US3029492A - Method for treating woven fabric - Google Patents

Description

April 17, 1962 R. w. CUTLER METHOD FOR TREATING WOVEN FABRIC 2 SheetsSheet 1 Filed June 18, 1958 N LI ATTORNEY INVENTOR.

Roar-2a W. CuTLca R. w. CUTLER 3,029,492

METHOD FOR TREATING WOVEN FABRIC April 17, 1962 '2 Sheets-Sheet 2 Filed June 18, 1958 INVENTOR. ROGER W. CUTLER ATTORNEY United States Filed Tune 18, 1958, Ser. No. 742,772 7 Claims. (0.26-68) This invention relates to a method and apparatus for treating woven textile materials, and more particularly to an improved method and apparatus for treating narrow woven fabrics by impregnating and attenuating the fabrics in a liquid bath and then drying same.

It is well known to those skilled in the art relating to the treatment oftextile yarns and fabrics that the characteristics of such textile material may be improved by impregnation in liquid mediums of various types, usually in the form of emulsions. Formerly, in such impregnating processes, the textile material is stretched during its passage through the fluid medium or while the yarn still car- I'lBS an excms of the liquid medium. Whil such processes have proved very advantageous in treating many different types of textile products, it is desired that the strength and wearing properties of textile material be improved even more than has heretofore been possible. It is particularly desirable that tape or belting, especially where it is constructed of filament or spun yarn, have its wearing qualities and strength improved. It is especially important that the stretch at break of the yarn be controlled within desirable limits.

Accordingly, it is an important object of this invention to improve the wearing qualities especially of narrow fabrics by an improved process and apparatus for impregnating, attenuating, and drying of the fabric.

Another object of this invention is the provision of a method of impregnating narrow woven fabrics in which the fabric is passed through a fluid medium and subjected to the rubbing action of submerged rolls, and in which the yarn is pushed forwardly by the rolls but which is at no time stretched by being subjected to tension.

An important object of this invention is the provision of a method of treating narrow woven fabrics in which the stretch at break of the fabric is controlled within desirable limits.

Another object of this invention is to provide an apparatus for treating narrow woven fabric in which oscillating rolls are provided for twisting and untwisting the waip yarns passing in contact with the rolls While the rolls are immersed in a fluid medium and for drying the fabric relatively rapidly while subjecting the fabric to sufiic-ient tension to maintain the attenuation already imparted to the fabric.

A further important object of this invention is the provision of a method of impregnating, attenuating and drying narrow woven fabrics in which the fabric is impregnated by the application of a iluid medium thereto while subjected to the application of pressure by transversely oscillating rolls and the fabric pushed forwardly without tension and in which the fabric is dried relatively rapidly while being subjected to tension just suiiicient to maintain the attenuation imparted to the fabric during the steps prior to drying.

Another object of this invention is the provision of a method of impregnating narrow woven fabrics such as discussed above in which the fluid medium is an emulsion including polyvinyl acetate in such proportion as to leave from about 3% to 6% solids in the fabric.

Some of the methods provided to carry out the invention will be hereinafter described.

The invention will be more readily understood from a reading of the following description and by reference to.

the accompanying drawings forming a part thereof whereatent 3,029,492 Patented Apr. 17, 1962 FIGURE 2 is a perspective view at a reduced scale looking from the right hand rear side of FIGURE 1, and

FIGURE 3 is an enlarged transverse sectional view taken on the line 3--3 in FIGURE 1.

Referring more particularly to the drawings, woven material or tape T is shown being fed from a source of supply and under a partially submerged horizontal transversely disposed roll A. The fabric T passes between the bite of the first of a pair of axially oscillating rolls B on the forward side of roll A and thence between the bite of the second of the submerged axially oscillating rolls B on the far side of roll A. From thence the tape T passes under the first of a second pair of rolls C which are shown above but which may also be immersed in the liquid L. The fabric T then passes under the second of the rolls C while being sprayed with the liquid or emulsion with which the fabric is being treated. The fabric T then passes between a plurality of squeeze rolls D where a large portion of the excess of liquid is removed from the fabric before the fabric is passed into the heated drier E. The fabric T is passed through and doubled back a suitable number of times through the drier E. It is important to note that the rolls F at this point exert suiiicient tension upon the fabric T to retain the attenuation of the fabric T which was attained by pushing the fabric through the immersion process to the squeeze rolls. At no time, prior to the entry of the fabric into the drier E, is the fabric subjected to tension, the fabric being simply advanced by the action of the various rolls, a slight attenuation being imparted to the fabric by the twisting and untwisting action of the transversely oscillating rolls B and C in the presence of the liquid medium. It has been found desirable that a liquid medium in the form of an emulsion including polyvinyl acetate in such proportion as to cause the fabric to retain 3% to 6% solids from the emulsion be used.

