KR20200068656A - High load carrying capacity nylon staple fibers containing additives, and blended yarns and fabrics thereof - Google Patents

Abstract

Provided are nylon staple fibers containing additives that exhibit break tenacity greater than 6.5 g/den, as well as yarns, fabrics and other articles of manufacture produced from the fibers Is provided. A method of producing nylon staple fibers containing additives is also provided.

Description

High load carrying capacity nylon staple fibers containing additives, and blended yarns and fabrics thereof

This patent application claims the benefit of priority from U.S. Provisional Application No. 62/575091, filed October 20, 2017, the teachings of which are incorporated herein by reference in their entirety.

Technology field

The present invention relates to high load bearing nylon staple fibers containing additives, and methods of making them and their use in blended yarns, fabrics and other articles of manufacture.

Nylon has been commercially manufactured and used for many years. The first nylon fibers were poly (hexamethylene adipamide) nylon 6,6 fibers. Nylon 6,6 fibers are still commercially manufactured and used as major nylon fibers. Large quantities of other nylon fibers, especially nylon 6 fibers made from caprolactam, are also commercially produced and used. Nylon fibers are used in yarns for textile fabrics, and for other purposes. In the case of textile fabrics, there are essentially two main categories of yarns: continuous filament yarns and staple fibers, ie yarns made from cut fibers.

Nylon staple fibers are typically melt-spun nylon polymer to form filaments, the majority of these filaments are collected to form a tow, subjected to stretching operations on the tow, and then the tow, for example in a staple cutter Has been produced by converting to staple fibers. Tow usually contains thousands of filaments, and is generally hundreds of thousands (or more) in total denier. Stretching involves transferring the tow between a set of feed rolls and a set of draw rolls (which operate at a higher speed than the feed roll) to increase the orientation of the nylon polymer in the filament. Stretching is often combined with an annealing operation to increase nylon crystallinity in the tow filaments before the tow is converted to staple fibers.

One of the advantages of nylon staple fibers is that they are easily blended, especially with natural fibers, such as cotton (often referred to as short staples) and/or other synthetic fibers, to achieve derivable benefits from such blending. will be. Particularly preferred types of nylon staple fibers have been used for several years for blending with cotton, in particular to improve the durability and economy of fabrics made from yarns comprising a blend of cotton and nylon. This includes Hebeler's U.S. Patent No. 3,044,250; 3, 188,790; 3,321,448; And 3,459,845, because such nylon staple fibers have a relatively high load-bearing tenacity, and these patents are incorporated herein by reference in their entirety. As described by Hebeler, the load-bearing capacity of nylon staple fibers is conveniently measured as the toughness at 7% elongation (T7), and the T7 parameter has long been tolerated as a standard measurement and is easily read on Instron machines. do.

The Hebeler process for producing nylon staple fibers involves the nylon spinning, tow forming, stretching and conversion operations described above. Subsequently, improvements in the Hebeler process for producing nylon staple fibers have been made by changing the properties of the tow drawing operation and adding certain types of annealing (or high temperature treatment) and subsequent cooling steps to the overall process. For example, Thompson's U.S. Patent Nos. 5,093,195 and 5,011,645 disclose the production of nylon staple fibers, where, for example, nylon 6,6 polymers having a relative formic acid viscosity (RV) of 55 are spun to form filaments. , Followed by stretching, annealing, cooling, and cutting the filaments to form staple fibers, wherein the staple fibers have a toughness at break, T of about 6.8 to 6.9, a denier per filament of about 2.44, and load-bearing Ability, T7 is about 2.4 to 3.2. Such nylon staple fibers are further disclosed in the Thompson patent as being formed from yarns blended with cotton and having improved yarn strength. (Both of these Thompson patents are incorporated herein by reference in their entirety.)

Nylon staple fibers made according to Thompson technology are blended (typically in a 50:50 nylon/cotton ratio) into NYCO yarns, which are used to make NYCO fabrics. Such NYCO fabrics, such as woven fabrics, are applied in military combat clothing and clothing. Such fabrics have generally been demonstrated to be satisfactory for military or other rugged apparel applications, but military authorities, for example, are lighter/lighter, lower cost/lower, and more comfortable, Still looking for improved fabrics that may have high durability or even improved durability.

PCT/US2015/055333 provides high strength or load bearing nylon yarns with a break tenacity greater than 7.5 g/den and/or strength at 10% elongation greater than 4.0 g/den, as well as yarns, fabrics And articles of manufacture and methods of making them.

It is desired to add pigments, such as carbon black, to fibers, especially in military clothing, and the benefits have been found. See, for example, U.S. Patent No. 5,830,572, U.S. Patent No. 7,008,694 and U.S. Patent No. 7,320,766.

Moreover, denim and canvas fabrics, especially dark denim, especially black denim, have become popular in the market, but are known in the industry to have fading or colorfastness issues. For example, in the case of black denim, the color fades quickly after repeated washing/wearing. It is also known that the addition of nylon as a blend with cotton or cellulosic fibers significantly improves the durability of yarns and resulting fabrics by improving wear resistance. Black dyes used to dye black denim fabrics only dye nylon, and on nylon fibers they are not as dark or permanent as they are on cotton fibers.

However, any blending of nylon staples with cotton or cellulosic fibers requires high strength/high modulus.

Addition of additives such as pigments into the polymer prior to melt spinning of the fiber has historically reduced fiber physical properties. For example, organic pigments tend to crosslink nylon, change its viscosity, form spherulites that weaken fibers, and cause increased stretch tension and filament breakage. The more pigments added, the greater the strength loss. These reduced fiber properties have hindered or limited the blending of pigmented nylon staples and cellulosic fibers, as they cause low yarn strength and low fabric strength problems.

