TWI649470B - Stretch yarns and fabrics with multiple elastic yarns - Google Patents

Abstract

This article includes articles and methods including core spun yarns. The core spun yarn comprises a hard fiber sheath and two sets of elastic fibers, wherein the sets of elastic fibers have different properties. These properties may differ in one or more aspects, such as having different Dani numbers, compositions, or drafting. The one or two sets of elastic fibers may be pre-covered.

Description

Telescopic yarn and fabric with a plurality of elastic yarns

The present invention relates to the manufacture of stretch composite yarns and fabrics. In particular, the present invention relates to fabrics and methods comprising two sets of elastic core fibers in a single yarn.

Stretch fabrics with elastic composite yarns have been on the market for a long time. Fabric and apparel manufacturers generally know how to make fabrics with accurate quality parameters to achieve a fabric acceptable to the consumer. In current commercial fabrics, only one elastic fiber system is present in the yarn and fabric. An elastic fiber provides a dual role: flexibility and recovery. This makes it difficult to obtain a fabric which is easy to stretch, has high recovery, and has low shrinkage.

Easy to stretch is an important feature of clothing comfort. In the case of a garment that is more comfortable, the fabric can be easily stretched when the garment is worn on a person and moved. The garment exerts low pressure on the body. The garment can be cut to achieve a more streamlined look and better fit to the body while also ensuring the wearer's comfort during exercise. This property is achieved by low fabric tensile modulus by minimizing the resistance of the garment to body requirements during exercise.

However, in the case of fabrics having a low tensile modulus, a typical quality problem is that the fabric cannot be quickly restored to its original size and shape after the fabric is overstretched in certain parts of the body, such as the knees, buttocks and waist. Especially for fabrics with high stretch. Generally, the fabric has low restoring force when the tensile modulus is low. Consumers for a long time You will experience loose sagging after wearing.

Conversely, in order to obtain a fabric with good recovery, additional shrinkage forces are required within the fabric. Higher or more powerful elastic fibers can be added to the fabric. However, these fabrics have a high elongation modulus and a high binding force. Consumers complain that there is a high level of clothing stress and are uncomfortable during wear and exercise. At the same time, the fabric is less dimensionally stable. Heat setting is the necessary treatment to control fabric shrinkage. The shape retention and recovery of the fabric can impair the comfort and freedom of movement of the garment. There is still a need for fabrics that are easy to stretch, have high recovery, and have low shrinkage.

Composite elastic yarns have been well known for many years. For example, according to U.S. Patent Nos. 4,470,250, 4,998,403, 7,134,265, 6,848,151, elastomeric fibers (such as spandex) have been covered with relatively inelastic fibers to facilitate knitting or weaving. It is treated and provides an elastic composite yarn with acceptable properties for a variety of end fabrics. In U.S. Patent Application No. US 2008/0268734 A1 and USA 2008/0318485 A1, rigid filaments are used along with elastic filaments as the core within the core spun yarn.

Therefore, there is a need to produce a stretchable woven fabric which is easy to stretch, easy to handle, has low shrinkage, is suitable for garment making, and has excellent resilience and low growth.

One aspect includes a method for making a composite yarn having two different sets of elastic core fibers, referred to as a bielastic composite yarn. Also included are bi-elastic composite yarns and stretch fabrics and garments made from such yarns.

According to a first embodiment of the method, two sets of elastic fibers having different properties are covered with hard fibers to form a composite yarn, wherein the two sets of elastic fibers are stretched to different lengths of the original length during yarn covering. . The elastic fiber may be a bare spandex yarn of 11 to 560 dtex, and the hard fiber has a yarn count of 10 to 900 dtex. A suitable hard yarn is a cotton yarn. The elastic core fibers I and the elastic core fibers II are independently selected from elastomeric or non-elastomeric fibers.

According to a second embodiment of the method, two sets of elastic fibers (elastic core fibers I and elastic core fibers II) having different properties are covered with hard fibers to form a composite yarn, wherein the two sets of elastic fibers have different polymers Composition and have different stress-strain behaviors. The elastic fibers may be a bare spandex yarn of 11 to 560 dtex, and the hard fiber has a yarn count of 10 to 900 dtex. A suitable hard yarn is a cotton yarn.

According to a third embodiment of the method, two different sets of elastic core fibers (elastic core fibers I and elastic core fibers II) are covered with hard fibers to form a composite yarn, wherein at least one set of elastic core fibers is pre-coated elastic Yarn. Another group of core elastic yarns can be bare spandex yarn or pre-coated elastic yarn. The denier of the bare spandex yarn is 11 to 560 dtex, and the hard fiber has a yarn count of 10 to 900 dtex. A suitable hard yarn is a cotton yarn.

According to a fourth embodiment of the method, two different sets of elastic core fibers are coated with hard fibers to form a composite yarn, wherein at least one of the elastic core fibers is a non-elastomeric stretch fiber. Another set of elastic core yarns can be bare elastomers, such as spandex. The denier of the bare spandex yarn is 11 to 560 dtex, and the hard fiber has a yarn count of 10 to 900 dtex. A suitable hard yarn is a cotton yarn.

The fabric is made by using a double elastic yarn produced by one of the alternative methods. The double elastic yarn is used in at least one direction of the fabric. Any form of fabric can be used, including wovens, circular knits, warp knits, and narrow fabrics. Other treatments include scouring, bleaching, dyeing, drying, pre-shrinking, singeing, desizing, mercerizing, and any combination of these steps. The resulting stretch fabric can be processed into a garment.

