Flame-retardant fabrics containing cotton substitutes

Abstract

The present disclosure relates to a flame retardant (FR) treated fabric comprising yarns formed from a blend of natural and / or synthetic fibers, the fabric further comprising FR treated lyocell fibers, where the FR treatment is a non-cellulosic reactive FR treatment, and the FR treated lyocell fibers are rendered less fibrillated, e.g., whereby at least some of the hydroxyl groups are crosslinked with a reactive resin.

Description

Technical Field

[0001] The present invention relates to heat-resistant and flame-retardant fabrics and a method for producing the same. The fabric includes a cellulose-based cotton substitute having heat-resistant and flame-retardant properties.

Background Art

[0002] Many specialized occupations require individuals to be exposed to the risk of extreme heat and / or flames. Typical examples are industrial workers, firefighters, police officers, and military personnel. Such personnel receive the provision of appropriate flame-resistant clothing as much as possible. These clothing are clearly different from ordinary everyday clothing because they are at least partially composed of flame-retardant fabrics.

[0003] The clothing must meet the requirements regarding the lowest thermal performance, such as flame retardancy and / or heat resistance, resistance to molten metal, electrical arc resistance, a low rate (presumed) of body burns in a thermal manikin test, a limited afterglow time, high resilience to combustion, and protection against radiant heat.

[0004] In addition to specialized flame-resistant clothing, more general work clothing often requires high flame resistance, which can be certified by one or more standards. Requirements regarding other important performances are tensile strength and tear strength, elongation at break, abrasion resistance, snagging resistance, and resistance to penetration by water and liquid chemicals.

[0005] Furthermore, it is considered important for the clothing to achieve appropriate comfort, for example, by allowing steam to be carried out from the body and ensuring that the clothing is not too stiff. Also, the clothing must be durable in the sense that the parameters disclosed above continue for at least the intended or guaranteed product life. This can be defined by several washing cycles.

[0006] Furthermore, garments must be printable or dyeable with durable results, for example, so that they can be dyed to increase their visibility. ISO 11612 is a commonly used standard for performance requirements for flame-retardant and fire-resistant garments made from flexible materials.

[0007] A well-known treatment for making cellulose fibers or fabric articles containing cellulose fibers flame-retardant is the Proban® treatment. This treatment involves pre-reacting the fabric article with urea and padding it with an aqueous solution containing a tetrakishydroxyalkylphosphonium (THP) salt adjusted to a pH of 5-8.

[0008] THP does not substantially react with cellulose fibers, nor with fabric articles containing said fibers; instead, it forms a coating network around and / or over the molecular structure of the cellulose fibers. Therefore, the Proban® treatment is a non-cellulose reactive treatment, meaning there is substantially no chemical reaction between THP and cellulose fibers. Alternative non-cellulose reactive treatments for Proban and THP can achieve the same effect.

[0009] An alternative flame-retardant treatment is treatment with N-methylolphosphonate compounds, such as N-methyloldialkylphosphonopropionamide. Commercially, such treatments are offered under the brands Pyrovatex® CP and Aflammit® KWB. In this case, the flame-retardant compound is grafted onto the cellulose by a reaction on the C(6) hydroxyl group of cellulose, resulting in grafted protective phosphonopropionamide molecules on the outside of the cellulose fibers. Thus, this is an example of a cellulose-reactive phosphorus-containing compound, as a reaction exists between cellulose and the phosphorus-containing compound. Therefore, the Pyrovatex treatment has essentially different chemical properties and mechanisms from the Proban process.

[0010] Pyrovatex and Proban were developed to make cotton flame-retardant, but the resulting fabrics have many associated problems. U.S. Patent Application Publication 3816068A1 discloses a flame retardant for cellulose fabrics and describes the drawbacks of the Pyrovatex process. The drawbacks of Pyrovatex-treated fabrics include incompatibility with many other treatments and their tendency to hydrolyze over time. Pyrovatex-treated products require washing at least once a year after production (regardless of use) to prevent hydrolysis and the associated unpleasant odors. Typically, the degree of flame retardancy achieved is more limited than with THP treatment, and the process is suitable for up to 20% synthetic fibers. European Patent Application Publication 0709518A1 discloses Proban-treated cotton fabrics. This document aims to solve the problem of stiffness in Proban-treated cotton.