A suitable frame 10 is shown in FIGURE 1 for supporting horizontal transversely disposed guide bars 11 which guide the fabric T as it is being withdrawn from,

the supply box 12. The fabric T is fed by passing same between a plurality of pairs of rolls each having a lower driven roll 13 and an upper superposed roll 14. An elongated rectangular frame broadly designated at 15 is shown constructed of suitable structural shapes for supporting the rolls described above as well as most of the various parts of the apparatus described below. Each of the rolls 14 is rotatably mounted in bearings 16 carried by bearing stands '17 which have fixed connection with the frame 15. The lower driven rolls 13 are rotatably mounted in bearings 18 also having fixed connection with the frame 15. The lower rolls 13, driven in a manner described below, rotate at a uniform peripheral speed so that the fabric T will be advanced by these rolls by frictional engagement therewith without the application of any tension whatever to the fabric T. A

The lower rolls 13 are shown paitially immersed in the liquid medium L held within a tray 19 which is supported bythe frame 15. The tray 19 has an extension thereof in the form of a relatively deep tray 20 in which the relatively large roll A is partially immersed in liquid L. A pair of transverse oscillating rolls B are shown completely immersed and positioned closely adjacent the lower portion of the relatively large roll A. The horizontal rolls are oscillated transversely by cams 21 which are disposed on a driven shaft 22 which is rotatably carried by a bearing block. The shaft 22 is driven by a suitable motor 23 through the chain drive 24. The rollers B are mounted on shafts 25 which carry cam followers for contacting the cams 21 which are shown in the form of eccentrically mounted discs. The shafts 25 are mount ed for rotation in a bearing stand 26 on the end adjacent the cams 21 and are carried by a similar bearing stand 27 on the ends remote from the cams. The shafts 25 are so carried by the bearing stand 27 that coil springs 28 normally urge the shafts to the right in FIGURE 2 so as to urge the cam followers 25a against the cam surface 25. The rolls C are carried on shafts 29 and are oscillated transversely in a similar manner by the cams 30 carried by the shaft 31 which is rotatably carried by a suitable bearing stand 31a (FIGURE 2). The shafts 29 are also mounted for rotation in the bearing stand 26 on one end adjacent the earns 30, are provided with cam followers 29a and are resiliently mounted on the other end by the springs 32. The shaft 31 is driven by a chain drive 24a from the shaft 22.

Referring again especially to FIGURE 1, it will be noted that the fabric T is fed beneath the relatively large roll A between the rolls B and the roll A. The rubbing action exerted on the fabric, particularly the warp yarns thereof, causes the fabric to open to admit the fluid so as to become saturated therewith. The interstices of the fabric are filled with liquid during this process. The fabric T is then fed upwardly over the relatively large roll A passing under the oscillating rolls C and then back over the oscillating rolls C to the squeeze rolls D. It should be noted particularly at this point that at no time during the previously described process has any tension whatever been placed upon the fabric T other than that imparted thereto by its own weight. During this time the interstices of the fabric have become thoroughly filled with the liquid medium and some attenuation has been imparted to the fabric due to the opening and closing of the fabric by the rubbing action of the transversely oscillating rolls B and C in the presence of the liquid medium L. During the passage of the fabric T between the second pair of superposed rolls 13 and 14 the fabric is subjected to a liquid bath from the sprayer 33 and again as the fabric is passing under the rolls C it is subjected to a bath of liquid from the sprayer 34. The sprayers 33 and 34 are supplied with liquid from the line 35 into which the liquid is pumped by the circulating pump 36. The pump 36 is driven by the motor 37 through the belt 38. The liquid flows from the relatively deep tray 20 as an overflow into the line 39 which carries the liquid to the circulating pump 36.

