Patent Application
20230276880
First responders, medical personnel, and other public service providers are positioned to be on the front lines in treating patients with exposure to microorganisms, such as bacteria and viruses. For example, more virulent and drug resistant strains of pathogenic bacteria are being identified around the globe. The worldwide pandemic related to the Coronavirus, for instance, further accentuates the hazards faced by first responders and medical personnel.
First responders, including emergency medical personnel and firefighters, and other health care providers can be exposed to both bacteria and viruses in a direct manner or in an indirect manner. Protecting the above personnel from viruses, such as the Coronavirus, is particularly problematic. Viruses, for instance, reproduce by infecting a host cell and then multiply in great numbers. Recent studies have indicated that the infection rate of EMS responders and firefighters to the Covid 19 illness is much higher in relation to the general population. The transmission of microorganisms, such as viruses, from an infected patient to a first responder can occur in various ways. For example, coughing, sneezing, breathing and speaking can produce the airborne transmission of microorganisms. Coughing and sneezing, for instance, can produce relatively large respiratory droplets having a diameter of from about 10 microns up to about 1000 microns. Simply breathing and speaking also produces respiratory droplets, typically in a range of from about 0.8 microns to about 5.5 microns. These respiratory droplets are relatively invisible and create significant risk to those trying to help the infected. In addition to airborne transmission, the transmission of microorganisms can also occur through surfaces. For example, clothing made from textiles can provide a very large hosting surface for microorganisms. The Coronavirus, from instance, showed a relatively long survival time on cotton fabrics, particularly up to seven days. The Coronavirus can also survive on synthetic fibers for up to two days.
In order to impart water resistance, fabric materials can be treated with a variety of durable water resistant treatments. These durable water resistant treatments offer a degree of protection against, among other things, respiratory droplets containing bacterial and viral actives. Generally, durable water resistant treatments oftentimes employ a variety of fluorocarbons to impart oil resistance. However, government regulations may require the removal of fluorocarbons from fabric materials.
In view of the above, a need exists for improved protective garments for health care professionals and emergency responders. More particularly, a protective garment is needed that is substantially fluorocarbon free and can protect the wearer against airborne droplets containing pathogens, particularly viruses. More particularly, a need exists for a protective garment that not only hinders penetration of respiratory water droplets carrying a virus but also optionally provides antiviral features.
In general, the present disclosure is directed to protective garments that can provide barrier protection against all different types of fluids and microorganisms, including bacteria and viruses. The present disclosure is also directed to protective garments that are substantially fluorocarbon free. In addition, the present disclosure is directed to a fabric material that is used to produce the protective garments described above.
In one embodiment, for instance, the present disclosure is directed to a protective garment comprising a fabric material. The fabric material, for example, can comprise a woven fabric, a knitted fabric, a nonwoven fabric, or combinations thereof. The fabric material can also contain a film layer if desired. In accordance with the present disclosure, the fabric material includes a water resistant treatment in combination with an oil resistant treatment. The water resistant treatment is substantially fluorocarbon free and contains a durable water resistant composition. The fabric material further includes a first side and a second and opposite side. The oil resistant treatment includes an elastomeric coating located on the first side of the fabric material.
Combining the durable water resistant composition with the oil resistant treatment provides various advantages and benefits. The durable water resistant composition, for instance, prevents respiratory vapors from penetrating the fabric. The oil resistant treatment, on the other hand, acts as a barrier to prevent oil from penetrating the fabric.
In one aspect, the elastomeric coating can comprise a silicone polymer, a polyurethane polymer, or a neoprene polymer. The coating can be microporous or continuous. In another aspect, for instance, the garment can include an exterior side surface and an opposite body-facing side surface. The elastomeric coating can be adjacent to the body-facing surface or on the exterior side. In one aspect, the elastomeric coating can further comprise a curing agent.
In one aspect, the elastomeric coating can comprise a polydiorganosiloxane in combination with a catalyst. The elastomeric coating can further comprise, for instance, an adhesion promoter.
In one aspect, the protective garment can further include an antimicrobial treatment containing an antiviral composition. The antiviral composition, which includes at least one antiviral agent, is designed to destroy microorganisms and/or prevent the growth of microorganism.
In one aspect, the antimicrobial agent can comprise silver ions, copper ions, or a mixture of silver and copper ions. The antimicrobial agent, for instant, can be any suitable ion-exchange type material. In one aspect, the antimicrobial agent can include a ceramic carrier for ion-exchanged metal ions. The ceramic carrier can comprise a zeolite. In another aspect, the antiviral agent can include a biguanide, quat-silane, chitosan, or zinc pyrithione. In addition to one or more antiviral agents, the antiviral composition can also contain various other components, such as an emulsifier and/or a binder.
In general, any suitable durable water resistant composition can be combined with the antimicrobial composition as long as the two compositions are compatible. Additionally, the water resistant and antimicrobial treatment, for example, can impregnate the fabric as opposed to forming a distinct coating layer on the surface of the fabric.
The durable water resistant composition is substantially fluorocarbon free. For example, the fabric material can contain one or more fluorocarbons, in one embodiment, in an amount less than about 1000 ppm, such as in an amount less than about 500 ppm, such as in an amount less than about 100 ppm, such as in an amount less than about 5 ppm, such as in an amount less than about 100 ppb, such as in an amount less than about 60 ppb, such as even in an amount less than about 25 ppb.
In one aspect, the durable water resistant composition can contain at least one polyurethane polymer. The polyurethane polymer, for instance, may be a polyester/ether polyurethane polymer, such as an anionic aliphatic polyester/ether polyurethane. In one embodiment, the durable water resistant composition includes a first polyurethane polymer as described above combined with a second polyurethane polymer. The second polyurethane polymer may comprise a blocked isocyanate. The weight ratio between the first polyurethane polymer and the second polyurethane polymer can be from about 5:1 to about 1:2, such as from about 3:1 to about 1.5:1.
In addition to at least one polyurethane polymer, the fluorocarbon-free durable water resistant composition can contain various other components and ingredients. In one embodiment, for instance, the durable water resistant composition can contain a softener. The softener may comprise a polyalkylene polymer, such as a polyethylene polymer. The durable water resistant composition can also contain an acrylic polymer, a silicone polymer, a denderimer, a wax such as a paraffin wax, and mixtures thereof. In one aspect, the durable water resistant composition contains a hyperbranched polymer, such as a hyperbranched silicone polymer.
Protective garments made in accordance with the present disclosure can be used in all different types of applications. For example, the protective garment can be a medical garment, a lab coat, a public service uniform, or a fire-safety garment, such as a fireman's turnout coat. Medical garments include isolation gowns and surgical gowns. Especially when used in the medical field, the protective garment can provide a certain level of protection in accordance with standards established by the Association for the Advancement of Medical Instrumentation (AAMI). The AAMI, for instance, has promulgated different levels for barrier performance and has published guidelines for barrier classification. Protective garments made according to the present disclosure, for instance, can be designed to maintain a Level 1 protection, a Level 2 protection, a Level 3 protection, and even a Level 4 protection. The Level 4 protection garments, for instance, can, in one aspect, include a fabric material that includes a film layer positioned in between at least a first outer fabric layer and optionally a second outer fabric layer. Protective garments made according to the present disclosure can also have the above ratings and be durable. For instance, the protective garments can maintain a desired AAMI rating even after 60 laundry cycles, such as after 75 laundry cycles, such as after 100 laundry cycles.
Especially when being used to produce medical garments, the fabric used to make the protective garment can be a woven fabric made from polyester yarns. The polyester yarns can comprise multifilament yarns. In one aspect, the woven fabric can contain from about 80 to about 180 warp yarns per inch and from about 60 to about 110 fill yarns per inch. The basis weight of the fabric can be from about 1.8 osy to about 3.2 osy, such as from about 2.3 osy to about 2.8 osy. The fabric can also be calendered in order to improve the barrier properties of the fabric. In one aspect, the protective garment can be made from a single layer of the fabric.
