US 3505155 A
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April 7, 1970 R. H. BALCH ET AL 3,505,155
NONWOVEN CONTINUOUS FILAMENT PRODUCT AND METHOD OF PREPARATION Filed Aug. 7, 1967 3 Sheets-Sheet 1 FIG 3 INVENTOR RALPH H. BALCH GEORGE A. WATSON HERBERT W COATES April 7, 1970 H. BALCH ET AL 3,505,155
NONWOVEN CONTINUOUS FILAMENT PRODUCT AND METHOD OF PREPARATION Filed Aug. 7, 1967 3 Sheets-Sheet 2 H G 8 INVENTOR RALPH HBALCH GEORGE A. WATSON HERBERT W COATES A'ITO NEY April 7, 1970 R. H. BALCH ET AL 3,505,155
NONWOVEN CONTINUOUS FILAMENT PRODUCT AND METHOD OF PREPARATION Filed Aug. 7, 1967 3 Sheets-Sheet 3 FIG 9 FIG IO FIG l2 INVENTOR RALPH H BALCH GEORGE A. WATSON HERBERT W. COATES Ww QZM ATIOR EY United Patent 3,505,155 Patented Apr. 7, 1970 3,505,155 NONWOVEN CONTINUOUS FILAMENT PRODUCT AND METHOD OF PREPARATION Ralph H. Balch, Charlotte, George A. Watson, Davidson, and Herbert W. Coates, Charlotte, N.C., assignors to Celanese Corporation, New York, N.Y., a corporation of Delaware Continuation-impart of applications Ser. No. 325,254, Nov. 21, 1963, and Ser. No. 501,105, Oct. 22, 1965. This application Aug. 7, 1967, Ser. No. 658,781
Int. Cl. B32b 5/12, 7/08, 31/08 US. Cl. 161-57 29 Claims ABSTRACT OF THE DISCLOSURE Background of the invention This is a continuation-in-part of Ser. No. 325,254 filed Nov. 21, 1963 and Ser. No. 501,105 filed Oct. 22, 1965, both now abandoned.
This invention relates to continuous filament nonwoven products and more particularly to products produced by dimensionally stabilizing a spread web of continuous filament deregistered crimped tow.
Nonwoven fibrous products are well known in the art. Normally, such products are made from staple fibers but more recently, methods have been devised for producing various products from continuous filaments. As is well known, staple fiber nonwovens by their vary nature, are not possessed of any considerable inherent tensile strength in any direction and thus are ordinarily easily distorted and even destroyed unless specially reinforced. Even when reinforced, it has been found that staple fiber nonwovens do not have the desired degree of stability and durability, because they not only tend to lose fibers through migration, but they are also inadequate in the ability to retain bulk, compressibility, resilency and the like.
To avoid some of these drawbacks and disadvantages, it has previously been proposed to utilize continuous filaments. Various methods have been devised to produce nonwoven sheet materials composed of continuous filaments. While such processes have various advantages for particular uses, certain disadvantages also accompany many of these processes. Particularly, most of such continuous filament processes are limited to production by the filament manufacture and the resulting product cannot be readily changed subsequently by the manufacture of the finished product if somewhat different physical characteristics of the fabric or sheet material are desired. Also, many of these processes rely upon melt adhesion of the fibers to bond each other while still in a relatively plastic condition. This type of bonding greatly limits certain bulk characteristics often desired in the end product.
- It is an object of the present invention to provide a dimensionally stabilized, nonwoven, deregistered, crimped, continuous filament product particularly suitable for a wide variety of end uses, particularly bulky products of an insulating and/or cushioning character. It is another object of the present invention to provide a method for producing such products. These and other objects will become apparent to those skilled in the art from a description of the invention which follows:
Summary of the invention In accordance with the invention a nonwoven continuous filament product is produced comprising deregistering a tow of crimped continuous filament, spreading the deregistered tow to produce a web and subsequently dimensionally stabilizing the web to produce the nonwoven continuous filament product. Dimensional stability is preferably achieved by bonding and/ or stitching and/ or laminating the spread web to a sheet material.
The present invention is particularly suitable for the production of insulating material and cushioning material as well as fibrous sheet material suitable for clothing, synthetic paper, pillows, carpets, carpet underlay pads, mattress pads, quilts, and the like. When attaching a spread web to a dimensionally stable sheet such as a woven fabric such as by stitching, unexpectedly full and bulky products are obtained by securing the fibrous web to the sheet material while holding the fibrous web under tension. The resiliency and bulkiness of the fibrous web creates a putty, full product when the tension is released,
due to the tendency of the spread Web to return to its original longitudinal length. Thus, extremely bulky insulating products such as insulating clothing, mattress pads, sleeping bags, pillows :and the like, cushioning and insulating materials are produced With greatly improved bulky properties. Further, these characteristics are permanently retained in the end product even after extensive usage and washings.
