US 3314840 A
Description (OCR text may contain errors)
April 1957 N. E. LLOYD ETAL 3,314,840
WOVEN FABRIC PROCESS AND APPARATUS FOR PRODUCING A NON 2 Sheets-Sheet 1 Filed Aug. 1, 1961 P 1967 N. E. LLOYD ETAL 3,314,840
PROCESS AND APPARATUS FOR PRODUCI NG A NON-WOVEN FABRIC Filed Aug. 1, 1961 2 Sheets-Sheet 2 United States Patent ce 3,3 14,840 Patented Apr. 18, 1967 ing and a great number of other products, staple fibers are generally employed as the raw material. fibers are synthetically produced by extrusion processes and then formed into of non-woven fabrics. The latter must then unbale the staple, open it, make it into a flat batting for addition of a plasticizer or binder, and finally subject it to a baking and calendering treatment so as to obtain the fabric in the final form thereof.
The cheapest grades of non-Wovens presently available on the market are usually made of natural staple fibers, principally, of course, for reasons of economy. Whereever a higher grade non-woven fabric is desired, i.e. one which is possessed of a number of special properties which are unattainable in a natural fiber non-woven, for example, greater toughness, elasticity, dimensional stability, etc., synthetic fibers are added. Synthetic fibers, however, are relatively expensive to produce, and thus their use as components of the non-Wovens considerably increases the cost thereof, a result which is even more evident if the non-Wovens are produced entirely from synthetic staple fibers or continuous filaments.
It is, therefore, an important object of the present invention to provide novel and highly efficient processes of and apparatus for producing non-woven fabrics from the known non-woven production techniques.
It is another object of the present invention to provide processes of an apparatus for producing high grade nonwovens from continuous filament synthetic fibers in a It is also an object of the present invention to provide processes and apparatus as aforesaid by means of which the production of the non-woven fabrics can be made a direct adjunct of the filament extrusion operation at the metier so as to eliminate all need for the heretofore unavoidable handling of the filaments after their extrusion and prior to the formation of the non-woven fabrics.
More specifically, the objectives of the present invention are attained by the substantially horizontal, movable take-up surface onto which the synthetic filaments are to be deposited. The
extent in a completely random manner prior to the depositing of the filaments on to the take-up surface.
-In accordance with one aspect of the present invention, the take-up surface is constituted by an endless wire mesh screen belt the width of which may range from about 10 to 260 inches and which is supported by and driven over a pair of cylindrical rolls disposed at the points of reversal of the belt movement. rolls is preferably a driven roll and is connected to a which may If desired, brake means may to bring the each indexing or In lieu of the kicking of the belt.
aforesaid indexing mechanisms, it is driven jogging motor ever, have to be to prevent the jogging motor from causing any coasting of the belt at the end of each incremental stroke thereof.
direction of movement of said toward the surface of the take-up belt. It is contempresent invention that the air jet may or beside the mass of filaments issuing from the extrusion jet, as seen in the direction of travel of the said belt. The extrusion jet and its associated air jet are preferably supported for vertical adjustment on a carriage or slide structure arranged for horizontal movement transverse to the direction of movement of the belt. The carriage is mounted on a rail or slide bar system constituting a part of a suitbelt drive mechanism only when the jet-m0ving carriage is stationary at the reversal points of the movement thereof.
More than one set of one extrusion jet and one air jet may, of course,
event it is necessary, however, that the stream of filamentagitating air be coextensive in width with the take-up belt, as by being blown through an elongated slot, so that the v formate,
filaments are subjected to the air stream at all times irrespective of the positions of the extrusion jet or jets.
