DESC:FIELD OF INVENTION
This disclosure is related to protective apparel which is breathable and liquid proof.
BACKGROUND OF THE INVENTION
Protective work wear for workers doing electrical work is typically made from flame retardant fabric which confers some protection against electrical arcs. Although flame retardant fabrics work well in indoors, such as inside a factory where there is no exposure to rain or other inclement weather, they are not water proof, which reduces their usefulness for workers working outdoors in rain or inclement weather.
At present, polyvinyl chloride (PVC) coated heavy weight flame retardant fabric is layered on either treated flame retardant cotton, or on inherent flame retardant fiber blends. However, PVC layered gear is unpleasant to wear in warm conditions because it is not breathable or light weight, leading to discomfort for the worker doing electrical work.
There are also other safety requirements like high visibility, wind protection, and anti-static properties which are generally not included in currently available PVC coated protective fabrics.
Water proof fabrics comprising ePTFE (expanded polytetrafluoroethylene) lamination are breathable because of their micro porosity. However, the water proofing decreases after laundry washes due to surfactant / detergent particles lodging in the micro pores of the fabric, which reduces water proofing.
There is a need for fabrics which can confer better protection compared to the currently available fabrics for protective wear and also offer ease and flexibility in terms of weight, breathability, liquid resistance, color options, ease of wash/care and usefulness under varying weather conditions.

SUMMARY OF THE INVENTION
Provided herein are garment/yarns/fabrics that have high visibility, breathability, water resistance, wind resistance, chemical resistance, are antistatic, and also confer protection against electric arcs or flash fires. The garment/yarns/fabrics described herein are suitable for manufacture of light weight protective wear which can be used in a variety of weather conditions.
In one aspect, provided herein is a laminated fabric, or garments thereof, comprising
(i) an outer hydrophobic layer,
(ii) a middle layer comprising an expanded polytetrafluoroethylene (ePTFE) membrane coated with polyurethane; and
(iii) an inner hydrophilic layer.
In some embodiments of the laminated fabric, or garments thereof, the ePTFE membrane coated with polyurethane in the middle layer comprises a first ePTFE surface in contact with the outer hydrophobic layer, and a second polyurethane surface in contact with the inner hydrophilic layer.
In some embodiments of the laminated fabric, or garments thereof, the outer hydrophobic layer comprises a fabric woven from yarns comprising cellulosic fibers, man-made fibers, flame retardant polymers, or a combination thereof.
In some embodiments of the laminated fabric, or garments thereof, the flame retardant polymers in the outer hydrophobic layer comprise modacrylic fibers, aramid fibers, carbon fibers, vinyl fibers, viscose fibers, polyacryl nitrile fibers, polybenzimidazole fibers, or a blend thereof.
In some embodiments of the laminated fabric, or garments thereof, the cellulosic fiber in the outer hydrophobic layer is cotton, viscose rayon, or a blend of cotton or viscose rayon with polyester or nylon where the polyester or nylon is up to 50% of the total weight of the fiber.
In some embodiments of the laminated fabric, or garments thereof, the cellulosic fiber in the outer hydrophobic layer is treated with tetrakis (hydroxymethyl) phosphonium chloride or tetrakis (hydroxymethyl) phosphonium sulfate.
In some embodiments of the laminated fabric, or garments thereof, the flame retardant polymer in the outer hydrophobic layer comprises modacrylic in an amount of 40% to 60% by weight of the fabric, and aramid and in an amount of 5% to 10% by weight of the fabric.
In some embodiments of the laminated fabric, or garments thereof, the cellulosic fiber in the outer hydrophobic layer is present in an amount of 30% to 50% by weight of the fabric.
In some embodiments of the laminated fabric, or garments thereof, the flame retardant polymer in the outer hydrophobic layer comprises aramid in an amount of 30% to 40% by weight of the fabric, and flame retardant viscose and in an amount of 40% to 60% by weight of the fabric.
