JP7242664B2 - High load-bearing nylon staple fibers with additives, blended yarns and fabrics thereof - Google Patents

Description

This patent application claims priority to US Provisional Patent Application No. 62/575091, filed October 20, 2017, the entire teachings of which are incorporated herein by reference.

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

Nylon has been manufactured and used commercially for many years. The first nylon fiber was nylon 6,6, poly(hexamethylene adipamide). Nylon 6,6 fibers are still manufactured and used commercially as the primary nylon fiber. Many other nylon fibers, particularly nylon 6 fibers prepared from caprolactam, are also produced and used commercially. Nylon fibers are used for yarn in textile fabrics and for other purposes. In woven fabrics, there are essentially two main categories of yarns: continuous filament yarns and yarns made from staple or chopped fibres.

Nylon staple fibers are conventionally made by melt spinning a nylon polymer into filaments, collecting a large number of these filaments into tows, subjecting the tows to a drawing operation, and then converting the tows into staple fibers, for example with a staple cutter. It has been made by A tow typically contains thousands of filaments, generally on the order of hundreds of thousands (or more) in total denier. The drawing operation involves conveying the tow between a set of feed rolls and a set of drawing rolls (operating at a higher speed than the feed rolls) to increase the orientation of the nylon polymer within the filaments. Drawing is often combined with an annealing operation to increase the nylon crystallinity in the tow filaments before the tow is converted into staple fibers.

One of the advantages of nylon staple fibers is that they are readily blended with natural fibers, especially cotton (often referred to as short staple) and/or other synthetic fibers, to achieve the benefits derivable from such blends. It is to be. In particular, a particularly desirable form of nylon staple fiber has been used for blending with cotton to improve the durability and economy of fabrics made from yarns comprising blends of cotton and nylon. . It is disclosed that such nylon staple fibers are disclosed in Hebeler U.S. Pat. Nos. 3,044,250; 3,188,790; , the disclosure of which is incorporated herein by reference in its entirety). As described by Hebeler, the load-bearing capacity of nylon staple fibers is conveniently measured as the strength at 7% elongation (T7), the T7 parameter has long been accepted as a standard measurement, Reads easily on an Instron machine.

The Hebeler process for preparing nylon staple fibers involves the nylon spinning, tow forming, drawing, and converting operations described above. Subsequent improvements to the Hebeler process for preparing nylon staple fibers modified the nature of the tow drawing operation and added a specific type of annealing (or high temperature treatment) and subsequent cooling steps to the overall process. has been done by For example, Thompson in U.S. Pat. Nos. 5,093,195 and 5,011,645 discloses, for example, a nylon 6,6 polymer having a formic acid relative viscosity (RV) of 55 is spun into filaments and then drawn. into a staple fiber having a strength at break T of about 2.44 at a denier of about 6.8-6.9 per filament and a load-bearing capacity T7 of about 2.4-3.2. A cutting, nylon staple fiber preparation is disclosed. The Thompson patent further discloses that such nylon staple fibers are blended with cotton and formed into yarns of improved yarn strength. (Both of these Thompson patents are hereby incorporated by reference in their entireties.)

Nylon staple fibers prepared according to the Thompson technique are blended with NYCO yarns (generally at a 50:50 nylon/cotton ratio) and these yarns are used to prepare NYCO fabrics. Such NYCO fabrics (eg, woven fabrics) find application in combat uniforms and apparel. While such fabrics have generally proven satisfactory for military or other heavy-duty apparel, for example, military authorities have sought lighter weight, lower cost, and/or more There is a continuing need for improved fabrics that are comfortable yet are still durable or whose durability can be improved.

PCT/US2015/055333 discloses high strength or load bearing nylon yarns and yarns having a breaking strength of greater than 7.5 g/den and 7.5 g/den and/or a strength at 10% elongation of greater than 4.0 g/den; Disclosed are fabrics and articles of manufacture and methods of making them.

The desire and interest in adding pigments such as carbon black to fibers, particularly in military apparel, has been demonstrated. See, for example, US Pat. No. 5,830,572, US Pat. No. 7,008,694 and US Pat. No. 7,320,766.

In addition, denim and canvas fabrics, especially dark denim, especially black denim, are popular in the market but are known in the industry to have problems with fading or color fastness. For example, in the case of black denim, the color fades quickly after repeated washing/wear. It is also known that the addition of nylon as a blend with cotton or cellulosic fibers significantly improves the durability of the yarn and resulting fabric by improving abrasion resistance. The black dye used to dye black denim fabric only dyes nylon and is neither dark nor permanent on nylon fibres, when the dye is on cotton fibres.

However, any blend of nylon staple with cotton fibers or cellulose fibers requires high strength/high modulus.

Adding additives such as pigments to the polymer prior to melt spinning of the fiber has historically reduced fiber physical properties. For example, organic pigments tend to crosslink nylon, alter its viscosity, form spherulites that weaken the fiber, and increase draw tension and filament breakage. The more pigment added, the greater the strength loss. These reduced fiber properties have prevented or limited the mixing of colored nylon staples with cellulose fibers due to the resulting problem of reduced yarn and fabric strength.