Examples of filament forming materials which can be used in implementing the principles of the present invention are organic derivatives of cellulose such as ethers and/ or esters thereof, e. g. ethyl cellulose, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate, cellulose acetate propionate, cellulose acetate, butyrate, etc., which esters may be ripened so as to modify their solubility characteristics or may be unripened, i.e. containing fewer than about 0.29 free hydroxyl groups per anhydroglucose unit, such as cellulose triacetate. While other filament forming materials such as polyamides, e.g. nylon 6 or 66, linear polyesters such as polyethylene terephthalate, acrylonitrile polymers and copolymers, olefinic polymers such as polyethylene, polypropyene, polyvinyl chloride, polyvinyl acetate, polyvinyl chloride-vinyl acetate, polyvinylidene chloride, and the like, can be employed, organic acid esters of cellulose, such as cellulose acetate, are preferred and these are advantageously extruded as a solution into a heated evaporative atmosphere.
The mass of filament forming material in is generally heated to temperatures ranging from 50 to 150 and is extruded from the spinnerette, which it may reach via any suitable conduit arrangement such as a flexible, high pressure, brass hose operated in conjunction with a 90 swivel joint, at pressures ranging from 250 to 2,000 p.s.i.g. The filaments issuing from the face of the spinnerette or extrusion jet are preferably moving at velocities ranging from 500 to 3,500 meters per minute. The air issuing from the air jet is preferably maintained under pressures ranging from 3 to p.s.i.g. From 2 to 20 cubic feet per minute of free air, i.e. air at standard conditions of 70 F. and atmospheric pressure, are required for proper operation of each set of one extrusion jet and one air jet.
As a consequence of the operation of the belt and associated extrusion and air jets under the stated conditions, there is formed on the belt a continuous body or matted web of randomly convoluted, intersecting and interlaced continuous filaments, the web being composed of a plurality of parallel sections which overlap one another by virtue of the fact that each of these sections as it is laid onto the belt is moved away from the region of the spinnerette by an amount less than the width of each section of filaments deposited on the belt. As will be clear to those skilled in the art, the filaments extruded from the spinnerette are still in a semi-plastic condition when they reach the belt, and they will, therefore, tend to coalesce and adhere to one another at their points of intersection or contact. The entire web thus becomes a coherent fabric entity having considerable mechanical strength. It will be understood that by suitably varying the lengths of the increments of movement of the belt, the individual filament layers or sections deposited on the belt by the spinnerette can be overlapped to any desired greater or lesser extent so as to bring about the formation of multi-layer non-woven fabrics of correspondingly different predetermined thicknesses.
The entire web-forming apparatus, comprising the spinnerette or spinnerettes constituting the filament extruding means, the air jets or jets constituting the filament agitating means, and the belt constituting the take-up means are usually enclosed in a suitable housing or cabinet, the atmosphere and temperature conditions in the interior of which may be controlled in accordance with the composition of the filamentary material being extruded and with the manner in which it is extruded into filament form, i.e. by means of a wet, dry, or melt spinning process. Thus, if the filaments are formed from a dope comprising a solution of cellulose acetate (or the like) in acetone there are provided in the cabinet, preferably between the upper and lower reaches of the take-up belt, finned copped tube heating coils through which saturated steam at a pressure the metier of about 150 p.s.i.g. is coursed to maintain the air or atmosphere in the cabinet at a temperature between about and 300 F. This air is preferably introduced into the cabinet by means of compressors or small blowers and may, if desired, be preheated before entering the cabi net. In this manner, it is possible to elfect a controlled rate of evaporation and eduction of the acetone or other residual solvents from the solidifying non-woven mat of filaments. Suitable means for exhausting the acetoneladen air from the cabinet are also provided. On the other hand, if the filaments are formed from a melt of the filament forming material, the provision of the heating coils and even of the cabinet itself may be dispensed with.
Other objects, characteristics and advantages of the present invention will be more clearly realized from the following description thereof when read in conjunction with the accompanying drawings, in which:
FIG. 1 is a diagrammatic and schematic side elevational view of one embodiment of an apparatus for producing non-Wovens in accordance with the present invention;
FIG. 2 is a top plan view of the apparatus shown in FIG. 1 and illustrates in addition the drive means for the extrusion jet and for the take-up belt;
FIG. 3 is a fragmentary view, on an enlarged scale, of the structure shown in FIG. 1 and illustrates in detail but schematically the formation and the stnucture of the fabric;
FIGS. 4, 5 and 6 are schematic illustrations of some possible modifications of the relationship between the extrusion and air jets of the apparatus shown in FIGS. 1 and 2; and
FIG. 7 is a view similar to FIG. 6 and illustrates a further modification of the apparatus.