In some embodiments of the laminated fabric, or garments thereof, the man-made fiber in the outer hydrophobic layer is nylon.
In some embodiments of the laminated fabric, or garments thereof, the outer hydrophilic layer comprises from about 5% to about 10% nylon.
In some embodiments of the laminated fabric, or garments thereof, described herein, the outer hydrophobic layer is treated with a fluorocarbon.
In some embodiments of the laminated fabric, or garments thereof, described herein, the outer hydrophobic layer further comprises anti-static fibers.
In some embodiments of the laminated fabric, or garments thereof, the inner hydrophilic layer comprises a flame retardant lining fabric meeting the requirements of ISO 15025 is
In some embodiments of the laminated fabric, or garments thereof, the inner hydrophilic layer comprising a flame retardant lining fabric meeting the requirements of ISO 15025 comprises a blend of about 60% modacrylic and about 40 % cellulosic fiber by weight of the fabric.
In some embodiments of the laminated fabric, or garments thereof, the inner hydrophilic layer is further treated with a wicking finish agent, an antimicrobial agent, or a combination thereof.
In another aspect, provided herein is a process for manufacturing the laminated fabrics described herein, comprising
(i) maintaining the adhesive viscosity at the melter in a range of from about 5500 millipascal seconds (mPa.s) to about 3800 mPa.s at a temperature ranging from about 100 oC to about 110 oC;
(ii) transferring the melt to a knife where the viscose melt is maintained at a viscosity ranging from about 7050 mPa.s to about 5500 mPa.s at a temperature of about 90 oC to about 100 oC;
(iii) coating the ePTFE side of the membrane in the middle layer with the viscose melt and laminating the outer hydrophobic layer to the membrane in the middle layer on the ePTFE side;
(iv) coating the polyurethane side of the membrane in the middle layer with a hot melt polyurethane adhesive thereby laminating the inner hydrophilic layer to the membrane in the middle layer on the polyurethane side; and
(v) curing the laminated fabric of step (iv) at room temperature with steam in a tight and non-stretched condition for 24 hours.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
Figure 1: shows a three layer fabric
Figure 2: shows hot melt lamination.
Figure 3: shows further details of hot melt lamination.
DETAILED DESCRIPTION OF THE INVENTION
All materials used herein were commercially purchased as described herein or prepared from commercially purchased materials as described herein.
Described herein are garments/fabrics that have high visibility, breathability, water resistance, wind resistance, chemical resistance, are antistatic, and also confer protection against electric arcs or flash fires. The garment/fabrics described herein are suitable for manufacture of light weight protective wear which can be used in a variety of weather conditions.
The garments/fabrics described herein do not allow liquid (e.g., rainwater) to penetrate but are permeable and allow water vapor (e.g., sweat) to evaporate. Further the micro-porous garments/fabrics described herein are breathable, thus rendering them comfortable to wear under a variety of weather conditions.
In one aspect, provided herein are laminated fabrics, or garments thereof, comprising: (i) an outer hydrophobic layer, (ii) an expanded polytetrafluoroethylene (ePTFE) membrane coated with polyurethane; and (iii) an inner hydrophilic layer.
In some embodiments, the ePTFE membrane coated with polyurethane comprises a first ePTFE surface in contact with the outer hydrophobic layer, and a second polyurethane surface in contact with the inner hydrophilic layer.
In some embodiments, the outer hydrophobic layer comprises a fabric coated with a flame retardant. In other embodiments, the outer hydrophobic layer comprises a fabric woven from yarns comprising cellulosic fibers or man-made fibers and flame retardant polymers. In some embodiments, the inner hydrophilic layer comprises a flame retardant lining fabric meeting ISO 15025 standards. In some embodiments, a flame retardant lining fabric comprises modacrylic or modacrylic blends comprising cotton or rayon. In some embodiments, the outer hydrophobic layer is water repellant. In some embodiments, the inner lining fabric is further coated with an antimicrobial agent thereby rendering the fabric/garment odor resistant (e.g., body odor resistant).