For example, DuPont produced pigmented nylon staples for use in automotive upholstery in the mid to late 1990s. The resulting nylon staple product had a fracture toughness of less than 5.5 grams/denier. The only end use identified at that time was for yarns to be spun in 100% form for automotive/home decor materials.

U.S. Patent No. 5,290,850 discloses an improved process for melt spinning a pigmented hexamethylene adipamide fiber from a melt blend of polymer and colored pigment, wherein the polymer has a toughness of greater than 7.5 grams/denier. It is a random interpolyamide or block polymer having two different bifunctional repeating amide-forming moieties in addition to those that form hexamethylene, as indicated.

There is a need for additional high load bearing nylon staple fibers containing additives for use in textiles and other articles of manufacture.

Usually, adding any inorganic or organic pigments or additives to the polymer during the melt spinning process reduces the fiber strength obtained. Loss of fiber strength lowers the strength of the yarn and consequently the fabric strength. The inventors unexpectedly found that the process of adding the additives into the nylon polymer prior to fiber formation and stretching/annealing the fibers under steam assistance results in the production of high strength/high modulus fibers containing the additives.

Accordingly, one aspect of the present invention relates to nylon staple fibers comprising a nylon polymer and additives. The nylon staple fiber containing the additive of the present invention exhibits a fracture toughness greater than 6.5 g/den. In one non-limiting embodiment, the nylon staple fiber exhibits toughness at 10% elongation greater than 3.0 g/den. Non-limiting examples of additives that may be included in these fibers include pigments, as well as additives included for fire or flame (FR) resistance and/or ultraviolet (UV) protection.

Another aspect of the invention relates to a yarn spun from nylon staple fibers. In one non-limiting embodiment, the yarn further comprises at least one companion staple fiber. In one non-limiting embodiment, the nylon content of the yarn is greater than 5%. In one non-limiting embodiment, the nylon content of the yarn is greater than 30%. In one non-limiting embodiment, the nylon content of the yarn is greater than 50%. Such yarns can be made of fabrics and other articles of manufacture, which are advantageously lightweight, comfortable, low cost, durable, and thus, for example, in military clothing, such as combat clothing or other tough use clothing, or It is particularly suitable for use as.

Another aspect of the invention relates to an article of manufacture comprising at least a portion of the nylon staple fibers or yarns of the invention.

In one non-limiting embodiment, the article of manufacture is a fabric.

In one non-limiting embodiment, the fabric is dyed solid color and/or exhibits a uniform dark shade.

In one non-limiting embodiment, the fabric exhibits improved UV light fastness compared to the closest companion fabric lacking such pigment-containing or additive-containing components.

In one non-limiting embodiment, the fabric exhibits improved dye wash fastness compared to the closest companion fabric lacking such pigment-containing or additive-containing components.

In one non-limiting embodiment, the fabric is a camouflage print. Such fabrics are typically constructed by use of pigmented synthetic fibers, such as polyamide 6,6 or nylon 6,6, but the fabric can also be a greige or pigment-free fabric. However, even when the fibers are pigmented, printing may still occur on top of the pigmented fabric.

In one non-limiting embodiment, the fabric exhibits NIR (Near Infrared) reflectance in the 600 to 900 nm range and/or lower and flattened SWIR (Short Wave Infrared) reflectance in the 900 to 2500 nm range. In addition, the fabric increases the infrared (IR) reflectance curve separation between the individual colors used in the printed fabric in the SWIR spectrum, and provides additional disturbance and improved camouflage effects for night vision goggle surveillance.

In one non-limiting embodiment, the fabric has improved flame resistance properties.

In one non-limiting embodiment, the fabric exhibits improved electrical arc rating compared to the closest companion fabric lacking such pigment-containing or additive-containing components.

In one non-limiting embodiment, the article of manufacture is a denim fabric. In one non-limiting embodiment, the denim fabric is overdyed with a color similar to the pigment contained in nylon staple fibers. In addition, when the fibers are black and the fabric is printed in a dark color, a more uniformly dyed product is obtained because the black fibers will act to minimize or eliminate the appearance of the white fibers seen through the fabric.

In another non-limiting embodiment, the article of manufacture is a nonwoven fabric composite. End uses for such composites include industrial (felt/backing/filtration/insulation), clothing (including lining fabrics), footwear, backpack/pack hard gear, durable and semi-durable (disposable or semi-disposable) clothing, or PPE-including but not limited to FR (including chemically treated or combined with proprietary FR fiber technology), biochemical, or other specialty protective clothing.

Another aspect of the present invention relates to a method of producing high strength or load bearing pigmented nylon staple fibers. The method of the present invention comprises melt-spinning a nylon polymer containing a pigment to form a filament, followed by uniformly quenching the filament, and forming a tow from a plurality of the quenched filaments. Includes. The tow is then stretched in the presence of steam. The stretched tow is then annealed, and the resulting stretched and annealed tow is converted into staple fibers. In one non-limiting embodiment, annealing is performed under tension. The nylon staple fibers produced according to this method have a fracture toughness of greater than 6.5 g/den. In one non-limiting embodiment, nylon staple fibers prepared according to this method have a toughness at 10% elongation of greater than 3.0 g/den.

High-strength or load-bearing nylon staple fibers, yarns, fabrics and at least a portion of them containing additives, wherein the breaking toughness is greater than 6.5 g/den and/or the strength at 10% elongation is greater than 3.0 g/den. Other articles of manufacture made from fibers, and methods for their production, are provided by this specification.

Non-limiting examples of additives included in nylon staple fibers include pigments, additives that provide UV protection, and additives for FR resistance.