Brief description of the drawings The invention will be more fully described by reference to the drawings in which:
FIG. 1 is a schematic illustrating a method of deregistering a continuous filament tow and subsequently spreading the tow into a web;
FIGS. 2 and 3 are schematic illustrations of methods and apparatuses for applying a bonding agent to the spread tow or web;
FIG. 4 is a schematic illustration of a method for producing a pleated or corrugated web from spread tow to which a bonding agent has been applied;
FIG. 5 is a plan view of a section spread tow to which a bonding agent has been applied in the form of discrete dots or small areas;
FIG. 6 is a schematic illustrating a method which may be employed to folding and/or linearly lay or cross lay a spread tow to produce a web of increased thickness;
FIG. 7 is a schematic illustrating a method which may be employed to laminate a web of spread tow onto one or more additional webs or sheet material;
FIG. 8 is a schematic illustrating a method for dimensionally stabilizing a web by stitching the web or plurality of webs to themselves or stitching the web to a sheet material;
FIG. 9 is a view along line 9-9 of FIG. 8, further illustrating the web stitching method and showing a pretensioning device through which the spread tow is passed prior to the stitching operation;
FIG. 10 is a schematic illustrating another method for laminating one or more webs of spread tow' to each other or to a sheet material;
FIG. 11 is a schematic illustrating another method for making a bulky material by attaching a pleated or corrugated web between two sheet materials; and
FIG. 12 is an enlarged partial, sectional view of a composite fabric body produced by the method of FIG. 11.
3 DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring more particularly to FIG. 1, a band of crimped continuous filament tow is drawn from a bale 12 through a banding jet 13. Banding jet 13 preconditions the tow for further processing by removing snags, false twists and the like and straightens and flattens the tow so that it may be more readily processed. From banding jet 13, the tow is passed around stationary tensioning bars 17 and 18 prior to passing into the tow opening zone.
The tow is conveniently opened or deregistered to prepare it for one or more spreading stages, by subjecting it, while moving in a predetermined path, to a differential gripping action between the plurality of points spaced from one another both longitudinally and transversely in 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 grip sections are sections where the tow is not gripped at all or it is gripped at different relative points. In this manner there is produced a relative shifting of the adjacent filaments longitudinally along the tow whereby the crimps are moved out of registry with one another. The shifting action is a function of the differential positive gripping of the tow. Preferably, although not necessarily, the differential gripping action is such that a relative lateral displacement between adjacent filaments of the tow is also effected, so that the combination of two transverse filament movements brings about the complete opening of the tow.
Several methods for effecting the differential gripping action are known in the art as well as several different apparatuses for effecting differential gripping, which apparatus deregister the tow with varying degrees of success. A preferred apparatus and method is disclosed by Dunlap et al., in US. Letters Patent 3,156,016.
Typically, the differential gripping is achieved by using at least one pair of rollers, one of which is smooth surfaced and the other of which is patterned over its entire periphery. The most preferred apparatus comprises a plurality of such pair of rollers arranged in tandem wherein one of each pair of rollers comprises a smooth surfaced roll coated with a resilient material such as rubber, and the other roller has alternating lands and grooves. Preferably, the lands and grooves form helical threads of about 8 to 20 threads per inch.
It will be apparent that the opening of the tow for the purposes of the present invention may be effected by means differing from the threaded roll type of apparatus disclosed in the aforesaid Dunlap et al. patent, although this tow opening and crimp deregistering apparatus is preferred due to its high efficiency and its uniformity of operation. For example, the grooves on the roll need not be helical but could have other configurations such as circular rings. If desired, the grooves may be discontinuous i.e. take the form of intermittent depressions in the surface of the roll, and may, for example, impart to the roll surface a checkerboard or other pattern of alternately raised and depressed areas. Both rolls of any one set could be grooved, if desired, although best results are achieved when but one roll is so grooved. The path of the tow in moving between the nips of successive roll sets is horizontal in the Dunlap et al. disclosure but can be made vertical if desired.
Thus, the tow is passed through the nip of a pair of rollers 19 and 21 prior to being passed through a second pair of rolls 22 and 23. In the most preferred embodiment, rolls 19 and 23 are patterned rolls such as threaded steel rolls and rolls 21 and 22 are resilient surfaced rolls.
Each pair of rolls is individually driven at a predetermined controlled speed. Generally, only one roll of each pair is positively driven while the other is in yieldable compressive contact with the driven roll and rotates due to the passing of the tow between the rollers. The differential gripping and deregistering action is produced by driving 4 the second pair of rollers at a faster rate of speed than the first pair. Thus, the second pair of rollers is typically driven at a rate of about 1.1 to about 8 times and more preferably, at a rate of about 1.2 to about 3 times that of the first pair.
On leaving the deregistration zone, the crimp in the tow is out of registry with adjacent filaments.
