US2687363A

US2687363A - Method and apparatus for the production of filaments and nonwoven fabrics

Info

Publication number: US2687363A
Application number: US185240A
Authority: US
Inventors: Fred W Manning
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-09-16
Filing date: 1950-09-16
Publication date: 1954-08-24
Anticipated expiration: 1971-08-24

Description

Aug. 24, 1954 F. w. MANNING METHOD AND APPARATUS FOR THE PRODUCTION OF FILAMENTS AND NONWOVEN FABRICS 2 Sheets-Sheet 1 Filed Sept. 16, 1950 1 2 .4 Q 74 w H N E, .9. p 8% m N w F. W. MANNING METHOD AND APPARATUS FOR THE PRODUCTION OF FILAMENTS AND NONWOVEN FABRICS 2 Sheets-Sheet 2 INVENTOR I Aug. 24, 1954 Filed Sept. 16, 1950 r P: Q a a Id. H

Patented Aug. 24, 1954 METHOD AND APPARATUS FOR THE PRO- DUCTION IOF FILAME FABRICS NTS AND NONW'OVEN FredW. Manning, Palo Alto, Calif. Application September 16, 1950, Serial N0. 185,240 34 Claims. (Cl. 154-101) My invention relates particularly to improved methods and apparatus for producing stretchoriented filaments and fabrics made therefrom. This application is a continuation-impart of my copending applications: Serial Nos. 663,302 and 702,205, filed April 19, 1946, and October 9, 1946, respectively; and subsequently issued as patents, Nos. 2,522,526 and 2,522,527, respectively; and ap plication Serial No. 742,247, filed April 18, 1947, now abandoned in favor of the present application. Other modifications of the present invention are disclosed in my U. S. applications, Serial Nos. 384,882; 414,717; 425,374, filed October 8, 1953; March 8, 1954; and April 26, 1954, respectively.

Stretch-orientation of a filament ordinarily commences at the moment a filament can be sufficiently tensioned to assume a substantially straight line between horizontal holding and pulling means without the aid of support between the two said means. This may be at the moment it leaves the spinneret, and for sometime thereafter the filament may continue to be in a plastic and an adhesive condition, as indicated by the distance usually maintained between the spinneret and first wind-up bobbin to prevent sticking of the adjacent filaments; and so long as a filament is maintained in this plastic and adhesive condition, or is attached to a source of supply in this plastic and adhesive condition, the filament or source of supply may be drawn out indefinitely. However, once the filament has become set, additional stretching will usually bring it to its initial point of elasticity, and from there until its elastic limit has been reached it may be truly elastic, returning to its initial point of elasticity when the tension has been removed.

Smooth surface solid filaments cannot ordinarily be stretch-oriented and propelled simulta neously by force of a fiuid stream. Therefore, prior practice has been either to deposit a web of unoriented filaments on a backing which had strength, or to build up a coating of comparatively great strength on the web. The latter method resulted in an impervious web which was often undesirable, and either way was costly, especially when the spinning and spraying solutions contained large amounts of expensive, explosive, and non-recoverable solvents. The result was that the strength of a finished covering produced by filaments propelled and deposited by means of a fiuid stream always existed in the backing, or the coating, rather than in the fabric.

As distinguished from such prior practice, it is an object of my invention to provide a methiii . poses; adsorptive solids, such as carbon, silica od whereby a fibre-forming material is attached to pulling solids, the material disrupted or attenuated into filaments which adhere to the solids, and the solids propelled by an elastic or liquid fluid stream so as to exert a greater stretching force on the filaments than can be exerted by the fluid without their aid. The propulsion fluid may then be used to deposit the stretch-oriented filaments either in a plastic and adhesive condition, ori'n a set and adhesive condition, or the filaments may be made adhesive after deposition to cause them to adhere at their intersections to form an integral fabric.

The proposed fabric will require neither backing nor coating for its strength, and may be made impervious or otherwise treated by a coating of the usual thermoplastics or thermosetting materials, such as a copolymer of vinyl chloride and vinyl acetate, or a phenol formaldehyde resin; or it may be coated and impregnated by: water repellents, such as a silicone vapor; fire retardants, such as ammonium sulfamate; wetting agents, such. as dioctyl sodium sulfosuccinate; etc. Other objects of my invention will become apparent from the following description.

In accordance with my invention, the fibreforming material used for the production of the filaments and integral fabrics may be organic or inorganic, and thermoplastic or thermosetting, such as the usual plastics extruded into filaments, films, and foils. Some of the most common of these are: polymeric amides, vinylidene chloride, polyethylene, glass, quartz, etc, spun from a molten state; cellulose-acetate, vinyl-chlorideacetate resins, etc., spun from an acetone solution; protein-base materials, petroleum derivatives, etc. All such materials can also be sprayed in droplets or otherwise used for coating and impregnation purposes, and there are many materials, such as enamels, paints, etc, which can be used for such purposes but cannot be spun into filaments.

Some of the pulling solids which can be used for stretch-orienting filaments and may be in corporated and bonded thereafter by them into integral fabrics are: protein fibres, such as shredded scrap leather, used in the'manufacture of leather goods; mineral solids, such as as bestos, vermiculite, perlite, etc, for fireproof insulating coverings; vegetable fibres, such as cotton, wood, yucca, sisal, etc, for packaging purgel, etc., for adsorbing odors, moisture, etc. also for packaging purposes; purifying agents, such :as carbon, diatomaceous earth, fullers earth, etc,

for filter fabrics; abrasives, such as silica, carbide, corundum, etc., for sanding belts and safety walks; stretch-oriented filaments having a higher softening point than the filaments to be stretchoriented and required to give strength, warmth or beauty to the finished fabric; fertilizer pellets, which may or may not have seeds encased therein, for fabrics to be sprayed over freshly seeded ground, or ground to be seeded and protected thereby.

