US3382552A - Process to compact fabric - Google Patents

Description

y 1968 T. A. DAVIS ET AL 3,382,552

PROCESS TO COMPACT FABRIC Filed March 24, 1965 2 Sheets-Sheet 1 INVENTORS A. DAVIS D. GUTIERREZ ATTORNEY May 14, 1968 T. A. DAVIS ET AL.

PROCESS T0 COMPACT FABRIC 2 Sheets-Sheet 2 Filed March 24, 1965 FIG. "3

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THOMAS A. DAVIS CARLO S D. GUTIERREZ United States Patent 3,382,552 PRGCESS T0 CQMPACT FABRIC Thomas A. Davis, Columbia, and Carlos D. Gutierrez,

Spartanhurg, S.C., assignors to Deering Millikan Research Corporation, Spartanburg, S.(,., a corporation of Delaware Filed Mar. 24, 1965, Ser. No. 442,291 8 Claims. (Cl. 26-13.6)

This invention relates to apparatus for the preparation of stretch fabric and more specifically to apparatus suitable for the preparation of stretch fabric having elastic characteristics in the direction of the fill yarns.

In general, elastic effects are produced in a fabric either by preparing fabrics from elastic yarns or by compacting preformed fabrics prepared from yarns having no prior stretch characteristics. Stretch yarns are commonly prepared by employing an elastomeric component as a core about which non-elastic fibers are spun. A second means for producing stretch yarns is by compacting or crimping the yarns or the staple fibers employed in the preparation of the yarns. Methods which are commonly employed for the preparation of such non-core spun stretch yarns are gear crimping, knit-unknit methods, edge-crimping, belt crimping, blowing methods and twistset-untwist methods.

While stretch fabrics may be prepared from the stretch yarns produced according to any of the aforementioned processes, great care must be exercised in the preparation of the stretch fabrics to insure that the elastic characteristics of the yarns are not lost in the subsequent knitting or weaving operations. It is therefore often desirable to produce stretch characteristics in preformed fabrics. Stretch fabrics produced in the piece are now being prepared according to US. Patents Nos. 3,077,655, 2,765,513, and 2,765,514. The first of these patented processes involve a combination of factors among which are fabric construction, chemical treatments and mechanical action. In its most general terms, the process set forth in US. Patent No. 3,077,655 involves the preparation of a loosely constructed fabric from high twist wool yarns, immersion of the fabric in a reducing agent followed by agitation of the fabric between vibrating members whereby the fabric is alternately compacted and released thereby permitting the high twist yarns to contract and create a stretch fabric having elastic characteristics in both the warp and fill direction. Another process for the preparation of stretch fabric is embodied in US. Patents Nos. 2,765,513 and 2,765,514. The process set forth in these two patents involve the compacting of a fabric in the direction of the warp yarns by the passage of the fabric into a machine consisting of two rolls and a blade. The b ade is in close proximity to the upper roll to form a primary feed nip. A fabric entering the apparatus between the blade and a smooth compounded upper roll assumes the speed of that roll. The fabric then passes from this primary nip to a second nip formed by the two rolls themselves. The lower roll possessing a higher coefficient of friction than the top roll and traveling at a slower speed than the top roll takes control of the fabric from the top roll because the fabric is being fed into the apparatus at a faster rate by the first nip and is being taken away at a slower rate. At the second nip the column of fabric supported between the nip is under a state of longitudinal compression and a fabric having elastic characteristics in the direction of the Warp yarns is created.

Stretched fabric developed in the piece according to the methods heretofore known have resulted in a product having a certain degree of stretch. It is found that, in general, these fabrics are limited to less than 25% extensibility in either the warp direction or the fill direction.

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The reason for this low degree of stretch is due to the fact that compacting in the direction of the warp yarns of a preformed fabric is limited by the high twist construction of the warp yarns in most fabrics and by the warp yarn tensions during weaving operations, both these high twist and high tension characteristics tending to limit the degree to which a fabric may be compacted in the direction of the warp yarns. When a fabric is compacted by relying upon the internal contractions inherent in high twist years by subjecting a preformed fabric prepared from high twist yarns to agitation, the yarns themselves will provide a limiting factor to the degree of compaction which may be obtained. A second limiting factor to the degree of stretch obtainable from internal yarn contractions is that the agitated fabric held in an untensioned state will buckle badly if extensive contraction is induced within the yarns.

it is therefore an object of this invention to provide an apparatus which will produce fabric that has stretch characteristics in the fill yarn direction.

