US2750317A - Method and apparatus for making non-woven fabric - Google Patents

Description

June 12, 1956 F. w. MANNING METHOD AND APPARATUS FOR MAKING NON-WOVEN FABRIC Filed Oct. 8, 1953 2 Sheets-Sheet l IN V EN TOR.

June 12, 1956 F. w. MANNING 2,

METHOD AND APPARATUS FOR MAKING NON-WOVEN FABRIC Filed Oct. 8, 1953 2 Sheets-Sheet 2 INVENTOR atent Ofllce Patented June 12, 1956 METHOD AND APPARATUS FOR MAKING NON-WOVEN FABRIC Fred W. Manning, Palo Alto, Calif.

Application October 8, 1953, Serial No. 384,882

13 Claims. (Cl. 154-101) My invention relates particularly to improved methods and apparatus for producing fire-resistant filaments and fabrics for insulation purposes, also fabrics for battery separators, filters, and the like. This application is a continuation-in-part of my copending application, Serial No. 185,240, filed September 16, 1950, subsequently issued as Patent No. 2,687,363.

In the said copending application, I disclosed how filaments and fabrics can be produced from regulated sources of supply of organic, fibre-forming materials by uniting portions of the material to discrete solids, positively withdrawing the solids to attenuate the adhering portions into filaments, propelling the solids by force of fluid streams to increase the attenuation of the filaments, and then depositing the latter to form fabrics of greater strength than is possible by prior methods. In the present application, I disclose how inorganic filaments and fabrics can be produced by similar methods. (The words glass and perlite throughout this application are used in a generic sense, the former to include glass and mineral fibre-forming compositions and mixtures thereof, and the latter to include all siliceous materials of volcanic origin that expand under heat.)

Prior practice has been to manufacture discontinuous glass filaments by a blast of an elastic fluid, such as steam or air, directed against streams of the molten material. This action produced filaments of uncertain length, usually ranging from two or three inches to fifteen inches, and commonly called staple fibres. Moreover, blasts of elastic fluids directed against solid, smooth surface streams of molten material cannot ordinarily produce filaments of great strength, or filaments whose diameter strength are uniform.

I am also aware that it has been common practice to make nonwoven fabrics from several different staple fibres varying in size and strength by intermixing them, and sometimes the intermixed fibres were bonded together, as for example, a fabricated body of glass fibers intermixed and bonded with asbestos fibres. But to intermix means to mingle together, and my combinations are never produced by mingling. Primary fibres are attached to predetermined portions of secondary fibres or other solids for the purpose of aiding in stretching the former which with the pulling solids are deposited and bonded into a fabric in that predetermined relation.

It is a primary object of my invention to provide a method and means whereby inorganic, fibre-forming materials may be deposited in discrete portions of predetermined size on a primary member, the portions positively attenuated into comparatively short discontinuous filaments by cooperation between the primary member and a secondary member, and the filaments then propelled by the pull of secondary discrete fibres or other solids conveyed by a fluid stream whereby the short discontinuous filaments are stretched into discontinuous filaments of comparatively great length, as for instance, filaments from 2 to feet in length produced from glass portions from .02 to .06 inch in diameter.

Another object of my invention is to bond discrete, inorganic, fire-resistant materials, such as asbestos, perlite, metal flakes, micaceous materials, and short glass fibres of little strength, by discontinuous glass filaments of comparatively great length and strength.

An additional object is to produce discontinuous filaments of more uniform length, diameter, and strength than have been obtainable by prior methods.

A further object is to deposit filaments substantially lengthwise of the fabric, and in approximately uniformly overlapping lengths which intersect one another to produce a fabric of great strength. I

Another object is to furnish a fabric in which the porosity is easily regulated, such as would be required for acid filters and battery separators. Other objects will become apparent from the following descriptions.

In accordance with certain aspects of my invention, glass is deposited in discrete fibre-forming fluid and adhesive portions on the peripheral surface of a primary member moving through an endless circuit. Simultaneously discrete solids of fibre-resistant material to be bonded by the filaments are deposited on an adjacent peripheral surface of a secondary member, also moving through an endless circuit. The converging and diverging paths of the two surfaces result in contact being made between the glass portions and the fire-resistant solids, and the glass portions being attenuated into filaments of a given length. The fire-resistant solids are then propelled by force of a fluid stream to increase the attenuation of the filaments. Sometimes, however, it is desirable to deposit the glass on a primary member in discrete solid portions, and reduce the solid portions to fibre-forming fluid and adhesive portions before contact with fireresistant solids, or by contact with heated fire-resistant solids.

