Flame retardant fabrics containing cotton alternatives

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] HEAT AND FLAME RETARDANT FABRIC AND METHODS FOR MAKING SAME FIELD OF THE DISCLOSURE The fabric comprises a cellulose-based cotton substitute that has heat and flame retardant properties. [Background technology]

[0002] Many professions require individuals to be exposed to the risk of exposure to extreme heat and / or flame. Typical examples are industrial workers, firefighters, police and military personnel. Such personnel are provided with suitable flame protective clothing whenever possible. These garments are distinct from normal everyday wear clothing because they are at least partially constructed from flame retardant fabrics.

[0003] The garment must pass minimum thermal performance requirements, such as flame and / or heat retardancy, resistance to molten metals, electrical arc resistance, low rate of (presumptive) body burns in thermal manikin tests, limited afterflame time, high resilience to combustion, and protection against radiant heat.

[0004] In addition to specialized fire protective clothing, more general workwear often requires high flame resistance, which may be certified by one or more standards. Other important performance requirements are tensile and tear strength, elongation at break, abrasion resistance, snagging resistance, and resistance to penetration by water and liquid chemicals.

[0005] Additionally, it is believed to be important that the garment achieves adequate comfort, for example, by allowing vapor to be transported away from the body and ensuring that the garment is not too stiff. The garment must also be durable in the sense that the parameters disclosed above will continue for at least the intended or guaranteed life of the product, which may be defined by a number of wash cycles.

[0006] Additionally, the garments must be printable or dyeable with durable results, for example so that they can be dyed to increase visibility. An often used standard for performance requirements for heat and flame retardant clothing made from flexible materials is ISO 11612.

[0007] A well-known treatment for rendering cellulosic fibers or fabric articles containing cellulosic fibers flame retardant is the Proban® treatment, which involves padding the fabric article with an aqueous solution containing tetrakishydroxyalkylphosphonium (THP) salts that have been pre-reacted with urea and adjusted to a pH between 5 and 8.

[0008] THP does not substantially react with cellulose fibers or with fabric articles containing said fibers, but instead forms a coating network around and / or throughout the molecular structure of the cellulose fibers. Thus, the Proban treatment is a non-cellulose reactive treatment, meaning that there is substantially no chemical reaction between THP and the cellulose fibers. Alternative non-cellulose reactive treatments to Proban and THP may achieve the same effect.

[0009] An alternative flame retardant treatment is a treatment with N-methylol phosphonate compounds, such as N-methylol dialkyl phosphonopropionamide. Commercially, such treatments are offered under the brands Pyrovatex® CP and Aflammit® KWB. In this case, the flame retardant compound is grafted onto cellulose by reaction on the C(6) hydroxyl group of cellulose, resulting in a grafted protected phosphonopropionamide molecule on the outside of the cellulose fiber. Therefore, this is an example of a cellulose-reactive phosphorus-containing compound, since there is a reaction between cellulose and phosphorus-containing compounds. Therefore, Pyrovatex treatment has a fundamentally different chemistry and mechanism from the Proban process.

[0010] Pyrovatex and Proban were developed to make cotton flame retardant, but have many associated problems with the resulting fabric. US Patent Publication No. 3,816,068 A1 discloses a flame retardant for cellulosic fabrics and describes the disadvantages of the Pyrovatex process. The disadvantages of Pyrovatex-treated fabrics include its incompatibility with many other treatments and its 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 unpleasant odors associated therewith. Typically, the degree of flame retardancy achieved is more limited than THP treatment, and the process is only compatible with up to 20% synthetic fibers. EP Patent Publication No. 0,709,518 A1 discloses Proban-treated cotton fabrics. This document is directed to solving the stiffness problem of 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 referred to as 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. In the following, 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 choice of environmentally friendly options. Although natural fibers, such as cotton, may be more advantageous than synthetic fibers in some respects, it is well known that cotton is of relatively high impact in terms of the requirements for its production, especially in terms of water usage. It is desirable to provide cotton substitutes that 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 disadvantages of the viscose process. It also has a significantly lower water footprint than cotton, using up to 95% less water. However, until now it has not been possible to adequately replace cotton with Lyocell where flame retardancy is required in combination with durability and other workwear requirements. In particular, Lyocell's tendency to fibrillate has been seen as a major drawback. Summary of the Invention [Problem to be solved by the invention]

