Thermal Bonding of Polypropylene Nonwovens: Effect of Bonding Variables on the Structure and Properties of the Fabrics”, 92 J. APPLIED POLY. SCL, 3593-3600 (2004). The at least two rolls are often referred to as “embossing rolls” and “S-rolls”. In any embodiment, after establishing stable spinning conditions, the calendar temperature is varied to create the bonding curve (i.e., tensile strength versus calendar temperature). Bonding temperatures can vary for the embossing roll from 140 to 155 °C and temperatures for the S-roll can vary from 135 to 155 °C. [0041] The nonwoven fabrics described herein may be a single layer or may be multilayer laminates. One application is to make a laminate from meltblown (“M”) and spunbond (“S”) nonwoven fabrics, which combines the advantages of strength from the spunbonded component and greater barrier properties of the meltblown component. A typical laminate or laminate has three or more layers, a meltblown layer(s) sandwiched between two or more spunbonded layers, or “SMS” nonwoven laminates. Examples of other combinations are SSMMSS, SMMS, and SMMSS laminates. Laminates can also be made of the meltblown or spunbond nonwovens of the invention with other materials, either synthetic or natural, to produce useful articles. Thus, a “nonwoven polyolefin fabric” or a “layer” of such nonwoven polyolefin fabric refers to a fabric formed from fibers of polyolefins (esp. polypropylene and/or propylene-based elastomers) spunbond or meltblown into a fabric, typically having some thickness from 0.1 to 2, or 3 mm in thickness and dimensions on the order of a meter in width and handled as a roll of the material that are unrolled in machinery designed to form articles from such fabric, and layered with one or more other fabrics to form layered laminates and shaped and cut into the article, such as the masks described herein.
[0042] The multilayered laminates are made with any number of rolls of spunbond and meltblown materials in their desirable configuration. Such rolls feed into the manufacturing equipment that allows for layering of the fabrics and bonding the layers as desired. A typical spunbond fabric as a basis weight within a range from 10, or 15 gsm to 25, or 40, or 60, or 80, or 90 gsm which can be tailed by extruding the melted polyolefin onto a conveyor at a desired rate to form a web in which strands bond with each other as they cool. A typical meltblown fabric as a basis weight within a range from 10, or 15 gsm to 25, or 40, or 60, or 80, or 90 gsm which can be tailed by extruding through a die with hundreds of small nozzles and controlling the hot air pressure and allowing the fibers to cool and binding to form a web on a conveyor at a desired rate.
[0043] In any embodiment the masks are made up of a multilayered laminate by covering a layer of meltblown fabric with non wo ven bonded fabric on both sides. Nonwovens are inexpensive to make and clean due to their method of manufacture, and the materials used offers disposability. These disposable masks can be made with more than one filter layers, preferably the meltblown layer, effective at filtering out particles above 1 micron. The filtration level of a mask depends on the fiber, the way it is manufactured, the web’s structure, and the fiber’s cross-sectional shape. Completed masks are preferably sterilized before being sent out of the factory and worn. [0044] Thus, in any embodiment is a mask comprising one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask. The mask takes on the structure of the base multilayered laminate used to make it, which comprises SMS in one embodiment, or SSMSS, or SSMMSS, or SMMS, or SSMMS, or SMSS, SSMSMSMS etc. The “inner face layer” or “inner layer” is the one or more layers, preferably spunbond fabric, that is designed as part of the mask to contact the wearer’ s face and preferably of a size that would fit over at least the nose and chin (in width, MD direction) and at least across the cheeks of the wearer (in length, CD direction). The “outer visible layer” or “outer layer” is the layer that faces away from the wearer, and is visible by others viewing the wearer.
[0045] The outer and inner layers do not need to be the same length in the CD direction. One or the other layer, preferably the inner layer, can define the overall shape of the mask and the bands on either side for fastening the mask to the wearer’s head, while the outer layer can be of any length so long as it is long enough to cover the middle layer and be attached to the inner layer such as to form a pocket or envelope for the middle layer. Figures 1 to 4 demonstrate an embodiment wherein the outer layer is not coextensive with the inner layer. The outer an inner layers can also be the same or similar such that they are coextensive in the CD direction. In any case, most preferably, the inner and outer layers are the same or similar width in the MD direction.
[0046] Preferably, the masks disclosed herein are extensible. This is because the multilayered laminate from which they are made are extensible, wherein at least the inner and outer layers are preferably extensible either by the structure of the fabric itself, the polyolefins from which they are made, or both.