The filaments thus produced can be deposited in an adhesive condition on a collecting member, such as a drum or belt moving through an endless circuit, and will form a flexible web in which the fire-resistant material is bonded by the filaments. The filaments can then be set and the fabric consolidated by suitable rolls. However, if the filaments are stretched and deposited at a temperature below that at which they are adhesive, they can be bonded by a vinyl, polyester, phenol-formaldehyde, or other resin, and then subjected to calendering and quenching to cure a thermoplastic resin, or calendering and heating to set a thermosetting resin.

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

Fig. 1 is a vertical section of a spinning gun, also of a deposition drum, for the production of filaments and fabrics.

Fig. 2 is a plan view of the deposition drum shown in Fig. 1.

Fig. 3 is a vertical section of a modified arrangement of the spinning gun shown in Fig. 1.

Fig. 4 is a fragmentary vertical section, taken on line 4 of Fig. 5, showing a modified arrangement for feeding a fibre-forming material to the top rotor of the spinning gun shown in Fig. 1.

Fig. 5 is a fragmentary View, part cross-section and part elevation, taken on line 55 of Fig. 4.

Referring to the drawings more specifically by reference characters:

Fig. 1 shows an arrangement in which a fibre-forming material 1 is brought to a suitable temperature in a furnace 2 for spinning, and then passed through the depending boot 3 under a low pressure to fill the small pockets or reservoirs 4 in the primary rotor 5 with which the boot is in close contact, each reservoir containing a willcient amount to produce a filament of the required length and diameter. Pulling pellets 6 in the hopper 7 are charged with the aid of a feeding rotor 3 into the pockets or reservoirs 9 of the cylindrical liner it). The latter encloses and turns with a secondary rotor 11 which is equipped with pockets 12 and radial passages 13, the pockets of both liner and rotor being connected by passages 14. This secondary or lower rotor turns about a cylindrical wall 15, which is held in a fixed position between the sidewalls of the rotor housing, as shown in Fig. 5. This fixed wall is equipped with upper and lower axial chambers 16 and 17, respectively, having connections 18 and 19, respectively, and ports 2d and 21, respectively.

Both rotors are enclosed in a housing consisting of a refractory material 22 which is enclosed within a steel sheel 23. A spinning barrel 24, also of refractory material and enclosed in a steel shell 25, is attached to one side of the housing, and through this barrel the pellets are propelled. Burners 26 and 27 are mounted in apertures in the top left and right hand corners of the housing, and serve to maintain the fibre-forming material at a suitable temperature during the spinning operations. The rotors are rotated in synchronized relation by means of side rim gears, shown in Figs. 4 and 5, so that the discrete portions of fibre-forming materials in the supply pockets of the top rotor and the pellets in the corresponding pockets in the lower rotor register and contact when the converging paths of the peripheries of the rotors meet. As the paths diverge filaments of comparatively short length 28 are formed which are attenuated into filaments of comparatively great length 29 when the pellets are blasted from the lower rotor. Finally the pull on the filaments either exhausts the reservoirs of fibre-forming materials or the filaments are severed by a flame from the jet 31.

The filaments after being stretched and separated from their rotor are deposited substantially tangentially on a closed foraminous drum 32, the ends of which are equipped with hub 35. The drum is rotated by rollers 33, and the latter driven from a source of power not shown. The arms 34, about which the drum rotates, have no rotative motion but move back and forth on a stationary shaft 36, guided by short feather key 37, under pressure on the hubs of the drum from eccentrics 38 and 39. These eccentrics are keyed on shafts 40 and 41, respectively, are also driven from a source of power not shown, and act in synchronized relation so that when one eccentric is forcing the hub in one direction the other eccentric is retracting in the opposite direction. This back and forth movement of the drum, the extent of which is indicated by dotted lines 42 and 43, results in the filaments intersecting in wavy lines during deposition, but they still maintain their parallel lines running lengthwise of the fabric.

