IE43005B1 - Improvements relating to stretchable non-woven fabrics - Google Patents

Description

This application pertains generally to synthetic polymer non-woven fabrics and to methods of making such, fabrics and more particularly to the production of nonwoven fabrics comprising self adhesive filaments. This i invention is of particular utility in connection with the production of cloths of low basis weight and/or high, porosity and/or of low modulus of elasticity in one or more directions having good draping qualities.

In accordance with the present invention, a non0 woven fabric comprises two types of organic polymer fiber., one of which is elastomeric (as herein defined) and the,, other of which is elongatable but non-elastic (as herein defined), at least One of the types of fibers being dispersed to provide frequent random fiber crossings, at least the majority of which are autogenously bonded with a bond strength'sufficient to permit the non-elastic fibers to be stretched between the bonds with substantially no breakage of said bonds, the bonded crossings including bonds both within and between the fiber types.

Autogenous bonding results from the effects of heat (whether applied at the bonding location or remaining from a- previous step) and pressure alone and without the application of solvent or adhesive. Such a fabric represents the basic starting material, but achieves its i full potential only after a subsequent step of mechanical 3 0 0 5 - 3 working, preferably by stretching in at least one direction, followed by relaxation, so as to elongate at least a proportion of the non-elastic fibers, to give a low modulus of elasticity in the direction of stretching. While some molecular orientation may occur to the non-elastic filaments during draw-down from the spinnerette to textile denier, it is important that full molecular orientation should not occur so that stretching of the non-elastic filaments may be accomplished during the final stretching of the bonded cloth. Accordingly, for maximum toughness and tear-resistance of the final cloth, preferably little or no molecular orientation is induced during drawdown from the spinnerette. It is also within the ambit of the present invention, however, to provide some degree of molecular orientation of the relatively non-elastic filaments prior to final working or stretching of the bonded cloth, either during drawdown and diameter reduction from the spinnerette or during passage of the filaments through the draw apparatus, providing enough potential molecular orientation remains in the filaments to enable final stretching of the cloth without breaking the filaments.

A fiber in accordance with the present invention, is, in fact, elongatable in all directions, even as bonded and prior to any preworking due to the presence of randomly dispersed elastomeric filaments. The cloth will give, without tearing and quickly recover to substantially its original dimension developing low modulus elasticity.

In its as bonded condition, and prior to any mechanical working, the cloth has a very high elastic modulus.

Once stretched and relaxed however, the elastic modulus for succeeding stretch cycles in the same direction is substantially reduced. Hence, by directional working or stretching under controlled loads followed by relaxation, a directionally oriented elasticity of low modulus can be 1300 5 - 4 readily developed in any desired direction and the cloth may be selectively developed thereby as a one-way or a two-way stretch material. By selection of polymers; filament size and relative proportions; fabric weight? bonding patterns, temperatures and pressures; degree of calendering; and pre-work conditions; the fabric of the present invention may be made in accordance herewith having characteristics, for example, of either knit or woven conventional cloth materials, or characteristics unique to the cloth structure hereof. The elastic modulus may also be tailored to provide soft and supple readily stretchable cloth or cloth having the modulus of conventional narrow or wide elastics or the modulus of two-way stretch material. Even in very heavy weight elastic cloths, however, porosity may be maintained and up to about 90% af the material may be elastomeric, with the remaining as little as 10% non-elastic yet eliminating any rubbery feel thereof in the completed cloth. The stretching of the fabric may be achieved by the use of accelerating roll sets, tenter frames or ribbed rolls or other devices as known by those skilled in the art, and the stretching is preferably incremental.

The weld bonded coherent cloth when so formed, when stretched in at least one direction and relaxed develops a low modulus of elasticity as the elastomeric filaments retract the cloth to its approximate orlgnal area dimensions together with a suppleness and a soft feel and hand as the elongatable but non-elastic filaments, relatively permanently elongated by the stretching, are looped, bulked and bunched between the bond points by the retracting elastomeric filaments.

It will therefore be apparent that although the preferred process is one employing essentially continuous filaments, it is equally possible to carry out the invention with mixtures of non-elastic staple length j fibers formed into webs by such techniques as carding or 3 0 ο 3 air layering well known in the art winch webs can then be bonded autogenously. Similarly, it will be apparent that the same mixture of fibers cut to lengths suitable for web forming on paper machines equid also be bonded, stretched and relaxed to form a fahric in accordance with the invention.

In addition to being elastic and thus convertible into form fitting garments, such cloth can be produced with weight, porosity, strength, modulus, thickness, suppleness, resiliency, hand, and/or visual and surface properties adjusted to meet a number of specific cloth material end use requiremants.

Although the filaments may be bonded in smooth heated roll nips to bond substantially all of the filament crossing points and meet the elastic definition of the material, spot bonding at selected intervals may be utilized to alter the hand of the elastic cloth over rather wide limits. Differing emboss or bond patterns may texture the cloth material to provide appearance and feel of differing conventionally woven or knitted fabrics. Bond frequency, at least within a range of 28-10,000 bond points per square inch, does not appear to appreciably effect the strength or elastic properties of the cloth hereof, but can effect the appearance and feel of the cloth. Hence, close spacing of the bond points produces little lofting of the elongated non-elastic filaments and a low caliper cloth while further spaced apart bondings may produce substantial lofting of the elongated non-elastic filaments and a highly fuzzy or napped cloth of high caliper (at low pressure caliper measurements).

As heretofore pointed out, porous elastics of high elastomeric content, as high as about 90% and of high basic weights, as high as about 200 grams per square meter can be produced in accordance with this aspect of 300 S - 6 the present invention. Very supple and soft cloths may also be made, particularly at much lower basis weights and elastomeric content, preferably from 20% to 65% elastomeric fiber content. When such a cloth is mechanii cally worked after bonding, as by stretching to substantially exceed the elastic limit of the nonelastic fibers without exceeding the elongation to break of either filament and then relaxed, only the relatively low modulus of the elastomeric filaments resists the .0 next cycle of extention until the first cycle extension length is reached. This low modulus of elasticity in the direction or directions of stretch and high modulus at the extension limit defined by the first cycle stretch can be used to provide comfortable fit of garments fabricated therefrom coupled with high ultimate strength. To sum up, a fabric in accordance with the invention is produced by a method comprising the steps of substantially continuously forwarding synthetic organic elastomeric (as herein defined) and elongatable but non-elastic (as herein defined) fibers onto a porous forming surface, autogenously bonding at least a proportion of the fiber crossings to provide a coherent bonded fabric web, and mechanically working the bonded web to elongate at least some of the fibers in at least one direction so i that retraction of the elastomeric fibers provides looping and bunching of the elongated non-elastic fibers to thereby develop a low modulus of elasticity in at least one direction.