Other types of pulling solids that may be separated from the filaments subsequent to their stretching are: evaporative, such as Dry Ice pellets made from carbon dioxide, which may or may not have fibrous materials incorporated within them for adherence to a filament-forming plastic; plastic solids, such as polyvinyl alcohol pellets, which may be washed from the fabric by a water solvent; frangible solids, such as starch,

glucose, diatomaceous earth, which may be ren duced to powder by impact or explosion and the powder removed by an air blast or suction; polytetrafluoroethylene pellets, which become nonadherent on quenching; sodium alginate, and other natural or man-made fibres which can be removed from a finished fabric by means of an alkali or other solvent wash; air bubbles made from dioctyl sodium sulfosuccinate, glycerine and water, which explode under reduced pressure after passing out of the gun and/or ejector barrel; or the bubbles may be incorporated in the filaments in the usual manner and left therein in the manufacture of life preservers, air cushions, etc.

All such solids may be used for pulling and attenuating fibre-forming plastics into stretchoriented filaments; all such solids may be propelled from a rotor in a constant stream and for substantial distances, as from five to twenty feet, under a fluid pressure from 25 to 150 pounds per square inch, or by centrifugal action.

Certain pulling solids, such as vermiculite, perlite, etc., may contain free moisture and/or water of constitution and when subjected to heat and pressure and the latter suddenly released, will result in the free moisture or water of constitution being transformed into steam, thereby exploding, expanding, or exfoliating the solids and disrupting the contacting plastic into adherent filaments. Other solids, which may or may not contain free moisture and water of constitution, may be mixed, coated, or impregnated with: elastic fluids, such as steam; liquid fluids, such as water; or solids, such as carbon. These fluids and solids, after being subjected to pressure, thermal or chemical treatment to produce pressure, and the pressure suddenly released, will result in the sudden expansicn or explosion of an elastic fluid, thereby disrupting the solids which they contact, impregnate, or with which they are mixed. The filaments can then be stretch-oriented by the pulling force of the exploded particles conveyed by their explosion gases or other conveying fluids; or the filaments may be stretch oriented by the propulsion of the solids before explosion takes place, and the exploding, expanding, or exfoliating of the solids utilized as a means of separating the solids from the filaments.

The fibre-forming materials and pulling solids may be conveyed on adiacent primary and secondary rotors, respectively, and the solids brought into adhesive contact by the converging arcuate paths of the rotor peripheries. The said materials can then be positively drawn into filaments by the diverging arcuate paths of the peripheries.

and the filaments subjected to a second and third stretching by the propulsion of the solids from the secondary rotor during and subsequent, respectively, to the adherence of the filaments to the primary rotor. The setting of the filaments may be accomplished during the stretching periods, or after deposition, and as a result of cooling or quenching for a fibre-forming, heat reactive plastic, evaporation of solvent for a fibre-- forming plastic in solution, or simply by stretching as in the case of certain cellulosic derivatives.

The fibre-forming plastic may be charged onto the periphery of a primary rotor in discrete portions uniformly spaced to contact discrete pulling solids similarly spaced on, or uniformly distributed over, a' secondary rotor; the plastic may be charged onto the periphery of a primary rotor as a film coating to contact discrete solids uniformly spaced on, or distributed over, a secondary rotor; the use of pulling solids may be avoided altogether by the film coating, or uniformly spaced portions of plastic, on the primary rotor contacting uniformly spaced points on the secondary rotor and the stretch-orientation of the filaments accomplished by means of movement between the diverging paths of the peripheries of the two rotors; or the functions of the two rotors may be combined in one rotor by depositing the fibre-forming plastic and pulling solids in succession, one above the other.

To obtain and maintain adhesion between a heat reactive plastic and pulling solids until the filaments have reached their maximum stretch, the plastic may be heated to an adhesive condition prior or subsequent to deposition on a primary rotor; the solids may be heated sufficiently prior or subsequent to deposition on a secondary rotor to cause the plastic to acquire fibre-forrm ing fluidity and become adhesive on contact; or the plastic may be deposited in contact with the solids on one rotor and acquire fibre-forming fluidity prior or subsequent to the said contact.

The treating fluids for maintaining the filaments in, or returning the filaments to, an adhesive condition for bonding purposes may be:

elastic oxidizing fluids, such as heated air, saturated steam, etc.; non-oxidizing elastic fluids, such as superheated steam, nitrogen, CO2 gases, etc.; solvents, such as phenol and formic acid for polymeric amide filaments, acetone for filaments spun from vinyl chloride-acetate copolymers, etc.; non-solvent adhesives, such as starch, shellac, casein, latex, wax, acrylate resins, etc. Quenching or other setting fluids for the filaments may be: steam, water, oil, etc. for polymeric amides; steam, heated air, etc. for removing an acetone solvent from a celluloseacetate solution; or the setting may be accomplished simply by mechanical stretching, as in the case of the filaments spun from cellulose materials by orbweaver spiders. All such fluids for adhesion, quenching, sett ng, or other treating purposes, may be brought into contact with the filaments and pulling solids during their con veyance and deposition by the introduction of the former into, or their use as, the conveying and depositing fluids; or the deposited filaments and pulling solids may be subjected to such treating fluids by the usual spraying, dipping, or roller coating methods.

The invention is exemplified in the following descriptions, and preferred arrangements are illustrated by way of examples in the accompanying drawings, in which:

Fig. l is a vertical section of a gun and deposition drum for the making of filaments and fabrics.