In an alternative embodiment, the protective garment may be designed for fire service applications and may contain inherently flame resistant fibers. The inherently flame resistant fibers, for instance, may include para-aramid fibers, meta-aramid fibers, polybenzimidazole fibers, and mixtures thereof. In one embodiment, the outer shell material contains inherently flame resistant fibers in an amount of at least about 60% by weight. The fabric material can be formed from yarns of the inherently flame resistant fibers. The yarns can be multifilament yarns, spun yarns, stretch-broken yarns, monofilament yarns, and mixtures thereof. In one embodiment, the fabric material can be made from a combination of spun yarns and multifilament yarns.
Due to the presence of the durable water resistant composition, fabric materials made according to the present disclosure can display excellent water resistant properties. For instance, the fabric material can maintain a water absorption of less than about 15%, such as less than about 10%, after 5 laundry cycles or after 10 laundry cycles. The fabric material can also maintain a spray rating of at least 70, such as at least 80, such as at least 90, after 10 laundry cycles.
In addition to water repellency, fabric materials made according to the present disclosure also display excellent oil and fuel resistance, especially due to the elastomeric coating. For instance, fabrics made according to the present disclosure can pass ISO Test 6530 directed to the protection against liquid chemicals when tested against, for instance, O-xylene.
Fabrics made according to the present disclosure can also have excellent air permeability properties. For example, fabrics made according to the present disclosure can have an air permeability of greater than about 0.2 cfm, such as greater than about 0.3 cfm, such as greater than about 0.4 cfm, such as greater than about 0.5 cfm, such as greater than about 0.6 cfm, such as greater than about 0.7 cfm, such as greater than about 0.8 cfm, such as greater than about 0.9 cfm, such as greater than about 1 cfm, such as greater than about 1.2 cfm, such as greater than about 1.4 cfm, such as greater than about 1.6 cfm, such as greater than about 1.8 cfm, such as greater than about 2.0 cfm, such as greater than about 2.2 cfm, such as greater than about 2.4 cfm, such as greater than about 2.6 cfm, and generally less than about 10 cfm, such as less than about 8 cfm, such as less than about 6 cfm, such as less than about 4 cfm. The above permeability characteristics can be obtained for lighter weight fabrics having a basis weight of from about 2 osy to about 5 osy and for heavier basis weight fabrics having a basis weight of from about 5 osy to about 9 osy.
In one aspect, both the durable water resistant composition and an antiviral composition can be combined together and applied to the fabric material. In other embodiments, however, the compositions can be applied to the fabric material separately. The water resistant and antimicrobial treatment can be applied to the fabric material as a spray or the fabric material can be dipped into a bath containing the water resistant and antimicrobial treatment. The treatment can also be applied to the fabric material as a foam.
The water resistant and antimicrobial treatment can be specially formulated in order to make sure that all of the components are compatible. In one embodiment, for instance, the water resistant and antimicrobial treatment are nonionic. The water resistant and antimicrobial treatment can be applied to the fabric material at a solid add on level of from about 0.5% to about 5% by weight, such as from about 1% to about 3% by weight.
Other features and aspects of the present disclosure are discussed in greater detail below.
A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
The following definitions and procedures are offered in order to better describe and quantify the performance of protective garments and fabrics made according to the present invention in comparison to prior art constructions.
The teachings of the present disclosure are particularly well suited to constructing protective garments for the medical industry.
When used in the healthcare industry, for example, the protective garment of the present disclosure can be rated according to the Association for the Advancement of Medical Instrumentation (AAMI). The current AAMI standard is described in “Liquid Barrier Performance and Classification of Protective Apparel and Drapes Intended for Use in Health Care Facilities,” ANSI/AAMI PB70:2012. This AAMI standard helps to preserve the sterile field and protect health care workers during surgery and other health care procedures during which exposure to blood, body fluids and other potential infectious material might occur. This AAMI standard establishes a system of classification and associated minimum requirements for protective apparel such as gowns and drapes used in health care facilities based on their liquid barrier performance.
The present AAMI standard for liquid barrier performance is provided in the following table:
As used herein, a fabric spray rating refers to a rating a fabric or a material receives according to AATCC TM22-2017. In general, a spray test measures the resistance of a material to wetting by water.
According to the present invention, the following is the procedure used to determine the spray rating of a material.
The following standardized water repellency test determines a material's resistance to wetting by aqueous liquids. In general, drops of a water-alcohol mixture of varying surface tensions are placed on the surface of the material and the extent of surface wetting is determined visually. The higher the rating a material receives is an indication of the material's resistance to staining by water-based substances. The composition of standard test liquids is as follows:
The water repellency procedure is as follows:
Laundering is preferably performed in an automatic washer, followed by drying in an automatic dryer. The following laundering test is used to determine the fabric's ability to withstand laundering. Typically, after laundering, the fabric is then subjected to the above-described spray test, water repellency test, and oil repellency test.
The test pieces and dummy load are placed in the washer and the machine is started. One ounce of TIDE (Proctor & Gamble) detergent is added while the washer is filling with soft water. If the water hardness is greater than 5 ppm, CALGON water softener (Nalco) in the amount specified by the manufacturer is added to soften the water.
The following water absorption test is for determining the resistance to water absorption of a fabric or material. The test is based upon NFPA 1971-2018, 8-25. In particular, the water absorption test is conducted according to the above-identified test method after the fabric or material has been subjected to five laundry cycles in accordance with NFPA 1971, 8-1.2 (or AATCC TM135-2018-1, V, Ai).
According to the present invention, the following is the procedure used to determine the water absorption rating of a material.
herein W is the weight of the wet sample and O is the weight of the dried sample. The water absorption rating of the sample is the average of the results obtained from the three specimens tested.
The following test also measures the water-repellent efficacy of finishes applied to fabrics, because the test subjects the treated fabrics to dynamic conditions similar to those often encountered during actual use. The test conforms to AATCC TM70-2015.
According to the present invention, the following is the procedure used to determine the dynamic water absorption rating of a material.
WA=(W−C)/C×100
As used herein, the air permeability of a fabric (e.g. coated fabric) is tested according to ASTM Test D737 (2018).
Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.
It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.
In general, the present disclosure is directed to a protective garment that is particularly well suited to protecting the user from fluids and providing an impenetrable barrier to many liquids. In addition, protective garments made in accordance with the present disclosure can have antimicrobial properties and can be particularly adapted to deactivate viruses and/or destroy microorganisms including bacteria that come in contact with the protective garment. In accordance with the present disclosure, the protective garments are made from a fabric material that includes a water resistant treatment and an oil resistant treatment. The water resistant treatment contains a durable water resistant composition that is substantially fluorocarbon free and is applied as a finish that is impregnated into the fabric material. The oil resistant treatment includes an elastomeric coating that may comprise a silicone polymer or a polyurethane polymer. The combined properties of the water resistant treatment and the oil resistant treatment substantially hinder penetration of respiratory water droplets that may contain a pathogen, such as a virus. Additionally, when the fabric further includes an antimicrobial treatment, the fabric provides antiviral features once the fabric material comes into contact with a virus. Of particular advantage, treated fabric materials in accordance with the present disclosure also have excellent durability and can display the above properties after multiple laundry cycles.
As learned from the recent Coronavirus pandemic, pathogens, particularly viruses, can remain in aerosol for hours and transmission through respiratory droplets is particularly problematic. In addition, microorganisms such as viruses, can survive even up to a few days on a fabric surface. Consequently, protective garments are needed especially for first responders and healthcare personnel that are day to day on the front lines of treating patients infected with diseases causes by microorganisms. In fact, during the pandemic, the number of first responders that have been infected with the Coronavirus is alarming. Protective fabrics and protective garments made according to the present disclosure are capable of substantially preventing the penetration of respiratory droplets through the use of a water resistant coating and an oil resistant coating.
Protective garments made in accordance with the present disclosure can be used in all different types of fields and applications. The protective garments, for instance, can be used by healthcare personnel and/or by patients and can include daily medical wear or can include more specialized garments, such as gowns, lab coats, and the like. Protective garments made in accordance with the present disclosure can also include fire safety garments and apparel. Such protective garments can include footwear, trousers, jackets, coats, shirts, headwear, gloves, and the like. The protective garment can be a one-piece jumpsuit or can comprise a uniform, such as a military garment, tactical garment, industrial garment, police garment, battle dress uniform, and the like.
