US3546722A - Cushioning material - Google Patents

Description

Dec. 15,1970 &AWATSON 3546322 CUSHIONING MATERIAL 3 Sheets-Sheet 1 Original Filed Dec. 30, 1964 N n w INVENTOR GEORGE A. WATSON A'ITORNEY Dec. 15, 1970 e. A. WATSON &546.722

CUSHIONING MATERIAL Original Filed Dec. 30, 1964 3 Sheets-Sheet 2 INVENTOR GEORGE A. WATSON ATTORNEY D 1970 G. A. WATSON V 3,546,722

CUSHIONING MATERIAL 3 Sheets-Sheet i Original Filed Dec. 30, 1964 ACTUATING 5 j INVENTOR 4 g GEORGE A; WATSON ATTOR Y Unted States Patent O "ice 3,546,722 CUSHIONING MATERIAL George A. Watson, Charlotte, N.C., assignor to Celanese Corporation, New York, N.Y., a Corporation of Delaware Application Dec. 30, 1964, Ser. No. 422,341, now Patent No. 3,423,795, which is a continuation-in-part of applications Ser. No. 382,018 and Ser. No. 382,263, both July 13, 1964. Divided and this application July 22, 1968, Ser. No. 761,?:76

Int. Cl. A47q 9/00 U.S. CL 5-337 6 Claims ABSTRACT OF THE DISCLOSURE A pillow comprising a randomly crumbled cohesve web of deregistered continuous substantially parallel filaments.

This is a division of Ser. No. 422,34l, filed Dec. 30, 1964, now U.S. Letters Patent, 3,423,795, filed Jan. 28, 1969, which patent is a continuation-in-part application of application Ser. No. 382,0l8, filed July 13, 1964, now Pat. 3,328,850 and application Ser. No. 382,263, filed July 13, 1964, now abandoned.

This invention relates to the production of batts suitable for cushioning and relates more particularly to the production of pillows from webs of parallel crimped continuous filaments.

A great many pillows are now stuffed with battings made of polyester fibers, e.g. fibers of terephthalate polyesters such as polyethylene terephthalate. Conventionally the stuffing is made from a mass of crimped staple fibers by a process in which one or more webs of the fibers are formed on a carding machine (after the usual preliminary Operations of opening the bales of staple fiber and picking the opened mass to prepare it for carding). These webs, which are conventionally termed card webs," are fed onto a continuously moving belt on -which the desired thickness of batting is built up. Thus a number of carding machines may be employed to feed a corresponding number of card webs, one above the other, onto the belt, or a single carding machine may be coupled to a suitable cross-laying device to produce a cross-layed web of the desired thickness on the belt. The resulting batting which may, for example, be about 26 inches wide and which may wegh about 8 ounces per square yard, is then torn along transverse lines suitably spaced along its length to produce short batts, each containing enough stuffing material for one pillow (e.g. about 20 ounces of stulfing material), after which each batt is rolled up and stufed ino the pillow ticking.

It is an object of this invention to provide a method and apparatus for producing pillows from polyester filamentary material, which will produce such pillows much more rapidly than is possiblewth the conventional process now employed, and which will produce pillows of higher quality and better properties than the conventional polyester fiber-filled products.

Another object is the provision of novel batts suitable for cushioning and of new, comfortable, lightweight pillows.

Other objects of this invention will be apparent from the following detailed description and claims.

This application is a continuation-in-part of my earlier application 382,263, of July 13, 1964, whose entire disclosure is heren incorporated by reference.

In accordance with one aspect of this invention, pillows are produced from a tow of a great many crimped 3,546,722 Patented Dec. 15, 1970 continuous polyester filaments by continuously deregistering the crimps of the tow and thereby opening the tow, continuously spreading the tow to form a continuous light cohesve web of parallel crimped filaments, continuously feeding said web against a barrier to fold and crumple the web against the barrier, severing the resulting folded and crumpled mass from the continuous web Upstream of said mass and stuffing said severed mass into a pillow ticking.

By the use of the process of this invention highly resilient pillows are produced at extremely rapid rates at very low cost, using comparatively inexpensve equipment. For example, from a single strand of tow it is possible to produce easily six or more pillows per minute.

The pillows so produced from the lightweight webs are superior to those made by filling the pillow with battings formed from polyethylene terephthalate staple fibers. The pillows keep their springiness and plumpness much longer in use and do not tend to felt and shrink either in use or in washing.

The opening and spreading of the two to form the cohesve web is preferably etfected in the manner taught in the previously mentioned application of Watson, Ser. No. 382,263. The tow used is commonly supplied in the form of a band of parallel crimped filaments packed in a compressed bale. The crimps in the individual filaments are in registry so that there are formed ridges and troughs of aligned crimps, running transverse to the direction of the filaments, across the tow. Often the tow has a fine crimp superimposed on a coarse crimp of much larger amplitude; for example a crimp of 12 crimps per inch superimposed on a crimp of much larger amplitude and of a frequency of about 3 crimps per inch. The crimping is conveniently etfected by the producer in a stuffer crimping zone of the usual type. If a particularly sharp crimp is desired, the tow may be heated during crimping (eg. by means of steam in contact with the tow in the crimping zone).