[0011] There are also fibers that are inherently flame-retardant and do not require treatment to achieve this flame retardancy. Such fibers, including para-aramid and meta-aramid fibers, PPS, PBO, and PBI, may be called flame-retardant fibers. Other flame-retardant fibers that are inherently flame-retardant include, for example, fibers extruded from a fiber spinning dope to which flame-retardant additives have been added before spinning as a masterbatch. Fibers thus obtained include FR lyocell, modacrylic, FR polyester, and FR polyamide FR. Hereafter, the term flame-retardant (FR) is used to refer to fibers that have been treated to be flame-retardant, as opposed to those that have inherent flame-retardant properties.

[0012] A growing concern in the field of clothing manufacturing is the selection of environmentally friendly options. While natural fibers, such as cotton, may be advantageous over synthetic fibers in some respects, it is well known that cotton has relatively strong influences regarding the requirements for its production, particularly water use. It is desirable to provide cotton substitutes that can at least partially replace cotton or other natural fibers in flame-retardant clothing.

[0013] One cotton substitute made from wood chip cellulose from a reliable source is lyocell. It is a similar material to rayon but without the drawbacks of the viscose process. It also has a considerably lower water footprint than cotton, using up to 95% less water. However, so far, it has not been possible to adequately replace cotton with lyocell, which requires durability and flame retardancy in combination with other workwear requirements. In particular, lyocell's tendency to fibrillate has been seen as a major drawback. [Overview of the project] [Problems that the invention aims to solve]

[0014] It is desirable to provide a substitute for ordinary FR cotton that has a smaller environmental footprint and still meets at least certain quality requirements expected of protective clothing. [Means for solving the problem]

[0015] The present invention provides a flame-retardant (FR) treated fabric comprising yarn formed from a mixture of natural and / or synthetic fibers, the fabric further comprising FR-treated lyocell fibers, where the FR treatment is a non-cellulose reactive FR treatment, and the FR-treated lyocell fibers are low fibrillation. Hereinafter, the term “lyocell” is used to refer to artificial cellulose-based cotton substitutes. In particular, these may represent cellulose fibers obtained by organic solvent spinning processes, but the present invention may also be applicable to several cellulose fibers that can be obtained by viscose processes. Lyocell, for example, Tencell® products available from Lenzing AG are well known, but other similar cellulose-based cotton substitutes are available and may be equally applicable. Lyocell may exist in the form of short artificial fibers, long artificial fibers, or as filaments or ribbons. Furthermore, in this context, references to natural and synthetic fibers are intended to exclude lyocell fibers, i.e., these are lyocell and others. Depending on the required properties, any amount of lyocell may be present. In particular, 1 to 99% by weight of lyocell, preferably 10 to 70% by weight, more preferably 15 to 50% by weight of lyocell, or 20 to 35% by weight of lyocell may be present.

[0016] It is well known that lyocell is prone to fibrillation. It is also understood that lyocell has reduced tensile strength when it absorbs water, i.e., when it is in a wet fabric state. As a result of investigations, it has also been revealed that, in the context of the present invention, fibrillation is further aggravated by performing a THP-type FR treatment. In a wet state, water can penetrate the bundles of lyocell fibrils, resulting in exposure of the fibrils on the fiber surface. The rate of fibrillation increases with increasing pH and temperature, as is experienced during normal FR treatments. Unlike cotton, lyocell does not crosslink naturally, and therefore it is desirable to provide a finish that at least partially compensates for the increase in fibrillation. For lyocell-like materials, it is thought that the fibrils are at least partially held together by hydrogen bonds between adjacent fibrils. For example, a reduction in the degree of hydrogen bonding in the presence of water or as a result of certain treatments can lead to an increase in fibrillation.

[0017] Anti-fibrillation finishes can be achieved on fabrics by applying appropriate additives. Preferably, the additives are substances that react with the hydroxyl groups of cellulose to stabilize the fibrils. This may be by increasing the presence of hydrogen bonds or by forming covalent bonds, thereby achieving improved crosslinking of the fibrils. Additives that crosslink by forming covalent bonds to the hydroxyl groups of cellulose materials may be called reactive resins, thermosetting resins, or easy-care finishes. Reactive resins include ethylene urea formaldehyde, propylene urea formaldehyde, methylated uron formaldehyde, and dimethylol dihydroxyethylene urea (DMDHEU) modified resins. The latter is a preferred choice. Those skilled in the art will be well aware that alternatives and equivalents to the above may also be applied. In this context, low fibrillation can be qualitatively determined by the presence of crosslinking to the hydroxyl groups of lyocell. Alternatively, this can be experimentally determined, for example, by pilling, abrasion, color retention, or other tests specified below.

