US2791021A

US2791021A - Process of making an improved resilient fabric

Info

Publication number: US2791021A
Application number: US344790A
Authority: US
Inventors: Carroll R Anderson
Original assignee: Munsingwear Inc
Current assignee: Munsingwear Inc
Priority date: 1953-03-26
Filing date: 1953-03-26
Publication date: 1957-05-07
Anticipated expiration: 1974-05-07

Description

May 7, 1957 c. R. ANDERSON PROCESS OF MAKING AN IMPROVED RESILIENT FABRIC Filed March 26, 1953 2 Sheets-Sheet l INVENTOR. OIRROL 1. R. 4/voERs0/v ATTORNEYJ" May 1957 c. R. ANDERSON 2,791,021

PROCESS OF MAKING AN IMPROVED RESILIENT FABRIC Filed March 26, 1953 2 Sheets-Sheet 2 HEAT/N6 Q) 2 g 3 I 3 1,: k

I I INVENTOR.

CARROLL R. ANDERSON ATTORNEYS United States Patent PROCESS OF MAKING AN IMPROVED RESILIENT FABRIC Carroll R. Anderson, Minnetonka Beach, Minn., assignor to Munsingwear, Inc., Minneapolis, MIIIIL, a corporation of Delaware Application March 26, 1953, Serial No. 344,790

16 Claims. (Cl. 26-68) This invention relates to a process of making an improved resilient fabric and more particularly to a process of making an improved resilient fabric from linear polyamide yarns for use in garment structures composed completely or partially of such fabrics. This application is a continuation-in-part of my copending application Serial No. 190,990, filed October 19, 1950, now Patent No. 2,636,368 issued April 28, 1953.

In many garments it is desirable to construct the whole garment or portions of the garment from fabrics having a resilient characteristic in one or more directions. Prior to the invention in my application Serial No. 190,990 aforesaid and this invention, many commercial garments have been constructed of fabrics knitted from rubber-elastic yarns. Such rubber-elastic yarns are knitted under tension and after knitting the yarn tends to contract and the fabric accordingly assumes a smaller size in its relaxed condition than when under tension across the fabric. Such fabrics made of rubber-elastic yarns knitted under tension are well known and have a great usefulness but unfortunately are subject to relatively short life and frequently do not perform their function throughout the normal life of the garment. Knitted resilient or stretchable" fabrics made from rubber-elastic yarn have been the best available for use in such garments as girdles, in the waist bands of pajamas, shorts, wristlets and the like prior to the invention of my aforesaid application.

The principal disadvantage of fabrics knitted from rubber-elastic yarns is that the elastomer which is used as the resilient base of the yarn, whether of natural or synthetic type, is subject to short life and accordingly a garment composed of such materials may lose its stretch in a matter of months of wear or even during shorter times. Furthermore, the deterioration occurs on the shelf and in order to obtain the most service from such garments they must be merchandised and used within a reasonable time after being made. Such stretchable fabrics made of rubber-elastic yarns, regardless of whether the rubber is natural or synthetic, are particularly subject to deterioration due to laundering, for water and detergents markedly reduce the life of such elastic members. Since laundering is essential in the use of most fabrics that are used for body garments, this reduction in life of the garment due to laundering has had to be accepted as one of the inherent limitations of such fabrics. The heat encountered in drying the laundered garment and in ironing cause further deterioration of the elastic yarns.

It is a principal object of this invention, therefore, to provide an improved process of making a resilient fabric having long service life.

It is another object of this invention to provide a process of making an improved resilient fabric knitted from yarns composed of polyamide condensation products, said yarns being selected from a specified range of 2,191,024 Patented May 7, 1 957 'ice sizes and having a ratio of the number of filaments to the denier size of the yarn in a specified ratio range.

It is another object of this invention to provide a process for treating elastic fabrics knitted from yarns composed of polyamide condensation products for the purpose of improving and enhancing their resiliency, and to provide improved knitted fabrics so treated.