The tow may be conveniently opened, to prepare it for the air spreading steps by subjecting it, while moving in a predetermined path, to a difierential grippng action between a plurality of points spaced from one another both longitudinally and transversely of the path, so that certain laterally spaced sections of the tow are positively gripped relative to other laterally spaced sections of the tow, alternating with the said gripped sections, which are not gripped at all or are gripped at different relative points. In this manner there is produced, as a function of the differential positive gripping of the tow, a relative shifting of adjacent filaments longtudinally of the tow, whereby the crimps are moved out of registry with one another. Preferably, although not necessarily, the differential grippng action is such that a relative lateral displacement between adjacent filaments of the tow is also eflected, so that the combination of two transverse filament movements brings about the complete opening of the tow.

The differential gripping action may be achieved by the provision of at least one pair of rolls, one of which is smooth-surfaced and the other of which is grooved over its entire periphery; if desired there may be a plurality of such pairs of rolls arranged in tandem. On each grooved roll, the grooves and the ridges alternating therewith may extend obliquely or helically in opposte senses from its center to its opposte ends. Thus, when the tow passes between the two rolls of any given pair of one grooved and one smooth-surfaced roll, some of the tow sections are gripped between the peaks of the ridges of the grooved roll and the outer perpheral surface of the opposed smooth-surfaced roll, while other sections of the tow which are at that time located in registry with the spaces between the ridges of the grooved roll are not gripped between the latter and the smooth-surfaced roll. Generally only one roll of each pair is positively driven while the other is yieldably biased toward it and rotates due to the passing of the tow between the rolls.

Merely by way of example, the foregoing tow opening apparatus may be of the type disclosed in Canadian Pat. 674,101 (corresponding to a copending U.S. patent application Ser. No. 15 1,900, filed Nov. 13, 1961, in the names of D. T. Dunlap and R. E. St. Pierre and assigned to the same assignee as the instant application). To the extent necessary, therefore, the disclosure of the Canadian patent and Dunlap et al. application are incorporated herein by reference.

In the preferred method of spreading the tow is passed through an air spreader in which the moving tow, in fiattened condition, is confined between parallel walls while streams of air or other suitable gas are directed at the tow across its full width. Advantageously, the air spreading is effected in a plurality of stages in each of which the tow is spread to a greater width than in the preceding stage. For best results the tow in any one stage is isolated from the effect of the following stages as by passing the tow between stages firmly in contact with a surface moving at a controlled rate, e.g. around and between a pair of driven nip-defining rolls.

By air spreading it is possible to spread the tow readily, and very evenly, to great widths to produce webs of extreme fineness, such as webs containing less than about 500, e.g. 100 filaments per inch of width, and in which the average air space per fil is appreciably greater than the diameter of the filaments. The average air space per fil is the average space between the filaments of the. web measured on a line in the plane of the web, perpendicular to the longitudinal direction of the filaments of the web, said space being calculated on the assumption that all the filaments are arranged in a single plane, with no filaments crossing other filaments. It may be calculated simply from a knowledge of the average diameter of the filaments (D the width (w) of the substantially uniform web and the number of filaments (n) in said width, according to the formula: Average Air Space Per Fil=(w-nD --r.

In the preferred forms of the invention, the average air space per fil is a plurality of times (e.g. five ten or more times) as great as the average lament diameter. Such webs may have densities well below one ounce per square yard, e.g. to %i or /2 ounce per square yard.

The air spreaders themselves advantageously have airdelivery slits or other suitable openings in one or both of the parallel walls between which the tow passes, said slits leading from a plenum chamber supplied with air at constant pressure. In one highly eifective Construction there are a series of slits, each running in a direction transverse to the direction of movement of the tow and so arranged that all portions of the tow are subjected to the air streams from said slits. Surprisingly it has been found that even when the width of the air spreader is 8 feet or more, the tow spreads uniformly and the outer edges of the tow, where the resistance to the air would be expected to be less, attain substantially the same density as the control portions of the tow.

In cross-section the air-delivery slits are preferably tapered, narrowing toward their outlets. The tapering may be symmetrical about an axs perpendicular to the face of the web so that the air is blown straight at said face, or the slits may be inclined so that the air imparts a forward or backward force to the moving tow.

