Patent Application
20250188653
The disclosure relates to a multilayer fabric for personal protective equipment to protect a wearer from flame and/or art flash, and personal protective equipment formed by using the same. More specifically, the disclosure relates to a multilayer fabric for personal protective equipment and personal protective equipment formed by using the same, wherein the multilayer fabric is a multilayer fabric used to manufacture personal protective equipment that not only can effectively protect a wearer from flame and/or arc flash which are categorized into hazard/risk category (HRC) level 4, but also can provide excellent lightness, durability, wearer-friendliness, and high activity functions.
Recently, economic growth and abnormal climate changes around the globe have brought with them fires of increasing scale. As a result, damage to human life and property is also on the rise, and accordingly, laws and regulations related to fire prevention and safety accidents are being tightened. To reduce the scale of human injuries and material damage caused by fire, it is necessary to widely apply materials having excellent flame retardancy in the development and manufacture of personal protective equipment.
In this regard, the electricity-related safety issues are continuously emerging due to several large-scale fires in electrical facilities caused by electrical factors, such as arc flash or the like, and resulting human injuries. In particular, the need to effectively protect human life by lowering a fatality rate of workers from electrical arc flash, which accounts for 80% or more of electrical accidents and has a high fatality rate of workers due to accidental exposure, and at the same time, by reducing risks to wearers, is emerging.
Recently, in order to protect workers from electrical arc flash explosion accidents that cannot be protected with existing flame retardant clothing, in Saudi Arabia, electrical construction companies are being required to provide specific alternatives for worker protection, such as adding protection against arc flash to the performance indicators of personal protective equipment worn by field workers. Accordingly, the request of development and demand for personal protective equipment that can effectively protect a wearer from arc flash is rapidly increasing.
Also, other Middle Eastern countries, such as UAE, Qatar, Kuwait, and Oman, also investing heavily in the construction of infrastructure to expand the national power grids. In the United States, the demand for the construction of new and renewable energy plants is increasing due to the establishment of a stable electricity supply network for the expansion of the domestic manufacturing bases and in accordance with the implementation of the global carbon neutrality policy. Accordingly, the market for personal protective equipment (PPE) to protect workers from electrical accidents, especially arc flashes, is growing significantly.
Arc flash is a phenomenon in which high-temperature flames and explosions occur due to the instantaneous release of accumulated electrical energy, and accounts for about 80% of all electricity-related accidents. In the United States, it is known that about 30,000 arc flash accidents occur annually, resulting in about 7,000 burn injuries and 400 deaths.
Arc flash is accompanied by high-temperature flames close to about 20,000° C. and afterstorm. Thus, workers exposed to arc flash may suffer from heat burns and fatal injuries such as blindness and hearing damage due to flying debris. Therefore, arc flash PPE should have comprehensive protective performance to protect workers not only from high heat caused by instantaneous flames but also from high levels of explosion energy.
The protective performance of arc flash PPE is determined according to the arc thermal protective value (ATPV), i.e., absorbable energy per unit area, presented in ‘NFPA 70E’ which is the electrical safety standard of US National Fire Protection Association (NFPA), and the resulting HRC levels. These standards require not only general flame proof performances, but also strict protection performance to respond to instantaneous flames. Therefore, the technical difficulty of developing effective and efficient arc flash PPE is considerably high.
Table 1: Personal protective equipment (PPE) performance criteria for arc flash protection as presented in NFPA 70E of the US NFPA
The HRC is set by a minimum caloric amount, i.e., minimum arc rating (unit: cal/cm2) that represents minimum amount of projected energy per square centimeter that a worker would receive from arc flash. Every garment or set of garments tested should have a 50% chance of causing a 2nd or 3rd degree burn to a wearer. There are five risk levels: 0, 1, 2, 3, and 4. Level 0 is the level of little or no risk, and level 4 is the highest or most dangerous level. Table 1 presents the minimum arc rating requirements for each level. For example, PPE that can respond to HRC level 2 is at a level that a worker can be protected in a simple work environment (low-voltage environment of 600 V or less and small-scale transformer operating conditions). The higher the result expressed in cal/cm2 for a tested fabric, the higher the HCR level achieved. In particular, in order to manufacture work clothes or uniforms that effectively protect operators in environments where they are constantly exposed to high temperatures, such as crude oil production facilities, petroleum product manufacturing plants, steel mills, substations, and power plants, developing fabrics for PPE that are resistant to flame and/or arc flash and have excellent flame propagation blocking properties, lightness, wearer-friendliness, and durability is still an uphill battle due to technical difficulties.
Provided is a multilayer fabric available to manufacture personal protective equipment that meet the requirements of HRC level 4, the multilayer fabric not only being able to effectively protect a wearer from flame and/or arc flash, but also providing excellent durability and lightness and high activity functions.
