BR112015016987B1 - Article, method for making an article and elastic fabric - Google Patents

Abstract

ARTICLES, METHOD FOR MANUFACTURING AN ARTICLE AND ELASTIC FABRIC Articles and methods are included in this document, including a central spun yarn. The central spun yarn includes a sheath of hard fibers and two sets of elastic fibers, wherein the sets of elastic fibers have different properties. The properties may differ in one or more ways such as having a different denier, composition, or confection. One or both of the sets of elastic fibers may be pre-covered.

Description

FIELD OF THE INVENTION

[001] This invention relates to the manufacture of yarns and fabrics of elastic compounds. It is specifically about fabrics and methods, including two sets of core elastic fibers within a yarn.

BACKGROUND OF THE INVENTION

[002] Elastic fabrics with elastic composite yarn have been on the market for a long time. Fabric and garment manufacturers generally know how to make fabrics to the quality parameters to obtain fabrics acceptable to consumers. In today's commercially available fabrics, only one elastic fiber system exists within the yarns and fabrics. An elastic fiber provides dual functions: stretch and recovery. It is difficult to obtain fabrics that have easy stretch, high recovery and low shrinkage performance.

[003] Easy stretch is an important feature for comfort garments. For garments with greater comfort, the fabric can be stretched easily when the garment is placed on the human body and movement. They have low pressure exerted on the body by clothing. The garment can be cut to achieve a more streamlined appearance and can conform better to the body while still maintaining comfort for the wearer on the move. Such performance can be achieved through the fabric's low modulus of elasticity minimizing the garment's resistance to the demands of the body in motion.

[004] However, for fabric with low modulus of elasticity, a typical quality issue is that the fabric cannot be quickly regain its original size and shape after the fabrics are stretched further in some parts of the body, such as in knee, buttocks and waist, particularly for fabrics with a high level of stretch. Normally, fabric has low resilience when the modulus of elasticity is low. Consumers see flaccid and drooping issues after long wear and tear.

[005] In contrast, in order to obtain tissue with good recovery, extra contraction force is needed within the tissues. Higher content or more powerful elastic fiber can be added to fabrics. However, these tissues have superior modulus of extension and restricted superior strength. Consumers complain of high clothing pressures and uncomfortable restraint during wear and movement. At the same time, the fabric has a lower dimension of stability. Heat setting is a necessary processing to control fabric shrinkage. Clothing comfort and freedom of movement are compromised by the fabric's shape recovery and retention function. Fabrics having easy stretch, low shrinkage performance and high recovery are still desired.

[006] For many years, elastic yarn compounds are well known. For example, by US patent numbers 4470250, 4998403, 7134265, 6848151, elastomeric fibers such as elastane have been covered with relatively inelastic fibers to acceptably facilitate processing for knitting or weaving and to provide elastic yarn compounds with acceptable characteristics for various end-use fabrics. In the U.S. patent application US2008/0268734A1 and US 2008/0318485A1, a rigid filament is used, along with elastic filaments, as the core spun yarn within the core.

[007] Therefore, there is a need to produce stretch fabrics, which have easy stretching, simple process, low shrinkage, garment-friendly making, and excellent recovery power and low rise.

BRIEF DESCRIPTION OF THE INVENTION

[008] One aspect includes methods for making composite yarns with two sets of different elastic core fibers, referred to as a double elastic yarn composite. Also included are the composites of double elastic yarns and the stretching of fabrics and garments made from these yarns.

[009] According to the first embodiment of the method, two sets of elastic fibers with different properties and one hard fiber are covered together to form a composite yarn, in which the two sets of elastic fibers are stretched to different confections of their length. original during the wire covering process. The elastic fiber can be uncoated spandex yarn from 11 to 560 dtex, and the hard fiber with a yarn count from 10 to 900dtex. A suitable stiff yarn is cotton. Core elastic fiber I and core elastic fiber II are selected independently of an elastomeric or non-elastomeric fiber.

[010] According to a second embodiment of the method, two sets of elastic fibers (central elastic fiber I and central elastic fiber II) with different properties and a hard fiber are covered together to form a yarn composite, where the two sets of elastic fibers have different

[011] polymer compositions and with different stress deformation behaviors. The elastic fibers can be uncoated spandex yarn from 11 to 560 dtex, and the hard fiber with a yarn count from 10 to 900dtex. A suitable stiff yarn is cotton.

[012] According to a third embodiment of the method, two sets of different elastic core fibers (core elastic fiber I and core elastic fiber II) and a hard fiber are covered together to form a yarn composite, in which at least one set of central elastic fibers is pre-covered with elastic yarn.

[013] Another set of elastic core yarns can be spandex without covering or pre-covered elastic yarn. Spandex yarn without denier coverage is 11 to 560 dtex and hard fiber with a yarn count of 10 to 900 dtex. A suitable stiff yarn is cotton.

[014] According to a fourth embodiment of the method, two sets of different elastic core fibers and a hard fiber are covered together to form a composite yarn, in which at least one core elastic fiber is non-elastomeric stretch fiber. Another set of core elastic yarns may be uncoated elastomeric, such as spandex. Spandex yarn without denier coverage is 11 to 560 dtex and hard fiber with a yarn count of 10 to 900 dtex. A suitable stiff yarn is cotton.

[015] A fabric is made using double elastic yarn, produced by one of the following alternative methods. Double elastic yarn is used in at least one direction of the fabric. Any shape of fabrics can be used, including woven fabrics, circular knits, warp knits and narrow fabrics. Additional processing may include washing, bleaching, dyeing, drying, sanforizing, singeing, sizing, mercerizing, and any combination of such measures. The stretch fabric produced can be formed into a garment.

