WO2001021299A1

WO2001021299A1 - Opaque heat-moldable circular knit support fabrics having very high spandex content

Info

Publication number: WO2001021299A1
Application number: PCT/US2000/025037
Authority: WO
Inventors: James Martin Miller; Arlis Steven Hall; Harry James Mccarter; Larry Herbert Stephens
Original assignee: Milliken & Company
Priority date: 1999-09-20
Filing date: 2000-09-13
Publication date: 2001-03-29
Also published as: EP1085115A3; EP1085115A2; AU7375400A

Abstract

This invention relates to support garments which comprise opaque heat-moldable circular knit fabrics (10 and 20) having relatively high amounts of spandex material (22) as well as sufficient amounts of other fibers (24 and 26) to simultaneously provide maximum support and maximum comfort to a wearer and which can be easily molded to the specifications of a wearer's body dimensions. Such high-spandex content, moldable garment fabrics (10 and 20) are novel to the industry since the permissible added amount of spandex (22) within such fabrics (10 and 20) has been limited due to the power, modulus strength, and elongation of such fibers. The method of producing such fabrics (10 and 20) is also contemplated within this invention.

Description

Disclosure

OPAQUE HEAT-MOLDABLE CIRCULAR KNIT SUPPORT FABRICS

HAVING VERY HIGH SPANDEX CONTENT

Technical Field

This invention relates to support garments which comprise opaque heat-

moldable circular knit fabrics having relatively high amounts of spandex material as

well as sufficient amounts of other fibers to simultaneously provide maximum support

and maximum comfort to a wearer and which can be easily molded to the

specifications of a wearer's body dimensions. Such high-spandex content, moldable

garment fabrics are novel to the industry since the permissible added amount of

spandex within such fabrics has been limited due to the power, modulus strength, and elongation of such fibers. Furthermore, the ability to provide moldable, high-spandex

circular knit fabrics has been limited, if not impossible, due to the above-noted

characteristics of the spandex fibers themselves. Thus, the incorporation of such

moldable fabrics within certain support garments (such as brassieres, girdles, medical

braces, athletic supporters, and the like) has been unsuccessful in the past. The

inventive moldable fabrics and garments provide such desirable spandex properties

while also increasing the comfortability to the wearer. The method of producing such

fabrics is also contemplated within this invention. Background of the Prior Art

Support garments have been utilized for centuries to provide methods of keeping body parts stationary (such as with knee braces), alleviating discomfort and/or

making fashion statements (such as with brassieres, including sports bras),

constraining certain areas of a person's body in order ultimately to provide an

aesthetically pleasing figure (such as with girdles and the like), protecting particularly

susceptible body parts from harm (such as with athletic supporters), and the like.

Myriad ways of providing such methods have been developed in the past. For

instance, braces have been produced which utilize high tensile strength/low elongation

fibers, metal components, and cast materials. Brassieres and girdles have been fashioned from certain fabric configurations, metal wires, and, again, high tensile

strength/low elongation fibers. Added padding and/or high tensile strength/low

elongation fibers have been utilized to improve upon existing athletic supporter

garments as well. In each of these examples, the improvements have focused on

adding cumbersome and potentially uncomfortable metal wires or extra material within the body of the garment, utilizing high tensile strength fibers in high amounts,

or utilizing strips of the garment fabric placed at specific angles, all in order to

provide the requisite and desired support. Nor have these past garment and/or fabric

developments have generally not been available as moldable articles which can be

modified to conform to a wearer's body dimensions. As such, there is a need to produce a moldable fabric which provides the necessary level of support for such

garments with a simultaneous increase in comfort for the wearer. High modulus fibers, such as spandex, have been introduced in the past within woven and knit fabric constructions in order to provide increased power, elongation,

and thus support within such garments. However, an increase in the amount of

spandex has invariably reduced the comfort level due to the highly constrictive power of such high spandex-content fabrics. In particular, circular knit fabrics have been

extremely difficult to create which comprise high amounts of spandex (greater than

