KR20170067845A - High Tenacity or High Load Bearing Nylon Fibers and Yarns and Fabrics Thereof - Google Patents

Abstract

High strength or load-bearing nylon fibers and yarns, fabrics and articles of manufacture thereof and methods of making them are provided having a tenacity of greater than 7.5 g / den and / or a tenacity at 10% elongation greater than 4.0 g / den.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to high tenacity or high load bearing nylon fibers and yarns and fabrics thereof,

The present disclosure relates to the production of improved nylon staple fibers, preferably having high strength, as measured by breaking strength and tenacity at 7% and 10% elongation. Such nylon staple fibers can be produced by preparing tows of relatively uniformly radially and rapidly quenched nylon filaments, stretching and annealing the tows in the presence of steam, then cutting the drawn and annealed tows into desired high strength nylon staple fibers Or otherwise. The nylon staple fibers so produced can also be blended with other fibers, such as cotton staple fibers, to produce yarns that preferably also have high strength. Next, such yarns are advantageously lightweight, comfortable, inexpensive, and durable, so that they are particularly suitable for use in, or as applications in, military apparel, such as combat uniforms, Fabrics and other articles of manufacture.

The present disclosure also relates to high strength Indian nylon fibers and nonwoven composites of cellulose based or regenerated synthetic or natural fiber technology. End uses for the composite include, but are not limited to, industrial (felt / backing / filtration / insulation), clothing (including viscous), shoes, back / pack hard gear, durable and semi-durable (disposable or semi-disposable) Clothing or PPE, such as FR (chemically treated or combined with native FR fiber technology), biochemical products, or other special protective clothing.

Nylon has been manufactured and used on the market for a long time. The first nylon fibers are nylon 6,6 poly (hexamethylene adipamide), while nylon 6,6 fibers are still manufactured and used as major nylon fibers in the market. Nylon 6 fibers produced from a large amount of other nylon fibers, in particular caprolactam, are also produced and used in the market. Nylon fibers are used in woven and other yarns. For textile, there are essentially two major yarn categories: continuous filament yarns and yarns made from staple fibers, i.e., cut fibers.

Nylon staple fibers are typically prepared by melt-spinning a nylon polymer into filaments, collecting a very large number of such filaments in a tow, applying the tow to a stretching operation, and then converting the tow to staple fibers, Has come. The tow typically contains thousands of filaments, and generally has a total denier of the order of hundreds of thousands (or more). The stretching operation involves increasing the orientation of the filament nylon polymer by transferring the tow between a series of feed rollers and a series of stretching rollers (which is operated at a higher speed than the feed rollers). In order to increase the nylon crystallinity in the tow filaments before the tow is converted to staple fibers, the stretching is often combined with the annealing operation.

One of the advantages of nylon staple fibers is that they are easily blended with natural fibers, such as cotton (often referred to as short staples), and / or other synthetic fibers, thereby achieving the benefits deriving from the blending . Particularly preferred types of nylon staple fibers have been used for blending with cotton for many years, in particular to improve the durability and economy of fabrics made from yarns comprising a blend of nylon and cotton. No. 3,044,250 to Hebeler, the disclosure of which is incorporated herein by reference in its entirety; 3,188,790; 3,321,448; And 3,459,845, because such nylon staple fibers have a relatively high load-bearing tenacity. As described by Heberger, the load-bearing capacity of nylon staple fibers is typically measured as the tenacity (T ₇ ) at 7% elongation, the T ₇ parameter has been accepted as a standard measurement for a long time, ) Is easily decoded in the device.

The Hebler process for making nylon staple fibers includes the nylon spinning, tow forming, stretching and converting operations described above. Thereafter, an improvement in the Hebler process for making nylon staple fibers, by modifying the properties of the tow elongation operation, and by adding certain types of annealing (or hot treatment) steps and subsequent cooling steps to the overall process . For example, in US Pat. Nos. 5,093,195 and 5,011,645, Thompson discloses a method of spinning a nylon 6,6 polymer having a formic acid relative viscosity (RV) of, for example, 55, to a filament and then stretching it, annealing, And then cut into staple fibers having a toughness T at break of about 6.8 to 6.9, a denier per filament of about 2.44, and a load-bearing capacity T ₇ of about 2.4 to 3.2. The Thompson patent also discloses that such nylon staple fibers are blended with cotton to form yarns having improved yarn strength (all of the Thompson patents are incorporated herein by reference in their entirety).