After deregistering the tow, the tow is subjected to one or more spreading stages. Various spreading means can be used to spread the deregistered tow into a uniform web. Such means include mechanical spreading bars, diverging belts, air jets and the like. The most preferred means is an air jet. Using such spreading means, the tow can be spread into a web of relatively great width ranging up to about 80 inches or more depending on the denier and number of filaments of the tow being spread. Because the most preferred means of spreading is by use of an air jet, the invention will be described more particularly with reference to air spreading although it is to be understood that other types of spreaders can be used.
The tow passing from the deregistration zone is thus passed through a first spreader 24. The tow is pulled through the spreader 24 by the action of driven rollers 36 and 37 about which tow 10 is S wrapped. In passing through spreader 24, the tow is spread about 2 to 4 times the width of the tow exiting from the deregistration zone. As is often preferred in the present invention, the tow is preferably again spread in a second spreader 38 wherein the spread band is again spread to 2 to 4 times the width of the web drawn through rollers 36 and 37. Again the Web is drawn through spreader 38 by means of another set of driven rollers 39 and 41. Thus, the spreading action preferably spreads the tow into a web at least twice the original width of the tow and more preferably at 2 to about 10 times the original tow width to produce a lightweight web of less than about 1 ounce per square yard. More preferably, webs in the weight range of about 0.005 to 0.5 ounce per square yard and most preferably of about 0.01 to about 0.25 ounce per square yard are readily produced.
From rolls 39 and 41, the tow falls in a freely hanging shallow catenary 42 onto a horizontal moving surface of a wide endless belt 43. Idler roll 44 mounted on lever arm 46 pivoted at 47, extends across the full width of the web on belt 43. The idler roll serves to bring the tow web into firm contact with belt 43, to define the shape and position of catenary 42 and also to keep any loose ends in the catenary portion from being drawn around roller 41.
The spread web is then in condition to be dimensionally stabilized to form a more useful end product. As will be readily recognized, the spread web has substantial stability in the longitudinal direction along the direction of the filaments but the stability across the width direction is extremely low. Thus, applying a tensile force longitudinally along the filament length will result in a substantial strength, depending on the fiber used, with substantial recovery to the original length. However, by applying a tensile force across the width of the web, comparatively little resistance will be noted and a relatively low recovery will result. Thus, the web can be readily split in this manner thus losing its integrity as a web.
The present invention is useful with all continuous filament materials which have been crimped prior to deregistration. The process is particularly useful with filaments of polyethylene terephthalate polyester and cellulose acetate of the usual acetyl content of about 54 to 55 percent calculated as acetic acid. However, the invention is also equally applicable to other tows such as those made of other polyesters such as polyesters of 70/30 isophthalic and terepthalic acids and other glycols such as dimethylolcyclohexane; linear super polyamides such as nylon 6 and nylon 66; polyacrylonitrile and copolymers of acrylonitrile; olefinic polymers and copolymers such as isotactic polypropylene; other organic derivatives of cellulose such as esters and/ or ethers of cellulose, for example cellulose propanate and cellulose acetate propanate and the like; highly esterified cellulose containing less than 0.29 free hydroxyl groups per anhydroglucose units such as cellulose triacetate, rayon and the like.
The number of filaments in the starting tow can vary within wide limits and may range up to as high as about one million with a denier per filament as high as about 25, that is, in the range of about 0.5 to about 25 and more preferably in the range of 1 to 20 denier per filament. The number of crimps per inch of tow may range up to as high as about 80, but for most end products a crimp of about 3 to 50 crimps per inch, preferably about 3 to 20 crimps per inch of starting tow are found to be exceptionally satisfactory.
Referring more specifically to FIGS. 2 and 3, the spread web can be unified or dimensionally stabilized without recourse to auxiliary sheet materials. Accordingly, in one aspect of the invention, the spread web is passed through a fibrous bonding applicator device 48 wherein the bonding agent is applied to the spread web. Various means for applying the bonding agent to the web can be utilized including spray applications, dip coating, roller coating and the like which may be designed to apply the bonding agent to either one or both surfaces of the web. Various bonding agents can be used as are well known in the art. The bonding agent may be a plasticiser or solvent for the thermoplastic material of which the filaments are composed, or a suitable adhesive composition which is compatible with the thermoplasti material. The particular bonding agent used can be chosen to give certain characteristics to the end product. For instance, a flexible bonding agent is used when the end product is to be used for soft cushioning material and a rigid type bonding agent is used when such characteristics are desired. For cellulose acetate filaments, for example, a plasticiser such as triethylcitrate, dimethoxyethylphthalate, methylphthalyl, ethylglycolate and glycerol triacetate (triacetin) or a solvent such as acetone may be employed. For polyester filaments various substances such as chloral hydrate and certain synthetic polymer emulsions have been found to be particularly suitable. Emulsion polymers such as polyurethane latexes, melamine formaldehyde resins, but a diene resin and the like are examples of other typical bonding agents.
