US2910383A - Method for producing filamentary material - Google Patents

Description

Oct. 27, 1959 w. H. MILLER ETAL 2,910,383

METHOD FOR PRODUCING FILAMENTARY MATERIAL Filed June 3, 1957 2 Sheets-Sheet l 9- .6 W N v H m I- =v 0 O INVENTORS,

WILLIAM H. MILLER, I o o MARCEL R. ALEXANDER, DECEASED, BY JEANNE E.ALEXANDER, ADMINISTRATRIX) Q BY Oct. 27, 1959 w. H. MILLER ET AL 2,910,333

METHOD FOR PRODUCING FILAMENTARY MATERIAL Filed June 5. 1957 2 Sheets-Sheet 2 INVENTORS,

WILLIAM H. MILLER, MARCEL R. ALEXANDER, DECEASED, BY JEANNE E. ALEXANDER,ADMINISTRATRIX ATTYS.

United States Patent Ofiice 2,910,383 Patented Oct. 27, 1959 lVIETHOD FOR PRODUCING FILAlWENTAtRY MATERIAL William H. Miller, Chepachet, R.I., and Marcel R. Alexander, deceased, late of Central Falls, R.I., by Jeanne E. Alexander, now Jeanne Beretta, administratrix, Central Falls, R.I., assignors to Owens-Corning Fiberglas Corporation, Toledo, Ohio, a corporation of Delaware Application June 3, 1957, Serial No. 663,211 7 Claims. (Cl. 117--102) The present invention relates to a method and means for producing a filamentary material comprising the combination of fluid material capable of controlled solidification, and continuous fibers of materials of glass or the like. More particularly the invention relates to a method for producing a composite filamentary form of a combination of heat settable resin and a plurality of fine continuous filaments of high strength material to reinforce the resin.

A number of methods are known for producing monofilamentary strands reinforced with fine continuous fibers, but in general, difliculties exist with each to the extent that none of the methods are known which completely overcome all the difliculties. One problem is that of providing a full coating for strands with given apparatus at a sufficiently high velocity as to make its production economical. Another is that of producing a monofilamentary material in a small space regardless of the fact that application and setting of the material incorporated therein for production economy must be produced at extremely high speeds. In general, the more rapidly a strand of this type is produced, the greater are the space requirements.

Still another problem is that of maintaining the fine filaments desired to be coated under low tension to the extent that fuzz does not develop by reason of filament breakage. A further problem is that of uniformly dis tributing the filamentary reinforcing fibers through the cross section of a composite monofilamentary form, to cause themto provide the greatest reinforcing strength obtainable from such fibers.

In viewof the foregoing, it is a principal object-of this invention to provide an economical high-speed method for producing monofilamentary material of coated reinforcingfibers which lends itself to accomplishment within a small space.

- It is another object of the present invention to provide a new high-speed method for coating continuous fibrous yarns at extremely high speeds to produce a continuous monofilamentary strand principally of the coating material reinforced by the fibers, with the surface of the strand being smoothly uniform without presence of streaks of thereinforcing fibers at the surface.

It is still another object of the present invention to provide a method for coating strands or yarns of a plurality of continuous filaments with resinous coating material, the methodlending itself to impregnation of the plurality offibers with the coating material and also coating the exterior thereof to the extent that the coat ing material forms a matrix within which the reinforcing material is uniformly distributed.

A still further object of the invention is to provide a methodfor coating a plurality of filaments of extremely fine dimension without need for tension within the filamentssuch that they might break out during the coating operation. a

A further object of the invention is to provide a method for coating a plurality of extremely fine continuous filaments by passage thereof through a die in the form of a strand under relatively low tension, and in a manner such that practically negligible lateral forces are exerted on the filaments on passage through the die so as to simulate as closely as possible a floating die, thereby minimizing tendencies toward Wiping of the coating material to the bare filaments.

in brief, the present invention involves the coating of continuous filaments by pouring coating material directly on the strand formedzthereby just prior to passage of the strand through a die but prior to passage through the die the coating fluid flowing about the strand is passed over a flat surface in out-of-contact relationship therewith to redistribute the flowing coating material for a more intimate contact of the coating material with the filaments.

Features of the present invention lie in a lack of exertion of lateral forces on the continuous filaments during passage of a strand through the die aperture which sizes the final coating on the strand, thereby effecting a more uniform full coating of filaments without streaks in the monofilamentary form produced.