2‧‧‧fiber sheath

4‧‧‧Elastic core I

6‧‧‧Elastic core II

8‧‧‧Double elastic yarn

12‧‧‧Tube/elastic core II

40‧‧‧core spinning device

42‧‧‧Pre-pressing roller set

44‧‧‧hard fiber/yarn

46‧‧‧Fiber drafting device/feeding roller

48‧‧‧Elastic core filament I/tube

50‧‧‧Unwinding direction

52‧‧‧elastic core filament I

54‧‧‧ yarn tube

56‧‧‧Spinning device

60‧‧‧Flexible core filament II/tube

62‧‧‧Unwinding direction

64‧‧‧Fiber drafting device/feeding roller

66‧‧‧elastic core filament II/heavy roller

68‧‧‧Yarn

The detailed description will refer to the following drawings in which like numerals refer to the same elements, and wherein: Figure 1 shows a core yarn having two elastic cores.

Figure 2 schematically depicts a core having two drafting devices for two bare elastic fibers Spinning device.

Figure 3 schematically depicts a core spinning device having two drafting devices with weighting rolls.

Figure 4 schematically depicts a core spinning device having two drafting devices for a bare elastic fiber and a pre-coated elastic yarn.

Elastomeric fibers are commonly used to provide stretch and elastic recovery in woven fabrics and garments. "Elastomer fiber" is a continuous filament containing no diluent (optionally a multifilament as appropriate) or a plurality of filaments having an elongation at break of more than 100% (independent of any crimp). The elastomeric fibers are stretched (1) to twice their length; (2) held for one minute; then (3) released, retracted to less than 1.5 times their original length within one minute of release. As used herein, "elastomeric fiber" means at least one elastomeric fiber or filament. Such elastomeric fibers include, but are not limited to, rubber filaments, bicomponent filaments and elastomeric esters, lastol and spandex.

"Spandex" is a synthetic filament in which the filament forming material is a long chain synthetic polymer composed of at least 85% by weight of block polyurethane.

The "elastic ester" is a synthetic filament in which the fiber-forming material is a long-chain synthetic polymer composed of at least 50% by weight of an aliphatic polyether and at least 35% by weight of a polyester.

"Two-component filament" is a continuous filament or fiber comprising at least two polymers bonded to each other along the length of the filament, each polymer belonging to a different general category, for example, an elastomeric polyether amide core having lobes Or a polythene sheath of the flap.

"Lastol" is a fiber that is combined into a polymer having a low but significant degree of crystallinity consisting of at least 95% by weight of ethylene and at least one other olefinic unit. The fiber is elastic and substantially heat resistant.

"Polyester two-component filament" means a continuous filament comprising a pair of closely adhering to each other along the length of the fiber such that the cross-section of the fiber is, for example, juxtaposed, eccentric sheath-core or other A polyester having a suitable cross section of curl is developed. Fabrics made from the filaments (such as Elasterell-p, PTT/PET bicomponent fibers) have excellent recovery characteristics.

"Non-elastomeric elastic fiber" means a stretchable filament which does not contain an elastomer fiber. However, the recoverable stretchability of this yarn must be higher than 20% (determined by ASTM D6720 method, such as ASTM D6720-07), such as structured PPT stretch filaments, structured PET stretch filaments, two-component stretch length Silk fiber or PBT stretch filament.

"Pre-covered elastic yarn" is an elastic yarn that is wrapped, wound or entangled by a hard yarn before the core process. Pre-coated elastic yarns comprising elastomeric fibers and hard yarns are also referred to herein as "pre-covered yarns". The hard yarn covering acts to protect the elastomeric fibers from abrasion during the textile process. This wear can result in breakage of the elastomeric fibers, subsequent process interruptions, and undesired fabric non-uniformities. In addition, the covering helps to stabilize the elastic behavior of the elastomeric fibers so that the elongation of the pre-coated elastic yarns can be controlled more uniformly during the textile process than with bare elastomer fibers. The pre-covering yarn also increases the tensile modulus of the yarn and fabric, which helps to improve the restoring force and dimensional stability of the fabric.

The pre-covering yarns comprise: (a) winding the elastomeric fibers with a hard yarn in a single winding manner; (b) winding the elastomeric fibers with a hard yarn in a double-wound manner; (c) continuously covering the elastomer with short fibers Fiber (ie, core spun yarn), which is subsequently twisted during winding; (d) entangled and entangled the elastomer and hard yarn with an air nozzle; and (e) elastomeric fibers and hard The yarns are twisted together.

The "double elastic composite yarn" is a composite yarn comprising two sets of elastic core fibers having a single yarn and covered with a rigid short fiber outer sheath. The term "double elastic yarn" is used interchangeably throughout the specification.

The stretch fabric of some embodiments includes a double elastic core yarn in the weft direction. In some embodiments, fabrics with unexpectedly high recovery properties are obtained, especially for highly stretchable fabrics. This is achieved by using a core yarn comprising two different elastic fibers having different stretching properties. Those skilled in the art will appreciate that when latitudinal expansion is required, the fabric can be wrapped. Such a core yarn having double elastic fibers in the weft direction.

As shown in Fig. 1, the double elastic yarn 8 of the present invention will necessarily comprise two types of elastic filament cores: an elastic core I (4 in Fig. 1) and an elastic core II (6 in Fig. 1). The elastic core filaments are preferably surrounded by a fiber sheath 2 along their entire length, the fibrous sheath 2 being composed of spun staple fibers.