BRIEF DESCRIPTION OF THE FIGURES

[016] The detailed description will refer to the following drawings, in which the numbers refer to similar elements and in which:

[017] FIG. 1 is an illustration of center spun yarns with two center elastics.

[018] Fig. 2 is a schematic depiction of an apparatus turning the hub with two sewing devices for the two elastic fibers of their own.

[019] Fig. 3 is a schematic depiction of an apparatus turning the hub with two weighted roller cooking devices.

[020] Fig. 4 is a schematic depiction of an apparatus turning the hub with two sewing devices for an uncovered elastic fiber and a pre-covered elastic yarn.

DETAILED DESCRIPTION OF THE INVENTION

[021] Elastomeric fibers are commonly used to provide stretch and elastic recovery in woven fabrics and garments. "Elastomeric fibers" are a continuous filament (optionally a transformed multifilament) or a plurality of filaments, free of diluents, that have an elongation at break greater than 100% independent of any crimp. An elastomeric fiber when (1) extended up to twice its length; (2) held for one minute; and (3) released, retracts to less than 1.5 times its original length within one minute of being released. As used in the text of this specification, "elastomeric fibers" means at least one polymeric fiber or filament. Such elastomeric fibers include, but are not limited to, rubber filament, bi-constituent and elastoester filament, lastol and spandex.

[022] "Spandex" is a filament manufactured in which the filament-forming substance is a long-chain synthetic polymer composed of at least 85% by weight segmented polyurethane.

[023] "Elastoester" is a filament made in which the fiber-forming substance is a long-chain synthetic polymer composed of at least 50% by weight of aliphatic polyether and at least 35% by weight of polyester.

[024] "Biconstituent Filament" means a continuous filament or fiber including at least two polymers adhered to each other along the length of the filament, each polymer being in a different generic class, e.g. a polyetheramide elastomer core and a polyamide sheath with lobes or wings.

[025] "Lastol" is a cross-linked synthetic polymer fiber, with low but significant crystallinity, composed of at least 95 weight percent ethylene and at least one other olefin unit. This fiber is elastic and heat resistant substantially.

[026] "Polyester bi-component filament" means a continuous filament comprising a pair of polyesters closely adhered to each other along the length of the fiber, so that the fiber cross-section is, for example, a side-by-side. side, center of the eccentric hem or other suitable cross section from which useful rib can be developed. Fabric made from this filament, such as Elasterell-p, poly(trimethylene terephthalate)/poly(ethylene terephthalate) (PTT/PET) bicomponent fiber, has excellent recovery characteristics.

[027] "Non-elastomeric elastic fibers" means an elastic filament not containing elastomeric fibers. However, the recoverable stretch, these yarns must be greater than 20%, as tested by ASTM D6720 methods, such as textured poly(propylene terephthalate) (PPT) stretch filament, textured PET stretch filament, stretch filament fiber from bi-component, or poly(butylene terephthalate) (PBT) stretch filament.

[028] A "pre-covered elastic yarn" is one surrounded by, twisted with, or mixed with stiff yarn before the central spun process. Pre-covered elastic yarn that includes elastomeric fibers and stiff yarns is also termed a "pre-covered yarn" in the text of this specification. The hard yarn coating serves to protect the elastomeric fibers from abrasion during textile processes. This abrasion can result in breaks in the elastomeric fiber with consequent process interruptions and unwanted fabric non-uniformities. In addition, the covering helps to stabilize the elastic behavior of elastomeric fibers, so that the elongation of the pre-covered elastic yarn can be more uniformly controlled during textile processes than would be possible with elastomeric fibers without coverings. Pre-coated yarn can also increase the elastic modulus of yarn and fabric, which is useful for improving fabric recovery power and dimensional stabilities.

[029] Pre-covered yarns include: (a) single wrapping of elastomer fibers with a stiff yarn; (b) double wrapping the elastomer fibers with a stiff thread; (c) continuously covering (ie, core spun or core spun) an elastomer fiber with staple fibers, followed by twisting during winding; (d) braiding and entangling the elastomer and stiff strands with a jet of air; and (e) twisting an elastomer of stiff fibers and yarns together.

[030] "Double elastic composite yarn" is a composite yarn comprising two sets of central elastic fibers with single yarns, covered with hard staple fiber sheath. The term "double elastic wire" is used interchangeably throughout the specification.

[031] The elastic fabric of some embodiments includes double elastic central spun yarns in the weft direction. In some embodiments, a fabric with unexpectedly high recovery properties has been achieved, especially for superior elastic fabrics. This was accomplished by using central spun yarn containing two different elastic fibers with different stretching properties. Those skilled in the art will recognize that where weft stretch is desired, the fabric may include such center spun yarns with the elastic fibers doubled in the weft direction.

[032] As shown in Fig. 1, the double elastic yarn 8 according to the present invention will necessarily include two central filaments of elastic: central elastic I (4, in Fig. 1) and central elastic II (6, in Fig. 1). The central filaments of the elastic are preferably surrounded along their entire length by a fibrous sheath 2 comprising the spun staple fibers.

[033] An embodiment of a representative central rotating apparatus 40 is shown in Fig. 2. Two separate fiber making devices 46 and 64 are installed on the machine. During the center rotation process, central elastic filament I 48 and central elastic filament II 60 are placed by delivering the roll 46 and 64 separately and are combined with a stiff yarn to form a central spun yarn of the composite. The central elastic filaments of tube 48 and tuber 60 are unwound in the direction of arrow 50 and 62 by the positively directed action of feed rollers 46 and 64. Feed rollers 46 and 64 serve as a base for tube 48 and tube 60 and deliver the fiber elastic from the yarn 52 and 66 at a predetermined speed.