As described above, protective garments in accordance with the present disclosure are made from a fabric material that includes a water resistant and an oil resistant treatment. The water resistant treatment contains a durable water resistant composition that is substantially fluorocarbon free. The oil resistant treatment includes an elastomeric coating that may comprise a silicone polymer. Optionally, the fabric material can further include an antimicrobial treatment containing an antiviral composition. When the antimicrobial treatment is used, although the antimicrobial treatment and the water resistant treatment can be applied to the fabric material separately, in one aspect, both treatments can be combined together and applied to the fabric material in one step, such as through a dipping process.
The durable water resistant treatment can be an impregnation treatment that is impregnated into the fabric material (present over the thickness of the fabric material) and is to be distinguished from a coating. The elastomeric coating, on the other hand, forms a coating on the fabric, such as on the surface of the fabric and may not be present over the entire thickness of the fabric material.
In general, the elastomeric coating of the oil resistant treatment is formed from an elastomeric polymer optionally in combination with a curing agent. In one particular embodiment, the coating can comprise a silicone rubber, a polyurethane elastomer, or a neoprene rubber.
In general, any suitable elastomeric composition may be used in the oil resistant treatment. When applying a silicone rubber to the first side or second side of the fabric material, the silicone rubber composition can vary. In one embodiment, for instance, the elastomeric composition may contain a polydiorganosiloxane in combination with a catalyst and optionally an adhesion promoter.
In one embodiment, the silicone composition comprises a polydiorganosiloxane containing at least two alkenyl groups per molecule; a polyorganohydrogenosiloxane containing at least two hydrogen atoms linked to silicon in each molecule; a metallic catalyst of the platinum group; an adhesion promoter that may include an epoxy-functional organosilicon compound; a mineral filler; a resin polyorganosiloxane; and optionally a compound that is useful as a curing inhibitor.
In another embodiment, the silicone composition comprises a polydiorganosiloxane containing at least two alkenyl groups per molecule; a polyorganohydrogenosiloxane containing at least two hydrogen atoms linked to silicone in each molecule; a silane containing a methacrylic function; an epoxyalkoxysilane; an aluminium chelate; and a metallic catalyst of the platinum group.
In still another embodiment, the elastomeric coating composition comprises at least one polyorganosiloxane containing, per molecule, at least two C2-C6 alkenyl groups linked to silicon; at least one polyorganosiloxane containing, per molecule, at least two hydrogen atoms linked to silicon; a catalytically effective amount of at least one catalyst, composed of at least one metal belonging to the platinum group; an adhesion promoter; optionally, a mineral filler; optionally, at least one curing inhibitor; and optionally, at least one polyorganosiloxane resin, in which composition the adhesion promoter may comprise a ternary combination of the following ingredients: at least one alkoxylated organosiloxane containing, per molecule, at least one C2-C6 alkenyl group; at least one organosilicon compound comprising at least one epoxy radical; and at least one metal chelate M and/or a metal alkoxide of general formula: M(OJ)n, with n=valency of M and J=linear or branched C1-C8 alkyl, M being chosen from the group formed by: Ti, Zr, Ge, Li, Mn, Fe, Al and Mg.
In one particular embodiment, the elastomeric composition comprises a polyorganosiloxane that may be cured. The composition, for instance, may comprise at least one polyorganosiloxane (I) containing, per molecule, at least two C2-C6 alkenyl groups linked to silicon; at least one polyorganosiloxane (II) containing, per molecule, at least two hydrogen atoms linked to silicon; a catalytically effective amount of at least one catalyst (III), composed of at least one metal belonging to the platinum group; at least one adhesion promoter (IV); an additive system (B) for improving the combing strength and the tear strength, the constituents of which are added sequentially or simultaneously, comprising a mixture formed from: (1) at least one polyorganosiloxane resin (V) present at up to 60% by weight relative to the total weight of the mixture and optionally mixed with at least one polyorganosiloxane serving as diluent, and (2) calcium carbonate (CaCO3) present at up to 30% by weight relative to the total weight of the mixture; optionally, at least one curing inhibitor (VI); optionally, at least one coloration additive (VII); and optionally, at least one additive (VIII) for improving the fire resistance.
In one embodiment, one or more polyorganosiloxane resins may be present in the coating composition in an amount from about 5% to about 60% by weight, such as in an amount from about 10% to about 30% by weight.
The polyorganosiloxane used to produce the coating composition may comprise: (i) siloxyl units of formula:
This polydiorganosiloxane (I) may have a viscosity at least equal to 200 mPa·s and preferably less than 200,000 mPa·s.
All the viscosities concerned in the present specification correspond to a dynamic viscosity magnitude that is measured, in a manner that is known per se, at 25° C.
The polyorganosiloxane (I) may be formed solely from units of formula (I-1) or may contain, in addition, units of formula (I-2). Similarly, it may have a linear, branched, cyclic or network structure. Z is generally chosen from methyl, ethyl and phenyl radicals, 60 mol % (or in numerical terms) at least of the radicals Z being methyl radicals. Examples of siloxyl units of formula (I-1) are vinyldimethylsiloxyl, vinylphenylmethylsiloxyl, vinylmethylsiloxyl and vinylsiloxyl units.
Examples of siloxyl units of formula (I-2) are the units SiO4/2, dimethylsiloxyl, methylphenylsiloxyl, diphenylsiloxyl, methylsiloxyl and phenylsiloxyl. Examples of polyorganosiloxanes (I) are linear and cyclic compounds, for instance: dimethyl-polysiloxanes containing dimethylvinylsilyl end groups, (methylvinyl)(dimethyl)-polysil-oxane copolymers containing trimethylsilyl end groups, (methylvinyl)(dimethyl)-polysiloxane copolymers containing dimethylvinylsilyl end groups and cyclic methylvinylpolysiloxanes.
Advantageously, the polyorganosiloxane (II) comprises siloxyl units of formula:
in which the groups L have the same meaning as above and g is equal to 0, 1, 2 or 3.
The dynamic viscosity of this polyorganosiloxane (II) is at least equal to 10 mPa·s and preferably between 20 and 1000 mPa·s. The polyorganosiloxane (II) may be formed solely from units of formula (II-1) or may also comprise units of formula (II-2). The polyorganosiloxane (II) may have a linear, branched, cyclic or network structure. The group L has the same meaning as the group Z above. Examples of units of formula (II-1) are H(CH3)2SiO1/2, HCH3SiO2/2 and H(C6H5)SiO2/2.
The examples of units of formula (II-2) are the same as those given above for the units of formula (I-2).
Examples of polyorganosiloxanes (II) are linear and cyclic compounds, for instance: dimethylpolysiloxanes containing hydrogenodimethylsilyl end groups; copolymers containing (dimethyl)(hydrogenomethyl)polysiloxane units containing trimethylsilyl end groups; copolymers containing (dimethyl)(hydrogenomethyl)polysiloxane units containing hydrogenodimethylsilyl end groups; hydrogenomethylpolysiloxanes containing trimethylsilyl end groups; cyclic hydrogenomethylpolysiloxanes.
The compound (II) may optionally be a mixture of a dimethylpolysiloxane containing hydrogenodimethylsilyl end groups and of a polyorganosiloxane bearing at least three functions SiH (hydrogenosiloxyle).
The ratio of the number of hydrogen atoms linked to silicon in the polyorgano-siloxane (II) to the total number of groups containing alkenyl unsaturation of the polyorganosiloxane (I) and of the resin (V) is between 0.4 and 10 and preferably between 0.6 and 5.
The bases of silicone polyaddition compositions may comprise only linear polyorganosiloxanes (I) and (II), for instance those described in patents: U.S. Pat. Nos. 3,220,972, 3,697,473 and 4,340,709 or may comprise both branched or network polyorganosiloxanes (I) and (II), for instance those described in patents: U.S. Pat. Nos. 3,284,406 and 3,434,366.
According to one particular embodiment, the following are used: at least one linear polyorganosiloxane (I) comprising chains formed from units of formula (I-2) in which c=2, blocked at each of their ends with units of formula (I-1) in which a=1 and b=2, and at least one linear polyorganosiloxane (II) comprising in its structure at least three hydrogen atoms linked to silicon, located in the chains and/or at chain ends; and even more particularly: at least one linear polyorganosiloxane (I) comprising chains formed from units of formula (I-2) in which c=2, blocked at each of their ends with units of formula (I-1) in which a=1 and b=2, and at least one linear polyorganosiloxane (I) comprising chains formed from units of formula (II-1) in which d=1 and e=1 and optionally units of formula (II-2) in which g=2, blocked at each of their ends with units of formula (II-1) in which d=1 and e=2.