Other objects will become apparent as the description proceeds.

Broadly stated, the invention comprises a process of making an improvedresilient fabric which includes the steps of treating a fabric knitted from a yarn made up of a plurality of filaments composed of a linear condensation polymer by subjecting this knitted fabric to eittreme tension in the direction of knitting and then while so tensioned, heating said stretched fabric.

The invention is illustrated with reference to the drawings in which corresponding numerals refer to the same parts and in which:

Figure 1 is an enlarged fragment of a representative fabric made in accordance with the instant invention;

Figure 2 is a side elevational view of a diagrammatic representation of one form of apparatus for carrying out this invention; t.

Figure 3 is a fragmentary perspective view of one form of tensioning means.

In carrying out the invention there are utilized yarns composed of linear condensation polymers made in accordance with one or more of the following patents: 2,071,250 through 2,071,253; 2,130,523; 2,130,948; 2 14-9,286 and 2,149,273. Fiber forming polyamide yarns, such as nylon, have especial usefulness in this invention. Throughout this specification and in the claims, the term linear condensation polymer yarns will be understood to include yarns made in accordance with the aforesaid patents and more especially fiber forming polyamide yarns, such as nylonyarns. Such linearcondensation polymer yarns are the yarns of commerce and are pro stretched by the yarn manufacturer, in which prestretched condition they are sold in commerce. Thus, commercial nylon yarns of appropriate denier size and filament count, as hereinafter described and ready for knitting may be used.

In carrying out the invention the fabric isknitted utilizing such linear condensation polymer yarn having a denier size in the range of to 300,, said yarns being composed always of a plurality of filaments. The number of filaments in the yarn must be such that the ratio of the number of filaments divided by the denier size number is in the range from 0.02 to 0.15. Best results are obtained when the ratio of the number of filaments in such yarn to the denier size number is in the preferred range of 0.03 to 0.10. The knitted fabric is preferably a 1 x 1 rib knit fabric, but other knitted fabrics such as the Swiss knit fabric may also be used, although the 1 X 1 rib knitfabric is preferred because of its inherent greater stretch resistance transversely of the direction of knitting.

Thus, in accordance with the invention the fabric may be knitted from yarns composed of the stated linear condensation products in the size range from 100 to 300. For example, yarns having a denier size of'100 and having from 2 to 15 filaments are satisfactory where it is desired to have a fabric which stretches easily with low pull, the stretch, of course, knitting. Whereit is desired to have a fabric which, though elastic (in the direction transverse to the direction of knitting) yet requires more force (pull) to cause the stretching, the yarn size should be increasedto, for example, 200 denier size and having a number of filaments ranging from about 4 to about 30. Likewise, wherestill greater strength is needed, while still preserving the being transverse to the direction of is subjected to a tensioning and heating treatment.

fabric is tensioned by stretching in the direction of knitcharacteristic of elasticity transverse to the knitting direction, yarns of size 250 denier and having a number of filaments from about 5 to about 38-40 are satisfactory. For maximum transverse elastic strength, yarns of 300 denier size are utilized having a number of filaments ranging from about 5 to about 45. It will be appreciated that the number of filaments in the yarn may be varied somewhat out of the stated ranges and likewise slightly larger or smaller denier sizes than those stated may be utilized. For best results, however, the ratio of the number of filaments to the denier size number should be held in the approximate range of 0.02 to 0.15 and the denier size should be from about 100 to about 300.

In order to set the inherent resiliency of the above fabrics knitted from yarns as specified, the knitted fabric The ting. Ordinarily, knit fabric has relatively little elasticity in this direction. The tension which is applied is extreme, being just short of that which. will rupture the filaments of the yarn. This will, in most cases, be tension sufficient to provide an elongation of the knitted fabric in the range of from about 12% to 20%. Thus, the

fabric knitted from one of the specified yarns is stretched by tension in the direction the fabric is knitted (applied substantially uniformly across the width of the fabric) until the increase in length from relaxed condition of the fabric to stretched condition is about 12% to about 20%. While in this stretched condition the fabric is subjected to heat in the range from about 200 to 425 F. Thereafter the tension may be relaxed and the fabric will remain KISBt'QI treatment, the fabric will remain permanently elongated in the range of from about 7% to 15%.