[034] The hard fiber or yarns 44 are unwound from the tube 54 to meet the central elastic filament 52 and 66 for the front roller assembly 42. The combined central elastic filaments 52, 66 and hard fiber 44 are central spun together in the spooling device. turn 56.

[035] The central elastic filament I 52 and central elastic filament II 66 are stretched (summoned) before entering the front rollers 42. The elastic filaments are stretched through the difference in speed between feed rollers 46 or 64 and front rollers 42. The delivery speed of the front rollers 42 is greater than the speed of the feed rollers 46 and 64. Adjusting the speed of the feed rollers 46 and 64 gives the desired cooking or draw ratio.

[036] The stretch ratio is typically 1.01X times to 5.0X times (1.01X to 5.0X) compared to unstretched fiber. Too low a draw ratio will result in poor quality yarns having through the grin and an off-center elastic filament. Too high a stretch ratio will result in elastic filament breakage and central void.

[037] Another embodiment of a representative central turning apparatus 40 is shown in Fig. 3. Core elastic I are uncoated elastic filaments 48, while core elastic II 12 is pre-covered elastic yarn. The central elastic II of the tube 12 is arranged in the direction of the arrow 62 by the action of positively directed feed rollers 64. The weighted roller 66 serves to maintain stable contact between the central elastic II and the feed rollers 64 in order to deliver the central elastic II of yarns 68 at a predetermined speed. Other elements in Fig. 3 are described by Fig. two.

[038] Another embodiment of a representative central turning apparatus 40 is shown in Fig. 4. Core elastic I are uncoated elastic filaments 48, while core elastic II 12 is pre-covered elastic yarn. The central elastic II of the tube 12 is withdrawn from the end and then passes through the guide bar and tension control device. The tension device serves to keep the wire tension stable at a predetermined level. The stretch ratio for uncoated elastic fiber is typically 1.01X times to 5.0X times (1.01X to 5.0X) compared to unstretched fiber. Other elements in Fig. 4 are described by Fig. two.

[039] According to some embodiments of the method, two elastic fibers with different properties and one hard fiber are covered together to form a composite yarn, in which the two elastic fibers are stretched to different confections from their original length during the process of wire cover. Two elastic fiber sewing can be selected from sewing 1.01X times to 5.0X times. For the two core elastic fibers with different deniers or different filament numbers, the stretch ratio of core elastic I and core elastic II could be different from each other depending on the elastic fiber performances and fabric quality requirement. In many cases, one core is designed more to provide high stretch performance, while another core is less stretched to provide fabrics with high recovery power and low shrinkage.

[040] In conventional fabrics, if the heat setting is not used to "set" the spandex, the fabric may have high shrinkage, excessive fabric weight, and excessive elongation, which can result in a negative consumer experience. Excessive shrinkage during the fabric coating process can result in crease marks on the fabric surface during processing and home washing. Creases that develop in this way are often very difficult to iron out.

[041] By using low sewing on one of the core elastic fibers, the high temperature heat setting step in the process can be avoided. This new process can reduce heat damage to certain fibers (ie cotton) and thus can improve the grip of the finished fabric. The fabrics of some embodiments may be prepared in the absence of a heat setting step including where the garment fabrics will be prepared. As an added benefit, heat sensitive hard yarns can be used in the de novo process to make shirts, elastic, fabrics, thus increasing the possibilities for different and improved products. In addition, the shorter process has productivity benefits for the fabric manufacturer.

[042] It was unexpectedly found that core yarns with two different core elastic fibers have greater stretch and recovery power than core spun yarns of single core elastic filament with the same denier. For example, center drawn yarns with two cores of 30D spandex/3filament plus 40D spandex/4filament, have more recovery power than a core yarn made in single core of 70D yarn/5filament within the same fabrication. So, we can make the center spun yarns with greater elongation and greater recovery power using the same spandex content.

[043] The two elastic fibers with different properties could be used and covered together with a hard fiber sheath to form a composite yarn, in which the two elastic fibers could have different polymer compositions and with different strain-strain behavior. An example is to use two spandex fibers with different heat set efficiency together within a central spun yarn, such as normal fiber T162C LYCRA® spandex fiber and T562B easy fix LYCRA® fiber. The fabric can be heat set at higher temperature than LYCRA® fiber easy set heat set temperature, but lower than normal heat set temperature of LYCRA® fiber. Thus, the fabrics only achieve partial thermal fixation which provides acceptable tissue shrinkage while good elongation and growth.

[044] Another example is the central strand containing central elastic I with high tension modulus and central elastic II with low tension modulus. The central elastic I provides the fabric with high power recovery and low tissue growth, while the central elastic II with low modulus gives the fabric easy stretch, low shrinkage, resulting in fabric with easy stretch while maintaining superior strength and stability of high dimension. Elastic fibers with different chemical compositions can also be combined together with a central spun yarn, such as Lastol and spandex polyolefin elastic fiber. Spandex fibers offer high recovery power while Lastol fibers contribute heat resistance and inferior shrinkage performance.

[045] The combination of central elastic I and central elastic II could be elastic fiber without coverage plus elastic fiber without coverage; or bare elastic fiber plus pre-covered elastic yarn, or pre-covered elastic yarn plus pre-covered elastic yarn. Uncovered elastic fiber can be from about 11 dtex to about 444 dtex (denier - about 10D to about 400D), including 11 dtex to about 180 dtex (denier 10D to about 162D).