In one non-limiting embodiment, the additive is a pigment present in an amount from about 10 ppm (parts per million) to about 50,000 ppm. In one non-limiting embodiment, the pigment is carbon black. Additional examples of suitable pigments include: ultramarine violet, sulfur containing sodium and aluminum silicates; Han purple, BaCuSi ₂ O ₆ ; Cobalt violet, first cobalt orthophosphate; Manganese violet, NH ₄ MnP ₂ O ₇ ; Ultramarine, Na _8-10 Al ₆ Si ₆ O ₂₄ S _2-4 ; Persian blue, (Na, Ca) ₈ (AlSiO ₄ ) ₆ (S,SO ₄ ,Cl) _1-2 ; Cobalt blue, cobalt stannate (II); Egyptian Blue, (CaCuSi ₄ O ₁₀ ); Han blue, BaCuSi ₄ O ₁₀ ; Azurite, (Cu ₃ (CO ₃ ) ₂ (OH ₂ )); Prussian blue, ferric hexacyanoferrate; YInMn blue, (Yln _1-x Mn _x O ₃ ); Cadmium green, a mixture of CdS and Cr ₂ O ₃ ; Chromium green, chromium oxide; Virdian, hydrated chromium oxide; Rinman's green, CoZnO ₂ ; Malachite, (Cu ₂ CO ₃ (OH) ₂ ); Paris Green, Cu(C ₂ H ₂ O ₂ ) _2.3 Cu(AsO ₂ ) ₂ ); Schele's green, CuHAsO ₃ ; Verdigris, which is typically cupric acetate and/or malachite; Verona green, (K[(Al,Fe ^III ),(Fe ^II ,Mg](AlSi ₃ ,Si ₄ )O ₁₀ (OH) ₂ ); orpiment, (As ₂ S ₃ ) ; Primrose Yellow, (BiVO ₄ ); Cadmium Sulfide, CdS; Chromium Yellow, PbCrO ₄ ; Cobalt Yellow, (K ₃ Co(NO ₂ ) ₆ ); Yellow Ocher, (Fe ₂ O ₃ .H ₂ O); Titanium Yellow; mosicic gold, SnS ₂ ; cadmium orange, cadmium sulfoselenide; chromium orange, (PbCrO ₄ + PbO); realgar, AS ₄ S ₄ ; cadmium red, CdSe; Indian red; red ocher , Fe ₂ O ₃ ; Burnt Siena; Vermillion, HgS; raw umber, Fe ₂ O ₃ + MnO ₂ + nH ₂ O + Si + AlO ₃ ; raw sienna; ivory black; Vine Black ; Lamp black; mars black, Fe ₃ O ₄ ; manganese dioxide; titanium black, Ti ₂ O ₃ ; antimony white, Sb ₂ O ₃ ; barium sulfate; lysophone, BaSO ₄ .ZnS; Kremnitz white (Cremnitz white), ((PbCO ₃ ) ₂ -Pb(OH) ₂ ); titanium dioxide, TiO ₂ ; and zinc oxide, ZnO.

Non-woven fabric composites comprising high toughness fibers and cellulosic or regenerated synthetic or natural fibers are also provided by this specification.

As used herein, the terms “durable” and “durable”, in the tendency of fabrics, have moderately high grab and tear strength, as well as wear resistance for the intended end use of such fabrics. It refers to the tendency of the fabric to be characterized as having, and having such desirable properties for an appropriate time after the use of the fabric is started.

As used herein, in referring to spun yarn, the term “blend” or “blended” refers to a mixture of at least two types of fibers, the mixture of each fiber type. The individual fibers are formed in such a way that they are substantially completely intermixed with other types of individual fibers to provide a substantially homogeneous fiber mixture, the fiber mixture having sufficient entanglement to maintain its integrity upon further processing and use. Have

As used herein, cotton count refers to a yarn numbering system based on a length of 840 yards, and the number of yarns is the amount of 840-yard skein required to weigh 1 pound. Sue.

It is understood that all numerical values recited herein are modified by the term “about”.

Some embodiments are based on the production of improved nylon staple fibers containing additives having certain specified properties, and based on yarns, and subsequent production of fabrics woven from such yarns, where these improved nylons containing additives Staple fibers are blended with at least one other fiber. Other fibers include cellulosic materials such as cotton, modified cellulosic materials such as fire-resistant (FR) treated cellulose, polyester, rayon, animal fibers such as wool, FR polyester, FR nylon, FR rayon, m-aramid, p-aramid , Modacrylic, novoloid, melamine, polyvinyl chloride, antistatic fiber, PBO (polymer with 1,4-benzenedicarboxylic acid, 4,6-diamino-1,3-benzenediol dihydrochloride) , PBI (polybenzimidazole), and combinations thereof. Nylon staple fibers of some embodiments can provide yarns and fabrics with an increase in strength and/or wear resistance. This is especially true in combination with relatively weaker fibers, such as cotton and wool.

Specific properties of the nylon staple fibers containing additives, which are made and used herein, include fiber load-bearing ability defined in terms of fiber denier, fiber toughness, and fiber toughness at 7% and 10% elongation. do.

The realization of the desired nylon staple fibers containing the additive material of the present invention is based on the use of nylon polymer filaments and tows with certain selected properties in the manufacture of staple fibers and they are processed using certain selected processing operations and conditions. . Specifically, the present inventors considerably prevent or prevent the reduction in strength associated with the addition of such fiber additives by the tension during the introduction and/or annealing of steam between the feed module and the stretching module during the production of nylon staple fibers containing the additives. Found out. In one non-limiting embodiment of the present invention, steam is introduced into the process by adding a steam chamber between the feed module and the draw module, as this allows excess water to be removed prior to annealing. Without being limited to any particular theory, the steam chamber applies sufficient heat/steam to reduce the stretching force of the nylon, and localizes the stretching into the steam chamber so that the stretching is not at the feed roll outlet point or beyond the feed roll outlet. It is believed to help. Steam can be controlled by pressure.