For example, DuPont manufactured dyed nylon staples in the mid to late 1990's for use in automotive interiors. The resulting nylon staple product had a breaking strength of 5.5 grams/denier. The only end use identified at that time was yarn spun in 100% form for automotive/home interiors.

U.S. Pat. No. 5,290,850 discloses an improved process for melt spinning colored hexamethylene adipamide fibers from a melt blend of a polymer and a colored pigment, the polymer comprising:7. Random interpolyamides or block polymers having two different difunctional repeating amide-forming moieties other than the original forming hexamethylene exhibiting strengths greater than 5 grams/denier.

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

Addition of any inorganic or organic pigments or additives to the polymer during the melt spinning process usually reduces the resulting fiber strength. Fiber strength loss results in lower strength of the yarn and resulting fabric. We have found that adding additives to the nylon polymer prior to fiber formation and drawing the fibers under a steam-assisted/annealing process results in the production of additive-containing high strength/high modulus fibers. unexpectedly discovered that

Accordingly, one aspect of the present invention relates to nylon staple fibers comprising a nylon polymer and an additive. Nylon staple fibers with the additive of the present invention exhibit breaking strengths in excess of 6.5 g/den. In one non-limiting embodiment, the nylon staple fiber exhibits a strength at 10% elongation of greater than 3.0 g/den. Non-limiting examples of additives that may be included in these fibers are pigments and additives included for fire or flame (FR) resistance and/or ultraviolet (UV) protection.

Another aspect of the invention relates to yarn spun from nylon staple fibers. In a non-limiting one, the yarn further comprises at least one companion staple fiber. In one non-limiting embodiment, the yarn has a nylon content greater than 5%. In one non-limiting embodiment, the nylon content of the yarn is 30%. Super. In one non-limiting embodiment, the yarn has a nylon content greater than 50%. Such yarns are advantageously lightweight, comfortable, low cost and durable, and are therefore particularly suitable for use in, for example, military apparel, such as combat uniforms or other apparel for demanding applications. Suitable fabrics and other product articles can be manufactured.

Another aspect of the invention relates to an article of manufacture, at least a portion of which comprises 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 in a single color and/or exhibits a uniform dark shade.

In one non-limiting embodiment, the fabric exhibits improved UV lightfastness over the closest comparative fabric that does not contain such pigment-containing or additive components.

In one non-limiting embodiment, the fabric exhibits improved dye washfastness over the closest comparative fabric that does not contain such pigment-containing or additive components.

In one non-limiting embodiment, the fabric has a camouflage pattern. The fabric is typically constructed by using colored synthetic fibers such as polyamide 6,6 or nylon 6,6, although the fabric may be greige or uncolored fabric. However, if the fibers are colored, patterns can still occur on the colored fabric.

In one non-limiting embodiment, the fabric has NIR (near infrared) reflectance in the range of 600-900 nm and/or lower and flattened SWIR (short wavelength infrared) reflectance in the range of 900-2500 nm. Present. In addition, the fabric increases the infrared (IR) reflectance curve separation between individual colors used on fabric printed in the SWIR spectrum, providing further inhibition and improved camouflage effectiveness for night vision goggle surveillance. do.

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

In one non-limiting embodiment, the fabric exhibits an improved electric arc rating over the closest comparative fabric that does not contain such pigment-containing or additive components.

In one non-limiting embodiment, the article of manufacture is denim fabric. In one non-limiting embodiment, the denim fabric is overdyed with a color similar to the pigment contained in the nylon staple fibers. Additionally, when the fibers are black and the fabric is printed dark, a more evenly dyed product is obtained, although the black fibers minimize or eliminate the appearance of white fibers showing through the fabric. This is because it acts to

In another non-limiting embodiment, the article of manufacture is a nonwoven composite. End uses for such composites include industrial (felt/lining/filtration/insulation), apparel (including liner fabric), footwear, bags/pack hard gear, FR (with chemical treatments or proprietary FR fiber technology). durable and semi-durable (disposable or semi-disposable) garments or PPE including, but not limited to, biochemical, or other specialty protective wear.

Yet another aspect of the present invention relates to a method for producing high strength or high load bearing colored nylon staple fibers. The method of the present invention involves melt spinning a nylon polymer with pigment into filaments, then uniformly quenching the filaments, and forming a tow from a number of these quenched filaments. The tow is then stretched in the presence of steam. The drawn tow is then annealed and the resulting drawn and annealed tow is converted into staple fiber. In one non-limiting embodiment, annealing is performed under tension. Nylon staple fibers produced according to this method have breaking strengths in excess of 6.5 g/den. In one non-limiting embodiment, nylon staple fibers prepared according to this method have a strength at 10% elongation of greater than 3.0 g/den.