Fig. 2 is a fragmentary vertical section on an enlarged scale of the upper rotor shown in Fig. 1.

Fig. 3 is a-vertical section of a modified form of the gun shown in Fig. 1.

Fig. 4 is a plan view of a fragmentary portion of the fabric produced by the spinning gun and deposition drum shown in Fig. 1.

Fig. 5 is a plan View of a fragmentary portion of a modified fabric produced bythe spinning gun and deposition drum shown in Fig. 1.

Fig. 6 is a plan view of a fragmentary portion of the fabric produced by the spinning gunshown in Fig. 3 and deposition drum shown in Fig. 1.

Fig. 7 is a plan view of a fragmentary portion of a modified fabric produced by the spinning gun shown in Fig. 3 and the deposition drum shown in Fig. 1.

Fig. 8 is a vertical section of a rotating valve for the end of the gun or ejector barrel.

Fig. 9 is a vertical section of a one-rotor spinning gun.

Fig. 10 is a fragmentary vertical section on an enlarged scale of the rotor shown in Fig. 9.

Referring to the drawings more specifically by reference characters:

In Fig. 1, pulling pellets 2 in the hopper 3 are charged with the aid of a feeding rotor 4 into the pockets or reservoirs 5 of the cylindrical liner s; and the latter encloses and turns with a top rotor l, equipped with pockets 8 and radial passages 8, the pockets inthe liner and pockets in the rotor being connected by passages It as shown more clearly in Fig. 2. In similar manher, the plastic pellets H in the hopper i2 are charged with the aid of a feeding rotor [3 into the pockets i l of the cylindrical liner I5; and the latter encloses and turns with a lower rotor it equipped with pockets l1 and radial passages 18, the pockets in the liner and pockets in the rotor being connected by passages l9. The liners for the two rotors, the two rotors, and their respective pockets are identical and all are enclosed by a casing 28. The upper rotor turns about a stationary cylindrical wall 2| which is equipped with axial upper and

lower chambers

22 and 23, respectively, having connections 24 and 25, respectively, and

ports

26 and 21, respec tively. The lower rotor turns about a stationary cylindrical wall 28 which is equipped with an axial chamber as having a connection 39 and a port 3!. A fluid treating nozzle 32 is inserted in the rotor casing.

Attached to the rotor casing is the breech of the gun barrel 33 enclosed within. a jacket 33a through which may flow a heating fluid, such as diphenyl oxide, from inlet 3% to outlet 33c; and surrounding the outer end of the barrel is an ejector 34 having an inlet 35 and an outlet A source of power, positioned externally of the rotor casing but not shown, is used to drive the upper and lower rotors in synchronized relation.

A depositing apparatus consisting of a foraminous drum 3'3 rotates about and in close contact with the stationary arms 33 of the cylindrical axis 39, and the latter encloses: the chambers as, M, and 32, having ports 43, 44, and 35, respectively, and connections 46, 47, and 48, respectively, to sources of suction; and a pressure chamber is having a port 56, and a connection 51 to a source of fluid pressure. A compression belt 52 travels over adjustable compres- 'sion rolls 53 and 5d, guiding rolls 55 and 5B, and under tension roll 51. Casing 58, seals 59, and

suction compression rolls 6!! and 6!, enclose discrete fibers or other solids as deposited from a blower upon an adjacent portion of the drum; and the solids are bonded during rotation of the drum by filaments from the spinning gun to form a fabric t2. A'fabric 63 is fed from the roll 64 and deposited upon and bonded to fabric 62 as the .latter-is-fedbetween the compresison belt and drum. Housingfii encloses a treating fluid suppliedby a nozzle 65, the fluid passing through the belt, laminated fabrics, and foraminous wall. Pulling pellets made non-adherent by quenching fluids will, upon impact with the drum, drop into the trough Bi and be carried away by the conveyor B8. The foraminous drum is driven from a source of power not shown and conveys the laminated fabrics and belt, which conveyance maybeaided by a differential pressure created by the treating fluid passing through the fabrics; or one of the rolls may be driven from a source of power not shown and the belt used to rotate the drum.

In Fig. 3, the upper rotor consists of a foraminous drum 69 which rotates about the stationary arms '78, H, 72 and 13, the drum and arms thereby forming: a neutral chamber it having no connections; suction chambers l5 and Hi, the former having a connection H to a source of suction, and'thetwo being connected by opening 58 in the arm H; having an opening 86 and a blowing chamber 19 to a source of fluid pressure. The drum is supplied with a coating of fibres 8i furnished from the carding and combing rolls 32 by an endless belt 83 which passes over a conveying roll 86. The lower rotor 85 is equipped on its peripheral surface with small pockets or reservoirs 86 for the plastic fed therein during rotation of a screw Ell, which operates within the heated housing 88; and the rotor turns about a fixed cylindrical axis 853 enclosing a heating chamber a!) supplied from a source of heat through an inlet connection 95. The gun barrel and ejector are the same as in Fig. 1 except that no heating chamber is provided for the breech of the gun barrel and a seal 92 makes connection between the upper portion of the gun barrelaand the top rotor. A doctor blade 93 is used to clip the filaments from the lower rotor.

Fig. 4 shows a fragmentary portion of a fabric of tensioned filaments s produced by the apparatusshown in Fig. 1, when the drum is rotating sufiiciently rapidly, or the relative movement between the gun and depositing surface is sufficiently great to maintain, or increase, the tension of the filaments as deposited on the drum in an intersecting condition.