Provided is personal protective equipment, such as work clothes or uniforms, that meets the requirements of HRC level 4, the personal protective equipment not only being able to effectively protect a wearer from flame and/or arc flash, but also providing excellent durability and lightness and high activity functions.
Additional aspects will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the presented embodiments of the disclosure.
According to an aspect of the disclosure, a multi-layer fabric, which is a multilayer fabric for personal protective equipment to protect a wearer from flame and/or arc flash, includes
In an embodiment, the plurality of embossed dots may each have a quadrangular shape with a length of one side of about 1.0 mm to about 5.0 mm and a height of about 0.5 mm to about 3.0 mm, may have a dot density of about 10,000 dots to about 100,000 dots per square meter of the intermediate layer, and may be spaced apart by intervals of about 2.0 mm to about 6.0 mm.
In an embodiment, the plurality of embossed stripes in the nonwoven fabric layer may each have a width of about 1.0 mm to about 5.0 mm and a height of about 0.5 mm to about 3.0 mm, may be spaced apart by intervals of about 2.0 mm to about 6.0 mm, and may have a stripe density of about 60 stripes to about to 800 stripes per square meter of the intermediate layer.
In an embodiment, the nonwoven fabric layer may be a spunlace nonwoven fabric layer or a needle punched nonwoven fabric layer.
In an embodiment, the nonwoven fabric layer may consist of an aramid fiber in an amount of 70 wt % or more based on the total weight of fibers constituting the nonwoven fabric layer.
In an embodiment, the nonwoven fabric layer may consist of at least one type of aramid fiber selected from a meta-aramid fiber and a para-aramid fiber, in an amount of 90 wt % or more based on the total weight of fibers constituting the nonwoven fabric layer.
In an embodiment, the nonwoven fabric layer may consist of a para-aramid fiber in an amount of 97 wt % or more based on the total weight of fibers constituting the nonwoven fabric layer.
In an embodiment, the outer layer may be a woven fabric layer with a twill weave, and the inner layer may be a woven fabric layer with a plain weave.
In an embodiment, in the first composite spun yarn and the second composite spun yarn of the outer layer and the inner layer, respectively, the aramid fiber, the flame retardant cellulose fiber, and the antistatic fiber may be in the form of staple fiber.
In an embodiment, in the outer layer and the inner layer, a weight ratio of the aramid fiber:flame retardant cellulose fiber:antistatic fibers may be 45 to 70:30 to 70:1 to 5.
In an embodiment, the meta-aramid fiber may preferably be poly(m-phenylene isophthalamide) fiber, and the para-aramid fiber may preferably be poly(p-phenylene terephthalamide) fiber.
In an embodiment, the meta-aramid fiber may be poly(m-phenylene isophthalamide) fiber, and the para-aramid fiber may be poly(p-phenylene terephthalamide) fiber.
In an embodiment, the flame retardant cellulose fiber may be a flame retardant cellulose rayon fiber containing a flame retardant material in the form of an oxidized condensate of a tetrakis hydroxyalkyl phosphonium salt with at least one of ammonia and nitrogenous compounds containing one or more amine groups.
In an embodiment, the nitrogenous compound may be selected from urea, ammonia, thiourea, biuret, melamine, ethylene urea, guanidine, and 2-cyanoguanidine.
In an embodiment, the tetrakis hydroxyalkyl phosphonium salt may be a tetrakis hydroxymethyl phosphonium salt.
In an embodiment, the flame retardant cellulose fiber may have a fineness of about 1.50 denier to about 1.55 denier and a fiber length of about 48 mm to about 52 mm, the aramid fiber may have a fineness of about 1.48 denier to about 1.52 denier and a fiber length of about 48 mm to about 52 mm, and the antistatic fiber may have a fineness of about 1.70 denier to about 2.70 denier and a fiber length of about 48 mm to about 52 mm.
In an embodiment, the first and second composite spun yarns may each be in the form of a plied yarn of two strands.
In an embodiment, the first and second composite spun yarns may each have a fineness of about 10 to about 80 English cotton count.
In an embodiment, the first and second composite spun yarns may be manufactured through a ring spinning method, an open-end spinning method, or an air-jet spinning method.
In an embodiment, the outer layer and the inner layer may have a basis weight of about 150 gsm to about 260 gsm and a basis weight of about 100 gsm to about 180 gsm, respectively, the intermediate layer may have a basis weight of about 60 gsm to about 100 gsm, and the outer layer, the intermediate layer, and the inner layer may have a combined basis weight of about 380 gsm to about 520 gsm. The unit of basis weight, gsm, refers to g/m2, and represents the number of grams per square meter.
According to another aspect of the disclosure, a multi-layer fabric, which is a multilayer fabric for personal protective equipment to protect a wearer from flame and/or arc flash, includes:
According to another aspect of the disclosure, provided is personal protective equipment formed of or formed by using the multilayer fabric according to the one aspect or another aspect of the disclosure.
These and other features, aspects, and advantages will be better understood with reference to the following description and appended claims and drawings.