Referring now more particularly to FIGS. 1 and 2 of the drawings, it will be seen that the apparatus according to the present invention essentially comprises filament forming or extruding means 8, filament agitating means 9, and take-up means 10 on which the filaments are deposited to form the desired non-woven fabric. The entire system is arranged in a cabinet or housing (not shown).
The take-up means 10 preferably comprises an endless belt 11 made of wire mesh screen and supported at its opposite ends by a pair of rolls or drums 12 and 12a. The upper reach 11a of the belt 11 passes over one or more idler rolls 13 positioned bet-ween the rolls 12 and 12a which enables the upper reach of the belt to be kept substantially horizontal during its travel from the roll 12a to the roll 12. The rolls 12, 12a and 13 are all journaled in suitable bearings (not shown) supported on a rigid steel framework (not shown) arranged in the aforesaid cabinet or housing.
Connected to the axle 12 of the roll 12 in any desired manner, not explicitly illustrated herein, is a unidirec tional intermittent drive or indexing mechanism 14 which may be a ratchet and pawl device, a Geneva movement, a pneumatically operated kicker or the like capable of effecting an intermittent or step by step rotation of the roll 12 in a clockwise direction as seen in FIG. 1. The actuating means for the indexing mechanism 14, which will hereinafter be referred to as the kicker, may be of any suitable type and either manually or automatically operable. Merely by way of example, inthe illustrated embodiment of the invention, this actuating means comprises a single-acting pneumatic cylinder 15 having a reciprocal piston 16 therein which is drivingly connected with the kicker 14 by means of a piston rod 17 and is biased toward its retracted or inactive position by a compression spring 18. The space 19 of the cylinder 15 behind the piston 16 is connected with one port 20 of a solenoidoperated three-way valve 21 which has a second port 22 opening to the atmosphere and a third port 23 connected with a source 2.4 of air under pressure. It will be understood, therefore, that each time the solenoid valve 21 is actuated to establish communication between the pressure source 24 and the cylinder space 19, the piston 16 is disand permit retraction of the piston shown), a positioned above one end of the upper reach 11a of the belt 11 and adjacent the roll 12a. In the illustrated example of the apparatus, the spinnerette 25 has a cup portion 25' terminating in a circular orifice plate 26 which is about 1% inches in diameter and has formed therein a multiplicity of exbetween about 0.020 mm. all the openings are substantially circular, but they may have other shapes. The spinnerette or extrusion jet 25 is connected via a flexible conduit 27, e.g. a high pressure brass hose available commercially under the trademark Penilex, with the interior of the metier (not shown). The spinnerette 25 or slide bar system 30 extending transversely to the longitudinal dimension of the belt 11 and substantially coextensive in length with the roll or drum 12a. Two pneumatically operated limit switches 30a and 30b are arranged at the opposite ends of the rail 30. The carriage 29 is provided in its surface facing away from the arm 28 with a groove 31 into which extends slidably an elongated pin 32 carried by one of the links of an endless sprocket chain 33' supported at its opposite ends by a pair of sprockets 34 and 35. The axle of the sprocket 34 is connected to a suitable speed control mechanism, such as an adjustable gear reducer 36 which is connected to a drive motor 37.
The carriage 29 in addition source of compressed air (not shown).