As will be readily recognized, in order to enable maximum possible production rates, the bonding agent is preferably of a quick setting or quick drying type. Thus, the web upon leaving applicator 48 may be passed through a heater dryer apparatus 49 or the like or it may be passed over an open air framework 50, which is particularly suitable if the bonding agent is of the air drying type, prior to being fed to a take up means 51.
The total amount of bonding agent applied per unit area web can vary widely from about 2 to about 200 percent of the dry base weight of the web and more preferably within the range of about 5 to 100 percent which has been found to be highly preferred for most end uses. It will be recognized that the bonding can take place either with the initial lightweight web or after layering the lightweight web so as to comprise a web having a plurality of lightweight webs laying one on top of the other. Alternatively, the lightweight web can be cross lapped rather than layered prior to the bonding operation.
The base weight of the web or spread tow will depend principally on the initial characteristics of the tow such as the total denier and denier per filament of the starting tow and also on the amount of spreading to form the web. While the spread web is preferably of a weight of less than about 1 ounce per square yard, the web being impregnated may be crosslapped or layered as hereinbefore noted so as to increase the weight of the web to 8, 12,
16 or more ounces per square yard as may be desired for the particular end use.
The bonded filamentary material is advantageously employed as industrial air and liquid filters, fabrics, both with and without calendering, and the like products, of which substantial tensile strengths and the ability to retain the original shape are important characteristics. Alternatively, the bonded web can be further processed as hereinafter described.
When a bulkier base material is desired, one manner of treating the filamentary web is in accordance with FIG. 4. In accordance with this arrangement, the spread web 10 is fed by feed rollers or the like into a stuffer box 52. At the entrance to the stuffer box, the web is acted upon by a reverse folding means such as a pair of alternating, reciprocating bars 53, a star wheel folder (not shown) or the like. The initial plain web is thus transformed into a pleated or corrugated structure 54 which, as it passes through the stuffer box, is compacted until it emerges as a considerably bulkier web 55 which is highly suited for use as batting or padding in a great variety of products. Preferably, the discharge section 56 of stuffer box 52 is heated by heating means. The unbonded filamentary web 10 is thereby stabilized in its pleated form 55 by causing the filaments to set or to become fused to one another at the points of intersection. When the Web is previously passed through a bonding agent applicator device 48 then heater section 56 acts to stabilize the pleated web 55 in the same manner as the heater dryer 49 shown in FIG. 2.
The final stabilized Web is thereafter taken up for storage or immediately further processed as may be desired in the particular end use. Again, it is to be noted that a plurality of individual spread tow in either bonded or unbonded tow bands 10, can be cascaded or fed simultaneously to stuffer box 52 at preselected relative speeds, in order to facilitate the exercise of precise control over the base weight of alternate web 55.
In certain applications, it has been found desirable to apply the bonding agent only in a predetermined fraction or percentage of the total area of Web 10. Thus, the bonding agent can be applied in the form of a plurality of discrete dots or circular areas 57, as shown in FIG. 5, arranged in a plurality of mutually perpendicular rows and columns. Various designs of application can be used including dots or areas in any given row or column being staggered with respect to the dots or area in the next adjacent row or column, with each two adjacent dots or areas of each preferably extending crosswise to the filament orientation overlapping slightly the loci of the lateral boundaries of the dots or areas of the intermediate column extending lengthwise of the filament orientation.
This spot bonding technique provides a novel continuous filament fleece-like fabric possessed of excellent textile properties such as softness or hand, flexibility or drape and three dimensional appearance as noted in high loft characteristics. Because the bonding agent is applied to only a predetermined fraction of the total area of the original web 10, the fabric is rendered dimensionally stable while still being fully flexible in all directions. High softness fleece fabrics of this type are particularly advantageous for the manufacture of a great number of products such as surgical dressings, disposable table napkins, hand towels, diapers and the like, as well as numerous other products.
In addition to the method of increasing bulk illustrated by FIG. 4, the spread web 10 can be folded or lapped in accordance with FIG. 6 to increase the thickness thereof. Folding or lapping device 63 is mounted for reciprocal movements over endless conveying belt 64 on which the web is lapped. The reciprocating device 63 is reciprocated in a direction parallel to the direction of movement of the belt or at a direction transverse tothe direction of the movement of the belt such as at an angle up to about degrees thereto. When reciprocating at an angle to the direction of the belt, a cross lapped material is obtained. In either instance, the speed of the reciprocation relative to the speed of the advancement of the belt can be adjusted to increase or decrease the thickness or the amount of lapping produced. The reciprocating lapping of web and the movement of belt 64 coact to form a continuous mutli-ply web structure 66. It will be noted that if reciprocating device 63 moves parallel to belt 64, the filaments in each ply are all orientated lengthwise of the web and thus linear to the direction of the advance of the web, whereas if reciprocating device 63 moves transversely to the belt, the filaments in each ply are orientated angularly to the direction of advance of the web and, of course, angular relative to the filaments in the next adjacent pile. The number of piles per unit length of web 66 and the angle of cross lapping is determined by the relative speeds of the belt, the feed rates of web 10 to reciprocating device 63, the reciprocating rate and the angle of traverse, if any, to the direction of movement of belt 64.