It is another object of this invention to provide an apparatus for the preparation of a fabric having stretch characteristics in the direction of the fill yarns by application of external forces in the direction of the fill yarns.

It is a further object of this invention to provide a continuous process for the preparation of a fabric having stretch characteristics in the direction of the fill yarns by application of external forces in the direction of the fill yarns.

It is still another object of this invention to provide a fabric having stretch characteristics in the direction of the fill yarns.

In accordance with this invention, it has now been discovered that it is possible to produce a fabric having stretch characteristics along the direction of the fill yarns by means of an apparatus comprising a plurality of stiff, rotatable, longitudinally curved shafts in parallel alignment, each of said shafts being in contact with at least one other of said shafts and being in substantially the same plane. The curved shaft members may be commercially available compactor rolls. The compactor roll with which this invention is concerned comprises a curved shaft clamped at its ends, a series of metal roll sections rotatably mounted on the shaft in end-to-end relation by means of bearings and a rubber-like sheath closely surrounding the roll sections and forming the working surface of the roll. Rolls of this type are described in US. Patents Nos. 2,898,662 and 2,960,749 and are produced by the Mount Hope Machinery Company of Taunton, Mass.

If a sheet material is fed to the roll at its convex side and leaves the roll at its concave side, the sheet will tend to contract widthwise as it travels partly around the roll. As each of the plurality of roll members are in intimate contact with each other, the sheet material will retain that degree of compaction produced by one roll member when being passed to a succeeding roll member for further compaction. While any number of rolls in excess of two may be employed in the apparatus of this invention, the actual number is determined by the amount of total compacting desired and by the degree of compacting effected by each 'adivi-dual roll member. It is preferred that the rolls have an outside diameter of from about 1 inch to about 6.5 inches and have a radius of curvature or how sufficient to produce a compaction of from about 1% to about 10%. It is also preferred that the bow of each successive roll increase, in order to prevent wrinkling of the fabric during compacting operations, that is to say the roll at the point of fabric ingress should have the least amount of bow in the roll series while the roll at the point of fabric egress should have the greatest amount of how in the roll series. If the compactor roll members are to be subjected to high temperatures it is also desirable that the roll cover or sheath be made of a heat resistant material such as silicone rubber or more preferably a fluorocarbon rubber such as, for instance, Viton (fluorocarbon elastomer marketed by E. I. du Pont de Nemours and Co.).

A better understanding of the invention may be had from the drawings in which:

FIGURE 1 is a schematic view of one embodiment of the apparatus of this invention.

FIGURE 2 is an expanded view of one portion of the apparatus of FIGURE 1.

FIGURE 3 is an enlarged photograph of a polyester/ worsted fabric prior to compacting by means of external forces.

FIGURE 4 is an enlarged photograph of a polyester/ worsted fabric subsequent to compacting by means of external forces.

FIGURE 5 is an enlarged (twenty power) cross-sectional photograph of the fabric of FIGURE 3.

FIGURE 6 is an enlarged (twenty power) cross-sectional photograph of the fabric of FIGURE 4.

FIGURE 7 is an enlarged (fifty power) cross-sectional photograph of a cotton fabric prior to compacting.

FIGURE 8 is an enlarged (fifty power) cross-sectional photograph of a cotton fabric subsequent to compacting by means of external forces.

FIGURE 9 is an enlarged (fifty power) cross-sectional photograph of a polyester fabric made from filament yarns prior to compacting.

FIGURE 10 is an enlarged (fifty power) cross-sectional photograph of a polyester fabric made from filament yarns subsequent to compacting by means of external forces.

FIGURE 11 is an enlarged (fifty power) cross-sectional photograph of a polyester/cotton fabric prior to compacting.

FIGURE 12 is an enlarged (fifty power) cross-sectional photograph of a polyester/cotton fabric subsequent to compacting by means of external forces.