The nylon staple fibers made according to Thompson technique were blended with NYCO yarns (typically 50:50 nylon / cotton ratio) and the yarns were used to make NYCO fabrics. The NYCO fabrics, such as woven fabrics, are applied to military combat uniforms and garments. Although such fabrics have generally proved satisfactory for military or other harsh garment applications, for example, the military authorities are less lighter in weight, lower in cost, and / or more comfortable, yet still highly durable, Continues to seek improved fabrics that can have improved durability.

The present invention relates to the manufacture of nylon staple fibers having extreme high strength yarns (both toughness and low elongation toughness). The present invention makes it possible to apply a higher draw ratio to the currently applied normal draw ratio by applying steam. The product is then annealed and dried under tension. Annealing / oven drying under tension to help remove excess moisture generated during the steam draw process. The obtained fiber fracture toughness increases from 7.1 grams / den average to 7.5-7.75 grams / denier range. The tenacity at 10% elongation is also increased by 10-20% relative to the standard product or the modified product. Fabrics made from such fibers have higher strength or equivalent strength in terms of grab and tear strength, but at a maximum of 1.0 oz. It is expected to be more lightweight.

Accordingly, embodiments of the present invention are directed to high strength or load bearing nylon staple fibers having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / den at 10% elongation.

Another aspect of the present invention relates to yarn, at least a portion of which is a high strength or load-bearing nylon staple having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / It is emitted from fiber.

In one embodiment, the yarns are made by blending these nylon staple fibers with at least one accompanying staple fiber.

In one embodiment, the yarn can be a nylon / cotton (NYCO) yarn and is then durable, optionally lightweight, woven with NYCO fabrics, which is particularly suitable for military or other harsh applications.

Another aspect of the invention relates to lightweight fabrics that meet or exceed the current military fabric strength and tear specifications established for fabrics weighing> 6.0 oz./yd ² and less than .0 oz./yd ² . The fabric is made from a fiber blend, at least a portion of which includes high strength or load bearing nylon staple fibers having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / den at 10% elongation.

Another aspect of the invention relates to articles of manufacture, and at least some of which are high strength or load bearing nylon staples having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / Fiber.

Another aspect of the invention is directed to a nonwoven composite comprising high strength Indian fibers and cellulose based or recycled synthetic or natural fibers.

In one embodiment, the high strength Indian fibers used in the nonwoven composite are selected from high strength or load-bearing nylon staple fibers having a breaking strength of greater than 7.5 g / den and / or a tenacity at 10% elongation of greater than 4.0 g / .

Another aspect of the invention relates to a method of making high strength or load bearing nylon staple fibers having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / den at 10% elongation. The method comprises melt-spinning the nylon polymer into filaments, uniformly quenching the filaments and forming tows from a plurality of these quenched filaments, stretching the tow in the presence of steam, annealing under tension, stretching and annealing the resulting tow, For example, converting into staple fibers suitable for forming spinning yarns.

According to the present disclosure, high strength or load-bearing nylon staple fibers, yarns, fabrics and other articles of manufacture having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / A method is provided, at least a portion of which is made from these fibers.

The present disclosure also provides a nonwoven fabric composite comprising high strength Indian fibers and cellulose based or regenerated synthetic or natural fibers.

As used herein, the terms "durable" and "durability" refer to materials that have moderately high grab and tear strength as well as resistance to abrasion in the intended end use of the fabric, Refers to the tendency of the fabric to be characterized by maintaining such durability characteristics for a length of time.

As used herein, the term blend or blended when referring to a spinning yarn means a mixture of two or more types of fibers wherein the individual fibers of each fiber type are substantially completely Are formed in such a way as to provide a substantially homogeneous fiber mixture with sufficient entanglement to maintain its integrity during further processing and use.

As used herein, a cotton count refers to a yarn numbering system based on a length of 840 yards, where the yarn count is the number of 840-yard yarns required to weigh one pound, .

It is understood that all numerical values referred to herein are to be modified by the term "about ".

Certain embodiments are based on the production of improved nylon staple fibers having certain specific properties and subsequent fabrication of the yarns and fabrics woven from such yarns wherein the improved nylon staple fibers comprise one or more Blended with other fibers. The other fibers include cellulosics such as cotton, modified cellulose-based products such as FR-treated cellulose, polyester, rayon, animal fibers such as wool, salt tolerant (FR) polyester, FR nylon, FR rayon, FR- - aramid, p-aramid, modacrylic, novoloid, melamine, polyvinyl chloride, antistatic fibers, PBO (1,4-benzene dicarboxylic acid, 4,6- A polymer with 3-benzene diol dihydrochloride), PBI (polybenzimidazole), and combinations thereof. The nylon staple fibers of some embodiments can provide increased strength and / or abrasion resistance to yarns and fabrics. This is especially true in combination with relatively weaker fibers such as cotton and wool.