FIG. 2 shows an embodiment of a typical core spinning device 40. Two separate fiber drafting devices 46 and 64 are mounted on the machine. During the core spinning process, the elastic core filaments I 48 and the elastic core filaments II 60 are placed on the transfer rolls 46 and 64, respectively, and combined with the hard yarn to form a composite core spun yarn. The core elastic filaments from the bobbin 48 and the bobbin 60 are unwound in the direction of the arrows 50 and 62 by the action of the forward drive feed rollers 46 and 64. The feed rollers 46 and 64 serve as brackets for the bobbin 48 and the bobbin 60, and convey the elastic fibers of the yarns 52 and 66 at a predetermined speed.

The hard fibers or yarns 44 are unwound from the bobbin 54 to bond with the elastic core filaments 52 and 66 at the front pressure roller set 42. The combined elastic core filaments 52, 66 and hard fibers 44 are core spun together on a spinning device 56.

The elastic core filament I 52 and the elastic core filament II 66 are stretched (drawn) before entering the front pressure roller 42. The elastic filaments are stretched by the difference in speed between the feed roller 46 or 64 and the front pressure roller 42. The conveying speed of the front pressure roller 42 is greater than the speed of the feed rollers 46 and 64. The speed of the feed rolls 46 and 64 is adjusted to achieve the desired draft or draw ratio.

The draw ratio is usually from 1.01X to 5.0X (1.01X to 5.0X) as compared with the undrawn fiber. If the draw ratio is too low, a low-quality yarn having a grin-through phenomenon and in which the elastic filaments are not concentrated will be obtained. Excessive draw ratio will result in elastic filament breakage and core voiding.

FIG. 3 shows another embodiment of a typical core spinning device 40. The elastic core I is a bare elastic filament 48, and the elastic core II 12 is pre-coated with an elastic yarn. The elastic core II from the bobbin 12 is unwound in the direction of the arrow 62 by the action of the forced drive feed roller 64. The weighting roller 66 serves to maintain a stable contact between the elastic core II and the feed roller 64 to convey the elastic core II of the yarn 68 at a predetermined speed. The other elements of Figure 3 are as described for Figure 2.

FIG. 4 shows another embodiment of a typical core spinning device 40. The elastic core I is a bare elastic filament 48, and the elastic core II 12 is pre-coated with an elastic yarn. The elastic core II from the bobbin 12 is wound from the end and then passed through the tension control device and the guide rod. The tensioning device functions to stably maintain the yarn tension at a predetermined level. The stretch ratio of the bare elastic fibers is usually 1.01X to 5.0X times (1.01X to 5.0X) as compared with the undrawn fiber. The other elements of Figure 4 are as described for Figure 2.

According to some embodiments of the method, two different elastic fibers are covered with hard fibers to form a composite yarn, wherein the two elastic fibers are stretched to different lengths of their original length during the yarn covering process . The drafting of the two elastic fibers can be selected between 1.01X times and 5.0X times drafting. For two kinds of elastic core fibers having different denier or different filament numbers, the stretch ratios of the elastic core I and the elastic core II may be different from each other, depending on the elastic fiber properties and the fabric quality requirements. In many cases, one core is stretched more to provide high tensile properties while the other core is stretched less to provide a fabric with low shrinkage and high restoring force.

In conventional fabrics, if the spandex is "set" using a heat setting process, the fabric can have high shrinkage, excessive fabric weight, and excessive elongation which can result in a negative experience for the consumer. Excessive shrinkage during the fabric finishing process can result in creases in the fabric surface during processing and home cleaning. The resulting creases are often extremely difficult to eliminate by ironing.

By using a low draft in one of the elastic core fibers, the use of a high temperature heat setting step in the process can be avoided. This new process reduces thermal damage to certain fibers (i.e., cotton) and thus improves the operability of the finished fabric. The fabric of some embodiments can be prepared without a heat setting step, including where the fabric is intended to be garmentd. For another benefit, heat-sensitive hard yarns can be used in the new process to make shirting and elastic fabrics, thereby increasing the likelihood of producing different and improved products. In addition, shorter processes are more productive for fabric manufacturers.

Surprisingly, it has been found that a core spun yarn having two different elastic core fibers has a higher stretchability and restoring power than a core spun yarn made of a single core elastic filament having the same Danny. For example, a core yarn with two cores (30d/3 filament spandex plus 40D/4 filament spandex) is under the same draft than a core yarn made from a single 70D/5 filament core. More resilience. Therefore, we can manufacture a core yarn having higher stretchability and higher resilience by using the same amount of spandex.

Two types of elastic fibers having different properties can be used and covered with a hard fiber sheath to form a composite yarn, wherein the two elastic fibers can have different polymer compositions and have different stress-strain behavior. One example is the simultaneous use of two spandex fibers having different heat setting efficiencies in a core spun yarn, such as standard LYCRA® spandex T162C and easy-set LYCRA® fiber T562B. The fabric can be heat set at temperatures above the heat set temperature of the LYCRA® fiber, but below the standard heat setting temperature of the LYCRA® fiber. Thus, the fabrics are only partially heat set, which provides acceptable fabric shrinkage while having good stretchability and growth.

Another example is a core yarn comprising an elastic core I having a high tensile modulus and an elastic core II having a low tensile modulus. The elastic core I provides high resilience and low fabric growth for the fabric, while the low modulus elastic core II makes the fabric easy to stretch and has low shrinkage, resulting in a fabric that is easy to stretch, has high retention, and is dimensionally stable. Elastomeric fibers having different chemical compositions may also be combined with a core spun yarn such as polyolefin elastic fibers Lastol and spandex. Spandex fibers provide high resilience, while Lastol fibers impart good heat resistance and low shrinkage.