Fig. 5 shows a fabricof promiscuously intersecting filaments 95 produced by the same apparatus when the drum is not rotating sufficiently rapidly, to maintain the tension of the filaments.

Fig. 6 shows the same fabric of tensioned filaments shown in Fig. 4 when short, discrete fibres 96 are used to pull the filaments, as in Fig. 3, and the fibres are bonded by the filaments.

Fig. '7 shows a fabric in Fig. 5 are used to bond Fig. 6.

Fig. 8 shows a valve suitable for connection to the end of the ejector shown in Figs. 1 and 3. It consists of a spur gear 8?, keyed to the plug 98, the former being used to rotate the latter in a casing 953 in synchronized relation with the rotors of the guns shown in Figs. 1 and 3.

Figs. 9 and 10 show a one-rotor arrangement which the filaments of the pulling fibres of from into the breech of the gun barrel.

in which the rotor, liner, and axial cylinder are the same as those used for the pulling pellets in Fig. 1, except that a vertical division plate is required to separate the two

chambers

22 and 23. An extrusion screw in close contact with the liner 6, as in Fig. 3, is utilized to charge the upper portion of the pellet filled pockets with a fibre-forming plastic 100. Both pellet and plastic feeding devices are connected to the housing I01, which encloses the rotor and is also attached to the gun barrel, 102, in which the fila ments, I03, are produced.

Example I In the manufacture of laminated layers of crepe wadding for packaging purposes, polytetrafiuoroethylene propulsion pellets of approximately .06 inch in diameter are introduced into the hopper 3 of Fig. l at room temperature and fed into uniformly spaced pockets of the foraminous liner 6 of an upper rotor of about 12 inches in diameter while the latter is travelling at a peripheral speed of about 100 feet per min ute. The pellets are held in position under a differential pressure produced by a vacuum of about 10 inches, the air passing from the liner pockets through passages iii of .04 inch in diameter, pockets 8, radial passages 9, port 2'5, into chamber 23, and through the outlet 25. Simultaneously, polyamide pellets of approximately the same diameter as the propulsion pellets and having a molecular weight of 20,000, are fed in similar manner from the hopper 12 into similarly spaced pockets of the liner of a lower rotor of the same diameter and rotating at the same peripheral speed as the top rotor. These pellets are brought to fibre-forming fluidity by contact with superheated steam of 320 F. temperature entering through connection and passing through the axial chamber 29, port 3|, radial passages I8, pockets ll, passages 19, and into the pellet pockets M, those radial passages being cut off from the steam pressure that would permit expulsion of the pellets from their pockets.

After contact between the pulling pellets and the fibre-forming pellets, the latter adhere to the former as the peripheries of their respective rotors pass through diverging arcuate paths, thereby causing each fibre-forming pellet and that portion of the latter that adheres to a pulling pellet to neck down and produce a positively stretched filament between the corresponding pellet pockets in each rotor. As each radial passage in the upper rotor becomes coincident with the port 26 a blast of heated CO2 gas at a pressure of lbs. per sq. in. from chamber 22 results in the pulling pellets in the liner pockets connected with the said port being blasted there- This superfiuid secondary stretching of the filaments between their reservoirs and their respective pulling pellets exhausts the reservoirs of their spinning material.

To aid in the secondary stretching, the pulling pellets pass out of the gun barrel and into an injector barrel where the filaments are subjected to a blast of cool air at 50 F. and velocity of 20,000 it. per min. to quench them. However, the

temperature of the quenching fluid may be anything below the softening point of the filaments, such as 212 F. for saturated steam, room temperature for air, etc. The quenching of the filaments will result in their being cold-drawn, and the polytetrafluoroethylene pellets becoming non- 8 adherent on impact with the drum and dropping into the trough 61.

The filaments may also be subjected to a third stretching by the propulsion of the pulling pellets after the former have been separated from their rotor by exhaustion of the fibre-forming reservoirs, shearing of the filaments, or other means. If the second stretching operation results in cold-drawing of the filaments, the third pulling operation will result in an additional cold-drawing; if the secondary stretching does not result in cold-drawing, the third stretching operation may or may not result in cold-drawing, depending upon such factors as the temperature and velocity of the ejector fluids, length of the gun and ejector barrels, etc.

The third stretching of the filaments may even constitute a positive pull as when the filaments are deposited in an adhesive condition, or are held by suction on the depositing drum or other surface before severance of the filaments from their rotor. In any event, the movement of the depositing surface, or relative movement between the gun and depositing surface, should be sufliciently rapid to cause the filaments to be deposited in a tensioned condition and in substantially straight lines between their bonding points, as indicated by the filaments 94 in Fig. 4. For instance, if the filaments are travelling at the rate of 2,500 ft. per min. at the time they are deposited, the peripheral speed of the depositing drum, or the relative speed between the moving filaments and their depositing surface should be greater than 2,500 ft. per min; if the movement or the drum, or the said relative movement, is not greater than the travelling speed of the filaments, the latter will be deposited in a promiscuously intersecting condition, as indicated by the filaments 95 in Fig. 5.

Flock, cellulose fibres or other solids from a disintegrating apparatus, such as that described in my U. S. Patents Nos. 2,152,901; 2,218,338; and 2,336,?45, are deposited upon that portion of the ioraminous drum Bl rotating within the orbit of the casing 00, the conveying fiuid, such as air from a blower, passing through the drum, port 43, and outlet 00. As the drum rotates in the direction indicated by the arrow, the filaments and other solids from a spinning gun are deposited upon the first web conveyed by that portion of the drum moving between the compression rolls 0i and 53, the conveying fiuid passing through the webs, drum, port 40, and outlet M.