According to the present disclosure, high-strength or high-load-bearing nylon staple fibers having additives that exhibit a breaking strength of greater than 6.5 g/den and/or a strength at 10% elongation of greater than 3.0 g/den, at least in part thereof Yarns, fabrics, and other articles of manufacture prepared from fibers of and methods for their manufacture are provided.

Non-limiting examples of additives included in nylon staple fibers are pigments, additives to 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 to about 50,000 ppm. In one non-limiting embodiment, the pigment is carbon black. Further examples of suitable pigments are ultramarine violet, sulfur-containing sodium and aluminum silicates; humpurple, _BaCuSi2O6 ; cobalt violet, cobaltic acid _{orthophosphate} ; manganese violet, _{NH4MnP2O . 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 (II) Tin; Egyptian Blue, _{( CaCuSi4O10 )} ; Ham Blue, _BaCuSi4O10 ; Azurite, ( _Cu3 ( _CO3 ) ₂ ( _OH2 )); Prussian Blue, Hexacyanoferrate, Immin Blue, (Yln _{1-x Mn x} O ₃ ); cadmium green, mixture of CdS and Cr ₂ O ₃ ; chromium green, chromium oxide; Viridian, hydrated chromium oxide _; Paris green, Cu( _{C2H2O2 ) 2.3Cu ( AsO2} ) ₂ ); Scheele green, _CuHAsO3 ; _typically with cuprid acetate and/or _malachite . Verdigris; Verona green, (K[(Al, Fe ^III ), (Fe ^II , Mg] (AlSi ₃ , Si ₄ ) 0 ₁₀ (OH) 2); male yellow, (As ₂ S ₃ ); primrose yellow - , ( _BiVO4 ); cadmium yellow, _CdS ; chrome yellow, _{PbCrO4 ;} cobalt yellow, ( _K3Co ( _NO2 ) ₆ ); yellow ocher, ( _Fe2O3.H2O ); titanium yellow; Nitin, _SnS2 ; Cadmium Orange, Cadmium Selenide Sulfide, Chromium Orange, ( _{PbCrO4+PbO); Cockstone, AS4S4 , Cadmium} Red, _CdSe ; Indian Red; Red Ocher, _Fe2O3 ; Burnt Sienna; Vermillion, HgS; Raw Umber _{, Fe2O3 + MnO2} + _nH2O +Si+ _{AlO3 ;} Raw Sienna; Ivory Black; Vine Black; Lamp Black; Lac, Ti ₂ O ₃ , Antimony White, Sb ₂ O ₃ , Barium Sulfate, Litpon, BaSO ₄ . ZnS; Kremnitz White, (( _PbCO3 ) _2.Pb (OH) ₂ ); titanium dioxide, _TiO2 ; and zinc oxide, ZnO.

Also provided by the present disclosure is a nonwoven composite comprising high strength fibers and cellulosic or regenerated synthetic or natural fibers.

As used herein, the terms "durable" and "durable" have high grip and tear strength and resistance to abrasion suitable for the intended end use of such fabrics. , refers to the tendency of fabrics to be characterized by the retention of such desirable properties for a suitable length of time after the fabric is put into use.

As used herein, the terms "blend" or "blended," when referring to spun yarns, mean a mixture of at least two types of fibers, a mixture comprising individual fibers of each type of fiber. The fibers are substantially thoroughly mixed with other types of individual fibers to provide a substantially homogeneous mixture of fibers having sufficient entanglement to maintain integrity in further processing and use. .

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

All numerical values recited herein are understood to be modified by the term "about."

Some embodiments are based on the preparation of improved nylon staple fibers with additives having certain properties, and fabrics woven from such yarns, these improved with additives. The nylon staple fibers are blended with at least one other fiber. Other fibers include cellulose derivatives such as cotton, modified cellulose derivatives such as fire resistant (FR) treated cellulose, animal fibers such as polyester, rayon, 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. 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 weak fibers such as cotton and wool.

Specific properties of the nylon staple fibers with additives prepared and used herein include fiber denier defined in terms of fiber strength at 7% and 10% elongation, fiber strength, and fiber load bearing capacity. mentioned.

Realization of the desired nylon staple fibers with additives herein is a staple fiber of nylon polymer filaments and tows having specific selected properties and processed using specific selected processing operations and conditions. Based on use in manufacturing. Specifically, we herein demonstrate that the introduction of steam and/or the introduction of tension between the feed and draw module during annealing during the manufacture of nylon staple fibers with additives is such It has been found that the decrease in strength associated with the addition of such fiber additives is significantly inhibited or prevented. In one non-limiting embodiment of the invention, steam is introduced into the process by adding a steam chamber between the feed and the draw module, which allows excess water to be removed prior to annealing. . Without wishing to be bound by any particular theory, the steam chamber applies sufficient heat/steam to reduce the draw force of the nylon, causing the draw to be placed in the steam chamber, over the feed roll exit or It is believed to help avoid placement at the feed roll exit. Steam can be controlled by pressure.