This will now be described in more detail, by way of example, with reference to the accompanying drawings which illustrate an apparatus and method which is directed to the production of a non-woven fabric whose filaments are disposed in an irregular wave pattern. In the drawings :Figure 1 is a schematic diagrammatic representation of a portion of a cloth made in accordance with the u g - 7 principles of the present invention as bonded, and prior to stretching; Figure 2 is a schematic diagrammatic representation similar to Figure 1 showing the cloth of Figure 1 expanded generally uniformly in all directions to stretch the fibers thereof; Figure 3 is a schematic diagrammatic representation similar to the preceding figures illustrating the cloth relaxed, after stretching, with elastomeric fila1() merits thereof retracted and the non-elastic filaments [.hereof hundred and looped Lhereby; Figure 4 is an enlarged devotional cross section illustration of an extruder head and a linear die head or spinnerette; Figure 5 is an enlarged plan view of a portion of the die head of Figure 4 taken along line 5-5 of Figure 4; Figure 6 is a further enlarged plan view of a portion of the die head of the preceding figures illust20 rating the die plate thereof; Figure 7 is an elevational cross-section view of the die plate taken along line 7-7 of Figure 6; Figure 8 is a diagrammatic cabinet view illustration of apparatus for making the cloth of the present invention in accordance with a preferred embodiment of the methods hereof; Figure 9 is an enlarged cross-sectional illustration of the formation means of the apparatus shown in Figure 8 showing details of a draw vacuum box air deflecting and directing control plate, filament doctoring and directing means or air jet device, and a formation vacuum box; Figure 10 is a partial view of an air jet device 4300 5 - 8 of the formation means shown in the previous figures, enlarged and viewed from the bottom; Figure 11 is a partial elevation cross-sectional view taken along line 11-11 of Figure 10,Figure 12 is a partial elevational crosssectional view taken along line 12-12 of Figure 10,Deflnitions A fiber is defined for the purposes hereof as a pliable, cohesive, threadlike object having a length to width ratio exceeding 100 to 1 and formed of a thermoplastic polymer.

A filament is defined for the purposes hereof as a single continuous man-made fiber having an indefinite length.

A staple length fiber is defined for the purposes hereof as a filament cut to 1-6 inches in length.

Textile denier fiber is defined for the purpose hereof as 1-15 denier.

A short cut fiber is defined for the purpose hereof 3 as a filament cut to less than 1 inch in length, and typically from 1/4 inch to 1 inch in length.

A fiber forming polymer is defined for the purpose hereof as an organic thermoplastic polymer that can be melt spun to form a filament. j Melt spinning is defined for the purpose hereof as the process in v/hich a fiber is formed by the extrusion of a melted polymer into a cooling zone as opposed to wet spinning (extrusion of a solution into a coagulating bath) or dry spinning (extrusion of a ) solution to form a fiber by evaporation of the solvent).

A monofilament is defined for the purpose hereof as a filament exceeding 15 denier.

An elastomeric fiber is defined for the purpose hereof as a polymer in fiber form which exhibits less 4300 5 - 9 than 10¾ permanent increase in length along the fiber after 50 short interval (less than 1 minute/cycle) cycles of extension carried out at room temperature to 150% of original length, for example, extension from 2 inches to 3 inches length.

A non-elastic fiber is defined for the purpose hereof as a polymer in fiber form which after stretching along the fiber to 150% or more of original length (for example from 2 to 3 or more inches) as any temperature between room conditions (70°C) and the glass transition temperature of the polymer and subsequent releasing of the fiber results in a permanent elongation equal to 50% or more of the stretch applied.

Random laid is defined for the purpose hereof as a process of formation of non-woven fabrics by forwarding fibers or filaments to a location spaced apart from a collection surface and thereafter laying down the fibers or filaments on the collection surface without instantaneous or precise control at all instants of the fiber of filament location relative the collection surface. The movements of the fibers or filaments are generally statistically determinable, with the instantaneous positions and flexings thereof being controlled by looping forces, Coriolis forces, Rayleigh movements of the like.

Random fiber or filament crossings is defined for the purpose hereof as the crossing produced between random laid fibers or filaments and other random laid or non-random laid fibers, filaments or mono-filaments, A self adhesive fiber is a naturally self adhesive fiber or a fiber, such as polyurethane, which retains the property of being self adhesive for at least a period of time after cooling from the melt.

With reference now to the drawing and particularly to Figures 1 to 3 thereof, there is shown and illustrated -loin enlarged diagrammatic and schematic form a plan view of a representative portion of a cloth web made in accordance with the present invention comprising two types of filaments, non-elastic filaments 2 and elastomeric filaments 4, dispersed to provide frequent fiber crossings 6 whereat the filaments are bonded to one another as by heat and pressure, to form the coherent bonded cloth web.

The non-elastic filaments 2 and the elastomeric filaments 4 are preferably continuous filaments extruded or melt spun through linear spinnerettes and subsequently mechanically drawn as they exit therefrom and reduced thereby to textile denier. The non-elastic filaments 2 and the elastomeric filaments 4 need not necessarily, however, comprise continuous filaments and may, for example, comprise in whole or in part, staple or cut length fibers.

The fibers, if not both substantially continuous filaments, should preferably each be of sufficient length, however, as to permit, on the average, at least two bonded crossings with fibers of the other type. Each elastomeric fiber or filament may preferably, therefore, be bonded either directly or indirectly with at least two non-elastic fibers or filaments and each non-elastic fiber or filament may preferably therefore, be bonded either directly or indirectly, with at least two elastomeric fibers or filaments.

The bondings at the fiber crossings 6 are autogenous, that is, produced by the application of heat and pressure along and without any solvent or adhesive application. Moreover, the non-elastic filaments 2 and the elastomeric filaments 4 may be bonded at each crossing point 6, or the cloth may be spot bonded to bond only some of the crossing points 6 and, provide an embossed surface to the cloth. The non-elastic filaments 2 and 3 0 (j 5 -lithe elastomeric filaments 4 may also be either mixed within a single generally homogenous layer or may be formed as distinct layers, one above the other, laminated together. The filaments 2 and 4 may, further, be either single component filaments or may be multicomponent filaments made of mixed or co-extruded polymers or copolymers.

The cloth may be produced by separately extruding or melt spinning streams of filaments of each polymer, separately drawing each stream of filaments to reduce the individual filaments thereof to textile denier or by interleaving the streams and simultaneously drawing them to textile denier and delivering the streams of filaments while maintaining the stream alignment and distribution to divergence points closely adjacent a porous forming surface and thereat directing the textile denier filaments for looping and random laydown and formation with well dispersed crossings on the forming surface, as over a vacuum box. The unbonded web produced thereby may then be bonded autogenously, to produce the bonded cloth structure illustrated in Figure 1. This bonded cloth structure may then be expanded, as by stretching, to elongate both the non-elastic filaments 2 and the elastomeric filaments 4, to the configuration illustrated in Figure 2.

When the stretched bonded cloth is released, the elastomeric filaments 4 retract the cloth to approximatly its original area dimensions. The non-elastic filaments 2, however, do not retract and the retraction of the elastomeric filaments 4 is effective to causelooping, bulking and bunching of the non-claslie fi laments 2, as shown in Figure 3, as the bond points 6 return to substantially their original positions.