The nylon polymer itself used for spinning the nylon filaments of the present invention can be produced in a conventional manner. Nylon polymers suitable for use in the process and filaments of some embodiments include melt spunable or melt spun synthetic polymers. Such nylon polymers can include polyamide homopolymers, copolymers, and mixtures thereof, which are predominantly aliphatic, ie less than 85% of the amide linkages of the polymer are attached to two aromatic rings. Widely used polyamide polymers such as nylon 6,6 poly(hexamethylene adipamide) and nylon 6 poly(ε-caproamide) and copolymers thereof and mixtures thereof can be used in accordance with some embodiments. . Other polyamide polymers that can be advantageously used are nylon 12, nylon 4,6, nylon 6,10, nylon 6,12, nylon 12,12, and copolymers thereof and mixtures thereof. Exemplary polyamides and copolyamides that can be used in some embodiments of the process, fibers, yarns, and fabrics are described in U.S. Pat.Nos. 5,077,124, 5,106,946, and 5,139,729 (each granted to Cofer et al., respectively). And polyamide polymer mixtures disclosed by Gutmann in Chemical Fibers International, pages 418-420, Volume 46, December 1996. All of these publications are incorporated herein by reference.

In one non-limiting embodiment, the polymer can further include a monomer salt of a sulfonated isophthalate (SIPA) or a monomer methylpentamethylenediamine (MPMD). In one non-limiting embodiment, the monomer is added in an amount of about 0.04 to about 4% by weight of the nylon polymer.

Nylon polymers used in the manufacture of nylon staple fibers are typically suitable monomers, catalysts, antioxidants and other additives (plasticizers, delustrants, pigments, dyes, light stabilizers, heat stabilizers, antistatic agents to reduce static electricity) , Including, but not limited to, additives for altering dye ability, agents for altering surface tension, and the like. Polymerization has typically been carried out in continuous polymerizers or batch autoclaves. The resulting molten polymer is then typically introduced into a spin pack, where it is pressed through a suitable spinneret to form a filament, the filament is quenched, and then for final processing into nylon staple fibers. It is formed of tow. As used herein, the spinning pack consists of a pack lid at the top of the pack, a spinneret plate at the bottom of the pack, and a polymer filter holder interposed between the two preceding components. The filter holder has a central recess therein. The lid and the recess in the filter holder cooperate to form a closed pocket, in which the polymeric filter medium, such as sand, is accommodated. A channel is provided inside the pack so that the flow of molten polymer supplied by the pump or extruder can travel through the pack and finally through the spinneret plate. The spinneret plate has an array of small precision bore extending through it, which transports the polymer to the bottom surface of the pack. The inlets of the bores form an array of orifices on the lower surface of the spinneret plate, which lower surface forms the top of the quench zone. The polymer exiting these orifices is in the form of filaments, and then the filaments go straight down through the quench zone.

The degree of polymerization performed in a continuous polymerizer or batch autoclave can be quantified by a parameter commonly known as relative viscosity or RV. RV is the ratio of the viscosity of the solution of the nylon polymer in the formic acid solvent to the viscosity of the formic acid solvent itself. RV is accepted as an indirect indicator of the molecular weight of the nylon polymer. For the purposes of the present invention, an increase in nylon polymer RV is considered synonymous with an increase in nylon polymer molecular weight.

As the nylon molecular weight increases, its processing becomes more difficult due to the increase in the viscosity of the nylon polymer. Thus, a continuous polymerizer or batch autoclave is typically operated to provide a nylon polymer for final treatment with staple fibers, where the nylon polymer has an RV value of about 60 or less.

For some purposes, it is known that the provision of larger molecular weight nylon polymers, i.e., nylon polymers having a RV value of greater than 70 to 75 and up to 140 or even 190 or higher, may be advantageous. For example, this type of high RV nylon polymer is known to have improved resistance to flexural wear and chemical degradation. Thus, such high RV nylon polymers are particularly suitable for spinning to form nylon staple fibers, which can be advantageously used in the manufacture of papermaking felts. US Pat. Nos. 5,236,652 to Kidder and US Pat. No. 6,235,390 to Schwinn and West; procedures and apparatus for making high RV nylon polymers and staple fibers therefrom; No. 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 that generally match or generally have higher RV values in some cases than those generally obtained through polymerization in a continuous polymerizer or batch autoclave, with additives and herein When processed according to the described spinning, quenching, feeding, and drawing and annealing procedures in the presence of steam, unexpectedly, at increased fiber break toughness and increased 10% elongation, in contrast to standard products or previously described improvements. It was found to indicate the toughness of. When such nylon staple fibers containing additives with improved toughness are blended with one or more other fibers, such as cotton staple fibers, improved strength as well as lower weight textile yarns can be realized. Fabrics woven from such yarns, such as NYCO fabrics, exhibit the advantages of durability, optional light weight, improved comfort and/or potentially lower cost described above, as well as the benefits of selected additive color, UV protection or FR resistance.

According to the staple fiber manufacturing process of the present specification, nylon polymers containing additives, which are melted and melted through one or more spinning pack spinnerets to form and quench, have an RV value of 45 to 100 (55 to 100, 46) To 65, 50 to 60, and 65 to 100). Nylon polymers of such RV properties can be prepared, for example, using melt blending procedures of polyamide concentrates, such as those disclosed in the Kidder '652 patent described above. Kidder discloses certain embodiments in which a catalyst is added for the purpose of increasing formic acid relative viscosity (RV). Higher RV nylon polymers available for melting and spinning, such as nylon with an RV of 65 to 100, can also be provided by a solid phase polymerization (SPP) step, where the nylon polymer flakes or granules are conditioned to increase the RV to the desired level. do. Such solid phase polymerization (SPP) procedures are well known and are well described in detail in the aforementioned Schwinn/West '390, '694, '129 and '939 patents.