The above and other aspects, features, and advantages of certain embodiments of the disclosure will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the FIGURES, to explain aspects of the present description. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list.
Hereinafter, based on a preferred embodiment, a multilayer fabric for personal protective equipment and personal protective equipment formed therefrom according to the disclosure will be described in detail, the multilayer fabric being used to manufacture personal protective equipment that not only can effectively protect a wearer from flame and/or arc flash, but also can provide excellent durability, comfortable wearing, and high activity functions. In the following description, detailed descriptions of well-known structures and functions are omitted so as not to obscure the gist of the disclosure.
Referring to
The outer layer 1 and the inner layer 3 may each be in the form of a woven fabric layer having a woven structure selected from an ordinary woven structure, a pile woven structure, and a gauze and leno woven structure. In particular, the outer layer 1 may preferably be a woven fabric layer with a twill weave in consideration of protection from flame and/or arc flash and wearability, and the inner layer 3 may preferably be a woven fabric layer with a plain weave in consideration of a contact with the skin of a wearer.
The intermediate layer 2 may be a nonwoven fabric layer including aramid fibers, the non-woven layer having a plurality of embossed dots or a plurality of embossed stripes. That is, the intermediate layer 2 may have a bumpy surface shape consisting of a plurality of embossed dots or a plurality of embossed stripes in relatively high relief, and microvoids may be formed between these dots and stripes. When the intermediate layer 2 is prepared in the form of a bumpy embossed nonwoven fabric layer, the multilayer fabric 10 according to the disclosure may have excellent lightness and thermal insulation properties with respect to the overall thickness of the multilayer fabric 10.
In an embodiment, each of the embossed dots may have a quadrangular shape with a length of one side of about 1.0 mm to about 5.0 mm and a height of about 0.5 mm to about 3.0 mm. For example, each of the embossed dots may have a square, rectangular, rhombus, or parallelogram shape having: a length of one side of about 1.2 mm to about 4.0 mm, for example, about 1.4 mm to about 4.0 mm, about 1.6 mm to about 4.0 mm, about 1.8 mm to about 3.6 mm, about 2.0 mm to about 3.6 mm, about 2.2 mm to about 3.8 mm, or about 2.2 to about 3.6 mm; and a height of about 0.6 mm to about 2.8 mm, for example, about 0.6 mm to about 2.6 mm, about 0.6 mm to about 2.4 mm, about 0.7 mm to about 2.4 mm, about 0.7 mm to about 2.2 mm, about 0.7 mm to about 2.0 mm, about 0.7 mm to about 1.8 mm, about 0.7 mm to about 1.6 mm, about 0.7 mm to about 1.4 mm, or about 0.8 mm to about 1.2 mm. Each of the embossed dots may have a circular shape with the same or similar area. The shape of the dots described herein in the present specification refers to a planar shape viewed from a vertical line perpendicular to the intermediate layer plane. The plurality of dots may be spaced apart at an interval of about 2.0 mm to 6.0 mm, for example, about 2.1 mm to about 5.8 mm, about 2.2 mm to about 5.6 mm, about 2.3 mm to about 5.4 mm, about 2.4 mm to about 5.2 mm, about 2.6 mm to about 5.0 mm, about 2.8 mm to about 4.8 mm, about 3.0 mm to about 4.6 mm, or about 3.2 mm to about 4.4 mm.
The dot density of the plurality of dots may be, per square meter of the intermediate layer 2, about 10,000 dots to about 100,000 dots, about 20,000 dots to about 90,000 dots, about 30,000 dots to about 80,000 dots, about 40,000 dots to about 75,000 dots, about 50,000 dots to about 70,000 dots, or about 60,000 dots to about 70,000 dots, in terms of forming an effective air insulation layer.
In an embodiment in which the intermediate layer 2 has embossed stripes instead of the embossed dots, each of the embossed stripes may have, for example, a width of about 1.0 mm to about 5.0 mm, for example, about 1.2 mm to about 4.0 mm, about 1.4 mm to about 4.0 mm, about 1.6 mm to about 4.0 mm, about 1.8 mm to about 3.6 mm, about 2.0 mm to about 3.6 mm, about 2.2 mm to about 3.6 mm, or about 2.2 mm to about 3.6 mm; and a height of about 0.5 mm to about 3.0 mm, for example, about 0.6 mm to about 2.8 mm, about 0.6 mm to about 2.6 mm, about 0.6 mm to about 2.4 mm, about 0.7 mm to about 2.4 mm, about 0.7 mm to about 2.2 mm, about 0.7 mm to about 2.0 mm, about 0.7 mm to about 1.8 mm, about 0.7 mm to about 1.6 mm, about 0.7 mm to about 1.4 mm, or about 0.8 mm to about 1.2 mm. The plurality of stripes may be spaced apart at an interval of about 2.0 mm to 6.0 mm, for example, about 2.1 mm to about 5.8 mm, about 2.2 mm to about 5.6 mm, about 2.3 mm to about 5.4 mm, about 2.4 mm to about 5.2 mm, about 2.6 mm to about 5.0 mm, about 2.8 mm to about 4.8 mm, about 3.0 mm to about 4.6 mm, or about 3.2 mm to about 4.4 mm. The stripe density of the plurality of stripes may be, per square meter of the intermediate layer 2, about 60 stripes to about 800 stripes, for example, about 70 stripes to about 700 stripes, about 80 stripes to about 650 stripes, about 90 stripes to about 600 stripes, about 100 stripes to about 550 stripes, about 120 stripes to about 500 stripes, or about 130 stripes to about 450 stripes, in terms of formation of an effective air insulation layer.
