US3077657A - Nonwoven fabric - Google Patents

Description

Feb. 19, 1963 R. D. WELLS v 3,077,657

NONWOVEN FABRIC Original Filed Sept. 29, 1959 2 Sheets-Sheet 1 FIG. I FlG.-2 FIG. 3,,53 5 ooooc S2 HIiH i o o o o e I H ii 5 I l we l6 16 52 w w F|G.8 3

F F"""!' 3 we T INVENTOR wz i f RICHARD 0. WELLS l i 1 (1%? Quiz L- L L ATTORNEY Feb. 19, 1963 RQD. WELLS 3,077,657

NONWOVEN FABRIC Original Filed Sept. 29, 1959 2 Sheets-Sheet 2 FIG. I8

FIG. 19 4e mm g -2: 58 7. l 70 7| .7 1-

INVENTOR RICHABP D. WELLS ATTORNEY United States Patent 3,ii'7'7,657 IJGNWGVEN FABREC Richard 3. Wells, Westwood, Mass assignor to Crampton dz Knowles Corporation, Worcester, Mass, a corporation of Massachnsetts @riginal application Sept. 29, 1959, Scr. No. 843,151, new Patent No. 3,652,943, dated Sept. 11, 1962. Divided and this appiication Feb. 19, 1962, ar. No. 123,929 2 s'liairns. or. 28-49) This application is a division of my copending application Serial No. 843,151 filed September 29, 1959, now Patent 3,052,948, which application relates to a textile product or structure made by needling a fibrous web Of loosely assembled fibers. This divisional application relates particularly to a nonwoven fabric shown but not claimed in the above identified application.

In the making of so-called nonwoven fabrics there is ordinarily employed some form of adhesive to hold the fibers together, or when thermoplastic fibers are use they are stuck to each other by a heating process. Such fabrics, however, do not have the same feel or texture commonly found in knit and woven fabrics. In order to attain a more acceptable feel, it is an important object of the invention to eliminate the use of objectionable amounts of adhesive or thermoplastic fibers by making a nonwoven fabric wherein there is a mechanical interlocking or bonding of fibers.

The usual batt or web of fibers ordinarily does not have sufficient strength to withstand the strains of ordinary usage and it is a further object of the invention to gather certain of the fibers into reenforcing yarn-like structures which act to strengthen and reenforce the web or batt.

By way of illustrating the invention, five types of structures are set forth in one of which the reenforcing zones or structures are transverse of the plane of the web and extend from at least one surface of the Web into the latter in such manner as to gather or twist fibers in concentrations which are connected to each other by fibers which partake only partly of the twisted concentrations. In the second form of the invention reenforcing yarn-like structures are formed lengthwise in a single batt or web of fibers, and in the third form two batts or webs are brought into tangential or at least surface contact with each other and the rcenforcing structures are made from fibers drawn from both webs. In the fourth form reenforcing structures are formed on both sides of a web. in the fifth form the fibers are gathered together to form a yarn-like structure which is not necessarily connected to any similar structure but can be used either as a step for further treatment to produce yarns or can be used directly as produced as will be set forth hereinafter.

in order to produce the reenforcing yarn-like structures it is an important object of the invention to subject the fibers in localized zones of the web to rotary action which will coil at least some of the fibers on themselves and wherein some of the coiled fibers extend into adjacent areas of the web to have frictional contact with other fibers not necessarily entangled in the yarn structure.

it is a further object of the invention to use fibers some of which will have a length suflicient to extend from one reenforcing structure to an adjacent similar structure and become coiled into both structures so that the lateral strength of the web is increased. A still further object of the invention is to make a continuous yarn-like structure from a web or batt which has been split into a number of separate tapes or ribbons from each of which the fibers are collected in a manner to form individual yarn-like structures.

Many nonwoven fabrics lack the property of drape and are also only slightly elastic in any direction, particularly lengthwise and crosswise. It is an important object of the present invention to make a product in the nature of a nonwoven fabric which is capable of elastic stretch lengthwise and also crosswise.

This latter characteristic of the fabric is attained by coiling some of the fibers helically so that the yarn-like structure has lengthwise elasticity and spirally coiling other fibers, or parts of those coiled helically, to permit uncoiling to provide transverse elasticity.

