US2888375A - Gas plating blown glass fibers - Google Patents

Description

y 1959 F. E. DRUMMOND 2,888,375

GAS PLATING BLOWN GLASS FIBERS Filed Sept. 27. 1954 GASEOUS METAL CARBONYL' GENERATOR INVENTOR #04. saw 5. URUMMONO jg i1 ATTORNEYS United States Patent GAS PLATIN G BLOWN GLASS FIBERS Folsom E. Drnmmond, Washington, D.C., assignor to The Commonwealth Engineering Company of Ohio, Dayton, Ohio, a corporation of Ohio Application September 27, 1954, Serial No. 458,510

1 Claim. (Cl. 154-101) This invention relates to an apparatus and method for producing metal coated fibers, and more particularlyv to a method and apparatus for producing fibers in bulk foim and wherein the individual fibers have an outer coating of metal, the metal-coated fibers being subsequently matted or felted together to provide a metalized fibrous product which may be fabricated into different shape.

Methods and apparatus have been proposed heretofore for forming filaments and fibers and then subjecting the same to gaseous metal plating to coat the individual strands or filaments with metal, but such processes and apparatus have not been applicable for metal coating the fibers in bulk form.

The present invention provides a method and apparatus for metal coating fibers in the bulk, and such as may be produced, for example, by contacting heated filaments as drawn from a molten or extruded mass with a hot gaseous flame blast, whereby the filaments which are moved into the path of the blast are simultaneously melted and drawn out and disintegrated by the force of the blast into fine fibers of short length. Such a method is conventionally employed to produce fine, staple glass fibers. Similar methods are used to produce fine synthetic organic fibers.

It is an object of the invention to provide an apparatus and method of producing metal coated fibers of the character described and wherein the heat produced during melting, blowing and/or attenuating of the fibers is utilized to effect the decomposition of the gaseous metal compounds or mixtures of compounds employed to efiect the metal deposition.

Another object of. the invention is to produce a fibrous mass made up of fine fibers of short length which fibers are collected in bulk form in a chamber and subjected to gaseous metal plating while thus confined.

Another object of the invention is to provide a fibrous mass wherein the individual fibers are coated with metal in the bulk and the resultant metal plated fibers pressed together or molded to form an article of the desired shape, the fibers being bound together by the metal coating and without the use of added binder.

Another object of the invention is to provide a fiber mass formed by tearing or disintegrating filaments made of the fiber-forming material into short-length fibers which are conveyed or blown into a collecting chamber and then subjected to gaseous metal plating in the bulk to cause metal to be deposited onto the fibers.

Although the invention will be particularly described with respect to the production of fine or staple fibersv formed of glass, siliceous slags and the like mineral substances, it will be understood that the invention is also applicable for metal plating of organic fibers as aforementioned, and wherein the fibers are capable of being heated sufiiciently high to effect gaseous metal plating, for example fibers made of synthetic resins, paper, wood, cotton, wool and the like.

The invention is readily adapted for metalizing glass fib in bulk a d, su sp o ucs by m t ng nd 6X:

2,888,375 Patented May 26, 1958 truding primary glass filaments which are attenuated and moved lengthwise across a hot flame blast to cause the heated glass filaments to be further attenuated and disintegrated into very fine glass fibers.

The resultant hot glass fibers are collected and While hot subjected to an atmosphere containing gaseous metal which is heat decomposable at the temperatures .of the fibers. The mass of glass fibers while floating about in the chamber are thus coated with metal. The gaseous metal compound or mixture of metal compounds utilized in each case being selected to provide the desired metal coating.

Where the fibers are formed of molten slag, glass or the like, as mineral wool and without attenuation of the fibers, filaments formed of the molten material are blown into fibers and collected in a chamber and the fibrous bulk subjected to gaseous metal plating similarly as with fine glass fibers.

To more particularly describe the apparatus and method of metal coating fibers in accordance with this invention, one embodiment is illustrated and described for the production of fine glass fibers coated with metal.

In the drawings:

Figure 1 illustrates an apparatus and method of producing fine, staple glass fibers which are gaseous metal coated and recovered as a compacted sheet, the drawing illustrating diagrammatically in elevation a suitable apparatus for making the same; i

Figure 2 illustrates a modification of the apparatus shown in Figure 1, for blowing the filaments into fibers prior to gaseous metal plating, the view being fragmentary and a diagrammatic illustration; 4

Figure 3 illustrates diagrammatically a further modification of the apparatus of Figure 1 wherein means is provided for the introduction of binder onto the fibers after the same have been gas plated to produce metal plated fibers which may be bound together by a thermosetting binder.

