Patent Publication Number: US-2005142972-A1

Title: Fabric formed from a largely untwisted yarn

Description:
CLAIM OF PRIORITY  
      This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 60/533,603, filed Dec. 30, 2003, titled “FABRIC FORMED FROM A LARGELY UNTWISTED YARN” hereby incorporated by reference in its entirety. 
    
    
     FIELD OF INVENTION  
      The present invention concerns fabrics that are produced with a yarn having staple fibers in a largely untwisted manner. A fabric with such a structure has a smoother contour which results in an extremely soft fabric as compared to the same fabric made with a conventionally twisted yarn.  
     BACKGROUND OF THE INVENTION  
      The characteristics of fabric produced by knitting or weaving operations is dependent of the yarn used in the manufacturing process. The properties of the yarn used to form the fabric affect the physical characteristics of a fabric (e.g., texture, softness, body, and absorbency). The most common yarn used in making fabrics is formed from staple fibers that are highly twisted together. However, highly twisting together staple fibers negatively impacts the desirable characteristics of the fabric.  
      Fabrics used for clothing, bedding, and bath products have always demanded a higher degree of texture, softness, body, and absorbency. Prior to the present invention very fine fibers were used to form yarns from which fine fabrics are constructed. The quality of the fine fabric being indicated by the number of threads per square inch (Thread Count) in the fabric; where a higher Thread Count indicates a finer fabric. The finer the yarn, the more the number of threads per square-inch. Yarns formed from fine fibers are more expensive, and require more intricate machinery to be worked into fabrics.  
      What is needed in the art is a fabric produced with a yarn which is largely untwisted, so as to impart desirable characteristics to the fabric. The present invention satisfies this and other needs, as set forth in the following description.  
     SUMMARY OF THE INVENTION  
      In accordance with one aspect of the invention, a knitted fabric comprises a first yarn formed from staple fibers. The first yarn is intermeshed with a second yarn by joining loops formed from the two yarns. The fibers of at least the first yarn are arranged in a parallel manner to result in a twist multiplier of less than 1.5. The twist multiplier is related to the turns-per-inch of the fibers forming the yarn and the diameter of the fibers.  
      In accordance with yet another aspect of the present invention, a woven fabric comprises a first yarn formed from staple fibers. The first yarn is perpendicularly interlaced with a second yarn to form a matrix, where the first yarn can be both a weft yarn and a warp yarn. The fibers of at least the first yarn are arranged in a parallel manner to result in a twist multiplier of less than 1.5.  
      These and other aspects, features, steps and advantages can be further appreciated from the accompanying drawing Figures and description of certain illustrative embodiments. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES  
       FIG. 1  is a perspective view of a yarn which embodies the present invention; and  
       FIG. 2  is a perspective view of a woven fabric with an exaggerated weave comprised of the yarn depicted in  FIG. 1 . 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS  
      By way of overview and introduction, provided is a fabric structure in which the yarns are staple fibers that are in a largely untwisted manner, i.e., exhibiting a twist multiplier of a prescribed value, preferably less than 1.5. The fabric is comprised of yarn fiber that are conventional staple fibers which are combined together in a largely untwisted, almost parallel manner. By maintaining the fibers in an almost parallel arrangement it is possible to impart favorable characteristics for texture, softness, body, and absorbency to the fabric. The natural properties of the yarn fibers are thus harnessed to result in a highly lustrous fabric that is very soft, smooth and absorbent.  
      Yarn is converted to fabric by processes, commonly weaving or knitting, which require the yarn to have sufficient strength to withstand the stresses and strains involved in the manufacturing process. Conventionally, yarn produced from staple fibers requires a high degree of twist to help the fibers hold on to one another and provide strength to the yarn. A yarn formed without twisting the fibers will not have the strength to be useful in making a fabric. Conventional fabrics comprise yarns with a minimum level of twist; e.g., a twist multiplier of about 3 and above.  
      Textile fibers are characterized by their linear structure. When the fibers are twisted, the uniformity of their surface is lost, along with some of the more desirable properties like luster, softness, absorbency, etc. To be able to retain these favorable properties, the fibers would have to be in a largely untwisted manner. Such an untwisted bunch of fibers would not have the sufficient strength to withstand the processes of fabric making.  
      A fabric which embodies the present invention improves upon conventional fabrics having fine fibers to impart the desirable properties to fabric. Embodying fabrics impart large degrees of the desirable properties of texture, softness, body, and absorbency through yarns which are in a largely untwisted manner—almost parallel to each other. Because the fibers are in an almost parallel arrangement, their natural properties can be harnessed to the maximum resulting in a highly lustrous fabric that is very soft, smooth, and absorbent.  
      Staple fibers with a twist multiplier of less than 1.5 comprise a fabric embodying the invention. Twist multiplier is defined by the following formula: 
 