Air is constantly exhausted from the enclosure, adjacent to that portion of the drum on which the filaments are being deposited, through a suction outlet 44, and the latter is connected exteriorly of the drum through an axial turning joint to a source of suction, neither of which are shown. A spray from nozzle 45 is used for bonding, quenching, and other treating purposes, and the effectiveness of any treating fluid on the fllaments and other solids being deposited is increased by the exhaustion of the fluid through the suction outlet. A pipe connection 46 to the annular calender roll 47, supported by arms 48, is used for circulating cooling water when curing a thermoplastic resin, or for steam when setting a thermosetting resin. Such thermoplastic or thermosetting resins are used for bonding glass filaments together or glass filaments to a film or other web for reinforcing purposes. When paper, aluminum foil, vinylidene chloride, vinylchloride-acetate, or other film is to be reinforced by glass filaments, such a film can be fed from the roll 49 into contact with the glass filaments, and the two bonded together by an adhesive, quenching or heating, and calendering, as already indicated.

Fig. 3 shows an arrangement in which discrete fibres 50 are conveyed by an endless belt 51 over a roll 52 and deposited in a uniformly distributed condition on the periphery of a. foraminous drum or rotor 53. This drum, which is in rolling contact with the lower rotor, rotates about the stationary arms 54, 55, 56 and 57, held in fixed position between the sidewalls of the housing, thereby forming: a neutral chamber 58 having no connections; suction chambers 59 and 60, the former having a connection 61 to a source of suction, and the two being connected by an opening 62 in the arm 55; and a blowing chamber 63 having a connection 64 to a source of fluid pressure.

The lower rotor 65 is equipped on its peripheral surface with uniformly spaced pockets or reservoirs 66 for the filament forming material 67. This latter is first introduced into hopper 68 in discrete and finely divided portions, as from 50 to 200 mesh. The rate of feed of this material is regulated by a rotary valve 69 at the entrance to the feed pipe '70, and the material is then delivered in fibre-forming fluidity against the periphery of the rotor by a blast from the burner 71, which is supplied by fuel and air under pressure through pipe 72 from a source of supply not shown. A scraper 73, pressured by a spring 74, removes excess from the surface of the rotor and the drip escapes through the drain 75 in the refractory wall 76 and steel casing 77.

The sidewall extends into a stretching barrel similar to that described in Fig. 1. As in Fig. 1, when the peripheries of the rotors 53 and 65 enter diverging paths, short discontinuous filaments 78 are formed which are attentuated into long discontinuous filaments 79 when the fibres connected at its outer end are blasted from that portion of the forarninous drum passing over the pressure chamber 63. A jet flame 80 may be used to sever the inner ends of the filaments, if the pull on the lattr does not completely empty the pockets of their fibreforming material.

Fig. 4 shows another modification of Fig. l in which the molten fibre-forming material from the furnace is extruded from a spinneret or other extrusion device 81 and distributed in threads or a film coating 82 about the rotor 83. These threads or film coating may be contacted at uniformly spaced intervals by pulling solids 6 in the pockets 9 of the lower rotor, as shown in Fig. 1.

Fig. 5 shows a driving arrangement that may be used for the rotors in Figs. 1, 3 and 4. The fibre rotor (the one that receives the fibre-forming material) is mounted on a shaft 84, which turns in bearings 85 supported by the housing, and is driven from a source of power not shown. The pellet rotor (the one that receives the pulling solids) is rotated from the fibre rotor by means of rim gears 86 attached to both sides of both rotors, but rolling contact may be used to rotate the pellet rotor when the pulling solids are distributed over the periphery of the latter, as in Fig. 3.

The following examples of operational details illustrate how glass filaments can be used with various types of heat resistant solids in the manufacture of reinforcing of my fabrics, but they do not limit the invention.

Example I In the manufacture of flexible, lightweight, fireproof, insulating fabric for prefabricated houses, aircraft equipment including landing mats, etc., expanded micaceous minerals bonded by glass filaments are used, as indicated in Figs. 1 and 2.

Molten glass 1 flows from a melting chamber 2 through a feeding device 3 into uniformly spaced pockets 4 of about .06 inch in diameter positioned in a plurality of rows on the peripheral surface of a rotor 2 to 4 feet in diameter and 12 inches in width. The rotor travels at a peripheral speed of 300 to 400 feet per minute and is enclosed within a heat refractory housing 22 where a fibre-forming temperature of between l900 to 2100 F. is maintained by means of burners 26 and 27.