[0018] In one embodiment, the natural fibers include FR cotton. The fabric may have the overall feel of a cotton fabric, with some of the cotton replaced by a lyocell substitute. Up to approximately 50% of the cotton can be replaced without significantly affecting the overall performance of the fabric. Nevertheless, the softness of the fabric is considerably increased, and it is generally experienced to be very comfortable during use. However, generally, when cotton is replaced with lyocell, some amount of stronger fibers may be needed, for example, synthetic fibers that offset the loss of certain properties or complement the lyocell in other ways. In particular, lyocell generally has a slightly lower wet strength than cotton, but its strength is considerably reduced after THP processing. Therefore, polyester can be added to the fiber blend to compensate. However, it is not ruled out that other natural fibers, for example, more or less of linen or wool may be present.

[0019] In one embodiment, the synthetic fiber includes polyester. Other synthetic fibers, such as polyamide or aramid, may also be intended, and it is not excluded that further smaller volumes of high-performance synthetic fibers may be included. In one embodiment, the synthetic fiber includes recycled polyester. One preferred source of recycled polyester is Repreve® from Unifi Inc., which is mechanically recycled polyester. Chemically recycled polyester may also be used. Recycled polyester has many attractive advantages, such as a 45% reduction in energy consumption compared to virgin polyester; a roughly 20% reduction in water consumption compared to virgin polyester; and a more than 30% reduction in greenhouse gas emissions compared to virgin polyester. Recycled polyester has excellent strength properties and adds durability, although it does not respond to many FR treatments. Synthetic fibers can exist in various forms, including short artificial fibers, long artificial fibers, and filaments.

[0020] It is understood that a variety of possible fabrics can be envisioned, including woven and knitted fabrics. Woven fabrics are preferred. Woven fabrics can have any suitable composition and are formed from warp and weft threads in a selected weave or pattern. Both warp and weft threads may be the same or different in terms of their composition, weight, etc. Each thread may be a spun yarn. A spun yarn is understood to contain a close blend of constituent fibers. Some ends of the yarn may be twisted together to form a ply. A ply may also be formed by twisting together spun fibers having one or more filaments.

[0021] In one embodiment, lyocell fibers may be present only in the warp threads. This has been found to be most suitable when the lyocell has been adequately stabilized against fibrillation by a finishing process. In this case, the lyocell may be further enhanced by the presence of synthetic fibers also blended into the warp threads. When lyocell is subjected to fibrillation, it may be preferable to include lyocell only in the weft threads instead, for example, to reduce its exposure to the outer surface of the fabric in a twill weave.

[0022] In certain embodiments, the warp threads include lyocell fibers, synthetic fibers, and natural fibers. Thus, the blend may consist of lyocell, cotton, and polyester synthetic fibers, which together constitute at least 95% of the warp threads. In one embodiment, 50% of the warp threads may consist of lyocell, with equal amounts of cotton and polyester making up the remainder. In one embodiment, these may preferably be present in the warp threads in a weight percentage ratio of approximately 50 / 25 / 25, respectively.

[0023] It has been observed that certain relationships exist between different characteristics of fabrics that yield optimized results. In particular, it can be noted that increased use of lyocell requires a balanced increase in the amount of stronger synthetic fibers needed to compensate for the loss of strength of lyocell (especially after FR treatment). Corresponding to the increased lyocell, synthetic fibers are present in the yarn direction. In the case of synthetic fibers that are neither essentially FR nor FR-treated, the total amount of synthetic fibers that can be introduced depends on the degree of FR treatment of the natural fibers and lyocell. For reasons further explained below, a limited degree of FR treatment may be preferable to avoid excessive fibrillation. Thus, the overall amount of non-FR synthetic fibers that can be present in the mix can be limited. For this reason, the above 50 / 25 / 25 mix in the warp has been found to be rather appropriate, and its obvious variations achieve the same favorable effect.

[0024] However, when synthetic fibers are introduced in one direction, the fabric can become unstable, for example, with respect to shrinkage. For this reason, a limited amount of synthetic fibers may be required in other weaving directions, for example, a 90 / 10 cotton / polyester blend may be suitable. A general cotton / lyocell / polyester blend of approximately 50 / 30 / 20 may result. It should be noted that generally, a low amount of synthetic fibers may be preferable, as their primary purpose is to reinforce strength, and synthetic fibers have a negative impact on the degree of FR of the overall fabric. Nevertheless, an amount of synthetic fibers exceeding the amount achievable for Pyrovatex-type treatments may be achieved.

[0025] In the case of polyester, up to 50% by weight of polyester may be present in the overall fabric. For other fibers, such as polyamide, up to 20% by weight may be present. The percentage of alternative fibers that remain below the upper limit for compatibility with THP FR treatment may be selected depending on the end use and is also within the scope of this application. For example, to provide desired strength in terms of softness, color retention, or to include a larger amount of environmentally friendly fibers.