In the accompanying drawings wherein examples are given of each of the five types of structures already mentioned,

FIG. 1 is a diagrammatic combined plan and side view of a fabric made according to the first form of the invention wherein short reenforcing structures are assembled out of fibers in the web and extend at least partway through the web from one side to the other.

FIG. 2 is a diagrammatic view similar to FIG. 1 but wherein lengthwise yarn-like structures have been formed in a single web of fibers,

FIG. 3 is a diagrammatic view similar to FIG. 2 but wherein the web has been made by joining two distinct Webs by reenforcing yarn-like structures located between the two webs and having their fibers drawn from each of the webs so that the latter are closely bonded to each other,

FIG. 4 is a diagrammatic view showing an end of a fabric similar to that shown in FIG. 2 but with a row of reenforcing yarn-like structures on both sides thereof,

FIG. 5 is a diagrammatic view showing a single yarnlike structure formed as such without reference to a fabric,

FIG. 6 is an enlarged diagrammatic section on line 6-6, FIG. 2,

FIG. 7 is a diagrammatic View looking in the direction of arrow 7, FIG. 6, illustrating the manner in which a single fiber can be joined to two adjacent yarn-like structures,

FIG. 8 is an enlarged diagrammatic section on line 8-8, FIG. 3, showing the manner in which two webs can be joined as contemplated in the third form,

FIG. 9 is a view similar to FIG. 6 but showing a modified form of fiber relationship,

FIG. 10 is similar to FIG. 8 showing a variation thereof,

FIG. 11 diagrammatically shows a fabric such for instance as set forth in FIG. 2 in normal size in full lines and in stretched size in dotted lines,

FIGS. 12 to 15 diagrammatically show fabrics of different forms but all of the general type shown in FIG. 4,

FIG. 16 is a diagrammatic plan view of a fabric made according to the invention showing various fiber relations,

FIG. 17 is a side elevation in diagrammatic form showing a machine for producing the type of fabric shown in FIG. 1,

F G. 18 is a diagrammatic elevation of a machine looking in the direction of the feed of the web to be acted on for producing, for instance, the types of fabrics shown in FIGS. 2, 3 or 4 FIG. 19 is a diagrammatic side view looking in the direction of arrow 19, FIG. 18,

FIG. 20 is a diagrammatic view showing part of the structure shown in FIG. 19 in a somewhat different position for producing, for instance, the type of fabric shown more specifically in FIG. 2,

FI 21 is a diagrammatic view showing structure and method for producing the fabric shown in FIG. 4,

FiG. 22 is a diagrammatic plan view showing a variation in the structure shown in F168. 18 and 19 whereby the needles turn in the same direction, and

FIG. 23 is a diagrammatic plan view looking in the seas-ear direction of arrow 23, FIG. 19, parts being omitted, showing the web split into a number of separate tapes or ribbons for forming the single structure shown in FIG. 5.

Referring more particularly to FIG. 17 which diagrammatically shows a machine to produce the type of fabric illustrated in FIG. 1, frame it has upright'posts 11 which supports table 12 having a bearing 13 slidable on each post 11. Extending over and secured in fixed position on the table 12 is a web supporting plate 14 provided with perforations 15 to register with other perforations 16 in a second plate 17 mounted over the plate 14. The plate 17 is mounted for rising and falling motion and has end supports 13 which normally rest on fixed stops 19 which limit down motion of plate 17.

The machine has a shaft '20 driven in any convenient manner to which is secured a crank 21 connected by links 22 to feed arms 23 rockable about fixed studs 24. Each arm 23 has a feed pawl 25 which meshes with a ratchet wheel 26 rotatable on the corresponding stud 2d and sesured to a pulley 27. Each pulley drives a belt 28, the belt at the left driving a feed pulley 29 for a flexible web feeding belt '30 trained around an idler pulley 31. The belt 23 at the right drives a pulley 32 for a flexible takeoff belt 33 trained around an idler pulley 34. A take-off board 35 receives material fed to it by belt 33. Hold pawls 36 prevent retrograde motion of ratchet wheels 26.

A cam 40 is secured to shaft '26 and has a low dwell 41, an incline 42, a high point 43 and a decline 44. The cam engages a roll 45 rotatably mounted on the underside of table 12. Rotatable needles are normally located above plate 17 in register with the openings 16 in the top plate and 15 in the bottom plate. Each needle N at the lower end thereof has a slightly offset barb B for engagement with the fibers of a web or batt W1.