Nylon polymer material containing additives, having the required RV properties as specified herein, is supplied to the spinning pack, for example through a twin-screw melter device. In one non-limiting embodiment, a volumetric or gravimetric feeder is used for the addition of additives. Within the spin pack, the nylon polymer containing the additive is spun by extrusion through one or more spinnerets to form multiple filaments. For the purposes of the present invention, the term "filament" is defined as a relatively flexible and macroscopically homogeneous body having a high length to width ratio across a cross-sectional area perpendicular to the length. The filament cross section can be of any shape, but is typically circular. In this specification, the term “fiber” may also be used interchangeably with the term “filament”.

Each individual spinneret location can accommodate 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 machine can accommodate from 1 to 96 locations, each of which provides a filament bundle, which are finally combined into a single tow band for stretching/downstream processing with other tow bands. Becomes

After exiting the spinneret, the molten filament extruded through each spinneret typically passes through the quench zone, where various quench conditions and configurations are used to solidify the molten polymer filaments containing the additives and bring them together. It can be collected and adapted to form a tow. Quenching is most commonly by passing a cooling gas, such as air, through, through, around, and through the filament bundles extruded into the quench zone from each spinneret location in the spin pack. Is performed.

One suitable quench configuration is cross-flow quench, where the cooling gas, such as air, is pressed into the quench zone in a direction substantially perpendicular to the direction in which the extruded filament is moving through the quench zone. . Among other quench configurations, the cross-flow quench arrangement is described in US Pat. No. 3,022,539; 3,070,839; 3,336,634; 5,824,248; 5,824,248; 6,090,485, 6,881,047 and 6,926,854, the teachings of which are incorporated herein by reference in their entirety.

In one non-limiting embodiment of the staple fiber manufacturing process of the present invention, the extruded nylon filament containing additive, which is finally used to form the desired nylon staple fiber containing the additive, is disclosed in U.S. Patent Application Publication No. 2011/0177737 It is spun, quenched, formed into tow, using both positional uniformity and uniformity of quench conditions as described in heading and 2011/0177738, the teachings of which are incorporated herein by reference in their entirety. do.

The quenched spun filaments can then be combined into one or more tows. Subsequently, such tows formed from filaments from one or more spinnerets undergo a two-stage continuous operation, where the tows are stretched and annealed in the presence of steam.

Stretching of the tow is usually carried out primarily in the initial or first stretching stage or zone, where the tow band is passed between a set of feed rolls and a set of stretching rolls (which operate at higher speeds) of the filaments in the tow. Increase the crystal orientation. The degree to which the tow is stretched can be quantified by specifying the draw ratio, which is the ratio of the higher peripheral speed of the draw roll to the lower peripheral speed of the feed roll. The effective stretching ratio is calculated by multiplying the first stretching ratio by the second stretching ratio.

The first draw stage or zone may include several sets of feed rolls and draw rolls, as well as other tow guide and tensioning rolls, such as snubbing pins. The stretch roll surface can be made of metal, for example chrome or ceramic. It has been found that the ceramic stretch roll surface is particularly advantageous in enabling the use of relatively higher draw ratios specified for use in connection with the staple fiber manufacturing process herein. Ceramic rolls not only improve roll life, but also provide a less prone surface to wrap. Papers representing the International Fiber Journal, incorporated herein by reference (International Fiber Journal, 17, 1, February 2002: "Textile and Bearing Technology for Separator Rolls", Zeitz and el.) In addition, US Pat. No. 4,794,680 also discloses the use of ceramic rolls to improve roll life and reduce fiber adhesion to roll surfaces.

The maximum degree of stretching of the tow of the filaments of the present invention occurs in the initial or first stretching stage or zone, but generally also some additional stretching of the tow will occur in the second or annealing and stretching stage or zone described below. The total amount of stretching applied to the filament tow of the present invention is by specifying the total effective draw ratio that takes into account the stretching that occurs in both the first initial stretching stage or zone and the second zone or stage (here annealing and some additional stretching are performed simultaneously). Can be quantified.

In the process of some embodiments, a total effective draw ratio of 2.3 to 5.0 (including 3.0 to 4.0) is applied to the tow of the nylon filament containing the additive. In one embodiment where the denier per filament of the tow is generally smaller, the total effective draw ratio may range from 3.12 to 3.40. In other embodiments where the denier per filament of the tow is generally greater, the total effective draw ratio may range from 3.5 to 4.0.

In the process of the present invention, as previously mentioned, most of the tow's stretching takes place in the first or initial stretching stage or zone. In particular, 85% to 97.5% (including 92% to 97%) of the total amount of stretch imparted to the tow will occur in the first or initial stretching stage or zone. Generally, the stretching operation in the first or initial stage will be performed at any temperature that the filament has when passing from the quench zone of the melt spinning operation. Frequently, this first stage stretching temperature will range from 80°C to 125°C.

In the present invention, steam is introduced between supply and stretching. In one embodiment, a steam chamber positioned between the feed module and the draw module is used.

From the first or initial stretching stage or zone, the partially stretched tow is delivered to the second annealing and stretching stage or zone, where the tow is heated simultaneously and further stretched. Heating the tow to achieve annealing serves to increase the crystallinity of the nylon polymer of the filament. In this second annealing and stretching stage or zone, the filament of the tow is subjected to an annealing temperature of 145°C to 205°C, such as 165°C to 205°C. In one embodiment, the temperature of the tow in this annealing and stretching stage can be achieved by contacting the tow with a steam-heated metal plate positioned between the first stage stretching operation and the second stage stretching and annealing operation. In the present invention, annealing/oven drying under tension helps to remove excess moisture obtained during steam stretching.