Specific properties of the nylon staple fibers produced and used herein include fiber denier, fiber toughness, and fiber load-bearing capacity as defined in terms of fiber strength at 7% and 10% elongation.

The implementation of the desired nylon staple fiber material of the present application is also based on the use of nylon polymer filament staple fiber fabrics and tows having certain selected properties and being processed using certain selected processing operations and conditions. ++

The nylon polymer itself used in the spinning of the nylon filaments of the present invention can be prepared in a conventional manner. The nylon polymers suitable for use in the methods and filaments of some embodiments are composed of synthetic melt spinnable or melt spinning polymers. Such nylon polymers may include polyamide homopolymers, copolymers, and mixtures thereof, which are predominantly aliphatic, i.e., less than 85% of the polymer amide-bonds are attached to two aromatic rings. Polyamide polymers widely used such as nylon 6,6 poly (hexamethylene adipamide) and nylon 6 poly (epsilon-caproamide), and copolymers and blends thereof can be used according to certain embodiments. Other polyamide polymers that may be advantageously used include nylon 12, nylon 4,6, nylon 6,10, nylon 6,12, nylon 12,12, and copolymers and mixtures thereof. Exemplary polyamides and copolyamides that may be used in some embodiments of the methods, fibers, yarns, and fabrics are described in U.S. Pat. Those described in U.S. Patent Nos. 5,077,124, 5,106,946, and 5,139,729 (all of Cofer et al.) And in Gutmann in Chemical Fibers International, pages 418-420, Volume 46, December 1996 ≪ / RTI > All of these publications are incorporated herein by reference.

The nylon polymers used in the manufacture of nylon staple fibers typically comprise at least one of the appropriate monomers, catalysts, antioxidants and other additives such as plasticizers, delusters, pigments, dyes, light stabilizers, heat stabilizers, An antistatic agent, an additive for modifying the dye performance, a preparation for modifying the surface tension, and the like. The polymerization has conventionally been carried out in a continuous polymerization apparatus or a batch autoclave. Next, the molten polymer thereby produced is usually introduced into a spin pack, where it is forcibly passed through a suitable spinneret, formed into filaments and quenched, and then subjected to final processing with nylon staple fibers . As used herein, a spinning pack consists of a pack lid at the top of the pack, a spinneret plate at the bottom of the pack, and a polymeric filter holder sandwiched between the two components of the electron. The filter holder is provided with a center concave portion therein. The lid and the recesses of the filter holder together form an encapsulation pocket in which a polymeric filter medium such as sand is received. A channel is provided in the interior of the pack to enable the flow of molten polymer supplied by the pump or extruder to travel through the pack and ultimately through the spinneret plate. The spinneret plate is provided with a series of small, precise holes extending therethrough to transmit the polymer to the bottom surface of the pack. The outlet of the orifice forms a series of orifices at the bottom surface of the spinneret plate whose surface forms the top of the quench zone. The polymer exiting this orifice is in the form of filaments, which in turn pass through the quench zone downstream.

The extent of polymerization carried out in a continuous polymerization apparatus or batch autoclave can generally be quantified by a parameter known as the relative viscosity or RV. RV is the ratio of the viscosity of the nylon polymer solution in the formic acid solvent to the viscosity of the formic acid solvent itself. RV is regarded as an indirect indicator of the molecular weight of the nylon polymer. For the purposes of this application, increasing the nylon polymer RV is considered synonymous with increasing the molecular weight of the nylon polymer.

As the nylon molecular weight increases, the processing of the nylon polymer becomes more and more difficult due to the increased viscosity of the nylon polymer. Thus, the continuous polymerization apparatus or batch autoclave is typically operated such that the nylon polymer provides a nylon polymer for final processing into staple fibers having an RV value of about 60 or less.

For some purposes it is known that the supply of nylon polymers having larger molecular weights, i. E., RV values in excess of 70-75 and below 140, or even above 190, may be advantageous. For example, this type of high RV nylon polymer is known to have improved resistance to bending wear and chemical degradation. Thus, such high RV nylon polymers are particularly suitable for spinning with nylon staple fibers which can be advantageously used in the manufacture of papermaking felt. Procedures and apparatus for making high RV nylon polymers and staple fibers therefrom are described in U.S. Pat. 5,236,652; and U.S. Pat. No. 5,236,652 to Schwinn and West. Patent No. 6,235,390; 6,605,694; 6,627,129 and 6,814,939. All of these patents are incorporated herein by reference in their entirety.