[0026] In one embodiment, the weft yarn may include a dominant natural fiber, preferably 70% to 95% by weight of natural fiber, particularly cotton.

[0027] Any suitable weaving configuration may be contemplated, and those skilled in the art are well aware of the respective advantages of such weavings. In one embodiment, the fabric may be woven as a twill weave, preferably a 2 / 1 twill weave. A crepe weave may also be used, where it is desirable to achieve a particular drape or ensure that a particular yarn is provided exclusively on one side or the other. The fabric may also be a double cloth having distinct properties for each of the face cloth and the back cloth, a reversible fabric, or a fabric having two identical sides.

[0028] According to an important aspect of the present invention, the fabric includes an anti-fibrillation finish for preventing fibrillation of lyocell. As described above, lyocell does not crosslink naturally, and thus it is desirable to provide a finish that at least partially compensates for the increased fibrillation. Importantly, while the use of finished lyocell fibers is well known in preventing fibrillation, it has now been found that an unfibrillated finish is detrimental to the application of a flame retardant treatment to lyocell fibers. By using untreated lyocell fibers, i.e., lyocell fibers that have not been subjected to an anti-fibrillation treatment, an improved application of the FR treatment can be achieved. This has been found to be particularly true for Proban type (THP) treatments. Without being bound by theory, the presence of a crosslinked resin, such as formaldehyde, is thought to prevent the operation of the THP mechanism (which requires the formation of a coating network around and / or throughout the molecular structure of the lyocell fiber).

[0029] According to the present invention, the anti-fibrillation resin finish can be applied following the FR treatment. However, it has also been found that the FR treatment itself can have a negative effect on the subsequent anti-fibrillation finishing process. This is thought to be due to the steric hindrance of the hydroxyl groups as a result of the THP treatment. According to one aspect of the present invention, the degree of FR treatment is kept to a minimum. In this context, the amount of phosphorus in the final fabric can be kept below 2.5% by weight, preferably below 2.4% by weight or rather below 2.2% by weight. The values for nitrogen also reflect the degree of FR treatment and these can be kept below 1.7% by weight or below 1.6% by weight or rather below 1.5% by weight. These values have also been found to ensure proper FR compliance. Nevertheless, as described above, the reduction in the degree of FR treatment limits the overall capacity of the synthetic fibers that may be present in the blend in cases where those synthetic fibers are non-FR.

[0030] In one embodiment, the fabric further comprises a water and / or oil repellent finish. Suitable finishes include conventional PFAS (perfluorinated alkyl substances) finishes such as PTFE, Teflon® etc. Instead, the fabrics of the present disclosure can also be made with PFAS-free finishes and are thus more environmentally friendly.

[0031] As described above, the fabric can also include other fibers or yarns for specific technical purposes. For protective workwear, antistatic fibers can be included as fibers in the blend or as separate antistatic yarns or filaments. In one embodiment, the fabric can include antistatic fibers or filaments in an amount of 0.2% to 3% by weight. When antistatic artificial filaments are used, an amount of up to 5% by weight may be required depending on whether the antistatic fibers are distributed or localized.

[0032] An exemplary fabric according to the present invention, in the warp: 40 - 60% by weight, preferably approximately 50% by weight of lyocell, 15 - 35% by weight, preferably approximately 25% by weight of cotton; and 15-35% by weight, preferably about 25% by weight, of recycled polyester; and In the weft: 70-99% by weight, preferably about 90% by weight of cotton, 1-20% by weight, preferably about 10% by weight, of recycled polyester It may include.

[0033] The fabrics are preferably durable for at least 50 washes according to ISO 15797 without losing their required properties. These may include one or more of the following: • Color retention scores greater than 2 or 3 based on grayscale comparison with ISO 105-A02; • Exceeds the surface ignition criteria of ISO 11612 according to the test procedure of ISO 15025 (2000); • Exceeds the lower edge ignition criterion of ISO 11612 according to the test procedure of ISO 15025 (2000); • Tear strength exceeding 10N according to ISO 13937-2 (2000); • Tensile strength exceeding 300N according to ISO13934-1(2013). The fabric should also preferably exhibit abrasion resistance to more than 15,000 cycles, preferably more than 20,000 cycles, by the Martindale method, and should meet ISO 12947-2 for an applied force of 12 kPa.

[0034] The non-cellulose reactive treatment may preferably be any suitable such treatment based on a THP salt, for example, a Proban® treatment.