As used herein, modacrylic fibers are manufactured fibers in which the fiber-forming substance is any long-chain synthetic polymer composed of less than 85%, but at least 35% weight acrylonitrile units. A modacrylic has properties that are similar to an acrylic, but a modacrylic is flame retardant and does not combust. Modacrylic fibers/fabrics are difficult to ignite and will self-extinguish.
In some embodiments, the laminated fabrics, or garments thereof, described herein are three layer fabrics, or garments thereof, wherein the outer or first layer comprises a flame retardant meeting the requirements of NFPA 2112, ISO 15025, ASTM F1959/F1959M – 13, and EN 61482-1-1, highly visible colors meeting the requirement of ISO 20471/ANSI/ISEA 107-1999, having antistatic properties meeting the requirements of EN 1149/5, and conferring protection against liquids, meeting the requirements of EN ISO 13034.
The NFPA 2112 standard provides minimum requirements for the design, construction, evaluation, and certification of flame-resistant garments for use by industrial personnel, with the intent of not contributing to the burn injury of the wearer, providing a degree of protection to the wearer, and reducing the severity of burn injuries resulting from short-duration thermal exposures or accidental exposure to flash fires. The NFPA 2112 standard shall specify the minimum performance requirements and test methods for flame-resistant fabrics and components and the design and certification requirements for garments for use in areas at risk from flash fires.
ISO 15025: is a method for testing for limited flame spread and specifies two procedures (surface ignition and bottom-edge ignition) for determining flame spread properties of vertically oriented flexible materials in the form of single or multi-component fabrics (coated, quilted, multi-layered, sandwich constructions and similar combinations), when subjected to a small defined flame. This test standard does not apply to situations where there is restricted air supply or exposure to large sources of intense heat, for which other test methods are more appropriate. This test method is not appropriate for materials that demonstrate extensive melting or shrinkage.
ASTM F1959 / F1959M are standard test methods for determining the Arc Rating of materials for clothing.
EN 61482-1-2 standard rates protective clothing against the hazards of an electric arc. Under this standard the protection property of the fabric or the garment against the thermal effects of an electric arc event is defined as its Arc Thermal Protection Value (ATPV) expressed in cal/cm².
EN ISO 20471 specifies requirements for high visibility clothing which is capable of visually signalling the user's presence. The high visibility clothing is intended to provide conspicuity of the wearer in any light condition when viewed by operators of vehicles or other mechanized equipment during daylight conditions and under illumination of headlights in the dark. Performance requirements are included for color and retroreflection as well as for the minimum areas and for the placement of the materials in protective clothing.
ANSI/ISEA 107-2015 American National Standard for High-Visibility Safety Apparel and Accessories, ANSI/ISEA 107-2010 and ANSI/ISEA 207, American National Standard for High-Visibility Public Safety Vests, is an effort to establish a single, comprehensive document that considers all occupational tasks. The standard continues to present three performance classes of garments based on the amount of visible materials and design attributes incorporated into the final configuration, and identifies garment types based on expected use settings and work activities being performed. These are designated as off-road (type O), roadway and temporary traffic control (type R), or public safety activities (type P)
EN 1149-5 is a European standard for protective clothing with antistatic characteristics. The clothing protects against sudden discharges of electrostatic energy and should be worn whenever there is a risk that static sparks may ignite inflammable substances such as gas and oil.
EN ISO 13034 Protection against liquid chemical products. The fabric is tested in various ways to determine its tensile strength and resistance to chemicals. In these tests, 4 solutions of chemicals (H2SO4, NaOH, n-heptane and isopropanol) are applied to a fabric sample. The quantities of liquid that drip off and that penetrate the fabric are determined and must be within the tolerances set in the standard.