The nonwoven fabric layer constituting the intermediate layer 2 may be a spunlace nonwoven fabric layer or a needle punched nonwoven fabric layer in terms of effective and eco-friendly production and effective formation of dots and stripes by embossing. These dots and stripes described herein may be formed by, for example, passing the nonwoven fabric layer constituting the intermediate layer 2 between rolls having a suitable embossed pattern in relatively high relief.
The nonwoven fabric layer constituting the intermediate layer 2 may consist of aramid fibers in an amount of 70 wt % or more, for example, 80 wt % or more, 85 wt % or more, 90 wt % or more, or 95 wt % or more, based on the total weight of fibers constituting the nonwoven fabric layer.
The nonwoven fabric layer constituting the intermediate layer 2 may consist of at least one type of aramid fibers selected from meta-aramid fibers and para-aramid fibers, in an amount of 90 wt % or more, for example, 92 wt % or more, 94 wt % or more, 96 wt % or more, 97 wt % or more, or 99 wt % or more, based on the total weight of fibers constituting the nonwoven fabric layer. In terms of mechanical properties, thermal insulation properties, and durability, the nonwoven fabric layer may consist of para-aramid fibers in an amount of 97 wt % or more or 99 wt % or more, based on the total weight of fibers constituting the nonwoven fabric layer.
The outer layer 1, which primarily serves to block flame and/or heat, may be a woven fabric layer with a twill weave, and the inner layer 3, which is contact with the skin of a wearer, is a woven fabric layer with a plain weave in terms of durability and comfortable wearing.
The woven fabric layers of the outer layer 1 and the inner layer 3 may each include warp yarns and filling yarns to form a woven structure. The warp yarn may include a first composite spun yarn including aramid fibers, flame retardant cellulose fibers, and antistatic fibers. The filling yarn may include a second composite spun yarn including aramid fibers, flame retardant cellulose fibers, and antistatic fibers. To have different thermal shrinkage rates of the warp and filling yarns, the first and second composite spun yarns may preferably include constituent fibers at different ratios. The warp and filling yarns having different thermal shrinkage rates may be desirable in that an air insulating layer may be effectively formed by using these yarns by thermal shrinkage caused by thermal energy transmitted from arc flash and/or flame.
As such, the multilayer fabric 10 according to the disclosure may include the outer layer 1 and the inner layer 2 that are formed by using the first and second composite spun yarns having excellent heat resistance, hydrophilicity, and antistatic properties, and the intermediate layer 2 that is formed by using the aramid fibers having excellent heat resistance, mechanical properties, and durability. Furthermore, by providing the intermediate layer 2 with an embossed pattern structure in relatively high relief to form an air insulation layer with excellent thermal energy dissipation characteristics upon thermal shrinkage, the multilayer fabric 10 may effectively protect a wearer from flame and/or arc flash.
The outer layer 1 and the inner layer 3 may have a basis weight of about 150 gsm to about 260 gsm and a basis weight of about 100 gsm to about 180 gsm, respectively, the intermediate layer 2 may have a basis weight of about 60 gsm to about 100 gsm, and the multilayer fabric 10 including the outer layer 1, the intermediate layer 2, and the inner layer 3 may have a combined basis weight of 380 gsm to about 520 gsm. For example, the outer layer 1 may have a basis weight of about 160 gsm to about 250 gsm, about 170 gsm to about 240 gsm, about 180 gsm to about 230 gsm, about 190 gsm to about 220 gsm, about 200 gsm to about 230 gsm, or about 210 gsm to about 225 gsm. For example, the inner layer 3 may have a basis weight of about 110 gsm to about 170 gsm, about 115 gsm to about 160 gsm, about 120 gsm to about 150 gsm, about 125 gsm to about 140 gsm, or about 125 gsm to about 135 gsm. For example, the intermediate layer 2 may have a basis weight of about 65 gsm to about 95 gsm, about 70 gsm to about 90 gsm, or about 75 gsm to about 85 gsm. The lightweight multilayer fabric 10 including the outer layer 1, the intermediate layer 2, and the inner layer 3 may have a combined basis weight of about 390 gsm to about 510 gsm, about 400 gsm to about 500 gsm, about 410 gsm to about 490 gsm, about 420 gsm to about 480 gsm, or about 420 gsm to about 440 gsm.