The nylon polymer itself used for spinning the nylon filaments of the present invention can be produced by conventional methods. Suitable nylon polymers for use in the processes and filaments of some embodiments include synthetic melt-spinnable or melt-spun polymers. Such nylon polymers can include polyamide homopolymers, copolymers, and mixtures thereof that are predominantly aliphatic, i.e., less than 85% of the amide linkages of the polymer are attached to two aromatic rings. Widely used polyamide polymers such as poly(hexamethyleneadipamide), which is nylon 6,6, and poly(ε-caproamide), which is nylon 6, and copolymers thereof and mixtures thereof, but some It can be used according to embodiments. Other polyamide polymers that may be used to advantage are nylon 12, nylon 4,6, nylon 6,10, nylon 6,12, nylon 12,12, and copolymers and mixtures thereof. Examples of polyamides and copolyamides that can be used in the processes, fibers, yarns and fabrics of some embodiments are U.S. Pat. (Cofer et al., respectively), and the polyamide polymer mixture is described by Gutmann in Chemical Fibers International, pp. 418-420, vol. 46, Dec. 1996. All of these publications are incorporated herein by reference.

In one non-limiting embodiment, the polymer may further comprise a monomeric salt of sulfonated isophthalic acid (SIPA) or monomeric 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 preparation of nylon staple fibers are conventionally mixed with suitable monomers, catalysts, antioxidants, and other additives including, but not limited to, plasticizers, matting agents, pigments, dyes, light stabilizers, heat stabilizers, antistatic agents to reduce static, additives to modify dye capacity, agents to modify surface tension, etc.) are prepared by reacting . Polymerizations are typically carried out in continuous polymerizers or batch autoclaves. The molten polymer thus produced is typically introduced into a spin pack, extruded through a suitable spinneret to form filaments, quenched, and then for final processing into nylon staple fibers. formed into a tow for As used herein, a spin 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 sandwiched between the former two components. . The filter holder has a central recess therein. A lid and recess in the filter holder cooperate to define a sealed pocket in which polymeric filter media such as sand is received. Channels are provided in the interior of the pack for a flow of molten polymer supplied by a pump or extruder to move through the pack and ultimately through the spinneret plate. The spinneret plate has an array of small precision holes extending through it that transfer the polymer to the underside of the puck. The mouths of the holes form an array of orifices on the lower surface of the spinneret plate and this surface defines the top of the quench zone. The polymer exiting these orifices is in filament form and is then directed downward through a quench zone.

The extent of polymerization carried out in a continuous polymerizer or batch autoclave can generally be quantified by a parameter known as 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 taken as an indirect measure of nylon polymer molecular weight. For the purposes of this specification, an increase in nylon polymer RV is considered synonymous with an increase in nylon polymer molecular weight.

As the nylon molecular weight increases, the increased viscosity of the nylon polymer makes it more difficult to process. Thus, continuous polymerizers or batch autoclaves are typically operated to provide nylon polymers for final processing into staple fibers, where the nylon polymers have RV values of about 60 or less.

It has been found that for some purposes it can be advantageous to provide a higher molecular weight nylon polymer, i. ing. For example, high RV nylon polymers of this type are known to have improved resistance to flex abrasion and chemical degradation. Such high RV nylon polymers are therefore particularly suitable for spinning into nylon staple fibers that can be advantageously used in the preparation of papermaking felts. Procedures and equipment for making high RV nylon polymers and staple fibers therefrom are described in U.S. Pat. Nos. 5,236,652 (Kidder) and U.S. Pat. 6,627,129 and 6,814,939 (Schwinn and West). All of these patents are incorporated herein by reference in their entirety.

According to some embodiments, nylon polymers prepared from nylon polymers having RV values that generally broadly match, or in some cases are higher than, RV values obtained via polymerization in continuous polymerizers or batch autoclaves. When staple fibers with additives are treated in the presence of steam and following spinning, quenching, feeding and drawing with the annealing procedures described herein, fiber breakage is reduced compared to the standard product or the improvements described above. It was discovered to unexpectedly exhibit increased strength and increased strength at 10% elongation. Blending such nylon staple fibers with improved strength additives with one or more other fibers, such as cotton staple fibers, can provide improved strength as well as lower weight textile yarns. can. Fabrics, such as NYCO fabrics, woven from such yarns may have durability, optional weight savings, improved comfort and/or potentially lower cost, as well as selected additive colors, UV protection, , or exhibit the advantages previously described herein with respect to FR resistance.

According to the staple fiber preparation process herein, the additive-bearing nylon polymer that is melt-spun and quenched through one or more spin pack spinnerets into tow-forming filaments is 55-100 to 46-65,50 It has RV values ranging from 45-100, including ˜60, and 65-100. Such RV-characteristic nylon polymers can be prepared, for example, using a melt-blending polyamide concentration procedure such as the process disclosed in the aforementioned Kidder '652 patent. Kidder discloses certain embodiments of adding a catalyst for the purpose of increasing the relative viscosity (RV) of formic acid. Higher RV nylon polymers available for melting and spinning, such as nylons with an RV of 65-100, can also be provided by solid state polymerization (SPP) processes, where nylon polymer flakes or granules are Adjusted to increase RV to desired extent. Such solid state polymerization (SPP) procedures are well known and are disclosed in greater detail in the aforementioned Schwinn/West '390, '694, '129 and '939 patents.