After the annealing and stretching stages of the process of the present invention, the stretched and annealed tow is cooled to a temperature below 80°C, such as below 75°C. Throughout the stretching, annealing and cooling operations described herein, the tow is maintained under controlled tension and thus cannot be relaxed.

After stretching in the presence of steam and annealing/oven drying in tension, the multifilament tow is converted to staple fibers containing additives in any conventional manner, for example by using a staple cutter. Staple fibers containing additives, formed from tow, will frequently range in length from 2 to 13 cm (0.79 to 5.12 inches). For example, staple fibers containing additives can range from 2 to 12 cm (0.79 to 4.72 inches), 2 to 12.7 cm (0.79 to 5.0 inches), or 5 to 10 cm. Staple fibers containing the additives of the present invention can be optionally crimped.

The high toughness nylon staple fibers containing additives, 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, for example as a bale of fibers. When staple fibers having deniers per fiber of 1.6 to 1.8 are produced, a total effective draw ratio of 3.12 to 3.40, such as 3.15 to 3.30, can be used to provide staple fibers of the load-bearing ability required in the process of the present invention. When staple fibers with deniers per fiber of 2.5 to 3.0 or 2.3 to 2.7 are produced, a total effective draw ratio of 3.5 to 4.0 or 3.74 to 3.90 should be used to provide staple fibers of the load-bearing capacity required in the process of the present invention. do.

Using this process and then using standard annealing rolls to anneal the fibers containing the additives at 180° C., significantly higher toughness fibers containing additives with toughnesses greater than 6.5 g/den were produced.

In one non-limiting embodiment of the present invention, nylon staple fibers containing additives are disclosed wherein the toughness at 10% elongation is at least 3.0 g/den.

Fibers that have the above properties and have the added advantage of the present invention of additives in the fibers, such as pigments, UV protectors and FR resistors, can be used at lower blend ratios or spun using alternative spinning systems to form yarns. Which significantly reduces fabric manufacturing costs and still meets existing fabric specifications. Such fibers can be used to significantly reduce yarn spinning and final fabric costs by enabling lower nylon blend levels and/or use of alternative spinning systems while maintaining fabric properties.

Nylon staple fibers containing the additives provided herein are particularly useful for blending with other fibers for various types of textile applications. Blends can be made, for example, by combining nylon staple fibers of some embodiments with other synthetic fibers, such as rayon or polyester. Examples of blends of nylon staple fibers of the present invention include natural cellulosic fibers, such as those made from cotton, flax, hemp, jute and/or ramie. Suitable methods for intimately blending these fibers may include: bulk mechanical blending of staple fibers prior to carding; Bulk mechanical blending of staple fibers before and during carding; Or at least two passes of stretching frame blending of staple fibers following carding and before yarn spinning.

According to one non-limiting embodiment, the high load-bearing nylon staple fibers containing the additives of the present invention can be blended and spun with cotton staple fibers to form textile yarns. Such yarns can be spun in conventional manner using commonly known short and long staple spinning methods, including ring spinning, air jet or vortex spinning, open end spinning, or friction spinning. When the yarn blend comprises cotton, the resulting textile yarns generally have a cotton fiber to nylon fiber weight ratio of 10:90 to 90:10 (including 30:70 to 70:30), and frequently cotton:nylon weight ratio. Would be 50:50. It is well known in the art that nominal variations in fiber content, such as 52:48, are also considered to be 50:50 blends.

Nylon/cotton (NYCO) yarns of some embodiments can be used in a conventional manner to produce NYCO woven fabrics having properties particularly desirable for use in military or other tough use clothing. Thus, such yarns can be woven from 2x1 or 3x1 twill NYCO fabrics. Spinned NYCO yarns and 3x1 twill fabrics comprising such yarns are generally described and illustrated in US Pat. No. 4,920,000 to Green, which is incorporated herein by reference.

Of course, NYCO woven fabrics include both warp yarns and weft (weft) yarns. The woven fabrics of some embodiments are those in which the NYCO textile yarn of the present invention is woven in at least one of these directions, optionally in both directions. In one embodiment, fabrics of the present invention with particularly desirable durability and comfort will have yarns woven in the weft (weft) direction comprising nylon staple fibers containing the additives of the present invention, and containing the additives of the present invention. It will have yarns woven in an oblique direction comprising nylon staple fibers.

Woven fabrics of some embodiments made using yarns comprising high load bearing nylon staple fibers containing the additives of the present invention are capable of using fewer nylon staple fibers than conventional NYCO fabrics, but many of such conventional NYCO fabrics are available. It can retain desirable properties. Thus, such fabrics can still be manufactured with relatively light weight and low cost while still being durable. Alternatively, such fabrics can be made using the same or even higher amounts of nylon staple fibers containing the additives of the present invention, compared to the nylon fiber content of conventional NYCO fabrics, wherein such fabrics of the present invention Provides superior durability properties.

In one non-limiting embodiment, nylon staple fibers of the present invention containing pigment additives are used to produce articles of manufacture, such as denim fabrics. Currently, 100% cotton denim fabric dyed in black has a problem of fading and abrasion after repeated washing. Pigmented high strength nylon staples can be added to improve fabric durability and strength, but fade problems remain. The addition of pigmented high strength nylon staples of the present invention comprising additives, such as carbon black, reduces black appearance loss and improves wear life. Alternative pigments may also be used for colors such as blue, green and tan, as understood by those skilled in the art upon reading this specification. In this non-limiting embodiment, 1-5% by weight of pigmented fibers having, for example, carbon black or denim blue pigments can be used in denim to reduce fabric fading problems and improve durability. Incorporation of these fibers into fabrics is particularly useful for articles of manufacture that are dyed monochromatic and/or require improved uniformity in dyeing, such as in dark shades.

