US2433000A - Method for the production of filaments and fabrics from fluids - Google Patents

Description

Dec. 23, 1947. F. w. MANNING )METHOD FOR THE PRODUCTION OF FILAMENTS AND FABRICS FROM FLUIOS Filed Sept. 29, 1945 Hum I.. wm. WN N .Mn www mah NL' mm, Numb/vl.

w. a im Patented Dec. 23, 1947 UNITED STATES PATENT oFFlcE METHOD FOR THE PRODUCTION OF FILA- MENTS AND FABRICS FROM FLUIDS Fred w. Manning, relu Alto, cam.

Application September 29, 1943, Serial No. 504,524

, 423.733,. subsequently issued as Patents Nos.

2,336,743, 2,336,744, and 2,336,745, respectively.

Prior practice has been to limit the use of spray guns to the disruption of substances into droplets, which were projected against surfaces where they flattened out into overlapping scales and then became indurated into hardened coverings, but as far as I am aware, no attempt has ever been made to use a spray gun to attenuate a fluid into a plurality of filaments, and disperse and deposit the filaments to form a non-woven fabric.

It is therefore the primary object of my invention to provide an inexpensive method for disrupting a fluid into a plurality of filaments, and projecting the filaments in an adhesive state upon the object to be coated or covered by intersectlng filaments. 'Such a non-woven fabric can then be sprayed by droplets to form a film thereover, which coating may cover the filaments alone to protect the latter and leave the fabric pervious, or the film may also cover the interstices and leave the fabric impervious, or the film covering for filaments and/or interstices may leave the fabric pervious to certain fluids and impervious to other uids. These composite fabrics may then be sprayed by treating fluids or solids in finely divided form.

In accordance with my invention, I propose to use spinning materials which are usually thermoplastic but may be thermosetting. A great variety of plastics may be used for as many different purposes, such asvinylidene chloride, vinyl chloride acetate, polyvinyl chloride, polyvinyl butyral, polystyrene, polyvinyl acetate, methyl methacrylate, and polymeric amide resins, ureaformaldehyde and phenol-formaldehyde compounds, latex compositions, cellulosic and petroleum derivatives, protein-base materials, glass, mixtures of organic and inorganic materials, and almost all materials that are now spun or extruded into lments, films and foils. These materials may be reduced to a fluid condition by means of solvents, pressure, heat, or any combination of these three treatments. Acetone may be used as a solvent for cellulose acetate, phenol and formic acid for a polymeric amide,

toluene for a copolymer of vinyl acetate andv 3 Claims. (Cl. 154-101.)

4 Vusually prefer to reduce a plastic to a fluid state water from the spun filaments.

by heat treatment, with or without a moderate amount of solvent to lower the softening point of the plastic, or else by using a solvent that is very cheap. Preferred solutions for'many purposes are aqueous l solutions of polymerized vinyl alcohol. The amount of polyvinyl alcohol required in a water solution for spinning purposes may be as low as 5 per cent by weight, or it may be as much as 25 per cent, or more, and a small amount of acetone, alcohol, etc., may be added to the solution to speed the evaporation of the The solution may be heated to the boiling point o f water in an open vessel, or a4 much higher temperature under pressure in a closed container, and during the spinning of the filaments the latter may be subjected to a blast of hot air to hasten the evaporation of the water.

An elastic or liquid fluid blast or stream may be used in the gun for disrupting a plastic fluid into a plurality of filaments, and may envelop, or be positioned adjacent to, the filaments to propel them at a much greater speed than their extrusion speed in order to attenuate the filaments and orient their molecular structure. A secondary fluid blast or stream may envelop, or be positioned adjacent to, the first and travel at a still greater velocity to give the filaments additional stretch or accelerate the stretching operation, and either or both may be also used for conveyance, induration, dispersion, disruption, and deposition, of the filaments. Heated air, or superheated or saturated steam, may be used for maintaining the filaments in a plastic condition until deposited, or vfor removing a volatile solvent from the filaments before or/and after deposition; cold air, a cold water spray carried by an elastic fluid, or a cold water stream, may be used for quenching or shrinking the laments during conveyance or after deposition,

and for other induration purposes; non-oxidizing fluids, such as helium, nitrogen, hydrogen, argon, or carbon dioxide, may be used where oxidation tendsto discolor or decompose the filaments; and any of the above fluids may be used to convey treating agents in a finely divided form, such as adhesives or solvents to bond indurated filaments together, pigments to color the filaments, water repellents, fire retardants, wetting agents, lacquers, etc.