As the drum continues to rotate, a web crepe wadding ts from roll 04 is deposited upon and bonded to the webs of intersecting filaments and discrete fibres. Or bonding of the three webs may be accomplished by passing the webs between the drum and a foraminous belt 52, where the filaments in the webs are treated to an activating or other fluid, such as steam, solvent, heated air, etc., issuing from the nozzle 65 and passing through the belt, webs, port 25, and outlet 48, the bonding being aided by the pressure exerted by the rolls and belt. The continued rotation of the drum conveys the webs beyond the suction area where their removal may be easily accomplished as a result of setting of the filaments, preliminary coating of the drum with flock, and/or air or steam blast passing through the drum from port 50 of the pressure fluid chamber 49. The laminated fabric may then be treated by spraying or other method to a water repellent, fire retardant, wetting agent, or a coating to make it impervious.

Obviously, the depositing of the three webs and the compression of any one or all of them may take place in any desired order: A web of crepe wadding may be deposited before the bonding filaments and both be followed by a second web of crepe wedding; or a great many webs of crepe wadding may be deposited and between each a web of bonding filaments to form a laminated structure of many layers such as would be required for insulation or packaging purposes. In like manner, can bonding filaments, with or without layers of crepe wadding, be spun completely around articles to be enclosed by the rapid rotation of the latter, or by a rapid relative movement between the depositing fabrics and the article to be enclosed.

Example II In the manufacture of enclosures for beef carcasses, sanitary napkins, etc., cellulose or other discrete fibres 8! are parallelized, rolled, and thinned out by the conventional carding, combing and drawing equipment 82, and deposited as a web on the surface of a foraminous rotor 69, a indicated in Fig. 3; or the discrete fibres may be deposited on the rotor by a method similar to that just described for the depositing drum. In any event, the discrete fibres are held on that section of the periphery of the rotor between

arms

10 and 72 by suction from outlet 71. A polyamide plastic is deposited in fibre-forming fluidity at a temperature of about 400 F. by extrusion screw 87 in the pockets or reservoirs of the lower rotor 85, both rotors being about 24 inches in diameter and travelling at about the same peripheral speed as in Example I. The fibres and discrete and uniformly spaced portions of fibreforming material contact one another and the latter is attenuated into filaments, as described in Example I.

As the periphery of the upper rotor reaches the position between

arms

72 and 13, the discrete fibres are subjected to a blast of elastic fluid, such as air, at room temperature and pressure of 50 pounds per square inch from the inlet 80. This may be slightly in advance of exhaustion of the plastic pockets, or the shearing of the filaments by polytetrafluoroethylene coated knife 93 from the plastic pockets on the lower rotor, which the filaments connect to the discrete fibres on the portion of the upper rotor about to be subjected to the blast of elastic fluid.

The other operations for stretching and depositing the filaments are the same as described in Example I, except that the discrete pulling bres are deposited in a promiscuously intersecting condition and bonded by stretch-oriented filaments. If the movement of the depositing surface, or relative movement of gun and depositing surface, is sufficiently rapid, the filaments will be deposited in a tensioned condition, as indicated by the filaments 94 in Fig. 6; if the said movement is not sufiiciently rapid both will be deposited in a promiscuously intersecting condition, as indicated by the filaments 95 and fibres 96 in Fig. 7.

Meat, vegetables, fruit, etc. may be packaged thus in non-woven enclosures of intersecting filaments spun about the foodstuff, the interstices of the intersecting filaments then sealed by a spray, brush, or dip coating of gelatin, wax, or other suitable material; and simultaneously with the sealing all air-pockets may be removed from the package by the cold-drawing of the filaments under a diiferential air pressure by means of a ,gun or ejector barrel to maintain connection to a vacuum pump. The foodstuff may be packaged while fresh and unfrozen, or it may be packaged subsequent to freezing; or the freezing may be accomplished simultaneously with or subsequent to the packaging. A strong, flexible, moisture-vapor-proof, and air-tight package can be spun about a beef carcass, and in close adherence to all sides of the carcass, at the time and place required, which will effectively prevent loss of moisture,-freezer burn, disoolorization and impairment of bloom. In similar manner, can enclosures be built about other kinds of articles, such as potted plants, which which require neither freezing nor exhaustion of air for their preservation. And when additional safeguards are required to avoid breakage or injury, the article may be first enwrapped with crepe wadding or other soft resilient fibrous material and then backed by a non-woven fabric of great strength, such as that described above.

Example III In the manufacture of a flexible, fireproof in,- sulating fabric, pellets or other discrete solids, containing free moisture or water of constitution, such as vermiculite minerals, are substituted for the polytetrafiuoroethylene pellets of Example I. The pulling pellets are introduced into the pockets of the upper rotor in Fig. 1 and subjected to saturated steam pressure of lbs. per sq. in. and a temperature of 350 F. from steam entering the inlet 25. The pulling solids are propelled within the gun barrel by steam at lbs. per sq. in. entering the pockets from inlet 24, a vertical division plate being used to divide the two

pressure chambers

22 and 23, as in Fig. 9. The length of the gun and/or ejector barrels may be regulated and muzzle areas restricted so that explosion of the pulling solids cannot take place until after emission of the solids from the barrel. Or a rotating valve, such as described in Fig. 8, may be attached to the muzzle of either the the necessary pressure in either or both barrels before explosion takes place. In such a case, the rotation of rotor and valve may be synchronized so that propulsion of the pellets will occur slightly in advance of the opening of the valve. The exploding of the solids will separate the latter from the filaments, and both may then be deposited to form a fabric in which the expanded or exploded solids are bonded by stretch-oriented, tensicned or non-tensioned, filaments, as described in the above examples.