As indicated by the double-headed arrows in FIG. 1, both the spinnerette 25 and carriage 29 or by shifting the jets 25 and 39 relative to their respective supports 28 and 38. Moreover, means may be provided for effecting angular adjustments of the jets so as to vary their inclinations relative to one another and relative to the plane of the upper reach 11a of the take-up belt 11. By way of illustration, in FIGS. 1 and 2, for example, the face of the orifice plate 26 of the spinnerette 25 is horizontal, and the filament streams F extruded through the plate 26 thus travel toward the belt 11 at an angle of about 90 to the direction of travel of the belt (arrow A), while the air jet 39 blows against the filaments a stream of compressed air in a direction oriented at an angle of 90 relative to he direction of movement of the filaments. As shown in FIGS. 4 and 5, according to further aspects of the present invention vertically descending filaments F may be subjected to the agitating action of an air stream directed at an acute angle to their direc tion of movement toward the belt, or filaments traveling at an acute angle, for example as small as 30 or less, relative to the direction of movement of the belt may where the orifice may be attained by other relative orientations of the air and extrusion jets, e.g. Where neither of the latter is in a horizontal or vertical position. This holds true also take-up belt, before assuming a downward trajectory toward the upper belt reach llla.
belt and to vary the point of incidence of the air stream against the said filaments before the latter reach the take-up belt.
In the hereinbefore described embodiments of the apparatus according to the present invention, it will be noted that the air stream impinges against the filament direction of movement of the belt 11. The carriage 2-9 and its associated elements would then be positioned to the right of the extrusion jet rather than as shown in FIG.
the spray is directed onto the freshly laid non-woven mat (still to be described), the nozzle 41 may be supported by the carriage 29 for movement therewith. the spray head or nozzle 41, ment stream as shown in FIG. 7, is used with an air jet 39 positioned in front of the filament stream as shown in FIGS. 1 to 5, however, steps must be taken to ensure that the air stream does not disturb the plasticizer or solvent spray. This before the same Here, too, the air jet and spray head must be traversed out of phase with one another. It is to be understood, of course, that the extruded toward the belt 11 through the orifice plate 26 of the extrusion jet which is disposed at a predetermined distance of from 2 to 40 inches above the belt, all of these filaments being disposed essentially parallel to one another, untwisted, and still somewhat plastic, by virtue of Containing residual solvent if spun from a solution of the filament forming material or by virtue of being incompletely solidified if spun from a melt of the filament forming material. At some preselected point between the face of the orifice plate and the upper reach 11a of the take-up belt 11, e.g. from 1 to 35 inches above the latter, the downwardly streaming array of filaments F is subjected to the influence of a stream of high pressure air flowing transversely to the path of travel of the filaments at an angle ranging from 30 degrees or less to 90 degrees, and preferably at an angle ranging from 45 to 90 degrees, to the direction of movement of the stream or array of filaments. The latter are, thus, violently agitated and whipped about in a completely random manner and are, accordingly, substantially deformed out of their initial linear state as well as randomly entangled and interlaced with one another.
The resultant non-oriented mass of randomly convoluted and intersecting filaments, upon reaching the take-up belt 11, is deposited on the upper reach 110 of the latter in the for-m of a relatively narrow entangled layer or web extending across the belt due to the fact that the extrusion jet 25 is traversed over the belt as the filaments are formed. The first such layer in any sequence is designated L1 in FIG. 3. As this layer rests on the belt 11, the still plastic filaments tend to coalesce and become bonded to one another at their points of contact. Where necessary, as in the case of the filaments being spun from a solution of cellulose acetate in acetone, for example, the rate of evaporation of the solvent may be predetermined by controlling the temperature and atmospheric conditions existing within the drying cabinet (not shown) which enclosed the belt 11, to which end a system of finned copper tube heating coils 42 may be arranged within the said cabinet between the upper and lower reaches 11a and 11b of the take-up belt 11.
As the carriage 29 arrives at the other end (the lower one in FIG. 2) of the rail 3t), it actuates the switch 301) which causes the solenoid valve 21 to be operated so as to permit actuation of the kicker 14 through the intermediary of the cylinder 15 and the piston 1617. The belt 11 is thus shifted a predetermined distance in the direction of the arrow A, preferably less than the width of the layer Lll. Concurrently therewith, the pin 32 reaches and moves around the sprocket 35, whereby it is shifted to the lower reach of the chain 33. During the passage of the pin 32 about the said sprocket, therefore, the pin slides downwardly along the vertical slot 31 of the carriage 29 so that the latter remains essentially stationary.