[046] Pre-covered elastic yarn includes several types, such as single wrapping of elastomer fibers with a stiff yarn; double wrapping of the elastomer fibers with a stiff thread; continuously covering (i.e. center spinning) an elastomer fiber with staple fibers, followed by twisting during winding; braiding and entangling the elastomer and stiff yarns with a jet of air; and twisting an elastomer of stiff fibers and yarns together. The preferred pre-covered elastic yarn is air blast covered yarns of spandex with textured polyester and nylon filaments, such as 40D or 70D spandex with 50D to 150D polyester air covered yarn. The pre-covered elastic yarn is made on a separate machine before the center spun yarn process.

[047] The pre-covered elastic yarn can be present in any desired amount, for example from about 5 to about 35% percent based on the weight of the total double elastic yarn. The linear density of the pre-coated yarn ranges from about 15 denier (16.5 dtex) to about 900 denier (990 dtex), including from about 30 denier to 300 denier (33dtex to 330 dtex). When the yarn denier ratio between the pre-covered yarn and the total double elastic yarn is less than 35%, the fabric has no substantial through-grind. After the finishing process, two central elastic fibers, including a pre-covered yarn, are invisible and untouchable.

[048] The deniers of the uncoated elastic fiber (before coating to form the pre-coated yarn) can be from about 11 dtex to about 444 dtex (denier - about 10D to about 400D), including 11 dtex to about 180 dtex (denier 10D to about 162D). During the pre-coating process, the fiber's elastic is drawn between 1.1X to 6X its original length. In pre-covering, the elastic fiber is pre-covered with one or more hard yarns, with hard yarn denier from 10 to 600 deniers.

[049] Another combination of core elastic fiber I and core elastic fiber II could be a set of uncovered elastic fiber in addition to another set of non-elastomeric elastic fibers. The non-elastomeric elastic fibers may be PET stretch textured filaments, PPT stretch textured filaments, bi-component fiber, or PBT stretch fiber. It was surprising to find that when non-elastomeric elastic fiber with recoverable stretch greater than 20% was used as one of the core elastic fibers, the performance of the core spun yarns and the fabric changed dramatically. Fabrics have high stretch and high power recovery. The linear density of non-elastomeric elastic fibers can range from about 15 denier (16.5 dtex) to about 450 denier (495 dtex), the denier including about 30-150 denier (33dtex to 165 dtex). When the denier is too high, the fabric could be substantial across the grin.

[050] The elastic fiber content with double elastic core spun yarns are between about 0.1% to about 20%, including from about 0.5% to about 15%, and about 5% to about 10% based on yarn weight. Elastomeric fiber content within the fabric can be from about 0.01% to about 10% by weight, based on the total weight of the fabric, including from about 0.5% to about 5%.

[051] The sheath staples in the double elastic yarn may be fibers of a nature such as cotton, wool or linen. They can also be man made staple or synthetic fibers of monocomponent poly(ethylene terephthalate) and poly(trimethylene terephthalate) fiber, polycaprolactam fiber, poly(hexamethylene adipamido) fibers, acrylic fibers, modacrylic, fiber acetate, Rayon fibers, Nylon and their combinations.

[052] Such double elastic yarns can be used to make a stretch fabric where various knit patterns can be applied, including plain, poplin, twill, oxford, dobby, satin, satin and combinations thereof. Fabrics of some embodiments may have an elongation of about 10% to about 45% in the warp and/or weft direction. Fabrics may have shrinkage of about 15% or less after washing. Flat fabric stretch can have an excellent cotton feel. Garments can be prepared from the fabrics described herein.

[053] The warp yarn may be the same as, or different from, the weft yarns. The fabric may be weft stretch only, or it may be bi-stretch, where useful stretch and recovery properties are exhibited in both the warp and weft directions.

[054] Air jet loom, rapier loom, projectile loom, water jet loom and transport loom can be used. Dyeing and finishing process are important in producing a satisfactory fabric. The fabric can be finished in the continuous scale processes and part of the jet dye processes. Conventional equipment found in a continuous finishing plant and part of dyeing plants are generally suitable for processing. Normal finishing process sequences include preparation, dyeing and finishing. In the preparation and dyeing process, including cornering, peeling, washing, bleaching, mercerizing and dyeing, normal processing methods for stretch fabrics are generally satisfactory.

ANALYTICAL METHODS: RECOVERABLE WIRE STRETCH

[055] The recoverable stretch of elastic fibers used in the examples was measured as follows. Each yarn sample was formed from a skein of 5000 +/-5 total denier (5550 dtex) with a spool of spool at a tension of about 0.1 gpd (0.09 dN/tex). The ball was conditioned at 70°F (+/-2°F) (210 +/-1°C.) and 65% relative humidity (+/-2%) for a minimum of 16 hours. The skein hanging vertically substantially from a support, a weight of 6 mg/den (5.4 mg/dtex) (e.g. 30 grams for a skein of 5550 dtex) was hung at the bottom of the skein, the weighted skein was allowed to come to an equilibrium length, and the skein length was measured to within 1 mm and recorded as "Cb" - The 5.4 mg/dtex weight was left on the skein for the duration of the test. Then, a weight of 1030 grams (206 mg/d; 185.4 mg/dtex) was hung from the bottom of the ball, and the length of the ball was measured to within 1 mm and recorded as "Lb".

[056] The 1030 g weight was removed, and the ball was then immersed in boiling water for 10 minutes at 100 °C degree water, after which the balls were removed from the water and conditioned as above for 16 hours. . This step is designed to simulate the relaxation process of commercial fabric, which is a way of developing fabric stretch. The skein length was measured as above, and its length was recorded as "Ca". The 1030-gram weight was again hung from the skein, and the skein length was measured as above and engraved as "La". The relaxation after recoverable stretching of the yarn (percent), "CCa", was calculated according to the formula CCa= 100x(La-Ca)/La. Yarn shrinkage was calculated according to the formula Cs (%) = 100 X (Lb-La)/Lb.