In one embodiment, a silicone rubber composition is used that has a viscosity of greater than about 5000 mPa·s, such as greater than about 8000 mPa·s, such as greater than about 10,000 mPa·s, such as greater than about 12,000 mPa·s. The composition can generally have a viscosity of less than about 70,000 mPa·s, such as less than about 60,000 mPa·s, such as less than about 50,000 mPa·s, such as less than about 40,000 mPa·s, such as less than about 30,000 mPa·s, such as less than about 25,000 mPa·s, such as less than about 20,000 mPa·s. The silicon rubber can have a shore A hardness of greater than about 25, such as greater than about 30, such as greater than about 35, such as greater than about 40, such as greater than about 45. The shore A hardness is generally less than about 80, such as less than about 70, such as less than about 60.
Alternatively, The silicone coating applied to the fabric can be a two-part mixture containing a silicone oil and a catalyst. The silicone can be a siloxane (e.g. polydimethylsiloxane) and the mixture can have a liquid viscosity at room temperature. For instance, the viscosity of the mixture can be less than about 20,000 mPa at 23° C., such as less than about 10,000 mPa, such as less than about 5,000 mPa, and greater than about 500 mPa. The silicone mixture can be knife coated onto the fabric.
In addition to silicone rubber, various other cured rubber coatings may be applied to the fabric substrate. For instance, the elastomeric coating may comprise a neoprene or a chloroprene coating.
In one aspect, the coating can be a polyurethane polymer. The polyurethane polymer, for example, may form a microporous coating on the fabric material. The polyurethane coating can have a thickness of greater than about 20 microns, such as greater than about 30 microns, such as greater than about 35 microns. The thickness can be less than about 200 microns, such as less than about 100 microns, such as less than about 50 microns. The above thickness ranges can also apply to coatings made from silicone, neoprene or chloroprene polymers.
The elastomeric coating composition can be applied to either side of the fabric substrate using any suitable method or technique and cured. In one embodiment, the coating composition is applied to the fabric substrate using a knife over roll method. In an alternative embodiment, a knife over air method may be used. In still another embodiment, the coating composition can be applied to a transfer roll which then transfers the coating composition to a surface of the fabric substrate.
The amount of the elastomeric coating applied to the fabric can depend upon numerous factors. In one embodiment, the dried coating weight can be from about 1 gsm to about 50 gsm including all increments of 1 gsm therebetween. The dried coating weight can be greater than about 3 gsm, such as greater than about 5 gsm, such as greater than about 7 gsm, such as greater than about 10 gsm, such as greater than about 12 gsm, such as greater than about 15 gsm, and generally less than about 30 gsm, such as less than about 20 gsm, such as less than about 15 gsm.
The fabric material may additionally include an antimicrobial treatment that optionally contains an antiviral composition. Alternatively, the antiviral composition can be incorporated into the elastomeric coating. In general, many durable water resistant compositions and antiviral compositions are relatively incompatible and cannot remain together as a stable liquid. Instead, due to the incompatibility of the components, the liquid can form a precipitate, can become cloudy, or can otherwise simply not bind to a fabric substrate. The water resistant and optional antimicrobial treatment of the present disclosure, however, has been specially formulated in order to remain stable. In fact, it was discovered that the durable water resistant composition can actually promote the uniform application of the antiviral composition and assist or facilitate binding of the antiviral agent to fibers contained in the fabric material.
The antiviral composition that may optionally be included in the fabric material can contain one or more antiviral agents. In one aspect, the antiviral agent comprises a metal ion. In one aspect, for example, a metal ion containing ion-exchange agent is used. Alternatively, the antiviral agent can be a water soluble salt or water soluble particles containing free metal ions. Metal ions that may be included in the antiviral agent include, for instance, silver, copper, zinc, gold, iron, cobalt, nickel, manganese, antimony, bismuth, barium, cadmium, chromium, and mixtures thereof. In one aspect, the metal ions are silver, copper, gold, zinc and combinations thereof. In one particular embodiment, for instance, the antiviral agent can comprise silver ions alone or in combination with copper ions, zinc ions, or both copper ions and zinc ions. Other antimicrobial agents may include, for instance, biguanides, quat-silane, chitosan, or zinc pyrithione.
Ion-exchange type antiviral agents are typically characterized as comprising an ion-exchange capable ceramic particle having ion-exchanged antiviral metal ions, i.e., the antiviral metal ions have been exchanged for (replaced) other nonantiviral effective ions in and/or on the ceramic particles. While these materials may have some surface adsorbed or deposited metal, the predominant antiviral effect is as a result of the ion-exchanged antiviral metal ions released from within the ceramic particles themselves.
Antiviral ceramic particles include, but are not limited to zeolites, calcium phosphates, hydroxyapatite, zirconium phosphates and other ion-exchange ceramics. These ceramic materials come in many forms and types, including natural and synthetic forms. For example, the broad term “zeolite” refers to aluminosilicates having a three dimensional skeletal structure that is represented by the formula: XM2/nO—Al2O3-YSiO2-ZH2O wherein M represents an ion-exchangeable ion, generally a monovalent or divalent metal ion; n represents the atomic valence of the (metal) ion; X and Y represent coefficients of metal oxide and silica, respectively; and Z represents the number of water of crystallization. Examples of such zeolites include A-type zeolites, X-type zeolites, Y-type zeolites, T-type zeolites, high-silica zeolites, sodalite, mordenite, analcite, clinoptilolite, chabazite and erionite.
Generally speaking, the ion-exchange type antiviral agents that can be used in the practice of the present invention are prepared by an ion-exchange reaction in which non-antiviral ions present in the ceramic particles, for example sodium ions, calcium ions, potassium ions and iron ions in the case of zeolites, are partially or wholly replaced with the antiviral metal ions, for example, copper and/or silver ions. The combined weight of the antiviral metal ions will be in the range of from about 0.1 to about 35 wt. %, preferably from about 1 to 25 wt. %, more preferably from about 2 to about 20 wt. %, most preferably, from about 2.5 to 15 wt. %, of the ceramic particle based upon 100% total weight of ceramic particle. Where the ceramic particles include two or more different antiviral metal ions, each antiviral metal ion is typically present in and amount of from about 0.1 to about 25 wt %, preferably from about 0.3 to about 15 wt. %, most preferably from about 2 to about 10 wt. % of the ceramic particle based on 100% total weight of the ceramic particle.
In one aspect, the particles can contain both silver ions in combination with copper ions. In these instances, the weight ratio of silver to copper ions is from 1:10 to 10:1, preferably from 5:1 to 1:5, most preferably from 2.5:1 to 1:2.5. In an especially preferred embodiment, the ceramic particle contains from about 0.3 to about 15 wt. % of silver ions and from about 0.3 to about 15 wt, % of copper ions in a weight ratio of 5:1 to 1:5. Exemplary compositions are disclosed in US 2006/0156948A1 and 2008/0152905A1, both of which are incorporated herein by reference in their entirety.
The antiviral ceramic particles may also contain other ion-exchanged ions for various purposes, particularly ions that improve color stability of the fabrics and/or overall stability and/or ion release characteristics of ceramic particles. An exemplary and preferred other ion is ammonium ion.
The preferred antiviral ion-exchange agents are the antiviral aluminosilicates, specifically the zeolites. A number of different grades and types of antiviral zeolites are commercially available from Sciessent, LLC of Wakefield, Mass., US under the Ag10N trademark. These include the following grades: AW10D—about 0.6% silver; AG10N and LG10N—about 2.5% silver; AJ10D— about 2.5% silver, 14% zinc, and 0.5%-2.5% ammonium ions; and AC10D—about 6.0% copper and about 3.5% silver: These are based on a type A zeolite of a mean average diameter of about 3μ, 10μ in the case of the LG grade.