Expanded micaceous mineral, such as vermiculite pellets 6, preferably weighing between 5 and pounds per cubic foot and which will pass through number 4 mesh, are fed from a supply hopper 6 by means of a regulating valve 8 into uniformly spaced pockets 9 of about .25 inch in diameter in the periphery of a liner 1%} enclosing and traveling with a secondary rotor Ill. This liner and rotor, when taken together, will hereinafter be called the secondary rotor. It has the same outside diameter and travels at the same speed as the primary rotor, and both liner and rotor, like the primary rotor, are made of some heat resisting material, such as a Nichrome alloy. The rotors move first through con verging paths until the contents of their registering pockets contact and adhere, and then through diverging paths during which the glass portions neck down and are attenuated into filaments 28. During these converging and diverging movements the vermiculite pellets are maintained in the pockets of their liner by suction from outlet 18 exerted through top axial chamber 16 and port 29 of the stationary axis 15, radial passages 13 and pockets 12 of the rotor, and radial passages 14 to the pockets 9 of the liner 10.

When a radial passage 13 registers with the port 21, the liner pockets connected therewith are subjected to heated air or steam pressure blast passing from the pressure fluid connection 19 through the port from the lower axial chamber 17. This blast gives a theoretical initial velocity of at least 10,000 feet per minute to the vermiculite pellets 3:), the pull of which produces filaments 29 of substantial length, as from 2 to feet; and the temperature of the blast, length of the stretching barrel, and the restriction of the barrels outlet, are sufficient to maintain a tempertaure that will prevent setting of the glass filaments until they have reached the maximum length commensurate with the velocity of the blast, and size and weight of the pellets.

Immediately upon completion of this secondary stretching, the filaments are severed from their source of supply by a flame from jet 31. Continued movement of the top rotor results in the pockets being replenished from the depending boot 3 which is maintained in close contact with the surface of the rotor.

These filaments of substantial length, whose inner ends have been severed from their rotor and whose outer ends are attached to their pulling pellets, are now conveyed by the fluid blast from the lower rotor until they are deposited on the surface of a foraminous drum 32 where the vermiculite pellets are bonded by the glass filaments into an integral fabric by means of an adhesive, heat and pressure, such as a polyester resin from nozzle 45, and heat and pressure from the roll 47; and to aid in this fabrication the conveying fluids are drawn through the surface of the drum during deposition of the filaments and vermiculite.

The filaments are deposited tangentially to the rotating surface of the drum whose peripheral speed is greater than the final velocity of the outer ends of the filaments before deposition, which peripheral speed in the present case is between 7500 and 10,000 feet per minute. Accordin ly, the filaments are deposited substantially lengthwise of the fabric, and to make them intersect one another the drum is given a lateral reciprocating movement by means of eccentrics 38 and 39. Obviously, to produce a fabric of promiscuously intersecting filaments in which the latter are deposited at random, it is only necessary to deposit the filaments more directly upon the drum, reduce its peripheral speed below that of the outer ends of the filaments just prior to their deposition.

"scribed, when the glass is fed upon the periphery of the 6 upper rotor in the form of threads or film coating 82, as shown in Fig. 4, to contact uniformly spaced pulling solids of Example I.

The size of the threads or thickness of the film coating is regulated by the size of the orifice or openings in the outlet 81. For most purposes, the diameter of the threads, or depth of film coating, need not exceed .01 inch to be completely removed by the vermiculite or other pulling solids fed onto a secondary rotor by such means as shown in either Fig. 1 or Fig. 3; or threads or film coating may be drawn upward through an opening in the rotor casing from a melting furnace positioned immediately below the lower rotor of Fig. 3, and the excess removed by a scraper '73 positioned at a suitable distance from the rotor to maintain the required depth of thread or film coating.

Example III in the manufacture of another type of insulating fabric, expanded perlite in powder or pelleted form and weighing preferably between 5 and 15 pounds per cubic foot and a glass having a fibre-forming temperature between l606 and 1900 F., are substituted for the vermiculite and glass in Examples I and II.