FLAT TISSUE STRETCHING (STRETCHING)

[057] Fabrics are rated for % elongation under specified load (ie force) in the fabric stretch direction(s), which is the direction of the composite yarns (ie weft, warp, or weft and warp). Three samples measuring 60 cm x 6.5 cm were cut from the fabric. The time dimension (60 cm) corresponds to the stretch direction. Samples are partially unraveled to reduce sample widths to 5.0 cm. The samples are then conditioned for at least 16 hours at 20°C +/-2°C and 65% relative humidity, +/-2%.

[058] The first reference was made across the entire width of each sample, 6.5 cm from one end of the sample. A second reference was made across the entire width of the sample at 50.0 cm from the first reference. Excess tissue from the second reference to the other end of the sample was used to form and sew a loop into which a metal pin could be inserted. A notch was then cut into a loop so that weights could be attached to the metal pin.

[059] The loop-free end of the sample was fixed and the tissue sample was hung vertically. A 17.8 Newton (N) (4 LB) weight is attached to the metal pin through the fabric hanging in a loop so that the tissue sample is stretched by the weight. The sample was "exercised", allowing it to be stretched by the weight for three seconds and then manually relieved by lifting the weight. This cycle was performed three times. The weight was then allowed to hang, thus extending the tissue sample. The distance in millimeters between the two references was measured while the fabric was under load, and this distance is designated ML. The original distance between the references (ie, unstretched distance) was designated GL. The tissue elongation % for each individual sample, calculated as follows:

[060] The results of three stretches were averaged for the final result.

FLAT TISSUE GROWTH (UNRECOVERED STRETCH)

[061] After stretching, a tissue with no growth would recover exactly to its original length before stretching. Typically, however, stretch fabrics will not fully recover and will be slightly longer after prolonged stretching. This slight increase in length is called "growth".

[062] The above tissue stretch test must be completed prior to the growth test. Only the fabric stretch direction was tested. For elastic fabric in both directions, both directions were tested. Three samples, each 55.0 cm x 6.0 cm, were cut from the fabric. These were different samples than those used in the elongation test. The 55.0 cm direction must match the stretch direction. Samples were partially unraveled to reduce sample widths to 5.0 cm. The samples were conditioned in temperature and humidity, as in the elongation test above. Two references exactly 50 cm apart were drawn across the width of the samples.

[063] The known elongation % (E%) from the elongation test was used to calculate the length of the samples at 80% of this known elongation. This was calculated as

onde L2 foi o aumento no comprimento entre as referências da amostra após relaxamento e L era o comprimento original entre os pontos de referência. Este crescimento % foi medido para cada amostra e os resultados em média para determinar o número de crescimento.[064] where L was the original length between the reference points (ie 50.0 cm). Both ends of a sample were clamped and the sample was stretched to the length between the equaled references L+E (length), calculated above. This stretch was maintained for 30 minutes, after which the stretch force time was released and the specimen was allowed to walk freely and relax. After 60 minutes the % growth was measured as

where L2 was the increase in length between the sample references after relaxation and L was the original length between the reference points. This % growth was measured for each sample and the results averaged to determine the growth number.

SHRINKAGE OF FLAT FABRICS

[065] Fabric shrinkage was measured after washing. The fabric was first conditioned to temperature and humidity as the elongation and growth tests. Two samples (60 cm x 60 cm) were then cut from the tissue. Samples were taken at least 15 cm from the tissue. A four-sided box measuring 40cm x 40cm was marked on the tissue samples.

[066] The samples were washed in a washing machine with the samples and a loading fabric. The total washing machine load was 2 kg of air-dried material, and no more than half of the wash consisted of samples for analysis. The laundry was gently washed at a water temperature of 40 °C and wrung out. An amount of detergent from 1 g/l to 3 g/l was used, depending on the strength of the water. The samples were placed on a flat surface until dry, and then they were conditioned for 16 hours at 20 °C +/-2 °C and 65% relative humidity +/2% rh.

onde L1 foi a distância original entre as marcações (40 cm) e L2 é a distância após a secagem. Os resultados são em média para as amostras e relatados para direções da trama e do urdume. Números negativos de encolhimento refletem a expansão, o que era possível em alguns casos por causa do comportamento de fio duro.[067] Fabric sample shrinkage was then measured in the warp and weft directions by measuring the distances between markings. Shrinkage after washing, C %, was calculated as

where L1 was the original distance between the markings (40 cm) and L2 is the distance after drying. Results are averaged for samples and reported for weft and warp directions. Negative shrinkage numbers reflect expansion, which was possible in some cases because of the stiff wire behavior.

TISSUE WEIGHT

[068] Flat tissue samples were perforated by a die with a diameter of 10 cm. Each cut flat tissue sample was weighed in grams. "Fabric weight" was then calculated as grams/square meters.

EXAMPLES

[069] The following examples demonstrate the present invention and its ability for use in the manufacture of a variety of fabrics. The invention is capable of other and different embodiments, and its various details are capable of modifications in various apparent aspects, without departing from the scope and sense of the present invention. In that sense, the examples are considered illustrative in nature and not so restrictive.