In some embodiments, the denim fabric can be over-dyed with a color similar to the pigment contained in nylon staple fibers. In addition, camouflage printed fabrics can be produced from nylon staple fibers containing the additives of the present invention.

It is expected that such fabrics will show improved dye wash fastness.

In addition, the addition of carbon black into or on fabric as a topical treatment is known to improve concealment/wearer concealment when observed through night vision goggles using near infrared (NIR) and short wavelength infrared (SWIR) techniques. have.

Thus, in another non-limiting embodiment, the pigmented nylon staple fibers of the present invention containing carbon black in the range of 10 to 1000 ppm are manufactured articles containing the fibers when observed under SWIR/IR night vision goggles, such as Can be used to improve the concealment of uniforms. In one non-limiting embodiment, the introduction of pigmented nylon staple fibers of the present invention comprising conventional dyes does not require any pre-treatment or post-treatment or the use of metalized or special pigment formulations and visible light. The NIR reflectance can be lowered in the range of 600 to 900 nm without significantly changing the shadow in the spectrum, thereby improving gastrointestinal disturbance and effectiveness for night vision goggle surveillance.

In another non-limiting embodiment, the introduction of the pigmented nylon staple fiber of the present invention comprising conventional dyes is a pre-treated or post-treated or metalized or special pigment formulation required for monochromatic and printed camouflage NYCO fabrics. It can lower and flatten short wavelength infrared reflectance (SWIR) in the 900 to 2500 nm range without requiring the use of and without significantly changing the shade in the visible light spectrum, thus camouflage disturbance for night vision goggle surveillance and Effectiveness can be improved. In another non-limiting embodiment, the introduction of pigmented nylon staple fibers of the present invention comprising conventional dyes is from 900 to 900 without the need for any pre-treatment or post-treatment or the use of metalized or special pigment formulations. It is possible to increase the level of separation between print colors in the SWIR in the 2500 nm range, thereby improving gastrointestinal disturbance and effectiveness for night vision goggles surveillance. It is also expected that such fabrics of the present invention will exhibit improved electrical arc ratings.

In another non-limiting embodiment, the introduction of a nylon staple fiber into an article of manufacture, such as a fabric, an additive that provides UV protection or an additive that provides FR resistance, results in improved UV light fastness and/or flame retardancy.

The present invention also relates to a nonwoven fabric composite comprising the high toughness fibers of the present invention. High toughness fibers can be combined with various cellulosic or regenerated synthetic or natural fiber technologies. In one embodiment, high toughness fibers are combined with recycled denim. End uses for non-woven fabric composites include industrial (felt/backing/filtration/insulation), apparel (including lining fabrics), shoes, bag/pack hard gear, durable and semi-durable (disposable or semi-disposable) clothing or PPE- Includes, but is not limited to, FRs (including chemically treated or combined with proprietary FR fiber technology), biochemicals, or other specialty protective clothing.

As understood by those skilled in the art upon reading this specification, those exemplified herein that have at least a portion on the top surface of the yarn or at least a portion on the bottom surface of the yarn having fibers that are permanently altered in cross section and fused together Alternative methods and apparatus for the use are available, the use of which is included in the present invention.

All patents, patent applications, test procedures, priority documents, papers, publications, manuals, and other documents cited herein are incorporated by reference in their entirety unless such disclosure is contrary to the present invention and in all jurisdictions where such inclusion is permitted. About

Test methods and examples

The following test methods and examples demonstrate the invention and its ability to use. The invention is capable of other and different embodiments, and some details of the invention can be modified in various obvious respects without departing from the scope and spirit of the invention. Therefore, the test methods and examples should be regarded as illustrative in nature and non-limiting.

Nylon polymer relative viscosity

The formic acid RV of the nylon material used herein refers to the ratio of solution viscosity and solvent viscosity measured on a capillary viscometer at 25°C. The solvent is formic acid containing 10% by weight water. The solution is 8.4% by weight nylon polymer dissolved in the solvent. This test is based on ASTM standard test method D 789. Formic acid RV, before and after stretching, is determined for the spun filament and can be referred to as spun fiber formic acid RV.

Instron measurement for staple fibers

All Instron measurements of the staple fibers of the present invention are made for a single staple fiber, with proper care by clamping the short fiber and averaging the measurements for at least 10 fibers. In general, at least three sets of measurements (for 10 fibers each) are averaged together to provide values for the parameters to be determined.

Filament denier

Denier is the linear density of a filament expressed as the weight (in grams) of the filament of 9000 meters. Denier can be measured on a Vibroscope from Textechno, Munich, Germany. Denier x (10/9) is the same as detex. Denier per filament can be determined gravimetrically according to ASTM Standard Test Method D 1577. Favimat machines with vibration-based linear density measurements such as those used in vibroscopes can also be used to determine denier per filament or DPF of individual fibers, similar to ASTM D1577.

Breaking Gangindo

The breaking toughness (T) is the maximum or breaking force of the filament expressed as the force per unit cross-sectional area. Toughness can be measured on an Instron model 1130 available from Instron, Canton, Massachusetts, USA, and is reported as grams per denier (g/dtex). The fracture toughness (and elongation at break) of the filament can be measured according to ASTM D 885.

Toughness at 7% and 10% elongation of filament

Toughness at 7% elongation of the filament (T7) is a value obtained by dividing the force applied to the filament by the filament denier to achieve 7% elongation. T7 can be determined according to ASTM D 3822. Toughness at 10% elongation can be performed on Favimat, which is similar to ASTM D3822.

Yarn strength

The strength of the spun nylon/cotton yarn of the present invention can be quantified through Le Product values or yarn break toughness. Lee products and skein stiffness are typical measures of the average strength of textile yarns and can be determined according to ASTM D 1578. Lee product values are reported in units of pound force. The fracture toughness is reported in cN/tex.