The pressure in the plenum chamber may vary, one suitable range being about 1 to p.s.i.g.; higher pressures may be used, e.g. 100` p.s.i.g. but these. are economically wasteful. The pressure in the tow-confining zone, between the parallel walls, is believed to be a little less than atmospheric. When the air is blown straight at the face of the web, the air generally leaves the tow-confining zone from both ends of said zone. Surprisingly little air is needed to expand the tow. Despite the fineness of the webs, the walls of the tow-confining zones of the air spreaders need not 'be correspondingly close together; thus very good results have been obtained with towconfining slots inch in width.

In the early stages of spreading the tow web shows striations; that is, there are alternating narrow zones of high fiber density (in terms of the number of filaments per unit of web width) and low fiber density (i.e. visible lean portions) running generally lengthwse of the tow web, but at a slight angle (e.g. 2) to the precise lengthwise direction. The number of such striations corresponds to the number of lands and grooves on the threaded roll engaged by the tow. I have found that an additional stage or stages of air spreading, instead of accentuating these striations, elimnates them to a large extent, and that the striations may be removed by permitting the lightweight web to relax, after leaving the last stage of spreading, The web is generally under a slight tension during its passage through the air spreaders, such tension being insufiicient to remove the crimp in the filaments; on relaxation, the crimp in the filaments increases but the width of the web remains the same. The relaxed webs are quite unform, but often do have some areas of visibly varying fiber density; the uniformity of the latter products is, however,

very much greater than that of the commercially uniform card webs of staple fibers produced on the most modern carding equipment.

In the fine webs of this invention all the. continuous filaments run in the same general direction, lengthwise of the web. However, when one does not look at the whole of the long length of any particular filament, but looks instead at the individual crimps thereof, it will be seen that most portions of the filament do not run in this general lengthwise direction but instead zigzag back and forth across such general direction. The amplitude of the crimps is such that, for any particular filament, the portion of the crimp at one side (hereafter termed the crest of the crimp) overlaps one or more neighboring filaments while the portion of the crimp at the other side (hereafter termed the "Valley" of the crimp) overlaps one or more of its neighboring filaments on said other side. This overlap helps to give the webs their cohesiveness. For example, the filaments in the web may have a crimp whose amplitude (from a median line running in the same direction as the filament) is in the range of about to %e inch, said amplitude being measured from said median line to the top of a crest, or to the bottom of a Valley. Since there may, for example, be several hundred filaments per inch of web width and since the crimps are not in registry there will be considerable overlapping of filaments in the web.

When one turns from an examination of the crimps and takes a somewhat larger, though still relatively short, View of the portion of any particular lament which contains several crimps, and which may be for example /2 inch to several inches long, it will be found that these portions are not perfectly parallel to the longitudinal direction of the web, but make small angles therewith, which angles change in direction and magnitude along the length of the filament; generally these angles are less than 20, although for very short portions (e.g. /2 inch long) the angle may be larger at times.

It is believed that the overlapping of the crimps and the overlapping due to the presence of the angularly disposed short portions, just described, contribute to the cohesiveness of the web so that, despite its fineness, it can be readily handled as a unitary structure. The degree to which the individual filaments meander by virtue of the presence of said crimps and angularly disposed short portions is not, however, very great; typically, the ratio of the straightened lengths of the individual filaments to the lengths of the same laments in the web is less than about 1 /2 :1 and, preferably, greater than 1.1:1, e g. about 1.2:1 to 1.4:1. This ratio may be measured by cutting a predetermined length of the web, removing the individual laments of the cut portion and measuring their lengths while under a tension just sufficient to remove the crimp; the results are then expressed as the ratio between the measured lengths of the individual laments and said predetermined cut length.

In specifying denier per filament and total denier, the number given herein, with respect to tows and webs, is the denier for the laments prior to crimping, i.e. the weight of 9000 meters of straight laments; the weight of 9000 meters of crimped, unstraightened laments or tow will naturally be greater than these values.

Advantageously, the webs are spread to such an eXtent that when further air spreading is attempted, while the length of the web is kept constant, the web strongly resists such spreading and returns to its previous width. That is, if a graph is plotted relating the air pressure in the spreader, as ordinate, to the degree of lateral spreading of the moving web, it is found that there is substantially no additional pressure needed to effect spreading up to a certain width, after which the air pressure required rises sharply. The web density at which this sharp change occurs is termed herein the Potential Web Density. This Potential Web Density will vary depending on the type of tow which is employed and particularly on the degree of intermingling and crossing over of the tow laments. In general, the optimum tows have Potential Web Densities below about 1 ounce per square yard, preferably less than about /2 ounch per square yard. Surprisingly, webs of such densities have been found to be easily handled and to maintain their unity without disintegration or splitting during ordinary handling, folding, etc.