[0014] It would be desirable to provide an alternative to regular FR cotton that has a smaller environmental footprint, yet still meets at least certain quality requirements expected of protective clothing. [Means for solving the problem]

[0015] According to the present invention, a flame retardant (FR) treated fabric is provided, comprising yarns 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 less fibrillated. In the following, the term "lyocell" is used to indicate an artificial cellulose-based cotton substitute. In particular, these may represent cellulose fibers obtained by an organic solvent spinning process, but the present invention may also be applicable to some cellulose fibers that can be obtained by a viscose process. Lyocell, for example the Tencel® products available from Lenzing AG, is well known, but other similar cellulose-based cotton substitutes are available and may be equally applicable. Lyocell may be present in the form of short man-made fibers, long man-made fibers, or as filaments or ribbons. Furthermore, in this context, reference to natural and synthetic fibers is intended to exclude lyocell fibers, i.e., these are lyocell and others. Any amount of lyocell may be present, depending on the properties required. In particular, there may be 1-99% by weight of lyocell, preferably 10-70% by weight, more preferably 15-50% by weight of lyocell or 20-35% by weight of lyocell.

[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 in a wet fabric state. As a result of research, it has also been revealed that in the context of the present invention, fibrillation is further exacerbated 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 at the fiber surface. The rate of fibrillation increases with increasing pH and increasing temperature, as experienced during normal FR treatment. Unlike cotton, lyocell does not naturally crosslink, and therefore it is desirable to provide a finish that at least partially compensates for the increased fibrillation. For lyocell-like materials, it is believed that the fibrils are held together at least in part by hydrogen bonds between adjacent fibrils. For example, in the presence of water or as a result of certain treatments, a reduction in the degree of hydrogen bonding can result in increased fibrillation.

[0017] Anti-fibrillation finishes can be performed on fabrics by application of suitable additives. Preferably, the additives are substances that react with the hydroxyl groups of cellulose to stabilize the fibrils. This can be by increasing the presence of hydrogen bonds or by forming covalent bonds, whereby improved cross-linking of the fibrils is achieved. Additives that cross-link by forming covalent bonds to the hydroxyl groups of cellulosic materials can 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 the preferred choice. Those skilled in the art are 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 cross-links to the hydroxyl groups of lyocell. Alternatively, it can be determined experimentally, for example by pilling, abrasion, color retention or other tests as specified below.

[0018] In one embodiment, the natural fiber comprises FR cotton. The fabric may have the overall feel of a cotton fabric, with some of the cotton being replaced with a lyocell substitute. Approximately up to 50% of the cotton may be replaced without significantly affecting the overall performance of the fabric. Nevertheless, the softness of the fabric increases significantly and is generally experienced as very comfortable during use. However, in general, when cotton is replaced with lyocell, a certain amount of stronger fibers may be required, such as synthetic fibers to offset the loss of certain properties or to otherwise complement the lyocell. In particular, lyocell generally has a slightly lower wet strength than cotton, but the strength is significantly reduced after THP processing. Therefore, polyester may be added to the fiber blend to compensate. However, it is not excluded that other natural fibers, such as linen or wool, may be present in greater or lesser amounts.

[0019] In one embodiment, the synthetic fibers include polyester. Other synthetic fibers, such as polyamide or aramid, may also be contemplated, and it is not excluded that they may include additional low-volume high-performance synthetic fibers. In one embodiment, the synthetic fibers include recycled polyester. One preferred source of recycled polyester is Repreve® from Unifi Inc, which is a mechanically regenerated polyester. Chemically regenerated polyester may also be used. Regenerated 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 greater than 30% reduction in greenhouse gas emissions compared to virgin polyester. Regenerated polyester has excellent strength properties and adds durability, but it does not respond to many FR treatments. Synthetic fibers can exist in various forms, including short man-made fibers, long man-made fibers, and filaments.