As such, the multilayer fabric 10 according to the disclosure may include the outer layer 1 and the inner layer 2 that are formed by using the first and second composite spun yarns having excellent heat resistance, hydrophilicity, and antistatic properties, and the intermediate layer 2 that is formed by using the aramid fibers having excellent heat resistance, mechanical properties, and durability. Furthermore, by providing the intermediate layer 2 with an embossed pattern structure in relatively high relief to form a lightweight air insulation layer with excellent thermal energy dissipation characteristics upon thermal shrinkage, the multilayer fabric 10 may effectively protect a wearer from flame and/or arc flash. Therefore, use of the multilayer fabric 10 according to the disclosure may lead to the preparation of personal protective equipment categorized into HRC level 4 that not only effectively protects a wearer from flame and/or arc flash, but also provides comfortable wearing and high activity functions.
In the three-layer multilayer fabric 10 for personal protective equipment as described above, the first and second composite spun yarns of the outer layer 1 and the inner layer 3 may be prepared by mixing and spinning short fibers, i.e., aramid fibers, flame retardant cellulose fibers, and antistatic fibers in the form of staple fibers, in an appropriate ratio. Here, the aramid fibers, the flame retardant cellulose fibers, and the antistatic fibers may be in the form of staple fibers.
When spinning for the preparation of the first and second composite spun yarns for the outer layer 1 and the inner layer 3, the weight ratio of the aramid fibers:the flame retardant cellulose fibers:the antistatic fibers may be, for example, 45 to 70:30 to 70:1 to 5, and for example, 47 to 68:32 to 65:1.5 to 4.5, 49 to 66:34 to 60:1.8 to 4, or 52 to 64:36 to 58:1.6 to 3.8.
The mixing ratio may be selected to maximize the benefits of the aramid fibers and the flame retardant cellulose fibers and minimize shortcomings thereof to ensure fireproof properties and antistatic properties. That is, when the mixing ratio is adjusted within the ranges above, the dyeability and wearability may be improved while adjusting the degree of resistance to flame and/or arc flash, mechanical properties, and antistatic properties. That is, the present inventors have found out an optimal mixing ratio of the flame retardant cellulose fibers, the aramid fibers, and the antistatic fibers to make the most of flame retardant cellulose fiber materials and to compensate for weaknesses or drawbacks of the aramid fibers, and thus have succeeded in obtaining a composite spun yarn provided with high fastness, elasticity, lightness, warmth retaining properties, wearability, sweat absorbing and quick drying properties, antistatic properties, and resistance to flame and/or arc flash. That is, the present inventors have mixed multiple high-performance synthetic fibers, man-made fibers, and/or natural materials, and the like while using the aramid fibers as a main material, using general and special spinning methods, and thus have succeeded in obtaining a differentiated and improved composite spun yarn that maximizes the performance of the aramid fibers and compensate for the weaknesses of the aramid fibers in elasticity, touch, dyeing properties, and monotony of appearance patterns. For example, it may need to increase the total content of the aramid fibers and the flame retardant cellulose fibers to improve resistance to flame and/or arc flash, flame propagation blocking properties, and durability. With the high content of the aramid fibers, fireproof properties may be increased, but the cost excessively rises, and the wearability and dyeing properties may deteriorate when the aramid fibers are manufactured into a fabric. Therefore, a portion of the aramid fiber content may preferably be replaced with the flame retardant cellulose fibers to obtain the comfortable wearability and dyeing properties as well as to keep high fireproof properties. Here, an appropriate replacement ratio may be achieved by using the aforementioned weight ratio.
Among the aramid fibers, the meta-aramid fiber may have relatively flexible molecular chains and excellent heat resistance compared to the para-aramid fiber. That is, the meta-aramid fiber may be a fiber consisting of fully aromatic polyamide polymer in which a benzene ring is linked with an amide group at a meta position, and may have a melting point of 320° C. or higher and excellent heat resistance and flame retardant properties. The meta-aramid fiber has high heat resistance and tensile strength due to strong molecular structures and high crystallinity dense structures, but has a great limitation in activity when worn due to poor elasticity. Also, it has a disadvantage of not being dyeable well. Examples of the meta-aramid fiber include those available under the tradename NOMEX from Dupont, which are manufactured from poly(m-phenylene isophthalamide). The poly(m-phenylene isophthalamide) may be a homopolymer resulting from the polymerization of m-phenylene diamine and isophthaloyl chloride, or a copolymer resulting from the incorporation of small amounts of other diamines to m-phenylene diamine or small amounts of other diacid chlorides to isophthaloyl chloride. The meta-aramid fiber that can be used to manufacture the composite spun yarn of the disclosure may include those commercially available under the registered tradename of NOMEX from Dupont and the registered tradename of CONEX from Teijin.