[0035] The present invention also relates to a method for producing flame-retardant and fire-retardant fabrics comprising a mixture of natural and / or synthetic fibers and lyocell fibers having reachable hydroxyl groups, the method comprising first subjecting the fabric to a non-cellulose reactive FR treatment, and subsequently finishing the fabric by applying a resin to stabilize the fibrillation of lyocell.

[0036] In this context, the term “reachable hydroxyl groups” is intended to refer to the fact that the lyocell fibers have not been treated with anti-fibrillation additives, such as crosslinking resins. According to the present invention, it has been shown that the presence of such additives prior to FR treatment can reduce the effectiveness of the treatment. For this reason, it is desirable that the FR treatment be performed on a fabric that has not yet been stabilized against fibrillation by a treatment that allows the lyocell fibers provided in the yarn to occupy hydroxyl groups.

[0037] Prior to FR treatment, the fabric may be pre-treated by one or more processes selected from the group: desizing, sculpting, bleaching, mercerizing, and dyeing, including reactive and non-reactive dyes.

[0038] The fabric can be any suitable fabric, including woven or knitted fabrics, and the method may involve first constructing the fabric from individual yarns before performing the FR treatment. In other words, the FR treatment is performed on the fabric rather than applied to the yarns themselves. Constructing the fabric may preferably involve weaving the yarns in the warp and weft in a twill weave. In one embodiment, lyocell is present in the yarn only in the warp direction.

[0039] Finishing a fabric by applying a resin may involve the use of any suitable chemical reaction to prevent fibrillation. Preferably, the resin is a substance that reacts with the hydroxyl groups of cellulose to stabilize the fibrils. Such resins may be called reactive resins, thermosetting resins, or easy-care finishes. Reactive resins include ethylene urea formaldehyde, propylene urea formaldehyde, methylated uron formaldehyde, and dimethylol dihydroxyethylene urea (DMDHEU) modified resins. The latter is a preferred choice, but equivalents and substitutes may be equally applicable. The finishing step may be completed, for example, by crosslinking the resin by the application of heat.

[0040] The finishing treatment may further include a water-repellent and / or oil-repellent treatment, preferably provided in a separate step, after the application of a resin to prevent fibrillation. Both treatments may be applied together, but for existing treatments, it has been found that better effectiveness is achieved by applying the anti-fibrillation finish first, followed by the water-repellent / oil-repellent finish. Heat treatment may be performed together for both treatments, but preferably the anti-fibrillation resin is crosslinked by heat treatment before initiating the water-repellent / oil-repellent finish. Suitable oil-repellent and / or water-repellent finishes include common PFAS (perfluoroalkylated substance) finishes, such as PTFE, Teflon®, etc. Alternatively, the fabrics of this disclosure may also be made with PFAS-free finishes, and are therefore more environmentally friendly.

[0041] The present invention also relates to garments manufactured by the methods described above or below in this specification.

[0042] This combination of materials results in a breathable, comfortable, durable (avoiding rapid fibrillation), FR, and environmentally friendly fabric. The advantageous range of cotton brings both sustainability and breathability to the fabric.

[0043] Several materials are particularly attractive for consideration in environmentally friendly products. Recycled materials, sustainable materials, and materials with low water scarcity have less environmental impact.

[0044] Flame retardancy (FR) is defined in this application to mean flame retardancy and / or heat retardancy given by treatment to filaments, fibers, yarns or fabrics. This can provide fabrics with a low rate of (estimated) body burns in thermal mannequin tests, limited afterflame time, high resilience to combustion, and protection against radiant heat, electric arcs and molten metals. For example, it can meet the performance requirements for flame retardant clothing made from flexible materials in ISO 11612. [Modes for carrying out the invention]

[0045] As a non-limiting example, the following process steps from source to product are described.

[0046] The following are examples of manufacturing process steps. First, artificial fibers are formed into yarn through spinning. Next, these threads are woven into an unbleached and undyed cloth according to the desired and optimal specifications. • Inspect unbleached and undyed fabrics. • Pre-treatment including desizing, sculpting, and bleaching. • In a further pre-treatment step, the cotton and lyocell are mercerized. Next, the fabric is dyed in a continuous dyeing process that includes dyeing and color fixing. Next, the fabric is checked for color defects, and then it is put into the finishing process line. • One or two FR treatment steps involving fabric impregnation and ammonia curing can be performed. • The fabric is mechanically softened in an air tumbler to make it more flexible. • The product is spread on a tenter frame and treated with resin to prevent fibrillation. The fabric is then heat-treated to crosslink the added resin. • Further finishing is applied to achieve oil-repellent and water-repellent properties. • Heat-treat / slow-cool the product. • Sanforize the fabric to reduce shrinkage. Next, quality control is performed. This is followed by packaging and shipment to garment manufacturers, where the garments are shaped for specific uses, such as uniforms for a particular workplace.