According to some embodiments staple fibers made from nylon polymers having RV values that are generally the same as or generally higher than those generally obtained through polymerization in a continuous polymerization apparatus or batch autoclave, When processed according to the stretching and annealing procedures in the presence of spinning, quenching, feeding and steam as described in < RTI ID = 0.0 > . When such nylon staple fibers having enhanced toughness are blended with one or more other fibers such as cotton staple fibers, textile yarns with improved strength and light weight can be realized. Fabrics such as NYCO fabrics woven from such yarns exhibit advantages as described above with respect to durability, optionally lighter weight, improved comfort and / or potentially lower cost.

According to the staple fiber manufacturing method of the present application, the nylon polymer which is melt-spun and quenched into tow-forming filaments through one or more spinning pack spinning apertures is 55 to 100, 46 to 65; 50 to 60; And an RV value ranging from 45 to 100, inclusive. Nylon polymers having such RV characteristics can be prepared using, for example, the melt blending procedure of a polyamide concentrate such as the process disclosed in the '652 patent of the above-mentioned kidder. The kidder discloses certain embodiments wherein the additive incorporated into the polyamide concentrate is a catalyst for the purpose of increasing the formic acid relative viscosity (RV). Higher RV nylon polymers, such as nylons with an RV of 65-100, available for melting and spinning may be provided by the solid phase polymerization (SPP) step where nylon polymer debris or < RTI ID = 0.0 > The granules are conditioned. Such a solid phase polymerization (SPP) procedure is well known and is described in great detail in the aforementioned Schwinn / West's '390,' 694, '129 and' 939 patents.

Nylon polymeric materials having the requisite RV characteristics as specified herein are fed into a spinning pack, for example, through a double screw melting apparatus. In a spinning pack, the nylon polymer is spun into a plurality of filaments by extrusion through one or more spinnerets. For the purposes of this application, the term "filament" is defined as a relatively flexible, visually homogeneous object having a high length ratio to its width transverse to its cross-section perpendicular to its length. The filament cross section may be of any shape, but is typically circular. As used herein, the term "fiber" may be used interchangeably with the term "filament ".

Each individual spinneret point may include 100 to 1950 filaments in an area as small as 9 inches by 7 inches (22.9 cm by 17.8 cm). The spinning pack apparatus may comprise from 1 to 96 points each of which provides a bundle of filaments that ultimately combine into a single tow band for downstream processing with stretching / other tow bands.

After being drained from the spinneret (s) of the spin pack, the molten filaments extruded through each spinneret typically have various quench conditions and arrangements to solidify the molten polymer filaments and make them suitable for towing together Is passed to the quench zone which can be used. Quenching is most typically performed by passing a cooling gas, such as air, over, over, together with, around, and through the filament bundle extruded from each spinneret point in the spinning pack into the quench zone .

One suitable quench arrangement is a cross-flow quench where cooling gas, such as air, is blown into the quench zone in a direction substantially perpendicular to the direction in which the extruded filament is delivered through the quench zone. Among other quench arrangements, U.S.A. Patent No. 3,022,539; 3,070,839; 3,336,634; 5,824,248; 6,090,485, 6,881,047 and 6,926,854, all of which are incorporated herein by reference.

In one embodiment of the present staple fiber manufacturing process, extruded nylon filaments that are ultimately used to form the desired nylon staple fibers are described in U.S. Patent Application Nos. 2011/0177737 and 2011/0177738, Quenched and towed using both positional uniformity and uniformity of quench conditions as disclosed in US Pat.

The quenched yarn filaments can then be combined into one or more tows. Such tows formed from filaments from one or more spinnerets are then applied to a two-step continuous operation in which the tow is stretched and annealed in the presence of steam.

Drawing of the tow is generally performed primarily in the first or first stretching step or zone where the band of tow is passed between a series of feed rollers and a series of stretching rollers (more rapidly actuated) Thereby increasing the orientation. The extent to which the tow is stretched can be quantified by specifying the draw ratio that is the ratio of the higher peripheral speed of the draw roller to the lower peripheral speed of the feed roller. The effective draw ratio is calculated by multiplying the first draw ratio by the second draw ratio.

The first stretching step or zone may include other tow guides and tensioning rollers, such as snubbing pins, as well as feeding and stretching rollers of the aquarium. The stretching roller surface may be made of a metal, such as chromium or ceramics.

It has been found particularly advantageous for the ceramic elongated roller surface to enable the use of relatively higher draw ratios that are specified for use in connection with the present staple fiber manufacturing process. Ceramic rollers not only improve roller life, but also provide a surface that is less prone to winding. (International Fiber Journal, 17, February 2002: " Textile and Bearing Technology for Separator Rolls, Zeitz and el. &Quot;), all of which are incorporated herein by reference, as well as US Patent 4,794,680 Also discloses the use of ceramic rollers to improve roller life and reduce fiber adhesion to the roller surface.