In the work on this invention, it has been found that when battings are made of successve layers of spread webs, the battings made from those webs whose actual web densities are below about 1 ounce per square yard have superior strength and may be handled much more readily without danger of shifting of the layers than battings of the same total weight made from webs of greater densities. In addition, per unit of weight, the battings composed of the low density webs are thicker and more resilient than battings made up of webs of higher density. In general, it is most desirable to use a web whose actual density is less than preferably less than 7 times the Potential Web Density. As will be seen from the examples, however, excellent pillows may be made using webs of higher densities. Incidentally, the battings made by depositing successive layers of the lightweight webs are very much more coherent than battings made by similarly lapping card webs of staple fibers. In the drawings:

FIG. l is a schematic view of a tow-opening and spreading process;

FIG. 2 is a cross-sectional View of an air spreader;

FIG. 3 is a view showing the arrangement of the openings of the air spreader;

FIG. 4 is another view showing the overall arrangement of the slits of the air spreader;

FIG. 5 is a view similar to FIG. 4, but showing an alternative arrangement of the slits;

FIG. 6 is a schematic view showing a process for the production of pillows; and

FIGS. 7, 8 and 9 are schematic views of other, preferred processes for the manufacture of pillows,

FIG. 10 is a side View of a device for measuring the electrical resistance of fibers.

The following examples illustrate the invention further.

EXAMPLE 1 The apparatus shown in FIG. 1 is used to open and spread a band of crimped polyethylene terephthalate tow having a total denier of 128,000 and made up of 5 denier continuous laments, said laments having 12 crimps per inch and a "percent crimp of about 60%. Percent crimp as used herein is where Lc is the length of any predetermined portion of a tow or web and Ls is the average length of the laments of said predetermined portion when under a tension just suflicient to remove the crimp.

The tow band 1 is drawn from the bale 2 through a banding jet 3 comprising a cylinder 4, having a slit running lengthwise of the cylinder at its highest point, and a curved baffle member 6 parallel to, and spaced f inch from, the adjacent surface of said cylinder, so that the tow band 1 passes between said baffle member 6 and said cylinder 4. Air under pressure of 3 p.s.i.g. is supplied to the interior of the cylinder 4 and emerges as a stream from the slit of said cylinder, the slit being cut at an angle such that the air stream has a Component in a direction opposing the forward motion of the stream, there being an angle of about 30 between the stream emerging from the slit and a plane tangent to the cylinder at the point of emergence. The tow band 1, now about 8 inches wide, passes around stationary tensioning bars 7, 8 to help smooth and uniformly pretension said band, said bars being adjustably mounted, so that their angle to the horizontal may be varied, to adjust the position of the band on the equipment, such as rolls, with which the band comes into contact downstream of said bars. After leaving the bars 7, 8, the band passes into the nip between a pair of rubber-surfaced rolls 9, 11 driven at a peripheral speed of 60 feet per minute and then passes horizontally to the nip between a rubber-surfaced roll 12 and a threaded steel roll 13, driven at a peripheral speed of 102 feet per minute, said threaded roll having helical threads of 14 turns per inch cut about inch deep into its outer surface. The tow entering the nip between rolls 12, 13 is still about 8 inches wide. From these rolls it passes still in the same horizontal plane to an air spreader 14 (see also FIGS. 2 and 3) having a tow-receving slot 16 which is 24 inches wide and 4 inches long. The tow-receiving slot 16 is defined by an upper wall 17 and a lower wall 18 spaced inch apart. Below the lower wall 18 is a plenum chamber 19 supplied with air under a constant pressure of 3 p.s.i.g. from a suitable source (not shown) and communicating with the tow-receving slot 16 through air slits 21, each 0.007 inch wide at their outlet ends and tapered to said outlets at an included angle of 45, said slits being each 5 inches long and so arranged (as shown in FIGS. 3 and 4) that the end of one slit is aligned, in the direction of movement of the tow, with the end of the adjacent slit, so that the air is supplied to the tow band across the full 24-inch width of the slot 15. The slits are arranged at small angles (e.g. about 5) to the line perpendicular to the direction of movement of the tow with the slits on opposite sides of the median line of the spreader being mirror images, as shown in FIG. 4; it is found that when the slits are all parallel, and at an angle to said perpendicular line, there is a tendency for the tow band to be turned from its straight path by the action of the air, the band at one side of said median line being retarded and at the other side being accelerated. Instead of angularly arranged slits there may also be employed slits 21a (FIG. 5) running perpendicular to the direction of movement ot' the tow and in parallel rows, spaced with the end of a slit in one row aligned, in said direction of movement, with the end of a slit in the adjacent row so that the air is supplied to the tow band across the full 24-inch width of the slot 16, without any substantial operative overlap of the slits.

The tow band diverges uniformly from its 8 inch width at rolls 12, 13 to the full 24-inch width at the exit of spreader 14, the entrance of which is located one foot from the nip of rolls 12, 13. The tow is pnlled through the spreader 14 by the action of a pair of rolls 26, 27, making an S-wrap around these rolls; that is, passing 180 around rubber-surfaced roll 26 then passing through the nip between the rolls and then making another l80 wrap around a steel-surfaced roll 27. The tow web keeps its 24-inch width during its travel to and around the rolls 26, 27 which are driven at a peripheral speed of 61 feet per minute.