Turning to FIGURE 1 of the drawings, a roll of fabric 1 which may be a fabric such as, for instance, a polyester fiber fabric is passed over suitable guide roll member 2 into steamer member 3. The steamed fabric is then passed over the first of a plurality of compactor roll members 4, the fabric being subjected to the compacting operation by passage over compactor roll members 4. It is also subjected to a simultaneous setting operation, the setting operation being accomplished by means of a bank of infrared lamp members 5 superimposed above the compactor roll members 4. It is preferred that the fabric be maintained in a moistened condition so as to increase the propensity of the fabric to compact, the moistening of the fabric being accomplished by means of the water vapor generated by heated water bath 6 positioned directly below compactor roll members 4. Maximum compacting is preferably obtained by immersion of the fabric into a water bath 7 by passage under an immersed compactor roll member 8 at a point substantially midway through the compactor roll series. The water-wetted fabric is then subjected to the same type of operation as had been carried out prior to immersion in the water bath, that is to say the fabric is passed over additional compactor members 4 simultaneous to being subjected to the action of infrared lamp members 5 and moisture from heated water bath members 6, The now compacted fabric is passed over a singular noncontacting compactor roll member 9 which is preferably of greater diameter than the preceding series of compactor roll members. The enlarged compactor roll member 9 serves to remove wrinkles from the compacted fabric prior to subjecting the compacted fabric to the action of flat roll members. The wrinkle free compacted fabric is then passed beneath a lower squeeze roll 10 and then into nip formed by compacting an upper squeeze roll 11 with lower squeeze roll member If). The fabric is then wound onto a suitable takeup roll 12 which is driven by means of drive roll 13. Drive roll 13 as well 4 as squeeze roll member 11 is powered by a suitable driving means such as, for instance, an electric motor and pulley arrangement 14.

A better understanding of the compaction which takes place in the fabric by passage over compactor roll members 4 may be had from FIGURE 2 of the drawings! wherein the reduction in width of fabric 21 is clearly noted in the passage of the fabric over compactor roll members 2.4. The end and side portions of water bath 27 have been cut away in order to clearly illustrate the passage of the fabric from the nip formed by two contacting compactor roll members 24 around and underneath immersion compactor roll member 28 and then again into the nip formed by two contacting compactor roll members 24. For ease of illustration, the compactor roll members 24 immediately above immersion compactor roll member 28 and immediately preceding immersion compactor roll member 23 have been cut away. As may be noted from an overall view of FIGURE 2, fabric 21 is being compacted from about 3% to about 5% in passing over each of compactor roll members 24. Roll member 29, it should be noted, is positioned so as to expand compacted fabric 21, thereby removing any wrinkles which may have been produced in the compacting operation.

Fabrics which are suitable for compacting according to the process described herein are any fabrics which are prepared with a reeded out construction, that is to say any fabrics which have a construction such as will admit compacting along the direction of the filling yarns. Specific textile materials which may be employed in the construction of such fabrics are any textile material which will lend themselves to a setting operation subsequent to or simultaneously with a compacting operation. As previously mentioned, the setting operation may be any of the setting operations well known to the art such as, for instance, the use of a reducing agent setting operation for yarns containing keratinous fibers, the use of cross-linking agents in the setting of cellulosic type yarn and the use of heat setting mediums for thermoplastic yarn, the selection of the particular setting medium being employed depending, of course, upon the type of fiber present to the greatest degree in the yarn or the percentage of fibers of a particular nature coupled with the ability of such fibers to retain a permanent set.

The yarns employed in the fabrics suitable for compacting according to the process described herein are both high and low twist yarns. It should be understood, however, that the process of this invention lends itself to the preparation of stretch fabrics from fabrics containing yarns of lower twist multiple than may be employed in processes which require internally generated compacting forces. When stretch fabrics are prepared by means of internally generated compacting forces such as in the process described in US. Patent No. 3,077,655, worsted wool yarns having a twist multiple in excess of about 2.6 must be employed. When stretch fabrics are prepared according to the process set forth herein, however, worsted wool yarns having a twist multiple of less than about 2.6 may be satisfactorily employed. correspondingly, low twist woolen system yarns may also be satisfactorily employed, that is to say woolen system yarns having a twist multiple of less than about 8 and preferably from about 5 to about 8 may be employed. Twist multiple is a term common to the textile industry and may be defined as turns per inch divided by the square root of the yarn count.