Fabric weight

The fabric weight or basis weight of the woven fabric of the present invention is determined by weighing a fabric sample of known area and calculating the weight or basis weight in terms of g/m ² or oz/yd ² according to the procedures of the standard test method of ASTM D 3776. You can.

Fabric grab strength

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

Fabric tear strength-Elmendorf

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 the oblique and weft directions.

Color Fastness to Laundry-AATCC Test Method 61

Using AATCC 61, color fastness to washing of textiles expected to withstand frequent washing is evaluated. The test specimen is attached to a multi-fiber swatch and the stainless steel ball is loaded into a stainless steel canister to simulate wear. The canister is then loaded into the machine and a 45 minute test begins. After washing, the specimens are dried, conditioned, and evaluated for both Gray Scale for Color Change and Gray Scale for Staining. The dimensional change of the fabric after washing is also tested and evaluated according to AATCC Test Method 135.

Color fastness to light-AATCC test method 16

This test method provides general principles and procedures currently in use to determine color fastness to textile materials. The test options described are applicable for all kinds of textile materials and for colorants, finishes and treatments applied to textile materials.

The test options included were:

1-Closed carbon-arc lamp, continuous light

2-closed carbon-arc lamp, alternating bright and dark

3-Xenon-arc lamp, continuous light, black panel optional

4-Xenon-Arc lamp, alternating bright and dark

5-Xenon-Arc lamp, continuous light, black standard option

6-Daylight Behind Glass

Colorimetric analysis

NIR and SWIR analysis is performed using any commercially available color spectrophotometer, such as UltraScan Pro spectrophotometer available from HunterLab.

Example 1:

Various fibers of the present invention were tested as described herein. The results are shown in Table 1 below.

[Table 1]

Claims (31)

As a nylon staple fiber,
Nylon polymer; And
Contains additives,
The nylon staple fiber has a break tenacity of greater than 6.5 g/den, a nylon staple fiber. The nylon staple fiber of claim 1, wherein the additive is selected from pigments, additives for UV (UV) protection, or additives for flame or fire (FR) resistance. The nylon staple fiber of claim 1, wherein the additive is a pigment present in an amount from about 10 ppm (parts per million) to about 50,000 ppm. The nylon staple fiber of claim 1, wherein the nylon polymer is selected from the group consisting of nylon 6,6, nylon 6, and combinations thereof. The nylon staple fiber of claim 1, wherein the nylon polymer further comprises a monomer salt of sulfonated isophthalate (SIPA) present in an amount of about 0.04 to about 4 weight percent of the nylon polymer. The nylon staple fiber of claim 1, wherein the nylon polymer further comprises monomer methylpentamethylenediamine (MPMD) present in an amount of about 0.04 to about 4 weight percent of the nylon polymer. The nylon staple fiber according to claim 1, wherein the toughness at 10% elongation is greater than 3.0 g/den. A yarn spun from the nylon staple fibers of claim 1. The yarn of claim 8, further comprising at least one companion staple fiber. The method of claim 9, wherein the accompanying staple fiber is a cellulosic material, a modified cellulosic material, animal fibers, fire-resistant polyester, fire-resistant nylon, fire-resistant rayon, fire-resistant treated cellulose, m-aramid, p-aramid, modacrylic, novoloid, Melamine, polyvinyl chloride, antistatic fiber, PBO (polymer with 1,4-benzenedicarboxylic acid, 4,6-diamino-1,3-benzenediol dihydrochloride) and PBI (polybenzimidazole ), and combinations thereof. 11. The yarn according to claim 1, wherein the nylon content is 5% or more. An article of manufacture comprising at least a portion of the nylon staple fiber of claim 1 or the yarn of claim 8. The article of manufacture of claim 12 which is a fabric. The article of manufacture of claim 12 which is a denim fabric. 15. The article of manufacture of claim 14, wherein the denim fabric is overdyed with a color similar to the pigment contained in the nylon staple fiber. The article of manufacture of claim 12 which is a nonwoven fabric composite. The article of manufacture of claim 16, wherein the nonwoven fabric composite further comprises a cellulosic or regenerated synthetic or natural fiber. 18. The article of manufacture of claim 17, wherein the cellulosic or recycled synthetic or natural fibers comprise recycled denim. The article of manufacture of claim 12, wherein the fabric is dyed solid color and/or exhibits a uniform dark shade. The article of manufacture of claim 12, wherein the fabric exhibits improved UV light fastness. The article of manufacture of claim 12, wherein the fabric exhibits improved dye wash fastness. 13. The article of manufacture of claim 12, wherein the fabric is a camouflaged print. The article of manufacture of claim 12, wherein the fabric exhibits reduced NIR (near infrared) reflectivity in the range of 600 to 900 nm. The article of manufacture of claim 12, wherein the fabric exhibits lower and flatter Short Wave Infrared (SWIR) reflectance in the range of 900 to 2500 nm. 13. The article of manufacture of claim 12, wherein the fabric is flame resistant. The article of manufacture of claim 12, wherein the fabric exhibits improved electrical arc rating. A method for producing high strength or load bearing nylon staple fibers containing additives,
Melt-spinning the nylon polymer containing the additive to form a filament;
Uniformly quenching the filament;
Forming a tow from a plurality of the quenched filaments;
Subjecting the tow to stretching in the presence of steam;
Annealing the stretched tow; And
And converting the resulting stretched and annealed tow into staple fibers. 28. The method of claim 27, wherein the additive is selected from pigments, additives for UV protection, or additives for FR resistance. 28. The method of claim 27, wherein annealing is performed under tension. The method according to any one of claims 27 to 29, wherein the nylon staple fiber has a breaking toughness of greater than 6.5 g/den. 31. The method of any one of claims 27-30, wherein the nylon staple fiber has a toughness at 10% elongation of greater than 3.0 g/den.