Following stretching and relaxation, therefore, the cloth has a low modulus of elasticity in any direction wherein it was previously stretched and relaxed, - 12 within a range of extensions up to the limit of extension to which the cloth had been previously expanded. Within this range, only the elastomeric filaments 4 need be stretched during subsequent stretch cycles and the non5 elastic filaments 2 need be merely straightened. Hence, the modulus of elasticity is substantially entirely that of the previously stretched elastomeric filaments 4, and the cloth exhibits true elasticity.

The non-elastic filaments 2 add body to the cloth LO structure as well as increasing its opacity. Further, the looped and bunched non-elastic filaments 2 provide a soft nap to the cloth structure, eliminating the sticky or tacky feel of the elastomeric filaments. The nonelastic filaments 2 also limit the stretch characteristics .5 so that the cloth is not easily deformed beyond the elastic range built in by the initial stretching thereof used to develop its low modulus of elasticity. As heretofore pointed out, the elastomeric and non-elastic filaments may be mixed in a generally homogenous layer.

An elastomeric filament layer may be laminated between a pair of non-elastic filament layers, or vice versa. Additional layers, including cut length fiber layers and/ or cellulosic or wood pulp layers may also be incorporated into the cloth, without departure from the princip5 les of the present invention. Yet further, the looped and bunched non-elastic filaments may be set by embossing during bonding or as a post bonding step to provide a surface appearance similar to conventionally knit or woven cloth.

) As has been herein elsewhere pointed out, it is also ah aspect of the present invention to provide such embossing, particularly, although not necessarily, during bonding by collecting the dispersed filaments on a porous woven forming fabric having generally uniform knuekle heights and x>as«lng tin? forming fabric· and 3 0 0 5 - 13 supported filaments through a pressure bonding nip to emboss the forming fabric knuckle pattern into the collected filaments while bonding them into a coherent bonded cloth. In this way very sheer and lightweight cloths of either a single type of filament, or of mixed elastomeric and non-elastic filaments may be produced.

As has been heretofore pointed out, the mixed or dual filament (i.e. comprising both elastomeric and elongatable but non-elastic filaments) cloth of the present invention may be mechanically worked to develop a low modulus of elasticity in either a plurality of directions, through stretching or expansion in such plurality of directions or in only a single primary direction through stretching in only a single direction, followed by relaxation to produce a cloth having twoway and one-way stretch characteristics, respectively.

Bi-directional expansion (as schematically illustrated in Figure 2) may be achieved in a number of ways. Uniformity of expansion, simultaneously in at least two mutually perpendicular directions and generally uniformly and incrementally in all directions may even be achieved to provide uniform omnidirectional characteristics, by way of example only, but sandwiching the cloth between soft elastomeric or rubber blocks and compressing the sandwich, as by a platen press to expand the sandwich transversely the press pressure application direction. Unidirectional stretching may be achieved by a stretch frame, ribbed rolls or by other means known in the art.

With reference now to the drawing and particularly to Figure 8 thereof, there is shown apparatus for producing non-woven fabrics in accordance with the principles of the present invention and designated generally by the reference character 30. The apparatus 30 comprises filament forming means 32, filament drawing ύ 3 Ο Ο 5 - 14 means 34, web forming means 36 and web bonding means 38 which includes web moistening means 40, heated bonding nip means 42 and heating means 44 for heating a metallic screen or wire which passes through the nip means 42 with the nonwoven web.

As heretofore pointed out, the present invention is applicable to dual filament nonwoven webs comprising filaments of two distinct organic synthetic polymer types namely, an elastic material such as polyurethane and a LO second, elongatable but non-elastic material such as poly (ethylene teraphthalate) or polypropylene. Hence, the filament forming means 32 comprises a pair of generally linear dies or spinnerettes 46 provided with the melted polymer as by extruders, or the like, all as .5 more fully set forth below. The linear dies or spinnerettes 46 each provide a stream of polymeric monofilaments which are interleaved for mechanical draw to textile denier by the filament drawing means 34. The spinnerettes 46 preferably produce the streams of monofilaments in equally spaced apart linear arrays from a die orifice preferably of a diameter within the range of from 0.007 to 0.025 inches, being most preferably of about 0.015 inch in diameter. The die orifice need not necessarily be round. j The streams of monofilaments are preferably extruded generally downwardly through ambient air, with the linear dies and spinnerettes 46 being generally above the filament drawing means 34. The distance separating the linear spinnerettes 46 from each other and from the ι filament drawing means 34 are preferably, although not necessarily, limited to the smallest practicable distance to reduce the effects of stray air currents, and the like, upon the streams of filaments although the apparatus 30 has been successfully operated with the spin nerettes 46 about 8 feet above the drawing means 34. The 430G5 - 15 individual filaments of the streams of filaments generally solidify and set almost immediately after exciting from the orifices of the linear dies or spinnerettes 46 and, therefore, the linear dies or spinnerettes 46 may be positioned very close to the drawing means 34 and are preferably positioned as close as about 20 inches to the filament drawing means 34, With reference to Figures 4-7, the die apparatus for producing the streams of monofilaments may now be described and detailed. Each of the die heads or linear spinnerettes 46 (shown in outline in Figure 8) is connected with an extruder (not shown) by connecting, filtering and homogenizing means 272 which comprises (Figures 4) a filtering section 274 and a mixing section 276 to assure that only pure uniformly melted and blended polymer is fed to the orifices of the die head 46. The extruder may comprise a commercially available extruder such as, for example, a one-inch Model BF with a 24-inch length screw as manufactured by Sterling Extruder Corp., South Planfield, New Jersey. The filtering section 274 may comprise a flange portion 280 for connection with the output end of the extruder. The filtering section 274 may comprise a plurality of hollow sintered metal filtering tubes 281 extending longitudinally therethrough and being connected with a header plate 282, which may also be of sintered metal or which may be of solid metal. The distal ends 283 of the filtering tubes 281 are closed, so that the flow of melted polymer is inward through the walls of the filtering tubes 281 to the hollow center portion thereof, and then longitudinally therethrough and through the header plate 282. The tubes 281, and the header plate 282 if of sintered construction, preferably comprise an average pore size range of from 20 microns to 60 microns.

Hence, the extruder may be operated in a conventional horizontal position and the linear spinnerette or die US head 46 extrudes the stream of filaments generally vertically downwardly through ambient air to be pulled therefrom and drawn to textile denier by the drawing means 34 (Figure 8).

The die head 46 may comprise a manifold portion 310 having a manifold cavity 312 therein and a die plate 314 subjacent thereto and connected therewith, as by means of bolts 316. The die plate 314 may be provided with a generally rectangular polymer distributing groove LO 318 having generally tapered sides 320 and a generally flat floor 322 from which a plurality of monofilament forming orifices 324 extend downwardly through the die plate 314. To produce a 30 inch width stream of monofilaments (it being recalled that one aspect of this L5 invention is the delivery of the filaments to adjacent a formation location without disturbance of their linear array) and, accordingly, a 30 inch width web of cloth, the groove 318 may be approximately 30 inches in length and 1/2 inch in width. The groove 318 may be of approxi!0 mately two-tenths inch depth to produce a die thickness through which the monofilament forming orifices 324 extend of about 5/8 of an inch tapering from an inlet opening 326 of approximately 0.130 inch diameter to a cylindrical tubular passageway of 0.040 inch diameter and (5 about 3/8 inch length and thence to an exit opening 328 of 0.015 inch diameter and a land length for the Outlet orifice portion 330 of 0.075 inch diameter.