[070] For each of the following denim fabric examples, 100% cotton open end center spun yarn or ring woven was used as the warp yarn. For denim fabrics, they included two count yarns: 7.0 Ne OE yarns and 8.5 Ne OE yarns, with irregular arrangement pattern. The threads were dyed indigo in the form of a rope before radiant. Then, the weaving beam was made of size and made. For lower weight fabrics, the warp yarn is 20Ne 100% cotton ring twisted yarn. They were of size and made the weaving beam.

[071] Table 1 lists four examples of core spun yarns with a traditional core elastic filament and innovative yarn containing two core elastic sets.

[072] The various central spun yarns with double elastic fibers were used as the weft yarn. Several core elastic fibers, including bare spandex, polyester/pre-coated LYCRA® spandex fiber, or pre-coated nylon/spandex yarn, were used as the core. Table 2 lists the materials and process forms that were used to make the center spun yarns for each example. Table 3 shows the detail fabric structure and performance summary for each fabric. Lycra® spandex are available from Invista, s. The. a. L, Wichita, KS. For example, in the column titled spandex 40D means 40 denier; 3.5X means Lycra® sewing imposed by the central spinning machine (machine sewing). In the column entitled 'rigid sheath yarn', 20' s is the linear density of the twisted yarn as measured by the English Cotton Counting System. The rest of the items in Table 1 and Table 2 are clearly labeled.

[073] Stretch flat fabrics were subsequently made using the center spun yarns from each example in Table 2. Table 3 summarizes the yarns used in the fabrics, the weaving pattern and the quality characteristics of the fabrics. Some additional comments for each of the examples are given below. Unless otherwise noted, fabrics were woven on an air jet loom or Donier rapier. Loom speed was 500 picks/minute. The fabric widths were about 76 and about 72 inches loom and greige state respectively. The loom has double-beam capacity weaving.

[074] Each greige fabric in the examples was finished by a jiggle dyeing machine. Each flat fabric was prewashed with 3.0 wt% Lubit®64 (Sybron Inc.) at 49°C for 10 minutes.

TABELA 2: DESCRIÇÃO DE FIOS DE TRAMA

TABELA 3: LISTA DO EXEMPLO DO TECIDO

[075] After it was sized with 6.0 wt% Synthazyme® (Dooley Chemicals. LLC Inc.) and 2.0 wt% Merpol® LFH (EI DuPont co.) for 30 minutes at 71°C and then washed with 3.0 wt% Lubit® 64, 0.5 wt% Merpol® LFH and 0.5 wt% trisodium phosphate at 82°C for 30 minutes. Fabric finishing was followed by drying on a frame at 160 °C for 1 minute. TABLE 1. EXAMPLES OF YARN WITH DOUBLE CENTRAL ELASTIC FIBERS

TABLE 2: DESCRIPTION OF WEFT THREADS

TABLE 3: TISSUE EXAMPLE LIST

YARN EXAMPLE A: TYPICAL CENTER SPUN YARN WITH A CENTER ELASTIC FIBER.

[076] This is not an innovative yarn. This center spun yarn is 16Ne with a 40d LYCRA® spandex fiber covered in the cotton sheath. The fabrication of LYCRA® fiber is 3.5X during the covering process. Cotton TM's twist level is 18 twisters per inch. This yarn has 17.71% stretch recoverable after boiling.

YARN B EXAMPLE: CENTER SPUN YARN WITH TWO CENTRAL ELASTIC FIBERS

[077] The center spun yarn is 16Ne with two sets of LYCRA® spandex fiber covered by the cotton sheath. Core elastic fiber I is 20D T162B and core elastic fiber II is 20D T162B as well. The total denier of the thinnest elastic is 40 denier. The fabrication of LYCRA® fiber is 3.5X during the covering process. Cotton TM's twist level is 18 twisters per inch. Therefore, this center spun yarn has the same structure as an Example Yarn A, including in the yarn count, twist level denier LYCRA® fiber, except with 2 sets of center elastic filaments instead of one end of the spun yarn. central. The recoverable stretch of this yarn is 20.63%, which has 2.92% higher unit than the yarn in sample A. This means that the yarn with two central sets of filaments has higher recoverable stretch than the yarn with a single central set of filament under the same spandex content. In this way, the innovative yarn can provide high stretch and high power recovery to fabrics, using the same amount of elastic fibers.

YARN C EXAMPLE: TYPICAL CENTER SPUN YARN WITH A CENTER ELASTIC FIBER.

[078] This is not an innovative yarn. The center spun yarn is 16Ne with a 70d LYCRA® spandex fiber covered in the cotton sheath. The fabrication of LYCRA® fiber is 3.8X during the covering process. Cotton TM's twist level is 18 twisters per inch. This yarn has 38.71% recoverable stretch after boiling and the yarn has 2.28 shrinkage.

YARN D EXAMPLE: CENTER SPUN YARN WITH TWO CENTRAL ELASTIC FIBERS

[079] The center spun yarn is 16Ne with two sets of LYCRA® spandex fibers covered by the cotton sheath. The central elastic fiber is 30D T162B and the central elastic fiber II is 40D T162B. The total denier of the thinnest elastic is 70 denier. The fabrication of both LYCRA® fibers is 3.8X during the coating process. Cotton TM's twist level is 18 twisters per inch. Therefore, this core spun yarn has the same structure as Example Yarn C, except with 2 sets of core elastic filaments instead of 1 set of core spun yarns. The recoverable stretch of this yarn is 40.88%, which is 2.17% higher unit than the sample of yarn C. This shows that the yarn with two sets of central filaments has high recoverable stretch than the yarn with a single set of central filament under the same spandex content. In this way, the innovative yarn can provide high stretch and high power recovery to fabrics, using the same amount of elastic fibers.