Referring to the drawing in detail, Figure 1 illustrates an embodiment for producing fine, staple glass fibers coated with metal. As illustrated, a hopper is provided as at 10 for containing solid glass stock 12 to be melted. The glass stock is made of any desired composition, e.g., a borosilicate glass, alkali metal silicate or the like, depending upon the type of fiber desired. The hopper 10 is provided with a slidable gate or door 14 which is preferably electrically operated by means of a solenoid 16. Intermittent introduction of glass stock 12 into the heating receptacle or melting pot- 17 positioned therebeneath, as required, isthus provided.

The melting pot 17 is preferably cylindrical in cross section and comprises a hollow shell or surrounding jacket 18 in which is disposed heating elements such as, electrical resistance coils 20 for heating the melting pot to provide a reservoir of molten glass 22 in the melting pot 17. A closure mold 24 arranged in the bottom of the melting pot comprises a plurality of circumferential ly spaced orifices 26, for extruding glass filaments 28. The glass filaments 28, which may be extruded under" pressure or by gravity, upon congealing, are engaged bythe friction rolls 30 and the heated fibers are attenuated into fine filaments, then passed from the rolls overa; guide plate 32 and directly across a blasting fiameburner nozzle 34. v

The blast delivered from the nozzle 34 is preferably.- of high velocity and high temperature. The heat of the blast melts the filaments of glass and as it melts isdrawn out into a fine fiber 38 by the force of the blast. To provide a suitable hot blast flame a combustible fuel gas and air mixture, is fed to the burner nozzle 34 and the blast thus created converts the glass filaments brought contact. therewith v intofine fibers. The temperature of the blasting flame is on the order of 3000 to 3800 F. and the velocity of the heated gases discharged from the nozzle 34 is between about 1200 and 2000 feet per second. Utilizing such a high temperature high velocity blast glass fibers of one micron and sub-micron diameter are readily obtained from filaments of much greater diameter. By closely controlling the process glass fibers having a relatively uniform diameter can be produced, and which may be of a fineness of about 0.00001 to 0.00035 inch in diameter and 0.01 to 0.02 inch in length. The size of the fibers attenuated by the blasting flame may be varied by varying the diameter of the primary filaments and/or by varying the rate at which the filaments are fed to the blasting flame.

The resultant fine glass fibers formed by the blasting flame are borne by the blast to a suitable collecting receptacle or hopper 40, as illustrated in Figure 1, being directed into the funnel-shaped portion 42 and thence through the opening 43 into the hopper 40. The side walls of the hopper 40 slope downwardly as at 45 to a discharge opening 46 in the bottom. Communicating with the opening 46 is a spherical housing 48.

Arranged in the housing 48 is a rotary lock valve 50 which is in the form of a wheel having radially extending arm members 52 which are machine fit at their extremities 53 to form a seal with the inner wall of the housing 48. Glass fiber material deli ered from the hopper 46 passes through the rotary valve 50 to the gaseous plating chamber 56. The gaseous plating chamber 56 is preferably cylindrical in cross section, as illustrated in the drawing, and is arranged to be supplied by heat-decomposable gaseous metal compound as delivered from a generator 60 through the inlet pipe or conduit 62 to the nozzle 63 arranged in the bottom of the plating chamber. Heat-decomposable gaseous metal compound which is introduced through conduit 62 flows upwardly as indicated by the arrows at 64 during decomposition and plating. Waste gases and unused gaseous metal is drawn off through outlet opening 66 and through the return conduit 67 to the generator.

The chamber 56 is provided with a funnel-shaped bottom portion 68 which terminates in a discharge opening 69 which is controlled by rotary valve 70. The rotary valve 70 controls the discharge of metal coated fibers, as shown at 72, which as shown are delivered onto an endless belt 75 arranged therebeneath. Endless belt 75 is arranged to pass around the rollers 76 and 77 one or more of which are suitably driven to move the metal coated glass fiber mass 80 therealong and between the spaced rolls 81. By varying the spacing between the pressing rolls 81 a compacted sheet of metal coated glass fibers of a desired thickness may be produced as at 82, the same being moved onto a supporting table 84.