Means such as a sintered metal final filter 331 may be disposed within the groove 318 for providing final filtration of the polymer immediately prior to extrusion through the orifices 324 and for providing a controlled back pressure to the extruder and pressure drop to the spinnerette orifices 324 to enhance the uniformity of polymer feed thereto. The filter 331 also ;5 may provide protection against transverse polymer flow 3 0 G 5 - 17 between adjacent orifices which otherwise can produce instabilities in the polymer flow and random polymer starvation of the individual orifices.

For producing such a 30 inch width stream of monofilaments, 600 such monofilament forming orifices 324 may be provided in the floor 322 of the die plate 314 in three parallel rows longitudinal the groove 318, with the individual orifices being staggered and angularly offset approximately 22° from the transverse axis of the groove 318 (the transverse axis being perpendicular the longitudinal axes of the aforesaid rows) as shown and illustrated (particularly Figure 6). In other words, the projection of the die exit openings 328 of the orifices 324 perpendicular the die length is a uniformly spaced apart row. This offset enables formation and feeding of a stream of monofilaments from the die 314 which beaomes flat upon entrance to the draw apparatus aligned therewith.

Hence, viewing the die head 46 from the side (as viewed in Figures 4 and 7), each of the monofilament forming orifices 324 of the spinnerette 46 is laterally offset from each of its neighbouring orifices and the drawn filaments pulled from the extruded monofilaments can be interleaved into a single plane to form a single line or row of filaments entering into the draw apparatus 34.

Any tendencies which the filaments may show to be wrapped around the rolls of the draw roll set used in Examples I and II herein may be positively eliminated by the provision of a porous draw surface which may, for example, comprise a flexible woven belt 48 (Figure 8) and which is supported on a drive roll 50 and a plurality of idler rolls 52 to move along a closed path over a vacuum box 54 whereat the streams of filaments are engaged and held against the belt through drag of air passing inwardly through the porous belt 48 to the 3 0 0 5 vacuum box 54. As shown, the vacuum box 54 may be disposed internally of the path of the belt 48 adjacent one of the idler rolls 52 so that the belt 48 with the stream of filaments may be turned through, for example, 90° around that idler roll and thence, with the stream of drawn filaments still being held thereagainst, to the forming means 36. As the belt 48 passes through the forming means 36, the individual filaments of the streams of filaments are positively stripped therefrom by directing fluid therethrough as by an air doctoring and directing means. The air doctoring and directing means may comprise, by way of example, an air jet device designated generally by the reference character 56. The air doctoring and directing means not only strips or doctors the filaments from the belts 48 but also directs the filaments during and transfer therefrom to form a nonwoven web 58 on a porous collection surface 60 moving through the forming means 36 at a slower speed than that of the draw belt 48. The porous collection surface 60 may comprise a continu20 ous woven plastic belt or, preferably may comprise wire screen or formation wire to be described in more detail hereinafter which also passes through the bonding means 38. In the forming means 36, a formation vacuum box 62 is provided to further control the flow of air from the air jet device 56 through the draw belt 34 and to hold the nonwoven web 58 on the formation wire 60.

The formation wire 60 may carry the formed nonwoven web 58 from the forming means 36 to the bonding means 38.

The preferred bonding means 38 shown comprises web moistening means 40 for uniformly spraying or depositing moisture on the nonwoven web 58, heating means 44 for uniformly heating the formation wire 60 and heated nip means 42 for compressing the superposed nonwoven webs 58 and heated formation wire 60 to impress the knuckle i pattern of the formation wire 60 into the web 58 and thereby provide spot bonding and embossing of the web 58. 3 0 0 5 - 19 Following bonding, the web 58 is constrained against the healed roll of the nip for a brief period of time, as by being wrapped approximately 90° therearound, and is held on the wire 60 as it cools by a roll 166 to prevent shrinkage thereof. The bonded web is then pulled and separated from the formation wire 60 for subsequent finishing, stretching, and the like.

As heretofore pointed out, the drawing means 34 may comprise a continuous porous surface moving in a closed loop path and comprising, for example, a flexible belt supported on rolls 50 and 52. The rolls 50 and 52 are rotatably mounted,with their axes of rotation being parallel and parallel the longitudinal axes of the spinnerettes 46 and generally therebeneath so that the flat skeins of filaments melt spun generally downwardly from the spinnerettes 46 will engage the belt 48 without disturbing the filament distribution from that defined by the orifice pattern of the spinnerettes 46.

The draw bel t 48 may be ol woven consirueIion, ol at least about 30 x 30 mesh (I.e. 30 warp and 30 well threads per inch) and is preferably of 60 x 78 mesh (i.e., 60 weft and 78 warp threads per inch and may comprise a Style 78S PAPER MAKING WIRE FROM Appleton Wire Works, Appleton, Wisconsin which comprises PET (i.e., Poly(ethylene terephthalate)) polyester monofilaments woven with the weft or shute threads being woven around the warp threads in an over 3 Under 1 pattern to provide a surface to the belt, against which the streams of skeins of filaments engage, predominated by the woof or shute filaments. In other words, the surface of the belt 48 against which the streams of filaments impinge predominantly presents overlapping rod-like elements, defined by the over 3 passage of the weft or shute threads separated by the under 1 portions thereof. Hence, the dominant pattern of the draw surface of the draw belt 3 U li 5 - 20 48 is of rod-like elements extending generally perpendicular the filaments of the streams of filaments being drawn thereby.

As heretofore pointed out the means for applying 5 vacuum and pulling air inwardly through the belt 48 provides drag of air on the filaments to pull the streams of filaments against the draw belt 48 and may comprise the vacuum box 54 disposed within the looped draw belt 48.

The vacuum box 54 may comprise a forward wall 64, a bottom wall 66, and a rearward wall 68, (the direction of forward and rearward being defined relative the passage of the belt 48 across the bottom wall 66) as well as a top wall 70 and a pair of end walls 72. Means, such as a .5 duct 74 may be provided extending from, for example, the rearward wall 68 of the vacuum box 54 for connecting the vacuum box 54 with means (not shown) for drawing a vacuum, such as, for example a pump, fan, blower, compressor, or aspirator.

With reference now, in addition to Figure 8, Figures and 10, at least a portion of the bottom wall 66 of the vacuum box 54 may be provided with a plurality Cf apertures or slots 76, through which air may be drawn to also pass through the draw belt 48 to provide drag on the filaments during operation and hold the filaments positively against the draw belt 48 for movement therewith. As shown, the slots 76 are preferably elongated in the cross machine direction (i.e., parallel the axes of the rolls 50 and 52) and are preferably arranged in rows and ) staggered in the cross machine direction so that the projection in the machine direction of the vacuum profile in the cross machine direction is substantially uniform or at least at all points generates sufficient drag on each filament that slippage is positively eliminated. The rearward wall 68 of the vacuum box 54 may be provided 3 0 G 5 - 21 with a foot-like tapered projection portion 78 extending beneath the air jet device 56 and the better.·, wall cc and the slots 76 therein may be extended therebeneath, as (Figure 9), to provide positive air drag support of the filaments to a position as close as possible to the formation or divergence zone 80 whereat the filaments are doctored from the draw belt 48 and directed onto the formation wire 60.