EXAMPLE 1: TYPICAL STRETCH OF LOWER WEIGHT FABRICS

[080] This is an example of comparison, not according to the invention. The warp yarn was 40/2Ne ring twisted yarn count. The weft yarn was 20 Ne cotton with 40D Lycra® core spun yarns. Lycra® fabrication is 3.5X. This weft yarn was a typical draw yarn used in drawing typical khaki fabrics. Loom speed was 500 picks per minute at a pick level of 56 picks per inch. Table 3 summarizes the test results. The results show that, after finishing, this fabric had weight (8.95 g/m2), stretch (37.6%), width (50.5 inches), wash weft shrinkage (0.91%) and tissue growth (8.7%). The data indicate that this combination of stretch yarns and fabric construction caused superior fabric growth.

EXAMPLE 2: TISSUE STRETCH WITH DOUBLE ELASTIC FIBERS

[081] This sample had the same fabric structure as in example 1. The only difference was the use of 20s of weft yarn containing double core elastic fibers: 40D LYCRA® fiber with 3.5X fabrication and LYCRA fiber ®40d with 1.8X cooking. The warp yarn was 40/2 Ne of ring woven cotton. Loom speed was 500 picks per minute at 56 picks per inch. Table 3 summarizes the test results. It is clearly shown that this sample has similar stretch but lower tissue growth level (6.4%).

[082] Therefore, by using two different confections of the core elastic fibers within the same yarn, the covered yarn and the fabric can achieve different characteristics. For example, high sewing on central elastic fiber I gives fabric with high stretch, while sewing low on central elastic fiber II gives tissue with low growth, high recovery, but does not increase tissue shrinkage. In this way, fabrics with high stretch, low shrinkage and high recovery can be produced.

EXAMPLE 3: STRETCHING THE TISSUE CONTAINING DOUBLE ELASTIC FIBERS

[083] This sample had the same fabric structure as in example 1. The only difference was the use of the central spun yarns in the weft: T162B LYCRA® 40D fiber with 3.5X and 40d fabrication, easy fixing of the LYCRA® fiber with 3.5X confection. The warp yarn was 20 Ne 100% cotton ring twisted yarn. 3/1 twill weave pattern has been applied. The finished fabric had weight (9.19 g/m2), 38.4.0% stretch and 7.9% growth in the weft direction. It showcases the clear, easy-fix LYCRA® fiber in the Central Elastic II keeping fabrics at the stretch level while reducing fabric growth from 8.7% in Example 1 to 7.9%.

[084] LYCRA® Easy Set Fiber can be heat set at about 170°C degrees, which is approximately 20°C lower than the heat set temperature of T162B LYCRA® fiber. Therefore, when the fabrics are heat-fixed at a temperature between 170°C and 190°C, the fabric is partially thermoset. Only LYCRA ® and T162B thermosetting fiber is not defined. In this way, the fabric maintains improved stretch and recovery while the shrinkage keeps it under a certain level.

EXAMPLE 4: STRETCH FABRIC WITH SPANDEX AND ELASTIC POLYOLEFIN FIBER

[085] The warp yarn was 7.0 Ne count and 8.4 Ne count mixed in the yarn end opening. The warp yarn was dyed indigo before radiant. The weft yarn is 16Ne of the center spun yarns with 40D T162B Lycra® spandex and 40D elastic polyolefin fiber. Lycra ® fiber and polyester stretch fiber were worked up 3.5X during the covering process. Table 3 lists the fabric properties. Fabric made from such yarns exhibited good cotton hand, good stretch (47.8%) and good recovery (6.5% growth). All test results indicate that the combination of spandex filaments and elastic polyolefin can produce tissue growth and good stretch. The fabric has no grin. Elastic filaments, cannot be seen from the fabric surface and back fabric.

[086] Compared with spandex, elastic polyolefin fiber or Lastol fiber has lower recovery power, but better heat resistance, better chemical resistance, low-shrink fabric and good cotton hand touch feeling. Fabrics contained with lycra and elastic polyolefin can provide good stretch and good recovery with better heat resistance, low shrinkage and better chemical resistance, such as chlorine resistance in swimming pool and denim bleaching processes.

EXAMPLE 5: STRETCH FABRIC CONTAINING SPANDEX AND PRE-COVERED ELASTIC YARN

[087] This sample had the same fabric structure as in example 1. The difference was the central spun yarns in the weft direction, which contained an uncoated 40D LYCRA® fiber and a pre-covered elastic yarn (40D/34f yarn Nylon/40D Lycra® air-covered yarn) on the center yarn. The uncoated fabric of LYCRA® 40D fiber is 1.8X and the fabrication of LYCRA® fiber in the pre-covered elastic yarn is 3.2X. This fabric used the same warp and structure as Example 1. In addition, the weaving and finishing process were the same as Example 1. Table 3 summarizes the test results. We can see that this sample had good elongation (35.9%), good weave direction wash shrinkage (0.65%) and fabric growth (5.3%). The appearance of the fabric and handle was excellent. After adding the pre-covered elastic yarn (Nylon fiber/40D Lycra® 40D/34f AJY yarn), tissue growth noticeably reduced.

EXAMPLE 6: STRETCH FABRIC CONTAINING SPANDEX AND PRE-COVERED ELASTIC YARN

[088] This sample had the same fabric structure as in example 5. The only difference was that the LYCRA® 40D fiber was made without covering during the covering process. The uncoated LYCRA® fiber confection is 3.5X while it was 1.8X in example 5. The fabric weight was 8.96 OZ/yd2, and the weft elongation was 37.8%. The fabric had very low growth (5.9%) in the weft. This example further confirms that the addition of additional elastic composite yarn can produce high performance elastic fabrics with low growth. Double elastic yarn makes the fabric growth to 5.9% from 8.7% in Example 1. Compared to Example 5, the sewing also results in increased weight and stretch.