Although the greatest extent of stretching of the present filament tow is made in the initial or first stretching step or zone, some additional stretching of the tow may generally take place in a second or annealing and stretching step or zone as described below . The total elongation to which the filament tow of the present application is applied is determined by specifying the total effective elongation ratio taking into consideration the elongation which takes place in the first initial elongation step or zone and in the second zone or step in which annealing and some additional elongation are simultaneously carried out ≪ / RTI >

In some embodiments, the tow of the nylon filament is applied to a total effective draw ratio of from 2.3 to 5.0, including 3.0 to 4.0. In an embodiment where the tow per filament denier is generally smaller, the total effective draw ratio may range from 3.12 to 3.40. In another embodiment, where the denier per filament of the tow is generally greater, the total effective draw ratio can range from 3.5 to 4.0.

In the method of the present invention, most tow stretching occurs in the first or initial stretching step or zone as mentioned above. Specifically, 85% to 97.5% of the total amount of stretch imparted to the tow, including 92% to 97%, is made in the first or initial stretching step or zone. The stretching operation in the first or first stage can generally be performed at any temperature the filament has when it is delivered from the quench zone of the melt spinning operation. Often, the first stage stretching temperature may range from 80 ° C to 125 ° C.

In the present invention, steam is introduced between feeding and drawing to maximize nylon drawing. In one embodiment, a steam chamber disposed between the supply module and the elongation module is applied to enable a higher elongation ratio as compared to a normal elongation ratio as described herein.

The partially drawn tow is delivered to the second annealing and stretching step or zone where the tow is heated and further stretched from the first or initial stretching step or zone. The heating of the tow to perform the annealing serves to increase the crystallinity of the filament nylon polymer. In such a second annealing and stretching step or zone, the filaments of the tow are applied at an annealing temperature of 145 캜 to 205 캜, such as 165 캜 to 205 캜. In one embodiment, the temperature of the tow in such an annealing and stretching step can be achieved by contacting the tow with a steam-heated metal plate positioned between the first stage stretching and second stage stretching and annealing operations. In the present invention, annealing / oven drying under tension helps to remove excess moisture generated during the steam staring process.

After the annealing and stretching steps of the present method, the stretched and annealed tow is cooled to a temperature below 80 캜, such as below 75 캜. Throughout the stretching, annealing and cooling operations described herein, the tow is maintained under controlled tension, and thus relaxation is not allowed.

After stretching in the presence of steam, annealing / oven drying under tension, the multi-filament tow is converted into staple fibers in a conventional manner, for example using a staple cutter. Staple fibers formed from tows can often range in length from 2 to 13 cm (0.79 to 5.12 inches). For example, staple fibers can range from 2 to 12 cm (0.79 to 4.72 inches), from 2 to 12.7 cm (0.79 to 5.0 inches), or from 5 to 10 cm. The staple fibers herein may optionally be crimped.

The high strength Indian nylon staple fibers formed according to the process of the present invention will generally be provided as a collection of fibers having a denier per fiber of 1.0 to 3.0, such as a bale of fibers. When staple fibers having a denier per fiber of 1.6 to 1.8 are to be produced, a total effective draw ratio of 3.12 to 3.40, for example 3.15 to 3.30, can be used in the method of the present invention to provide staple fibers with the required load- have. When staple fibers having a denier per fiber of 2.5 to 3.0 or 2.3 to 2.7 are to be produced, it is desirable to provide staple fibers having the required load-bearing capacity in order to provide staple fibers with a total effective yield of 3.5 to 4.0, or 3.74 to 3.90 Draw ratio should be used. come

Using this process and subsequent annealing of the fibers at 180 ° C using standard annealing rollers produced much higher toughness fibers with a toughness greater than 7.5 g / den.

One non-limiting embodiment of the present invention discloses nylon staple fibers having a tenacity of greater than 7.5 g / den at break. In another non-limiting embodiment of the present invention, nylon staple fibers having a tenacity of greater than 7.8 g / den at break are disclosed. In another non-limiting embodiment of the present invention, nylon staple fibers having a tenacity of at least 8.0 g / deni at break are disclosed.

One non-limiting embodiment of the present invention discloses nylon staple fibers having a tenacity at 10% elongation of at least 4.0 g / den.