24%) and which are sufficiently comfortable to the wearer. Circular knits are highly

desirable as support garments and permit more efficient jet-dyeing procedures through

the production of curl-susceptible (i.e., elastomeric fiber-containing) fabrics in tubular

form. Jet dyeing provides a simplified and effective method of coloring fabrics

quickly and evenly. Thus, in an effort to more efficiently produce such support

garment fabrics, the ability to utilize jet dyeing techniques would reduce cost by more

thoroughly and evenly coloring the target fabrics. Consistency in colorations for large

amounts of fabrics would thus be more easily and inexpensively achieved. Warp-knit fabrics comprising curl-susceptible fibers are not produced in tubular form; instead

they are formed as webs. Thus, in order to permit proper jet-dyeing of such fabrics,

the edges of such webs must be attached by gluing, sewing, and the like, and

subsequently split apart in order to properly permit jet-dyeing. Such a time-

consuming and labor-intensive procedure is therefore unacceptable, particularly for

curl-susceptible fabrics for which circular knit constructions are desired. Thus, there

is a clear need to produce high spandex-content circular knit fabrics which can be jet-

dyed in knitted tubular form. Such high spandex-content circular knit fabrics have heretofore been unexplored. Furthermore, circular knits are more easily stitched to conform with specific shapes and configurations in order to provide comfort to a

wearer as well. Thus, circular knit fabrics which comprise large amounts of spandex

are highly desirable within the industry; unfortunately, as noted above, the incorporation of such high amounts of spandex have proven too difficult to provide

the desired comfort level and simultaneous support function. The prior art has not

accorded the industry with any teaching to accomplish this desired task. As such,

there is still a need to develop a circular knit fabric having a high spandex content

(above 24% of the total weight of the fabric) which comprises other fibers to provide comfort to the wearer.

Description of the Invention

It is thus an object of the invention to provide such improved high-density (opaque) heat-moldable support for a wearer's body parts (such as an injured knee

joint, a woman's breasts, and the like) within a garment through the utilization of a

specific circular knit fabric comprising relatively high amounts of spandex fibers. A

further object of the invention is to provide a comfortable, functional support garment

made from circular knit fabrics of high spandex content. Another object is to provide

a support garment which possesses suitable flexibility for placement on and around a

target body part and provides excellent support upon placement at the target location.

Still a further object of the invention is to provide a method for producing such a high

spandex-content circular knit support garment fabric. Accordingly, this invention encompasses an opaque heat-moldable circular

knit fabric comprising at least two different types of fibers, wherein one type is

spandex, wherein said spandex is present in an amount of at least 24% of the total weight of fabric, and wherein at least one non-spandex-containing float per repeated knit pattern is present within the knit fabric. Furthermore, this invention also

concerns a method of forming an opaque heat-moldable, circular knit fabric

comprising at least 24% of spandex yarns by weight of the fabric, said method

comprising the steps of:

(a) providing at least one thread of spandex fiber;

(b) delivering said thread to a needle bed under constant tension;

(c) feeding said thread into a needle bed while simultaneously elongating said thread to at least 100% of its total stretch capability;

(d) introducing said elongated spandex thread within a carrier fabric comprising at least one fiber selected from the group consisting of polyamide,

polyester, cotton, wool, ramie, acetate, polyurethane, and any blends thereof;

(e) pulling said spandex thread into the loop construction of said circular

knit fabric; and

(f) knitting at least one non-spandex-containing float per repeated knit

pattern into the fabric structure. Further steps to produce a support garment

comprising such an inventive fabric would include

(g) incorporating the circular knit fabric into a garment (such as through sewing, adhering, and the like); and (h) heat-setting the garment of step "g" in a pre-selected orientation.

Nowhere within the prior art has such a specific fabric, support garment, or method of producing the same been disclosed or fairly suggested. There is no specific teaching or even implication, however, within the prior art concerning circular knit fabrics

which comprise at least 24% spandex fibers. Nor is there any discussion of the

problems inherent with introducing such a large amount of powerful spandex fibers within a circular knit construction, particularly when moldability, and consequently,

comfort are the primary concerns for the wearer. Additionally, there is no teaching or

fair suggestion within the prior art even remotely concerning any manner of fulfilling

the need for high spandex fiber content in support garments, while simultaneously

according the wearer heat-moldability and thus comfort as well. The inventive circular knit fabrics utilized within such support garments contain such high spandex

fiber content and provide concurrent comfort to the wearer. The introduction of high

amounts of spandex within circular knits have not been possible without sacrificing

comfort (and thus wearability). Circular knits, as discussed above, are highly

desirable as support garments, permit more efficient jet-dyeing procedures as

compared with other knit fabrics, and are more easily stitched to conform with

specific shapes and configurations in order to provide maximum comfort to a wearer.

The closest prior art, U.S. Patent 5,359,732 to Waldman et al., discusses the

production of garments comprising potentially knit fabrics having a spandex content

of at most 20%. However, there is no disclosure or fair suggestion that a circular knit construction is favored or even possible within patentees' fabrics. Furthermore, U.S. Patent 4,467,595 to Kramers discloses the incorporation of spandex fibers within composite yarns. However, Kramers fails to teach, and actually diverges from, the

same current inventive methods and fabrics since the ability to incorporate such

spandex content cannot be achieved through elongation or constant, consistent tension

application on all of the knit yarns. Lastly, there is no discussion of the potential for circular knit fabrics made from such composite yarns anywhere within Kramers

teachings.