Still another feature is the limited tension exerted on the filaments in the strand on passage through the dye, and also the fact that the method results in production of filamentary forms of high strength even where the material forming the matrix of the monofilamentary form may otherwise be of such nature that it would not lend itself to filamentization.

Another feature of the invention lies in the fact that fluids having a high solids content can be uniformly applied through the cross section of the filaments without fear that the solids may have settled out of the fluid prior to or during application to the strand.

A still further feature of the invention lies in the fact that by reason of the minimum exertion of lateral thrust forces on the plurality of fibers as they pass through the die, that any tendency toward compaction thereof in the die would be uniformly applied from all sides of the group of filaments so that a circular incongruous configuration is produced in the final mono- The foregoing as well as other objects and features of this invention will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings wherein:

Figure l is a simplified view in elevation ofa production line designed to carry out the 'process of the invention for the production of a filamentary material;

Figure 2 is an enlarged, partially cut-away view, in perspective, of the coating unit in the production line of Figure 1;

Figure 3 is an enlarged somewhat schematic and partly cross sectioned side elevational View of the, coating com ponents of Figure 2 illustrating more clearly the manner in which coating fluid is applied to a strand of filaments and its manner of distribution prior to passage through a die;

Figure 4 is a partial planview of the components of Figure 3; and t Figure 5 is a front view of a single apertured die with A a plurality of continuous filaments passing therethrough with coating material as taken on line 5 of Figure 3.

The method for fabricating filamentary material according to the present invention lends itself to forming a composite filament'of resin such as plastisol or vinyl chlorideand strands or yarns of continuous glass fibers.

Although glass filaments are chosen for illustration purposes, it Willbe apparent as the description proceeds that the invention is well adapted as well to coating of strands and production of monofilamentary forms with filaments of other materials such as nylon, cellulose, rayon, etc.

An example of the type of end product in which the filamentary material of the invention is adapted for use, insect screening may be chosen since it illustrates in its use many of the problems overcome by the material of the instant invention. V

In fabricating a filamentary material according to the present invention for purposes of producing a screen, one or a plurality of spools 11 are assembled on a creel 12 so that the strands or yarns of continuous glass fibers can be led through guide eyes 13 and 14 to the coating apparatus or unit generally indicated at 15. in the coating unit 15, each of the glass fiber strands 10 is combined with an exterior jacket of resin to form a composite having characteristics different from filaments of either the glass fibers alone or the resin alone. The combination of materials becomes a continuous monefilament 16 which is drawn through a curing or fusing oven generally indicated at 18, and then to a winding machine 22. Each of the individual filaments 16'is separately wound in the machine 22 at a constant lineal speed on its own spool 24. The winding machine 22 comprises a variable speed drive 28 for each of the spools 24-, a traversing member 27 fragmentarily indicated, which effects a lay of the filaments 16 on the spool 24, constant speed feeding wheels 29 and a tension control pulley 26. Tension in the filament 16 as it passes over the tension pulley 26 raises, or lowers the arm of the pulley 26, controlling the variable speed drive 28 to maintain the lineal speed of rotation of the spool 24, thereby compensating for the increasing diameter of the spool of filament being Wound and for other changes in speed which might occur.

Before winding the strand or filament 16 in the machine 22, however, the filaments 16 are drawn through the curing or fusing oven 18 through which they are threaded by means of a continuous threading belt 19 linearly movable through the oven 18 by reason of its support on a pair of rollers 21 mounted at the inlet and outlet ends of the oven. The belt 19 has a series of spaced cross slats secured thereto which are used in a sense as a belt. This belt performs the function of threading the belt whenever a new filament 16 is to be started. When the apparatus is originally placed in operation all of the filaments 16 are secured to one of the slats 20 and are fed simultaneously through the oven 18, tension created by the belt being relied upon to draw the glass fiber strands 10 off their spools 11 and through the coating apparatus 15. The threading belt can be operated either manually or by an associated drive motor (not shown).

Each of the individual glass fiber strands 10 is individually combined with a suitable quantity of resinous material to form a single filament 16 according to the invention. The coating apparatus 15 comprises a table frame supporting a trough 52 which has inclined ends and an inclined bottom to cause fluid material contained therein to be directed to the inlet of a pump 50 for the coating material. The coating material is pumped by the pump 50 to a filter 51 prior to being fed to the glass fiber strands 10. A thermosetting control mechanism 53 associated with conventional heating elements (not shown) is arranged to maintain the fluid within the trough at a desired temperature for application to the strands.