The multi-ply web structure 66, whether of the linear lapped or cross lapped type, produced by the method of FIG. 6, is bonded or otherwise subject to further treatments to dimensionally stabilize it as herein described, for use in the manufacture of particular end products. Thus, multi-ply web 66 may be taken up in a suitable form, such as a roll, or sent directly for further processing. Such further processing includes the formation of the lapped product into items such as battings or stufiings for pillows, comforters, cushions, upholstery, insulating padding and the like. In the formation of materials such as comforters, sleeping bags, cushioning materials and the like, the various processing techniques described in FIGS. 7, 8, 9 and 10 are preferably used to achieve the greater degree of dimensional stability desired. As described hereinbefore, the lapped material can be bonded in its entirey or spot bonded as may be desired.
For use in products wherein a bonding agent is deemed to be undesirable or incapable of imparting the ultimate physical characteristics to the end product, the web of the present invention, whether lapped or unlapped, may be fed into and through a stitching device as illustrated in FIGS. 8 and 9. Stitching device 68 can be operated on the web alone without an additional sheet material, or as is often desired for cushioning materials such as comforters, insulating clothing, sleeping bags and the like, in conjunction with a dimensionally stable sheet material such as a knitted, woven or nonwoven fabric. The sheet material is applied to either or both sides of the web. The web is thus stitched either crosswise, at regular intervals, in singular or multiple zigzag patterns or quliting as indicated at 70 in FIG. 8.
The operation is preferably effected by feeding the web into the stitching device by first passing the web through a slack absorbing mechanism shown diagrammatically in FIGS. 8 and 9 to apply a tension along the direction of the fibers. This is readily accomplished by a number of methods such as the use of guide rollers 71, 72 and 73 wherein middle roller 72 is mounted for vertical displacement toward and away from stationary rollers 71 and 73 as indicated by broken lines in FIG. 9. In instances where the web material is cross lapped so that the orientation of the fibers is generally across the width, the tensioning is then preferably also applied across the width so as to exert a tension along the length of the fibers. The tensioning is preferably in an amount insufficient to remove the crimp from the fibers but sufficient to stretch the fibers to their full length. This pretensioning has been found to unexpectedly increase the loft or bulkiness to the end product. Such bulkiness increases the cushioning and insulating value of the final product.
As illustrated in FIGS. 7, 10, and ll, the spread web can be dimensionally stabilized in the form of a single ply or multi-ply web by attachment to one or more additional layers of sheet material. As illustrated in FIG. 7, a
single or multi-ply spread web 10 is dimensionally stabilized by feeding it toward a pair of calender rolls 74 and 75 to which is simultaneously fed another sheet material 76 taken from a supply roll 77. In the method specifically illustrated, sheet material 76 is first passed over a guide 78 and hence to an applicator roll system 79 where a suitable bonding agent is applied to at least the surface of sheet material 76 to be contacted by web 10. The sheet material is then passed through calender 74 and 75 with web 10. Sheet material 76 may be any of numerous materials, particularly fibrous materials such as woven scrim fabric, knitted fabric such as tricot fabric, staple fiber, nonwoven batting such as a needle punched nonwoven, or nonfibrous backing material such as sponge rubber, plastic sheeting and the like as well as paper and leather. Web 10 may have been stabilized as hereinbefore described such as by bonding, stitching or the like or in the unstabilized form as it is produced. In the same manner, rather than bonding with an adhesive material, the laminate can be produced by stitching as hereinbefore described.
The combined spread web and sheet material, upon curing of the binding agent, results in a unitary laminate structure 80 which can be taken up for storage or immediately further processed into end products such as garments, drapery fabrics, and the like. It will be further understood that sheet material 76 may be, rather than the aforementioned sheet materials such as a woven, knitted or staple-fiber, nonwoven fabric, a web of opened and spread tow similar to web 10. Thus, either or both of the webs may be a single-ply structure, either or both of the webs may be linearly or cross-lapped and either or both of the webs may have been previously stabilized by prior bonding, needling or stitching or laminating operations. Especially where both webs are of the same type, such as both are linear lapped or single ply, it is preferred, in accordance with still another aspect of this invention, to laminate them with the filament orientations or adjacent web sections transversed to each other to form right angles to one another. To accomplish this,the respective spread tow or web is cut or otherwise formed in the desired filament direction such as by cross lapping one web onto another Web.