A nylon polymer material with additives having the requisite RV properties specified herein is fed into the spin pack via, for example, a twin-screw melter. In one non-limiting embodiment, a volumetric or gravimetric feeder is used for additive addition. Spin packs are spun by extruding a nylon polymer with additives into a large number of filaments through one or more spinnerets. For the purposes of this specification, the term "filament" refers to a relatively flexible, macroscopically homogeneous body having a high length-to-width ratio across its cross-sectional area perpendicular to its length. Defined. The filament cross-section may be of any shape, but is typically circular. The term "fiber" may also be used interchangeably with the term "filament" herein.

Each individual spinneret location may contain 100 to 1950 filaments in a small area of 9 inches by 7 inches (22.9 cm by 17.8 cm). A spin pack machine may include 1 to 96 positions, each of which provides filament bundles that are ultimately combined into a single tow band for drawing/downstream processing on other tow bands.

After exiting the spinneret, the molten filaments extruded through each spinneret typically pass through a quench zone using various quench conditions and configurations to solidify the molten polymer filaments with additives; They can be made suitable for collection together. Quenching is most commonly directed to, over, with, around, and through the filament bundle extruded from each spinneret location in the spin pack into the quench zone by a cooling gas, For example, by passing air through it.

One suitable quenching configuration is cross-flow quenching, in which a cooling gas, such as air, is forced into the quench zone in a direction substantially perpendicular to the direction in which the extruded filaments travel through the quench zone. be. Cross-flow quench configurations are described, among other quench configurations, in U.S. Pat. Nos. 090,485, 6,881,047 and 6,926,854, the teachings of which are incorporated herein by reference in their entireties.

In one non-limiting embodiment of the staple fiber preparation process herein, additive-bearing extruded nylon filaments used to ultimately form the desired additive-bearing nylon staple fibers are spun and Uniformity of location and quench conditions as described in quenched and published U.S. Patent Application Nos. 2011/0177737 and 2011/0177738, which are hereby incorporated by reference in their entirety. Formed in the tow in both sexes.

The quenched spun filaments can then be combined into one or more tows. Such tows formed from filaments from one or more spinnerets are then subjected to a two-stage continuous operation in which the tows are drawn and annealed in the presence of steam.

Tow drawing generally occurs primarily in an initial or first drawing stage or zone, with the tow band passing between a set of feed rolls and a set of draw rolls (operating at a higher speed). to increase the crystalline orientation of the filaments within the tow. The extent to which the tow is stretched can be quantified by specifying a stretch ratio, which is the ratio of the higher peripheral speed of the stretch rolls to the lower peripheral speed of the feed rolls. The effective draw ratio is calculated by multiplying the first draw ratio and the second draw ratio.

The first draw stage or zone may include several sets of feed rolls and draw rolls, as well as other tow guides and tension rolls such as snub pins. The draw roll surface may be made of metal, such as chromium, or ceramic. Ceramic draw roll surfaces have been found to be particularly advantageous in allowing the use of relatively high draw ratios designated for use in connection with the staple fiber preparation process herein. Ceramic rolls improve roll life and also provide a surface that is less prone to lapping. Articles appearing in the International Fiber Journal (International Fiber Journal, 17, 1, 2 2002: "Textile and Bearing Technology for Separator Rolls", Zeitz and el.), as well as U.S. Patent No. 4,794, incorporated herein by reference. 680 also discloses the use of ceramic rolls to improve roll life and reduce fiber adhesion to the roll surface.

Although the maximum degree of drawing of a tow of filaments herein occurs in the initial or first drawing stage or zone, additional drawing of a portion of the tow is generally performed in a second or annealing step as described below. It can also be done in stages or zones. The total amount of drawing to which the filament tows herein are subjected takes into account the drawing that occurs in both the first initial drawing stage or zone and the second zone or stage in which annealing and some additional drawing occur simultaneously. can be quantified by specifying the total effective draw ratio.

In the process of some embodiments, the nylon filament tow with additive is subjected to a total effective draw ratio of 2.3 to 5.0, including 3.0 to 4.0. In one embodiment where the tow has generally low denier per filament, the total effective draw ratio may range from 3.12 to 3.40. In another embodiment, the denier per filament of the tow is generally higher and the total effective draw ratio may range from 3.5 to 4.0.

In the process herein, as noted above, most of the tow drawing occurs in the first or early drawing stages or zones. Specifically, 85% to 97.5%, including 92% to 97%, of the total amount of stretch imparted to the tow occurs in the first or initial stretch stage or zone. The first or early stage drawing operation generally occurs at whatever temperature the filaments are at as they pass from the quench zone of the melt spinning operation. In most cases, the stretching temperature for this first stage is in the range of 80°C to 125°C.