The term "support garment" is intended to encompass any textile utilized on a

person's body for the purpose of providing support to, keeping stationary, and/or

protecting a particular body part or parts. Included in this description are brassieres,

most notably, but not limited to, sports bras; medical braces, such as for knees or elbows, as merely examples; support underwear, such as "control-top" panties and

hosiery; and athletic supporters (i.e., jock straps). Again, this list merely describes

preferred embodiments of the inventive support garment and by no means is intended

to limit the scope of the invention.

At the very least, two different fibers must be present within the inventive

fabric (any number of blends, other fibers, etc., may be present as well; the minimum

number of fibers present is two). One must be spandex; however, the other may be of

any type, as long as it is not spandex itself. Polyester and polyamide are most

preferred; however, any natural fibers, such as cotton, ramie, and the like; any other synthetic fibers, such as polyurethanes, acrylics, and the like; and any blends thereof

of any natural and/or synthetic fibers may be utilized within the inventive fabric, such as cotton/polyester and polyester/nylon blends. Of particular interest are fabrics which possess suitable weights for incorporation within flexible support garments. As

merely examples, weights of fabric in the range of between 2.0 and 12.5 ounces per square yard are preferred with more preferred possessing weights of 3.5 to about 10.5

ounces per square yard. Also, the permissible deniers of such other fibers range from

about 10 to about 1,000, with 20 to about 700 more preferable, and from about 70 to

about 200 most preferable. Furthermore, synthetic fibers may be present in filament

form in any count; however, counts ranging from about 1 to about 100 are preferred, 5

to about 80 more preferred, and from about 20 to about 70 most preferred.

One preferred type of spandex is available from DuPont under the tradename

Lycra®; however, any type of spandex may be utilized within this inventive fabric.

The range of permissible deniers for such fibers is from about 1 to about 1,000;

preferably from about 5 to about 700; more preferably from about 50 to about 200;

and most preferably from about 100 to about 140. One preferred type of spandex is that which may elongate, at the least, to about 100% of its relaxed length. Again, at

least 24%) by weight of the target fabric should constitute some form of spandex in

order to provide the required power in the fabric (for the required support functions).

Any other standard textile additives, such as dyes, pigments, hydrophobic agents (i.e., fluorocarbons), sizing compounds, and softening agents may also be

incorporated within or introduced onto the surface of the target fabric after or

incorporated within the constituent fibers prior to production. Particularly desired as

optional finishes to the inventive fabrics are soil release agents which improve the wettability and washability of the fabric. Preferred soil release agents include those

which provide hydrophilicity to the surface of polyester. With such a modified

surface, again, the fabric imparts improved comfort to a wearer by wicking moisture. The preferred soil release agents contemplated within this invention may be found in

U.S. Patents 3,377,249; 3,540,835; 3,563,795; 3,574,620; 3,598,641; 3,620,826;

3,632,420; 3,649,165; 3,650,801; 3,652,212; 3,660,010; 3,676,052; 3,690,942;

3,897,206; 3,981,807; 3,625,754; 4,014,857; 4,073,993; 4,090,844; 4,131,550;

4,164,392; 4,168,954; 4,207,071; 4,290,765; 4,068,035; 4,427,557; and 4,937,277.

These patents are accordingly incorporated herein by reference. The inventive fabric

preferably comprises such soil release agents in order to wick moisture from the

wearer (as another way of providing comfort), particularly, and primarily when the constituent fibers are spandex and the preferred polyester.

Such an inventive fabric also provides the benefit of heat-moldability to the

dimensions of a wearer. The yarns themselves will stretch to a certain orientation

upon placement of the fabric into a garment and fitting the resultant garment to at least

a portion of the body of a wearer. At that point, the fabric may then be heat-set to

retain the specific body-dimension yarn orientation in order to provide continued and

consistent comfortability for the wearer. The yarns, upon stretching, can thus be set

into specific positions upon exposure to the temperature (which is highly dependent

upon the type of fibers present; for example, if polyester or polyamide, such as nylon,

is utilized, the heat-set temperature is from about 162 to about 210°C) required to melt

the constituent yarns into their most relaxed positions when stretched to the wearer's body dimensions, and then cooled, in order to retain the desired yarn and fabric

orientation. This benefit is most pronounced when all synthetic yarns are knitted into

the inventive fabric structure.