As previously indicated, the laminating operation may involve more than one web or sheet material. This is more specifically illustrated in FIG. 10 wherein 3 webs, X, Y, and Z or a combination of webs and sheet materials are sandwiched together. 'Ihus, X, Y, and Z may all be singleply, opened and spread tow bands 10 which, prior to lamination are fed through respective layering devices 81, 82, and 83. For example, devices 81 and 83 may produce linearly lapped webs while device 82 produces a cross lapped web, or vice versa. Additionally, X and Z can be sheet material such as knitted, woven or nonwoven fabric and Y can be a spread web, cross lapped web, linearly lapped web or the like. The resulting combination of X, Y, and Z is then fed to a pair of calender rolls 84 and 85 with or without the application of a bonding agent to adhere the laminates. Or, as more specifically illustrated, stitching device 86 is used to bind the sandwiched materials together in the manner illustrated in FIGS. 8 and 9. 1
In another aspect of the foregoing laminating process, a laminate structure is formed with a pleated web 55 of the type produced in accordance with FIG. 4. This aspect is more specifically illustrated. in FIG. 11 wherein bonded or unbonded spread tow band 10 is fed by means of feed rollers or the like through folding means 53 and into stutter box 52. Simultaneously therewith, two bands of sheet material 76 are fed into the stuffer box on the opposite sides of loosely pleated web 54. Again, sheet materials 76 may be scrim fabrics or any of the previously described materials such as those described for FIG. 7.
As web 54 advances through the narrowing funnel intake of stufiFer box 52 into heater section 56, it is compacted to form web 55. At the same time, the bands of sheet material 76 are pressed into intimate contact with the opposite faces of web 55. To achieve adhesion of sheet material 76 to web 55, web is first passed through a bonding agent applicator device 48 and/ or bands of sheet material 76 are passed through respective bonding agent applicator systems 79 Or the like. The resulting composite fabric structure, which is illustrated in FIG. 12 in an enlarged partial sectional view wherein the vertical lines represent the spread web, is then ready to be taken up by any suitable take up means for storage or further processing into end use items. This produced fabric is particularly useful for upholstery coverings, insulating wear, sleeping bags, mattress pads, and the like cushioning and insulating materials. It will be readily recognized, that the density of the fibrous fabric produced by the method illustrated in FIG. 11, can be readily controlled by controlling the feed rates of the various components such as the sheet material 76. Thus, a wide variety of fabric textures can be readily produced by this method.
The invention will be described more fully by reference to the following examples which illustrate certain preferred embodiments of the present invention.
EXAMPLE 1 A polyester continuous filament tow having a total denier of 220,000, a denier per filament of 5.0 and about 8 crimps per inch was processed through a tow opening and crimp deregistering apparatus of the threaded roll type disclosed in the hereinbefore mentioned Dunlap etal. patent, said apparatus having a first pair of rolls operating at a speed of about 21.3 yards per minute, and a second pair of rolls operating at a speed of about 30 yards per minute. The resulting opened tow was in the form of a band about 12 inches wide. Thereafter, the opened tow was passed under a tension of approximately 8 ounces over a spreading device consisting of 2 curved bars. The spread tow band was approximately 40 inches wide and had a base weight of about 0.8 ounce per square yard. The web so formed was fed to a laying device and there formed into a multi-ply cross lapped structure. The latter is then dimensionally stabilized by laminating to a woven scrim fabric in accordance with FIG. 7, using about 20 weight percent butadiene urea formaldehyde emulsion solids pickup. The resulting product is particularly useful for furniture batting and other cushioning material.
EXAMPLE 2 The same type polyester tow of Example 1 was again deregistered in accordance with FIG. 1 using the operating speeds of Example 1. The tow was then spread from a band of about 12 inches to a width of about 60 inches by passing the tow through two air spreaders. The spread web weighed about 0.5 ounce per square yard. The web is then cross lapped in accordance with FIG. 6 to a thickness of 7 to 10 webs and dimensionally stabilized by applying an acrylic emulsion bonding agent to the filament and calendering. The resulting batting is particularly suited for use as carpet backing and carpet underlay pads.
EXAMPLE 3 A polyester continuous filament tow having a total denier of 225,000 and a denier per filament of 5.0 was processed on the threaded roll tow opening device as in Examples 1 and 2 and thereafter spread to form a band having a width of approximately 28 inches and a base weight of about 1 ounce per square yard prior to being linearly lapped. Sixteen web segments of this band were then plied together, as follows: four webs with filaments oriented in one direction; atop these, eight webs with their filaments arranged crosswise to the filaments 0f the lower Webs; atop these, four webs with their filaments parallel to those of the bottom webs. This structure is then stitched in a quilted pattern thereby dimensionally stabilizing the nonwoven material the resulting product is extremely bulky, soft, and resilient. It is particularly useful for cushioning material such as furniture batting, carpet underlay padding and insulating material. In addition to the greatest tensile strength of this product compared to staple fiber batting, a greater force is required to remove tufts of fiber, as evidenced by the lower tendency of the tow batt to fuzz up under abrasion. Moreover, the tow batt is found to be completely free of the problem of fiber migration and to have superior launderability properties, which greatly enhances its suitability for use as a fabric in the manufacture of blankets, clothing, etc.