EXAMPLE 7: STRETCH DENIM CONTAINING SPANDEX AND PRE-COVERED ELASTIC YARN

[089] This example had the same warp yarn and the same fabric structure as Example 4. The warp yarn was 7.0 Ne count and 8.4 Ne count mixed at the yarn end opening. The warp yarn was dyed indigo before radiant. The weft yarn is 16Ne central spun yarn with 40D Lycra® spandex and 50D/24f polyester 40D LYCRA® fiber from air jet covered yarn. Lycra® sewing is 3.5X and 1.8X in composite core and uncoated. This example is a fabric of innovation. Loom speed was 500 picks per minute at a pick level of 44 picks per inch. Table 3 summarizes the test results. The results show that, after washing, this fabric had a weight (12.80 OZ/Y2), a weft stretch of 35.3% and a weft growth of 3.5%.

EXAMPLE 8: STRETCH DENIM CONTAINING SPANDEX AND PRE-COVERED ELASTIC YARN

[090] This example had the same warp yarn and the same fabric structure as Example 7, except the LYCRA® fiber fabric pre-coated the elastic yarn (2.6X fabrication in Example 8 vs. 1.8X fabrication in Example 7)). Table 3 summarizes the test results. It is clear that this sample had good elongation (40.4% weft) compared to sample 7.

EXAMPLE 9: STRETCH FABRIC WITH SPANDEX AND PBT STRETCH FIBER

[091] This example had the same warp and fabric structure as Examples 7 and 8, except using 50D/26f PBT stretch fiber as core elastic II fiber. This uncoated PBT 50D/26f fiber has 40.23% recoverable stretch and 3.44% shrinkage tested with ASTM method D6720. The central elastic I of the Lycra® fiber was made 3.5X during the covering process. Table 3 lists the fabric properties.

[092] Fabric made from such yarns exhibited good cotton hand, good stretch (40.7%), and good recovery (6.0% growth). All test results indicate that the combination of spandex and non-elastomeric stretch filaments can produce good tissue growth and stretch. Fabric has no grin through: elastic filaments, can't be seen from fabric surface and fabric back.

Claims (20)

1. ARTICLE, characterized in that it comprises central spun yarns (8) comprising: (a) a sheath of hard fibers (2); (b) core elastic fiber I (4), wherein core elastic fiber I (4) is an elastic fiber assembly comprising spandex; and (c) core elastic fiber II (6), wherein core elastic fiber II (6) is an elastic fiber assembly comprising spandex; wherein the central elastic fiber I (4) and the central elastic fiber II (6) have different elastic properties. ARTICLE according to claim 1, characterized in that the central elastic fiber I (4) and the central elastic fiber II (6) have different deniers or different filaments. ARTICLE according to claim 1, characterized in that the central elastic fiber I (4) and the central elastic fiber II (6) have different fabrications. ARTICLE according to claim 1, characterized in that the central elastic fiber I (4) and the central elastic fiber II (6) have different polymer compositions. ARTICLE according to claim 1, characterized in that the at least one central elastic fiber comprises elastomeric fibers having denier from 10 denier to 450 denier. ARTICLE according to claim 1, characterized in that the at least one central elastic fiber comprises elastic polyolefin fibers having denier from 10 denier to 450 denier. ARTICLE according to claim 6, characterized in that the elastic polyolefin fiber is a lastol fiber. ARTICLE according to claim 1, characterized in that at least one set of core elastic yarns are pre-covered elastic yarns having denier from 15 denier to 300 denier. ARTICLE according to claim 8, characterized in that the pre-covered elastic yarns include a cover selected from the group of air-covered yarn, single-coated yarn, double-coated yarn, and combinations thereof. ARTICLE according to claim 8, characterized in that the pre-covered elastic yarn is a polyester and spandex air-covered yarn. ARTICLE according to claim 1, characterized in that the at least one central elastic fiber includes non-elastomeric elastic fibers having a denier of 15 denier to 450 denier. ARTICLE according to claim 11, characterized in that the non-elastomeric elastic yarn is selected from the group of filaments with yarn recoverable elasticity greater than 20% tested with ASTM method D6720-07. ARTICLE according to claim 12, characterized in that said non-elastomeric elastic yarn comprises at least one fiber selected from the group consisting of polyester, nylon, poly(trimethylene terephthalate) (PTT) fiber, poly fiber (butylene terephthalate) (PBT), bi-component fiber and combinations thereof. ARTICLE according to claim 1, characterized in that the hard fiber sheath (2) is selected from the group consisting of wool, linen, silk, polyester, nylon, olefin, cotton and combinations thereof. ARTICLE according to claim 1, characterized in that it comprises a plain fabric with warp yarns and weft yarns, wherein at least one of the warp yarns and weft yarns includes the center spun yarns (8). 16. ARTICLE, according to claim 15, characterized in that the fabric has elasticity in the weft direction, between 10 and 45%. ARTICLE according to claim 15, wherein said fabric comprises a garment. 18. A METHOD FOR MANUFACTURING AN ARTICLE, as defined in any one of claims 1 to 17, characterized in that it comprises a plain weave with warp yarns and weft yarns, wherein the warp yarn or weft yarn or both of the warp yarns warp and weft have the center spun yarns (8) as defined in claim 1. 19. ELASTIC FABRIC, characterized in that it comprises a central spun yarn (8), as defined in claim 1. FABRIC according to claim 19, characterized in that the fabric is a plain, warp or knitted fabric.

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