As illustrated in Figure 2, the glass filaments 85 may be extruded downwardly from the melting pot 86 and directly to the blasting flame nozzle 87 arranged in the chamber 89, whereby the filaments are melted and blown to form fine fibers as at 88. The fibers gravitate to the bottom of the chamber 8 and are passed through a rotary lock valve 90 to the gaseous metal plating chamber 92. After gas plating the same, the fibers are discharged therefrom through a rotary valve lock as illustrated in Figure 1.

In the modification shown in Figure 2, the glass fibers are not attenuated except through the blowing and force of the blasting nozzle 87. Such a modification may be used to produce mineral wool from molten slags or the like, and wherein the fibers are of larger diameter than the attenuated fine glass fibers such as may be produced using the apparatus shown in Figure 1.

In Figure 3 a modification is provided wherein a suitable binder, such as heat curable resin, sodium silicate or the like, are introduced through the spray nozzles 94 arranged in a collecting chamber 96. The gaseous metal plated fibers as delivered from the plating chamher fitt, are passed from the gaseous metal plating chamber 93 through the rotary lock valve 99 to chamber 96 where the fibers are coated with hinder, the same being sprayed thereon by the use of spray nozzles 94. Finally the fibers which are metal coated and sprayed with binder are then discharged from the receptacle 96 and may be compressed or molded and heated to cure the binder to produce a finished fibrous metal product having the desired shape.

Various organic resinous binders may be used depending upon the properties desired of the final product and the uses to which it is to be put. A binder may be used which is heat softenable and which becomes suitably plastic and tacky upon heating to permit bending and shaping of the metallic fibrous product. Materials useful for this purpose are: phenolic-aldehyde resins, gilsonite, ester gum, rosin, pitch and the like, which are normally solid at room temperature 70 F. and thermoplastic or thermo-setting when heated at higher temperatures. The binder may be introduced into the fibers as a finely divided mass or dispersed in a volatile organic solvent. After initially forming the metallic fibrous sheet mass the same may be heat-treated to immobilize or cure the binder to produce a densified product. Compressed fibrous sheet material having a density of from 1 to 100 pounds per cubic foot or more may be made depending upon the fiber and metal compounds and binder used.

If desired, the metallic fiber may be used in granular fiowable form, as for example as insulating material or the like.

In this process the metal to be plated onto the fibers in bulk is introduced into the plating zone in vapor form. This vapor may be concentrated or diluted with inert gas such as carbon dioxide, helium, etc. as delivered from the generator.

One particularly advantageous method of bringing metal as vapors into the plating zone is in the form of readily heat-decomposable gaseous compounds. For example, the metals may be introduced as gaseous metal carbonyls, also nitroxyl compounds, nitrosyl carbonyls, metal hydrides, metal alkyls, metal halides, and the like.

Catalytically active metals which may be deposited are iron, nickel, cobalt, chromium, molybdenum, tungsten, tellurium, selenium, tin, zinc and the like, or suitable mixtures thereof.

Illustrative compounds of the carbonyl type are nickel, iron, chromium, molybdenum, and cobalt.

Illustrative compounds of other groups are for example, cobalt nitrosyl carbonyl, hydrides, such as tellurium hydride, selenium hydride, antimony hydride, tin hydride, chromium hydride, and mixed organo-metallo hydrides, such as dimethyl alumino hydride, metal alkyls such as tetraethyl lead, metal halides such as chromyl chloride, and carbonyl halogens, for example osmium carbonyl bromide, ruthenium carbonyl chloride, and the like.

When the metal bearing gases are diluted such inert gases as carbon dioxide, helium, nitrogen, etc. the gaseous products are kept free of oxygen so that the gaseous metal decomposition and deposition of metal on the fibers may be achieved without interruption.

Plating may be carried out under a wide variety of conditions. When undiluted vapors are fed to the plating zone, it is generally preferable to feed the vapors under a slight positive pressure, i.e., a pressure above atmospheric. When dilute vapors are fed to the plating zone, a wide range of pressures may be used, running from negative pressures usually expressed in inches of water vacuum to positive pressures usually expressed as pounds per square inch gauge.