The fibers having the above properties may be used at lower blend ratios or may be spun into yarns using alternative spinning systems that meet existing fabric specifications while significantly reducing fabric manufacturing costs. Fibers with very high toughness (both fracture and tenacity at 7% or 10% elongation) potentially make fabrics made from these fibers stronger, cheaper and lighter. By using an alternative spinning system that lowers nylon blend levels and / or maintains fabric properties, such fibers can significantly reduce yarn spin and final fabric cost. This gives value to steam-downstream customers rather than competitors. To achieve these properties in the fibers, a steam chamber is used to maximize nylon elongation. The fiber strength obtained is higher than anything produced in normal staple equipment.

It is extremely advantageous to have the ability to produce much higher strength fibers than competitors. Yarn textile and fabric manufacturers can reduce costs while still meeting the strength requirements in the final fabric / garment due to higher strength nylon fibers. These higher intensities can put competitors in a disadvantageous position in terms of price. This price difference could potentially be between $ 0.34 and $ 1.00 / lb. Inexpensive yarn / fabric examples include the use of less nylon content in spinning yarns while still satisfying yarn and fabric strength requirements, and the use of inexpensive yarn spinning systems (Vortex or OES) while still meeting the fabric strength requirements. These low-cost alternatives will save more than $ 1.00 / fabric yards if implemented successfully enough. Having the ability to produce these higher strength fibers gives significant advantages that competitors can not achieve. Another possible advantage is that it can produce lighter fabrics / garments while still meeting existing fabric specifications. Competitive textile manufacturers will not be able to enter the market if new fibers, such as lighter textiles, are selected in any new fabric specification.

The nylon staple fibers provided herein are particularly useful for blending with other fibers for various types of textile applications. The blend may be made using some embodiments of nylon staple fibers in combination with other synthetic fibers, such as, for example, rayon or polyester. Examples of blends of nylon staple fibers herein include those made using natural cellulosic fibers such as cotton, linen, hemp, jute and / or ramie. Suitable methods for blending such fibers with affinity may include: mechanical blending of the mass of staple fibers prior to carding; Mechanical blending of the mass of staple fibers before and during carding; Or two or more passes through a staple fiber stretch blend before carding and after spinning.

In one embodiment, the present nylon staple fibers of high load-bearing capacity can be blended with cotton staple fibers and spun into textile yarns. Such yarns may be spun in a conventional manner using conventional staple and long staple spinning methods, including ring spinning, air spinning or vortex spinning, open end spinning, or friction spinning. If the yarn blend comprises cotton, the resultant textile yarn will typically have a cotton fiber to nylon fiber weight ratio of 20:80 to 80:20, including 40:60 to 60:40, often with cotton: nylon weight ratio Is 50:50. It is well known in the art that the nominal variation in fiber content, e.g., 52:48, is considered to be a 50:50 blend. Textile yarns made using the present nylon staple fibers of high load-bearing capacity often exhibit LEA product values of greater than 2800, such as greater than 3000, at a 50:50 NYCO content. Alternatively, such yarns may have a breaking strength of at least 17.5 or 18 cN / tex, including greater than 19 cN / tex at a 50:50 NYCO content.

In one embodiment, the present weaving yarn is made from nylon staple fibers having a denier per filament of 1.6 to 1.8. In yet another embodiment, the present textile yarns are made from nylon staple fibers having a denier per filament of 2.5 to 3.0, including 2.3 to 2.7.

The nylon / cotton (NYCO) yarns of some embodiments may be used in a conventional manner to produce NYCO woven fabrics having particularly desirable properties for use in military or other harsh applications. Thus, such yarns can be woven with 2x1 or 3x1 twill NYCO fabrics. Spun NYCO yarns, and 3x1 twill weave fabrics including such yarns are described in U.S. Pat. Are generally described and illustrated in patent number 4,920,000. The '000 patent is incorporated herein by reference.

Of course, NYCO woven fabrics include both warp and weft (weft) yarns. Some embodiments of woven fabrics are those having the present NYCO textile yarns woven with one or more, optionally all, of these directions. In one embodiment, the fabric of the present invention having particularly desirable durability and comfort has a weft (weft) direction woven yarn comprising the present nylon staple fibers having a denier per filament from 1.6 to 1.8, 3.0, and 2.3 to 2.7 denier, with nylon staple fibers of the present invention having a denier per filament of 2.3 to 3.0.

Some embodiments of woven fabrics made using yarns comprising the present high load bearing nylon staple fibers may use less nylon staple fibers than conventional NYCO fabrics while retaining many of the desirable properties of such conventional NYCO fabrics . Thus, such fabrics can be made to be relatively lightweight, low cost, yet still preferably durable. Alternatively, such fabrics may be made using the same or even greater amounts of nylon staple fibers of the present invention relative to the nylon fiber content of conventional NYCO fabrics, thereby enabling the fabric of the present invention to provide excellent durability characteristics.