Twist Multiplier=(Twist-per-inch)/({square root}Yarn Count(English))  [Eq. 1]
 
      The twist-per-inch is the actual amount of twist provided to the fibers in the yarn. Typically, when yarn is manufactured, there is a certain amount of twist given to the fibers depending on its Yarn Count. Yarn Count (English), commonly represented as Yarn Count (Ne), is the number of 840 yards of the yarn that weighs one pound. Yarn count is an indication of the yarn&#39;s diameter. Therefore, to compare the twist levels between yarns of different Yarn Counts, the Twist Multiplier (TM) is considered rather than the actual twist-per-inch (TPI).  
      There are a number of standards for measuring Yarn Count (e.g., English Count (Ne), French, Metric, Worsted, Denier, etc.) Conversion from one system of measuring Yarn Count to another is possible, but for calculating Twist Multiplier using Equation 1, the count is in the English system (Ne). The English count is indirectly related to the yarn&#39;s diameter—the higher the Ne value, the smaller the diameter of the yarn.  
      By way of example, for a yarn with a yarn count of Ne 40s there would be 40×840=33,600 yards of yarn in one pound. Similarly, a yarn with a 60s Ne yarn count would have 60×840=50,400 yards in one pound. This example shows that for the same material the 60s Ne yarn weighs less per unit length compared to the 40s Ne yarn, meaning the 60s Ne yarn diameter is smaller than the 40s Ne yarn diameter.  
      All predominant types of fabrics (woven, knitted, etc.) can be made to have a yarn having a twist multiplier less than or equal to 1.5. Such fabrics can be further processed by any conventional method including, but not limited to, dyeing, bleaching, printing, and finishing. The fabric embodying the present invention can present a smoother contour which results in an extremely soft fabric as compared to a fabric made with a conventional yarn having a typical twist multiplier of greater than three.  
       FIG. 1  depicts a yarn  10  formed from strands of fibers. The fibers have been twisted together, say in the direction of arrow A, to form a yarn with a certain number of turns-per-inch (TPI). As an example, for a 40s Ne Yarn Count, a twist multiplier of 1.5 will yield a twist level of about 9.5 TPI. The structure of the yarn and its twisted fibers are shown in magnified view in  FIG. 1 , where the individual fibers are apparent.  
      Yarn  10  can comprise a cotton yarn. As used herein, the term “yarn” has its conventional meaning and refers to a single fiber, or alternatively a linear assemblage of fibers, formed into a continuous strand, having textile-like characteristics. The yarn is composed of many non-continuous and rather short fibers called staple fibers. To overcome fiber slippage and to define a functional yarn, staple fibers are usually given a great amount of twist or entanglement.  
      The process of yarn making consists of converting a stock of fibers into a yarn whose composition, color, count, and twist are specified. Irrespective of differences in machinery used for different fibers, the following discussion illustrates conventional operations that are fundamental to the process of making yarn.  
      If necessary, opening, cleaning, and mixing is done in conventional opening and cleaning machines to prepare the fiber. After preparation, the fiber is then formed into a sliver on a carding machine. To form a sliver, an input feed of fibers is highly separated (almost to a single fiber formation on the card) so that the fibers can be reassembled with side by side orientation. Fibers issue from the carding machine as a fine web. This web is gathered together and passes through a funnel from which it then issues in rope-like form as a sliver. At this stage the sliver still must be reduced in subsequent processes to yield the desired thickness required for a particular yarn.  
      The sliver is reduced by a drafting process which attenuates the sliver. Card sliver has many thousands of fibers in its cross section, whereas most single yarns are desired to have only about one hundred or fewer fibers in cross section. The sliver must therefore be attenuated, or drawn finer, and this is done by passing it through drafting rollers. The simplest arrangement consists of two pairs of rollers through which the sliver is passed. Drafting results in attenuation of the sliver, and parallelization of fibers as a result of drawing the sliver to a smaller cross section.  