The combination of the elastic core I and the elastic core II may be a bare elastic fiber plus a bare elastic fiber; or a bare elastic fiber plus a pre-covered elastic yarn or a pre-covered elastic yarn plus a pre-covered elastic yarn. The bare elastic fibers can be from about 11 dtex to about 444 dtex (Danny - about 10 D to about 400 D), including from 11 dtex to about 180 dtex (Danny 10D to about 162 D).

The pre-cover elastic yarn comprises various types such as: single winding with a hard yarn Elastomeric fiber; elastomeric fiber double-wound with a hard yarn; continuous covering of the elastomeric fiber with short fibers (ie, core-spun spinning), followed by kneading during winding; using an air nozzle to make the elastomer and the hard yarn The threads are intertwined and entangled; and the elastomeric fibers and the hard yarns are twisted together. Preferred pre-coated elastic yarns are spandex covered yarns of structured polyester and nylon filaments, such as 40D or 70D spandex air covered yarns having 50D to 150D polyester. The pre-coated elastic yarn is produced in a separate machine prior to the core-spun yarn process.

The pre-cover elastic yarn may be present in any desired amount, for example from about 5 to about 35 weight percent of the total double elastic yarn weight. The pre-covered yarn has a linear density in the range of from about 15 denier (16.5 dtex) to about 900 denier (990 dtex), including from about 30 denier to 300 denier (33 dtex to 330 dtex). When the yarn denier ratio of the pre-coated yarn to the total double elastic yarn is less than 35%, the fabric is substantially free of the bottom. After the finishing process, the two elastic core fibers (including the pre-coated yarn) are invisible and invisible.

The denier of the bare elastic fibers (before covering the pre-coated yarn) can be from about 11 dtex to about 444 dtex (Danny - about 10 D to about 400 D), including 11 dtex to about 180 dtex (Danny 10D to about 162 D). During the pre-covering process, the elastic fibers are drawn between 1.1 and 6 times their original length. In the pre-covering, the elastic fibers are pre-coated with one or more hard yarns, wherein the denier of the hard yarn is 10 to 600 denier.

Another combination of elastic core fibers I and elastic core fibers II may be a set of bare elastic fibers plus another set of non-elastomeric elastic fibers. The non-elastomeric elastic fibers can be structured PET stretch filaments, structured PPT stretch filaments, bicomponent fibers or PBT stretch fibers. Surprisingly, it has been found that when a non-elastomeric elastic fiber having a recoverability of more than 20% is used as one of the elastic core fibers, the properties of the core yarn and the fabric are significantly changed. These fabrics have high stretchability and high resilience. The linear density of the non-elastomeric elastic fibers can range from about 15 denier (16.5 dtex) to about 450 denier (495 dtex), including from about 30 denier to 150 denier (33 dtex to 165 dtex). When the Danny number is too high, the fabric can have substantially dew bottom.

The elastomeric fiber content of the bi-elastic core spun yarn is between about 0.1% and about 20%, including from about 0.5% to about 15% and from about 5% to about 10%, based on the weight of the yarn. The elastomeric fiber content in the fabric can range from about 0.01 to about 10% by weight, including from about 0.5% to about 5%, based on the total weight of the fabric.

The sheath staple fibers in the double elastic yarn may be natural fibers such as cotton, wool or linen fibers. They may also be the following artificial or synthetic staple fibers: one-component poly(ethylene terephthalate) and poly(trimethylene terephthalate) fibers, polycaprolactam fibers, poly(hexamidine) Hexamethylenediamine) fibers, acrylic fibers, modified polyacrylonitrile fibers, acetate fibers, Rayon fibers, nylon, and combinations thereof.

These double elastic yarns can be used to make stretch fabrics in which a variety of weave patterns can be applied, including plain weave, poplin, twill, oxford, jacquard, satin, satin, and combinations thereof. The fabric of some embodiments may have an elongation of from about 10% to about 45% in the warp or/and weft direction. These fabrics may have a shrinkage of about 15% or less after cleaning. The stretch woven fabric can have an excellent cotton hand. Garments can be made from the fabrics described herein.

The warp yarns may be the same as or different from the weft yarns. The fabric may only be stretched in the weft direction, or it may be biaxially stretched, with effective stretch and recovery properties in both the warp and weft directions.

Jet looms, sword looms, projectile looms, water jet looms and shuttle looms can be used. Dyeing and finishing processes are important in producing satisfactory fabrics. The fabric can be finished in a continuous process and a dye jet process. The conventional equipment found in continuous finishing plants and dyeing plants is usually sufficient for processing. The standard finishing sequence includes preparation, dyeing and finishing. Standard processing methods for elastic wovens are generally satisfactory during the preparation and dyeing process, including singeing, desizing, scouring, bleaching, mercerizing, and dyeing.