The pin 32 now begins to move in the opposite direction, i.e. toward the sprocket 34, with the lower reach of the chain 33. The carriage 29 and the jets 25 and 39 are thus traversed back to their starting positions, which results in a second layer of filaments being deposited on the upper reach 11a of the take-up belt. This layer is designated L-Z in FIG. 3, and it will be seen that a portion of this layer overlaps and rests on the first layer L1, to an extent determined by the magnitude of the incremental movement of the belt relative to the width of the layer. As the still plastic filaments of which the layer L-2 is formed solidify, they will not only coalesce with one another at their points of contact, but will also adhere and become bonded to the filaments at the top surface of the previously formed layer L-l, which may also still be somewhat plastic, i.e. not fully solidified, so as to make the two layers into one coherent entity.
When the pin 32 reaches the sprocket 34, the carriage 29 actuates the limit switch 36a which causes the kicker 14 to be actuated again to advance the belt another predetermined distance. While this is taking place, the pin is traveling about the sprocket 34 and upwardly along the slot 31 in the carriage 29, so that the latter is essentially stationary while the belt is moving.
The traverses of the extrusion and air jets as hereinbefore described are thereafter repeated again and again, with each traverse of the extrusion jet 25 and air jet 39 forming another layer of matted and tangled filaments on the stationary take-up belt, as indicated by L3, L-4 and L-S in FIG. 3, and with the successive traverses of the jets alternating with incremental advances of the take-up belt so as to ensure that each layer overlaps at least a part of the preceding layer and possibly also a part of the second preceding layer, as shown in FIG. 3.
In this manner, there is formed continuously and as a direct adjunct to the extrusion of the filaments F from the metier a non-woven fabric N which can be taken up from the end of the belt 11 overlying the roll 12 onto a beam or into a bale or package for storage and/ or shipment. Such a fabric, due to the bonding of a great number of randomly oriented continuous filaments to one another at their points of intersection and contact, is possessed of considerable mechanical strength and dimensional stability in any direction of the fabric. By means of the process and apparatus according to the present invention, furthermore, it is possible to provide the nonwoven fabrics with a great variety of special physical properties such as weight per unit length, hand, stiffness, filtration power, insulating value, resiliency, draping ability, etc., to any desired and predetermined degree. Stiffness, for example, can be attained by spraying a solvent or plasticizer such as acetone or dimethyl ethyl phthalate and trichloroethyl phosphate against the front of the agitated filament stream before the same is deposited on the take-up belt or against each layer L1, L2, etc. after it is formed on the belt. Merely by way of illustration, continuous filament non-Wovens of the herein disclosed types may be advantageously employed as filters for air heating and conditioning systems, inner shoe soles and shoe interliners, lamp shades, upholstery backing, filters for milk, beer, oil and other liquid processing systems, window dressings, insulation, wall coverings, rug backing, quilting, casket liners, acoustical curtains, pennants and banners, decorative wrapping materials, suit and dress materials, and the like. Many of these prod,- ucts can now, by following the teachings of the present invention, be manufactured so as to be priced competitively with comparable products heretofore manufactured from cheaper materials than continuous filament synthetic fibers.
It will be understood that the process and apparatus as herein disclosed are susceptible to being modified in a number of ways, depending on the particular desired physical or other characteristics, e.g. resistance to heat, water or chemicals, of the ultimate non-woven fabric. Moreover, the air stream may impinge on the filaments from the side rather than from the front or rear as shown in the drawings. It is possible to employ more than one extrusion jet, in which case these jets, each associated with a respective air jet, may be traversed across the takeup belt either in or out of phase with one another so as to produce layers of matted filaments which overlap one another both longitudinally and transversely of the fabric. Also, successive layers of the fabric may be formed by different jets traversed across the belt in alternating sequences. These arrangements lend themselves very readily to the creation of special decorative patterns and designs, as where the extrusion solutions or melts are differently pigment-dyed. It is further possible, within the contemplation of the present invention, to utilize a continuous rather than intermittent belt movement. To this end, however, the belt speed must be relatively small as compared to the extrusion jet traverse speed, and at the same time one or more pairs of extrusion jets 25 must one extrusion jet.