Examples of the para-aramid fiber that can be used to manufacture the composite spun yarn according to the disclosure include those commercially available under the registered trandename of KEVLAR from Dupont, which is manufactured from poly(p-phenylene terephthalamide), the registered tradename of HERACRON from Kolon, and the registered tradename of ALKEX from Hyosung Advanced Materials.
The flame retardant cellulose fiber may be a flame retardant cellulose rayon fiber containing a flame retardant material in the form of an oxidized condensate of a tetrakis hydroxyalkyl phosphonium salt with at least one selected from the group consisting of ammonia and nitrogenous compounds containing one or more amine groups. The nitrogenous compounds may be selected from the group consisting of urea, thiourea, biuret, melamine, ethylene urea, guanidine, and 2-cyanoguanidine. The tetrakis hydroxyalkyl phosphonium salt may be a tetrakis hydroxymethyl phosphonium salt. The flame retardant cellulose fiber is derived from natural pulp and has high hydrophilicity, and may thus improve hygroscopicity, breathability, and comfortable wearability and comfort by preventing natural static electricity. The fiber is easy to blend with other fibers, and thus is highly efficient when it comes to functions and costs, and is beneficial in being easily dyed using acid dyes, reactive dyes, disperse dyes, and the like. The flame retardant cellulosic fiber is commercially available, for example, from Lenzing AG under the tradename of LENZING™ FR. Using the flame retardant cellulose fiber having high hydrophilicity improves flame retardant properties, hygroscopicity, and breathability, and also prevents the generation of static electricity, and thus may enhance the wearability of personal protective equipment manufactured by using woven fabrics obtained from the composite spun yarn. In particular, when the hydrophilic flame retardant cellulose fibers mainly arranged on the surface of the composite spun yarn according to an air-jet spinning method, personal protective equipment formed by using the multilayer fabric 10 that is manufactured by using the composite spun yarn may be comfortable to wear, may not burn easily by flame, and may effectively protect a wearer from heat stress and arc flash.
The antistatic fiber that may be used in the disclosure may be mixed to prevent the static electricity. Specific examples thereof include an antistatic fiber (available under the tradename of MIPAN corona) in which a carbon fiber is used as a core component and a nylon or polyester is used as a sheath component surrounding the core component by performing conjugate spinning to manufacture the antistatic fiber, and an antistatic fiber (available under the tradename of ELEX) in which a copper (copper sulphate) coating is applied to an acrylic fiber base.
The flame retardant cellulose fiber may have a fineness of about 1.50 denier to about 1.55 denier and a fiber length of about 48 mm to about 52 mm, the aramid fiber may have a fineness of about 1.48 denier to about 1.52 denier and a fiber length of about 48 mm to about 52 mm, and the antistatic fiber may have a fineness of about 1.70 denier to about 2.70 denier and a fiber length of about 48 mm to about 52 mm. The fiber length and fineness of the raw material short fibers have a great influence on the tensile strength of the composite spun yarn manufactured therefrom. The longer the fiber length of the short fibers, the stronger the binding force due to the twist between the short fibers, and thus the tensile strength of the composite spun yarn increases.
The first and second composite spun yarns may each be in the form of a plied yarn of two strands, and may have a fineness of about 10 to about 80 English cotton count, for example, about 20 to about 60 English cotton count, a fineness of about 25 to about 50 English cotton count, a fineness of about 30 to about 50 English cotton count, or a fineness of about 30 to about 45 English cotton count. The multilayer fabric 10 including the outer layer 1 and the inner layer 3 manufactured therefrom may have excellent dyeing properties. Also, the multilayer fabric 10 manufactured by using the first and second composite spun yarns may have similar wearability and soft feeling to general fabrics manufactured by using general regular fibers without containing the aramid fibers, and may be less expensive than special fabrics manufactured by using the aramid fibers 100%.
The first and second composite spun yarns described above may be manufactured through a traditional ring spinning method as well as through new technology spinning methods such as an open-end spinning method or an air-jet spinning method.
First, a method for manufacturing first and second composite spun yarns according to an embodiment, using a traditional ring spinning method will be described.