Becausenylon filaments are relatively impervious to moisture the heat may be applied either dry or moist. The use of superheated steam is therefore a convenient It will be found that after the tensioning (with consequent stretching) and accompanied by the heating means of attaining the desired temperature conditions.

. When moist heatis used, it will, of course, be necessary to subject the treated fabric to a drying step. This may beeither before or after the tension on the fabric is relaxed. Afrange from about 250 to 400 F. provides the preferred temperature conditions for achieving permanent set? of the knitted fabrics of this invention.

The tensioning and heating treatments of this invention are not to be confused with the so-called cold drawing through which polyamide filaments are customarily subjected in the process of their formation, nor to the ironing or boarding treatments to which finished woven or knitted fabrics are customarily subjected. Filaments of linear condensation polymers are customarily subjected to cold drawing in the course of their preparation. This stretching in the solid state causes fundamental physical changes to take place in the filament imparting greater strength and pliability to the fibers. Alternatively, the filaments may be stretched after they are twisted into yarns. It is. contemplated that the commercial yarns which are used in the initial knitting step of this invention will have already been subjected to such a preliminary stretching treatment by the yarn manufacturer. If the filamentsor the yarns have not been thus pro-stretched, this treatment is applied before the knitting operation is undertaken.

Before marketing knitted wear it is customary to scour the fabric in a hot soap solution, rinse the fabric and then iron or board it. This is done to give the fabric a neatly pressed appearance. One means of boarding fabrics composed of yarns of linear condensation polymers is to iron it in the presence of superheated steam at temperatures of about 100 C. to 150 C. This treatment differs from the treatment of the instant invention, however, in that it is carried out under minimum tension usually applied transversely of the knitting direction and in an amount merely sufiicient to hold the fabric smooth while it is being ironed. The treatment of this invention is carried out under extreme maximum tension applied in the direction of knitting.

Referring now to the drawings and particularly to Fig ure 1, there is shown here an enlarged fragment of a representative fabric 1 made in accordance with the instant invention. The direction of knitting is shown by double arrow NS and the direction transverse to the direction of knitting is shown by double arrow S. The fabric readily stretches in the direction of the double arrow S and stretches very little in the direction of double arrow NS. Accordingly, when the fabric of Figure l is used in a garment, it is laid so that the direction S will correspond to the direction in the garment in which resiliency is desired.

In Figure 2 there is shown diagrammatically a side elevational view of one form of apparatus by which the instant invention can be carried out. A length of fabric 1 is fed out of hamper 2 in the direction of knitting over guide roll 3, under adjustable drag bar 4, around adjustable drag bar 5, around bar 4 and over bar 5, under guide roller 6, over guide roller 7, under guide roller 8, over guide roller 9 and between driven horizontal transverse rollers 10 for producing slight (smoothing) tension across the fabric, thence passing between heaters, here illustrated as two pairs of steam boxes 1213 and 14-15 to heavy driven calender pull and tensioning rollers 16 and 17 and thereafter over guide roller 18 to hamper 19. The fabric is maintained under tension between drag bars 4 and 5 and calender rolls 16 and 17 which do the pulling. Restraint to movement of the fabric is adjustably applied by the drag bars 4 and 5 which are shown in more detail in Figure 3. The means for initially restraining the fabric comprises parallel bars 4 and 5 fixedly mounted at their ends to either end of bars 20, forming a frame which in turn is pivotally mounted on tnmnions 21 in a frame of the apparatus not shown. The frame may be pivotally adjusted in the direction of double arrows 22--22 and locked in any adjusted position by clamps (not shown) so as to adjust the amount of tension or drag imposed on the fabric. The fabric is threaded under bar 4, around bar 5, thence around bar 4 and over bar 5. It is readily seen that by rotating the frame 420-20-5 clockwise about its pivot 21 (as viewed in Figures 2. and 3) the tension on the fabric will be decreased and vice versa. Then the desired tension (or frictional drag) is applied to the fabric, the entire frame is fixed in its adjusted position. It will be apparent that suitable tensioning rollers may be used in lieu of drag bars 4 and 5. Likewise, other heating elements, such as gas fired or electrically heated elementsmay be used instead of steam boxes 13 through 15. Where such dry forms of heating are used, the drying zone may be considerably shortened or even eliminated. It will also be apparent that the fabric may readily be fed directly from the knitting machine into the treating apparatus used to carry out this invention.