The following example will serve to illustrate the principles of the present invention more clearly.
Example trusion jet is located in a drying cabinet, to which air at a temperature of approximately 200 F. is supplied, at a distance of 14.5 inches above one end of an endless wire mesh take-up belt and oriented to extrude the filatake-up belt. deposited on the belt in transverse layers 54 inches long, and each layer overlaps the preceding layer to the extent of about 80% of the Width of the preceding layer. The coherent fabric formed in this manner is, after trimming, 50 inches wide and inch thick and weighs 4.5 ounces per yard. It has exceptionally good lateral and longitudinal uniformity and stability, and is found to have a smooth hand and high resiliency as well as high filtration power. Such a fabric is particularly suited for use in the manufacture of Christmas tree snow batting, when calendered lightly, as backing for carpeting and furniture upholstery materials.
By Way of resume, therefore, in accordance with the broadest aspects of the present invention the mass of filaair is directed at these filaments at a point spaced from the take-up surface so as to agitate the filaments and cause them to be whipped about and entangled into contact with one another at randomly spaced points prior to their arrival at the take-up surface. Theastream of still plastic filaments, while being subjected to the action of the stream of pressurized air, is reciprocally traversed across the take-up surface which many variations may be made in the invention without departing from the spirit thereof.
Having described our invention, What we desire to secure by Letters Patent is:
1. The process of producing a non-woven fabric, comprising the steps of extrudmg a mass of filament forming material in liquid phase downwardly toward a movable, substantially horizontal take-up surface through a p prior to their arrival at said take-up surface, traversing the stream of filaments while still in plastic condition, said stream of filaments being associated with said stream of air back and forth across said take-up surface While the latter is stationary, and advancing said take-up sur- 1, wherein the initial path along which said filaments are extruded is oriented at an angle movement of said take-up surface, and said stream of air is oriented at an angle ranging from about 30 to degrees to the general path of movement of said filaments toward said take-up surface.
3. The process of claim 2, wherein said stream of air ceding layer.
10. The process of claim 9, wherein said distance is sufiiciently short relative to the width of each of said layers that each layer overlaps parts of at least the next two preceding layers.
11. The process of claim 1, wherein said filament forming material is a solution of cellulose acetate in acetone and is extruded at a pressure ranging from about 250 11 to 2,000 p.s.i.g. and at a temperature ranging from about 50 to 150 C.
12. The process of claim 11, wherein the pressure of said stream of air impinging against said elements varies from 3 to 25 p.s.i.g.
13. The process of producing a prising the steps of extruding a liquid solution of cellulose acetate in acetone downwardly and along a path the length of which ranges from about 2 to 40 inches toward a porous, horizontal, movable take-up surface to form a stream of substantially parallel continuous filaments oriented at an angle ranging from about 30 to 90 degrees to the horizontal, directing a stream of air under pressure at the still plastic filaments at an angle ranging from about 30 to 90 degrees relative to the direction of movement of said filaments and at a point the distance of which from said take-up surface ranges from about 1 to 35 inches thereby to agitate said stream of filaments and cause the latter to be whipped about and entangled into contact with one another at randomly spaced points prior to their coming to rest on said take-up surface, traversing said stream of filaments while the same are still in plastic condition, said stream of filaments being associated with said stream of air back and forth across said take-up surface at velocities varying from about 16 to 150 feet per minute, providing an evaporative atmosphere about said take-up surface under conditions sufficient to cause evaporation of said acetone from said filaments, maintaining said take-up surface stationary during said traverses of said filaments thereacross, and advancing said take-up surface in a direction perpendicular to the direction of traverse of said filaments only when the latter each the reversal points of their traversing be deposited in their entangled state on said take-up surface in the form of an elongated matted web of predetermined thickness composed of a plurality of substantially parallel, overlapping, laterally contiguous layers and having a coherent structure in all directions resulting from the coalescence of said filaments at said points of contact.