The above metal ions are described as having antiviral properties. It should be understood, however, that the metal ions are also very effective against all different types of microorganisms, including bacteria and/or fungi. In this regard the metal ions may also be referred to as antimicrobial agents.
The one or more antiviral agents as described above can be applied to the fabric material in accordance with the present disclosure in an amount sufficient to destroy and kill microorganisms that come in contact with the fabric material, including the Coronavirus. In general, the one or more antimicrobial agents are applied to the fabric material in an amount from about 0.05 gsm to about 2 gsm, including all increments of 0.05 gsm there between. For instance, the one or more antiviral agents can be applied to a fabric material in an amount greater than about 0.1 gsm, such as greater than about 0.3 gsm, such as greater than about 0.5 gsm, such as greater than about 0.7 gsm, and generally less than about 1.5 gsm, such as less than about 1.3 gsm, such as less than about 1 gsm, such as less than about 0.7 gsm.
The antiviral composition which may optionally be contained in the fabric can contain one or more antiviral agents in combination with a binder. Binders that may be used include polyurethanes and/or acrylics. In accordance with the present disclosure, a binder can be selected that is compatible with the durable water resistant composition. For example, a particular binder can be selected that is cationic, nonionic or even anionic depending upon the components of the remainder of the treatment composition. In one embodiment, for instance, an acrylic based binder is used. The binder can be present in the antiviral composition generally in an amount from about 0.1% by weight to about 60% by weight, including all increments of 1% by weight therebetween. For example, the binder can be present in the antimicrobial composition in an amount greater than about 1% by weight, such as in an amount greater than about 3% by weight, such as in an amount greater than about 5% by weight and generally in an amount less than about 40% by weight, such as in an amount less than about 30% by weight, such as in an amount less than about 20% by weight, such as in an amount less than about 15% by weight.
In one particular aspect, the optional antimicrobial composition may contain zeolite particles containing silver in an amount from about 3% to about 15% by weight, such as in an amount from about 7% to about 12% by weight. The antiviral composition can also contain zeolite particles containing both silver and copper ions generally in an amount from about 6% by weight to about 20% by weight, such as in an amount from about 11% by weight to about 17% by weight. The antiviral composition can also contain an acrylic polymer binder generally in an amount from about 12% to about 35% by weight, such as in an amount from about 22% to about 28% by weight. Optionally, the antiviral composition can also contain a polyurethane resin in relatively minor amounts, such as in amounts from about 0.5% to about 3% by weight. The remainder of the antiviral composition can comprise water alone or in combination with a glycol, such as propylene glycol. Propylene glycol, for instance, can be present in the antimicrobial composition in an amount from about 0.5% to about 4% by weight.
The durable water resistant composition of the present disclosure prevents liquids from being absorbed by the fabric material. However, the durable water resistant composition of the present disclosure is substantially fluorocarbon free, leaving the fabric susceptible to oil absorption. The oil resistant treatment of the present disclosure imparts a high degree of oil resistance to the fabric material, as well as resistance to other solvents, and can make the fabric material more abrasion-resistant.
The fluorocarbon free durable water resistant composition contains a binder and/or an extender combined with various other ingredients and components. For instance, the durable water resistant composition can also include a softener, a repelling agent, or both a softener and a repelling agent.
The binder contained in the durable water resistant composition, in one embodiment, can comprise a polyurethane polymer. Of particular advantage, the polyurethane polymer can be water-based and thus can be applied to the fabric in an aqueous dispersion. In one embodiment, the polyurethane polymer is an anionic polyurethane. The polyurethane polymer can also be an aliphatic polyurethane. In one particular embodiment, the polyurethane polymer that makes up the binder is a polyester/ether polyurethane polymer, such as an aliphatic polyester/ether polyurethane polymer.
Optionally, the above binder can be combined with an extender. The extender may also comprise a polyurethane polymer. Thus, in one embodiment, the durable water resistant composition includes a first polyurethane polymer combined with a second polyurethane polymer. The extender, for instance, can comprise a modified polyurethane polymer. For instance, the extender may be a blocked isocyanate, such as an oxime-blocked isocyanate. The extender can be cationic or nonionic. The extender is for further increasing water and oil resistance.
In addition to a binder and/or an extender, in one embodiment, the durable water resistant composition can further include a softener. The softener, for instance, may comprise an emulsion of a polyalkylene polymer. The softener is generally nonionic. In one embodiment, the softener is a polyethylene polymer, such as a lower molecular weight polyethylene polymer.
In one embodiment, the durable water resistant composition may also contain a repelling agent. The repelling agent may include an acrylic polymer alone or in combination with a wax, such as a paraffin wax. In one embodiment, the repelling agent may include a polyacrylate that also serves as a binder.
Each of the above ingredients can be combined with water and optionally a wetting agent, such as isopropyl alcohol for application to a fabric. The relative amounts of each component can vary depending on the particular formulation. In one embodiment, for instance, the binder or first polyurethane can be present in relation to the extender or second polyurethane in a weight ratio of from about 5:1 to about 1:2, such as in a weight ratio of from about 4:1 to 1:1. In one embodiment, the binder and extender are present in a weight ratio of from about 3:1 to about 1.5:1 based on the dried weight of the finish. The repelling agent can be present in amounts greater than the binder or the extender. For instance, the weight ratio (based on the dried weight of the finish) between the binder or extender and the repelling agent can be from about 3:1 to about 1:8, such as from about 1:1 to about 1:5, such as from about 1:1.5 to about 1:3.
When included in the formulation, the softener can generally be present in amounts less than the binder, the repelling agent or the extender. For example, in one embodiment, the softener can be present in relation to the binder in a weight ratio of from about 1:1 to about 1:4, such as from about 1:1.5 to about 1:3.
As described above, the durable water resistant composition and the optional antiviral composition can both contain a binder. In one aspect, only a single binder can be used in the combined formulation. In other embodiments, however, multiple binders can be used as desired.
As described above, the durable water resistant composition and the optional antiviral composition can be applied to the fabric material separately. Efficiencies and various advantages can be obtained, however, if the durable water resistant composition and the optional antiviral composition are combined together and applied to the fabric material at the same time as a single water resistant and antimicrobial treatment. Prior to applying the water resistant and optional antimicrobial treatment, the fabric material can optionally be scoured using, for instance, an alkaline solution. After being scoured, the fabric material can be put on a tenter frame, dried, and heat seat. For instance, after scouring, the fabric material can be dried so that the moisture level is substantially equivalent to the natural moisture level of the fibers used to make the fabric material. For instance, the moisture level can be less than about 10% by weight, such as less than about 7% by weight, and generally greater than about 3% by weight.
After the fabric material has been dried and heat set, the water resistant and the optional antimicrobial treatment can be applied to at least one side of the fabric material. Although the treatment can be sprayed onto the fabric material as a liquid or foam or printed onto the fabric material, in one aspect, the fabric material is dipped into a bath containing the water resistant and antimicrobial treatment.
In one aspect, when applying a water resistant and antimicrobial treatment that is fluorocarbon-free, the composition can contain the following as examples (remainder water):
The amount of the water resistant treatment applied to the fabric material will depend upon the particular formulation and the particular application. The dry add on can be greater than about 0.5% by weight, such as greater than about 1% by weight, such as greater than about 1.5% by weight, such as greater than about 2% by weight, such as greater than about 2.5% by weight, such as greater than about 3% by weight, and generally less than about 7% by weight, such as less than about 5% by weight, such as less than about 4% by weight, such as less than about 3.5% by weight.
After the water resistant treatment is applied to the fabric material, the fabric material is then heated to a temperature sufficient for the treatment composition to dry and/or cure. The fabric material then can be used in constructing various protective garments in accordance with the present disclosure.
The manner in which the durable water resistant treatment and the elastomeric coating are applied to the fabric material and garment can vary. In one aspect, the coating is applied to the body-side or interior surface of the fabric material. Alternatively, the coating is applied to the exterior surface of the fabric material. The durable water resistant treatment can be applied to the opposite side of the fabric material and, as described above, can impregnate the fabric. The anti-viral treatment can be combined with the coating material and/or combined with the durable water resistant treatment. Alternatively, the anti-viral treatment can be applied separately to the fabric materials.