The second or middle layer comprises a membrane of ePTFE (expanded polytetrafluoroethylene) membrane layer, coated with PU (polyurethane), in which the polyurethane side/face/surface is hydrophilic and the ePTFE side/face/surface is hydrophobic. Said membrane is a breathable membrane with flame retardant properties due to the presence of the polyurethane coat. The ePTFE side/face/surface contacts the outer layer and the polyurethane side/face/surface contacts the third or inner layer. The third/inner layer comprises a flame retardant lining fabric meeting the requirements of ISO 15025.
In some embodiments, the laminated and/or three layer fabrics, or garments thereof, are prepared/manufactured by hot melt lamination as described in the Figures and in the examples section. Two hot melt laminations are employed to provide the three layered fabrics/garments described herein. In a first hot melt lamination, the outer layer and the ePTFE surface of the ePTFE membrane coated with polyurethane are laminated, and then in a second hot melt lamination, the polyurethane surface of the ePTFE membrane coated with polyurethane is laminated to the inner layer.
In certain embodiments, the outer fabric comprises either woven or knitted or other inherent (e.g., flame retardant polymer coated or flame retardant polymer co-spun) flame retardant fibers of 150 to 250 gsm or comprises THPX treated cellulosics of 230 to 300 gsm.
In some embodiments, the outer hydrophobic layer comprises from about 40 % to about 60% by weight of modacrylic by total weight of the fabric; from about 30 % to about 40 % by weight of cellulosic fiber (e.g., cotton or rayon) by total weight of the fabric; from about 5 % to about 10% by weight of para aramid by total weight of the fabric; from about 5 % to about 10% by weight of Nylon 66 by total weight of the fabric; and about 0.4% to about 2 % by weight of an antistatic fibers by total weight of the fabric. In some of such embodiments, the fabric is an inherent woven twill fabric. By way of example, antistatic fibers include and are not limited to NO-SHOCK® anti-static fibers, BELLTRON® anti-static conductive fibers, NEGA-START® antistatic fibers and the like.
In other embodiments, the outer hydrophobic layer comprises from about 40 % to about 60% by weight of flame resistant viscose by total weight of the fabric; from about 30 % to about 40 % by weight of Aramid by total weight of the fabric; from about 5 % to about 10% by weight of Nylon 66 by total weight of the fabric; and from about 0.4% to about 2 % by weight of an antistatic fibers by total weight of the fabric. In some of such embodiments, the fabric is a single jersey fabric.
As used herein “flame retardant viscose” refers to a Rayon fiber wherein flame retardants are incorporated at the time of solution spinning. “Rayon fiber” refers to regenerated cellulose fiber.
In some embodiments, the outer / hydrophobic layer comprises THPX-treated woven or knitted fabric wherein THPX is a treatment which renders cellulosic rich fibers/fabric permanently flame retardant. Said THPX treatment of the cellulosic rich fibers/fabric is conducted with tetrakis (hydroxymethyl) phosphonium chloride or with tetrakis (hydroxymethyl) phosphonium sulfate.
In additional embodiments, the outer hydrophobic layer is finished with a fluorocarbon by employing a pad – dry- cure method, which renders the fabric hydrophobic. Typically, C6 fluorocarbons are employed (e.g., fluorocarbons purchased from Huntsman, Archroma, Britacel or any other suppliers).
In some embodiments, the inner hydrophillic layer or lining layer comprises woven, knitted or single jersey fabric. In some embodiments, the inner hydrophillic layer or lining layer comprises a blended modacrylic. In some of such embodiments, the inner hydrophillic layer or lining layer comprises from about 60% by weight of modacrylic by total weight of the fabric; and about 40% by weight of a cellulosic (e.g., cotton or rayon) by total weight of the fabric. In some embodiments, the inner hydrophillic layer or lining layer further comprises a wicking finish agent and/or an antimicrobial agent. Here In some cases, the lining layer comprises a hydrophilic softener (e.g., polyurethane or silicone based softener) for wicking. In some instances, the lining layer comprises a non-leaching silver based antimicrobial agent. The fabric is treated with a hydrophilic softener+ antimicrobial agent by a pad-dry-cure method.