[0047] Artificial fibers formed into yarn include cotton, lyocell, and recycled polyester. Cotton is a natural fiber that offers comfort and better moisture management than synthetic fibers. Cotton is a traditionally used fiber for FR-treated fabrics.

[0048] Lyocell is a synthetic cellulose fiber. Other alternative cellulose-based cotton substitutes exist, such as Livaeco®, Birla Modal®, Birla Excel®, Birla Viscose®, and Birla Spunshades®, offered by Birla Cellulose. Lyocell is an industrial and washable fiber that loses strength when wet. In fact, lyocell has similar strength to cotton when wet and is more durable than cotton. Compared to cotton, lyocell uses 95% less water. Lyocell is more comfortable than cotton with better moisture management and is generally smoother to the skin. However, it is a fibrillating fiber. For example, when wet, water penetrates into the inside of the fibril bundles, resulting in fibril exposure on the fiber surface. The rate of fibrillation increases with increasing pH and temperature.

[0049] (Recycled) polyester can be recycled mechanically or chemically. Polyester is used in FR-treated fabrics, which increases durability because it is a relatively stronger material, but it is also heavier than cellulose-based fabrics. Polyester cannot be made flame-retardant due to the chemical properties of Proban. Sustainability can be improved by using mechanically recycled polyester. The use of recycled polyester results in a 45% reduction in energy consumption compared to the use of virgin polyester and a roughly 20% reduction in water consumption compared to virgin polyester. Greenhouse gas emissions are reduced by more than 30% compared to virgin polyester.

[0050] For the exemplary EG9600 fabric, the following synthetic fibers were used to spin the yarn. Cotton (medium grade) • Count, 3.8~4.4 Micronair • Length: 27mm • Tenacity: 26-30 cN / tex Tencel Lyocell Standard • Count, 1.25 dtex • Length: 38mm • Tenacity, 38 cN / tex • Tenacity, moist, 31 cN / tex RePreve recycled polyester • Count, 1.3 dtex • Length: 38mm • Tenacity, 59 cN / tex Nega-Stat (registered trademark) P190 • Count, 39 / 6 dtex • Length = filament

[0051] An example of a fabric yarn composition is as follows: Warp threads: 50% lyocell 25% cotton; and 25% recycled polyester. Weft: 90% cotton; and 10% recycled polyester. AS twisted yarn: 75% cotton; 8% recycled polyester. 17% Negastat filament

[0052] EC9600 fabric is woven in a 2 / 1 twill weave with the above warp and weft threads. Antistatic threads are included in the weft at intervals of 1:20. The overall weight percentage of each fiber in the final fabric is: 50% cotton; 30% lyocell; 19% recycled polyester, 1% Negastat filament That is the case.

[0053] After single-pass THP treatment, the fabric was measured to have the following flame retardancy intrinsic values.

[0054] The amount of THP is measured by P,N analysis with the following results: EG9600: P2.1% N1.7% Traditional cotton products: P2.9% N1.9%.

[0055] Fabrics after FR treatment are still susceptible to fibrillation. Finishing the fabric after FR treatment with an appropriate resin prevents fibrillation of lyocell in the product. The resin is applied in a foulard process, which includes water removal by pressing and heating, followed by heat treatment to crosslink the resin. The term non-fibrillation, as used herein, is understood to mean substantial non-fibrillation and is interchangeable with low fibrillation. The application of a non-fibrillating resin results in a fabric with reduced fibrillation compared to the untreated fabric.

[0056] The second finishing step is required to give the fabric a water-repellent and / or oil-repellent finish with a fluorocarbon resin (FC) to meet ISO 13034. The resin and FC may be combined in one batch, or the resin and FC finish may be applied successively in a two-step process to improve fibrillation and prevent color loss. This two-step process reduces fibrillation after washing. A further improvement is to crosslink the resin first before applying the FC finish.

[0057] It can be washed according to the standard ISO 15797, 75°C, j criteria, resulting in reduced and homogeneous fibrillation. The fabric remains durable even after up to 50 rigorous washes according to ISO 15797, 75°C, j.