Any pressure fluid for the above mentioned purposes may also be used to actuate a motor for driving a centrifuge or other mechanism to speed up the operations for which treating fluids are used, such as the disruption of a. plastic i'iuid into a plurality of nlaments, stretching of the laments, etc. The spinning material may be fed into a centrifuge through a rotating shaft that connects the motor to the centrifuge, or through a fixed tube within the rotating shaft, or through a tube positioned externally of the shaft. The disruption of the material by centrifugal force through suitable openings in the perimeter of the centrifuge, which may be aided by a primary blast or stream of elastic or liquid fluid intermixed with the filaments, will result in rapidly whirling filaments within deecting walls that will change the spiralling movement of the filaments to a helicoidal movement directed toward the object to be covered; or the spirallng of the filaments with or without the aid of the primary blast or stream may be changed to an advancing helicoidal movement by an enveloping secondary stream of an elastic or liquid fluid, directed toward the object to be covered and lin the same controlled path. And, of course, 'the plastic fluid may be disrupted into filaments through openings in an extrusion device by a pressure differential, and the filaments propelled through a controlled path and deposited by either, or both, primary and secondary conveying fluids without aid of centrifugal force. The length of the filaments at deposition will depend on the extent they are subjected to opposing forces during conveyance and stretching, kind of plastic, etc. 'Ihey may be stretched and .deposited in substantially continuous lengths and in a uniformly intersected condition, with or without aid from the conveying iluids,by reciprocating, rotative, or other regular movements of either or both gun and object being coated; or they may be deposited in broken lengths in a promiscuously intersected condition, in which case the actual lengths of the laments in an integral fabric will seldom be apparent.

Any suitable means may be utilized to create the differential pressure required to feed the plastic iiuid from a supply container to the centrifuge, such as fluid pressure exerted within the, container, or withdrawal of atmospheric pressure ning operation will cause bubbles to form within the filaments.

The invention is exemplified in the following description, and a preferred arrangement is illustrated by way of example in the accompanying drawings, in which:

Figure 1 is a vertical section of a spinning gun.

Figure 2 is a cross-section taken on line 2-2 of the gun.

Figure 3 is an elevation view of the end of the spinning gun and a retaining wall for the spun which are threaded into the stock: and between the two is an annular shaft 4, which is driven I by a rotor or turbine 5 and .supported by the ball bearings .8 and l; and the latter are enclosed within a tube 8 that is concentric with the gun barrel and spaced therefrom by means of ribs 9 to allow for escape of the exhaust from the rotor. A heating element I0, which is placed between mica tubes I l and I2 and enclosed within another tube I3, surrounds the barrel, and the temperature of the element is regulated by the thermostat i4. The inner conical portion It of the extrusion nozzle or centrifuge is adjustable on the end of the turbine shaft in order that the conical portion I6 of the tube I1 may be used to regulate the air blast to the centrifuge; and both portions of the centrifuge are united by radial ribs i8, the spacing of which determines the area of the plastic streams thrown oif by centrifugal force. Air pressure from any suitable source of supply enters the stock at i9, and the flow of air to duct 20 is controlled by valve 2|, which is held in normal closed position by a spring 22 and plug Z3, the valve being operated by a, trigger 213 supported on a pin 25. The supply of air through duct 26 to the chamber 2l is regulated by an adjusting screw 28 within the packing nut 29; the air supplyy from the chamber to the centrifuge is regulated by adjustment of the latter on the turbine shaft, as mentioned above; and the air supply from the chamber to the turbine is regulated by an adjusting screw 30 within the packing nut 3l, the latter screw controlling an opening 32 placed at a, suitable angle for driving the buckets or blades of the turbine. The solution is held in container 33, which is connected to the feed tube'by container cap 36, lock nut 35, fitting 36, and passage 31, the latter being regulated by an adjusting screw 38 within the packing nut 39. An electric wire enters the gun stock at 40, and makes the circuit to the thermostat and heating element through ducts 4I, d2 and 43. A pressure uid may be applied to the container through pipe connection M.

