PERSONAL PROTECTIVE EQUIPMENT

Abstract

An antimicrobial fabric formed of fibers containing nano-sized particles of zinc on a surface of the fibers. Various articles made from the fabric are also disclosed.

Claims

1. An antimicrobial fabric formed of fibers having nanosized particles of zinc exposed in part on a surface of the fibers.

2. The fabric of claim 1, wherein the fibers contain carbon nanotubes dispersed intermittently within the fibers during fiber formation, and wherein the particles of zinc are selected from the group consisting of elemental zinc particles, zinc oxide and zinc salt.

3. The fabric of claim 1, wherein the zinc particles have a size range of 1 to 1,000 nanometers, preferably 1 to 500 nanometers, more preferably 1 to 100 nanometers.

4. The fabric of claim 1, wherein the nanosize particles of zinc are adhered to or held by the surface of the fibers.

5. The fabric of claim 1, wherein the fibers comprise thermosetting thermoplastic fibers, preferably polyethylene fibers or polypropylene fibers.

6. The fabric of claim 1, wherein the fibers are formed by co-extruding polyethylene fibers with a core fiber formed of the same or a different thermoplastic material or with a thermosetting material.

7. Personal protective equipment formed at least in part of fabric as claimed in claim 1, wherein a surface of the fabric is configured to be in close or direct contact with the skin of the wearer, at least in part, when worn, and wherein the particles are arranged so that the fabric in close or direct contact with the skin of the wearer forms a plurality of half-calls of an air-zinc battery.

8. The personal protective equipment of claim 7, in the form of a mask.

9. The personal protective equipment of claim 7, in the form of scrubs, gowns or caps.

10. The personal protective equipment of claim 6, in the form of sheets or pillow covers, towels and wraps.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Further features and advantages of the present invention will be seen from the following detailed description, taken in conjunction with the accompanying drawings, wherein like numerals depict like parts, and wherein:

[0014] FIG. 1 is a flow diagram showing a preferred method of forming nano particle size metal particles coated fibers in accordance with the present invention;

[0015] FIGS. 2-5 are views similar to FIG. 1 of an alternative methods for forming nano particle size metal particles coated fibers in accordance with the present invention;

[0016] FIG. 6 is a side elevational view of monofilaments fiber made accordance with the present invention;

[0017] FIG. 7 is a plan view of a surgical mask formed in accordance with the present invention; and

[0018] FIG. 8 is a plain view showing various articles of personal protective equipment made in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0019] As used herein the term “microbe” or “pathogen”, which are used interchangeably, may include bacteria, algae, fungi, molds, yeasts, and viruses including but not limited to the common cold, influenza, SARS, H1N1, Swine Flu and COVID-19 commonly know as “Coronavirus”.

[0020] “Personal protective equipment” or PPE may include masks, scrubs, respirators, caps and other headgear such as face shields, and other types of clothing as well as sheets, pillowcases, and the like.

[0021] “Metal particles” may include elemental zinc particles and oxides and salts thereof.

[0022] “Fibers” include natural and artificial fibers, preferably thermoplastic and thermosetting fiber materials more preferably, polyethylene.

[0023] And “metal filled fibers” means fibers, having metal particles carried on or within the fibers, and in which at least some of the metal particles are at least in part exposed to air.

[0024] The present invention in one aspect provides a method forming nanosized metal particle filled fibers suitable for weaving or knitting into a fabric for use in forming personal protective equipment. More particularly, the present invention in one aspect provides a method for producing nanosized metal particle containing fibers that are capable of forming metal-air electrochemical cells, capable of releasing ions when adjacent or in contact with a wearer's skin or moisture.

[0025] The metal particle fiber matrix interacts with exhaled moisture and oxygen, or moisture and oxygen from the wearer's skin surface, and/or ambient moisture and oxygen to generate a microcurrent. An electric field is created without an external battery source, which destrous virulent microbes or pathogens including Coronavirus.