[0047] In any embodiment, the inner and outer layers can be nonwoven materials made by any means, but preferably there is at least one inner face layer and at least one outer visible layer that are spunbond polypropylene. Preferably, the at least one middle layer is a meltblown polypropylene. Thus, the at least one inner layer and at least one outer layer sandwiches the at least one middle layer there between, and that layer is free to move as it is not attached to any inner or outer layer. It is preferably sandwiched such that it presses against the inner and outer layers when the mask is stretched out across the wearer’ s face, but is otherwise not attached to any layer and free to move of float in the pocket created by the inner and outer layers. Preferably, at least the one meltblown layer is electrostatically charged, but any number of layers may also be electrostatically charged.
[0048] Across the CD direction of the mask there is a band section, then a central or breathable portion followed by another band section. In any embodiment there are perforations, slits and/or holes located at least along a central portion of the inner and outer layers to facilitate air flow between the ambient air and the wearer’s nose and/or mouth, hence, the term “breathable portion”.
[0049] In any embodiment the polyolefin comprises (or consists essentially of) polypropylene and/or propylene-based elastomers comprising at least 60, or 70, or 80 wt%, by weight of the polypropylene or propylene -based elastomers, of propylene-derived units. In any embodiment, any layer of the mask can comprise (or consist essentially of) polypropylene, a propylene-based elastomer, or a blend of the two. Preferably one or more of the inner face layer and outer visible layers comprises a propylene-based elastomer. In any embodiment the mask further comprises a high loft nonwoven layer between the outer and inner layers, preferably on the face side of the middle layer. An example of a high loft fabric is Enkamat™ or Polartec™ high loft material (polyester or polyolefin 3-D matting composed of randomly laid monofilaments, also called “batting” or “wadding”), most preferably the polypropylene grade of high loft nonwoven, preferably composed of polypropylene staple fibers bonded with bicomponent fibers. Such high loft layer may be bonded to the inner or outer layer, most preferably the inner layer prior to mask assembly; and may be bonded by a variety of methods including a polypropylene-based hot melt or ultrasonically. An example of such a construction is shown in Figure 7. Thus, the masks including the high loft layer may take a structure such as SLMS, SSLMS, SSLMSS, SLMMS, etc., wherein “L” is the high loft layer of material.
[0050] Thus constructed, the mask if designed to fit snuggly against the face of the user and have a soft feel. The mask can be made in various sizes to fit firmly against the skin of the wearer and expand and contract with the wearer’s facial movements. In any embodiment the at least one of the inner face layer and/or outer visible layers forms a band, wherein each end can be fastened together by the wearer. Preferably, the at least one of the inner face layer and/or outer visible layers forms a band, wherein each band comprises one or more ear slits for fastening to the head of the wearer. To further enhance the soft feel, in any embodiment the outer and/or inner layers further comprise a polyalphaolefin; wherein the polyalphaolefin is present within a range from 1, or 2, or 5 wt% to 10, or 15 or 20 wt%, by weight of the polyolefin and polyalphaolefin. [0051] To enhance the fit of the mask against a wearer’s face, the mask may further comprise polyolefin plugs, preferably soft foam plugs, attached to the inner face layer to contact the nose and cheeks of the wearer. Most preferably the plugs comprise polypropylene.
[0052] The bands can take any desirable form to facilitate attachment of the mask across the wearer’s face. The bands can form a tie to be fastened around the head, or may have slits or cut-outs for each ear. In any embodiment the mask comprises at least two layers of non wo ven polyolefin fabric, an inner face layer and an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer.
[0053] Desirably, the masks are made only from polyolefins, most preferably from polypropylene and/or propylene-based elastomers, and thus adhesives and non-polyolefin materials are absent; preferably wherein the mask consists of polypropylene and/or propylene- based elastomers.
[0054] The masks made as described can be easily constructed by common multilayer laminate construction means, such as by feeding each layer from a roll of material down a line and laying each layer upon the other and attaching the layers as necessary to for the bands and breathable portion with the floating middle layer and optional high loft layer. In any embodiment all of the layers of the mask are aligned such that the layers of nonwoven polyolefin (roll goods) may be fed and die cut in a manufacturing configuration allowing for at least 5,000, or 10,000 masks/hour to be produced.