The squeeze rolls D include a first pair of superposed rolls 40 and 41 which are supported in a suitable bearing stand 42. A pair of threadable means 43 are provided for urging the bearing 44, which rotatably carries the upper roll 41 within the bearing stand 42 downwardly so that the roll 41 bears tightly against the lower roll 40 to squeeze the excess liquid medium from the fabric. A second pair of squeeze rolls 40 and 41 having similar mounting devices are shown with similar parts designated by like reference characters as used in connection with the first pair of squeeze rolls 40 and 41. A portion of the tray 20 extends forwardly as indicated at 45 and extends beneath both pairs of squeeze rolls B to convey the excess of fluid medium back into the relatively deep tray 20. Driving means is provided for the various rolls in the form of the motor 46 which by a chain drive 47 turns the shaft 48 which carries a bevel gear 49 on the forward end thereof. The bevel gear 49 drives a bevel gear 50 which through a gear train 51 drives the lower squeeze rolls 40. One of the squeeze rolls 40 drives a chain drive 52 (FIGURE 1) carried on the other side of the frame 15 remote from the gear train 51. The chain drive 52 drives the relatively large roll A which in turn drives the lower rolls 13 through chain drives 53 and 54 (FIG- URE 2).

The fabric T passes from the squeeze rolls D under the roll 55 and into the drier E. The roll 55 is rotatably carried by a suitable bearing 56 having connection with the frame 15. The fabric T passes through the drier and over and around the roll 57 and back in through the drier E and around the roll 59 which is rotatably mounted in a suitable bearing 60 having connection with the second bearing stand 42. The fabric T then passes for a third time through the drier E and over the roll 61 which is rotatably mounted in the bearing stand 62 carried by the frame 15. The fabric then passes over the rolls 63 and 64 which are carried in suitable bearing stands 65 and 66 respectively which have fixed connection with the frame 15. The fabric T is pressed against the upper surface of the rolls 63 and 64 by the roll 67 which is rotatably carried by the bearing stand 68. The bearing stand 68 has fixed connection with a support 69 which has pivotal connection with a bracket 70 as at 71. The free end of the support 69 is spring biased downwardly by the action of the coil spring 72 which is carried by the rod 73 which has suitable fixed connection with the frame 15. The tension of the spring 72 is adjusted by the wing nut 74 which confines the spring 72 between it and the upper portion of the support 69.

During the passage of the fabric T through the drier E, sufiicient tension is exerted thereon by the various rolls described above as associated with the drier E to maintain the same degree of attenuation which was imparted to the fabric by the immersion process described prior to the fabric T passing through the squeeze rolls D. The rolls 63 and 64 are driven by the shaft 48 (FIGURE 2) which extends along the frame 15 and is supported by the bearings 48a. The bevel gears 63a and 64a drive the shafts 63 and 64 respectively through suitable meshing bevel gears 63b and 64b. The rolls 63 and 64 are driven at a suitable speed relative to the other rolls to provide the requisite tension to prevent substantial contraction of the fabric T but without permitting substantial further attenuation.

Referring especially now to FIGURE 3, the drier E which is supported by the frame 15 is shown to be of rectangular construct-ion including sheet metal sides 75 and a top 76 which is hinged as at 77 for access to the drier E. The bottom 78 is constructed of suitable sheet material and a baffle 79 is provided for receiving heated air which is blown into the duct formed thereby. The hot air is circulated through the drier E by the duct formed by the bottom 78 and the baffle 79 and returns through the duct 80 (FIGURE 1) where it is reheated by the burner 81. The burner 81 is supplied with fuel from the tank 82 through the line 83. The hot air is then projected by the blower 84 into the supply duct 85 which introduces air into the drier E under the baffle 79. The blower 84 is driven by the motor 86 by the belt drive 87.

After passing over the rolls 63 and 64 under the roll 67, the fabric then passes over a guide roll 88 which is rotatably mounted in a suitable bearing stand 89 carried by an extension of the frame 15 which is designated at 96 and which is considerably higher than the frame 15 and substantially box-like so as to rotatably carry rollers 91 therein so as to guide the fabric T into suitable receptacles 92 provided therefor.