Obviously, vermiculite solids may be expanded in a prior operation, the expanded or exploded solids distributed uniformly over the foraminous periphery of the top rotor in Fig. 3 in a second operation, and the filaments stretched and deposited, as already described, to form the same kind of fabric.

Example IV In the manufacture of filter fabrics, frangible, diatomaceous earth, pulling pellets, loosely bonded by pressure and free moisture, and polyethylene fibre-forming pellets of 20,000 molecular weight are substituted for the pulling and spinning pellets, respectively, in Example I, and the former exploded as in Example III. The resulting dust with filaments are deposited on the drum by the conveying fluid passing through the drum, and the dust is bonded by the filaments. In this case, the fibre-forming polymer may have an initial velocity of 200 ft. per min. for its primary stretching, and this may be speeded up to 2,000 ft. per min. during deposition by a blast of superheated steam at a temperature of 400 F. from the ejector, which temperature in the ejector will be sufficient to maintain the filaments in an adhesive condition at a much lower temperature during deposition. After the secondary stretching the plastic reservoirs are subjected to a blast of cool air at a temperature of 50 F. from nozzle 32 to render the residue non-adherent to the pockets in a polytetrafiuoroethylene liner.

By using a pulling pellet rotor, as shown in Fig. 1, feeding the polyethylene into plastic reservoirs, as shown in Fig. 3, and speeding up the rotors to give a peripheral speed of 10,000 ft. per min, it is possible to throw the diatomaceous earth pellets out of their reservoirs by centrifugal action and thereby stretch the filaments without the aid of suction or pressure from the axial chambers of either rotor. The centrifugal action results in the pellets striking the sides of the breech of the gun barrel and disintegrating into powder, and the latter with the stretched filaments being conveyed by air entering the breech, where the seal 92 in Fig. 3 is omitted, induced by the fluid stream pressure from the ejector. The air stream redirects the movement of the filaments on disintegration of the pellets, and coating the breech of the gun barrel with polytetrafluoroethylene prevents sticking of the filaments to the breech during the said redirection.

Example V In the spinning of protective fabrics over freshl'y seeded ground to prevent injury from frost, escape of moisture, baking of the earth, etc, a copolymer of vinyl chloride and vinyl acetate may be brought to fibre-forming fluidity when used in the proportion of 13 per cent vinyl chloride, 2 per cent vinyl acetate and 85 per cent acetone. The solution is charged into the reservoirs of a primary rotor by means of an extrusion screw, as in Fig. 3, to contact fertilizer pulling pellets fed into the pockets of a secondary rotor, as in Fig. 1, both travelling at a peripheral speed of 100 ft. per min. The pellets are propelled by an air blast from inlet 24 and both filaments and pellets are conveyed in an air stream through two ejectors, the first as already described, and the second positioned on the barrel of the first. The first ejector is used to coat the filaments with aluminum powder while the filaments are still in an adhesive condition, and the second coats the aluminum covered filaments with an animal glue so that the filaments adhere to one another as deposited over the ground. Weathering conditions will disintegrate the fertilizer pellets almost immediately and ultimately cause the disintegration of the fabric when the need for such a protective covering is past.

In this example, the acetone is dissipated in the air and cannot be recovered. It is therefore usually advisable to use a suitable fibre-forming plastic that can be brought to a fibre-forming fluidity by heat, stretched into filaments, and the latter bonded to one another, all without the use of a solvent.

Example VI In the spinning of certain fabrics for clothing, insulating purposes, etc, cellulose acetate may be extruded at a temperature of 400 F. as a film coating over a primary rotor to contact uniforznly spaced points or areas on, or the spaces between the pockets of, a secondary rotor. After primary stretching, the filaments are clipped at either end by doctor blades or the sharp edges of the breech of the gun barrel; and subsequently to their severance, they are conveyed through an ejector in an adhesive condition and coated by aluminum powder. The aluminum covered filaments are then deposited on the drum and held in position by suction until bonded together by adhesive tape or a fabric from roll 64; or they may be bonded into an integral fabric by an adhesive spray from nozzle 66, or an adhesive roller coating from the belt 52. Or the filaments without an aluminum coating may be deposited on the drum in an adhesive condition and bonded to aluminum foil from roll 64 as both are fed between the compression rolls and drum.

Obviously, a film coating on a primary rotor may contact either uniformly spaced, or uniformly distributed, pulling solids on a secondary rotor, and subsequent operations accomplished as already described. However, in the latter case, the spacing of the filaments will not be uniform. Or a suitable plastic may be charged into the pockets of a primary rotor in fibre-forming fluidity, or in solid form, and brought by heat to fibre-forming fluidity, and contacted with uniformly spaced points on a secondary rotor and attenuated into filaments without the aid of pulling solids, as described into the above example.

Example VII In the manufacture of abrasive sheets for sanding belts, safety walks, etc, corundum pellets are used for stretching vinylidene chloride filaments and both are used under substantially the same conditions as those described in Example I, except that the corundum pellets are incorporated in the fabrics as a plurality of layers are built upon an endless carrier. Or the abrasive pellets may be preheated, or heated in hopper 3 to a suitable temperature, to contact unheated plastic pellets at a temperature of 400 F., and the stretching and deposition on the drum accomplished, as already described. The abrasive solids after being bonded by stretch-oriented filaments can then receive a paper or cloth backing from roll 64.