Referring now more particularly to Figures 2 to 5, the coating material is introduced to the strands 10 by pouring it .on each'strand as it moves horizontally through a die or wiper 33. A series of wipers 33 one for each of the strands to be coated is mounted on a cross support bar36. The coating material is poured onto each strand I in theform of a stream 31 which is pumped from an overhanging gooseneck-type tube structure 30 extending from a main supply manifold 40 by way of a vertical connecting tube 41 having an associated flow control valve 42. The strands "10 are each guided in their, path under a stream 31 through a wiping die 33 and then through the oven by alignment at support points on its respective guide eye 14 at the inlet end of the coating machine and an idler guide wheel 25 at the inlet side of the winding machine. Before passage through the wiper 33, however, the flow of material on each individual strand 10 is wiped on its underside by passage over the horizontal upper surface 32 of a right-angle member 35 extending. transversely across the path of the strands 10 just before the inlet side of the dies 33.

Each stream 31 of coating material applied to a strand 10 is adjusted at its respective supply valve 42 so that just a sufficient amount of coating fluid is applied to the strand that no excesses drip from the strand prior to its passage over the table surface 32. The coating fluid thus rides the upper surface of the strand as it gradually flows over the sides and about the strand. But before the material can drip, it is passed over the table surface 32. The strand movement through the die is at such a rate that the distance between the point of application of the coating fluid from the stream 31 to the strand 10 is of appreciable length prior to passage over the table surface 32. Without the presence of the table surface 32, the coating fluid in most instances would drip at a point just behind the leading edge or the edge of approach of the strand to the'surface if the surface were not there.- In view .of the fact that the table surface is present, however, it acts as a wiper for the underside of the strand, and any air pockets that might be developed bya gradual flow of the coating fluid about the strand are wiped away, and an intimate contact of the coating fluid with at least the surface fibers of'the strand are established prior to its passage through the die 33.

The dies 33 in each instance have a conical or flared inlet opening gradually reducing in size to a small aperture at the backside of the die of dimension generally corresponding to that desired of the composite monofila ment produced. By reason of the speed of the strand through this inwardly flaring inlet, and the fact that excesses of coating fluid are carried therein with the strand, the fluid is drawn into, or in a sense, pumped into the Wide opening of the die as shown in Figure 5 and is caused to exert radially inward pressure on the strand. The pressure is applied from all sides of the strand thereby causing the fluid, in a sense, to be pumped to the spaces between filaments of the strand. The aperture at the backside of the die is of such dimension that it acts as a wiper and minimizes the amount of fluid that is carried through, thereby causing the aperture boundaries to wipe the coating on the strand to the size desired. By minimizing the amount of excess carried through the aperture, the surface of the coating material is also polished.

Wiping of the coating material at the underside of the strand, prior to passage through the die, beside establishing a more intimate relation of the coating material with the strand, distributes the coating fluid across the table surface causing it toact in a sense as a weir on which an accumulation of the coating fluid is present flowing to the trailing edgeof the table surface for overflow into the trough of the coating unit 15. The table surface 32 also acts as a guide for strands passing through their respective dies. The overflow from the table surface is deposited in the trough and mixed with the accumulation therein which is maintained at the desired temperature by the heating elements controlled by the thermostatic control unit 53. The table frame 55 is-connected to'a supply source of coating fluid (not shown) and is arranged to replace the material'removed from the trough 52 and applied to the strands. This arrangement is made automatic by providing level controls associated with the trough to maintain the level therein at a constant height.

By way of illustration of the general proportions and operating characteristics of the coating apparatus of Figures 2 to 5, the invention lends itself to ready application of coating fluid to a strand moving at a velocity in the order of 450 feet per minute. Plastisol at a temperasaris-s3" time at about 85 F. would under such circumstances be introduced to the strand at a point approximately 3 inches in front of the angle member 35. Also under these conditioris, the outlet of the gooseneck tube is located approximately 1 /2 inches above the strand which allows the stream to neck down to a small diameter, and by proper adjustment of flow, just the right stream size can be established that will effect carriage of all the fluid by the strand for the 3 inch distance to the surface 32 without dripping.