Air control means such as a deflector and air directing plate 82 may be provided generally beneath the lower wall 66 of the vacuum box 54 angling generally upwardly, as shown, to direct ambient air towards the bottom wall 66 from forwardly of the adjacent idler roll 52 and forwardly along the bottom wall 66 of the vacuum box 54 so that the streams of filaments and the individual filaments thereof become entrained therein during start-up until reaching a point where air flow into the vacuum box 54 through the porous draw belt 48 provides sufficient drag on the filaments to hold the filaments tightly against the draw belt 48. The forward wall 64 of the vacuum box 54 may also, if desired, be slotted for filament control, although because of a Substantial absence of snubbing, this would provide little additional draw tension. The centrifugal force of any heavy globs or drops falling from the spinnerette onto the draw belt 48 will be thrown off during the turn around the roller 52 and means, such as a hot wire 88 may also be provided, as shown, so that any stray filaments or any filaments which have adhered to it any such oversized glob or drop will, upon being drawn by the entrained air into the region between the shield or deflector 82, but cut by the heated wire 88 and the freshly cut end will then be entrained into the air stream and thereby be self fed or pulled into and the forming means 36, the cut off pieces, with its adhered drop being thrown to the outside by the centrifugal force. - 22 Preferably, plate 82 is arranged obliquely, as shown, so that the decreasing space between the plate 82 and the draw belt 48 from the larger inlet or upstream region 84 (Figure 8) to the smaller exit or downstream region 96 (Figure 9) balances the rate of air flow into the vacuum box 54 through the draw belt 48 and slots 76 so that little or no air flows inwardly (i.e. towards the left in Figure 9) through the space or region 86 as will be explained more fully hereinbelow.

With further reference now to Figures 8, 9 and 10, and now in addition, to Figures 11 and 12, it may be seen that the air doctoring and directing means, which as heretofore set forth may comprise the air jet device 56, in turn may comprise a manifold member 90 to which may L5 be attached air Inlet means, such as one or more conduits 92 carried by the manifold member 90. There may also be provided a pair of cooperating nozzle plates 94 and 96 attached thereto by means of a pair of mounting plates 98 and 102 and means for controlling the flow of air to the Ό nozzle plates 94 and 96. The controlling means may comprise, in turn a flip-flop or flapper valve blade 104 and means such as an oscillatory shaft 106 for oscillating the flapper valve blade 104 between a pair of opposed value seat surfaces 108 and 110 provided on the nozzle mounting plates 98 and 102, respectively. In addition, means such as an eccentric drive system (not shown) may be provided for rocking or oscillating shaft 106 back and forth between contact with the valve seat surfaces 108 and 110. Further, a shim member 114 may be provided between the nozzle plates 94 and 96. The valve blade 104 is preferably sufficiently resilient as to be able to flex slightly after engaging the valve seat faces 108 and 110 that the range of its swing is limited thereby and the range of oscillation of the shaft 106 is not critical. > The nozzle plates 94 and 96 may be respectively 3 ϋ G 5 - 23 provided with a plurality of nozzle slots 116 and 118 separated by lands 120 and 122 which are angulated, as shown, so as to provide orifices, nozzles or jets that slant in opposite directions. That is, one set of jets, for example the jets 116 in the nozzle 94 may be inclined towards one side edge of the formation wire 60 and the other set of jets, for example the jets 118 in the nozzle plate 96 may be inclined towards the opposite side edge of the formation wire or belt 60. The slots 116 and 118 may, for example, be of a depth of within the range of about 0.005 inches to about 0.150 inches, may be of a width, within the range of about 0.005 inches to about 0.150 inches and the lands 120 and 122 therebetween may be with in l.lu· range from about .005 inches to .about' .()50 inches in width. In one specific prelorred embodImenl I lie slots lit and 1J8 are ().020 inches in depth. 0.075 inches in widtli and the lands 120 and 122 therebetween are of a width of 0.010 inches. The valve blade 104 in this embodiment is also of a width of .020 inches so as to alternately occlude each of the sets of orifices or jets formed by the slots 116 and 118 at the opposite extremities of the movement of the blade as shown in solid and phantom lines, respectively in the drawing and particularly Figures 10, and 12. Hence, the doctoring and forming jets of air are alternately directed first towards one side edge of the formation wire 60 by one set of jets defined by one of the sets of nozzle slots 116 or 118 and then towards the other side or edge of the formation wire 60 by the other set of jets defined by the other one of the sets nozzle slots 116 or 118. Therefore, individual filaments carried past the air jet device 56 are not only being doctored from the draw belt 48 but are being directed onto the formation wire 60 by the alternating jet action from the alternate occlusion of tiie oppositely directed sets of slots 116 and 118. In a specific embodiment, the operating arm driving the oscillating shaft 106 is swung through an arc of about 3° with a dwell at each end at a rate of at least about 500 oscillations per minute and preferably as high as about 1800 oscillations per minute.

The formation wire 60 may be supported on a series of idler rolls 148 to pass over the formation vacuum box 62 and through the heated bonding nip 42. The formation vacuum box 62 may be provided with an upper surface comprising a flow straightener of a honeycomb member 140 (Figure 9) fabricated, for example, of 1/8 inch diameter cells, and having a length of at least about 6 times the diameter and a wear plate 142 superjacent thereto which may also control air flow and may, for example, comprise about 20 percent open area.

Close control of the air flow during the draw process is vital so as not to disturb the filament distribution and to prevent unwanted filament contact, particularly between self adhesive filaments and, even more particularly, during the formation process, i.e., during the doctoring of the filaments from the draw belt and transfer thereof onto the formation wire. It is during and at this transfer or formation that flow control is most critical if the desired laydown and uniform formation is to be consistently attained. Hence, it is of paramount importance that stray or unwanted air movements in this crucial zone be positively prevented so that only the controlled flow of air from the air doctoring and flow directing means embodied, for example in the air jet device 56 to the formation vacuum box 62 effects the filaments during the transfer and formation phase. Ideally, all other air flow into, out of, through, or within the formation zone is positively precluded.

Hence, it has been pointed out that the plate 82 is preferably spaced from and at such an angle and is sufficiently long as to cover enough of the vacuum slots 76 and therefore control a large enough percentage of the area thereof and the flow therethrough so that the velocity head through the inlet 84 prevents significant flow of air 3 0 ϋ 5 - 25 through the exit 86 which would disturb the controlled flow of air from the air jet device 56 to the formation vacuum box 62 in the formation zone 80. To yet further isolate the formation zone 80, there may also be provided means to seal the outlet of the formation zone to undesired air movements.