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

From the first or initial drawing stage or zone, the partially drawn tow is passed to a second annealing stage and drawing stage or zone where the tow is simultaneously heated and further drawn. Heating the tow for annealing serves to increase the crystallinity of the nylon polymer of the filaments. In this second annealing and drawing stage or zone, the filaments of the tow are 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 during this annealing and drawing stage is controlled by contacting the tow with a steam heated metal plate positioned between the first stage drawing and the second stage drawing and annealing operations. can be achieved by letting In the present invention, annealing/oven drying under tension helps remove excess moisture obtained during steam drawing.

After the annealing and stretching stages of the process herein, the stretched and annealed tow is cooled to a temperature below 80°C, such as below 75°C. Throughout the drawing, annealing and cooling operations described herein, the tow is maintained under controlled tension and is therefore not allowed to relax.

After drawing in the presence of steam and annealing/oven drying under tension, the multifilament tow is converted into staple fibers with additives by any conventional method, for example using a staple cutter. Staple fibers with additives formed from tow range in length from 2 to 13 cm (0.79 to 5.12 inches). For example, staple fibers with additives can range from 2-12 cm (0.79-4.72 inches), 2-12.7 cm (0.79-5.0 inches), or 5-10 cm. Staple fibers with additives herein may optionally be crimped.

High strength nylon staple fibers with additives formed according to the processes herein are generally provided as a collection of fibers, for example, a collection of fibers having a denier per fiber of 1.0 to 3.0. . If staple fibers with a denier per fiber of 1.6-1.8 are prepared, the process herein uses 3.12-3.40 to provide the required load-bearing capacity of the staple fiber. , for example a total effective draw ratio of 3.15 to 3.30 can be used. If staple fibers are prepared with a denier per fiber of 2.5-3.0 or 2.3-2.7, then 3.5-4. A total effective draw ratio of 0, or 3.74 to 3.90 should be used in the process herein.

Using this process and then using standard annealing rolls to anneal the fiber with additive at 180° C., significantly higher strength fiber with additive having strength greater than 6.5 g/den manufactured.

In one non-limiting embodiment of the present invention, an additive-bearing nylon staple fiber is disclosed having a strength at 10% elongation of at least 3.0 g/den.

A fiber with the above properties and the additional advantages of the present invention of additives in the fiber such as pigments, UV protectants, and FR-resistors can be used as an alternative to significantly reduce fabric manufacturing costs while still meeting existing fabric specifications. Lower blend ratios can be used or spun into yarn using conventional spinning systems. This fiber can be used to significantly reduce yarn spinning and finished fabric costs by allowing the use of lower nylon blend levels and/or alternative spinning systems while maintaining fabric properties. can be done.

Nylon staple fibers with 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 herein include those made of natural cellulosic fibers such as cotton, flax, hemp, jute and/or ramie. Suitable methods for intimately blending these fibers include bulk mechanical blending of staple fibers before carding, bulk mechanical blending of staple fibers before and during carding, or after carding and At least two passes through a draw frame blend of staple fibers may be included prior to yarn spinning.

According to one non-limiting embodiment, high load bearing nylon staple fibers with additives described herein may be blended with cotton staple fibers and spun into textile yarns. Such yarns are conventionally spun using commonly known short and long staple spinning methods including ring spinning, air jet or vortex spinning, open end spinning, or friction spinning. Can be spun. When the yarn blend includes cotton, the resulting textile yarn generally has a weight ratio of cotton fibers to nylon fibers of 10:90 to 90:10, including 30:70 to 70:30, often cotton:nylon. The weight ratio is 50:50. It is well known in the art that nominal variations in fiber content, such as 52:48, are also considered 50:50 blends.

The nylon/cotton (NYCO) yarns of some embodiments are prepared using conventional methods to prepare NYCO woven fabrics with particularly desirable properties for use in military apparel or apparel for other demanding applications. can be used in Thus, such yarns may be woven into 2x1 or 3x1 twill NYCO fabrics. Spun NYCO yarns and 3×1 twill fabrics, including such yarns, are generally described and illustrated in US Pat. No. 4,920,000 (Green), incorporated herein by reference.

Of course, NYCO woven fabrics include both warp and weft (filler) yarns. Woven fabrics of some embodiments herein are those having NYCO woven yarns woven in at least one, and optionally both, of these directions. In one embodiment, the particularly desirable durability and comfort fabrics herein have yarns woven in the weft (fill) direction comprising nylon staple fibers with the additives herein, warp comprising nylon staple fibers having an additive of

Woven fabrics of some embodiments made with yarns comprising high load bearing nylon staple fibers with the additives herein use less nylon staple fibers than conventional NYCO fabrics, Many of the desirable properties of such conventional NYCO fabrics can be retained. Accordingly, such fabrics can be made relatively lightweight and low cost, yet desirably durable. Alternatively, such fabrics have the additives herein compared to the nylon fiber content of nylon staple fibers with the additives herein and conventional NYCO fabrics having such fabrics. It can be made using nylon staple fibers.