Figure 3 shows a basket of fruit 55, over which is spun a web 46 of promiscuously intersecting filaments, the mesh being sufficiently fine and transparent to prevent infiltration of dust particles while permitting respiration and inspection. And, as indicated above, such a covering may be sprayed with a suitable impregnant to make the former impervious to moisture, as when the former is spun over a gun.

The operation of the apparatus thus described has been in part indicated in connection with the foregoing description. The rapid rotation of an extrusion device will always tend to whirl the filaments at right angles to the axis of rotation, unless the filaments are diverted by defiecting walls or movement of a fluid in an opposing direction. In the above illustration, the spinning fluid is conveyed by a differential pressure through a stationary feed tube into a centrifuge and there disrupted and conveyed by the joint action of centrifugal force and a blast of elastic fluid moving both spirally and helically between defiecting walls until finally the laments are carried into the path of the exhaust fluid from the motor, upon which both fiuids unite and are directed through the gun barrel for dispersion and deposition purposes. If maximum stretch is required for the filaments, not only should the velocity of the conveying fluids be high, but both extrusion tube Il and gun barrel 2 should be of substantial length as from one to six feet; if little stretch is required, the gun barrel must project at least a short distance beyond the point at which the filaments are thrown from the centrifuge in order that a, controlled path be provided for directing the deposition of the filaments.

If thev spinning solution is fed through an extrusion device at room temperature, the heating element may be used to raise the temperature of the motor exhaust iluidin order that the latter may remove more effectively the solvent from the extruded laments, prevent adherence of the filaments to the gun barrel, etc.; if the solution is fed through the extrusion device in a heated condition and the filaments are required to be cold drawn, a quenching or shrinking iluid, such as cold air, cold water, cold oil, etc., may be used to drive the motor and stretch the filaments, in which case the heating element may or may not be required.

A partial indurat'ion of the filaments will take place within the gun barrel, but it is usually desirable that the filaments be deposited in a sufficiently plastic state to adhere to one another in an intersected condition upon deposition to form an integral fabric, and the induration be completed thereafter. However, it will be obvious that they can also be deposited in a hardened and discrete condition, and 'the bonding be accomplished simultaneously with deposition, or thereafter, by an adhesive or solvent spray from another gun.

It will also be evident that hot or cold liquids may be substituted for elastic iiuids for coagulating, stretching, conveying, and depositing the filaments, and also to provide an actuating force for driving the motor. However, dry spinning elastic uids will usually be found preferable for most purposes, and induration can be speeded and the stretching increased by a rapid whirling of the illaments before deposition. which may be accomplished by whirling them in spirals and then in helices, or the two movements may be combined as a resultant of opposing forces.

I claim:

1. The method of producing anon-woven fabric comprising: disrupting a plastic material into a plurality of filaments by the joint action o! centrifugal force and a blast 'of an elastic Primary fluid moving at a'given speed; enclosing the said filaments and said primary fluid within a concentric blast oi an elastic secondary fluid moving at a greater than the said given speed; maintaining the'said fluids in a uniformly heated condition during the said movements: and depositing comprising: disrupting a plastic material into a plurality of filaments by the joint action of centrifugal force and a. blast of' elastic primary fluid moving at a given speed; enclosing the said laments and said primary fluid within a propelling blast of an elastic secondary uid moving at a greater speed than the said given speed; maintaining the said fluids in a uniformly heated condition during the said movements; and depositing the said laments, while sufficiently plastic to adhere to one another, upon a retaining wall in such a manner as to cause the iilaments to intersect and unite into an integral web.

3. 'I'he method of producing a non-woven fabric comprising: disrupting av plastic material into a plurality of filaments by the joint action of centrifugal force and a blast of elastic primary fluid; enclosing the said laments and said primary fluid within a, concentric blast of a uniformly heated elastic secondary uid; projecting the said filaments by the propelling actionof the two said fluids so as to deposit the laments, while sumciently plastic to adhere to one another, upon a retaining wall in such a manner as to cause the filaments to intersect and'unite into an integral web.

FRED W. MANNING.

REFERENCES CITED The following references are of record in the me of this patent:

UNITED STATES PATENTS Hooper July 8, 1924

Images