It is important to note that at no time during the process described does stretching of the fabric by tension take place. The fabric is attenuated somewhat by advancing the fabric forward by the various rolls and during the drying step some tension is applied to the fabric but only sufficient tension is applied to maintain the degree of attenuation which is obtained during the impregnating process. The various gears and roll drives mentioned are adjusted so that the peripheral speed of the rolls are all the same with the exception of the rolls which are described as necessary to maintain the attenuation of the fabric during the drying process and it is evident that their peripheral speed must be slightly greater than that of the driving rolls preceding them to compensate for the attenuation of the fabric but the same with respect to each other thus taking up and maintaining the increased length of fabric. The driven squeeze rolls D feed the fabric into the drier and are thus driven slightly faster together with the rolls within the drier, the rolls D and those within the drier turning at the same peripheral speed.

While any liquid impregnating agent may be used with success, it has been found by experiments that a preferred emulsion consists of about 13% solids according to the following composition:

Lbs. Polyvinyl acetate 9.00 Ammonia (for correcting pH) .75 A mildew inhibitor 2.375 Geon 1.00 A plasticizer for geon .605 Wetting oil 1.25 Water 75.00

It has been found that the use of the above emulsion on a narrow fabric in the form of greige goods results in the fabric retaining about 4% solids by weight. It has been found that the retention of 3% to 6% solids by weight by the fabric is desirable because a percentage of below 3% is not SllfilClEIlt to be effective while about 5% requires the use of emulsion which would be too pasty and thick for use with the method and apparatus of the invention. It has been found that the use of emulsions containing about solids by Weight in the emulsion produces about 3% solids in the fabric while the use of emulsions containing about 20% by weight solids produces a retention of about 6% solids in the fabric and that above 20% solids produces an emulsion which is too thick for use in the method. If desired, cellulose acetate, cork or other suitable static inhibitors may be added to further prevent the attraction of lint.

Using an emulsion as described above on narrow fabrics in the form of greige goods, the stretch at break of spun cotton which is between 18 to 25%, spun nylon which is about 52%, spun Dacron which is about 30% and mixed blends which is between 18 to 40% were all reduced to between 3 and 6% with the exception of the spun nylon which was reduced to about 20%. These fabrics had added strength and wearability and showed a freedom from static attraction which normally causes lint to adhere thereto. The gauge of the narrow fabric was also reduced.

In carrying out the process it has been found that a temperature of about 380 F. is a desirable temperature because it is sufliciently elevated to result in relatively rapid drying but is not sufiiciently elevated to damage even relatively thin Dacron. It has been found that the gains in length without stretching were achieved in the neighborhood of from 5 to 20%.

It is thus seen that a method has been provided for effectively increasing the break strength of narrow fabrics. The use of the method also results in increased yarn compaction which produces an unusually smooth surface. When tape for use as spindle drives is treated, the spindle whorl grip is improved so that little or no slippage occurs between the tape and the metal surface. A particularly desirable result of the invention is the reduction of stretch of the tape which is especially desirable where the tape is being used as a drive.

The foregoing disclosure and description of the invention is illustrative and explanatory thereof and changes and variations will occur of those skilled in the art which may be made within the scope of the appended claims without departing from the spirit of the invention.

What is claimed is:

1. The method of impregnating attenuating and drying narrow woven fabric including, advancing the fabric by contact with a plurality of driven rolls so that the fabric travels forwardly in a substantially relaxed state, applying an excess of liquid with which it is desired to treat the fabric to said fabric, subjecting the fabric to the action of transversely oscillating rolls in the presence of the excess of liquid so as to expose the interstices of the fabric to the liquid and to attenuate the fabric, moving said fabric into a drier where a suificiently elevated temperature obtains for relatively rapidly drying the fabric but where such temperature is sufiiciently low to avoid damage to the fabric, and preventing contraction of said fabric while the fabric is in the drier to prevent the loss of attenuation of the fabric achieved by treatment with the liquid but without permitting further attenuation by taking up and maintaining the increased length of fabric, whereby the stretch at break of the fabric may be reduced and held within desirable limits.