In this and prior examples, the fibre-forming temperatures maintained by the burners 26 and 27 are sufliciently high to bring about a rapid expansion of the free moisture and water of constitution contained in unexpanded vermiculite or perlite solids, and the speed of their propulsion is sufiiciently great to accomplish this without danger of their coalescence or fusion to the walls of the spinning chamber. Therefore, when desirable, either can be fed onto the surface of the rotor and expanded during conveyance on the latter and/or by fluid blast through the spinning chamber. If complete expansion, or expansion in part, is to take place during conveyance by the rotor, the pellet pockets must be of suflicient size to take care of any such expansion. However, for many purposes it will be found more convenient to feed the pulling solids, expanded, unexpanded, or nonexpan sible, onto a secondary rotor consisting of a foraminous drum of fine mesh, as for instance 100 mesh, as described for the conveyance of asbestos in the following example.

Example IV Still another type of flexible, lightweight, fireproof, insulating fabric can be produced in which asbestos fibres are bonded by glass filaments in the apparatus of Fig. 3, the rotors being constructed of the same heat resistant materials and traveling at the same speed as those described in Example I.

The asbestos fibres 55B are conveyed on a belt 51 and uniformly distributed over a rotor consisting of a foraminous drum 53 of 100 mesh, which rotates about stationary arms 54, 55, 56 and 57. These arms enclose suction chambers 59 and 60, and thereby maintain the fibres on the periphery of the drum until blasted therefrom by heated air or steam pressure from chamber 63.

Small, discrete particles of fibre-forming glass 67, such as from 100 to 200 mesh, are charged into the hopper 68 and fed as required by rotary valve 69 through pipe '70 to the burner 71, which is supplied by fuel under pressure by pipe 72 from a source not shown. The blast of burning fuel reduces the discrete particles of glass to a fibreforming fluidity at a temperature about 1900 F., and in that condition they are deposited on the peripheral surface and in the pockets of rotor 65; or the particles, if deposited in a solid condition, will adhere to and be reduced to fibre-forming fluidity by the rotor heated to about 2100 F. from a jet flame or other suitable means. The molten glass in either case is scraped by a spring pressured blade 73 into the pockets 66, and the excess is removed entirely from the rotor and drained through outlet 75.

Converging paths of the two rotors bring the discrete asbestos fibres andthe pockets filled with fibre-forming glass into adhesive contact, and their diverging paths cause the glass in their respective reservoirs to neck down into positively stretched filaments 78 untilfinally the fibres are cut off from their suction contact with the peripheral surface of the primary rotor and blasted therefrom by heated air or steam pressure within the pressure chamber 63. The blast gives the fibres a theoretical initial velocity of at least 7500 feet per minute and the pull exerted on the fibres, to which they are adhesively connected, produce filaments '79 from 2 to 20 feet in length, both of which are then deposited on the foraminous drum 32, shown in Fig. 1. The asbestos fibres and the glass filaments are bonded together, in similar manner to that described in Example I, by a spray of a polyester resin from nozzle 45, and the resin set by heat and calendering from the roll 4-7.

Perlite, micaceous materials, Michrome alloy flakes, and other pulling solids can be conveyed in like manner by the top rotor 53 to contact adhesive glass particles conveyed by the lower rotor 65; or the glass particles can be conveyed in a solid state by belt or other means to the top rotor 53 and held in position by suction until contacted by pulling solids of higher melting point than the glass. These solids can be fed to a lower rotor, such as in Fig. 1, at a temperature of about 2100" F., and will reduce the glass particles to an adhesive and fibreforming fluidity on contact. Filaments and fabrics can be produced in either case, as already indicated.

Example V In an all glass fabric for awnings, etc., short staple glass fibres of from 2 to 4 inches in length, or even the much shorter fibres of glass fiock, are substituted for the asbestos fibres, used in the apparatus of Fig. 3 and described in Example IV.

The glass staple fibres have a softening point of 2100 R, and are deposited both on rotor 53 and finally on the collecting drum 32 in a set condition. The fibreforming glass 67, conveyor by pipe 70 from a source of supply 68 and having a softening point of 1900 F., are deposited in a fibre-forming fiuid and adhesive condition on both rotor 65 and then as filaments on the collecting drum 32. Consequently no resin is required for bonding purposes.

However, when desirable, filaments of substantial length can also be deposited in a set condition and both the pulling fibres and the said filaments bonded together by a vinyl chlorosilane vapor of a polyester resin from nozzle 45; or a cellulose acetate sheet from roll 49 can be substituted for a bonding resin and will be selfadherent, providing the deposited glass filaments are maintained at a temperature of between 350 F. and 375 F. at the time the two Webs are run together; or the nozzle 45 can be used to disperse or sift short organic thermoplastic fibres, as for instance, vinyl-chloride-acetate, vinylidene chloride, or polyamide fibres of A inch to 2 inches in length, on glass filaments deposited on the collecting drum at a temperature between 280 F. and 300 F, and the organic fibres will become adhesive and bind the inorganic filaments.