The fabric forming the waist band or other elastic member of a garment may be knitted either as a tubular knit fabric or a flat knit fabric, the tubular knit being preferred for such applications as underwear, waist bands, wristlets, etc. The fabric is preferably knit in a variety of tubular sizes corresponding to the various garment sizes to which the fabric is applied, thus dispensing with any seams vertically through the fabric when applied, for example, as a waistband. However, such a vertical seam is of no particular disadvantage where, for example, it is desired to make a belt opening.

The invention is further illustrated with reference to the following specific example:

A tubular fabric was knitted from nylon yarn of 260 denier having 17 filaments on a conventional tubular knitting machine. The ratio of the number of filaments divided by the denier size was 0.065. This fabric was then fed into a conventional calender (Tube-tex; Tubular Textile Machinery Company, Woodside, Long Island, New York) at the rate of 3.14 inches per second. The fabric was fed through the calender in the direction of knitting and held taut transversely of the direction of feed. For this there is used the mechanism including an inner tensioning frame which imposed just sufficient tension transversely of the direction of knitting (direction S of Figure 1) so as to hold the fabric flat and avoid wrinkles. This tensioning mechanisrn'is a part of the Tube-tex machine. Simultaneously the fabric was held under extreme tension (in the knitting direction NS, Figure 1), such tension being sufi icient to impart about 18% elongation to the fabric, and while thus tensioned the fabric was subjected to superheated steam having a temperature of about 265 F. to 270 F. and to heat radiated from heaters 1215.- The actual temperature of the fabric at A in Figure 2 of the drawing was 230 F., at B 250 F. and at C 260 F. The heated stretched fabric was then passed through the heavy calender and draw rolls 16 and 17 which produced the extreme tension lengthwise of the fabric, and also ironed the fabric. Thereafter the tension was relaxed and the fabric was dried. As a measure of the elongation produced in the direction of knitting by the extreme tension it may be noted that the fabric before treatment had 39-40 courses per inch in the direction of knitting. The same fabric after treatment had 35-36 courses per inch in the direction of knitting. Thus, it is seen that a permanent elongation of 11.2% was imparted to that fabric by the extreme tension in the direction of knitting and heating. Also, the untreated fabric could be stretched by hand in the direction of knitting about 12 to but the treated fabric could be stretched only about 5%.

It is apparent that many widely different embodiments of this invention may be carried out without departing from the spirit and scope thereof. It is to be understood, therefore, that the invention is limited not to the specific embodiments thereof, but only by the. terms of the appended claims.

What I claim is:

1. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.02 to 0.15, by subjecting said knitted fabric to extreme tension in the direction of knitting sufficient to provide in the range of about 12 to 20 percent elongation and heating said stretched fabric to from 200 to 425 F.

2. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.02 to 0.15, by subjecting said knitted fabric to slight tension transverse of the direction of knitting sufficient to hold the fabric smooth and free of wrinkles and to extreme tension in the direction of knitting sufficient to provide in the range of about 12 to 20 percent elongation and heating said stretched fabric to from 200 to 425 F.

3. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.02 to 0.15, by subjecting said knitted fabric to extreme tension in the direction of knitting suificient to provide the range of about 12 to 20 percent elongation, heating said stretched fabric to from 200 to 425 F., and relaxing the tension on said stretched fabric.

4. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.02 to 0.15, by subjecting said knitted fabric to extreme tension in the direction of knitting sufiicient to provide the range of about 12 to 20 percent elongation, subjecting the stretched fabric to moist heat in the range of about 200 to 425 F., relaxing the tension on said stretched fabric and then drying.

5. The process of claim 4 in which the moist heat is applied by steaming.

6. The process of claim 5 in which the stretched fabric is heated in the range of about 250 to 400 F. by applying superheated steam to the fabric.

7. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.03 to 0.10, by subjecting said knitted fabric to extreme tension in the direction of knitting sufficient to provide in the range of about 12 to 20 percent elongation and heating said stretched fabric to from 200 to 425 F.

8. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.03 to 0.10, by subjecting said knitted fabric to slight tension transverse of the direction of knitting sufiicient to hold the fabric smooth and free of wrinkles and to extreme tension in the direction of knitting sufficient to provide in the range of about 12 to 20 percent elongation and heating said stretched fabric to from 200 to 425 F.

9. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.03 to 0.10, by subjecting said knitted fabric to extreme tension in the direction of knitting sufficient to provide in the range of about 12 to 20 percent elongation, heating said stretched fabric to from 200 to 425 F., and relaxing the tension on said stretched fabric.

10. A process of making an improved resilient fabric which comprises treating a fabric rib-knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.03 to 0.10, by subjecting said knitted fabric to extreme tension in the direction of knitting sufiicient to provide in the range of about 12 to 20 percent elongation, subjecting the stretched fabric to moist heat in the range of about 200 to 425 F., relaxing the tension on said stretched fabric and then drying.

11. The process of claim 10 in which the moist heat is applied by steaming.

12. The process of claim 11 in which the stretched fabric is heated in the range of about 250 to 400 F. by applying superheated steam to the fabric.

13. A process of making an improved resilient rib-knit fabric which comprises treating a tubular fabric knit from a yarn made up of a plurality of filaments composed of a linear condensation polymer, the size of such yarn being in the range of about 100 to 300 denier and the number of filaments in said yarn being so selected that the ratio of the number of filaments divided by the denier size is in the range of 0.02 to 0.15, by subjecting said knitted fabric to extreme tension in the direction of knitting sufficient to provide in the range of about 12 to 20 percent elongation and heating said stretched fabric to from 200 to 425 F.

14. The process of claim 13 further characterized by being continuous.

15. A process of making an improved resilient nylon fabric Which comprises treating a tubular fabric rib-knit from a yarn made up from a multiple filament yarn composed of a fiber-forming polyamide material, the denier number of said yarn being substantially 260 and the number of filaments in the yarn being approximately 17, by subjecting said tubular knitted fabric to extreme tension in the direction of knitting sufficient to provide from about 12 to 20 percent elongation, subjecting said Miami-uneasy; t a

stretched fabric to superheated steam in the range of about 250 to 400 F., relaxing the tension on said stretched fabric and drying, whereby the tubular knitted fabric is permanently elongated in the direction of knitting in the range of from about 7 to 15 percent and its resiliency improved thereby.

16. As a new product, the improved resilient rib-knit fabric produced according to the process of claim 1.

References Cited in the file of this patent UNITED STATES PATENTS 1,790,655 Cohn Feb. 3, 1931 2,060,664 Cohn Nov. 10, 1936 2,187,644 Cohn Jan. 16, 1940 2,192,880 Cohn Mar. 12, 1940 2,365,931 Benger Dec. 26, 1944 2,450,022 Schreiner Sept. 28, 1948 2,591,566 Livingston Apr. 1, 1952 2,597,530 Redman May 20, 1952 2,636,368 Anderson Apr. 28, 1953 2,661,520 Hamilton Dec. 8, 1953 i 1 i i