[0058] The final product has the following advantages: 50% environmentally friendly materials, • Durable and long-lasting, • 28% lower water footprint than traditional FR-treated fabrics. • 10% lower CO2 footprint than traditional FR-treated fabrics. Thanks to lyocell, it is very soft and breathable. • Low water vapor resistance (breathability) and good short-term vapor absorption, • Better performance than traditional FR-treated fabrics. Traditional FR-treated cotton fabrics feel stiff and sturdy, while EG9600 feels supple and soft against the skin. • FR performance equivalent to traditional FR-treated cotton fabrics. • Low pilling. [Examples]

[0059] Three batches of improved FR fabric were tested, and the properties measured after final finishing were reproducible and demonstrated to comply with the following technical specifications:

[0060] [Table 1]

[0061] The technical specifications of the fabric of the present invention are comparable to and match those of standard FR fabrics and alternative intrinsically flame-retardant fabrics known as Modal / Tencel® in terms of properties. The improved FR fabric of the present invention further offers improved comfort and a reduced carbon footprint. A comparison of the technical specifications is as follows:

[0062] [Table 2] The invention described in the original claims of this application is listed below. [1] A flame-retardant (FR) treated fabric comprising yarn formed from a mixture of natural and / or synthetic fibers, further comprising FR-treated lyocell fibers, wherein the FR treatment is a non-cellulose reactive FR treatment, and the FR-treated lyocell fibers are low fibrillation. [2] The fabric described in [1], which is a woven fabric containing warp and weft threads. [3] The fabric according to [1] or [2], wherein the natural fiber includes cotton. [4] The fabric according to any one of [1] to [3], wherein the synthetic fiber preferably comprises recycled polyester, polyamide and / or aramid. [5] The fabric according to any one of [2] to [4], wherein the lyocell fibers are present only in the warp threads. [6] The fabric according to [5], wherein the warp threads preferably comprise lyocell fibers, synthetic fibers, and natural fibers in a weight percentage ratio of approximately 50 / 25 / 25. [7] The fabric according to [5] or [6], wherein the weft yarn comprises a predominant, preferably 70% to 95% by weight, natural fibers. [8] A fabric as described in any one of [1] to [7], woven in a twill weave, preferably as a 2 / 1 twill weave. [9] The fabric according to any one of [1] to [8], further comprising an antifibrillation finish, preferably an antifibrillation additive, optionally a resin that can crosslink to the hydroxyl groups of the FR lyocell, preferably a DMDHEU resin.

[10] A fabric according to any one of [1] to [9], further comprising a water-repellent and / or oil-repellent finish, preferably comprising a fluorocarbon.

[11] Preferably, the fabric according to any one of [1] to

[10] further comprises antistatic fibers in an amount of 0.2% to 5% by weight.

[12] In the warp threads: 40-60% by weight, preferably about 50% by weight of lyocell, 15-35% by weight, preferably about 25% by weight of cotton; and 15-35% by weight, preferably about 25% by weight, of recycled polyester; and In the aforementioned weft thread: 70-99% by weight, preferably about 90% by weight of cotton, 1-20% by weight, preferably about 10% by weight, of recycled polyester The fabrics described in [2], including the following.

[13] According to ISO15797, it is durable for at least 50 washes and has the following characteristics: - Color retention score greater than 2 or 3 based on grayscale comparison of ISO105-A02; - Exceeds the surface ignition criteria of ISO 11612 according to the test procedure of ISO 15025 (2000). - Exceeds the lower edge ignition criterion of ISO 11612 according to the test procedure of ISO 15025 (2000); - Tear strength exceeding 10N according to ISO 13937-2 (2000); - Tensile strength exceeding 300N according to ISO13934-1(2013) A fabric as described in any one of [1] to

[12] , possessing at least one or more of the following.

[14] A fabric according to any one of [1] to

[13] that has wear resistance to more than 15,000 cycles, preferably more than 20,000 cycles by the Martindale method, and satisfies ISO 12947-2 for a force applied at 12 kPa.

[15] The fabric according to any one of [1] to

[14] , wherein the non-cellulose reactive treatment comprises a THP salt, and preferably the amount of phosphorus in the final fabric is less than 2.5% by weight, and / or the amount of nitrogen in the final fabric is less than 2.0% by weight.

[16] A method for producing a flame-retardant fabric comprising a yarn comprising a mixture of natural and / or synthetic fibers and lyocell fibers having reachable hydroxyl groups, the method comprising first subjecting the fabric to a non-cellulose reactive FR treatment, and subsequently finishing the fabric by applying a resin to stabilize the fibrillation of the lyocell.

[17] Preferably the method according to

[16] , comprising weaving the yarn with warp and weft threads in a twill weave to construct the fabric.

[18] The method according to

[17] , wherein the lyocell is present only in the warp threads.

[19] The method according to any one of

[16] to

[18] , wherein the FR treatment is a THP-based process.