From the lower portion of roll 27 the tow then passes to the entrance of air spreader 28 which is located 3 feet horizontally from, and about one foot below, the level of the bottom of roll 27, so that the tow makes a smooth curve which is horizontal at the entrance of spreader 28. The spreader 28 is of the same design as spreader 14, except that its tow-receiving slot is 50 inches wide, and it is operated under the same air pressure as spreader 14. The tow web spreads uniformly in its horizontal passage to spreader 28, at which it reaches its SO-inch width and then maintains the same width during its passage to a pair of rolls 29, 31, driven at a peripheral speed of 59 feet per minute, which serve to pull the web through the spreader 28. Roll 29 is rubber-surfaced while roll 31 is steel-surfaced; the top of roll 29 is on a level with the tow-receiving slot of spreader 28 and below the bottom of roll 27. The tow makes an S-wrap about the rolls 29, 31, falling from the roll 31 in a freely hanging shallow catenary 32 onto the horizontal moving surface of a wide endless belt 33 driven at a speed of 55 feet per minute. An idler roll 34, mounted on lever arms 36 pivoted at 37, extends across the full width of the tow web on belt 33; this idler roll serves to bring the tow web into firm contact with the belt 33, to define the shape and position of the catenary 32, and also to keep any loose ends in the catenary portion from being drawn around the roll 31. The path of the belt is 2 feet below the bottom of roll 31 and the roll 34 is mounted inches forward (in the direction of movement of the belt) of the center of roll 31. The web on belt 33 has a width of 50 inches and a weight of 14 grams per square yard, and its percent crimp is about In this example, the upper roll of each of the pairs of rolls is pressed downwardly, by any suitable loading device, and is driven by frictional contact with the tow on the lower roll of the pair, which lower roll is rotated by any suitable driving means (not shown).

A barrier 38 (FIG. 6) is placed just above belt 33, with the bottom of the barrier slidably resting on the belt. The lightweight web 39 travelling with the belt piles up in a loosely folded and crumpled mass against the barrier 38 which may, for example, be 10 inches high. When the desired amount of web (e.g. 1% lbs.) has piled up against the barrier, the Web is cut transversely upstream of the folded and crumpled mass as with a knife 40, and the mass of folded and crumpled web is pushed or pulled transversely off the belt 33 as by pusher 41 into a suitable hollow form or mold 42 and into a sacklike pillow ticking 43 whose mouth is aligned with the outlet of said mold 42. When the freshly cut end of the web travelling with the belt 33 reaches the barrier, a new pile-up is begun and the action is repeated. The whole operation may readily be made automatic, since the web is supplied at a uniform controlled speed and at a uniform weight per unit of time. Thus, in one form of apparatus, the operation of the knife and the pusher 41 are controlled by a suitable timed controller to operate substantially simultaneously at predetermined intervals, so that when a preset weight of the web has folded against the barrier the knife 40 is actuated to cut the web and the pusher is actuated to transfer the accumulated web to the mold 42. In this way highly resilient pillows may be produced continually at a very high rate from suitable stiff, resilient filaments, such as filaments of terephthalate esters.

In another method, the barrier 38 is adapated to be raised when the desired weight of crumpled web has accumulated and the web has been severed, as previously 8 described. The accumulated mass then is carried by the belt 33 to a pillow packing station (not shown) located at the turning point of said belt. The barrier is quickly lowered after the mass of crumpled web has passed under it, so as to begin a new cycle.

EXAMPLE 2 (a) When the speeds of all rolls and of the belt are increased to about 6 times the values given in Example 1 above (so that the speed of the rolls 29, 31 is yards per minute) substantially the same product is obtained. Surprisingly, despite the great increase the rate at which the web is produced, the total volume of air used and all other conditions, are substantially unchanged.

(b) On increasing the speeds of the rolls and the belt to about 10 times the values given in Example 1 above (so that the speed of rolls 29, 31 is 200 yards per minute) substantially the same product is obtained, and as in Example 2(a) above, the total volume of air consumed and all other conditions remain substantially the same despite the tenfold increase in producti vity.