Example VI Metal foil, such as an aluminum sheet of less than .001 inch in thickness, can be reinforced by set glass filaments produced by the apparatus of Fig. 3 and described in Example V. The reinforcing filaments are deposited in intersecting relation and substantially lengthwise of the foil, or they can be deposited in an intersecting and random formation, as already described in Example I.

A polyester resin from spray nozzle 45 in Fig. 1, heat of 300 F. from the glass filaments deposited on a collecting drum, positioned in sufficiently close proximity to the muzzle of the spinning barrel to maintain this heat, and pressure from the calender roll 47, will bond the glass filaments to the foil from roll 49. The filaments need not exceed the thickness of the foil to give the latter sufiicient strength for most purposes.

Obviously, the tear strength of thin transparent films, such as vinylidene chloride, vinyl-chloride-acetate and the like of .001 to .0001 inch in thickness, can be greatly increased by being reinforced in similar manner. In such cases, the glass filaments are deposited at the adhesixe temperatures of the films, usually between 200 F. and 300 F., and the film from roll 49 bonded to the glass filaments by heat of the latter and pressure from calender roll 47.

Example VII in the construction of building material, particularly roofing and siding, and similar waterproof, weather-resistant articles, the sheeting is reinforced by glass filaments in somewhat similar manner to the reinforcing of aluminum foil in Example VI.

Molten glass is distributed over a rotor 65, as shown in Fig. 3. The scraper or doctor blade 73 is adjusted to permit the rotor to carry the molten glass in uniformly spaced pockets, or as a film coating if no pockets are used, into contact with pulling solids distributed over the top rotor from the belt 50; and to make a sheeting of paper stock saturated with bituminous material more resistant to weathering conditions Or increase its insulation value, exfoliated micaceous material, expanded perlite, asbestos, Nichrome alloy flakes, or staple glass fibres are used, as already indicated, for the pulling solids.

Cementing asphalt or tar having a softening temperature between 220 F. and 250 F. is sprayed from nozzle 45 at a temperature of about 400 F. to bond the deposited set glass filaments and pulling solids into a fabric, and also to bond 2. bituminous, impregnated felt from roll 40 to the fabric, which bonding is aided by the calender roll 47. If the collecting drum is adjusted to the mouth of the spinning gun so that the filaments are deposited at a temperature of about 400 F., the heat of the latter will be sufficient to soften the bituminous sheeting and cause it to adhere to and bond the filaments and pulling solids without the aid of additional adhesive.

However, a preferred method to make roofing and siding is to use the fabrics of Examples I to V as a base, and then impregnate them with bituminous material from nozzle 45 in which may be incorporated metallic fiakes, such as aluminum, bronze, etc., and calender the fabric to form a felt. Or finely divided dry asphalt may be sifted over the glass fabric by nozzle 45, and the bonding accomplished by heat and pressure from the calender roll 47. To prevent sticking when the fabric is wound into rolls, one side is powdered with talc, silica dust, or the like, or given a paper backing before calendering, as in prior practice.

If light weight pulling solids are used, such as vermiculite, perlite, glass fibres, or asbestos, the amount of bitumen impregnant required to waterproof the base fabric will usually vary between 50 and per cent of the weight of the latter, and the total weight of the impregnated fabric between 10 and 30 ounces per square yard, but of course these figures may vary within wide limits depending on the thickness of the fabric required.

To bond the sheets together and to a roof decking or other surface in structural Work, a brush coating of a solvent for the bitumen impregnant in the felt will enable the treated sides of the layers to be cemented together and to the receiving surface as the fabric is laid down. The solvent may be volatile, such as petrol; or it may be nonvolatile, such as creosote.

Example VIII Fabrics for roofing, siding and the like can also be produced by stretching the filaments by centrifugal propulsion of the pellets.

This is accomplished by increasing the peripheral speed of the rotors, as for instance to 3,000 feet per minute, and spreading the arms 56 and 57 of Fig. 3 to limit the arc of the suction chamber 60 to that point at which the peripheries of the rotors begin to diverge in their rotative movements.