Also provided herein is a process for manufacture of laminated and/or three layer fabrics described herein comprising, in a first sub-process the lamination of the outer layer with the ePTFE side of the membrane, and in a second sub-process, the lamination of the product of the first sub-process with the inner lining fabric wherein the polyurethane side of the membrane is laminated with the inner lining fabric.
A reactive adhesive (reactive polyurethane-based hot melt adhesives) is used for the hot melt lamination process. Once the reactive adhesive has been applied, it initially sets, followed by a chemical reaction in the presence of ambient humidity resulting in polymers with high cohesion, thereby conferring high adhesion values, high degrees of temperature resistance, flexibility at cold temperatures and solvent/liquid resistance to the fabric.
The adhesive is heated prior to the lamination process and then applied to the layers to be laminated by an engraved roller which allows for even distribution of the glue. The resulting textile product (fabric) does not undergo any thermal changes and the resulting textile product (fabric) also retains its thickness and/or stiffness and shape (i.e., does not undergo shrinking or stretching).
The laminated fabrics, or garments thereof, and the processes of manufacture described herein allow for manufacture of clothing which is breathable and comfortable, wicks away sweat from the inside, provides life time protection against liquids such as rain and/or chemical spills even after multiple washes, confers life time protection against cold wind, flash fires / electric arc hazards, and further, retains color fastness despite multiple wash/laundry cycles. Further, the fabrics/garments described herein are easily washable as they have a water repellant layer on the outside. In additional embodiments, the fabrics/garments described herein comprise lining fabrics coated with antimicrobials, thereby rendering the fabrics/garments odor resistant, and wicking finishes.
“Arc Thermal Protective Value” (ATPV) refers to the maximum incident energy (in calories per centimeter squared) that protective equipment can be exposed to and prevent onset of a second-degree burn. Ratings are based upon the total weight of the fabric.
A Hazard Risk Category (HRC) level is determined by the minimum amount of calories per square centimeter (ATPV or Cal/cm2). Any treated garment must pass through with a 50% probability of a 2nd or 3rd degree burn occurring, which is how the protective level of the treated clothing is determined. The higher the ATPV, the higher the HRC level attained, the greater the protection that is needed. Typical HRCs are given below.
HRC 1: 4 Cal/cm2 = ATPV < 8 Cal/cm2
HRC 2: 8 Cal/cm2 = ATPV < 25 Cal/cm2
HRC 3: 25 Cal/cm2 = ATPV < 40 Cal/cm2
HRC 4: 40 Cal/cm2= ATPV
As shown in the examples section, the fabrics and methods of production of fabrics described herein can provide ATPV of 7.9 cal/cm2 (HRC 1) ar 150 gsm and ATPV 9.5 cal/cm2 (HRC 2) at 180 gsm.
The protective wear described herein complies with standards such as NFPA 2112, ISO 15025, EN 1149/5, ASTM F1959/F1959M – 13, EN 61482-1-1. The NFPA 2112 standard provides minimum requirements for the design, construction, evaluation, and certification of flame-resistant garments/apparel for use by industrial personnel, with the intent of not contributing to the burn injury of the wearer, providing a degree of protection to the wearer, and reducing the severity of burn injuries resulting from short-duration thermal exposures or accidental exposure to flash fires.
The National Fire Protection Association (NFPA) is a United States trade association, albeit with some international members, that creates and maintains private, copyrighted standards and codes for usage and adoption by local governments. This includes publications from model building codes to the many on equipment utilized by firefighters while engaging in hazardous material (hazmat) response, rescue response, and some firefighting. The International Organization for Standardization (ISO) is an international standard-setting body composed of representatives from various national standards organizations. ISO 15025: Protective clothing -- Protection against heat and flame -- Method of test for limited flame spread. EN 1149/5 electrostatic properties. Material performance and design requirements: This standard specifies requirements for materials and design of protective clothing with electrostatic dissipation, used as part of a complete set grounded to avoid incendiary discharges. These requirements may not be sufficient in flammable atmosphere rich in oxygen. This European Standard is not applicable for protection against voltage. Other standards are: ASTM F1959/F1959M – 13: Standard Test Method for Determining the Arc Rating of Materials for Clothing. EN 61482-1-1: Determination of the arc rating (ATPV) of flame resistant materials for clothing.