Still further by way of example, a strand or yarn of 204 filaments each in the order of .00035" diameter, when supplied with a plastisol and then passed through a die having an aperture of .015" in diameter, provides a filamentary material having 60% plastisol and 40% glass by volume.

The fusing of the coating material within the oven is accomplished at a temperature of approximately 450 F. and the length of the oven required for fusing at such temperature when the strand is moving at the rate of 450 feet per minute is in the order of 14 feet.

The method of application of material to strands is especially adapted to application of coating material having a high solids content such as plastisols which in general comprise vinyl copolymer resin dispersions in plasticizers. Coating materials comprising mixtures such as plastisols including particles of material-like colored aluminum flakes added to produce desired colors are also efficiently applied by this method. Other materials applied by this method are polyvinyl chloride, organosol compounds, neoprene cement, hot melts such as asphalt, waxes such as chlorinated wax, and practically any coating material which will solidify either by cooling to ambient temperature or by subsequent treatment such as by cure or fusion. Many coating materials such as asphalt, chlorinated waxes or other thermoplastic type compounds would not require ovens following application to a strand since theywill solidify sufficiently at room temperatures for winding. Additionally, plastisol compounds including hammermilled glass flakes of extremely minute magnitude can be applied by this method. The plurality of glass platelets of this character being applied with plastisol, or in a soft vinyl coating, which is subsequently cured provide highly reflective surfaces of decorative character for coated strands. After being coated with material such as resin, the filamentary form can be metal plated by vapor deposition or vacuum plating of metal thereover. Metal such as aluminum or copper can be plated on the resin in this manner to improve its Wearability as well as to provide a glittering product with considerable eye appeal.

Although reference is made in the present description to a strand or yarn as the reinforcing or strength imparting means for the filamentary material produced, the term is not intended to be limited to a particular strandlike form since the coating process is usable in coating monofilarnentary forms, as well as cordage and roving, beside twisted and plied yarns and untwisted groupings of continuous and staple fibers.

A high solids content in coating'fluid has heretofore frequently presented considerable difliculty due to settling out when the strand is applied by a dip method such as by passage through a trough. The settling out of solids caused difliculty in eflforts to provide uniformity of dis tribution of the solids along the length of the strand. By the present method, however, all the solids of the coating fluid are applied to the strand without opportunity for them to settle out. Furthermore, by passage of the strand over the guide or table surface 32 prior to any drippage of the coating fluid therefrom, even greater assurance of distribution of the solids on the strand for uniformity is assured.

The table surface 32 can also be used to provide a zone within which supplemental amounts of coating fluid can be introduced if desired. Such additional coating fluid might include solids in suspension which can be applied at the surface of the strand on passage through the die. Further in this respect, additional coating material such as glass platelets can be applied to the strand after passage through the die and prior to introduction two-stage coating process, especially in view of its being relatively compact compared to other high-speed coating methods. In this respect, a strand which is. already coated may be recoated according to the present coating method for finishing purposes in View of the method having the ability to provide a polished surface. The polished effect is produced, as mentioned previously, by reason of the fact that the filaments in the strand are not subjected to lateral forces on passage through the die, thereby minimizing tendency toward wiping of the coating fluid down to the bare fibers. In other words, a full coating of the strand of filaments is assured and the natural generally circular configuration of the strand is maintained on passage through the die. In view of these facts, the shadow effects produced by incongruities .in the surface, and the contrast between the color of the fiber and the coating material thereover, which would otherwise show upquite clearly to the detriment of the product, is not present.

In view of the foregoing, it will be understood that while we have shown a particular form of our invention, we do not wish to be limited thereto since many modifications may be made Within the concepts of the invention, and we therefore contemplate by the appended claims to cover all such modifications as fall within the true spirit and scope of our invention.

We claim:

l. The method of coating a fibrous glass strand comprising moving the strand lineally in a generally horizontal path, pouring a single stream of coating material on said strand at a flow rate such that substantially all the coating material of the stream is conveyed over the path of said strand as it flows in enveloping relationship about said strand, wiping the coating material on the underside of said strand to distribute the material flowed to the underside thereof, passing said strand and coating material through a sizing aperture to wipe the excess of coating from said strand, and then treating said coating material to effect a set thereof as a coating on said strand.