Each material from which metals may be plated has a temperature at which the metal in vapor form is free to deposit as a metal coating. When plating there is an optimum plating range for a large number of, for

example, metal carbonyls, running from about 350 F. to 450 F. Decomposition takes place outside this range, but when seeking uniform deposits, it is desirable to operate within the above range and even within the range of about 350 F. to 400 R, if it is desired to plate nickel, molybdenum, cobalt and the like.

The above-mentioned temperature range of 350 to 450 F. is also useful for decomposition of many of the hydrides. However, since each type of metal and each type of compound alters the plating range, applicant merely offers the above range for specific embodiments of the invention and not as a limitation upon the operating range of catalytic coating deposition.

In the operation of this equipment the fibers of material in the bulk which is already at the desired temperature for eifecting plating, for example in the range of 375 F. to 400 F. or heated thereto are continuously fed from the hopper to the gaseous plating chamber through the rotary lock valve. If leakage of gases from the plating zone is to be prevented, the hopper 40 and rotary lock valve chambers 48 and 70 may be charged with gases, e.g., carbon dioxide, under a pressure slightly higher than the pressure maintained in the plating zone.

In the gas plating chamber 56, which is maintained full of moving fragmentary fiber material, there percolates through the bed a gaseous stream of, for example, carbon dioxide and nickel carbonyl, entering through the inlet conduit 63 and being exhausted, together with the decomposition product gases, through the exhaust duct 67.

The time of passage through the cylindrical chamber is regulated by the locks 48 and 70 to a time for the deposition of the desired depth of coating. This depth of coating generally is a deposit having a thickness of about 0.0003 to 0.005 inch. Such a depth of deposit under proper conditions of gaseous feed may be placed upon the fibers in a matter of a few seconds. These coatings must be maintained within this thin coating range in order to obtain the maximum porosity which yields such increased effective surface areas per unit of volume.

In the foregoing embodiment illustrating the invention as applied to the preparation of metal coated glass fibers, it is to be understood that the process is readily applicable as aforementioned to the plating of various materials in comminuted condition and such as can be passed through the gaseous plating chamber in bulk and dispersed condition. The invention is accordingly applicable for plating comminuted paper such as confetti, and dispersed fibers such as cotton and wool lint and the like, as well as dust particles of mineral or organic origin.

It will also be understood that where the metallized fibers are desired to be used as separate pourable particles or granules the collecting and compressing of the fibers in the form of a sheet may be dispensed with and the metallized fibers or material may be collected for use as discharged from the gaseous metal plating chamber.

The apparatus and method as disclosed and described herein and constituting one embodiment of the invention it will be understood may be modified and varied to suit different conditions and uses to which the article is to be put, and the method resulting from the operation and utilization of the apparatus is capable of variations and substitutions without departing from the spirit and scope of the invention and that all modifications that fall within the scope of the appended claim are intended to be included herein.

What is claimed is:

A method of producing metallized glass fibers which comprises the steps of feeding siliceous stock into a heating chamber having a plurality of apertures in the bottom wall thereof, heating said stock within the chamher to form a melted mass, extruding the melted mass from the apertures to form a plurality of filaments, directing a hot flame blast against said filaments to break up and disintegrate the same into short fine hot fibers, thereafter immediately collecting and transferring the resultant hot fibers into a plating enclosure, agitating the fibers by directing a current of gas upwardly through the mass of fibers, and subjecting said glass fibers while still hot to gaseous metal plating by contacting the mass of hot fibers and while being agitated to gas plating by contacting the hot fibers with a gaseous metal bearing compound which is heat-decomposable at the temperature of said fibers to cause decomposition of said gaseous metal compound and deposition of the metal constituent onto said fibers in the form of a very thin coating to produce a free-flowing mass of metallized fibers, said glass fibers being subjected to gas plating in said enclosure while the individual fibers are circulated about by an upward flow of said current of gas and while the said hot fibers are in motion and floating about in said gas plating chamber, spraying a thermo-curing resin binder onto said metallized fibers, and then depositing the resultant mass on an endless support and roller compressing the resultant mass of metallized fibers and binder into an elongated sheet and thereafter heating the same to cure and set the binder.

References Cited in the file of this patent UNITED STATES PATENTS 2,616,165 Brennan Nov. 4, 1952 2,647,851 Schwartz Aug. 4, 1953 2,663,906 Labino Dec. 29, 1953 2,699,415 Nachtman Jan. 11, 1955 2,701,901 Pawlyk Feb. 15, 1955 2,758,952 Toulmin Aug. 14, 1956

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