In the same manner, when the end use is for items such as mattress pads, insulating clothing, and the like, a woven knitted or needle-punched or bonded nonwoven is applied to one or both sides of the web material prior to stitching.
EXAMPLE 4 A 1.6 denier per filament, 40,000 total denier dull acetate continuous filament tow was processed on the threaded roll tow opening apparatus of the Dunlap et a1. patent in which the first set of rolls were operated at a speed of about feet per minute, and the second set of rolls at about 220 feet per minute. The opened tow band, which was about 4 inches wide, was then spread to a width of 12 inches. The web so formed was found to have a base weight of 0.53 ounce per square yard. A portion of this web was passed at a speed of 150 feet per minute through a chamber containing triacetin mist as a bonding agent in accordance with FIG. 2. The ultimate bonded web was found to have a base weight of 0.55 ounce per square yard and to be of increased dimensional stability. This product was particularly suited for further processing as illusrated in FIGS. 4, 6, 7, 8, 10, and 11.
EXAMPLE 5 A second portion of the spread tow web of Example 4 was bonded in the same manner but additionally was calendered at a temperature of 225 F. and no pressure other than the contact pressure of the calender rolls. The bonded web was found to have a base weight of 0.55 ounce per square yard. The tow processed as in accordance with this and the preceding example, is advantageously used as backing material, pattern material, industrial carrier webs, sanitary napkin covers, seed bed material, filtration fabrics, reinforcing material for plastic laminates, etc.
EXAMPLE 6 A polyester continuous filament tow having a total denier of 225,000 and a denier per filament of 5.0 was opened and spread into a band 40 inches wide in accordance with FIG. 1 as set forth in the preceding examples, with the first pair of rolls of the tow opening apparatus operated at a speed of about 12 yards per minute, and the second pair of rolls at a speed of about 21.4 yards per minute. The spread web was then cross lapped into a batting having a base weight of 9.6 ounces per square yard and a width of 27 inches. The batting was interposed between two sheets of cotton scrim, and thereafter both sides of the sandwich structure were sprayed with a bonding agent composed of a water dispersion containing 55 percent by weight of modified vinyl chloride polymer and 1 part water. Finally the entire laminated structure was dried by being passed twice at a speed of 8 feet per minute through an infra-red oven set at 320 degrees Fahrenheit. The finished fabric had a base weight of 21.1 ounces per square yard and a height of 2 inches at zero compression, and was found to be free of fiber migration and to compare favorably with a corresponding staple fiber sandwich in the properties of compressibility, recovery, retention of bulk, etc. This product is particularly suited for use in the manufacture of upholstery stuffing, furnace and air conditioner air filters, sleeping bag insulation, blanket interliners, etc.
EXAMPLE 7 An opened and spread polyester continuous filament tow having a total denier of 220,000 and a denier per filament of 5.0 was processed into a linearly lapped web 36 inches wide. Opening was accomplished by means of the threaded roll apparatus as described in Example 1. Three portions of this web were plied with the filaments of the middle web oriented transversely to the filaments of the outer webs. This assembly, having a base weight of 2.7 ounces per square yard, was then sandwiched between two plies of woven nylon fabric. The sandwiched layers were then secured by sewing a quilted pattern of 2 inch square quilts across the nylon fabric while applying a tension to the fibers along their longitudinal direction. The tension applied was sufiicient to stretch the fibers but insufficient to permanently remove the crimp. After quilting, the tension was released. The finished structure was possessed of a high loft, excellent washability and insulating qualities and was found to be suitable for use in such products as insulated garments, comforters, quilts, bedspreads, etc. The product was free of fiber migration, as well as being highly resistant to the removal of tufts of fibers vis-a-vis a corresponding staple fiber structure.
EXAMPLE 8 A cellulose acetate continuous filament tow having a total denier of 50,000 and a denier per filament of 3.2 was processed by the threaded roll apparatus into an opened and spread band or web 12 inches wide in the manner hereinbefore set forth. Two portions of the resulting web were plied together with the filaments in each ply oriented transversely to the filaments in the other ply. The assembly was then passed through a spot bonding apparatus which applied to the filamentary structure discrete and overlapping circular areas of triacetin, in accordance with that illustrated in FIG. 5, covering approximately 25 percent of the total surface area of the fabric structure. The bonded fabric was found to have good strength properties both lengthwise and widthwise and was adapted for use in the production of interliners, surgical dressings, hand towels and diapers. In comparison with heretofore known spot bonded staple fiber nonwoven fabrics, the spot bonded continuous filament nonwoven fabric was found to be free of fiber migration and also to compare favorably with the staple fiber fabrics in such textile properties as softness, flexibility, drape and loft.