Fabric materials treated according to the present can have various liquid resistant properties, can optionally have antimicrobial properties including antiviral properties, and can provide a barrier to multiple fluids and liquids that the wearer may contact.
In one embodiment, the fabric material is used to construct protective garments for use in the medical industry. In this application, the protective garment can protect the user from blood, other body fluids, saline solutions and other fluids from penetrating or striking through the fabric. The fabric material can also provide antimicrobial properties in addition to preventing respiratory droplets containing pathogens from penetrating the fabric material. Although the fabric material can be designed to be disposable, in one embodiment, the fabric material and protective garment made from the fabric material are reusable and can undergo multiple laundry cycles and still retain the desired barrier properties.
When used in the healthcare industry, the protective garment of the present disclosure can be rated according to the Association for the Advancement of Medical Instrumentation (AAMI).
The AAMI uses two tests developed by the American Association of Textile Colorists and Chemists (“AATCC”). AATCC 42 measures a material's water resistance by impact penetration. The material to be tested is held at a 45-degree angle while a fixed amount of water is sprayed on it. A blotter affixed under the material is weighed before and after the water is sprayed to determine how much water penetrated the fabric. According to the present AAMI standard, the material is classified as Level 1 if the weight gain of the blotter is no more than 4.5 grams.
For present AAMI Level 2, the material to be tested must satisfy two AATCC tests—AATCC 42 and AATCC 127. The first test, AATCC 42, is the same as that used for Level 1 except that the increase in the blotter's weight must be no more than 1 gram. The additional test is AATCC 127 which measures a material's resistance to water penetration under hydrostatic pressure. Under this test, a sample of the material to be tested is clamped in place horizontally on the bottom of a glass, metered cylinder. Hydrostatic pressure is increased steadily by increasing the amount of water in the cylinder. To be acceptable for use as a present AAMI Level 2 barrier, the material must be able to resist the penetration of water when it reaches a level of 20 cm.
For present AAMI Level 3, both of the AATCC test methods described above must be satisfied, similar to the requirements to meet the present AAMI Level 2. For AATCC 42, the maximum blotter weight gain is the same as that for Level 2 (i.e., 1 gram). For AATCC 127 to be acceptable for use as a present AAMI Level 3 barrier, the level of water in the cylinder used in AATCC 127 must be at least 50 cm.
For present AAMI Level 4, the AAMI uses two tests developed by the American Society for Testing Materials (“ASTM”)-F1670/F1670M-17a for liquid penetration (i.e., surrogate blood) and F1671/F1671M-13 for viral penetration (i.e., bacteriophage Phi-X174). For surgical gowns and other protective apparel, the material must meet the viral challenge of F1671/F1671M-13 which measures the resistance of materials to bloodborne pathogens using viral penetration at 2 psi and ambient pressure. For surgical drapes and accessories, the material must meet the liquid challenge of F1670/F1670M-17a which measures the resistance of drape materials to penetration by synthetic blood at 2 psi and ambient pressure. For both tests, the results are expressed as pass or fail rather than in terms of a material's resistance.
For ASTM F1671/F1671M-13, the material must pass the test for resistance to penetration by bacteriophage Phi-X174. A sample of the material to be tested is placed vertically in a test cell as a membrane between the media challenge (i.e., liquid) and a viewing chamber. Materials that permit penetration during an hour of a prescribed series of changes in air pressure are not considered suitable for use. For ASTM F1670/F1670M-17a, the material must pass the test for resistance to penetration by synthetic blood. As in the test for viral penetration, the material to be tested is mounted in a vertical position on a cell that separates the surrogate blood liquid challenge and the viewing chamber. The test is terminated if visible liquid penetration occurs at any time before or during 60 minutes of changes in pressure and atmospheric protocols.
Protective garments made in accordance with the present disclosure can pass the AAMI Level 1, the AAMI Level 2, the AAMI Level 3 and/or the AAMI Level 4 requirements as described above. In particular, the protective garment (including all seams) can display an impact penetration according to Test AATCC 42 of one gram or less and can display a hydrostatic pressure according to Test AATCC 127 of 50 cm or greater. In addition, the protective garment can also pass European standards, such as test EN13795 and EN14126. In one aspect, the protective garment or fabric material can display a hydrostatic pressure greater than 60 cm, such as greater than 80 cm, such as greater than 90 cm, even after being laundered 10, 25, 50, 75 or 100 laundry cycles.
When designed to pass the AAMI Level 4 requirements, the fabric material can be a laminate. For example, laminates comprising (i) a woven or non-woven fabric and (ii) an extruded film can be used. In one aspect, the laminate can include a film layer positioned between two outer fabric layers. The film layer can be a microporous poly-tetrafluoroethylene (PTFE) film layer or made from polyester elastomers which are all block copolymers containing 60-70% of a hard (crystalline) segment of polybutylene terephthalate and the balance a soft (amorphous) segment based on long chain polyether glycols. While the soft segments are preferably based on long chain polyethylene glycols, comparable long chain polyether glycols, such as long chain polypropylene glycols, also are suitable. The one or more outer fabric layers can be nonwoven, woven or knitted fabrics. The woven or non-woven fabric used in the laminate can be any fabric which is suitable for use in protective garments for the outdoors (e.g. rainwear, skiwear) or a medical setting. Examples of suitable fabrics are polyester, nylon, polypropylene, Dupont Sontara®, tricot knit cloth nylon or brushed polyester. In another aspect, the fabric can be a meta-aramid non-woven spunlace fabric laminated with an elastomeric coating as described above. The fabric may be used as a moisture barrier for protective garments.
As described above, protective garments of the present disclosure can be designed to be reusable. For example, protective garments made according to the present disclosure can maintain a desired AAMI Level rating even after 60 laundry cycles, such as greater than 75 laundry cycles, such as greater than 85 laundry cycles, such as greater than 100 laundry cycles, such as even greater than 105 laundry cycles. As used herein, a laundry cycle with respect to an AAMI Level rating is according to “Care Code ST.” A laundry cycle not only includes laundering of the protective garment but also a sterilization protocol. One laundry cycle in conjunction with a sterilization protocol is as follows:
Fabric materials treated in accordance with the present disclosure can have a spray rating of at least 70 or higher, such as at least 80 or higher, such as at least 90 or higher even after ten laundry cycles. In one embodiment, for instance, the fabric can maintain a 100 spray rating after ten laundry cycles.
Similarly, the fabric material can also display excellent resistance to water absorption. For example, when tested according to the water absorption test (NFPA 1971 8.25), the fabric can have a water absorption of about 15% or less, such as about 10% or less, such as about 5% or less, such as about 4% or less, such as about 3% or less, such as about 2% or less, such as about 1% or less.
The above water absorption properties can be retained by the fabric after 5 laundry cycles or even after ten laundry cycles.
In addition to water, fabric materials treated in accordance with the present disclosure also provide protection against various chemical agents such as acids, alkaline materials, and artificial blood when tested according to test EN ISO 6530. For example, when tested against a 30% sulfuric acid solution, fabric materials made according to the present disclosure can have an index of repellency of greater than about 85%, such as greater than about 90%, such as greater than about 92%, such as greater than about 94%. The fabric material can have an index of penetration when tested against a 30% sulfuric acid solution of less than about 5%, such as less than about 2%, such as less than about 1%, such as less than about 0.5%. When the fabric material is incorporated into a composite, such as a three layer composite, the index of penetration can be 0%.
When tested against a 10% sodium hydroxide solution, fabric materials made according to the present disclosure can display an index of repellency of greater than about 90%, such as greater than about 92%, such as greater than about 94%, such as greater than about 96%, such as greater than about 97%. The fabric materials can display an index of penetration of less than about 2%, such as less than about 1.5%, such as less than about 1%, such as less than about 0.8%.
Fabric materials made according to the present disclosure also display excellent resistance to artificial blood. When tested against artificial blood, for instance, fabric materials made according to the present disclosure can display an index of repellency of greater than about 85%, such as greater than about 87%, such as greater than about 90%, such as greater than about 92%, such as greater than about 94%. The fabric materials can display an index of penetration against artificial blood of less than about 4%, such as less than about 1.5%, such as less than about 1%, such as less than about 0.8%.