EXAMPLE 3 This example llustrates the use of an apparatus which facilitates the handling of the crumpled mass during the cutting and stuffing Operations, while the web is fed to the crumpling and folding zone at a high speed. As shown in FIG. 7, the opening and spreading stops are the same as those of Example l except that the tow, after leaving the roll 31, passes between a driven roll 51 and an idler roll 52 and drops onto (and is permitted to relax on) a barrier 53 which, in the embodiment shown in the drawing, is made up of a pair of doors 54, 56 pivoted at their upper ends 57, 58 on parallel horizontal pivots 59, 61, respectively. The doors are maintained in closed position, with their edges in contact, in any suitable manner as by means of hydraulic operators 62, 63 which may also be actuated to move the doors to open position. When the desired amount of spread tow has accumulated on the barrier 53, the doors are opened for a very short interval and the folded and crumpled mass is allowed to drop onto a slowly moving endless belt 64 (moving at a speed of, for example, about 50 to 60 feet per minute). The doors are then closed again and the tail of tow extending up from the crumpled mass is cut, as by the filamentfusing action of an electrically heated wire 66 moving across this upwardly extending tail. The wire 66 may be mounted, as shown, on one of the doors 56 for movement with that door or may be separately mounted and actuated either independently or by movement of the door. The door actuators may be controlled by a valve 67 actuated by any suitable intermittently Operating mechanism 68, preferably one which is responsive to the amount of tow deposited ou the barrier 53; thus the mechanism may be directly responsive to the weight of tow accumulated on the barrier, or it may be operati'vely connected to one of the feed rolls 51, 52 so that it operates when a given length of tow, as measured by the number of revolutions of these rolls, has been supplied to the barrier, or it may be connected to a suitable timer. The individual masses of tow deposited on the slowly moving belt may be deposited in a collection trough 70 and manually or automatically stuffed into a pillow ticking, as in the manner shown in FIG. 6.

It will be seen that, in contrast to Example 1, the stuffing and cutting Operations of Example 3 are carried out on a material which is not moving rapidly, and that the tow may be spread and delivered to the barrier at very high rates (such as speeds of about 300 to 600 f.p.m.) without increasing the difficulty of the cutting and stufiing Operations.

Another method of achieving an effect similar to that shown in FIG. 7 is illustrated in FIG. 8 in which the doors 54, 56 are kept open while the major portion of the web making up the pillow filling passes, through the open doors, onto the slowly moving belt 64 where, because the speed of the belt is less than that of the web, the Web forms a crinkled, flufy layer on the belt. In this embodiment, a movable barrier 71, like barrier 38, is placed across the belt 64 with the bottom of the barrier 71 slidably resting on the belt, so that the web, travelling with the belt as a flulfy layer, piles up in a loosely folded and crumpled mass against the barrier. As in the embodiment shown in FIG. 7, the width of belt 64 is at least equal to the width of the web falling from the rolls 51, 52 so that the Web is uniformly deposited across the width of the belt; this is not essential, however, since for example suitable guides for decreasing the width of the web before it engages the belt may be provided. When the desired amount of web material has piled up against the barrier 71, the doors 54, 56 are closed so that the web is cut transversely by the action of the heated wire 66. The barrier 71 is then raised momentarily, permitting the crumpled mass to move With the belt 64 to a suitable pillow-stuffing station, and the doors 54, 56 are opened, permitting 'the small mass of web material accumulated on the doors to fall onto the belt 64 and pile up, with the subsequently delivered web, on the barrier 71, in the next identical cycle of operation. In the modification shown in FIG. 8, less headroom is required than is needed for that of FIG. 7, since space need not be provided for a large fluffy mass of crumpled web material above the doors.

Another arrangement, shown in FIG. 9, is similar to that of FIG. 8. Here the positions of the feed rolls (51 and 52 in FIG. 8) are changed, so that the web now makes greater contact with the feed rolls, numbered 81 and 82 in FIG. 9; this gives better control of the web feed rate. When the distance between the feed rolls and the doors 57, 58 is relatively short (e.g. 4-5 feet or less), the weight of the short length of the moving web hanging from the feed rolls is sometimes insuicient to keep the filmy web from drifting sideward against one of the feed rolls, starting an undesired roll wrap. To prevent this, an air control device, comprising parallel tubes 83, 84, one on each side of the web, is placed below the feed rolls. Air under low pressure is supplied to the tubes 83, 84, which have spaced perforations, facing the tow band, arranged to direct gentle streams of air downwardly toward the web (eg. at an angle of 45 to the horizontal) along the whole width of the web.

The steps of crumpling and of stuffing the crumpled mass into a pillow ticking may be performed substantially simultaneously, as by feeding the spread tow directly into the ticking. Thus the spread tow web may be passed down into a guide tube, e.g. a tube of downwardly tapering conical shape in which the moving tow folds longitudinally, and then into the ticking. Here the tow may be crumpled against the bottom of the ticking, which serves as the barrier, or an intermediate intermittently movable barrier may be placed just above the ticking.

In the practice of this invention, high speed operation is facilitated by omittng devices that produce regular folds. The folded and crumpled mass so produced has a random configuration. In this mass the lengths of spread tow between folds may, for example, be in the range of about l to 4 inches.