Analytical method:

Yarn can restore flexibility

The recoverable stretchability of the elastic fibers used in the examples was determined as follows. The various yarn samples were formed into a skein of 5000 +/- 5 (5550 dtex) total denier, with the skein reel at a tension of about 0.1 gpd (0.09 dN/tex). The skein was treated at 70 °F (+/- 2 °F) (21 °C +/- 1 °C.) and 65% (+/- 2%) relative humidity for at least 16 hours. The hank is suspended substantially vertically on the support, and a 6 mg/den (5.4 mg/dtex) weight (for example, 30 gram corresponding to 5550 dtex skein) is suspended at the bottom of the hank, allowing the load skein to reach an equilibrium length and measuring The length of the hank (accurate to 1 mm) is recorded as "C _b ". During the test, a 5.4 mg/dtex weight was left on the hank. Then, 1030 g weight (206mg / d; 185.4mg / dtex ) suspended from the bottom of the skein, and the skein length measurements (accurate to 1mm), and recorded as "L _b."

The 1030 g weight was removed and the hank was then immersed in boiling water (10 minutes in water at 100 ° C), after which the skein was removed from the water and treated as described above for 16 hours. This step is intended to simulate the commercial fabric relaxation process, which is a way to visualize the stretchability of the fabric. The length of the hank was measured as described above, and the length was referred to as "C _a ". The 1030 g weight was again hung on the hank and the skein length was measured as described above and recorded as "L _a ". The yarn recoverable stretchability (percentage) ("CC _a ") was calculated according to the formula CC _a = 100 x (L _a - C _a ) / L _a . The yarn shrinkage ratio was calculated according to the formula Cs (%) = 100 X (L _{b -} L _a ) / L _b .

Woven fabric elongation (stretchability)

The % elongation of the fabric in the direction in which the fabric is stretched, which is the direction of the composite yarn (i.e., the weft, warp or warp and weft), is evaluated under a specified load (i.e., force). Three samples of size 60 cm x 6.5 cm were cut from the fabric. The long dimension (60 cm) corresponds to the direction of stretching. The samples were partially unwrapped to reduce the sample width to 5.0 cm. The samples were then treated at 20 ° C +/- 2 ° C and 65% relative humidity +/- 2% for at least 16 hours.

A first datum was made along the width of each sample at 6.5 cm from the end of the sample. A second reference is made along the width of the sample at 50.0 cm from the first reference. A loop of metal needles can be formed and stitched with excess fabric from the second baseline to the other end of the sample. An incision is then made in the loop so that a weight can be attached to the metal needle.

The unformed end of the sample was clamped and the fabric sample was hung vertically. A 17.8 Newton (N) weight (4LB) was attached to the metal needle by a suspended fabric loop to stretch the fabric sample through the weight. The sample is "trained" by allowing the sample to be stretched by the weight for three seconds, and then the force is manually reduced by lifting the weight. This cycle is performed three times. The weight is then allowed to hang freely, thereby stretching the fabric sample. The distance (in millimeters) between the two references was measured while the fabric was under load and the distance was named ML. The initial distance between the references (ie, the unstretched distance) is named GL. The % elongation of the fabric for each individual sample is calculated as follows: % elongation (E%) = ((ML-GL) / GL) x 100

The average of the three elongation results is obtained to obtain the final result.

Woven fabric growth (unrecovered stretch)

After stretching, the fabric that has not grown will return to its original length before stretching. However, in general, the stretch fabric will not fully recover and will become slightly longer after long-term stretching. A slight increase in this length is called "growth."

The above fabric elongation test must be completed before the growth test. Only the direction of stretching of the fabric was tested. For two-way stretch fabrics, test both directions. Three samples were cut from the fabric, each 55.0 cm x 6.0 cm. These samples differ from their samples for elongation testing. The 55.0 cm direction should correspond to the direction of stretching. The samples were partially unwrapped to reduce the sample width to 5.0 cm. The samples were processed at the temperature and humidity as in the elongation test above. Two benchmarks that are exactly 50 cm apart are drawn along the width of the samples.

The length of the sample at 80% of the known elongation was calculated using the known % elongation (E%) from the elongation test. The calculation is as follows: E (length) at 80% = (E% / 100) x 0.80 x L, where L is the initial length between the references (ie, 50.0 cm). Clamp the ends of the sample and stretch the sample until the length between the references is equal to L + E (length) as calculated above. The stretching was maintained for 30 minutes, after which the pulling force was released and the sample was allowed to freely hang and relax. 60 After the minute, the % growth is calculated as follows: % growth = (L2 x 100) / L, where the length of the L2 sample sample is increased after relaxation, and the original length of the L system is between the benchmarks. The % increase in each sample is measured and the average of the results is determined to determine the growth value.

Woven fabric shrinkage

The shrinkage of the fabric after washing was measured. The fabric was first treated at the temperature and humidity as in the elongation and growth tests. Two samples (60 cm x 60 cm) were cut from the fabric. The samples were taken at least 15 cm away from the edge of the cloth. A 40 cm x 40 cm quadrilateral box was marked on the fabric samples.

The samples were washed in a washing machine with samples and loaded fabric. The total load of the washing machine is 2 kg of air-dried material, and no more than half of the washings are composed of test samples. Gently wash the laundry and rotate it at a water temperature of 40 °C. The amount of detergent used is from 1g/l to 3g/l, depending on the hardness of the water. The samples were placed on a flat surface until dry and then treated for 16 hours at 20 ° C +/- 2 ° C and 65% relative humidity +/- 2% rh.

The shrinkage of the fabric sample in the warp and weft directions was then measured by measuring the distance between the scribe lines. The shrinkage C% after washing was calculated as follows: C% = ((L1 - L2) / L1) x 100, where L1 is the original distance between the scribe lines (40 cm), and L2 is the distance after drying. The average of the results of the samples is obtained and recorded for both the latitude and longitude directions. The negative shrinkage value reflects the expansion, which may occur in some cases due to the behavior of the hard yarn.