The desired and required degree of opacity possessed by the inventive fabric is

provided by the addition of floats (i.e., yarns oriented transversely from the remaining

stitch pattern) within the circular knit structure. These floats increase the density of

the fabric and pervade discrete areas within the knitted fabric in which generally no fibers are present. By so doing, these floats provide cover to very small areas of the

target fabric, and ultimately the target support garment, which would normally remain

uncovered. Thus, the utilization of floats increases the opacity of the target fabric and

substantially prevents the production of see-through fabrics. Such opacity is highly

desirable in order to conceal a wearer's body parts from view. Additionally, such

floats also act to increase the heat-moldability or heat-setting of the fabric to the contours and dimensions of at least a portion of a wearer's body structure as well as to

provide increased opacity to the target fabric. This float adds strength to the fabric

while also retaining the ability to be modified upon exposure to heat and thus to retain

its molded orientation upon heat-setting. In such a manner, the different, individual

floats within the target fabric orient themselves to different positions (lengths,

stretches, directions, etc.) when fitted to a wearer's body. When subsequently exposed

to sufficient heat for heat-molding, the floats remain in substantially the same position

as the wearer requires for maximum comfort. As noted above, the other fibers,

including the spandex components, will also become heat-set to a certain degree as well.

The important aspects of this invention lie first in the specific method utilized

to incorporate the spandex fibers within the circular knit construction and second in

the utilization of at least one float (of a fiber which is not spandex) within each

repeating knit pattern of the target fabric. As noted above, the specific method entails

keeping the tension on the spandex substantially constant during the delivery of the spandex thread (or yarn) to the needle bed of the circular knit machine. The thread (or

yarn) is then elongated to at least 100%> of its stretch capability while it is fed into the

needle bed and threaded through a carrier fabric. The thread (or yarn) is then pulled

into the loop construction of the fabric while still elongated. After knitting the fiber

can then relax into original shape.

Such a procedure has not been practiced in order to produce relatively high

spandex-content circular knit fabrics. The pre-elongation of the thread (or yarn)

permits incorporation of the spandex fibers in high amounts within the target circular

knit fabric without compromising the desired comfort offered to the wearer of the

ultimate support garment. It is believed, without intending to be limited to such any scientific theory, that the prevention of the spandex thread (or yarn) from retaining its

desired shape and length prior to knitting basically allows for the entire knitted fabric

to relax simultaneously from the same consistent tension during knitting. As such,

each relaxed thread or yarn retains its original, inherent shape, length, etc., to the same

degree as the other threads or yarns of the knitted fabric. In the past, the difficulties in incorporating spandex within circular knits stem from the differences in the shapes of the fibers during knitting. A large number of threads having different configurations

from the remaining fibers of the target knit structure affects the shape of the produced

fabric, limits the effectiveness of the produced fabric, and compromises the integrity

of the produced fabric. Thus, non-elongated spandex fibers, for example, would strain

the knitting machine in an attempt to continue the desired pattern, thereby producing a

fabric which had discrete areas of "power" which reduced the aesthetics of the

produced fabric by "warping" the remaining fibers into random directions (such as

puckering). Also, such puckering of fabric could facilitate unraveling of knitted fibers as well as provide difficulties in assessing the proper placement of fabrics within

garments. Thus, the inventive method eliminates such problems by first elongating

the spandex threads (or yarns) and subsequently knitting them into the desired circular

knit structure. The fibers then relax into the same pattern as the other fibers within the

target fabric, which, in turn, provides the basis for the production of powerful, heat-

moldable, and comfortable circular knit high spandex-content support garments.

As one of ordinary skill in this art would appreciate, the continuous

performance of such a specific knitting method is extremely difficult. The ability to

provide knitting needles which can withstand and differentiate the differences in

pressure between spandex fibers and others (such as polyesters, for example) while

also elongating the spandex fibers to relatively large degrees, all while permitting a

reproducible process for an appreciable amount of time is not a simple task. The

inherent difficulties have most likely swayed artisans away from such a specific method in the past. However, if the proper stretching and knitting is performed, the results are the inventive fabrics which are very powerful and comfortable at the same time.

As noted above, this inventive fabric may be incorporated into any type of support garment since the high amounts of spandex provide the proper amount of

stress and strain for the target fabric. The fabrics may be knit in different fashions in order to provide more power to discrete areas of the fabric depending on the type of

support garment within which such fabric will be incorporated. As merely non-

limiting examples, brassieres, including sports bras, braces, and athletic supporters are

contemplated as support garments for the inventive fabrics.

Brief Description of the Drawings

FIG. 1 is a top view of a portion of an inventive moldable circular knit fabric.

FIG. 2 is a rear view of the same inventive fabric of FIG. 1.