[0055] Once produced, the masks can be packaged (for transport and sale) in a tandem pouch having at least a first compartment and a second compartment, wherein one or more new, unused masks are in the first compartment and one or more used masks are placed in the second compartment. In this manner, the tandem pouch can then be dropped off at a recycle facility for complete recycling. Thus in any embodiment is a method of forming a mask comprising feeding at least three layers of nonwoven polyolefin, an inner face layer and an outer visible layer, to envelope at least one middle layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer resides unattached.
[0056] The masks described herein can be elucidated with reference to an embodiment shown in Figures 1 to 4, showing a perspective from above the layers of nonwoven fabric used to make the mask, and being formed in the machine direction from the rolls of fabric moving downward on the Figures. With reference to Figure 1, an inner face layer 10 having a number perforations or holes 16 is provided, a section highlighted in shaded gray, with an outer visible layer 12 also having perforations or holes 16, sandwiching there between a middle nonwoven fabric layer (“middle layer”). Preferably, the inner and outer layers 10 and 12 are comprised of spunbond polyolefins, most preferably spunbond polypropylene, while the middle layer comprises a meltblown propylene-based elastomer. Additionally, one or more layers of a high loft material, preferably high loft polypropylene, may also be sandwiched between the inner and outer layers 10 and 12. Such high loft may be fastened to the inner and/or outer layers, or float freely within an envelope or pocket made by the inner and outer layers 10 and 12.
[0057] With reference to Figure 2 is shown the formed multilayered laminate 18 comprising at least the inner and outer layers 10 and 12, and middle layer 14, the multilayered laminate 18 having a band section 20 on each side of a breathable portion 24 located where the middle layer 14 is enveloped by the inner and outer layers 10 and 12, wherein heat bonds 22 are used to adhere the inner layer 10 to the outer layer 12 and allow the at least one middle layer 14 of meltblown fabric and optional high loft fabric to float freely within the envelope, not attached to any layer of fabric. The so-called “attachment” of one fabric to another is typically accomplished using heat bonding such that the fabric layers are melted between one or more heated pressure points or lines (e.g., a platen or other heated element) and thus form a heat bonds to one another while in a molten or partially molten state. Most preferably, additional adhesives are absent from such a multilayered laminate f8.
[0058] With reference to Figure 3, the multilayered laminate f8 continues to move down the line in the MD where it comes to a station/section for forming die cuts 26. These die cuts 26 can be of any number, shape, and complexity and are useful in forming individual sections, components, and ultimately, the masks themselves. In Figure 3, it can be seen that some die cuts 26 run across the entire CD of the multilayered laminate 18 and the breathable portion 24, while some other die cuts 26 only cut across a section of the band section 20.
[0059] With reference to Figure 4 is a top view of a representative mask 28 having a band or tie portion 30 on each side of the breathable portion 32. The wearer of the mask will then fit the mask across his/her face such that the breathable portion 32 fits over the nose and mouth and then wrap the tie portions 30 around the head and/or ears.
[0060] Another embodiment of the masks described herein is represented in the top view drawing in Figure 5, wherein mask 34 comprises perforations or holes 36 in a breathable section and the cut away section 38 forms a ring that is useful to attach the mask 34 to the ears of the wearer. The embodiment of the mask in Figure 6 shows a mask 40 comprising perforations or holes 42 in a breathable section while cut away sections 44 and 46 form alternative rings to attach the mask 40 to the ear of the wearer, the different sections 44 and 46 allowing for different size fits. The cutaway sections 44 and 46 depicted in Figure 6 can also be slots cut into the fabric of the mask 40 on each side of the central section along the bands.
[0061] A edge cut-away view through the top of a mask as it sits against a wearer’ s face is shown in Figure 7, wherein on the left is a three-layer mask demonstrating how air would flow between the ambient air (air external of the outer layer) and the wearer’s mouth and/or nose. The drawing on the right demonstrates the effected of added air flow using a high loft fabric or batting, in this case between the inner layer and the middle layer. The dotted lines represent the inner and outer layers, preferably spunbond fabrics. The added high loft layer makes the effective breathable area of the mask larger by distributing air flow.