Fabric weight

The woven fabric sample was punched out with a mold having a diameter of 10 cm. The weight of each cut woven fabric was weighed in grams. Then calculate the "fabric weight" in grams per square meter.

Example:

The following examples show the invention and its ability to make a variety of fabrics. The invention is capable of other and different embodiments, and may be Therefore, the nature of the examples should be considered as illustrative and not limiting.

For the following examples of denim fabrics, 100% cotton open-end spinning or ring spinning is used as the warp yarn. In the case of denim fabrics, it includes two yarn counts: a 7.0Ne OE yarn having an irregularly arranged pattern and an 8.5Ne OE yarn. The yarns are dyed in indigo in the form of a rope before warping. Then, it is sized and made into a braided shaft. In the case of heavy fabrics, the warp yarns are 20Ne 100% cotton ring spun yarns. It is sized and made into a braided shaft.

Table 1 lists four examples of a core yarn having a conventional elastic core filament and a novel yarn containing two sets of elastic cores.

A plurality of core yarns having a double elastic core fiber are used as the weft yarn. Various elastic core fibers (including bare spandex, pre-coated polyester/LYCRA® spandex or pre-coated nylon/spandex yarn) are used in the core. Table 2 lists the materials and processing methods used to make the core yarn of each example. Table 3 shows an overview of the fabric structure details and properties of each fabric. Lycra® is available from Invista, s.á.r.L., Wichita, KS. For example, in the spandex column, 40D means 40 Danny; 3.5X means the draft (machine draft) applied to the Lycra® by the core spinning machine. In the "Rigid Sheath" column, the linear density of the 20' spun yarn was measured by the English Cotton Count System. The remaining items in Tables 1 and 2 are clearly marked.

The stretch woven fabric was then produced using the core spun yarn of each of the examples in Table 2. Table 3 summarizes the quality characteristics of the yarns, weave patterns and fabrics used in the fabric. Some additional explanations regarding the examples are given below. Unless otherwise indicated, the fabrics were woven on a Donier jet or sword looms. The loom speed is 500 times per minute. The width of the fabric in the loom and in the state of the fabric is about 76 and about 72 inches, respectively. The loom has a dual braiding shaft capability.

The individual woven fabrics in these examples were prepared by a light shake dyeing machine. Each woven fabric was pre-cooked with 3.0 wt% Lubit® 64 (Sybron Inc.) for 10 minutes at 49 °C. Then, at Desizing with 6.0% by weight of Synthazyme® (Dooley Chemicals. LLC Inc.) and 2.0% by weight of Merpol® LFH (EI DuPont Co.) at 71 ° C for 30 minutes, then using 3.0% by weight of Lubit® 64 at 82 ° C. 0.5% by weight of Merpol® LFH and 0.5% by weight of trisodium phosphate for 30 minutes. After finishing the fabric, it was dried in a tenter at 160 ° C for 1 minute.

Example Yarn A: A typical core yarn with an elastic core fiber

This is a non-new yarn. The core yarn is 16Ne having a 40d LYCRA® spandex fiber covered by a cotton sheath. The drafting of LYCRA® fiber during the covering process is 3.5X. Cotton twist TM is 18 rpm. The yarn has 17.71% after desizing Retractability can be restored.

Example Yarn B: Core-spun yarn with two elastic core fibers

The core yarn is 16Ne having two sets of LYCRA® spandex fibers covered with a cotton sheath. The elastic core I fiber is 20D T162B, and the elastic core II fiber is also 20D T162B. The total Danny of the elastic fiber is 40 Danny. The drafting of LYCRA® fiber during the covering process is 3.5X. Cotton twist TM is 18 rpm. Thus, the core spun yarn has the same structure as the example yarn A except that two sets of core elastic filaments are used in place of one of the core yarns, including the yarn count, LYCRA® fiber denier and yarn twist. The recoverable stretch of the yarn was 20.63%, which was 2.92 unit percent higher than the yarn in Example A. This means that in the case of the same spandex content, yarns with two sets of filament cores have higher recoverability than yarns with a set of filament cores. In this way, the novel yarn can provide high stretchability and high resilience to the fabric by using the same amount of elastic fibers.

Example Yarn C: A typical core yarn with an elastic core fiber

This is a non-new yarn. The core yarn is 16Ne having a 70d LYCRA® spandex fiber covered by a cotton sheath. The drafting of LYCRA® fiber during the covering process is 3.8X. Cotton twist TM is 18 rpm. The yarn had a recoverable stretch of 38.71% after desizing and the yarn had a shrinkage of 2.28.

Example Yarn D: Core-spun yarn with two elastic core fibers

The core yarn is 16Ne having two sets of LYCRA® spandex fibers covered by a cotton sheath. The elastic core I fiber is 30D T162B, and the elastic core II fiber is 40D T162B. The total Danny of the elastic fiber is 70 Danny. The drafting of both LYCRA® fibers during the covering process was 3.8X. Cotton twist TM is 18 rpm. Thus, the core spun yarn has the same structure as the example yarn C except that two sets of core elastic filaments are used in place of a set of core spun yarns. The recoverable stretchability of the yarn was 40.88%, which was 2.17 unit percentages higher than the yarn sample C. This shows that in the case of the same spandex content, a yarn having two sets of filament cores has a higher recoverable stretchability than a yarn having a set of filament cores. In this way, The novel yarn provides high stretchability and high resilience to the fabric by using the same amount of elastic fibers.