The above speed results in the pellets being thrown off the periphery of its rotor by centrifugal force as soon as they are carried beyond the suction chamber 60. The pellets strike the upper wall of the stretching barrel and about the same time the filaments are severed from the lower rotor thus producing filaments of substantial length. The blast from pressure connection 64 carries both filaments and pulling solids out of the barrel and results in their deposition on the collecting drum 32 where the solids with attached filaments are bonded together by a polyester vapor spray from nozzle 45.

All of the discrete pulling solids described in the foregoing examples can be thrown off by centrifugal force. However, when light weight pulling solids, such as vermiculite, perlite, glass, and asbestos fibres are used, a greater length of filaments can be obtained by using a high velocity conveying fluid in conjunction with centrifugal action, and particularly is a higher blast desirable when the pulling solids are to remain attached to the filaments without disintegration of the former by impact, or explosion of the solids on release of the blast pressure by exit from the stretching barrel.

While several specific examples have been given above describing how filaments and fabrics can be produced from, or fabrics reinforced by, glass, it is obvious that the present invention can be successfully employed in the production of filaments and fabrics from many types of organic and inorganic materials which become softened and fibre-forming in the presence of heat, and that there may be many modifications to these examples.

Glass filaments described above, also films, foils, and fabrics reinforced by them, will usually have a thickness which varies between .01 inch and .001 inch in thickness, but both filaments and foils may be much thinner or heavier than these figures indicate. The final diameter of the filaments can be controlled by regulating the size of the rotor reservoirs or rate of flow of glass threads or film coating upon a rotor, the speed of the rotors, the velocity of the pulling pellet blast, and the size and weight of the pellets.

The fibre-forming material can be deposited on a primary rotor in uniformly spaced or uniformly distributed discrete solid portions, and the solids reduced to fibreforming and adhesive fluidity during rotation of the rotor, to contact uniformly spaced or uniformly distributed pulling solids on a secondary rotor; it can be deposited on a primary rotor in uniformly spaced fibre-forming fluid and adhesive portions, or uniformly distributed fibre-forming adhesive threads or film coatings, to contact uniformly spaced or uniformly distributed pulling solids on a secondary rotor.

It will also be evident that if the peripheral speed of the collecting drum or belt is greater than that of the outer ends of the filaments just before their deposition, the filaments will be deposited substantially lengthwise of the fabric, and the ends of the filaments from each axial row of reservoirs in a rotor will overlap substantially uniformly a succeeding set of filaments; when the said peripheral speed is less than that of the outer ends of the filaments just before deposition, the filaments will be deposited in random formation and will bond the pulling solids in that manner.

It will again be evident that the porosity of the fabrics described above can easily be regulated by adjusting the size and kind of filaments and pulling solids, and the amount and penetration of the bonding agent, to suit the purpose for which the fabrics are to be used.

It will furthermore be evident that insulating fabrics of asbestos, perlite, metallic flakes, micaceous minerals, or staple glass fibres, bonded by glass filaments of substantial length can all be molded in accordance with the method described in my copending application, Serial No. 365,849, filed July 3, 1953. Fabrics of glass filaments ordinarily are truly elastic up to a stretch of 3 per cent of their length and can be molded at this stretch, providing the fabric is previously impregnated with a polyester or other suitable resin and the resin set before release of the article from the molds. If a greater stretch is required, glass filaments of substantial length must be broken during the molding operation if comparatively low temperatures are to be used.

I claim as my invention:

1. In a method for attenuating a fibre-forming material into filaments by the propulsion of discrete solid material adherent therewith, the steps comprising: dispersing one of the said materials in a gaseous stream; directing the said stream against a supporting wall to deposit the said one material thereupon; moving the said wall through an endless circuit to bring the said materials into adherent contact in a predetermined relation; and propelling the said solid material from the said wall with an adherent portion of the said fibre-forming material to produce a continuous succession of discontinuous filaments.

2. In the method of claim 1, the said steps in which the said one material is the fibre-forming material, and the said gaseous stream is heated to reduce the said one material to a molten condition of fibre-forming fluidity.

3. In the method of claim 2, the said steps in which the said deposition of the said molten material forms an integral coating over the said wall.

4. In the method of claim 3, the said steps in which the said adherent contact of the solid material is made only with predetermined portions of the said coating.