The following specific examples for the preparation of the stretch fabrics of this invention are given for the purposes of illustration and should not be considered as limiting the spirit or scope of this invention:

Example I An all wool fabric having 35 ends per inch and 29 picks per inch and having a warp and filling yarn count of 4.6 woolen run is passed into a reducing agent bath comprising an aqueous solution of sodium borohydride at a concentration of about 2% by weight. The reducing agent treated fabric is then passed through a set of squeeze rolls and then into a fourteen roll compactor roll appa ratus, the apparatus being of a type as previously described. The compacted fabric is then wound upon a decating roll and subjected to 2O minute aging operation at a temperature of about 80 F. The fabric is then dried in a Fleissner drier (relaxed drum drier) at 200 F. After drying the fabric is semi-decated with a cycle of steam breakthrough plus a ten second steaming followed by two minutes vacuum pumping. The wool fabric, set in its compacted configuration, is found to have a substantial degree of stretch along the direction of the fill yarns. The stretch fabric is found to have 46 ends per inch and 23 picks per inch.

Example II A 55% polyester/45% worsted wool fabric having 49 ends per inch and 43 picks per inch and a worsted warp yarn count of /1 and a worsted filling yarn count of 20/1 is fed into a sixteen roll compactor roll apparatus, the apparatus being of the type previously described. The apparatus is allowed to force the fabric into about 40% of its original width. Simultaneous to the compacting operation, the polyester/worsted wool fabric is subjected to a heat treatment at temperatures approaching a suitable thermal transition point of the polyester fibers. The compacted fabric upon emerging from the compactor roll apparatus is found to have 40% stretch when subjected to a load of two pounds per inch of fabric sample width and an unrecovered stretch of 3.9%, the unrecovered stretch being reported on the basis of percentage of the orginal length after being held five minutes at extension and allowed to recover five minutes after unloading.

Example III A 100% cotton fabric having 76 ends per inch and 70 picks per inch is fed into a nineteen roll compactor roll apparatus substantially as previously described. The fabric upon emerging from the compactor roll apparatus is found to have been compacted about of its original width. The cotton fabric is then set in its compacted configuration by treatment with a dihydroxy dimethylol ethylene urea cross-linking agent. The final product is found to have 35 stretch under a load of two pounds per inch of sample width and to have a 5.6% unrecovered stretch, the unrecovered stretch being reported as percent of original length after being held five minutes at 30% extension and allowed to recover five minutes after unloading.

Example IV A polyester continuous filament yarn having 144 ends per inch and 100 picks per inch and having a denier yarn count in both the warp and filling directions is subjected to the same processing operation as set forth in Example II. The finished product is found to have 227 ends per inch and 99 picks per inch and to have a 34% stretch at a load of two pounds per inch of sample width with 8.0% unrecovered stretch, the unrecovered stretch being reported as percent of original length after five minutes at 30% extension and allowed to recover five minutes after unloading.

Example V A 65% polyester/35% cotton fabric having 92 ends per inch and 76 picks per inch and a yarn count (cotton system) of /1 in both the warp and filling direction is processed according to the procedure set forth in Example II. The finished product is found to have 121 ends per inch, 74 picks per inch and to have a stretch of 35% under a load of two pounds per inch of sample width with an unrecovered stretch of 5.4%. The unrecovered stretch is reported as percent of original length after being held five minutes at 30% extension and allowed to recover five minutes after unloading.

Example VI A fabric having a fiber content of 65% polyester and 35% cotton and a construction of 87 ends per inch and 67 picks per inch is processed according to the procedure set forth in Example II, the compaction produced by the compactor roll apparatus being about a 42% reduction of the original width of the fabric. The fabric having a yarn count in the cotton system of 40/ l in both the warp and filling directions is a fabric having 113 ends per inch, 62 picks per inch and a stretch of 42% under a load of two pounds per inch of sample width, the unrecovered stretch being 5.8%. The unrecovered stretch is reported as percent of original length after being held five minutes at 30% extension and allowed to recover five minutes after unloading.

Example VII A fabric having a fiber content of 65% polyester/35% rayon and having a fabric construction of 64 ends per inch and 60 picks per inch with a yarn count on the cotton system of 20/1 in both the warp and filling direction is processed according to the procedure set forth in Example II. The final product is found to be a fabric having 90 ends per inch, 56 picks per inch and a stretch of 30% a load at two pounds per inch of sample width. The unrecovered stretch is found to be 5.5%, unrecovered stretch being reported as percent of original length after being held five minutes at 30% extension and allowed to recover five minutes after unloading.