Example 1: Typical stretch woven heavy fabric

This is not a comparative example according to the present invention. The warp yarn is a ring spinning of 40/2Ne count. The weft yarn is 20Ne cotton with 40D Lycra® core yarn. Lycra® is 3.5X. This weft yarn is a typical stretch yarn used in a typical stretch woven khaki fabric. The speed of the loom was 500 times/min, and the number of weft insertions was 56/inch. Table 3 summarizes the test results. The test results showed that the fabric had a weight (8.95 g/m ² ), a stretchability (37.6%), a width (50.5 inch), a weft wash shrinkage (0.91%), and a fabric growth (8.7%) after finishing. The data shows that this combination of stretch yarn and fabric construction causes a high growth of the fabric.

Example 2: Stretch fabric with bielastic fibers

This sample had the same fabric structure as in Example 1. The only difference is the use of a 20 s weft with a double elastic core fiber: 40D LYCRA® fiber with 3.5X draft and 40d LYCRA® fiber with 1.8X draft. The warp yarn is a 40/2Ne ring spinning cotton. The speed of the loom was 500 times per minute, 56 pieces per inch. Table 3 summarizes the test results. The results clearly show that the sample has similar stretch but has a lower fabric growth level (6.4%). Therefore, by using two kinds of elastic core fibers of different drafting in the same yarn, different characteristics can be obtained by covering the yarn and the fabric. For example, the high draw of the elastic core I fibers imparts high stretchability to the fabric, while the lower draw of the elastic core II fibers imparts low growth and high recovery to the fabric without increasing fabric shrinkage. In this way, a fabric having high stretchability, high recovery, and low shrinkage can be produced.

Example 3: Retractable fabric containing bielastic fibers

This example has a fabric structure as in Example 1. The only difference is the use of core yarn in the weft direction: 40D T162B LYCRA® fiber with 3.5X draft and 40d Easyset LYCRA® fiber with 3.5X draft. The warp yarn is 20Ne 100% cotton ring spinning. Use a 3/1 twill weave pattern. The finished fabric had a weight (9.19 g/m ² ), a 38.4% stretch and a 7.9% increase in the weft direction. The results clearly show that the Easyset LYCRA® fiber in the Elastic Core II maintains the degree of fabric stretch while reducing the fabric growth from 8.7% in Example 1 to 7.9%.

Easyset LYCRA® fibers can be heat set at about 170 ° C, which is about 20 ° C lower than the heat setting temperature of T162B LYCRA® fibers. Therefore, when the fabric is heat set at a temperature between 170 ° C and 190 ° C, the fabric is partially heat set. Only Easyset LYCRA® fibers are shaped and T162B is not finalized. In this way, the fabric maintains better stretchability and recovery while maintaining shrinkage to a certain extent.

Example 4: Stretch fabric with spandex and elastic polyolefin fibers

The warp yarn is a starting yarn of a mixture of a 7.0Ne count and a 8.4Ne count. The warp yarn is dyed in indigo before warping. The weft yarn is a 16Ne core yarn of 40D T162B Lycra® and 40D elastic polyolefin fiber. Lycra® fibers and elastomeric polyester fibers are stretched to 3.5X during the overlay process. Table 3 lists the properties of the fabric. The fabric made from such yarns exhibited a good cotton hand, good stretchability (47.8%) and good recovery (up 6.5%). All test results show that the combination of spandex and elastic polyolefin filaments produces good fabric stretch and growth. The fabric has no exposed bottom. Elastic filaments are not visible from both the fabric surface and the back of the fabric.

Compared with spandex, elastic polyolefin fibers or Lastol fibers have lower restoring power, but have better heat resistance, better chemical resistance, low fabric shrinkage and good cotton feel. Fabrics containing spandex and elastomeric polyolefins provide good stretchability and good recovery with better heat resistance, lower shrinkage and better chemical resistance, such as chlorine resistance in swimming pool and denim bleaching processes Sex.

Example 5: Stretch fabric with spandex and pre-coated elastic yarn

This example has a fabric structure as in Example 1. The difference is in the weft-up core yarn, which consists of a bare 40D LYCRA® fiber and a pre-coated elastic yarn (40D/34f nylon/40D Lycra® air-coated yarn) in the yarn core. The draft of the bare 40D LYCRA® fiber is 1.8X, and the draft of the LYCRA® fiber in the pre-coated elastic yarn is 3.2X. The weaving The same warp yarn and structure as in Example 1 were used. The weaving and finishing process is also the same as in Example 1. Table 3 summarizes the test results. It can be seen that the sample has good stretchability (35.9%), good weft wash shrinkage (0.65%) and good fabric growth (5.3%). The fabric has an excellent appearance and feel. After the addition of the pre-covered elastic yarn (40D/34f nylon/40D Lycra® fiber AJY yarn), the fabric growth was significantly reduced.

Example 6: Stretch fabric with spandex and pre-coated elastic yarn

This sample had a fabric structure as in Example 5. The only difference is the stretch of the bare 40D LYCRA® fiber during the covering process. The draft of the bare LYCRA® fiber was 3.5X, while in Example 5 it was 1.8X. The fabric weight was 8.96 OZ/yd ² and the weft elongation was 37.8%. The fabric has a very low latitudinal growth (5.9%). This example further demonstrates that the addition of an elastic composite yarn produces a high performance stretch fabric with low growth. The double elastic yarn reduced the fabric growth from 8.7% of Example 1 to 5.9%. The increased draw also produced higher weight and stretch than Example 5.