5. In the method of claim 3, the said steps in which the said wall has pockets therein, and including the step of removing a portion of the said coating in such a way that the said pockets are filled with discrete divisions of the said molten material, and the said contact is made only between the said divisions and the said solid material.

6. In a method for making a nonwoven fabric, the said steps of claim 1 for producing the filaments, and including the additional steps: depositing the said filaments upon a fibre-retaining wall; moving the fibre-retaining wall through an endless circuit and simultaneously and relatively reciprocating one of the said walls to cause the said filaments to intersect and extend beyond one another in a succession of overlaps.

7. In the method of claim 6, the said steps in which the said solid material is bonded into the said fabric in predetermined relation to and by the said filaments.

8. In a method of making roofing and siding, the said steps of claim 7 for producing a fabric, and including the step of impregnating the said fabric with a bituminous saturant.

9. In an apparatus for attenuating fibre-forming material into filaments by the propulsion of discrete solid material adherent therewith, the combination of: a supporting wall; an enclosure for the said wall; a propulsion barrel attached to the aid enclosure; means for dispersing solid particles of one of the said materials in a gaseous atmosphere within the said enclosure and depositing the particles upon the said wall; means for moving the said wall through an endles circuit to bring predetermined divisions of the said materials into adherent contact; and means for propelling the said solid material with adherent portions of the said divisions of fibre-forming material away from the said wall and through the said barrel.

10. In the apparatus of claim 9, the said combination in which the said wall has pockets therein, and including means cooperating with the said movement of the wall whereby the said pockets are charged with the said divisions of one of the said materials.

11. In the apparatus of claim 9, the said combinations in which the said wall is a primary wall, and the said propelling means include: a secondary wall to propel the said solid material with the said adherent portions from the said primary wall; and means adjacent to the 11 12 said secondary Wall to propel the said solid material with References Cited in the file of this patent the said adherent portions from the secondary wall and UNITED STATES PATENTS through the said barrel.

12. In the apparatus of claim 9, the said combination 2,057,167 Sherman 13, 1936 in which the said particles are particles of the said fibre- 5 2,172,048 Johnson P 1939 forming material, and the said dispersion means is a 2,266,761 Jackson et a1 23,1941 gaseous blast of sufiiciently high temperature to reduce 2,649,394 Allg- 18, 1953 the said particles to fibre-forming fluidity during the 2587363 Manmng 1954 said dispersion and deposition, and including means for 2,689,199 Peso? P 1954 feeding the said particles into the said blast. 10 2,697,056 Schwartz 1954' 13. In the apparatus of claim 9, the said combination 713,001 Mannmg July 1955 in which the said propelling means includes centrifugal force.

Claims (2)

1. IN A METHOD FOR ATTENUATING A FIBER-FORMING MATERIAL INTO FILAMENTS BY THE PROPULSION OF DISCRETE SOLID MATERIAL ADHERENT THEREWITH, THE STEPS COMPRISING: DISPERING ONE OF THE SAID MATERIAL IN A GASEOUS STREAM; DIRECTING THE SAID STREAM AGAINST A SUPPORTING WALL TO DEPOSIT THE SAID ONE MATERIAL THEREUPON; MOVING THE SAID WALL THROUGH AN ENDLESS CIRCUIT TO BRING THE SAID MATERIALS IN ADHERENT CONTACT IN A PREDETERMINED RELATION: AND PROPELLING THE SAID SOLID MATERIAL FROM THE SAID WALL WITH AN ADHERENT PORTION OF THE SAID FIBRE-FORMING MATERIAL TO PRODUCE A CONTINUOUS SUCCESSION OF DISCONTINUOUS FILAMENTS.

6. IN A METHOD FOR MAKING A NONWOVEN FABRIC, THE SAID STEPS OF CLAIM 1 FOR PRODUCING THE FILAMENTS, AND INCLUDING THE ADDITIONAL STEPS: DEPOSITING THE SAID FILAMENTS UPON A FIBRE-RETAINING WALL: MOVING THE FIBRE-RETAINING WALL THROUGH AN ENDLESS CIRCUIT AND SIMULTANEOUSLY AND RELATIVELY RECIPROCATING ONE OF THE SAID WALLS TO CAUSE THE SAID FILAMENTS TO INTERSECT AND EXTEND BEYOND ONE ANOTHER IN A SUCCESSION OF OVERLAPS.

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