2. The method set forth in claim 1, in which said liquid is an emulsion including about 10% to 20% by weight of polyvinyl acetate.

3. The method set forth in claim 2, in which the temperature obtaining in the drier is about 380 F.

4. The method of impregnating, attenuating, and drying narrow woven fabric including, advancing the fabric by contact with a plurality of driven rollers so that the fabric travels forwardly in a substantially relaxed state, immersing said fabric in a bath of liquid with which it is desired to treat the fabric, subjecting the fabric to the action of transversely oscillating rolls while immersed in the liquid bath so as to expose the interstices of the fabric to the liquid and to attenuate the fabric, moving said fabric into a drier where a sufificiently elevated temperature obtains for relatively rapidly drying the fabric but where such temperature is sufficiently low to avoid damage to the fabric, and preventing contraction of said fabric while the fabric is in the drier to prevent the loss of attenuation of the fabric achieved by treatment with the liquid but without permitting further attenuation by taking up and maintaining the increased length of fabric, whereby the stretch at break of the fabric may be reduced and held within desirable limits.

5. The method of impregnating, attenuating, and drying narrow woven fabric so as to improve the wearing characteristics of the fabric including, advancing the fabric by contact with a plurality of driven rollers so that the fabric travels forwardly in a substantially relaxed state, moving the fabric in the above manner past a sub merged portion of a relatively large roll which is at least partially submerged in a liquid medium with which it is desired to treat the fabric, subjecting the fabric to the rubbing action of a pair of axially oscillating rolls positioned closely adjacent said relatively large roll while the fabric is submerged in the liquid so as to twist the warp yarn from which the woven fabric is constructed to make the fabric accessible to the liquid to thereby obtain an attenuation of the fabric, moving said fabric into a drier where a sufficiently elevated temperature obtains for relatively rapidly drying the fabric but where such temperature is within desirable limits sufficiently low to avoid damage to the fabric and sufliciently elevated to accomplish relatively rapid drying, and preventing contraction of said fabric while the fabric is in the drier to prevent the loss of attenuation of the fabric achieved by treatment with the liquid but without permitting further attenuation of the fabric by taking up and maintaining the increased length of fabric, whereby the stretch at break of the fabric may be reduced and held within desirable 6. The method of impregnating, attenuating and drying narrow woven fabric including, advancing the fabric in a substantially relaxed state, applying an excess of liquid with which it is desired to treat the fabric to said fabric, subjecting the fabric to the action of transversely oscillating rolls in the presence of the excess of liquid so as to expose the interstices of the fabric to the liquid and to attenuate the fabric, moving said fabric in a substantially relaxed state into a drier where a sufliciently elevated temperature obtains for relatively rapidly drying the fabric but where such temperature is sufiiciently low to avoid damage to the fabric, and preventing contraction of said fabric while the fabric is in the drier to prevent the loss of attenuation of the fabric achieved by treatment with the liquid but without permitting further attenuation, whereby the stretch at break of the fabric may be reduced and held within desirable limits.

7. The method of impregnating, attenuating and diyiug narrow Woven fabric including, advancing the fabric by contact with a plurality of driven rolls all turning at the same peripheral speed so that the fabric travels forwardly in a substantially relaxed state, applying an excess of liquid with which it is desired to treat the fabric to said fabric, subjecting the fabric to the action of transversely oscillating rolls in the presence of the excess of liquid so as to expose the interstices of the fabric to the liquid and to attenuate the fabric, subjecting said fabric to the action of squeeze rolls driven slightly faster than the first mentioned driven rolls taking up the increased length of fabric resulting from attenuation and moving said fabric in a substantially relaxed state into a drier where a sutficiently elevated temperature obtains for relatively rapidly drying the fabric but where such tem-.

perature is sufiiciently low to avoid damage to the fabric,

and preventing contraction of said fabric while the fabric is in the drier to prevent the loss of attenuation of the fabric achieved by treatment with the liquid but without permitting further attenuation by taking up and maintaining the increased length of fabric, whereby the stretch at break of the fabric may be reduced and held within desirable limits.

References Cited in the tile of this patent

Images