[0062] An exemplary mask could comprise at least two spunbond fabrics with at least one meltblown polypropylene layer sandwiched there between. The meltblown layer can be made from, for example, polypropylene homopolymer such as Achieve™ Advanced PP6936G2, and positioned so that there is a perimeter of spunbond primarily consisting of propylene -based elastomer around it. The meltblown middle layer is preferably 25 to 35 gsm. The spunbond inner and outer layers can be made from, for example, ExxonMobil™ PP3155E5 polypropylene blended with Vistamaxx™ 7050BF propylene-based elastomer. The spunbond layers are preferably 75 to 85 gsm. The blend may comprise at least 40, or 50, or 60, or 70, or 80 wt%, by weight of the blend, of propylene-based elastomer. These layers can be heat sealed together and/or ultrasonic bonded. After forming the layered structure, the whole structure may be then heat bonded such as at 125°C, or some temperature less than the melting point temperature of the meltblown polypropylene but greater than the melting point temperature of the spunbond propylene-based elastomer layer or zone.
[0063] Mechanical handling of elastic soft masks can be difficult due to their light weight and lack of stiffness. In any embodiment, a series of steps can be taken to alleviate this problem. Two methods are possible. Carefully layering, bonding and die cutting allows ‘tear- off’ masks on a roll of the multilayered laminate of masks. But alternatively, in any embodiment, instead of perforations, die cut individual masks can be layered on one or both sides of the multilayered laminate in a biaxially oriented polypropylene film.
[0064] In any embodiment, the nonwoven layer roles can be unwound into an inner spunbond layer, middle meltblown layer, and outer spunbond layer of the laminate. Die cuts are made for the ear slits, and the spunbond layers are attached by applying ultrasonic bonding. Then in any embodiment a roll of film, a biaxially oriented polypropylene film most preferably, is unrolled onto the outer and inner sides of the laminate of masks. Next, a die cut of the rounded outer perimeter is made, and the center perimeters are perforated. The perforations are staggered to not allow any filaments to ‘bridge’. Finally, excess material is removed and the parts are wound onto a roll.
[0065] Alternatively, in any embodiment a die cut can be made through all three nonwoven layers of the laminate, then a biaxially oriented polypropylene roll can be unwound onto either the inner or outer spunbond layers (or both) of the laminate forming the mask. Next a die cut of the rounded perimeter and the central sections where the nonwovens are cut through is made; at this point the laminate sheet is cut completely into separate masks but the biaxially oriented polypropylene film is continuous at three segments. Finally, the biaxially oriented polypropylene sections are perforated. The masks can then be separated by tearing the perforated biaxially oriented polypropylene sections. The outer film layer will make handling the masks simpler. The films can be attached by heat or be use of an adhesive.
[0066] Thus in any embodiment the masks herein further comprise at least one layer of polypropylene film, preferably on the outside of either side of the mask, that is, on the “outside” portions that are touched by the users, the sides facing away from the at least one middle layer of the mask. The film is preferably added to the laminate while it is being formed on the equipment that unrolls, layers and cuts the laminate into individual masks. Thus, the structure in any embodiment is one of FSMS, FSMSF, FSSMSSF, etc., wherein “F” is a film. Including the high loft material, the structure of the laminate forming the mask, or the mask itself, may take the form of FSLMS, FSLMSF, FSSLMSSF, FSLMMSF, FSLMMS, etc. In a most preferred embodiment, the side of the laminate that forms the inner layer, the layer that will make contact with human skin, will not have a film layer. Having the one layer of film can still facilitate the handling of the masks, or the attachment of the masks into the form of a roll that can then be easily tom away for individual use from the roll, much like an individual paper towel from a roll of paper towels.
[0067] As used herein, a “film” is a thin flexible material that is continuous (not porous) and is within a range from 20, or 50 pm to 250, or 300, or 400 pm in average thickness, preferably made by blowing or casting molten polyolefin, preferably polypropylene, into the thin film. It is most preferably biaxially oriented, meaning that while being formed it has been stretched in the MD and CD such that the polymer molecules have been allowed a degree of orientation. Preferably, the film is extensible, and most preferably is extensible and elastic.
[0068] In any embodiment the invention described herein includes a laminate roll comprising (or consisting of, or consisting essentially of) multiple masks comprising one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer sandwiched between the inner face layer and outer visible layer, the at least three fabric layers of an inner face layer, a middle layer, and an outer visible layer forming a laminate; at least one layer of a film on at least the outer visible layer of the laminate roll to form a tearable laminate, wherein the laminate is cut (scored or perforated) into individual masks to allow individual masks to be tom away from one another from the sheet or roll of laminate; and wherein the tearable laminate is in the form of a roll. As would be understood by those skilled in the art, a “cut” may comprise a score or series of perforations (such as made by a die cutter or blade) in the material that can allow the components or parts on either side of the score to be torn from one another, but a die cut can also result in a score or perforations that results in the material components or parts to sever from one another without any further force. [0069] In any embodiment the inner face layer and outer visible layers in the laminate roll are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask.