While the invention will be described in connection with preferred embodiments and procedures, it is to be understood that the invention is in no way

intended to be limited by such description. On the contrary, it is intended to cover all

alternatives, modifications and equivalents as may be included within the true spirit

and scope of the invention as defined by the claims appended hereto.

Detailed Description of the Drawings

Turning now to the drawings wherein like reference numerals designate like

components in the various views, in FIG. 1 there is shown a prefeπed heat-moldable inventive fabric 20 is shown which comprises three separate yarns 22, 24, 26 per

stitch. The particularly preferred yams are comprised of spandex 22, possessing a

preferred denier of about 140, 2-ply 68 count polyester filament 24, possessing a

prefeπed denier of about 70, and a single 68 count polyester filament float yam 26,

also having a denier of about 70. The spandex yams 22 are preferably incorporated as

the top yam within each repeating stitch pattern in order to provide greater power

internally within each stitch. The float 26 is incorporated in order to provide the moldable characteristics as discussed at greater length above.

FIG. 2 represents the rear view of FIG. 1 and illustrates, again, the prefeπed

stitch pattern within the fabric 20 wherein the spandex yams 22 are present as the top

yams within each repeated stitch in order to supply the desired amount of power for

both support and comfort to the wearer. The spandex yams 20 was measured to

comprise roughly 24% of the total weight of the fabric 10.

As these are merely prefeπed embodiments, the possible range of amounts of

spandex yarns within the inventive fabrics may be as low as 24% of the total fiber

content of the entire fabric structure. An upper limit of roughly 75% would present a

limit as to constrictive power for utility within a proper, comfortable support garment.

More preferably would be a spandex amount of between 24 and 50%.

There are, of course, many alternative embodiments and modifications of the

present invention which are intended to be included within the spirit and scope of the following claims.

Claims

Claims What we claim is:

1. An opaque heat-moldable circular knit fabric comprising at least two different

types of fibers, one being spandex and the other at least one non-spandex-containing

fiber, wherein the total amount present within said fabric of said spandex fiber is at

least 24%) of the total fiber content of the entire fabric, and wherein at least one non-

spandex-containing float per repeated knit pattern is present within the knit fabric.

2. The fabric of Claim 1 wherein said at least one non-spandex-containing fiber

is selected from the group consisting of polyamide, polyester, cotton, wool, ramie,

acetate, polyurethane, and any blends thereof.

3. The fabric of Claim 2 wherein said at least one non-spandex-containing fiber

acetate, polyurethane, and any blends thereof.

4. A support garment comprising the heat-moldable circular knit fabric of Claim

1.

5. A support garment comprising the heat-moldable circular knit fabric of Claim

2.

6. A support garment comprising the heat-moldable circular knit fabric of Claim

3.

7. The a method of forming an opaque heat-moldable, circular knit fabric

comprising spandex in an amount of at least 24%> by weight of the fabric, said method

comprising the steps of:

(a) providing at least one thread of spandex fiber and at least one non-

spandex-containing thread; (b) delivering said threads to a needle bed under constant tension;

(c) feeding said threads into a needle bed while simultaneously elongating said spandex thread to 100% of its total stretch capability;

(d) introducing said elongated spandex thread and said non-spandex-

containing thread within a carrier fabric comprising at least one fiber selected from the

group consisting of polyamide, polyester, cotton, wool, ramie, acetate, polyurethane,

and any blends thereof;

(e) pulling said threads into the loop construction of the resultant circular

knit fabric; and

(f) knitting at least one non-spandex-containing float per repeated knit

pattern into the fabric structure; and, as optional steps,

(g) incorporating the circular knit fabric into a garment; and

(h) heat-setting the garment of step "g" to a pre-selected orientation.

8. A heat-moldable circular knit fabric formed through the method of Claim 7.

9. A support garment comprising the fabric of Claim 8.

10. The method of Claim 7 wherein step "g" is present.

11. The method of Claim 10 wherein steps "h" and "i" are also present.

12. The fabric of Claim 1 wherein said spandex fiber comprises from about 24 to

about 75%> by weight of the fabric.

13. The fabric of Claim 12 wherein said spandex fiber comprises from about 24%>

to about 50%) by weight of the fabric.

14. The fabric of Claim 13 wherein said spandex fiber comprises about 24% of the

weight of the fabric.

15. The method of Claim 7 wherein said spandex fiber comprises from about 24

to about 75%) of the weight of the fabric.

16. The method of Claim 15 wherein said spandex fiber comprises from about

24%o to about 50% of the weight of the fabric.

17. The method of Claim 16 wherein said spandex fiber comprises about 24% of

the weight of the fabric.