[0020] It is understood that various possible fabrics can be envisioned, including woven and knitted fabrics. Woven fabrics are preferred. Woven fabrics can have any suitable configuration, formed from warp and weft threads in a selected weave or pattern. The threads, both warp and weft, can all be the same or can be different, with respect to their composition, weight, etc. Each thread can be a spun yarn. It is understood that a spun yarn comprises an intimate blend of constituent fibers. Some ends of the yarns can be twisted together to form a ply. A ply can also be formed by twisting spun fibers having one or more filaments.

[0021] In one embodiment, lyocell fibers may be present only in the warp yarns. This has been found to be most suitable for cases where the lyocell has been adequately stabilized against fibrillation by a finishing process. In that case, the lyocell may be reinforced by the presence of synthetic fibers that are also blended in the warp yarns. If the lyocell is subject to fibrillation, it may be preferable to include the lyocell instead only in the weft yarns, for example to reduce its exposure to the outer surface of the fabric in a twill weave.

[0022] In a particular embodiment, the warp yarns include lyocell fibers, synthetic fibers, and natural fibers. Thus, the blend can be of lyocell, cotton, and polyester man-made fibers, which together make up at least 95% of the warp yarns. In one embodiment, 50% of the warp yarns can include lyocell, with equal amounts of cotton and polyester making up the remainder. In one embodiment, they can be present in the warp yarns in a weight percent ratio of approximately 50 / 25 / 25, respectively.

[0023] It has been observed that there are certain relationships between the different characteristics of the fabric that result in optimized results. In particular, it can be noted that an increase in the use of lyocell requires a commensurate increase in the amount of stronger synthetic fibers needed to compensate for the loss of strength of the lyocell (especially after being subjected to FR treatment). Corresponding to the increased lyocell, the synthetic fibers are present in the yarn direction. In the case of synthetic fibers that are neither inherently FR nor FR treatable, the total amount of synthetic fibers that can be introduced depends on the degree of FR treatment of the natural fibers and the lyocell. For reasons that will be explained further below, a limited degree of FR treatment may be preferred to avoid excessive fibrillation. Thus, the overall amount of non-FR synthetic fibers that can be present in the mix may be limited. For this reason, the above 50 / 25 / 25 mix in the warp yarns has been found to be rather suitable, with obvious variations thereof achieving the same advantageous effects.

[0024] However, when synthetic fibers are introduced in one direction, the fabric may be unstable, for example, in terms of shrinkage. For this reason, a limited amount of synthetic fibers may be required in the other weave direction, for example, a 90 / 10 cotton / polyester blend may be appropriate. An overall blend of approximately 50 / 30 / 20 cotton / lyocell / polyester may result. It is noted that, in general, a low amount of synthetic fibers may be preferred, since its main purpose is strength reinforcement and synthetic fibers have a negative impact on the overall fabric FR level. Nevertheless, an amount of synthetic fibers that exceeds that achievable for Pyrovatex type processing 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. Alternative fiber percentages that remain below the upper limit for compatibility with THP FR processing may be selected depending on the end use and are within the scope of this application. For example, providing softness, color retention percentages, or containing a higher amount of earth-friendly fibers that provide desirable strength.

[0026] In one embodiment, the weft yarns may comprise a predominance of natural fibers, preferably between 70% and 95% by weight of natural fibers, especially cotton.

[0027] Any suitable weave configuration may be contemplated, and those skilled in the art are well aware of the advantages of each of such weaves. In one embodiment, the fabric may be woven as a twill weave, preferably a 2 / 1 twill weave. Satin weaves may also be used where it is desirable to achieve a particular drape or ensure that certain yarns are exclusively provided on one side or the other. The fabric may also be a double cloth, a two-sided fabric, or a fabric with two identical sides, with separate properties on each face and back.