[0070] Also in any embodiment of the laminate roll at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer.
[0071] As used herein, the phrase “consisting essentially of’ for the masks and the polyolefins that make up the masks means that there may be up to 1, or 2, or 3, or 4 wt%, by weight of the polyolefins, of additives such as antioxidants, cross-linking agents, peroxides and other visbreaking agents, alkyl radical scavengers, acid neutralizers, nucleating agents, fillers, colorants, polymeric compatibilizers (other elastomers, plastomers, LDPE, etc.), hydrocarbon resins, and/or other such additives as are known in the art. Likewise, as it relates to a process claim, “consisting essentially of’ does not exclude minor procedures such as rolling, heating, bending, layering, perforating that are not essential to the mask structure and function and/or are otherwise non-reactive with the claimed components.
[0072] All publications, patents and patent publications mentioned herein are incorporated by reference to the same extent as if each individual publication, patent, or patent publication was specifically and individually indicated to be incorporated by reference.
[0073] The mask and methods of making the mask thus described, it will be apparent that its descriptive elements and ranges may be varied in many ways and that such variations are not to be regarded as a departure from the scope of the invention; and that all such modifications apparent to one skilled in the art in light of this Specification are intended to be included within the scope of the following claims.

Claims

1. A mask comprising: one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask.
2. The mask of claim 1, wherein one or more inner face layers and one or more outer visible layers are spunbond polyolefin.
3. The mask of any one of the previous claims, wherein the at least one middle layer is a meltblown polyolefin.
4. The mask of any one of the previous claims, wherein there are perforations, slits and/or holes located at least along a central portion of the inner and outer layers to facilitate air flow between the ambient air and the wearer’ s nose and/or mouth.
5. The mask of any one of the previous claims, wherein the one or more inner face layers and one or more outer visible layers comprises a propylene-based elastomer; and wherein the at least one middle layers comprises polypropylene; and wherein the polypropylene has a higher crystallinity (and/or higher heat of fusion) than the propylene-based elastomer.
6. The mask of any one of the previous claims, further comprising a high loft nonwoven layer between the outer and inner layers, preferably on the face side of the middle layer.
7. The mask of any one of the previous claims, wherein all of the layers are aligned such that the layers of nonwoven polyolefin may be fed and die cut in a manufacturing configuration allowing for at least 5,000, or 10,000 masks/hour to be produced. The mask of any one of the previous claims, further comprising polyolefin plugs, preferably soft foam plugs, attached to the inner face layer to contact the nose and cheeks of the wearer. The mask of any one of the previous claims, wherein the polyolefin comprises polypropylene and/or propylene-based elastomers comprising at least 60 wt%, by weight of the polypropylene or propylene-based elastomers, of propylene-derived units. The mask of any one of the previous claims, wherein at least one of the inner face layer and/or outer visible layers forms a band, wherein each end can be fastened together by the wearer. The mask of any one of the previous claims, wherein at least one of the inner face layer and/or outer visible layers forms a band, wherein each band comprises one or more ear slits for fastening to the head of the wearer. The mask of any one of the previous claims, wherein the outer and/or inner layers further comprise a polyalphaolefin; wherein the polyalphaolefin is present within a range from 1, or 2, or 5 wt% to 10, or 15 or 20 wt%, by weight of the polyolefin and polyalphaolefin. The mask of any one of the previous claims, wherein the mask is of a size to fit firmly against the skin of the wearer and expand and contract with the wearer’s facial movements. The mask of any one of the previous claims, further comprising at least one layer of polypropylene film, preferably on the outside of either side of the mask. The mask of any one of the previous claims, wherein adhesives and non-poly olefin materials are absent; preferably wherein the mask consists of polypropylene and/or propylene-based elastomers. The mask of any one of the previous claims, wherein one or more masks are packaged (for transport and sale) in a tandem pouch having at least a first compartment and a second compartment, wherein one or more new masks are in the first compartment and one or more used masks are placed in the second compartment. A mask comprising: one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer between the inner face layer and outer visible layer, wherein at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer. The mask of claim 17, wherein one or more inner face layers and one or more outer visible layers are spunbond