In the operation of the machine shown in FIG. 17 the web or batt W, which is made of a large number of loosely assembled fibers, is fed by belt 30 to the space between plates 14 and 17 when the low area 41 of cam 40 has let the roll 45 and table 12 down to their low positions. At this time the crank arm 21 will be giving feeding strokes to pawls 25 to advance belts 30 and 33 to feed the web between the plates 14 and 17. When the crank arm has made a half turn and starts a reverse motion of the feed pawls 25 the cam 40 will lift the table 12 and plate 14 to elevate the web against the plate 17 and lift it off the supporting stops 19, thereby subjecting the web to some restraint. As the cam continues to turn the plates 14 and I7 and also the web rise so that the needles N can pass through the holes 16 and rotate in the web to gather fibers into coiled form at spaced intervals as shown for instance at S1, FIG. 1. The holes 15 are provided in plate 14 to permit the needles to go entirely through the web if this is desired. As the crank 21 continues the idle motion of the pawls the cam 4t} continues to turn and lower the plate 14. The plate 17, by its weight, will move the web down away from the needles and come to rest on the stops 19. This will complete the operation with respect to a section of the web and the belt 33 will then move the treated web onto the take-off table or board 35 as the belt 3% feeds the next section of web between plates 14 and 17. In this way the web is provided with transverse reenforcing areas of coiled fibers some at least of which extend into adjacent parts of the nontreated web to have frictional holding contact therewith.

The needles may be mounted and operated as shown for instance in FIGS. 18 and 19. In FIG. 18 the driving motor M has a drive pulley 46 connected by belt 47 to driven pulley 43 secured to the upper end of a vertical shaft 49. The shaft 49 extends down through a top plate 54 and has secured thereto a gear 51 and continues be yond the latter and has mounted on the lower end thereof a chuck 52 in which the upper end or shank of a needle N is secured. Other chucks 53 similar to chuck 52 are mounted on vertical shafts 54 each having a gear 55 secured thereto. Thegears 51 and 55 mesh, adjacent gears 4t and needles turning in opposite directions. The vertical position of the chucks is determined by a second plate 56 vertically adjustable by nuts 57 on upright screws 58 the lower ends of which are secured to the frame 5?.

As the motor M turns it causes rotation of shaft 49 which in turn causes rotation of all of the needles and this arrangement can, if desired, be utilized to drive the needles N which are shown in FIG. 17. The lower end of each needle is provided with the barb B offset slightly from the shank of the needle and it is the barb on each needle which gathers certain of the fibers into the yarn-like structures 51 of FIG. 1. The shafts 49 and 54 have coliets it which engage the under side of plate 56 to limit upward motion of the chucks and needles. The gears which are secured to the shafts rest on collars or washers 61 supported by the top of plate 56. In this way vertical adjustment of the plate 56 determines the positions of the lower ends of the needles.

When making the fabric shown in FIG. 2 from a single web of fibers the web W2 is fed onto a drum 65, see FIG. 20, which can be turned by means of gear reducer 66 shown in FIG. 18 as being driven by a connecting shaft 67 turned by the motor 'M. The needles shown in FIG. 20 have been disposed to operate at an angle but in other respects the driving mechanism will be as already described in connection with FIGS. 18 and 19. The web W2 is fed in the direction of arrow at, E6. 20, and the free ends of the needles terminate close to the friction, soft rubber, surface 68 of the drum or cylinderdfi. The ends of the needles have the barbs on them extended into the web and rotate at a speed sumcient to gather fibers into yarn-like assemblages or coils S2 which run lengthwise of the web, these yarn-like structures being to the left of the needle as viewed in FIG. 20.