Example 7: Telescopic denim with spandex and pre-coated elastic yarn

This example has the same warp and fabric structure as in Example 4. The warp yarn is a starting yarn of a mixture of a 7.0Ne count and a 8.4Ne count. The warp yarn is dyed in indigo before warping. The weft yarn is a 16Ne core yarn of 40D Lycra® and 50D/24f polyester 40D LYCRA® fiber covered yarn. Lycra® is stretched to 3.5X and 1.8X in bare and composite cores. This example is a novel fabric. The speed of the loom was 500 times/min, and the number of wefts was 44/inch. Table 3 summarizes the test results. The test results showed that after washing, the fabric had a weight (12.80 OZ/Y ² ), a latitudinal stretch of 35.3%, and a latitudinal growth of 3.5%.

Example 8: Telescopic denim with spandex and pre-coated elastic yarn

This example has the same warp and fabric construction as in Example 7, except that the draft of the LYCRA® fiber in the pre-coated elastic yarn is different (2.6X draft in Example 8 and 1.8X draft in Example 7). Table 3 summarizes the test results. The results clearly show that the sample has good stretchability (40.4% in the weft direction) compared to sample 7.

Example 9: Stretch fabric with spandex and PBT stretch fibers

This example has the same warp and fabric construction as in Examples 7 and 8 except that 50D/26f PBT stretch fibers were used as the elastic core II fibers. The bare 50D/26f PBT fiber has a recoverability of 40.23% and a shrinkage of 3.44% (measured by the ASTM D6720 method). The stretch of the elastic core I Lycra® fiber is 3.5X during the covering process. Table 3 lists the properties of the fabric.

The fabric made from such yarns exhibited a good cotton hand, good stretchability (40.7%) and good recovery (6.0% growth). All test results show that the combination of spandex and non-elastomeric stretch filaments produces good fabric stretch and growth. The fabric has no exposed bottom; elastic filaments are not visible from both the fabric surface and the back of the fabric.

Claims (20)

An article comprising a core yarn comprising: a) a hard fiber sheath; b) a set of elastic fibers (elastic core fibers I); and c) another set of elastic fibers (elastic core fibers II); The elastic core fiber I and the elastic core fiber II have different elastic properties; wherein the elastic core fiber I and the elastic core fiber II comprise elastomer fibers selected from the group consisting of rubber filaments, elastomers (elastoester), and spandex A group of spandex and its combination. The article of claim 1, wherein the elastic core fiber I and the elastic core fiber II have different Dani numbers or different filaments. The article of claim 1, wherein the elastic core fiber I and the elastic core fiber II have different drafting properties. The article of claim 1, wherein the elastic core fiber I and the elastic core fiber II have different polymer compositions. The article of claim 1 wherein the at least one elastic core fiber comprises an elastomeric fiber having a Dani number of from about 10 denier to about 450 denier. The article of claim 5, wherein the at least one elastic core fiber comprises spandex fibers. The article of claim 1 wherein the at least one elastic core fiber comprises an elastomeric polyolefin fiber having a Dani number of from about 10 denier to about 450 denier. The article of claim 7, wherein the elastic polyolefin fiber is a lastol fiber. The article of claim 1 wherein the at least one set of elastic core yarns is pre-coated with an elastic yarn having a Danny number of from about 15 denier to about 300 denier. The article of claim 9, wherein the pre-cover elastic yarn comprises a group selected from the group consisting of Cover: air covered yarn, single wound yarn, double wound yarn and combinations thereof. The article of claim 9, wherein the pre-coated elastic yarn is a polyester and a spandex air covered yarn. The article of claim 1 wherein the at least one elastic core fiber comprises a non-elastomeric elastic fiber having a Danniic number of from about 15 to about 450 denier. The article of claim 1 wherein the non-elastomeric elastomeric yarn comprises at least one fiber selected from the group consisting of polyester, nylon, PTT fibers, PBT fibers, bicomponent fibers, and combinations thereof. The article of claim 1 wherein the hard fiber sheath is selected from the group consisting of wool, flax, silk, polyester, nylon, olefin, cotton, and combinations thereof. The article of any one of claims 1 to 14, wherein the article is a stretch fabric. The article of claim 15 wherein the fabric is a woven or warp knit or a circular knit. An article comprising a woven fabric having warp and weft yarns, wherein at least one of the warp yarns and the weft yarns comprises a core spun yarn comprising: a) a hard fiber sheath; b) a set of elastic fibers (elastic core fibers I) And c) another set of elastic fibers (elastic core fibers II); wherein the elastic core fibers I and the elastic core fibers II have different elastic properties; wherein the elastic core fibers I and the elastic core fibers II comprise elastomer fibers, The elastomeric fibers are selected from the group consisting of rubber filaments, elastomeric esters, spandex, and combinations thereof. The article of claim 17, wherein the fabric has a latitudinal stretch of from about 10 to about 45%. The article of claim 17, wherein the fabric comprises a garment. A method of manufacturing an article comprising a woven fabric having warp and weft The warp or weft yarn having a core yarn or both warp yarns and weft yarns having a core spun yarn, the method comprising covering the core spun yarn together, the core yarn comprising: a) a hard fiber sheath; An elastic core fiber I; and c) an elastic core fiber II; wherein the elastic core fiber I and the elastic core fiber II have different elastic properties; wherein the elastic core fiber I and the elastic core fiber II comprise an elastomer fiber, the elastomer The fibers are selected from the group consisting of rubber filaments, elastomeric esters, spandex, and combinations thereof.