The commercially purchased aramid fibers, the flame retardant cellulose fibers, and the antistatic fibers may be mixed in the mixing ratios above, and then subjected to a blowing process. The resultant obtained in the form of a sheet by the blowing process may be put into a carding machine and subjected to a carding process through the first to third rounds to form a card sliver, which is a fiber aggregate. Afterwards, in order to obtain a high quality spun yarn, a combing process for manufacturing combed yarns may be performed by adjusting the content of fibers that are too short from the card sliver and by removing fiber debris or dust attached to the fibers. A drawing process of combining multiple strands of sliver obtained therefrom into a single strand of sliver may be performed. A roving process of further drafting the sliver obtained from the drawing process and manufacturing the fiber in the roving state may be performed. A spinning process, in which the roving manufactured through the roving process is made into thin threads with a predetermined thickness, the fiber bundles arranged side by side are twisted and interlaced in three dimensions to increase the cohesive force between the fibers and to maintain the strength of the threads, may be performed. The composite spun yarns that have undergone the spinning process may be wound on a bobbin or cone. If needed, a humidity provision process, in which a constant level of humidity is applied to the composite spun yarn wound on a bobbin or cone, may be performed to optimize the conditions of the spun yarns. A doubling and twisting process, in which two or more composite yarns are combined into a single strand to increase the tensile strength of the composite yarn manufactured through the above process, may be performed. The composite spun yarn manufactured through the doubling and twisting process may be wound on a bobbin or cone. If needed, a humidity provision process, in which a constant level of humidity is applied to the composite spun yarn wound on a bobbin or cone, may be performed to optimize the conditions of the spun yarns. The composite spun yarn manufactured in this way may be in the form of cheese or skein.
Other than the ring spinning method, the first and second composite spun yarn according to an embodiment may be manufactured by using a general core spinning method, an air-jet spinning method, or an open-end spinning method.
When using an air-jet spinning method, the flame retardant cellulose fibers, the aramid fibers, and the antistatic fibers are mixed at the mixing ratio described above, and a sliver obtained through the drawing process of the aforementioned ring spinning method or a roving obtained through the roving process are applied into an air-jet vortex spinning frame to be drafted by passing through draft portions consisting of draft rollers, so as to obtain an air-jet composite spun yarn. The obtained air-jet composite spun yarn may have 30 to 40 yarn counts and consist of core fibers and wrapping fibers. This type of air-jet spun yarn may improve anti-pilling and dyeing properties.
The first and second composite spun yarns thus prepared may be used to form woven fabric layers that constitute the outer layer 1 and the inner layer 3.
A method of weaving a woven fabric with the aforementioned woven structure as a woven fabric used to form the outer layer 1 and the inner layer 3, and a method of manufacturing a nonwoven fabric layer used to form the intermediate layer 3, e.g., a spunlace nonwoven fabric manufacturing method or a needle punched nonwoven fabric manufacturing method, are well known to those skilled in the art, and thus description thereof will be omitted.
Those skill in the art would combine the outer layer 1, the intermediate layer 2, and the inner layer 3, for example, by quilting in an appropriate manner using a sewing machine or a specialized quilting system. However, generally, no other padding materials exist between the outer layer 1 and the intermediate layer 2 or between the intermediate layer 2 and the inner layer 3.
The multilayer fabric for personal protective equipment according to the disclosure with the aforementioned characteristics may be used as multilayer fabric for manufacturing work clothes or uniforms that can effectively protect workers exposed to high-temperature environments, such as oil fields, gas fields, manufacturing plants for petrochemical products, steel mills, manufacturing plants for metal alloys, manufacturing plants for metal-forged products, and thermal power plants; or work clothes or uniforms for firefighters, military personnel, welders, casting operators, and the like.
Hereinafter, the disclosure will be described in more detail through the following Examples and Comparative Examples. The following Examples are merely examples to explain the disclosure in more detail, and are not intended to limit the scope of protection of the disclosure.
52 parts by weight (abbreviated as ‘pbw’) of meta-aramid fibers having a fineness of about 1.50 denier and a fiber length of about 51 mm (NOMEX® by DuPont), 40 parts by weight (pbw) of flame retardant cellulose fibers having a fineness of about 1.53 denier and a fiber length of about 51 mm (LENZING™ FR by Lenzing AG), and 2.3 parts by weight (pbw) antistatic fibers having a fiber length of about 51 mm (MIPAN Corona™ by HYOSUNG TNC) were mixed to obtain slivers through the aforementioned blowing, carding, combing, and drawing processes.
In an air-jet spinning type Murata Vortex Spinning System (Murata Vortex 861 Air-jet Spinning Machine by Murata Machinery), the slivers were passed through four pairs of draft portions, drafted at a draft ratio of about 150 to about 260, and supplied to the vortex spinning frame to prepare air-jet composite spun yarns. Two strands of the composite spun yarn thus prepared were plied to form a composite spun yarn in the form of plied yarns (fineness: about 40 English cotton count (Ne)). When manufacturing a multilayer fabric of Example 1, the resulting composite spun yarn was used as a raw material to manufacture a fabric forming an outer layer and an inner layer.
Composite spun yarns to be used as warp yarns and filling yarns when weaving an outer layer and an inner layer of multilayer fabrics of Examples 1 to 3 and Comparative Examples 1 to 3 were mixed at a weight ratio summarized in Table 2, so as to obtain composite spun yarns by the same method and numerical values described in Preparation Example 1.
A commercially purchased para-aramid fiber spunlace nonwoven fabric was passed through a roll equipped with an embossed protrusion pattern to obtain a para-aramid spunlace nonwoven fabric having an embossed dot pattern in relatively high relief with the standards summarized in Table 2 on one surface of the nonwoven fabric. This nonwoven fabric was used as an intermediate layer of a multilayer fabric of Examples 1 to 3.