      To prevent fiber slippage in rovings and yarn, during manufacture a twist is imparted to the yarn in a given direction (either clockwise or counterclockwise). When the strand of fibers has been reduced, say, to a specified linear density, it must be given sufficient strength to enable it to be fabricated into a cloth of some kind. This is traditionally accomplished by twisting the yarn.  
      The TPI for a specific fiber is determined by the count, the fiber properties (particularly length and diameter), and the purpose for which the yarn is to be used. A clockwise or counterclockwise twist can be imparted to the yarn. The yarn produced is typically wound on some form of package to enable it to be stored and transported in a tidy and convenient way. Such packaging has no effect on the yarn structure.  
      The fibers of yarn  10  exhibit a substantially reduced twist compared to the twist exhibited by conventional yarns. The fibers are arranged in a more parallel manner and are billowed, or less tightly wound.  
      Knitted fabrics or woven fabrics can be made to have a yarn structure similar to yarn  10 . Knitting is a method of converting yarn into fabric by intermeshing loops, which are formed with the help of needles. There are two basic forms of knitting technology, weft and warp knitting. Weft knitted fabrics can be produced in either flat or tubular form with the work progressing width-wise. In warp knitted fabrics, the work progresses length-wise.  
      Weaving is the process of interlacing two sets of yarn called the warp yarn and the weft yarn. The warp and weft yarns are perpendicular to one another. The longitudinal threads are termed as ‘warp’ and the transverse threads running from one selvedge to the other selvedge of the fabric are termed ‘weft’.  
      The knitted or woven fabric  20 ,  FIG. 2 , is now ready for processing and finishing to make it ready for cutting and sewing. The different processing processes include mercerizing, bleaching, dyeing, printing, finishing, etc. Dyeing is the process through which molecules imparting color are chemically bonded to fibers. In the dyeing process, the engineered fabric is impregnated with the dyestuff. In the printing process, a pattern or design is generally imprinted on the fabric in one or more colors by using dyes in paste form or some other related form. Printing color designs on dyed fabrics further enhances the finished cloth to add additional beauty and appeal.  
      The finishing process is the final step in producing fabrics and typically imparts aesthetic and physical properties required for the various fabric uses. These properties, achieved through a combination of chemical and mechanical processes, include shrinkage control, stain resistance, water repellency, and softness. Dyed or printed fabrics are transferred to the finishing process where they undergo various processes. Some finishes are applied wet, some dry, some are cold and some are heated treatments. Often a combination of methods is used to complete the finishing process.  
       FIG. 2  illustrates fabric  20  with an exaggerated weave to more clearly illustrate yarn  10 . Fibers of the yarn have been arranged in a more parallel manner and have a twist multiplier of less than 1.5.  
      The fabric  20 , composed of yarn  10  is processed in a conventional manner. Known as processing and finishing, these processes ready the fabric for cutting and sewing. Processing, bleaches the knit or woven engineered fabric. Dyes are impregnated into the engineered fabric and prints are imprinted on the surface to enhance the fabric&#39;s eye appeal. Finishing, is the final step in fabric production and it imparts aesthetic and physical properties to the fabric by a combination of chemical and mechanical processes. These properties include shrinkage control, stain resistance, water repellency, and softness.  
      Thus, while there have been shown, described, and pointed out fundamental novel features of the invention, it will be understood that various omissions, substitutions, and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit and scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale, but that they are merely conceptual in nature. The invention is defined solely with regard to the claims appended hereto, and equivalents of the recitations therein.