Example VIII In the spinning of fabrics for various purposes, a single rotor may be substituted for the two rotors in Example I, and molten polyamide fibreforming polymer deposited by an extrusion screw as a film coating I00 over the polytetrafiuoroethylene pellets and pockets, as shown in Figures 9 and 10. The film coating may not completely cover the pockets but it will restrict the size of the opening through which the pellet will be propelled, and the propulsion of a pellet will result in the plastic at the sides of the pocket being drawn into two or more filaments. Obviously, the shape of the pocket may be made to regulate the number and shape of filaments produced.

It is also evident that: smaller fibre-forming solid pellets may be fed into a pocket above and at the side of a larger pulling pellet and the former brought to a fibre-forming fluidity by steam at a suitable temperature from connections 24 and 25, as already described; a fibreforming pellet or pellets may be fed into a pocket and held there by suction or by bringing the pellet or pellets to an adh sive fluidity by a suitable heated fiuid from connection 25, and the pulling pellet deposited in the pocket above and in contact with the fibre-forming pellet or pel-' lets; or a fibre-forming film coating and uniformly distributed pulling solids may be deposited on the rotor in superposed relation, and the propulsion and stretching operations accomplished as already described.

.While specific sizes, velocities, temperatures, etc., have been given in the examples cited, it is obvious that they may vary within wide limits. For instance, the molecular weight of the fibreforming plastics may vary between 10,000 and 50,000; the sizes of the rotors may be 6 in. dia. for laboratory work, or they may be 6 ft. for plant scale production; the peripheral speed of the rotors may be 1 ft. per min., or it may be 10,000 ft. per min.; the weight of the pulling pellets may be grain, troy weight, for perlite pellets used in insulation fabrics or 3 grains, troy weight, for polytetrafiuoroethylene pellets required in the manufacture of packaging materials; the fibreforming fluidity temperature of the plastic may be 500 F. for a polymeric amide or atmospheric temperature for a vinylchloride resin; the velocity of the propulsion fluid may be anything that will propel the pulling pellet, or it may be 50,000 ft. per min. for an inert nitrogen gas required for stretching a polyamide filament; and these values may vary much more than indicated by the above figures.

. It will be obvious from the foregoing descriptions that stretching of the filaments may be accomplished by a great variety of methods: a positive stretching between the rotors; a superfluid stretching between fiuid-conveyed pellets and the pockets for the fibre-forming plastic in one of the rotors; a super-fluid stretching by propulsion of the pellets pulling trailing filaments; a positive pull between a depositing surface and the said pockets of one of the rotors; and propulsion by centrifugal action may be substituted for the stretching by other means.

It will also be evident that cold-drawing of the filaments may be accomplished in any one or all of the said stretching operations by varying the conditions of the treating fiuids indicated; and if the filaments are deposited in a set condition, they must be made adhesive during or prior to deposition or else be held in position by suction within a depositing drum, or vacuum produced within the article being packaged or otherwise enclosed, until activated or made adhesive, as. already described.

It will be understood throughout the specification and appended claims that: a tensioned filament is a filament that is held taut between two points; an integral fabric of tensioned filaments is a fabric in which each filament is held taut between the points of intersection at the time of bonding; and superfiuid pulling or stretching force means a force in excess of that which can be produced by a fiuid stream alone.

I claim as my invention: 1

1. In a method for attenuating fibre-forming material into filaments by propulsion of discrete solids adherent therewith, the steps comprising: depositing the said solids upon a retaining wall; moving the said wall through an endless circuit to bring the said solids into adhering contact with the said material; and propelling the said solids with a portion of the said adherent material from the said wall during the said movement to attenuate the said material into a continuous succession of discontinuous filaments of substantial length and strength,

2. In the method of claim 1, the said steps in which the said propulsion force is exerted against all 14 the said solids in a direction transverse to the movement of the said wall.

3. In the method of claim 1, the said steps in which the said propulsion force is a fluid stream. 4. In the method of claim 1, the said steps in which the said propulsion force is an elastic fluid.

.5. In the method of claim 1, the said steps in which the said propulsion is by force of centrifugal action.

6. In the method of claim 1, the said steps in which the said propulsion force is a quenching fiuid to set and cold-draw the said filaments.

7. In the method of claim 1, the said steps in which the said filaments are set and attenuated to the initial point of their elasticity during the said propulsion of the solids.

8. In the method of claim 1, the said steps in which the said contact is made with finely divided portions of the said material.

9. In the method of claim 1, the said steps in which the said wall is foraminous, and the said propulsion is exerted by passage of a fluid stream through the said wall.

10. In the method of claim 1, the said steps in which the said wall is foraminous, and the said solids are maintained in position on the said wall by suction exerted within the wall, and are propelled from the wall by fiuid pressure passing through the wall.

11. In the method of claim 1, the said steps in which the said material is organic and the said solids are inorganic.

12. In the method of claim 1, the said steps in which the said material and said solids are deposited on the said wall in superposed relation.

13. In the method of claim 1, the said steps in which the said filaments are produced attached to the said solids, and including the additional step of separating the said solids from the said filaments.

14. In the method of claim 1, the said steps in which the said movement is a continuous rotation of the said wall during which the said operations are constantly repeated to produce filaments of from 5 to 20 feet in length.

15. In the method of claim 1, the said steps in which successive portions of the said material contact successive portions of the said solids, and the said solids are propelled at comparatively great speed by a succession of impulses to produce a constant flow of filaments.

16. The method of producing discontinuous filancients of substantial length and strength from a fibre-forming material comprising: depositing the said material upon a primary wall; depositing discrete solids upon a secondary wall; moving the said walls through endless circuits that converge and diverge whereby the said material and said solids are brought into adhering contact during the converging movement and the said material is attenuated into discontinuous filaments during the diverging movement; and propelling the said solids from the said secondary wall during the said diverging movement, by force of a fluid stream to increase the attenuation of the said filaments.