When producing the fabric shown in FIG. 3 the needles can have the disposition shown in FIGS. 18 and 19, that i upright with their barbed lower ends terminating near the nip between two cylinders 7% and '71 which turn in opposite directions as indicated by arrow b and 0, FIG. 19. These are the drums which are shown in FIGS. 18 and 19 and are driven by the gear reducer 66 so that their angular speed is considerably less than the rotational speed of the needles. Two webs WSA and WSB are trained respectively over the upper parts of the cylinders 78 and 71 which may be similar to the drum or cylinder 65. As the drums 7t} and 7?. turn they draw the webs down to the space or nip between them and cause the two webs to come into surface engagement with each other at a point approximately at the lower end of the needles. As the nedles turn their barbs collect fibers from each of the two webs WEA and W313 into yarn-like structure S3 and in this way unite the two webs into a single web W3 which corresponds to the web shown in FIG. 3. The lower part of FIG. 3 shows the web W3A as at the top and the web WSB as at the bottom with the yarn-like structures S3 connecting these two webs to form the single united web W3. As shown in FIG. 19 the fabric W3 is led down around guide rolls 75 and then to a wind-up roll 7% which can be driven from the reducer 66 somewhat after the manner of driving cloth rolls in looms. A similar wind-up drum or roll can be provided to collect each of the various products set forth herein.

Experience shows that the barbs B can occupy several different positions with respect to the broken line L showing the centers of the two cylinders 7d and 71, that is, they can be slightly above the line, on it, or slightly below it. Whatever their position it is desirable that the two webs be under some compression and that the barbs turn on axes which lie on the plane of contact of adjacent surfaces of the two webs W3A and W313. The single web shown in FIG. 2 can be passed between the two rolls 7d and 71 if desired, and it need not necessarily be made as indicated in FIG. 20.

FIG. 21 illustrates diagrammatically the structure by which the fabric shown in FIG. 4 is produced. In FlG.

' be described but they are ac /ass? 2l a roll 9% feeds a web W4 to the first set of needles 91 which produces yarn-like structures Sell on one side of the web W4. The latter then moves to a second roll 92 and a second set of needles 93 produces yarn-like structures S42 on the opposite side of the web. The latter is then led over a roll 94 to a wind-up mechanism (not shown) similar to that shown in FIG. 19.

FIG. 22 shows how the needles of a bank can all be rotated in the same direction. Plate )5 similar to plate 56 replaces the latter and has rotatable thereon pinions 96 which mesh with gears 97 smaller in diameter than gears 52. and 55. A central vertical shaft 98 is similar to shaft is and other shafts 9? are similar to shafts 54. In this way all the needles turn in the same direction as distinguished from the form shown in FIGS. 18 and 19 wherein adjacent needles turn in opposite directions.

By turning the needles in the same direction, all the fibers of a web are coiled in one direction as opposed to fibers coiled in opposite directions with respect to each other when the mechanism of FIG. 18 is employed as set forth hereinafter.

The single ya rn like structures such as shown in FIG. 5 can be produced as set forth in FIG. 23 wherein the web, before reaching the feed roll liltl, has been split into thin tapes or ribbons -1. A needle 16-2 is provided for each tape and may be mounted and operated as already described. As roll 1% and the needles W2 turn the fibers of the tapes will be gathered into coiled forms S5, but unlike the previously described forms, the yarn-like structures in this instance are separate and do not form parts of a. fabric.

The different mechanisms briefly described hereinbefore form no part of the present invention and are fully described and set forth in my copending application cited above.

When making the nonwoven fabrics set forth herein, the fibers in the web may be disposed in various ways and, because of this, the manner in which the barbs on the needles engage the fibers will vary and therefore have more efiect on some fibers than others. If the fibers are of a preferred random distribution in the web some of them will approach a needle parallel to the direction of feed of the web and be little affected by the needle. Other fibers may be disposed crosswise of the web feed and will be engaged either near an end or at a point more or less midway of the ends. Still other fibers will be oblique to the direction of travel and may have one end engaged by one needle and later have the other end engaged by an adjacent needle. Other fibers may not be directly engaged by any needle but will be irictionally touching a fiber that is acted on by a needle and to some extent have its position changed by the first fiber. Other fibers may be transversely disposed but not be affected by a needle. No attempt is made herein to show all possible arrangements and dispositions which the fibers can occupy as hey move toward the needles as the web is drawn forwardly. A 'tew specific fiber relations will not by any means to be considered as anything more than representative examples.