EXAMPLES
Example 1: Outer layer HRC 2
150 to 250 grams per square meter (gsm) inherent woven twill fabric
Blend 1: 40 to 60% by weight modacrylic.
30 to 40 % Cellulosic fiber like cotton or rayon.
5 to 10% para aramid
5 to 10% Nylon 66
0.4 to 2% antistatic fibers
OR
Blend 2: aramid, 30% to 40 %
Flame retardant viscose, 40 to 60%
Nylon 66, 5% to 10 %
Antistatic fibers 0.4 to 2%
Colour: High visible, and optionally any other colour passing ISO 20471.
ISO 20471 specifies requirements for high visibility clothing which is capable of visually signaling the user's presence. The high visibility clothing is intended to provide conspicuity to the wearer in any light condition when viewed by operators of vehicles or other mechanized equipment during daylight conditions and/or under illumination of headlights in the dark.
Performance requirements are included for color and retro-reflection as well as for the minimum areas and for the placement of the materials in protective clothing.
Finish: Treated with fluorocarbon
Example 2: Outer layer HRC 2
150 to 250 gsm Single Jersey
Blend 1: 40 to 60% by weight Modacrylic.
30 to 40 % Cellulosic like cotton or rayon.
5 to 10% para aramid
5 to 10% Nylon 66
2% antistatic agent.
OR
Blend 2: Aramid, 30% to 40 %
Flame retardant Viscose, 40 to 60%
Nylon 66, 5% to 10 %
Antistatic fibers 0.4 to 2%
Colour: High visible, or any other color passing ISO 20471.
Finish: Treated with fluorocarbon.
Example 3: Outer layer: THPX treated woven/ knitted fabric of 230 to 300 gsm.
THPX is a treatment which make cellulosic rich fabric permanently flame retardant.
It’s basically of two types:
1) Tetrakis (hydroxymethyl) phosphonium chloride
Or
2) Tetrakis (hydroxymethyl) phosphonium sulfate.
And the process is as follows.
Fabric treated with THPX – Ammonia curing – oxidation – washing - treated with fluorocarbon.
Example 4: Lining fabric
The lining fabric is made of either woven or knitted 60 to 100 gsm blended modacrylic, e.g., 80 gsm plain weave fabric.
Blend: 60% modacrylic / 40 % cellulosic like cotton or rayon
Finish: wicking finish and antimicrobial agents
Example 5 Lining fabric
80 gsm single jersey.
Blend: 60% Modacrylic / 40 % Cellulosic like cotton or rayon
Finish: wicking finish.
The lamination process involves a sequence of unloading – adhesive coating – laminating – loading – curing. The adhesive viscosity is maintained from about 5500 to about 3800 mPa.s (millipascal seconds) at the melter by heating the adhesive (e.g., a reactive polyurethane-based hot melt adhesive) at a temperature ranging from about 100 oC to about 110 oC. The melt is transferred to the knife where the viscose is maintained at 7050 to 5500 mPa.s and at a temperature of about 90 oC to about 100 oC.
As described in the Figures, the coating of polyurethane and/or adhesive is done by a Grove roller such that about 30 % to about 40 % of the membrane/fabric area is coated to get the required adhesive force. The outer layer is laminated with the PU-coated ePTFE membrane on the ePTFE side. The inner layer is laminated with the PU-coated ePTFE membrane on the PU side. After lamination of materials the final product is cured at room temperature with steam in a tight/non-stretched condition for 24 hours.