A particularly effective method and means for sealing the outlet of the formation zone, particularly to preclude the inflow of any air therethrough into the formation zone may be provided by the provision of a freely rotatable and unconstrained seal roll 144 which is carried on the upper surface of the nonwoven web 58 and which engages the draw belt 48 on the lower surface thereof downstream of the air jet device 56. As shown (Figures 8 and 9), the draw belt 48 downstream of the air jet device is preferably diverging from the formation wire 60, forming an angle therebetween having its apex adjacent or within the formation zone 80.

The non-woven web 58 is soft and has a high coefficient of friction against the seal roll 144 which should be non-porous and may be metal, for example aluminum or steel. The draw belt 48, on the other hand is slick and has a very low coefficient of friction against the seal roll 144. In addition, since the roll 144 is supported by the non-woven web 58, its weight is applied downwardly to provide a large normal force against the nonwoven web 58 and, therefore, a large frictional force tending to rotate the roll 144 towards the formation zone 80 and against the draw belt 48. The slickness of the draw belt 48, the tendency of resultant air flow toward the vacuum box 62, and the various geometries all tend to maintain the seal roll 144 rolling on the nonwoven web 58 towards the formation or divergence zone 80 and slipping along the draw belt 48, as shown. The region 146 above the draw belt 48 and forward of the seal roll 144 may be left open, as shown, with little adverse effect on the formation 0 5 - 26 process or may be sealed, as with an extension from the nozzle plate 94 or mounting plate 98.

The formation wire 60 may be supported and driven by the bonding nip 42 and additionally supported on a plurality of idler rolls 148. The bonding nip 42 may comprise an upper roll 150 and a lower roll 152, the upper roll 150 being, for example, heated and of steel while the lower roll 152 may be covered with an elastomer layer 154 of a hardness of about 70-80 Shore D durometer hardness. A single forming belt of metallic screen construction may be utilized passing through both the forming and bonding sections, as shown, or separate belts may be utilized for the forming and bonding sections. In one embodiment of the apparatus, the forming wire 60 comprised a phosphor bronze xioven screen wire of 40 x 36 mesh having flattened knuckles.

The web moistening apparatus 40 provides a uniform spray of water to the nonwoven web 58 and may comprise a porous belt 156 of woven material similar to the draw belt 48 passed around a pair of rollers 158, at least one of which is rotably driven, by means, not shown. A fountain trough 160 may be provided through which the belt 156 is passed and an air knife 162 may be provided blowing through the porous belt 156 to provide a uniform spray of water 164 directed onto the nonwoven web 58 prior to its passage through the heated driven bonding nip 42.

A release agent of, for example, the fluorochemical type, such as DuPont Vydex or a release agent of the quaternary surfactant type, such as dialkyl dimethyl ammonium chloride may be applied, as required, on the draw belt 48, and the formation wire 60 to avoid unwanted adherence of the web to these parts.

Example I A nonwoven elastic cloth with excellent drape and 4300 5 - 27 hand was made from poly(ethylene terephthalate), also referred to as PET, polyester and polyester type polyurethane filaments in the following manner.

A capillary rheometer (a piston and cylinder device conventionally used to test laminar fluid flow through a capillary tube under controlled conditions) — Mosdel A70, manufactured by the Instron Corporation, Canton, Massachusetts, was fitted with a steel die containing a short single cylindrical exit orifice having a diameter of 0.020 inches and a land length of 0.075 inches. The cylinder of this rheometer was heated to 270°C and filled with pellets of dried poly(ethylene teraphthalate) or PET polyester resin VFR 3810 supplied by Goodyear Tire and Rubber Company, Chemical Division.

VFR 3801 is a PET resin prepared by the catalyzed polymerization of ethylene glycol and terephthalic moiety well known in the art and having an intrinsic viscosity of about 0.62 as measured in 60% (wt) phenol/40% tetrachlorethane at 30%C at a concentration of approximately 4 grams per liter., The resin had been dried in a vacuum oven at 150°C and 30 inches Hg vacuum for 16 hours.

After drying, the resin was kept in sealed containers until heated. The rheometer piston was loaded to 100 psi pressure in the cylinder. At these conditions the rate of extrusion through the die was 0.18 grams per minute, the monofilament so formed was drawn vertically downwardly through ambient air and passed sinuously through a vertically aligned stack of three six inch diameter polished steel draw rolls placed about eight feet from and directly beneath the rheometer die. The surfaces of the rolls were about one-half inch apart and their axes were parallel and in vertical alignment. The filament path wrapped the first draw roll (the roll closest the die) about 85° and the second (the next roll) and third draw rolls (the roll farthest from the die) about 170.048.

I G 5 - 28 The filament was then drawn through an annular air aspirator — Transvector Model 501 supplied by the Vortec Corp., Cincinnati, Ohio. This aspirator comprises a plenum chamber for compressed air surrounding a ring shaped slot 0.002 inches wide leading about a 90° rounded turn to move an annular air jet by Coanda effect into a throat having an inlet opening of 0.038 inches and thence along a cylindrical cone frustrum downstream of the slot to maintain the supplied air as a laminar flow along said conical wall and produce an aspirating flow of air through the throat and an air amplification ratio therethrough of about 5.5. The aspirator was operated with compressed air at a pressure of 12 psi to produce a total air output flow through the aspirator of about 15 scfm.

This air flow through the aspirator forwarded the filament from the third draw roll and deposited it in random loops against a 30 x 36 mesh porous forming surface placed over a vacuum box operating at about one inch Eg >0 vacuum and drawing air through the forming surface at a mean velocity between 1500 and 2000 feet per minute.

The aspirator positively pulled the filament from the third draw roll and defined a specific focus or divergence point from which excursion and random movement of the filament contact point over the porous surface forming occured. The aspirator was spaced apart from the forming surface about two feet and the excursions of the filament contact point on the collection or forming surface covered an area about one-half foot in diameter, defining an excursion cone from the filament focus point subtending about 14 degrees at the apex.

The draw rolls were each operated at 1460 surface feet per minute to reduce the diameter of the melt spun monofilament to form a 3.6 denier filament and this fila> ment was deposited on a one foot square section of the 3 G G 5 - 29 forming surface as a uniform layer over the entire section by manually altering the direction of the aspirator stream in a manner such as to deposit substantially equal amounts of filament on each section of the screen.

In this manner a random laid unbonded web weighing 12 grams per square meter was built up on the forming surface.

The forming surface was a porous woven fabric of the type having generally equal height rounded knuckles and produced generally in accordance with the description embodied in U.S. Patent No. 3,473,576. The specific fabric of the forming surface was of plain weave, of approximately 12 mil diameter monofilaments. The forming fabric was initially sprayed with a release agent of the quarternary surfactant type, namely diaikyl dimethyl ammonium chloride.

Without removing the unbonded web so formed from the forming fabric the procedure was repeated using a polyester type polyurethane polymeric fiber forming elastomer, Texin 48OA, a polyester and glycol-based polyurethane supplied by Mobay Chemical Company, Pittsburgh, Pa. Texin 48OA is described in the pamphlet An Engineering Handbook for Texin Urethane Elastoplastic Materials published by Mobay Chemical Company in 1971 and can be prepared by means well known in the art as exemplified by U.S. Patent 2,871,218. The resin was dried at 100ψ and 30 inches Hg vacuum for four hours. During polyurethane deposition conditions were altered to a rheometer cylinder temperature of 200°C and a cylinder pressure of 760 psi resulting in an extrusion rate of 0.07 grams per minutes. The draw rolls were operated at a speed of 384 surface feet per minute to produce a 5.4 denier filament. The vacuum and aspirator pressures were unchanged, and the divergence cove angle was also substantially unchanged.