The fibers are acted on by two forces one of which moves the web in an onward or forward direction and the other of which arises from the rotating needles and produces the coiling of the fibers. The onward feed tends to draw the coils into lengthwise helical form and the needles tend to arrange parts at least of the fibers into spiral forrn. Many of t. e fibers are therefore both helically and spirally coiled and can be stretched lengthwise due to the helical coiling and can be partly uncoiled when the fabric is stretched crosswise due to the spiral coiling. Some uncoiling can occur in the helically wound parts of the fibers incident to crosswise stretch.

in FIG. 6 a single fiber lid is shown as connected to two adjacent structures S2 between which a straight part ill of the fiber extends. The left-hand end of fiber Hil has been coiled in a counterclockwise direction and the right-hand end in a clockwise direction by reason of the opposite direction of rotation of the needles with reference to FIG. 18. FIG. 7 shows one possible arrangement of the helically coiled parts 112 and 113 of the fiber ill FIG. 8 shows a fiber 115 disposed similar to fiber lilo except that its structures S3 are common to the two webs WA and WE which they join. FIG. 6 shows two fibers 118 and Ill? caught in the right and loft-hand structures S2 respectively and extending into adjacent parts of the fabric, or to adjacent similar structures (not shown). Similarly, fibers lit) and 121 extend to the right and left from structures S3 in FIG. 8.

FIG. 9 is a view similar to FIG. 6 except that the yarnlikc structures are produced by needles all of which turn in the same direction, see PEG. 22, and FIG. 10 is similar to FIG. 8 but with the same exception. The fiber 125 in FIG. 9 passes from the top of one of the coiled structures down through the web to the bottom of the adjacent structure, this being true also in FIG. 10. In FIG. 9 fibers 126 are similar to fibers 118 and 119, PEG. 6, and in FIG. 10 two fibers 127 and 128, one from the upper web WA and the other from the lower web WE are shown connected to the lefthand yarn structure S3.

PEG. 11 illustrates diagrammatically a valuable property possessed by the fabrics already described. Taking the second fabric as an example, and referring to P165. 6 and 7, the fabric W2 may have an original length e but because of the helical coiling shown in FIG. 7 the length can be stretched or increased to f. The original width g can be increased .to the width h due to uncoiling of the spirals shown in FIG. 6, or to uncoiling of the helices. On release of the stretching forces the helical and spiral coils will tend to return to their original forms. The fabric is thus seen to possess considerable elasticity due to the coiling of the fibers. This property is possessed by other of the fabrics, such as W3 and W4.

In the fabric W1 the yarn-like structures S1 are short and transverse of the plane of the web, but these structures S1 are spirally and helically coiled and can unwind in response to lengthwise and transverse stretching forces.

When a single web is being made, as in PEG. 20, or when being fed by one of the drums in FIG. 19, the yarnlike structure S2 is likely to be nearer one side of the web than the other and it is for this reason that the diagrammatically illustrated mechanism in FIG. 21 can produce the fabric W4. FIGS. 12-15 show diagrammatically some of the forms of fabric W4 with particular reference to the direction of rotation of the needles shown in FIG. 21.

In FIG. 12 the direction of coiling for the top structures S41 is clockwise whereas for the lower structures S42 the direction is counterclockwise. The structures S41 and S42 are staggered as shown so that if the fabric is subiected to a later compressing operation the structures of the two series can nest close to or between each other.

In HS. 13 the top series S41 is made by needles operated as in H6. 18 whereas the bottom series is made by needles turning as for the bottom series in FlG. 12.

In FIG. 14 both top and bottom series are coiled clockwise, while in PK 15 both series are formed by needles which rotate in opposite directions for each series.

As already mentioned the fibers can assume a great many different positions and relations only a few of which will be described in connection with FIG. 16. In that figure a fiber 136 is shown coiled into the left-hand structure S2 and having a free end 131 which has frictional holding relation with the free end 132 of another fiber 33 coiled into the central structure S2. Another fiber 154 coiled into the left-hand structure has a free end 135 which has frictional holding relation with an uncoiled fiber 136 lying between two adjacent structures but not directly connected to either of them. Other fibers 137 are not connected directly to any structure S2, and fiber 138 similar to fiber 11b is shown as frictionally engaged aortas? with another fiber 139 not connected to any structure S2. Other of the fabrics can have similar fiber relations.