In addition to water repellency, fabric materials made according to the present disclosure also display excellent oil and fuel resistance, especially due to the elastomeric coating. For instance, fabrics made according to the present disclosure can pass ISO Test 6530 directed to the protection against liquid chemicals when tested against, for instance, O-xylene.
Regarding the antimicrobial properties of fabric materials optionally treated with an antiviral agent in accordance with the present disclosure, the fabric materials can be designed to pass ISO Test 18184.
Fabrics made according to the present disclosure can also have excellent air permeability properties, especially compared to fabrics coated with a PTFE membrane. For example, fabrics made according to the present disclosure can have an air permeability of greater than about 0.2 cfm, such as greater than about 0.3 cfm, such as greater than about 0.4 cfm, such as greater than about 0.5 cfm, such as greater than about 0.6 cfm, such as greater than about 0.7 cfm, such as greater than about 0.8 cfm, such as greater than about 0.9 cfm, such as greater than about 1 cfm, such as greater than about 1.2 cfm, such as greater than about 1.4 cfm, such as greater than about 1.6 cfm, such as greater than about 1.8 cfm, such as greater than about 2 cfm, such as greater than about 2.2 cfm, such as greater than about 2.4 cfm, such as greater than about 2.6 cfm, and generally less than about 10 cfm, such as less than about 8 cfm, such as less than about 6 cfm, such as less than about 4 cfm. The above permeability characteristics can be obtained for lightweight fabrics having a basis weight of from about 2 osy to about 5 osy and for heavier basis weight fabrics having a basis weight of from about 5 osy to about 9 osy.
Referring to
Referring to
The fabric material treated in accordance with the present disclosure can be a single layer fabric or a multilayer fabric. The fibers used to make the fabric can depend upon the particular end use application. The fabric material can also contain a woven fabric, a nonwoven fabric, a knitted fabric, a film, and combinations thereof.
For exemplary purposes only, one embodiment of a protective garment for the medical industry is illustrated in
The fabric that is used to construct the garment illustrated in
In one aspect, the protective garment 20 is formed from a polyester woven fabric. For instance, the fabric can contain greater than 80%, such as greater than 90%, such as 100% by weight polyester fibers. The fabric can be formed from polyester yarns. In one aspect, the polyester yarns are formed from continuous filaments, such as polyester multifilament yarns. The yarns in both the warp direction and the fill direction can generally have a relatively low denier. For instance, the yarns can have a denier of less than about 300, such as less than about 200, such as less than about 150, such as even less than about 100. The denier of the yarns is greater than about 10, such as greater than about 50. Each yarn can contain at least about 10 filaments, such as at least about 20 filaments, such as at least about 30 filaments, such as at least about 40 filaments, and generally less than about 100 filaments, such as less than about 70 filaments, such as less than about 60 filaments. In one aspect, the yarn has a denier of from 70 to 75 and contains 30 to 50 filaments per yarn.
In addition to polyester yarns, in one embodiment the fabric can contain anti-static fibers and yarns. For example, anti-static yarns can comprise bicomponent filaments that include a polymer core surrounded by a carbon sheath.
Each yarn can include a single end or can include two ends. Optionally, the yarns can be textured. In such yarns, the filaments are distorted from their generally rectilinear condition to increase the bulk of the yarn and also to provide an ability for a fabric woven therefrom to stretch. A textured yarn may be “set” by heat relaxation to minimize its stretch characteristic, while maintaining its increased bulk, i.e., higher bulked denier.
There are several types of textured yarns capable of being produced by various methods. Different types of textured yarns have different characteristics, some being more expensive than others. The textured yarns that may be employed in the present fabric constructions, or referenced herein, are:
(1) False twist yarn is twisted in one direction, set, then twisted in the opposite direction and set. The twisting, setting, opposite twisting are repeated throughout the length of the yarn.
(2) Core and effect yarn (also known as “core bulked” yarns) is a multiple ended yarn, usually comprising two ends in which one end is essentially straight. The filaments of other end are distorted around the core end and sometimes through the core end.
(3) Air texturized core and effect yarn—is a core and effect yarn in which distortion of the filaments is done by air jet means. An air texturized core and effect yarn has unique properties which distinguish it from other textured yarns. These unique properties have been found effective in attaining the ends herein sought.
In addition to using relatively low denier yarns, the fabric material of the present disclosure can also have a relatively high yarn density. For instance, in the warp direction, the fabric can have greater than about 80 yarns per inch, such as greater than about 100 yarns per inch, such as greater than about 110 yarns per inch, such as greater than about 120 yarns per inch, such as greater than about 130 yarns per inch, such as greater than about 140 yarns per inch, such as greater than about 150 yarns per inch, and generally less than about 200 yarns per inch, such as less than about 180 yarns per inch. In the fill direction, the yarn density can be greater than about 60 yarns per inch, such as greater than about 65 yarns per inch, such as greater than about 70 yarns per inch, such as greater than about 75 yarns per inch, such as greater than about 80 yarns per inch, such as greater than about 85 yarns per inch, and generally less than about 120 yarns per inch, such as less than about 100 yarns per inch, such as less than about 95 yarns per inch.
The fabric material of the present disclosure can also be calendered. Calendering can increase the barrier properties and reduce the permeability of the fabric. During calendering, the fabric is passed between a pair of pressure rolls wherein at least one of the rolls is heated. When a woven polyester fabric is calendered, the fabric is compressed and its density is increased as the interstices between the yarns and the filaments of the yarns are decreased.
The above fabric material represents just one type of fabric that can be treated in accordance with the present disclosure to produce the protective garment as shown in
Protective garments for use in medical industry generally have a light basis weight. For example, the basis weight can be from about 0.5 osy to about 4 osy.
In another aspect, the protective garment of the present disclosure can be designed to be worn by those in the fire service industry. For example, the fabric material can contain flame resistant fibers, such as inherently flame resistant fibers or fibers treated with a flame retardant.
For example, the fabric may be used to construct a garment worn by firefighters. For instance, referring to
In the illustrated embodiment, liner assembly 14 is constructed as a separate unit that may be removed from outer shell 12. A zipper 16 is provided for removably securing liner assembly 14 to outer shell 12. It should be appreciated, however, that other suitable means of attachment, including a more permanent type of attachment such as stitches, may also be used between liner assembly 14 and outer shell 12.
The construction of protective garment 10 is more particularly illustrated in
Thermal barrier layer 54 can be made from various materials. For instance, an aramid felt, such as a felt produced from NOMEX meta-aramid fibers obtained from DuPont can be used. The felt functions as an insulator to inhibit transfer of heat from the ambient-environment to the wearer.
Moisture barrier 56 can be a suitable polymeric membrane that is impermeable to liquid water but is permeable to water vapor or can be an elastomeric coating as described above.
In the embodiment described above, the fireman turnout coat 10 includes multiple layers. In other embodiments, however, it should be understood that a coat or jacket made in accordance with the present disclosure may include a single layer or may include an outer shell attached to a liner. For example, wildland firefighter garments are typically one or two layers.
Referring to
Any of the fabric layers illustrated in the figures can be treated in accordance with the present disclosure. For instance, the outer shell 12, the lining layer 50, the lining layer 52, and/or the thermal barrier layer 54 as shown in
The inherently flame resistant fibers can include, for instance, aramid fibers such as para-aramid fibers and/or meta-aramid fibers. Other inherently flame resistant fibers include polybenzimidazole (FBI) fibers or poly(p-phenylene-2,6-bezobisoxazole) (PBO fibers) and the like. In one embodiment, for instance, the fabric material only contains aramid fibers such as para-aramid fibers alone or in combination with meta-aramid fibers. In still another embodiment, the fabric material contains only meta-aramid fibers. In still another embodiment, the fabric material contains aramid fibers in combination with PBI fibers. The PBI fibers can be present in the fabric material, for instance, in an amount greater than about 20% by weight, such as in an amount greater than about 25% by weight, such as in an amount greater than about 30% by weight, such as in an amount greater than about 35% by weight, such as in an amount greater than about 40% by weight, such as in an amount greater than about 45% by weight, such as in an amount greater than about 50% by weight, and generally in an amount less than about 70% by weight, such as in an amount less than about 60% by weight.