2. The method of applying fluid coating material on a fibrous glass strand comprising moving the strand in a generally horizontal path, flowing a single stream of coating material from an orifice associated with a source of the coatingmaterial, spacing said orifice above said strand 2. distance such that the material flowing therefrom necks down above said strand to a smaller diameter than that at its point of emission from said orifice, deflecting substantially all of the material of said stream with said strand and conveying the deflected material in the path of the strand as the material flows in enveloping relationship about the strand, wiping the coating material which flows to the underside of said strand, and then passing said strand and coating material through a sizing aperture to wipe the excess therefrom to thereby leave the strand coated to the thickness desired.

3. The method of applying fluid coating material on a fibrous glass strand comprising flowing a stream of coating material from an orifice associated with a source of the coating material, moving said strand lineally in a path passing transversely under said orifice and through said stream, deflecting substantially all of the material of said stream with said strand and conveying the deof heat-settable coating material on said strand at a flow rate such that substantially all of the coating material in the stream is conveyed over the path of said strand as it flows in enveloping relationshipabout, said strand,

passing said strand and coating material over a surface in close proximity thereto to effect a wiping of the portion of the coating material which flows to the underside of said strand, forcibly impregnating the interstices be tween filaments of said strand with said coating material, passing said strand and coating material through an aperture to wipe the excess of coating from said strand to the thickness desired and passing said wiped coated strand through a heating zone to set the coating material thereon.

5. The method of applying coating material in fluid form on a fibrous glass strand comprising flowing a stream of coating material from an orifice disposed above said strand and associated with a source of the material, moving the strand to be coated lineally in a path transversely through said stream at such velocity that the entire stream is deflected with said strand, conveying the deflected material with the strand as it flows in enveloping relationship about the strand, Wiping the underside of said strand to distribute the material flowed to the underside thereof, and then wiping said strand on all sides to remove the excess of said coating material to thereby leave the strand coated with the material to the thickness desired.

6. The method of producing a filamentary material comprising flowing a stream of heat-settable coating material from an orifice associated with a source of the material, moving a strand of continuous glass filaments lineally in a path transversely through said stream, spacing said orifice above'said strand a distance such that the material flowing therefrom necks down above said strand to a smaller diameter than that at its point of emission from said orifice, moving said strand in its path through said stream at such velocity that the entire stream is deflected with said strand, conveying the deflected material with the strand as it flows in enveloping relationship about the strand, wiping the underside of said strand to distribute the material flowed thereto, forcibly impregnating the interstices between filaments of said strand with said coating material, wiping said strand on all sides to remove the excess of said coating material to the thickness desired of said filamentary material, and passing said wiped filamentary material through a heating zone to. set the coating material incorporated therein.

7. The method of producing filamentary material according to claim 6 wherein the wiping on all sides of the strand to remove the excess of coating material is effected by an apertured die through which the strand passes, the die being positioned for straight line passage of the strand therethrough without modification of the path from that which it would be without presence .of the die.

References Cited in the file of this patent UNITED STATES PATENTS 1,198,350 Heany Sept. 12, 1916 1,957,942 Convers May 8, 1934 2,034,546 Weeks et al. Mar. 17, 1936 2,392,805 Biefeld Jan. 15, 1946 2,684,318 Meek July 20,1954

FOREIGN PATENTS 309,866 Great Britain Jan. 30, 1930

Claims (1)

1. THE METHOD OF COATING A FIBROUS GLASS STRAND COMPRISING MOVING THE STRAND LINEALLY IN A GENERALLY HORI ZONTAL PATH, POURING A SINGLE STREAM OF COATING MATERIAL ON SAIS STRAND AT A FLOW RATE SUCH THAT SUBSTANTIALLY ALL COATING MATERIAL OF THE STREAM IS CONVEYED OVER THE PATH OF SAID STRAND AS IT FLOWS IN ENVELOPING RELATIONSHIP ABOUT SAID STRAND, WIPING THE COATING MATERIAL ON THE UNDERSIDE OF SAID STRAND TO SISTRIBUTE THE MATERIAL FLOWED TO THE UNDERSIDE THEREOF, PASSING DAID STRAND AND COATING MATERIAL THDROUGH A SIZING APERTURE TO WIPE THE EXCESS OF COATING FROM SAID STRAND, AND THEN TREATING SAID COATING MATERIAL TO EFFECT A SET THEREOF AS A COATING ON SAID STRAND.

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