[0026] Referring to FIG. 1, according to a first embodiment of our invention, metal particles, typically metallic zinc particles which may be previously formed by grinding or precipitated out of suspension, and having an average particle size between 1 to 1,000 nanometers, more preferably 1 to 500 nanometers, even more preferably 1 to 100 nanometers are mixed with a thermoplastic material such as polyethylene in a heated mixing vat 10 to melt the thermoplastic material, and the mixture bump extruded or melt spun at spinning station 12 to form fibers 14, having nanometer size metal particles 16 (see FIG. 3). Polyethylene is the polymer of choice for releasing of electrons from the metal. The porosity of the fiber also is believed to play a part. Polyacrylic or polyester fibers also may be used; however polyacrylic or polyester fibers result is a slower ion release. The nanometer sized metal particles filled fibers may then be cabled or twisted at a cabling station 18, and woven at a weaving or knitting station 20, or laid in a non-woven manner, into a fabric in which the zinc nano particles are separated in discrete patterns or lines as described in our parent U.S. application Ser. No. 15/823,076, and in our earlier U.S. Pat. Nos. 9,192,761 and 9,707,172, the contents of which are incorporated herein by reference, which is then used to form personal protective equipment such as a mask (FIG. 7) as described below, or made into a hospital scrub or cap, gown or scrub, or a sheet, pillow case, towels, wipes, etc., as shown in FIG. 8.

[0027] Referring to FIG. 2, according to a second embodiment of the invention, nanosized metallic zinc particles having an average particle size between 1 and 1,000 nanometers, preferably 1 to 500 nanometers, even more preferably about 1 to 100 nanometers are mixed with a thermosetting polymer material such as polyester chips in a melting vat 22. The molten mixture is expressed through a spinneret at station 24 to form an elongate thread having metal particles incorporated into the thread with the metal particles exposed at least in part on the surface of the thread. The thread is then cabled or twisted at a cabling station 26, woven into cloth at a weaving station 28, and the cloth with metal-free threads or cables formed into personal protective equipment at step 30.

[0028] Referring to FIG. 3 according to a third embodiment of the invention, nanosized metallic zinc particles having an average particle size between 1 and 1000 nanometers, preferably 1 to 500 nanometers, even more preferably 1 to 100 nanometers, are heated and hot sprayed from a hot sprayer 30 onto preformed fibers or threads 32 whereupon the nano particles adhere to the surface of the fibers or threads. Alternatively, as shown in FIG. 4, a preformed thread 40 are pulled through a vat 42 containing loose mass of nanosized metallic zinc particles of wherein the zinc nano particles key micropores interstices in the fiber surface.

[0029] Referring to FIG. 5, and yet another embodiment, metallic zinc particles are printed via printer head 60 onto a surface 62 of a preformed fabric in discontinuous lines as discussed below.

[0030] FIG. 7 illustrates a mask made in accordance with the present invention. As shown, mask 100 comprises an outer cloth layer 102, a middle cloth layer 104 and an inner cloth layer 106. Outer layer 102 and middle layer 104 are formed of a conventional cloth. Inner layer 106 comprises a fabric having a plurality of spaced metal deposition areas 120. As shown, the plurality of individual metal deposition areas 120 are discontinuous and uniformly distributed on the surface of the fabric 106, in imaginary spaced lines or lines of dots, to cover a substantially consistent percentage of the surface area of the fabric 106. Typically, the lines or lines of dots are evenly spaced at spacings from 0.1 to 3 mm, preferably 0.2 to 2 mm, more preferably 0.3 to 1.5 mm, most preferably 0.5 to 1.0 mm. The concentration of zinc particles in the threads that form the line or deposition determines the amount of zinc available for forming an air-zinc battery as will be described below. Preferred concentration is 30% but the lowest is about 1% and the highest about 50%. In certain embodiments, the metal deposition area patterns 120 cover from about 10% to about 90% of the surface area of the fabric layer 106. In other embodiments, the metal deposition areas 120 cover from about 20% to about 80%, from about 15% to about 75%, from about 25% to about 50%, or from about 30% to about 40% of the surface area of the fabric layer 106. Although FIG. 4 shows the plurality of metal deposition areas 120 substantially uniformly distributed on the surface of the fabric layer 106, in other embodiments, the plurality of metal deposition areas 120 may be randomly distributed on the surface of the fabric layer 106. Typically, the lines have a thickness of 0.1 to 3 mm, preferably 0.2 to 2 mm, more preferably 0.3 to 1.0, most preferably 0.4 to 0.5 mm. The spaced lines may be continuous and may take various forms including straight, curved and various angular shapes depending on the weave. The actual shape of the lines is not important. Preferably, but not necessarily, the lines are approximately equal in thickness and are evenly spaced.

[0031] The mask 100, as illustrated in FIG. 7, comprises a three-layer fabric mask, but alternatively may comprise two, or four or more layers of fabric including the fabric layer containing the metal nano-particles forming the innermost surface or layer of the mask. Alternatively, the metal nano-particles containing a fabric may be formed as filter insert or element on the innermost surface or layer of the mask.

[0032] Completing the mask are fasteners such as ear straps or head straps 120 configured to attach the mask to the head of the wearer.