In the finished pillows, the Weight of crumpled web material Will depend, of course, on the desired resilience and size of the pillow. For pillows of the conventional sizes (having an area of about 500 to 600 square inches, e.g. a pillow whose dimensions are about 20" by 26") the density of the crumpled web is advantageously in the range of about /2 to 1 /2 pounds per cubic foot before stuffing into tick.

According to another aspect of this invention, it has now been found that outstanding results are obtained by using filaments carrying a hydrophobic silicone finish containing little or no antistatic agent, as described in my copendng application Ser. No. 382,018 filed July 13,

1964, whose entire disclosure is hereby incorporated by reference. Not only does the use of such a finish enhance the spreading action in the production of the continuous light cohesive webs, but it results in the production of pillows of especially good resiliency. The filaments carrying the silicone finish containing little or no antistatic agent (eg. at most about 0.1% weight percent, preferably less than 0.05%, of antistatic agent based on the weight of the fiber) have very slick surfaces and there is very little friction between filament surfaces, so that the filaments can slide past each other freely. Thus there is little, if any, frictional interference with the inherent resilient recovery properties of the individual filaments. The pillows stufied with the filaments are also easily washed, and dry rapidly to return to their original highly resilient condition. In conventional polyester staple fiber filled pillows the staple fibers carry a considerable proportion of a relatively tacky antistatic agent which increases the fiber-to-fiber friction and, I have found, decreases the resiliency of the pillow. The presence of anti static agent is, however, essential when the staple fibers are employed in order that these fibers may be handled readily in the usual preparatory Operations, eg. picking and carding. It will thus be seen that, in accordance With this aspect of the invention, an inherently high static fiber, such as polyethylene terephthalate, which ordinarily must be given an antistatic finish to permit it to be handled, is here given a finish which, in contrast, increases the static properties of the fiber.

The electrostatic properties of the fiber may be expressed in terms of the electrical resistance of the fiber. The high static fibers of this invention preferably have resistances, measured in the manner described below, of at least 12 logohms, preferably at least 14 logohms and most preferably at least 15 logohms. A typical siliconecoated polyethylene terephthalate fiber highly suitable for the practice of this invention has a resistance of 15.3 logohms; as used herein the electrical resistance of the fiber is the value measured by the following method: A 1.7 gram specimen of tow l0 inches long is placed on a sample holder illustrated in FIG. 10 composed of a series of 5 horizontal knife-edged bars 91, supported parallel to each other along a circular arc between insulated holders so that each knife edge is 1.3 inches from its neighboring edge. The specimen 92 is draped over these bars in contact with the knife edges, one end of the specimen being held in a fixed clamp 93 and the other end being clamped to a 171 gram weight 94 which is supported only by the specimen. The specimen is clasped in such a fashion that its width, as draped over the bars 91, is one inch. A voltage of volts D.C. is applied successively across each pair of adjacent bars and the current flowing through the tow in response to that voltage is meas ured. The five readings of current are averaged and the average resistance of the tow sections between knife sections is thus determined in accordance with Ohrns law average current) All measurements are made at 70 F. and 40% R.H., with tow that has been preconditioned at 70 F. and 40% R.H. for 24 hours.

Preferably there is a tough, fiexible, hydrophobic film of silicone resin around each individual fiber. The silicone is desirably applied to the filaments during their early stages of processing and before the band of tow is crimped. This may be done Conveniently by passing the filaments through an aqueous emulsion of a relatively low molecular weight curable liquid silicone prior to the step of crimping the filaments and, in the case of materials which, like polyethylene terephthalate, must be drawn to develop desirable tenacity and resistance to elongation, prior to the drawing operation.

A suitable silicone is readily made, for example, from the hydrolysis of a major portion of an alkyl dichlorohydrogen silane and a minor portion of a dialkyl dichlorsilane. If desired, there may also be incorporated a small amount of trialkyl chlorosilane (as a chain terminator) and a small amount of alkyltrichlorosilane (to promote prcliminary cross-linking). All the alkyl groups are preferably methyl groups. The use of these starting reactants results in a relatively fluid silicone containing a major portion of methylhydrogenpolysiloxane and a minor portion of dimethylpolysiloxane.

The polymeric silicone, after it has been emulsified and the emulsion applied to a filamentary material, can then be catalytically oxidized or cured so that the silane hydrogens are converted to additional siloxane oxygen bridges, to further cross-link the silicone. The resultant cross-linked polymeric product is tough, hydrophobic, and highly lubricating; forming a flexible film around the surface of each filament.