This filament was directed in a uniform pattern and formed on top of the polyester web previously formed until - 30 sous an additional vjeight of 12 grams per square meter was accumulated.

Finally, a second polyester web was formed over these two layers as in the first step at the same conditions as the first polyester layer and with the same polymer in the amount of an additional 12 grams per square meter.

This three layer unbonded web was then passed through a heated metal coated bonding roll nip at 10 feet per minute while still carried on the forming fabric. The roll pressure was 36 pounds per lineal inch. The roll contacting the web was heated to a surface temperature of 25O°F. The opposing roll contacting the forming fabric was unheated.

The bonding press used was a Hartig hot pressure roll bonding nip having an unheated steel cold roll of 8 inch diameter and 14 inch length covered with rubber, A scale Shore Durometer. The hot pressure roll was aluminium 7 1/4 inch diameter, 14 inch width and loaded ) with two 2 inch air cylinders. It was found that the cloth thus formed was securely bonded at the pressure points corresponding to the knuckles of the forming fabric.

The opposite edges of this cloth were then placed * in linear clamps and the cloth was stretched to 190% of its original length by pulling the clamps from 10 inches apart until they were 19 inches apart.

When released, it was found that this cloth was drawn back to nearly its original length by the elastomeric polyurethane filaments and that it was unusually supple for a random laid continuous filament bonded fabric, having the hand, finish and other characteristics generally of a lightweight conventional knit rayon jersey such as that conventionally used for lingerie. 3 0 6 5 - 31 Example II Another nonwoven elastic cloth with good opacity, smoothness, drape and hand was formed from three relatively non-elastic layers of polypropylene filaments and two layers of elastomeric polyurethane filaments.

The layers were separately formed as substantially unbonded webs in the equipment described in Example I and subsequently laminated and bonded, as follows; Rexene copolymer resin grade 44S3, an isotactic polypropylene resin containing about 3% ethylenepropylene elastomer resin and having a melt flow rate of 0.3 grams per minute at 23O°C and supplied by Rexene Polymer Corp, of Paramus, New Jersey was blended with 0.1% Ultramarine Blue and 4.0% Titanium Dioxide and extruded from the capillary rheometer at 215°C cylinder temperature and 220 psi piston pressure through the 0.020 inch orifice, 0.075 inch land length die at a flow rate of 0.11 grams per minute, the monofilament so formed was drawn through the S-wrap draw roll set operated at 660 surface feet per minute for each roll to a 4.9 denier filament and that 4.9 denier filament was forwarded with the annular aspirator to form a randomly dispersed web of approximately 7 grams per square meter on the forming surface. The vacuum box and aspirator were operated at the condition set forth in Example I above.

Throe such unbonded polypropylene filament webs were formed and layered alternately with 10 gram per square meter unbonded polyurethane filament webs made as described in Example I from Texin 48OA polyurethane melt spun at 0.08 grams per minute, at 199°C cylinder temperature and 1660 psi piston pressure; drawn at 256 feet per minute to form a 9 denier filament and forwarded to the forming surface with the annular aspirator and vacuum box operated as above. - 32 The five layered web was placed on the 30 x 36 mesh forming fabric of Example I and pressed in a heated platen press at 300°F and 210 psi for 2 seconds on one side. The web was removed from the fabric and pressed again with the mesh fabric on the opposite side of the web at the same conditions.

The resulting material had a basic weight of 41 grams per square meter, a tensile strength in all directions to rupture of 3.9 pounds per inch of web width and an elongation to rupture of 183%.

After the web had been prestretched to 150% of its original length, the material exhibited perfect elasticity at 25% elongation in subsequent cycles and had a tensile modulus of 1.5 pounds at 25% elongation.

While only two specific examples of elastic cloths made in accordance with this invention have been detailed hereinabove, there is no intent hereby to limit the claimed invention thereby. A wide range of fiber forming elastomeric and non-elastic polymers are well known to those skilled not only in the textile and yarn forming arts, but in the general chemical arts as well, and any fiber forming polymers, within the specific definitions herein set forth and within the express language of the appended claims as defined hereby are intended to be within the scope and breadth of the subjoined claims. Further, while in Example I the resultant cloth comprised approximately 33% elastomeric filaments and while in Example II the resultant cloth comprised approximately 50% elastomeric filaments, cloths in accordance with the present invention may be made comprising approximately 10-90% elastomer and in basis weights of from about 3.200% grams per square meter without departing from the scope hereof. 3 0 0 5 - 33 Example III Texin 48OA polyurethane resin is extruded from a die containing a single line of holes 0.015 in diameter spaced 0.150 apart along a distance of 30. This die is attached to a manifold, filter, static mixer and extruder as previously described with reference to the accompanying drawings and fed with polyurethane at 400°F at a rate of 100 grams/min. to form 200 filaments which are self-adhesive upon cooling to room temperature.

The polyester die is of exactly the same construction except that there are 3 lines of holes in the die spaced .150 apart but staggered to allow the production of 600 filaments spaced 0.050 inches apart when drawn into a common plane by the draw belt. This die is heated in 520°F and fed with dry GOODYEAR (Registered Trade Mark) POLYESTER RESIN VFR 3801 heated to 520°F at a rate of 100 gms/min.

The 60 x 78 mesh polyester monofilament draw fabric is driven at 1000 FPM and the draw fabric vacuum is 3 inches of water, the air jet device 56 is operated at 5 pounds per square inch, the eccentric drive to the shaft 106 is operated at 1000 cycles per minute, and the 40 x 36 mesh phosphor bronze forming wire 60 is driven nt J 5 fed. per minute. The phosphor bronze forming wire is made of ().010 inch diameter wire. The lorming wire is rolled to produce fiats 0.005 inch wide by 0.01.0 inch long on the knuckles. The shute wires are straight, and the warp wires are crimped around the shute wires.

A very uniformly formed elasticizable web weighing 57 grams/M of a width of about 30 inches may be formed in this manner of approximately 5 denier polyester filaments and 15 denier polyurethane filaments.

The web is stripped from the screen, the screen is heated and the hot screen and web are run through a DO S - 34 heated nip to produce spot bonds. Prior to bonding a fine mist of water is sprayed on the web at the rate (by weight) of 1/2 to 1, water to fabric. The nip is loaded to 60 pounds per linear inch. The screen is heated to 230°F and the opposing smooth roll is heated to 210°F. Pressure is applied in the spots in the range of 1000 to 5000 psi. The bond spots become heated to a temperature near 23O°F but the fibers between spots remain below 210°F which is insufficient to form bonds between the spots. Bonds measuring about .005 inches wide x .010 inches long are made at a density of 800 spots/square inch which includes less than 10% of the total fabric area. Shrinkage, which tends to occur during bonding, is prevented by restraining the web for a short time after bonding while maintaining it near the bonding temperature. The bonded web is elasticiz able by stretching followed by relaxation.

