EP1699956A1

EP1699956A1 - Fabric formed from a largely untwisted yarn

Info

Publication number: EP1699956A1
Application number: EP20040806776
Authority: EP
Inventors: Govindaswamy Kannappan
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-12-30
Filing date: 2004-12-29
Publication date: 2006-09-13
Also published as: CA2551280A1; AU2004309180A1; JP2007517144A; WO2005064056A1; US20050142972A1

Abstract

Presented is a fabric (20) comprised of a staple fiber yarn exhibiting a twist multiplier of less than a prescribed value, preferably 1.5. Yarn (10) is formed from staple fibers twisted together with a certain number or twists-per-inch. The twist-per-inch of the yarn in the fabric is related to the yarn count and a proper balancing of the two results in a twist multiplier of preferably less than 1.5. The Yarn Count is indirectly related to the fiber diameter. The fabric embodying the present invention has a softer more luxurious feel, more bulk, and greater absorbency than a conventional fabric.

Description

FABRIC FORMED FROM A LARGELY UNTWISTED YARN

Field of Invention The present invention concerns fabrics that are produced with a

yam 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 yam used in the manufacturing process. The

properties of the yam 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 yams 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 yam, the more the number of threads per square-inch. Yams 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 yam 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 yam is intermeshed

with a second yam by joining loops formed from the two yams. The fibers of at

least the first yam 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 yam and the diameter of the fibers. In accordance with yet another aspect of the present invention, a

woven fabric comprises a first yam formed from staple fibers. The first yam is

perpendicularly interlaced with a second yam to form a matrix, where the first

yam can be both a weft yam and a warp yam. The fibers of at least the first yam

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 Figure 1 is a perspective view of a yam which embodies the

present invention; and

Figure 2 is a perspective view of a woven fabric with an

exaggerated weave comprised of the yam depicted in Figure 1.

Detailed Description of the Illustrative Embodiments By way of overview and introduction, provided is a fabric structure

in which the yams 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 yam 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 yam fibers are thus harnessed to result in a highly

lustrous fabric that is very soft, smooth and absorbent. Yam is converted to fabric by processes, commonly weaving or

knitting, which require the yam to have sufficient strength to withstand the

stresses and strains involved in the manufacturing process. Conventionally, yam

produced from staple fibers requires a high degree of twist to help the fibers hold

on to one another and provide strength to the yam. A yam formed without

twisting the fibers will not have the strength to be useful in making a fabric.

Conventional fabrics comprise yams 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 yams 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)/(Λ/Yarn Count(English)) [Eq.

1]

The twist-per-inch is the actual amount of twist provided to the

fibers in the yam. Typically, when yam is manufactured, there is a certain

amount of twist given to the fibers depending on its Yam Count. Yam Count

(English), commonly represented as Yam Count (Ne), is the number of 840 yards

of the yam that weighs one pound. Yam count is an indication of the yam's

diameter. Therefore, to compare the twist levels between yams of different Ya

Counts, the Twist Multiplier (TM) is considered rather than the actual twist-per-

inch (TPI).

There are a number of standards for measuring Yam Count (e.g.,

English Count (Ne), French, Metric, Worsted, Denier, etc.) Conversion from one

system of measuring Yam 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 yam's diameter — the higher the Ne

value, the smaller the diameter of the yam.

By way of example, for a yam with a yam count of Ne 40s there

would be 40 x 840 = 33,600 yards of yam in one pound. Similarly, a yam with a

60s Ne yam count would have 60x840 = 50,400 yards in one pound. This

example shows that for the same material the 60s Ne yam weighs less per unit

length compared to the 40s Ne yam, meaning the 60s Ne yam diameter is smaller

than the 40s Ne yam diameter.

All predominant types of fabrics (woven, knitted, etc.) can be made

to have a yam 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 yam having a typical

twist multiplier of greater than three.

Figure 1 depicts a yam 10 formed from strands of fibers. The

fibers have been twisted together, say in the direction of arrow A, to form a yam

with a certain number of turns-per-inch (TPI). As an example, for a 40s Ne Yam

Count, a twist multiplier of 1.5 will yield a twist level of about 9.5 TPI. The

structure of the yam and its twisted fibers are shown in magnified view in Figure 1, where the individual fibers are apparent. Yam 10 can comprise a cotton yam. As used herein, the term

"yam" 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 yam is composed of many non-continuous and rather short

fibers called staple fibers. To overcome fiber slippage and to define a functional

yam, staple fibers are usually given a great amount of twist or entanglement.

The process of yam making consists of converting a stock of fibers

into a yam 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

yam.

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 yam. 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 yam, during manufacture a

twist is imparted to the yam 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 yam. The TPI for a specific fiber is determined by the count, the fiber

properties (particularly length and diameter), and the purpose for which the yam

is to be used. A clockwise or counterclockwise twist can be imparted to the yam.

The yam 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 yam stmcture. The fibers of yam 10 exhibit a substantially reduced twist

compared to the twist exhibited by conventional yams. 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 yam

stmcture similar to yam 10. Knitting is a method of converting yam 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 yam called the

warp yam and the weft yam. The warp and weft yams 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, Figure 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.

Figure 2 illustrates fabric 20 with an exaggerated weave to more

clearly illustrate yam 10. Fibers of the yam have been arranged in a more

parallel manner and have a twist multiplier of less than 1.5.

The fabric 20, composed of yam 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'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.

Claims

I claim:

1. A knitted fabric comprising: at least a first yam made of staple fibers; the first yam and a second yam being intermeshed to form a

matrix; the matrix composed of loops formed from the first yam and the

second, wherein the loops are joined together; and at least the first yam is a yam having a twist multiplier of less than

about 1.5.

2. The knitted fabric of claim 1, wherein the fabric is one of a warp

knitted fabric and a weft knitted fabric.

3. The knitted fabric of claim 1, wherein the fabric is a processed fabric;

and the fabric bears the result of at least one of a mercerizing processj a

dye process, a bleach process, and a print process.

4. The knitted fabric of claim 3, wherein the processed fabric comprises a

finishing effect; and wherein the finishing effect imparts physical properties to

the fabric.

5. The knitted fabric of claim 1, wherein at least the first yam comprises

one of cotton and any other staple fiber.

6. A woven fabric comprising: at least a first yam made of staple fibers; the first yam and a second yam being interlaced to form a matrix

comprised of a warp yam and a weft yam, which are about perpendicular to one

another; and at least the first yam is a yam having a twist multiplier of less than

about 1.5; wherein the first yarn is one of the warp yam and the weft yam.

7. The woven fabric of claim 6, wherein the fabric is a processed fabric;

and the fabric bears the result of at least one of a mercerizing process, a

dye process, a bleach process, and a print process.

8. The woven fabric of claim 7, wherein the processed fabric comprises a

the fabric.

9. The woven fabric of claim 6, wherein at least the first yam comprises

one of cotton and any other staple fiber.