In one non-limiting embodiment, the nylon staple fibers of the present invention with pigment additives are used to make articles of manufacture such as denim fabrics. Currently, black dyed 100% cotton denim fabric has problems of fading and abrasion after repeated washings. Non-pigmented high-strength nylon staples can be added to improve fabric durability and strength, but the problem of fading remains. The addition of colored high strength nylon staples of the present invention with additives such as carbon black reduces loss of black appearance and improves wear life. Alternative pigments for colors such as blue, green, and tan can also be used, as will be appreciated by those skilled in the art upon reading this disclosure. In this non-limiting embodiment, for example, colored fibers having 1-5% by weight of carbon black or denim blue coloration can be used in denim to reduce fabric fading issues and improve durability. . Incorporation of these fibers into fabrics is particularly useful in manufactured articles that are dyed in single colors and/or where improved uniformity in dyeing, such as dark shades, is desired.

In some embodiments, the denim fabric may be overdyed with colors similar to the pigments contained in the nylon staple fibers. Camouflage patterned fabrics may also be made from nylon staple fibers using the additive of the present invention.

Such fabrics are expected to exhibit improved dye washfastness.

Additionally, the addition of carbon black to fibers or fabrics as a topical treatment improves uniform/wearer concealment when viewed through night vision goggles using near-infrared (NIR) and short-wave infrared (SWIR) technology. known to improve.

Accordingly, in another non-limiting embodiment, nylon staple-colored fibers of the present invention having carbon black in the range of 10-1000 ppm are used to produce uniforms containing the fibers when viewed with SWIR/IR night vision goggles. Confidentiality of articles of manufacture such as can be improved. In one non-limiting embodiment, the incorporation of colored nylon staple fibers of the present invention containing conventional dyes can produce visible spectrum hues without the need for pre- or post-treatment or use of metallization or specialty pigment formulations. NIR reflectance in the range of 60-900 nm can be reduced without significantly changing , thus improving zero inhibition and camouflage effectiveness for night vision goggle surveillance.

In another non-limiting embodiment, the incorporation of the colored nylon staple fibers of the present invention with conventional dyes can be used for pre-treatments of metallized or specialty pigment formulations required for monochromatic and printed camouflage NYCO fabrics or The short wavelength infrared reflectance (SWIR) in the 900-2500 nm range can be made lower and flatter in the 900-2500 nm range without the need for post-treatment or use, significantly changing the shading in the visible spectrum. thus improving the effectiveness of the blocking and camouflage for night vision goggle surveillance. In yet another non-limiting embodiment, the incorporation of colored nylon staple fibers of the present invention containing conventional dyes can be achieved within SWIR without the need for pre- or post-treatment or use of metallization or special pigment formulations. can increase the level of separation between printed colors in the 90-2500 nm range, thus improving zero inhibition and camouflage effectiveness for night vision goggle surveillance. Such fabrics of the present invention are also expected to exhibit improved electric arc ratings.

In another non-limiting embodiment, incorporation with additives that provide UV protection, or additives that provide FR resistance to articles of manufacture such as fabrics, provides improved UV fastness and/or flame retardancy. Bring.

The invention also relates to nonwoven composites comprising the high strength fibers of the invention. High strength fibers can be combined with various cellulosic or regenerated synthetic or natural fiber technologies. In one embodiment, high strength fibers are combined with recycled denim. End uses for nonwoven composites include: industrial (felt/lining/filtration/insulation), apparel (including liner fabrics), footwear, bags/pack hard gear, FR (combined with chemical treatments or proprietary FR fiber technology) durable and semi-durable (disposable or semi-disposable) garments or PPE including, but not limited to, biochemical, or other specialty protective wear.

At least a portion of the yarns on the top surface or at least the yarns on the bottom surface that have fibers with permanently modified cross-sections and are melt fused together, as will be understood by one of ordinary skill in the art upon reading this disclosure. Alternative methods and devices are available for producing a portion and their use is encompassed by the present invention.

All patents, patent applications, testing procedures, priority documents, articles, publications, manuals, and other documents cited herein are to the extent such disclosures do not contradict the present invention, and such incorporation is fully incorporated by reference for all jurisdictions where

TEST METHODS AND EXAMPLES The following test methods and examples demonstrate the present disclosure and its ability to use. As the invention is capable of other and different embodiments, its several details are capable of modifications in various obvious respects, all without departing from the scope and spirit of this disclosure. Therefore, the test methods and examples should be considered non-limiting, exemplary in nature.

Nylon Polymer Relative Viscosity As used herein, the formic acid RV of nylon materials refers to the ratio of solution and solvent viscosities measured with a capillary viscometer at 25°C. The solvent is formic acid containing 10% by weight water. The solution is 8.4 weight percent nylon polymer dissolved in a solvent. This test is based on ASTM standard test method D789. The formate RV is determined on the spun filaments before or after drawing and is sometimes referred to as the spin fiber formate RV.