In Example III the parameters below are varied within the ranges given and satisfactory product is obtained.

Screen Temperature + 5°F Smooth Roll temperature + 5°F Nip loading + 20 pounds per linear inch Water Spray Rate + 25%.

Claims (33)

1. A non-woven fabric comprising two types of organic polymer fiber, one of which is elastomeric (as herein defined) and the other of which is elongatable but non-elastic (as herein defined), at least one of the types of fibers being dispersed to provide frequent random fiber crossings, at least the majority of which are autogeneously bonded with a bond strength sufficient to permit the non-elastic fibers to be stretched between the bonds with substantially no breakage of said bonds, the bonded crossings including bonds both within and between the fiber types.

2. A non-woven fabric according to claim 1 wherein each of the elastomeric and non-elastic fibers comprise filaments melt spun and mechanically drawn out to give filaments of 0.5-15 denier.

3. A non-woven fabric according to either of claims 1 and 2 wherein the elastomeric fiber comprises polyurethane.

4. A non-woven fabric according to any one of claims 1 to 3 wherein the non-elastic fiber comprises polyester.

5. A non-woven fabric according to any one of claims 1 to 3 wherein the non-elastic fiber comprises polypropylene.

6. A non-woven fabric according to any one of claims 1 to 5 comprising a substantially uniform layer having the non-elastic fibers generally uniformly dispersed and mixed therein.

7. A non-woven fabric according to any one of claims 1 to 5 wherein the elastomeric and the non-elastic fiber each define a generally distinct laminated layer.

8. A non-woven fabric according to claim 7 comprising a layer of elastomeric fibers disposed intermediate a pair of layers of non-elastic fibers.

9. A non-woven fabric according to any one of i claims 1 to 8 having a low modulus of elasticity in at least one direction which has been achieved by stretching the bonded fabric in the at least one direction followed by relaxation, so as to permanently elongate at least a proportion of the non-elastic fibers. .0 10. A non-woven fabric according to claim 9 wherein the stretching has been conducted uniformly in each of a plurality of directions. 11. A non-woven fabric according to any one of claims 1 to 10 wherein substantially all of the fiber .5 crossings are bonded. 12. A non-woven fabric according to any one of claims 1 to 11 wherein the bonded fiber crossings comprise a uniform pattern of spot bonds. 13. A non-woven fabric according to claim 12

10. Wherein the uniform spot bond pattern corresponds to the knuckle pattern of a porous woven forming fabric embossed therein by passage of the cloth through a heated bonding nip while carried on the forming fabric.

11. 14. A non-woven fabric according to claim 13 !5 wherein the spot bond pattern corresponds to the knuckle pattern of a generally square weave fabric.

12. 15. A non-woven fabric according to claim 13 wherein the Spot bond pattern corresponds to the knuckle pattern Of a generally twill weave fabric. 10

13. 16. A non-woven fabric according to claim 13 wherein said spot bond pattern corresponds to the knuckle pattern of a fabric woven of 12 mil diameter polyester 4 3 0 G 5 - 37 monofilaments as hereinbefore defined in Example 1.

14. 17. A non-woven fabric according to any one of claims 2 to 16 wherein at least one of the fiber types 5 comprises continuous filaments randomly looped and bunched into a coherent web and bonded by the application of heat and pressure thereto.

15. 18. Λ non-woven fabric according to claim 17 wherein each of the fiber types comprises continuous Jo Ti I.Hiienl.s randomly looped and embossed. 1'). Λ non-woven fabric according to any one of claims 1 to 18 wherein one of the fibre types is heavier than the other.

16. 20. A non-woven fabric according to any one of 15 claims 1 to 19 wherein a proportion of the fibers of each type form bonds at least two spaced apart locations therealong with fibers of the other type.

17. 21. A non-woven fabric according to claim 20 wherein substantially all of the fibers of each type 20 are bonded at at least two spaced apart positions thereof to fibers of the other type.

18. 22. A non-woven fabric according to any one of claims 1 to 21 wherein the elastomeric fibers comprise 10-90%, by weight, of the fabric. 25

19. 23. A non-woven fabric according to claim 22 wherein the elastomeric filaments comprise twenty to sixty-five percent, by weight, of the fabric.

20. 24. A non-woven fabric according to either one of claims 22 and 23 wherein the elastomeric filaments 30 comprise approximately 50%, by weight, of the fabric,

21. 25. A non-woven fabric according to any one of - 38 claims 1 to 24 wherein the fabric is porous and has a hasis weight of from 3-200 grams per square meter.

22. 26. A non-woven fabric according to claim 25 having a basis weight of from 10-150 grams per square meter.

23. 27. A non-woven fabric according to either one of claims 25 and 26 wherein the fabric has a basis weight of from 30 to 60 grams per square meter.

24. 28. A laid non-woven fabric according to claim 27 ) comprising from one third to two thirds by weight of the cloth of non-elastic melt spun, mechanically drawn polyethylene teraphthalate polyester filaments of approximately 3.6 denier and the remaining two thirds to one third by weight of cloth comprising elastomeric > melt spun, mechanically drawn polyester based polyurethane filaments of approximately 5.5 denier.

25. 29. A random laid non-woven fabric substantially as described with reference to Figures 1 to 3 of the accompanying drawings. )

26. 30. A method of producing a non-woven fabric, comprising the steps of substantially continuously forwarding synthetic organic elastomeric (as herein defined), and elongatable but non-elastic (as herein defined) fibers onto a porous forming surface, autoj genously bonding at least a proportion of the fiber crossings to provide a coherent bonded fabric web, and mechanically working the bonded web to elongate at least some of the fibers in at least one direction so that retraction of the elastomeric fibers provides looping 3 and bunching of the elongated non-elastic fibers to thereby develop a low modulus of elasticity in the at least one direction.

27. 31, A method according to claim 30 wherein the •13 0ο ο - 39 mechanical working comprises incremental stretching over a short span.

28. 32. A method according to either one of claims 30 and 31 wherein the step of continuously forwarding comprises the steps of simultaneously melt spinning separate streams of elastomeric, and elongatable but non-elastic, synthetic organic polymer filaments through separate spinnerette orifices of greater than 0.007 inch diameter, simultaneously mechanically drawing the streams of filaments from the orifices to reduce them to textile denier and projecting them at high speed to the forming surface.

29. 33. A method according to claim 32 wherein the melt spinning is through substantially linear spinnerettes to form planar, separate uniformly distributed streams of elastomeric, and elongatable but non-elastic, filaments and wherein the drawing step takes place without disturbing the stream alignment and distribution.

30. 34. A method according to either one of claims 32 and 33 wherein the separate streams of filaments are interleaved during forwarding to the forming surface.

31. 35. A method according to either one of claims 32 and 33 wherein the separate streams of filaments are separately forwarded to the forming surface to form a laminated layered structure.

32. 36. A method of producing a non-woven fabric in accordance with claim 1 substantially as described.

33. 37. A non-woven fabric when produced by the method of any one of claims 30 to 36.