In addition to any of the inherently flame resistant fibers described above, the fabric material may contain other fibers. For instance, the fabric material may also include fibers treated with a flame retardant such as FR cellulose fibers including FR viscose fibers and FR rayon fibers. In addition, the fabric material may include antistatic fibers, nylon fibers, and the like. For example, a fabric materials treated in accordance with the present disclosure can contain nylon fibers in an amount up to about 20% by weight. For instance, nylon fibers can be present in an amount of from about 18% to about 2% by weight, such as from about 15% to about 8% by weight.
The yarns used to produce the fabric material can vary depending upon the particular application and the desired result. In one embodiment, for instance, the fabric material may contain only spun yarns, may contain only filament yarns, or may contain both spun yarns and filament yarns. The number ratio between spun yarns and filament yarns, for instance, can be from about 1:1 to about 10:1. For example, in one embodiment, the fabric material may contain spun yarns to filament yarns in a number ratio of from about 2:1 to about 4:1. When the fabric material is a woven fabric, the fabric can have any suitable weave such as a plain weave, a twill weave, a rip stop weave, or the like.
In one embodiment, the filament yarns may be made from an inherently flame resistant material. For example, the filament yarns may be made from an aramid filament, such as a para-aramid or a meta-aramid filament.
In other embodiments, the filament yarns may be made from other flame resistant materials. For instance, the filament yarns may be made from poly-p-phenylenebenzobisoxazole fibers (PBO fibers), and/or FR cellulose fibers, such as FR viscose filament fibers.
The filament yarns can be combined with spun yarns. Alternatively, the fabric material can be made using only filament yarns or only spun yarns. In accordance with the present disclosure, the spun yarns, in one embodiment, may contain polybenzimidazole fibers alone or in combination with other fibers. For example, in one embodiment, the spun yarns may contain polybenzimidazole fibers in combination with aramid fibers, such as para-aramid fibers, meta-aramid fibers, or mixtures thereof.
Instead of or in addition to containing polybenzimidazole fibers, the spun yarns may contain aramid fibers as described above, modacrylic fibers, preoxidized carbon fibers, melamine fibers, polyamide imide fibers, polyimide fibers, and mixtures thereof.
In one particular embodiment, the spun yarns contain polybenzimidazole fibers in an amount greater than about 30% by weight, such as in an amount greater than about 40% by weight. The polybenzimidazole fibers may be present in the spun yarns in an amount less than about 60% by weight, such as in an amount less than about 55% by weight. The remainder of the fibers, on the other hand, may comprise para-aramid fibers.
In one embodiment, various other fibers may be present in the spun yarns. When the fabric is used to produce turnout coats for firemen, the spun yarns can be made exclusively from inherently flame resistant fibers. When the fabric is being used in other applications, however, various other fibers may be present in the spun yarns. For instance, the spun yarns may contain fibers treated with a fire retardant, such as FR cellulose fibers. Such fibers can include FR cotton, FR rayon, FR acetate, FR triacetate, and FR lyocell, and the like. The spun yarns may also contain nylon fibers if desired, such as antistatic fibers.
The basis weight of the fabric material can vary depending upon the particular type of protective garment being produced. The weight of the outer shell material, for instance, is generally greater than about 4 ounces per square yard, such as greater than about 5 ounces per square yard, such as greater than about 5.5 ounces per square yard, such as greater than about 6 ounces per square yard and generally less than about 8.5 ounces per square yard, such as less than about 8 ounces per square yard, such as less than about 7.5 ounces per square yard.
In another aspect, the fabric material treated in accordance with the present disclosure is a liner fabric. The liner fabric, for instance, can be positioned adjacent to the wearer's body during use. The lining fabric can be made from a combination of spun yarns and filament yarns as described above. The filament yarns can have a size of greater than about 100 denier, such as greater than about 200 denier, and less than about 500 denier, such as less than about 400 denier. In order to increase the lubricity of the liner fabric, the spun yarns and filament yarns can be woven together such that the filament yarns comprise more than about 50% of the surface area of one side of the fabric. For instance, the filament yarns may comprise greater than about 60%, such as greater than about 70%, such as greater than about 80% of one side of the fabric. The side of the fabric with more exposed filament yarns is then used as the interior face of the garment. The filament yarns provide a fabric with high lubricity characteristics that facilitates donning of the garment. For example, the lining fabric can be woven together using a twill weave, such as a 2×1 or 3×1 weave. The lining fabric can have a basis weight of less than about 5 ounces per square yard, such as less than about 4 ounces per square yard, and generally greater than about 2.5 ounces per square yard, such as greater than about 3 ounces per square yard.
In another aspect, the fabric material treated in accordance with the present disclosure is the barrier layer 54 as shown in
The present disclosure may be better understood with reference to the following examples.
Fabric samples were treated with an elastomeric coating in accordance with the present disclosure and tested for water resistance.
The fabric tested was a lightweight (2.5 Oz/SqYd-4.38 Oz/LinYd) 100% Polyester fabric with a plain weave.
Spray Test (AATCC 22) and ISO Test 811 were used to measure the fabric samples. The samples were tested after 10, 25, 50, 75 and 100 laundry cycles. The following results were obtained after the fabric was coated with 90 gsm silicone coating:
The following example demonstrates further benefits and advantages of fabrics made in accordance with the present disclosure.
In this example, various fabrics containing inherently flame resistant fibers were coated with different amounts of silicone. The fabrics were tested for air permeability and liquid penetration when contacted with O-xylene, which is a combustible liquid according to ISO Test T6530 (Protection Against Liquid Chemicals-2005).
The silicone coating applied to the fabric was a two-part mixture containing a silicone oil and a catalyst. The silicone was a siloxane (e.g. polydimethylsiloxane). The mixture had a liquid viscosity at room temperature. For instance, the viscosity of the mixture was less than about 20,000 mPa at 23° C., such as less than about 10,000 mPa, such as less than about 5,000 mPa, and greater than about 500 mPa. The silicone mixture was knife coated onto the fabric.
The following fabrics were tested and the following results were obtained:
A fabric having a basis weight of 6.5 osy and containing 65% by weight para-aramid fibers and 35% by weight meta-aramid fibers did not pass ISO Test 6530 but had a silicone coating add-on of less than 29%. Similarly, a 7 osy fabric containing 60% by weight para-aramid fibers and 40% by weight PBI fibers also did not pass the above test at a silicone coating weight of only 14%. Thus, for higher basis weight fabrics, silicone coating add-on can be greater than about 30% by weight, such as greater than about 35% by weight, such as greater than about 40% by weight, and less than about 300% by weight, such as less than about 250% by weight, such as less than about 225% by weight.
Similar lightweight fabrics having a basis weight of from about 2.7 osy to about 2.9 osy were also laminated with an ePTFE/PTFE membrane and were found to have an air permeability of only about 0.13 cfm. Thus, the silicone coating of the present disclosure not only is fluorine-free and provides protection against liquid chemicals, but also can have an air permeability of greater than about 0.15 cfm, such as greater than about 0.2 cfm, such as greater than about 0.25 cfm, such as greater than about 0.3 cfm, such as greater than about 0.35 cfm, such as greater than about 0.4 cfm, such as greater than about 0.45 cfm, such as greater than about 0.5 cfm, such as greater than about 0.55 cfm, such as greater than about 0.6 cfm, such as greater than about 0.8 cfm, such as greater than about 1 cfm, such as greater than about 1.2 cfm, such as greater than about 1.4 cfm, such as greater than about 1.6 cfm, such as greater than about 1.8 cfm, such as greater than about 2 cfm, such as greater than about 2.2 cfm, such as greater than about 2.4 cfm, such as greater than about 2.6 cfm. For instance, a fabric having a basis weight of from about 2 osy to about 4 osy can have an air permeability of greater than about 0.3 cfm to about 3 cfm, including all increments of 0.1 cfm therebetween. Similarly, a fabric having a higher basis weight of from about 5.5 osy to about 8 osy can have an air permeability of from about 0.3 cfm to about 2.5 cfm, such as from about 0.35 cfm to about 2 cfm.
These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention so further described in such appended claims.
The present application is based upon and claims priority to U.S. Provisional Patent Application Ser. No. 63/315,728, filed on Mar. 2, 2022, and which is incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63315728 | Mar 2022 | US |