Instron Measurements of Staple Fibers All Instron measurements of staple fibers herein are made by using staple fiber clamps with due care to make an average of the measurements over at least 10 fibers. , is performed for a single staple fiber. Generally, at least three sets of measurements (10 fibers each) are averaged together to provide the value of the determined parameter.

Filament Denier Denier is the linear density of a filament expressed as weight in grams of 9000 meters of filament. Denier can be measured on a Vibroscope from Texttechno, Munich, Germany. Denier time (10/9) is equal to decitex (dtex). Denier per filament can be measured gravimetrically according to ASTM standard test method D1577. A Favimat machine with vibration-based linear density measurements, such as those used in the Vibroscope, can be used to determine the DPF or denier per filament of individual fibers and is equivalent to ASTM D1577.

Breaking Strength Breaking strength (T) is the maximum or breaking force of a filament expressed as force per unit cross-sectional area. Strength can be measured with an Instron Model 1130 available from Instron (Canton, MA) and is reported as grams per denier (grams/dtex). Filament strength at break (and elongation at break) can be measured according to ASTM D885.

Filament Strength at 7% and 10% Elongation Filament strength at 7% elongation (T7) is the force applied to a filament to achieve 7% elongation divided by the filament denier. T7 can be determined according to ASTM D3822. Strength at 10% elongation can be run on a Favimat comparable to ASTM D3822.

Yarn Strength The strength of the spun nylon/cotton yarns herein can be quantified via the Lea Product value or yarn break strength. Lea Product and skein breaking strength are conventional measures of the average strength of textile yarns and can be determined according to ASTM D1578. Lea Product values are reported in pounds of force. Breaking strength is reported in units of cN/tex.

Fabric Weight The fabric weight or basis weight of woven fabrics herein is defined by weighing a fabric sample of known area according to the standard test method procedures of ASTM D3776 and measuring the weight or basis weight in terms of grams/ ^m2 or oz/ ^yd2 . It can be determined by calculating basis weight.

Fabric Grip Strength Fabric grip strength can be measured according to ASTM D5034. Grip strength measurements are reported in pounds force in both the machine direction and the fill direction.

Fabric Tear Strength - Elmendorf Fabric tear strength can be measured according to ASTM D1424 entitled Standard Test Method for Tearing Strength of Fabrics by Falling - Pendulum Type (Elmendorf) Apparatus. Grip strength measurements are reported in pounds force in both the machine direction and the fill direction.

Color Fastness to Washing - AATCC Test Method 61
AATCC61 is used to assess the color fastness to washing of fabrics expected to withstand frequent laundering. The specimen is attached to the multifiber swatch, the stainless steel ball is loaded into the stainless steel canister, and the polishing is repeated. The canister is then loaded into the machine and the 45 minute test begins. After washing, the specimens are dried, conditioned and evaluated on both a gray scale for color change and a gray scale for staining. Fabric dimensional change after washing is also tested and applied for evaluation according to AATCC Test Method 135.

Color Fastness to Light - AATCC Test Method 16
This test method provides the general principles and procedures currently used to determine the color fastness to light of textile materials. The test options described are applicable to all types of textile materials and are applicable to colorants, finishes and treatments applied to textile materials.
The test options included are
1-Enclosed carbon arc lamp, continuous light 2-Enclosed carbon arc lamp, alternating light/dark 3-Xenon arc lamp, continuous light, black panel option 4-Xenon arc lamp, alternating light/dark 5-Xenon arc lamp, continuous light , black standard option 6 - sunlight behind glass

Colorimetric Analysis N1R and SW1R analyzes are performed using any commercially available color spectrophotometer such as the 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.

Claims (6)

1. A method for producing high strength or load bearing nylon staple fibers having an additive comprising:
melt spinning the nylon polymer and additives into filaments;
uniformly quenching the filaments;
forming a tow from a plurality of these quenched filaments;
passing the tow from a series of feed rolls to a series of draw rolls while introducing steam into the tow;
stretching the steamed tow;
annealing the stretched tow;
converting the resulting drawn and annealed tow into staple fibers ;
wherein the nylon staple fibers have a breaking strength of greater than 6.5 g/den and a strength at 10% elongation of greater than 3.0 g/den;
The method, wherein said additive is selected from pigments, additives for ultraviolet (UV) protection, or additives for flame or fire (FR) resistance. 2. The method of claim 1 , wherein annealing is performed under tension. The method of claim 1, wherein said additive is a pigment present in an amount from 10 ppm to 50,000 ppm. 2. The method of claim 1, wherein the nylon polymer is selected from the group consisting of nylon 6,6, nylon 6, and combinations thereof. 2. The method of claim 1, wherein the nylon polymer further comprises a monomeric salt of sulfonated isophthalic acid (SIPA) in an amount of 0.04-4% by weight of the nylon polymer. 2. The method of claim 1, wherein the nylon polymer further comprises the monomer methylpentamethylenediamine (MPMD) in an amount of 0.04-4% by weight of the nylon polymer.