[20] The method according to any one of

[16] to

[19] , wherein finishing the fabric by applying a resin comprises crosslinking the resin, preferably a formaldehyde resin.

[21] The method according to any one of

[16] to

[20] , which further comprises a water-repellent and / or oil-repellent treatment, preferably provided in a separate step after the application of the resin to prevent fibrillation.

[22] The method according to any one of

[16] to

[21] , wherein, before subjecting the fabric to the FR treatment, the fabric is pretreated by one or more processes selected from the group consisting of desizing, sculpting, bleaching, mercerizing, and dyeing, including reactive and non-reactive dyes.

[23] The method according to any one of

[16] to

[22] , wherein the yarn is a spun yarn containing a close mix of artificial fibers.

[24] Garments made from any of the fabrics described in any one of the items [1] to

[15] , or made by any of the methods described in any one of the items

[16] to

[23] .

Claims

1. A flame-retardant (FR) fabric comprising yarn formed from a mixture of natural and / or synthetic fibers, wherein the yarn further comprises lyocell fibers, wherein the fabric is subjected to a non-cellulose reactive FR treatment, and the lyocell fibers after the FR treatment are further reduced in fibrilization.

2. The fabric according to claim 1, which is a woven fabric including warp threads and weft threads.

3. The fabric according to claim 1 or claim 2, wherein the natural fiber includes cotton.

4. The fabric according to claim 1 or claim 2, wherein the synthetic fiber comprises polyester, polyamide and / or aramid.

5. The fabric according to claim 2, wherein the lyocell fibers are present only in the warp threads.

6. The fabric according to claim 5, wherein the warp threads include lyocell fibers, synthetic fibers, and natural fibers.

7. The fabric according to claim 5 or claim 6, wherein the weft yarn contains 70% to 95% by weight of natural fibers.

8. The fabric according to claim 2, which is woven as a twill weave.

9. The fabric according to claim 1 or claim 2, wherein the lyocell fibers after the FR treatment are reduced in fibrillation by an anti-fibrillation finish including the application of an anti-fibrillation additive.

10. The fabric according to claim 1 or claim 2, further comprising a water-repellent and / or oil-repellent finish.

11. The fabric according to claim 1 or claim 2, further comprising antistatic fibers.

12. In the aforementioned warp threads: 40-60% by weight of lyocell, 15-35% by weight of cotton; and 15-35% by weight of recycled polyester; and In the aforementioned weft thread: 70-99% cotton by weight, 1-20% by weight of recycled polyester The fabric according to claim 2, including the following.

13. It is durable for at least 50 washes according to ISO 15797 and has the following characteristics: - Color retention score greater than 2 or 3 based on grayscale comparison of ISO 105-A02; - Exceeds the surface ignition criteria of ISO 11612 according to the test procedure of ISO 15025 (2000). - Exceeds the lower edge ignition criterion of ISO 11612 according to the test procedure of ISO 15025 (2000); - Tear strength exceeding 10 N according to ISO 13937-2 (2000); - Tensile strength exceeding 300 N according to ISO 13934-1 (2013) The fabric according to claim 1 or claim 2, which holds at least one or more of the following.

14. The fabric according to claim 1 or claim 2, having abrasion resistance to more than 15,000 cycles by the Martindale method and satisfying ISO 12947-2 for an applied force of 12 kPa.

15. The fabric according to claim 1 or claim 2, wherein the non-cellulose reactive treatment comprises a THP salt.

16. A method for producing a flame-retardant fabric comprising yarn containing a mixture of natural and / or synthetic fibers and lyocell fibers, comprising first subjecting the fabric to a non-cellulose reactive FR treatment, and subsequently finishing the fabric by applying a resin to stabilize the fibrillation of the lyocell.

17. The method according to claim 16, comprising constructing the fabric by weaving the threads with warp and weft threads.

18. The method according to claim 17, wherein the lyocell is present only in the warp threads.

19. The method according to claim 16 or claim 17, wherein the FR treatment is a THP-based process.

20. The method according to claim 16 or claim 17, wherein finishing the fabric by applying a resin includes crosslinking the resin.

21. The method according to claim 16 or claim 17, wherein the finishing further includes a water-repellent and / or oil-repellent treatment.

22. The method according to claim 16 or claim 17, wherein, before subjecting the fabric to the FR treatment, the fabric is pre-treated by one or more processes selected from the group consisting of desizing, sculpting, bleaching, mercerizing, and dyeing including reactive and non-reactive dyes.

23. The method according to claim 16 or claim 17, wherein the yarn is a spun yarn containing a close mix of artificial fibers.

24. A garment made from the fabric described in claim 1 or claim 2.

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