Lightweight fabrics with some embodiments NYCO fabric is 200 g ^{/ m 2 (6.0 oz / yd} 2) below, and 175 g ^{/ m 2 (5.25 oz / yd} 2) , including less than 220 g / m ² (6.5 oz / yd < ² >). A suitable durable NYCO fabric of some embodiments will have a grab strength of greater than 190 lbs in an oblique direction and greater than 80 lbs in a weft (weft) direction. Other durable fabrics have a tear strength of at least 11.0 lbf (poundfeet) in an oblique direction and 9.0 lbf or more in a weft direction in a "as-made" fabric.

The present invention also relates to nonwoven fabrics comprising high strength Indian fibers and cellulose based or recycled synthetic or natural fibers. The present inventors have found that the addition of high strength Indian fibers imparts additional tensile strength, tear strength, abrasion, cleaning durability and service life to nonwoven substrates including, but not limited to, spun lace, airlaid, needle punch and other carded nonwoven techniques . In one embodiment, the high strength Indian fibers used in the nonwoven composite include load bearing nylon staple fibers having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / den at 10% elongation . However, as will be appreciated by those skilled in the art after reading this disclosure, alternative, high strength Indian fibers such as those disclosed in U.S. Patent Application Nos. 2011/0177737 and 2011/0177738 may also be used, Additional non-limiting nylon staple fibers having a relatively high load-bearing toughness that can be used in these nonwoven composites are disclosed in U.S. Patent Nos. 3,044,250; 3,188,790; 3,321,448; 3,459,845; 5,093,195 and 5,011,645. High strength Indian fibers are combined with a variety of cellulosic or regenerated synthetic or natural fiber technologies including, but not limited to, regenerated denim. End applications for nonwoven composites include, but are not limited to, industrial (felt / backing / filtration / insulation), clothing (including inner sensing), shoes, backpack / packed hard gear, durable and semi-durable (disposable or semi-disposable) Clothing or PPE, such as FR (chemically treated or combined with native FR fiber technology), biochemical products, or other special protective clothing.

Test Methods

It will be appreciated that when various parameters, characteristics and characteristics of the polymers, fibers, yarns and fabrics are specified, such parameters, characteristics and characteristics can be measured using the following types of test procedures and equipment:

Nylon Polymer Relative Viscosity

The formic acid RV of the nylon material used herein refers to the ratio of the solvent viscosity to the solution measured at 25 占 폚 in a capillary viscometer. The solvent is formic acid containing 10% by weight of water. The solution is an 8.4 wt% nylon polymer dissolved in a solvent. This test is based on ASTM Standard Test Method D 789. The formic acid RV is measured in a radiated filament before or after stretching and may be referred to as spinning fiber formic acid RV.

Strong measurement in staple fibers

All in Strong's measurements of staple fibers are made by fixing staple fibers in a single staple fiber, processing them appropriately, and averaging the measurements over ten or more fibers. In general, three or more sets of measurements (each for ten fibers) together provide a parameter value that is averaged and measured.

Filament denier

The denier is the linear density of filaments expressed in grams weight of filament 9000 meters. The denier can be measured on a Vibroscope from Textechno, Munich, Germany. The denier time (10/9) is the same as decitex (dtex). Denier per filament can be determined by gravimetric measurement according to ASTM Standard Test Method D 1577. The Favimat machine for vibration-based linear density measurements used in vibrooscopes is also used for denier measurements per filament of DPF or individual fibers and is equivalent to ASTM D1577

Toughness at break

The fracture toughness (T) is the maximum force or force at break of the filament, expressed in force per unit cross-sectional area. The toughness can be measured in an In Strong Model 1130 available from Strong Co. of Canton, Mississippi and is reported in grams per denier (grams per dtex). The filament strength (and elongation at break) at break can be measured in accordance with ASTM D 885.

Filament toughness at 7% and 10% elongation

The filament tenacity (T ₇ ) at 7% elongation is the force applied to the filament divided by the filament denier to achieve 7% elongation. T ₇ can be measured according to ASTM D 3822. The tenacity at 10% elongation is driven by Fabbite, which is equivalent to ASTM D 3822.

Yarn strength

The strength of the spinning nylon / cotton yarn herein can be quantified through Lea product value or yarn break strength. The Lea product and the fracture toughness of the filament yarn can be measured according to ASTM D 1578 as a normal measure of the average value of the weft yarn average strength. Lea product values are reported in units of pound force. The fracture toughness is recorded in units of cN / tex.