[0028] According to an important aspect of the present invention, the fabric includes an anti-fibrillation finish to prevent lyocell from fibrillating. As mentioned above, lyocell does not naturally crosslink, and therefore it is desirable to provide a finish that at least partially compensates for increased fibrillation. Importantly, while the use of finished lyocell fibers is well known in preventing fibrillation, it has now been found that non-fibrillating finishes are detrimental to the application of flame retardant treatments to lyocell fibers. By using untreated lyocell fibers, i.e., lyocell fibers that have not been subjected to an anti-fibrillation treatment, improved application of FR treatments can be achieved. This has been found to be particularly true for Proban type (THP) treatments. Without being bound by theory, it is believed that the presence of crosslinked resins, such as formaldehyde, prevents 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, an anti-fibrillation resin finish may be applied following the FR treatment. However, it has also been found that the FR treatment itself may have a subsequent negative effect on the anti-fibrillation finishing process. This is believed 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 may be kept below 2.5 wt%, preferably below 2.4 wt% or even below 2.2 wt%. The values ​​for nitrogen also reflect the degree of FR treatment, which may be kept below 1.7 wt% or below 1.6 wt% or even below 1.5 wt%. These values ​​have also been found to ensure proper FR compliance. Nevertheless, as mentioned above, the reduction in the degree of FR treatment limits the overall content of synthetic fibers that may be present in the blend in case 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 alkylating substances) finishes, such as PTFE, Teflon®, etc. Alternatively, the fabric of the present disclosure can also be made with a PFAS-free finish, thus being more environmentally friendly.

[0031] As mentioned above, the fabric may also contain other fibers or yarns for specific technical purposes. For protective workwear, antistatic fibers may be included as fibers in the blend or as separate antistatic yarns or filaments. In one embodiment, the fabric may contain antistatic fibers or filaments in an amount of 0.2% to 3% by weight. If antistatic man-made filaments are used, as much as 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 has in the warp yarns: 40-60% by weight, preferably approximately 50% by weight, of lyocell, 15-35% by weight, preferably approximately 25% by weight, of cotton; and 15 to 35% by weight, preferably approximately 25% by weight, of recycled polyester; and In the weft: 70 to 99% by weight, preferably approximately 90% by weight, of cotton; 1 to 20% by weight, preferably about 10% by weight, of recycled polyester may include.

[0033] The fabric desirably will withstand at least 50 washings per ISO 15797 without losing its required properties. These may include one or more of the following: Color retention score of >2 or >3 according to ISO105-A02 grayscale comparison; · Exceeds ISO 11612 surface ignition criteria according to ISO 15025 (2000) test procedures; Exceeds ISO 11612 lower edge ignition criteria per ISO 15025 (2000) test procedure; Tear strength >10N according to ISO13937-2(2000); Tensile strength of over 300N according to ISO13934-1(2013). The fabric should also preferably exhibit fabric abrasion resistance to greater than 15,000 cycles, preferably greater than 20,000 cycles by the Martindale method and 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 THP salts, for example the Proban® treatment.

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

[0036] In this context, the term "accessible 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 the FR treatment can reduce the effectiveness of the treatment. For this reason, it is desirable to carry out the FR treatment on a fabric in which the lyocell fibers provided in the yarn have not yet been stabilized against fibrillation by treatments that can occupy hydroxyl groups.

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

[0038] The fabric may be any suitable fabric, including a woven or knitted fabric, and the method may include 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 being applied to the yarns themselves. Constructing the fabric may preferably include weaving the yarns in a warp and weft in a twill weave. In one embodiment, the lyocell is present in the yarns only in the warp direction.

[0039] Finishing the fabric by application of resin may involve the use of any suitable chemical reaction to prevent fibrillation. Preferably, the resin is a material that reacts with the hydroxyl groups of the cellulose to stabilize the fibrils. Such resins may be referred to as 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 the preferred choice, but equivalents and alternatives may equally be applied. The finishing step may be completed by crosslinking the resin, for example by application of heat.