[0033] The present invention is unique in that the zinc pattern grid on the tactile layer creates a matrix of individual half-cells (anodes) for ion exchange with the skin of the wearer which effectively kills microbes on or adjacent the skin of the wearer or between the skin and the tactile layer. However, the zinc pattern grid does not have to be in direct contact with the skin of the wearer. One-half cell of electrochemical reaction is the zinc impregnated fabric (the anode), and the other is the skin of the wearer, with the breath of the wearer or moisture from the skin of the wearer, supplying moisture and oxygen (the cathode) completing the circuit for microcurrent production. Alternatively, the oxygen and moisture may be supplied, in part, from ambient air.

[0034] There results a Zinc-air battery powered by oxidizing zinc with oxygen from the air. During discharge, zinc particles form a porous anode, which is saturated with an electrolyte, namely moisture from the breath or skin of the wearer or from the air. Oxygen from the air or skin of the wearer reacts at the cathode and forms hydroxyl ions which migrate into the zinc paste and form zinc hydroxide Zn(OH).sub.2, releasing electrons to travel to the cathode. The chemical equations for the zinc-air battery formed using Applicants' zinc-coated masks and ambient oxygen are as follows:

[0035] Anode: Zn+4OH.sup.−.fwdarw.Zn(OH).sub.4.sup.2−+2e.sup.−(E.sub.0=−1.25 V)

[0036] Fluid: Zn(OH).sub.4.sup.2−.fwdarw.ZnO+H.sub.2O+2OH.sup.−

[0037] Cathode: ½O.sub.2+H.sub.2O+2e.sup.−.fwdarw.2OH.sup.−(E.sub.0=0.34 V)

[0038] Overall, the zinc oxygen redox chemistry recited immediately hereinabove comprises an overall standard electrode potential of about 1.59 Volts.

[0039] There is a certain amount of gas exchange at the skin surface with a partial pressure of oxygen. The oxygen at the skin surface is a product of ambient oxygen in addition to oxygen diffusion from capillary blood flow. In certain embodiments, the zinc in contact with a patient's skin or breath resulting from wearing, for example, our zinc-containing mask, in combination with moisture from the skin or breath of the wearer and transcutaneous oxygen complete the galvanic circuit described hereinabove.

[0040] The chemistry utilized by Applicants' zinc-coated mask differs from a more conventional galvanic cell. A galvanic cell, or voltaic cell is an electrochemical cell that derives electrical energy from spontaneous redox reactions taking place within the cell. It generally consists of two different metals connected by a salt bridge, or individual half-cells separated by a porous membrane. In contrast, the chemistry of Applicants' zinc-air battery does not require use of a second metal. Applicants' device acts as a powerful antimicrobial exhibiting a virus reduction or kill in excess of 99%.

[0041] The fabric is configured to contact the skin or breath of the wearer and to generate an electric current and metal ions when the metal ions bind with ambient oxygen or oxygen from the skin of the wearer. The generation of such an electric current kills microbes in the vicinity. Another added advantage is that the zinc-air battery may reduce mask rash, and zinc and oxygen are healthy for the skin.

[0042] The fabric described herein also may be used in the manufacture of various personal protective equipment such as gowns, scrubs, caps, etc., as well as various clothing items as well as sheets, pillow cases, towels, wipes, etc. that may come into contact with or close proximity to the skin. FIG. 8 shows various examples of personal protective equipment made in accordance with the present invention including hospital gowns, caps, as well as sheets and pillow cases, etc.

[0043] Various changes may be made in the above invention without departing from the spirit and scope. For example, the fibers may be co-extruded to have a center or core of the same or dissimilar polymer with the metal filled polymer on the outside of the fiber. Co-extrusion has the advantage that the center of the fiber is void of metal and therefore can contribute more strength to the fiber, while the outer layer may be loaded with metal particles. Or, the metal filled polymer may be intermittently dispersed into discrete reservoirs within the fiber during fiber formation. And, of carbon fiber nanotubes (hollow-tubes) can be added to provide increased tensile strength as well as the antimicrobial nature of the hollow tubes. The carbon nanotubes also are electrically conductive and will electrically connect the zinc particles in the reservoir into a layer mass so that the available zinc ions are interconnected providing a layer capacity or discharge. Additionally, if there is a recharging effect of free floating H+ ions, then the carbon nanotubes also will enable more even recharging of the zinc mass. Also, the amount of metal particles in the fibers may be adjusted to adjust the capacity or voltage of the air battery in the thread or yarn.