Fabric weight

The fabric weights or basis weights of the present weave fabrics are obtained by weighing a fabric sample of known area and calculating the weight or basis weight converted to grams / m ² or oz / yd ² according to the standard test procedure procedure of ASTM D 3776 Lt; / RTI >

Fabric Grab Strength

Fabric grab strength can be measured according to ASTM D 5034. Grab strength measurements are recorded in pound-force in both warp and weft directions.

Tear strength of fabrics - Elmendorf

The fabric tear strength can be measured according to ASTM D 1424 entitled " Standard Test Method for Tearing Strength of Fabrics by Falling-Pendulum Type (Elmendorf) Apparatus ". Grab strength measurements are recorded in pound-force in both warp and weft directions.

Fabric wear resistance - Taber

Textile abrasion resistance can be measured by the taber abrasion resistance measured according to ASTM D 3884-O1 entitled " Abrasion Resistance Using Double Head Abrader ". The results are recorded in terms of cycles to failure.

Fabric wear resistance - bending

Textile abrasion resistance can be measured by bending abrasion resistance measured according to ASTM D 3885 entitled " Standard Test Method for Abrasion Resistance of Textile Fabrics ". The results are recorded in terms of cycles to failure.

The following section further explains the synthetic fibers and their properties compared to the fibers produced by standard processes without the aid of steam draw. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention in any way.

Example

Example 1: Comparison of standard T420 versus high strength T420

The properties of the fibers produced according to the steam stretching assisted process of the present invention were compared after cutting and refining in fibers and fabrication equipment made by standard processes. The results are shown in Table 1.

Comparison of standard T420 versus high intensity T420 (Oerlikon analysis) fair DPF kidney (%) Toughness (g / den) Toughness @ 10% elongation (g / den) Supply-draw ratio Total stretching cost Standard T420 fiber 1.69 48 7.1 2.9 3.12 3.15 High strength T420 fiber 1.55 34 7.82 4.1 3.69 3.75 High strength T420 fiber 1.59 35.7 8 4.54 3.97 4.05

Claims (17)

A nylon staple fiber comprising a nylon polymer and having a tenacity of greater than 7.5 g / den. The nylon staple fiber of claim 1, wherein the nylon polymer is nylon 6,6. The nylon staple fiber of claim 1, wherein said tenacity at 10% elongation is greater than 4.0 g / den. Yarn emitted from the nylon staple fiber of any one of claims 1 to 4. 6. The yarn of claim 5, further comprising at least one accompanying staple fiber. 6. The method of claim 5, wherein the accompanying staple fibers are selected from the group consisting of cellulosics, modified cellulose-based products, animal fibers, salt-resistant polyesters, salt-resistant nylons, salt-resistant rayon, salt resistant cellulose, m-aramid, p-aramid, modacrylic, novoloid, melamine, polyvinyl chloride, antistatic fibers, PBO (1,4-benzenedicarboxylic acid, 4,6-diamino-1,3-benzenediol dihydrochloride and Of the polymer) and PBI (polybenzimidazole), and combinations thereof. A fabric comprising the nylon staple fiber of any one of claims 1 to 4 or the yarn of any one of claims 5 to 7. The fabric according to claim 8, wherein the weight is less than 6.0 oz./yd ² . The fabric of claim 8, wherein the fabric meets or exceeds established military fabric strength and tear specifications for fabrics weighing less than 6.0 oz./yd ² . At least a portion of which comprises the nylon staple fibers of claim 1. High strength Indian fibers and cellulose-based or recycled synthetic or natural fibers. The nonwoven composite of claim 12, wherein the high strength Indian fibers comprise load bearing nylon fibers having a breaking strength of greater than 7.5 g / den and / or a tenacity of greater than 4.0 g / den at 10% elongation. 14. The nonwoven fabric composite according to claim 12 or 13, wherein the cellulose-based or regenerated synthetic or natural fiber comprises regenerated denim. A method of making high strength or load-bearing nylon fibers comprising melt-spinning a nylon polymer into filaments, uniformly quenching the filaments and forming tows from the plurality of quenched filaments, stretching the tow in the presence of steam Comprising the steps of: (a) providing a plurality of staple fibers; (b) converting the resulting drawn and annealed tows into staple fibers. 16. The method of claim 15, wherein the annealing step is performed under tension. 17. The method of claim 15 or 16, wherein the nylon fiber has a breaking strength of greater than 7.5 g / den. 17. The method of claim 15 or 16, wherein the nylon fiber has a tenacity at 10% elongation greater than 4.0 g / den.