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

[0041] The present invention also relates to a garment made by a method as hereinbefore or hereinafter described.

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

[0043] Some materials are particularly attractive for consideration in environmentally friendly products: recycled materials, sustainable materials, and materials with low water scarcity have less of an environmental impact.

[0044] Flame retardant (FR) is defined in this application to mean flame and / or heat retardant properties imparted by a treatment to a filament, fiber, yarn or fabric, which may provide fabrics with low rates of (presumptive) body burns in thermal mannequin tests, limited afterflame time, high resilience to burning, and protection against radiant heat, electrical arcs and molten metals, e.g., meeting the performance requirements for flame retardant clothing made from flexible materials of ISO 11612. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0046] An exemplary manufacturing process steps are described as follows: · First, man-made fibres are formed into yarn by spinning. These yarns are then woven into unbleached and undyed fabric as per desired and optimum specifications. · Check unbleached and undyed fabrics. · Perform pre-treatment including desizing, scouring and bleaching. In a further pre-processing step, cotton and lyocell are mercerized. The fabric is then dyed in a continuous dyeing process including dyeing and fixing. The fabric is then checked for color defects and then put into the finishing process line. · One or two FR processing steps can be performed involving impregnation of the fabric and ammonia curing. The fabric is mechanically softened in an air tumbler, making it more flexible. The product is spread on a tenter frame and treated with resin to prevent fibrillation. The fabric is subsequently heat treated to crosslink the added resin. Apply a further finish to achieve oil and water repellency. Heat treat / cool the product. Sanforize the fabric to reduce shrinkage. Next, quality control is carried out. This is followed by packaging and shipping to a clothing manufacturer, who fashions it for a specific use, e.g. a specific workplace uniform.

[0047] Man-made fibers that are formed into yarns 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. There are other alternative cellulose-based cotton substitutes, 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. It has practically the same strength as cotton when wet and is more durable than cotton. Compared to cotton, Lyocell uses 95% less water than cotton. Lyocell is more comfortable than cotton with better moisture management and is generally smoother on the skin. However, it is a fiber that fibrillates. For example, when wet, water penetrates inside the fibril bundles, resulting in the exposure of the fibrils at the fiber surface. The rate of fibrillation increases with increasing pH and increasing temperature.

[0049] (Regenerated) polyester can be mechanically or chemically regenerated. Polyester is used in FR treated fabrics, which increases durability because it is a relatively stronger material, but is also heavier than cellulose-based fabrics. Polyester cannot be made flame retardant with Proban chemistry. Mechanically regenerated polyester can be used to improve sustainability. The use of recycled polyester achieves a 45% reduction in energy consumption compared to the use of virgin polyester, and has an approximately 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, yarn was spun using the following man-made fibers: Cotton (medium quality) Count: 3.8~4.4Micronair Length: 27mm Tenacity: 26~30cN / tex Tencel Lyocell Standard Count: 1.25dtex Length: 38mm Tenacity: 38cN / tex Tenacity, damp, 31cN / tex Repreve recycled polyester Count, 1.3dtex Length: 38mm Tenacity: 59cN / tex Nega-Stat® P190 Count: 39 / 6 dtex Length = filament

[0051] An exemplary formulation of the textile yarn is as follows: Warp: 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] The EC9600 fabric is woven in a 2 / 1 twill weave with the warp and weft yarns described above. Antistatic yarns are spaced 1:20 apart in the weft direction. The overall weight percentage of each fiber in the final fabric is: 50% cotton; 30% Lyocell; 19% recycled polyester, 1% Negastat filament It is.