In FIG. 12 the series of structures S41 and S42 are shown as cross connected by fibers Mt which, like others similar to them but not shown, tend to bind the two series together, the ends of fiber i l-l} being coiled into structures on opposite sides of the Web. Similarly, fibers 141, 142 and 143 in FIGS. 14, 14 and 15 respectively bind the structures S41 and S42 in each form to each other.

In the making of a fabric, a web containing 25% viscose fibers and 75% acetate fibers was used. Tests were made of samples of the web one inch wide, six inches long, and about one-quarter inch thick. The tests showed an average breaking strength of the unprocessed web samples of 4.3 grams, whereas the processed samples containing a single lengthwise yarn-like structure, as S2, had a breaking stren th averaging 23.4 grams. The coiling of the fibers therefore resulted in an increase of more than 500% in the strength of the Web. Both the processed and unprocessed samples had in them approximately the same number of fibers.

The web from which the fabric is produced is not limited to the specific types of fibers mentioned and the fibers can be of difierent lengths and may be either oriented, as lengthwise of the web, or placed at random.

The separate tape or ribbon webs shown in FIG. 23 can be cut or otherwise derived from a wider web in any approved manner. One method could, for instance, be similar to the procedure set forth in American Wool Handbook, 1948, published by Textile Book Publishers, Inc, New York City, the chapter on Blending and Woolen Carding, section on Tape Condensers.

The yarn-like structure shown in PEG. can be produced by a needle operating at approximately 400 rpm. while each or" the tapes 101 is fed at about two feet per minute. Other speeds of needle rotation and tape or web feed were found to be satisfactory and the smaller the ofiset of the point of the barb from the shank axis of the needle the smaller will be the diameter of the yarn-like structure. The barbs B of course are honed in order to insure clearance of the structures 81-55 from the needles as the webs are advanced.

While reference has been made to the spiral arrangement of parts at least of the coiled fibers, it is to be understood that the feature set forth in FIG. 11 for instance, especially the transverse stretching, can be derived from the helically wound parts of the fibers as well as any parts which may be spirally wound. Since the coil arrangement is made around a needle having an appreciable diameter the coils at one point in their formation may be hollow, but it is found that as the operation proceeds the yarn-like structures tighten on themselves so that in the finished product there is only a small axial hollow observable in the structures.

In all forms of the invention there is a gathering or" fibers or parts thereof from a web after which the fibers or parts thereof are subjected to rotary action to orient them partly spirally nad partly helically. In the form shown in FIG. 1 the coil structures are shown substantially at right angles to the plate of the web but they could, if desired, be disposed at an angle by an appropriate modification of the machine shown in FIG. 17. In other worms the Web at the zone of operation is moving more or less parallel to the axis of the needles and for this reason the web can be moved continuously instead of intermittently as contemplated in FIG. 17. The single web shown in PEG. 2 can be made either as suggested in FIG. 20' or by the structure shown in FIG. 19 wherein only one web will be fed over one of the drums.

Although the form of product shown in FIG. 5 has been described as made from tapes or ribbons of fibers formed as such before reaching the needles, it may also be made by moving a wide web to the needles and cutting it into tapes at the needles. In fact, cutting may be omitted and reliance placed on the needles to separate the structures S5 from the web.

In any of the coils shown in any of the forms described the fibers may be set in the coiled configuration by means well known in textile arts such as the heat-setting of thermoplastic fibers or chemical treatments which produce memory efiects, thus enhancing the elastic behavior of the web system as set forth in FIG. 6.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be made, what is claimed is:

l. A nonwoven fabric formed from a web of loosely assembled fibers having lengthwise transversely spaced coiled groups of fibers forming yarn-like structures on opposite sides of the web and having some of its fibers coiled into two of said structures on opposite sides of the web.

2. A fabric set forth in claim 1 wherein the yarn-like structures on one side of the web are staggered transversely thereof with respect to the structures on the other side of the web.

No references cited.

Claims (1)

1. A NONWOVEN FABRIC FORMED FROM A WEB OF LOOSELY ASSEMBLED FIBERS HAVING LENGTHWISE TRANSVERSELY SPACED COILED GROUPS OF FIBERS FORMING YARN-LIKE STRUCTURES ON OPPOSITE SIDES OF THE WEB AND HAVING SOME OF ITS FIBERS COILED INTO TWO OF SAID STRUCTURES ON OPPOSITE SIDES OF THE WEB.

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