It is convenient to first emulsify the silicone so as to form an aqueous emulsion of paste-like consistency. Any of the conventional silicone emulsifying agents, e.g. trirnethylnonyl ether, can be used. The average particle size of the silicone polymer in this paste emulsion is generally from about 1 to 8 microns, and typically is about 5 microns. This paste is then incorporated into the finishing bath, along with Catalyst. The Catalyst compound used to promote further cross-linking of the silicone is of the conventional type used for silicone curing and generally is an organometallo compound or mixture thereof, and is typically an organometallo salt. Generally the metal portion of such Catalyst compound is zinc, tin, aluminum,

zirconium, or the like. Suitable catalysts include Zinc acetate, aluminum octoate, Organic titanates, and mixtures thereof. As stated previously, such Catalyst promotes oxidation of the silane hydrogens to produce additional siloxane oxygen linkages and thereby promote further t cross-linking of the silicone polymer.

Generally the catalyst is maintained separate from the silicone emulsion until the finishing bath is to be prepared, and desirably is added as the last Component to the finishing bath.

Desirably the weight ratio of silicone to metal Catalyst is from about 8 to 1 to about 1 to 1. A more preferred range is from about 5 to 1 to about 3 to 1. The aqueous composition applied to the filaments may contain, for example, 1 to 5% of the silicone.

The proportion of silicone on the filaments is advantageously less than 1%, preferably in the range of about 0.2 to 05%, based on the Weight of the filaments. The amount of any antistatic agent present should be less than /3, preferably less than /5 the weight of the silicone.

The crimping of the filaments carrying the silicone finish is advantageously carried out in a stuffer crimper, which may be of the standard stufiing box type in which the tow is forced into a narrow confined zone, thus folding the filaments back and forth on themselves in their passage through said zone. The tow in the crimper may carry a wet film of the aqueous uncured silicone finishing composition, which may be subsequently cured by heat treatment of the crimped tow while the latter is maintained in a relaxed condition, e.g. at a temperature above 100 C., for example, 130-180 C. Curing of the silicone may also be effected prior to crimping, as by passing the filaments carrying the uncured silicone 'finish through a heated drawing zone.

The invention finds its greatest utility in the production of pillows from tows whose filaments are of polyethylene terephthalate. It will be understood that it is within the broad scope of the invention to carry it out with other tows, such as those made of other polyesters (eg. the polyesters of terephthalic acid and other glycols such as dimethylol cyclohexane), luear superpolyamides (such as nylon 6 or nylon 6,6), polyacrylonitrile and copolymers of acrylonitrile, olefinic polymers and copolymers, e.g. isotactie polypropylene, secondary cellulose acetate (of the usual acetyl content, eng. about 54-55% calculated as acetic acid), other Organic derivatives of cellulose such as esters and/or ethers of cellulose, for example cellulose propionate and cellulose acetate propionate or the like, highly esterified cellulose containing less than 0.29 free hydroxyl groups per anhydroglucose unit such as cellulose triacetate, rayon (regenerated cellulose). The number of 'filaments of the starting tow can vary within wide limits and may range up to as high as 1,000,000, with a denier per filament as high as 25, e.g. 1 to 20. The number of crimps per inch of tow may range up to as high as about 80, but for most end products to be described herein about 3 to 50, preferably about 3 to 20, crimps per inch of starting tow are found sufficient.

It is to be understood that the foregoing detailed description is given merely by way of illustration and that many variations may be made therein without departing from the spirit of this invention.

T he embodiments of the invention in which an ex clusive property or privilege is claimed are defined as follows:

1. A pillow filled with a cohesive web of deregistered crimped continuous substantially parallel filaments carrying a coating consisting essentially of a hydrophobic silicone, said coated filaments having an electrical resistance of at least 12 logohms.

2. A pillow as set forth in claim 1 in .which said filaments are of terephthalate polyester and the crimps of the 'filaments of the web overlap adjacent filaments of the web on both sides of said filaments.

3. A pillow as set forth in claim 1 in which said web is randomly crumpled, said filaments are of terephthalate polyester and said electrical resistance is at least 15 logohms.

4. A pillow as set forth in claim 1 in which said filaments have a crimp amplitude of from about inch to 7 inch and a ratio of the straightened lengths of individual filaments to the lengths of the same filaments in the web of from about 1.1:1 to 1.521.

5. A pillow as set forth in claim 2 in which said filaments are of polyethylene terephthalate of a denier of about 1 /2 to 10, and said web is one which, before crumpling, has a weight of at most about 2 ounces per yard, a width of at least about 24 inches and contains at least about 50,000 filaments, the density of crumpled web in said pillow being about /2 to 1 /2 pounds per cubic foot.

6. A pillow as set forth in claim 4 in which the ratio of the straightened lengths of individual filaments to the lengths of the same filaments in the web is from about 1.2:1to1.4:1.

References Cited UNITED STATES PATENTS 3,251,794 5/1966 Paliyenko 5-337X 3,071,783 1/1963 Gamble i 5-337 3,156,016 11/1964 Dunlap et al. 19-66 BOBBY R. GAY, Primary Examiner A. M. CALVERT, Assistant Examiner U.S. Cl. X.R. 5-345; 19-66

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