[0053] After single pass THP treatment, the fabrics were determined to have the following flame retardant intrinsic values:

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

[0055] The fabric after FR treatment is still vulnerable to fibrillation. Finishing the fabric after FR treatment with a suitable resin prevents fibrillation of the lyocell in the product. The resin is applied in a foulard process, which includes removing water by pressing and heating, followed by heat treatment to crosslink the resin. The term non-fibrillation, as used herein, is understood to mean substantially non-fibrillation and is interchangeable with low fibrillation. The application of a non-fibrillating resin achieves a fabric with reduced fibrillation compared to the fabric in its untreated state.

[0056] A second finish is required to make the fabric water and / or oil repellent with fluorocarbon resin (FC) to meet ISO 13034. The resin and FC may be combined in one batch, or the resin and FC finishes may be applied one after the other 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 first crosslink the resin before applying the FC finish.

[0057] Washing according to standard ISO 15797, 75°C, j criteria is possible, resulting in reduced and uniform fibrillation. The fabric remains durable up to 50 rigorous washes according to ISO 15797, 75°C, j.

[0058] The final product has the following advantages: 50% eco-friendly materials, -Durable and long-lasting, 28% lower water footprint than traditional FR treated fabrics; 10% lower CO2 footprint than traditional FR treated fabrics; Very soft and breathable thanks to the lyocell Low water vapor resistance (breathability) and good short-term vapor absorption, Better performance than traditional FR treated fabrics, Traditional FR treated cotton fabric feels stiff and sturdy, while EG9600 feels supple and soft against the skin. -FR performance equal to that of traditional FR treated cotton fabrics; -Low pilling. EXAMPLES

[0059] Three batches of the improved FR fabric were tested and the properties measured after finishing were shown to be reproducible and in accordance with the technical specifications with the following details:

[0060] [Table 1]

[0061] The technical specifications of the fabrics of the present invention are comparable and commensurate with standard FR fabrics and an alternative inherently flame retardant fabric known as Modal / Tencel™ in terms of properties. The improved FR fabrics of the present invention further have improved comfort and a reduced carbon footprint. A comparison of the technical specifications is as follows:

[0062] [Table 2]

Claims

1. A flame-retardant (FR)-treated fabric, comprising yarns formed from a mixture of natural and / or synthetic fibers, and further comprising FR-treated lyocell fibers, wherein the FR treatment is a non-cellulosic reactive FR treatment, and the FR-treated lyocell fibers have low fibrillation.

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

3. The fabric according to claim 1 or claim 2, wherein the natural fiber comprises 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 yarns.

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

7. The fabric according to claim 5 or claim 6, wherein the weft yarns predominantly comprise 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, further comprising an anti-fibrillation finish comprising 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 warp yarns: 40 to 60% by weight of lyocell, 15 to 35% by weight of cotton; and 15 to 35% by weight of recycled polyester; and In the weft yarns: 70 to 99% by weight of cotton, 1 to 20% by weight of recycled polyester The fabric according to claim 2, comprising.

13. Durable against at least 50 launderings according to ISO 15797, having the following properties: - A color retention score of more than 2 or more than 3 by gray scale comparison of ISO 105-A02; - Exceeding the ignition criterion on the surface of ISO 11612 according to the test procedure of ISO 15025 (2000); - Exceeding the ignition criterion at the lower edge part of ISO 11612 according to the test procedure of ISO 15025 (2000); - A tear strength of more than 10 N according to ISO 13937-2 (2000); - A tensile strength of more than 300 N according to ISO 13934-1 (2013) The fabric according to claim 1 or claim 2, retaining at least one or more of.

14. The fabric according to claim 1 or claim 2, having abrasion resistance for 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-cellulosic reactive treatment contains a THP salt.

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

17. The method according to claim 16, comprising constructing the fabric by weaving the yarn 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 application of a resin comprises crosslinking the resin.

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

22. Before subjecting the fabric to the FR treatment, the fabric is pretreated by one or more processes selected from the group consisting of desizing, singeing, bleaching, silk finishing, and dyeing including reactive and non-reactive dyes. The method according to claim 16 or claim 17.

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

24. Clothing manufactured from the fabric according to claim 1 or claim 2, or manufactured by the method according to claim 16 or claim 17.