17. The method of claim 16 in which the said material is deposited in finely divided portions.

18. The method of claim 16 in which the said solids are deposited in uniformly spaced portions.

19. The method of claim 16 in which the said material is deposited in finely divided portions, and the said solids are deposited in spaced relation to register with the said portions, during the said movements of the walls.

20. The method of claim 16 in which the said attenuation of the said material into filaments is accomplished at comparatively slow speed, and the said increase in attenuation of the filaments is accomplished at comparatively great speed.

21. The method of claim 16- in which the said solids are separated from the said filaments by disintegration of the solids.

22. The method of claim 16 in which the said solids are separated from the said filaments by explosion of the solids after the said increase in attenuation of the filaments.

23. The method of claim 16 in which the said solids are separated from the said filaments, after deposition of the filaments, by passing a solvent for the solids through the deposited filaments.

24. The method of claim 16 including the steps comprising: severing the said filaments from the said primary wall; and propelling the said solids after the said severance to give additional stretch to the said filaments.

25. The method of claim 16 in which the said material is deposited in discrete solid portions, and the said solid portions reduced to fibre-form ing fluidity by heat during the said movement of the primary wall.

26. The method of claim 16 in which the said material is deposited in discrete solid fusible portions, the said portions reduced by heat to fibreforming fluidity during the said movement of the primary wall, and the said fiuid portions while still unset and nonelastic attenuated into filaments.

27. The method of claim 16 in which the said material acquires fibre-forming fluidity at temperatures between atmospheric and 500 F., and the said solids remain noniusible at the said temperatures, during the said movements of the walls.

28. The method of making a nonwoven fabric comprising the method of claim 16 for producing filaments which are attached in predetermined relation to the said solids, and including the step of depositing the said filaments and said solids in the said predetermined relation to form a web.

29. The method of claim 28, including the steps of passing a wash fluid through the said web to remove the said solids, and bonding the said filaments to one another.

30. The method of claim 28, including the step of bonding the said solids by the said filaments.

31. The method of claim 30 in which the said bonding is accomplished by depositing the said laments in an adhesive condition.

32. In an apparatus for producing fibres, the combination of: primary and secondary rotors having peripheral walls that converge and diverge with each other in their movements through endless circuits; means for supplying a fibre-forming material to at least one of the said walls, the walls being so constructed and arranged that they are adherently connected by the material during their said converging movement, and the material is attenuated into fibres during their said diverging movement; and means for discon-' meeting the ends of the said fibres from one of the said walls and increasing the stretch of the fibres before their severance from the other of the said walls.

33. In an apparatus for producing fibres, the combination of: primary and secondary rotors whose peripheral surfaces converge and diverge with each other during their rotative movements; a primary feeding means for supplying fibreforming material to the said peripheral surface of the primary rotor; a secondary feeding means for suppiying discrete solids to the said peripheral surface of the secondary rotor, the said rotors being so constructed and arranged that the said solids and the said material are adhesively contacted during the said converging movement, and the said material is attenuated into discontinuous fibres of comparatively short length during the said diverging movement; and means for supplying a propulsion fluid to blast the said solids from the secondary rotor during the said rotative movements whereby the said discontinuous fibres oi comparatively short length are removed from connection with the secondary rotor and stretched into discontinuous fibres of substantial length by pull of the solids conveyed by the said propulsion fiuid.

3 In an apparatus for producing nonwoven fabrics, the said combination of claim 33 in which the said fibres of substantial length are attached in predetermined relation to the said solids, and including: a foraminous retaining structure adapted to move through an endless path; means Within the said structure for drawing the said propulsion fiuid therethrough to deposit the said solids and fibres thereupon during a continuous movement of the structure through the said path; and means for bonding the said deposited fibres and solids in the said predetermined rela tion into an integral fabric.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 692,631 Cooley Feb. 4, 1902 1,137,814 Von Pazsiczky May 4, 1915 2,159,945 Slayter Mar. 21, 1939 2,156,455 Kleineet al. May 2, 1939 2,181,043 Boeddinghaus Nov. 21, 1939 2,278,895 Rugeley et al. Apr. '1, 1942 2,326,174 Rutishauser Aug. 10, 1943 2,357,392 Francis Sept. 5, 1944 2,369,506 Weibel Feb. 13, 1945 2,37%,549 Hall Apr. 24, 1945 2,385,358 Hanson Sept. 25, 1945 2,411,660 Manning Nov. 26, 1946 2,437,264 Manning Mar. 9, 1948 2,509,735 Horsak May 30, 1950 2,522,526 Manning Sept. 19, 1950 OTHER REFERENCES Gersch, pp. 152 to 158 and 189 of April 1947 issue of Natural History.

Claims

1. IN A METHOD FOR ATTENUATING FIBRE-FORMING MATERIAL INTO FILAMENTS BY PROPULSION OF DISCRETE SOLIDS ADHERENT THEREWITH, THE STEPS COMPRISING: DEPOSITING THE SAID SOLIDS UPON A RETAINING WALL; MOVING THE SAID WALL THROUGH AN ENDLESS CIRCUIT TO BRING THE SAID SOLIDS INTO ADHERING CONTACT WITH THE SAID MATERIAL; AND PROPELLING THE SAID SOLIDS WITH A PORTION OF THE SAID ADHERENT MATERIAL FROM THE SAID WALL DURING THE SAID MOVEMENT TO ATTENUATE THE SAID MATERIAL INTO A CONTINUOUS SUCCESSION OF DISCONTINUOUS FILAMENTS OF SUBSTANTIAL LENGTH AND STRENGTH.