polyolefin. The mask of any one of the previous claims 17 and 18, wherein the at least one middle layer is a meltblown polypropylene. The mask of any one of the previous claims 17 to 19, wherein there are perforations, slits and/or holes located at least along a central portion of the inner and outer layers to facilitate air flow between the ambient air and the wearer’s nose and/or mouth. The mask of any one of the previous claims 17 to 20, wherein the one or more inner face layers and the one or more outer visible layers comprises a propylene -based elastomer. The mask of any one of the previous claims 17 to 21, further comprising a high loft non wo ven layer between the outer and inner layers. The mask of any one of the previous claims 17 to 22, wherein all of the layers are aligned such that the layers of nonwoven polyolefin may be fed and die cut in a manufacturing configuration allowing for at least 5,000, or 10,000 masks/hour to be produced. The mask of any one of the previous claims 17 to 23, further comprising polyolefin plugs attached to the inner face layer to contact the nose and cheeks of the wearer. The mask of any one of the previous claims 17 to 24, wherein the polyolefin comprises polypropylene and/or propylene-based elastomers comprising at least 60 wt%, by weight of the polypropylene or propylene-based elastomers, of propylene-derived units. The mask of any one of the previous claims 17 to 25, wherein at least one of the inner face layer and/or outer visible layers forms a band, wherein each end can be fastened together by the wearer. The mask of any one of the previous claims 17 to 26, wherein the mask is of a size to fit firmly against the skin of the wearer and expand and contract with the wearer’s facial movements. The mask of any one of the previous claims 17 to 27, wherein the meltblown layer is electrostatically charged. The mask of any one of the previous claims 17 to 28, wherein adhesives and nonpolyolefin materials are absent; preferably wherein the mask consists of polypropylene and/or propylene-based elastomers. The mask of any one of the previous claims 17 to 29, wherein one or more masks are packaged (for transport and sale) in a tandem pouch having at least a first compartment and a second compartment, wherein one or more new masks are in the first compartment and one or more used masks are placed in the second compartment. The mask of any one of the previous claims 17 to 30, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask A method of forming a mask comprising: feeding at least three layers of nonwoven polyolefin forming an inner face layer and an outer visible layer to envelope at least one middle layer between the inner face layer and outer visible layer,
-21- wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer resides unattached. The method of claim 32, wherein there is at least one inner face layer and at least one outer visible layer that are spunbond polypropylene. The method of any one of the previous claims 32 to 33, wherein the at least one middle layer is a meltblown polypropylene. The method of any one of the previous claims 32 to 34, wherein there are perforations, slits and/or holes located at least along a central portion of the inner and outer layers to facilitate air flow between the ambient air and the wearer’s nose and/or mouth. The method of any one of the previous claims 32 to 35, wherein one or more of the inner face layer and outer visible layers comprises a propylene -based elastomer. The method of any one of the previous claims 32 to 36, further comprising a high loft non wo ven layer between the outer and inner layers. The method of any one of the previous claims 32 to 37, wherein all of the layers are aligned such that the layers of nonwoven polyolefin are fed and die cut in a configuration allowing for at least 50,000, or 100,000 masks/hour to be produced. A laminate roll comprising multiple masks comprising: one or more layers of nonwoven polyolefin fabric forming an inner face layer and one or more layers of nonwoven polyolefin fabric forming an outer visible layer, and at least one middle nonwoven fabric layer sandwiched between the inner face layer and outer visible layer, the at least three fabric layers of an inner face layer, a middle layer, and an outer visible layer forming a laminate; at least one layer of a film on at least the outer visible layer of the laminate roll forming a tearable laminate, wherein the laminate is cut into individual masks; and wherein the tearable laminate is in the form of a roll.
-22-
40. The laminate roll of claim 39, wherein the inner face layer and outer visible layers are at least partially attached to one another and form a pocket wherein the at least one middle layer is not attached to any layer of the mask. 41. The laminate roll of claim 39, wherein at least one of the inner face layer and/or outer visible layers forms a band, and wherein each band comprises at least one ear slit for fastening to the head of the wearer.
-23-
PCT/US2021/043671 2020-08-11 2021-07-29 Face masks incorporating elastomeric layers and methods of producing such face masks Ceased WO2022035607A1 (en)

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