The determination of elasticity in the finished product as reported in the foregoing examples was determined by cutting test specimens 2 inches by 24 inches with the longer length being parallel to the stretch direction. The upper end of the test specimen is then secured to a clamp member while the lower end of the test specimen is subjected to a load of four pounds (two pounds per inch). The specimen is then exercised by cycling three times between a zero load and a two pound load at approximately five seconds per cycle. The increase in length is then recorded within 30 seconds after the completion of the fourth loading cycle. The increase in length over the initial length multiplied by is then recorded as the percent stretch.

The extent to which a fabric has been compacted and correspondingly given stretch characteristics is readily discernible from a review of FIGURES 3 through 12 which are enlarged photographs of fabrics and fabric cross sections prior to compacting and subsequent to compacting operations. The cross sections in each of FIGURES 3 through 12 are cross sections made by cutting through the warp yarns. The increase in both frequency and amplitude of the filling yarns may be seen in each set of fabric cross sections subsequent to compacting. It is important to note that the finished stretch fabric prepared according to the process of this invention may be a fabric having low twist yarns, the low twist yarns, of course, having greater bulk and resulting in a fabric having a superior hand than fabrics prepared from the high twist yarns which are necessary in the preparation of fabrics compacted by internal forces. While the stretch fabrics of this invention may be prepared from either high or low twist yarns, it is an important feature of the present invention that stretch fabrics may be prepared from yarns having insulficient twist to produce internal compacting forces.

Having thus described the invention, what is claimed is:

1. A continuous process to impart stretch characteristics to a woven fabric having an open weave comprising: supplying said open weave fabric to a compacting surface, compacting said fabric in the fill direction on said comr pacting surface, maintaining said fabric in compacted condition while supplying said fabric to a further compacting surface, compacting said fabric further in the fill direction, repeating the compacting of said fabric in the fill direction on further compacting surfaces While maintaining the fabric in its compacted conditions at all times and setting the fabric in its compacted configuration.

2.. The process of claim 1 wherein said fabric is compacted from about 1% to 10% in width on each compacting surface.

3. The process of claim 2 wherein said fabric is compacted in the fill direction greater than 25%.

4-. The process of claim 1 wherein the fabric is set in the compacted configuration simultaneously to compaction on said compaction surfaces.

5. A continuous process to impart stretch characteristics to a woven fabric having an open weave comprising: supplying said open Weave fabric to the long side of an arcuate member, moving said fabric from the long side of said arcuate member to the short side of said arcuate member to compact the width of the fabric, maintaining 6. The process of claim S Wherein said fabric is compacted from about 1% to 10% in width on each arcuate member.

7. The process of claim 6 wherein said fabric is compacted in the fill direction greater than 25%.

8. The process of claim 5 wherein the fabric is set in the compacted configuration simultaneously to compaction on said arcuate member.

References Cited UNITED STATES PATENTS 1,988,376 1/1935 Dcsmet 26-186 -2,849,781 9/1958 Rosen 26-186 3,100,925 8/1963 Messinger 26-186 1,660,224 2/1928 Farrell 26-63 1,814,652 7/1931 Weiss 26-63 2,021,975 11/1935 Wrigley et al. 26-186 2,535,734 12/1950 Grettve. 2,574,200 11/1951 Teague 26-186 X 2,626,422 1/1953 Lammertse 26-63 X 2,905,999 9/1959 Parker et a1 26-54 X 2,979,131 4/1961 Bontov.

FOREIGN PATENTS 43,197 5/1938 Netherlands.

ROBERT R. MACKEY, Primary Examiner.

Claims (1)

1. A CONTINUOUS PROCESS TO IMPART STRETCH CHARACTERISTICS TO A WOVEN FABRIC HAVING AN OPEN WEAVE COMPRISING: SUPPLYING SAID OPEN WEAVE FABRIC TO A COMPACTING SURFACE, COMPACTING SAID FABRIC IN THE FILL DIRECTION ON SAID COMPACTING SURFACE, MAINTAINING SAID FABRIC IN COMPACTED CONDITION WHILE SUPPLYING SAID FABRIC TO A FURTHER COMPACTING SURFACE, COMPACTING SAID FABRIC FURTHER IN THE

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