This laminated three-layered fabric showed liquid protection and flame retardant properties as shown by test results below.
1) Rain Test as per AATCC 35 RIGID, 5 MIT 915 MM. Determination was 0.632 gm. Requirement is less than 2 gm
2) Moisture Vapor Transmission as per ASTM E96/E96M/BW - 4700 gm/Mtr2/24 Hr
3) Water Resistance as per AATCC 127, Dynamic test mode pressure gradient 60 mbar/mit, test area 100+/- 5 cmsq is 1000 cm (requirement is 20 cm).
4) Flammability test as per ASTM D6413 is 40 mm (requirement less than 100 mm).
AATCC 35(Rain Test) fabric waterproof performance rain measurement is a standard applied to any anti-impact penetration of the textile fabric with or without water repellent treatment. Test principle: wrap the test sample with a weighed absorbent paper 600 mm thick. Spray water for 2 minutes, and then weigh the weight of absorbent paper again, calculate the amount of water leakage during the test process. It is required that the weight difference before and after the test of the absorbent paper does not exceed 1 gram. The test was conducted with 915 mm paper, and water was sprayed for 5 minutes.
ASTM E96/E96M/BW - Test Method of Water Vapor Transmission: A desiccant, Potassium Acetate, is put into a cup and sealed with a piece of film. The fabric to be tested is then placed over the cup with the fabric side to the cup. The cup is then inverted into a pan of water. Then after a period of time the cup is weighed to see how much water has been “pulled” into the cup through the fabric. The weight is then extrapolated to show the number of grams per 24hours / per sq. meter of fabric that will pass through the fabric.
AATCC 127: Water Resistance: Hydrostatic Pressure Test measures the resistance of a fabric to the penetration of water under hydrostatic pressure. It is applicable to all types of fabrics, including those treated with a water resistant or water repellent finish. Water resistance depends on the repellency of the fibers and yarns, as well as the fabric construction. One surface of the test specimen is subjected to a hydrostatic pressure, increasing at a constant rate, until three points of leakage appear on its other surface.
ASTM D6413: Standard Test Method Flame Resistance of Textiles (Vertical Test) is the defining Test Method for compliance with OSHA 1910.269 and one of the most commonly used tests on flame resistant fabrics. Adopted from Federal Test Standard No. 191A, method 5903.1, the vertical flame test has been used for many years. The purpose of this test is to determine whether a fabric will continue to burn after the source of ignition is removed. A 12” specimen of fabric is suspended in an enclosed chamber (secured on three sides). The cut edge of the fabric on the bottom is exposed to a controlled methane flame for 12 seconds. After exposure to the flame, after flame, afterglow and char length are measured. Five tests are performed, and the results are averaged and reported as the test result. ASTM D6413 is used to determine a pass/fail criterion for ASTM F1506, which requires a maximum char length of 6 inches. ASTM F1506 requires a maximum char length of 6 inches under this test method, whereas NFPA 2112 requires a maximum of 4 inches. A 6-inch char length is more universally accepted as the maximum.
The laminated fabric was used for making garments; flame retardant trims like swing thread, zipper etc. were used for garment manufacturing along with seam seals at stitch/swing areas. Seam seals are required for liquid proofing because liquid can pass through seam areas. Accordingly, all the stitch/seam areas are sealed with seam shell tape which is thermoplastic in nature, followed by heat treatment in a seam seal machine to finish the seam seals.

The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

,CLAIMS:
1. A laminated fabric, or garments thereof, comprising
(i) an outer hydrophobic layer,
(ii) a middle layer comprising an expanded polytetrafluoroethylene (ePTFE) membrane coated with polyurethane; and
(iii) an inner hydrophilic layer.
2. The laminated fabric, or garments thereof, of claim 1, wherein the ePTFE membrane coated with polyurethane in the middle layer comprises a first ePTFE surface in contact with the outer hydrophobic layer, and a second polyurethane surface in contact with the inner hydrophilic layer.