A commercially available para-aramid fiber nonwoven fabric having a basis weight of about 180 gsm without an embossed dot pattern was used as an intermediate layer when weaving a multilayer fabric of Comparative Example 1.
By quilting an outer layer, an intermediate layer, and an inner layer that are formed of raw materials and having standards summarized in Table 2, a three-layer fabric in which these layers were laminated was manufactured. Here, meta-aramid yarns were used for quilting.
The outer layer and the inner layer of Example 2 were used, but as the intermediate layer, a commercially available para-aramid fiber nonwoven fabric (Preparation Example 9) with a basis weight of about 180 gsm without an embossed dot pattern was used. By quilting these layers, a three-layer fabric was obtained.
For the three-layer fabrics of Examples 1 to 3 and Comparative Example 1, the arc rating (ATPV) was measured according to the procedures and conditions specified in the ASTM F1959/F1959M Electric Arc Test, commonly referred to as “Open Arc Test”. Results thereof are shown in Table 3.
Referring to Tables 2 and 3, it was found that, since the multilayer fabric of the disclosure was lightweight but had an Arc Rating in excess of 40, the multilayer fabric has met the requirements of HRC level 4. In comparison, the multilayer fabric of Comparative Example 1 also met the requirements of HRC level 4, but had a problem that the total basis weight thereof was about 530 gsm, which is about 100 gsm larger than the total basis weight of 430 gsm of the multilayer fabric of Example 2. Therefore, since the fabric of Comparative Example 1 had poor lightness, personal protective equipment formed therefrom would have poor wearability in high-temperature environments. In comparison, the multilayer fabrics of Examples 1 to 3 of the disclosure would be able to exhibit performance to meet the requirements of HRC level 4 even at a small basis weight. Therefore, since the multilayer fabrics of Examples 1 to 3 had excellent lightness as well as excellent performance against arc flash, personal protective equipment formed therefrom would have good wearability in high-temperature environments and provide effective protection against arc flash.
Reference throughout the specification to “an embodiment”, “another embodiment”, “some embodiments”, and so forth, means that a particular element (e.g., feature, structure, step, or characteristic) described in connection with the embodiment is included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments.
The endpoints of all numerical ranges directed to the same component or property are inclusive of the endpoints, are independently combinable, and include all intermediate points.
Unless defined otherwise, technical and scientific terms used herein have the same meaning as is commonly understood by one of skill in the art to which this disclosure belongs.
While particular embodiments have been described above, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
According to the one or more embodiments, a multilayer fabric for personal protective equipment adopts a multilayer fabric structure with an intermediate layer having embossed dots or embossed stripes to form an effective air insulating layer during exposure to arc flash as well as under normal conditions. Here, the intermediate layer may be prepared as a nonwoven fabric layer by using aramid fibers having excellent heat insulation, heat resistance, and mechanical properties. Furthermore, an outer layer and an inner layer of the multilayer fabric use, as a warp yarn and a filling yarn, a first composite spun yarn and a second composite spun yarn having excellent heat insulation, heat resistance, and mechanical properties as well as appropriate hydrophilicity, wherein these first and second composite spun yarns are adjusted to have different heat shrinkage rates, thereby more effectively forming an air insulation layer upon exposure to arc flash. Therefore, the multilayer fabric may effectively protect a wearer from flame and/or arc flash by improving insulation effect against heat, i.e., the ability to block thermal energy, generated from flame and/or arc flash and transmitted to the wearer through mechanisms such as conduction. As such, the multilayer fabric may be used as a material having excellent lightness, mechanical properties, and durability as well as appropriate hydrophilicity to form an outer layer and an inner layer. Therefore, use of the multilayer fabric according to the disclosure may lead to the preparation of personal protective equipment categorized into HRC level 4 that not only effectively protects a wearer from flame and/or arc flash, but also provides comfortable wearing and high activity functions.
A multilayer fabric prepared by using the multilayer fabric for personal protective equipment according to the disclosure may effectively protect workers in environments exposed to high temperatures from flame and/or arc flash. Therefore, use of the multilayer fabric of the disclosure having the aforementioned characteristics may lead to the preparation of various types of personal protective equipment. For example, personal protective equipment, such as work clothes, hoods, etc., that can protect workers in environments where they are exposed to high temperatures and/or high voltage electricity, such as oil fields, gas fields, steel mills, power plants, or substations; manufacturing plants for petrochemical products, alloys, or metal-forged products; fire scene or welding workplace.
It should be understood that embodiments described herein should be considered in a descriptive sense only and not for purposes of limitation. Descriptions of features or aspects within each embodiment should typically be considered as available for other similar features or aspects in other embodiments. While one or more embodiments have been described with reference to the figures, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the disclosure as defined by the following claims.