14. The process of claim 13, further comprising the step of spraying acetone against said layers from above substantially as the same are formed on said take-up surface to fuse some of said filaments making up said layers and thus impart a predetermined degree of stiffness to the ultimate non-woven fabric.
15. The process of claim 13, further comprising the step of spraying acetone against said stream of filaments in their entangled condition from in front of said filaments as seen in the direction of movement of said takeup surface and during the traversing of said filaments across said take-up surface, thereby to engender a fusion of those of said filaments constituting the bottoms of said layers, whereby the ultimate non-woven fabric has a relatively stiff bottom surface.
16. Apparatus for producing a non-waven fabric, comprising an endless movable belt the upper reach of which defines a take-up surface, an extrusion jet provided with an orifice plate for extruding a stream of substantially parallel filaments toward said take-up surface adjacent one end of said belt, an air jet for directing a stream of air under pressure at the still plastic filaments at a point intermediate said orifice plate and said upper reach of said belt to agitate said stream of filaments and cause them to be whipped about and entangled into contact with one another at randomly spaced points prior to their arrival at said belt, support means for said extrusion jet and said air jet, first drive means operatively connected with said belt for advancing the latter intermittent- 1y, second drive means for traversing said support means non-woven fabric, comand thus the agitated filaments back and forth across said belt, and means responsive to arrival of said support means at the reversal points of the traverse path thereof for actuating said first drive means only upon said support means being effectively stationary, whereby said filaments are deposited in their entangled state on said take-up surface of said belt in the form of an elongated matted web composed of a plurality of substantially parallel, overlapping, laterally continguous layers and having a coherent structure in all directions resulting from the coalescence of said filaments at said points of contact.
17. Apparatus according to claim 16, further comprising a spray head positioned above said belt for directing against sa'd layers, substantially as the same are formed, a plasticizer for fusing some of said filaments making up said layers so as to impart a pre-determined degree of stiffness to the ultimate non-woven fabric.
18. Apparatus according to claim 16, further comprising a spray head carried by said support means for directing against said entangled filaments at the front surface thereof, as viewed in the direction of movement of said upper reach of said belt, a plasticizer for fusing those of said filaments at said rear surface so as to impart a predetermined degree of stiffness to the ultimate nonwoven fabric.
19. Apparatus according to claim 16, further comprising brake means operatively connected with said belt for ensuring a substantially instantaneous stopping thereof upon deactuation of said drive means.
20. Apparatus according to claim 16, said support means being provided with means for adjusting said jets vertically and angularly relative to said belt and relative to one another, to permit said orifice plate to be disposed at a distance ranging from 2 to 40 inches above said takeup surface and to orient said stream of filaments at the place of extrusion at an angle ranging from 0 to degrees relative to the direction of movement of said belt, and to permit said air stream to impinge against said filaments at a distance ranging from 1 to 35 inches above said take-up surface.
21. Apparatus according to claim 20, said air jet being disposed behind said stream of filaments as viewed in the direction of movment of said upper reach of said belt.
22. Apparatus according to claim 20, said air jet being disposed in front of said stream of filaments as viewed in the direction of movement of said upper reach of said belt.
23. Apparatus according to claim 20, said first drive means being preset to move said belt and thus said takeup surface, at each actuation of said first drive means, a distance less than the width of each of said layers deposited on said take-up surface.
24. Apparatus according to claim 20, further comprising a cabinet enclosing said belt, said extrusion jet and said air jet and providing an atmosphere for drying and solidifying said filaments in said layers.
References Cited by the Examiner UNITED STATES PATENTS EARL M. BERGERT, Primary Examiner.
D. J. DRUMMOND, P. R. WYLIE, I. MATTHEWS,
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,314 ,840 A i 1 19 7 Neil E Lloyd et a1 It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below Column 2, line 41, for "impringes" read impinges column 5, line 68, for "he" read the column 10, line 54, after "at" insert an column 11, line 33, for "each" read reach line 56, for "non-waven" read non-woven Signed and sealed this 14th day of November 1967.
EDWARD J. BRENNEE Commissioner of Patents Edward M. Fletcher, Jr.