While there have been described various embodiments of the present invention, the method described is not intended to be understood as limiting the scope of the invention as it is realized that changes therein are possible.
What is claimed is:
1. A process for producing a nonwoven continuous filament product comprising the steps of longitudinally advancing a crimped continuous filament tow, subjecting said tow while said tow is in motion to a differential gripping action at a plurality of points spaced from one another transversely of said tow and defined by at least one pair of opposed surfaces one of which is profiled and the other of which is smooth, to effect a deregistration of the crimps of said tow, spreading the deregistered tow to a weight of less than one ounce per square yard to produce a web and subsequently dimensionally stabilizing the web to produce a nonwowen continuous filament product.
2. The process of claim 1 wherein the web is dimensionally stabliized by applying a bonding agent to the fibers thereby bonding the web.
3. The process of claim 2 wherein the web is pleated.
4. The process of claim 1 wherein the web is dimen- 12 sionally stabilized by attaching the web to a sheet material.
5. The process of claim 4 wherein the web is attached to a sheet material by stitching.
6. The process of claim 4 wherein the web is laminated between at least two fibrous sheet materials.
7. The process of claim 4 wherein the web is stabilized by placing the web between at least two sheet materials placing a tension on the web in the filament direction, stitching the web and sheet material together, and subsequently releasing the applied tension.
8. The process of claim 4 wherein the web is linearly lapped prior to attaching to said sheet material.
9. The process of claim 4 wherein the web is crosslapped prior to attaching to said sheet material.
10. The process of claim 4 wherein the web is attached to the sheet material by applying a bonding agent to at least one of said web and sheet material and subsequently pressing said materials together.
11. The process of claim 10 wherein the web is pleated.
12. The process of claim 10 wherein the web is pleated, compressed and bonded between two fibrous sheet materials.
13. The process of claim 1 wherein the tow is comprised of polyethylene terephthalate filaments.
14. The process of claim 1 wherein the tow is comprised of cellulose acetate filaments.
15. The process of claim 1 wherein the deregistered tow is spread to a weight of less than about 1 ounce per square yard, said web being stabilized by lapping the web to produce a multi-ply web, placing the web between at least two fibrous sheet materials, placing a tension on the web in the filament direction, stitching the web and sheet material together and subsequently releasing the applied tension. I
16. A continuous filament product comprising a crimped deregistered spread web of continuous filaments, wherein said web comprises continuous filament tow having the crimps of said tow deregistered by the difi'erential gripping action of at least one pair of opposed surfaces one of which is profiled and the other of which is smooth and said web is initially spread to a weight less than about one ounce per square yard, said web being dimensionally stabilized by the application of supporting means at least transversely to the primary orientation of the continuous filaments.
17. The product of claim 16 wherein the web is crosslapped to a weight more than the original spread weight.
18. The product of claim 16 wherein the web is linearly lapped to a weight more than the original spread weight.
19. The product of claim 16 wherein the supporting means of said web is a sheet material attached to said web.
20. The product of claim 19 wherein the sheet material is a fibrous material.
21. The product of claim 19 wherein the web is attached to the sheet material by stitching.
22. The product of claim 19 wherein a multiple of said webs are attached by stitching between at least two fibrous sheet materials.
23. The product of claim 19 wherein the web is bonded with a bonding agent to said fibrous sheet material.
24. The product of claim 23 wherein the web is pleated and bonded between at least two fibrous sheet materials.
25. The product of claim 16 wherein the web is comprised of polyethylene terephthalate filaments.
26. The product of claim 16 wherein the web is comprised of cellulose acetate filaments.
27. The product of claim 16 wherein the supporting means of said web is spot bonding.
28. A quilted article comprising a crimped deregistered spread web of continuous filaments sandwiched between at least two fabric sheet materials, wherein said spread web comprises continuous filament tow having the crimps of said tow deregistered by the differential gripping action 13 of at least one pair of opposed surfaces, at least one of which is profiled, and said web is initially spread to a weight less than about one ounce per square yard, said Web being dimensionally stabilized by the application of at least one of said fabric sheet materials transversely t0 5 References Cited UNITED STATES PATENTS 4/1957 Smith 28-72 X 1/1962 Smith 19-65 14 3,071,783 1/1963 Gamble 5-337 3,235,935 2/ 1966 Daruwalla 28-722 FOREIGN PATENTS 1,258,476 3/1961 France.
ROBERT F. BURNETT, Primary Examiner R. L. MAY, Assistant Examiner U.S. Cl. X.R.