3. The laminated fabric, or garments thereof, of claim 1, wherein the outer hydrophobic layer comprises a fabric woven from yarns comprising cellulosic fibers, man-made fibers, flame retardant polymers, or a combination thereof.
4. The laminated fabric, or garments thereof, of claim 3, wherein the flame retardant polymers in the outer hydrophobic layer comprise modacrylic fibers, aramid fibers, carbon fibers, vinyl fibers, viscose fibers, polyacryl nitrile fibers, polybenzimidazole fibers, or a blend thereof.
5. The laminated fabric, or garments thereof, of claim 3, wherein the cellulosic fiber in the outer hydrophobic layer is cotton, viscose rayon, or a blend of cotton or viscose rayon with polyester or nylon where the polyester or nylon is up to 50% of the total weight of the fiber.
6. The laminated fabric, or garments thereof, of claim 5, wherein the cellulosic fiber in the outer hydrophobic layer is treated with tetrakis (hydroxymethyl) phosphonium chloride or tetrakis (hydroxymethyl) phosphonium sulfate.
7. The laminated fabric, or garments thereof, of claim 3, wherein the flame retardant polymer in the outer hydrophobic layer comprises modacrylic in an amount of 40% to 60% by weight of the fabric, and aramid and in an amount of 5% to 10% by weight of the fabric.
8. The laminated fabric, or garments thereof, of claim 7, wherein the cellulosic fiber in the outer hydrophobic layer is present in an amount of 30% to 50% by weight of the fabric.
9. The laminated fabric, or garments thereof, of claim 3, wherein the flame retardant polymer in the outer hydrophobic layer comprises aramid in an amount of 30% to 40% by weight of the fabric, and flame retardant viscose and in an amount of 40% to 60% by weight of the fabric.
10. The laminated fabric, or garments thereof, of claim 3, wherein the man-made fiber in the outer hydrophobic layer is nylon.
11. The laminated fabric, or garments thereof, of claim 10, wherein the outer hydrophilic layer comprises from about 5% to about 10% nylon.
12. The laminated fabric, or garments thereof, of any one of claims 1-11, wherein the outer hydrophobic layer is treated with a fluorocarbon.
13. The laminated fabric, or garments thereof, of any one of claims 1-11, wherein the outer hydrophobic layer further comprises anti-static fibers.
14. The laminated fabric, or garments thereof, of claim 1, wherein the inner hydrophilic layer comprises a flame retardant lining fabric meeting the requirements of ISO 15025.
15. The laminated fabric, or garments thereof, of claim 14, wherein the inner hydrophilic layer comprising a flame retardant lining fabric meeting the requirements of ISO 15025 comprises a blend of about 60% modacrylic and about 40 % cellulosic fiber by weight of the fabric.
16. The laminated fabric, or garments thereof, of claim 14, wherein the inner hydrophilic layer is further treated with a wicking finish agent, an antimicrobial agent, or a combination thereof.
17. A process for manufacturing the laminated fabric of claim 1, comprising
(i) maintaining the adhesive viscosity at the melter in a range of from about 5500 millipascal seconds (mPa.s) to about 3800 mPa.s at a temperature ranging from about 100 oC to about 110 oC;
(ii) transferring the melt to a knife where the viscose melt is maintained at a viscosity ranging from about 7050 mPa.s to about 5500 mPa.s at a temperature of about 90 oC to about 100 oC;
(iii) coating the ePTFE side of the membrane in the middle layer with the viscose melt and laminating the outer hydrophobic layer to the membrane in the middle layer on the ePTFE side;
(iv) coating the polyurethane side of the membrane in the middle layer with a hot melt polyurethane adhesive thereby laminating the inner hydrophilic layer to the membrane in the middle layer on the polyurethane side; and
(v) curing the laminated fabric of step (iv) at room temperature with steam in a tight and non-stretched condition for 24 hours.