METHOD AND APPARATUS FOR APPLYING POWDERED MATERIALS TO FILAMENTS

Abstract: Process and device for the treatment of threads, slivers and the like consisting of various filaments and optionally processed in a tissue or knitwear comprising suspending a treating agent in one or more gas or liquid streams, which are thereupon directed to the material to be treated under controllable pressure.

Description: ■r -1 - Method and apparatus for applying powdered materials to filaments The invention relates to a process and a device for treating threads, slivers or the like consisting of various filaments and optionally processed in a tissue or knitwear with a treating fgent, a separation between the filaments being effected in order to have t.he agent better penetrate into the structure of fi laments. Simi lar processed and devices are generally known, in 10 particular for the production of composed materials consisting of thermoplastic or thermosetti ng substances, wherein filaments function as reinforcing material. For instance in Dutch patent application 70 01623 a process is described, wherein the threads of slivers 15 consisting of a great number of filaments are separated before a synthetic resin in powder form is applied thereon, whereupon this resin is molten in result of which a coherent product is obtained. The spreading of the filaments in the slivers is for instance 20 effected according to the Dutch patent application by giving to the filaments an electrostatic charge with the same sign. According to another embodiment the slivers are passed through a venturi, which in the same direction is passed by a fluid at a high velocity. The spreading of the filaments occurs then under the influence of the relaxation of the fluid on leaving the venturi . The invention provides for a process as mentioned in the preamble, which is characterized in that the treating atent is suspended in one or more gas or liquid streams which are then directed to the material to be treated under controllable pressure. It has turned out that in this way a very efficient spreading of the filaments is effected, as a result of which impregnating material suspended in the streams of fluid penetrates well between the filaments and impregnate same very homogeneously. This results in. the final product, for instance a sheet of ' plastic material reinforced by filaments, being of a very homogeneous composition. The process according to the invention is applicable no matter what the nature of the filaments or the nature of the impregnat ng agent is. For instance, powdery ceramic products and metal products are considered as impregnating materials in addition to thermoplastic or thermosett i ng materials. The process according to the invention is also feasible for the application of layers of impregnating material of various thicknesses on var ous sides of the material to be impregnated. For instance a tissue or knitwear which is applied internally or externally to a light¬ weight core can be impregnated by application of the invention. As treating agent a grinding material can also be used, which makes the material treated with it rough, in result of which it is made better suitable for the adherence to it of a sizing and the like. It is preferred to direct the gas streams wherein the treating material is suspended with application of the venturi principle to the material to be treated. The treating material can be suspended in a gas stream in various ways, for instance by atomizing it in the gas stream as a melt or liquid. It is also possible to dose a powdery treating material directly into a gas or liquid stream from a container. It 'is also possible to suspend the treat ng material in a fLuidized bed in a gas and to withdraw the gas streams to " be directed to the material to be treated from the fluidized bed by suction power. Per se the application of a fluidized bed for the impregnation of bundles of fi laments is known, for instance from Dutch patent specificat on 151 928. In this known method, however, the material to be impregnated is passed through the fluidized bed of impregnating material. If, however, in the process according to the invention a fluidized bed is applied, the actual impregnation occurs outside this bed. The invention also relates to a device for carrying out the invented process with a space wherein via a perforated bottom a gas can be fed and a supply-pipe for powdery treating agent, said device being characterized in that the said space is provided with one or more suction pipings, which on the discharge side debouch into means which are reciprocable movable transversely to the path which the material to be treated covers during operation of the device. If the gas is directed to the material to be treated from various sides, care can be taken that the gas streams do not fully collide with each other. It is also possible, applying the invention, to apply various impregnating materials, either over each other, or to various faces, in several spaces separated from each other, in order to preve/it aη undesirable mixing of the various impregnating materials. The invention will be i llustrated hereinunder by way of example with the aid of the follo ing description as well as the enclosed figures. Fig. 1 is a side view in cross-section of a schematically drawn installation for carrying out the process . •Fig. 2 is a top view of the device according to the i nventi on . Fig. 3 is a side view of the very same device. Fig. 4 is a cross-section A.A of the very same device Fig. 5 is an enlarged representation of an essential part of the device according to figures 2, 3 and 4. Fig. 6 gives a number of variants a-e incl. of the applicat on of the invention. As represented in fig. 1 widths of continuous fi lament beams 1 are formed by unwinding them from the horizontal coils 2 under automatically maintained controllable tension. Via the guiding 3 the bundles come into the preheating oven 4. The oven is heated with the automatically controllable heat source 5. Then the dried and preheated fi lament beams are passed through a thermally isolated receptacle 7, via the guiding 6, where impregnation takes place !vide fig..2-6 incl.) . There¬ upon the bundles are passed via the melting furnace 8, wherein one or more heating bodies, are applied controlled by t ermocouples. Same .are automatically controlled by the : means 9 at a predetermined heating intensity. There- upon the filament bundles are. formed into bands and passed through a cooling means 11 via cooled forming rollers 10 and wound on the collecting coil 14 via delivering rollers 12 and the guiding 13. This coil is driven by the electromotor 15. After the delivering rollers 12 the band of filaments can also further be processed for instance by cutting it longitudinally and/or transversely. The installation for carrying out the process can, if desired, be carried out wholly or partly vertically. In the device according to figures 2-5 incl. the bundles of filaments in the thermally isolated impregnation receptacle 7 are distributed over the rollers 16, which are positioned outside the feeding axes. Optionally the axes of the rollers 16 are mounted pivotally about the shaft 17 pair-wise. This makes it possible that the bundles can be positioned in the centerline when they are pulled into the device. Spreading of the bundles over more than one layer of rollers, in this case two, facilities a better distribution of the filaments. After having passed the rollers the filaments are impregnated. The powdery impregnating material which is fed from the dosing device 18, is fluidized in the bed 20 in gas 21 fed through the perforated bottom 19. Preferably this gas is preheated. In the spaces 22 under the influence of pumping action, gas streams wjierein the impregnating material is suspended are sucked under controllable pressure from the fluidized bed to the impregnating heads 23, from which it is directed to the continuously moving bundles of fi laments In order to effect an optimal impregnation the impregnating heads 23 are optionaLly adjustable with respect to distance and/or angle turning in regard of the material to be impregnated. The various parts which are applied in the impregnating receptacle 7 can simply be displaced and/or replaced. For instance other types or rollers, and/or other impregnating heads can be used for the impregnation of various types of material. The gas streams with therein the finely divided impregnating material are preferably directed to the filaments .to be impregnated from two or more impregnating heads. This results in a very homogeneous distribution of the impregnating material over the ndividual filaments. The impregnating method described makes it possible to operate with a considerably lower filament tension then required in a mechanical impreg¬ nating system, in which the impregnating material is pressed between the filaments by means of pressure rollers. The lower f lament tension results in the substantial elimination of filament rupture which often occurs in the mechanical impregnation of for instance carbon filaments. This combined with the more intensive impregnation also makes a greater impregnation rate possible. In fig. 5 it is indicated that the suction of the gas " wherein the impregna i ng ' ateri al is suspended occurs through the conduit 26 with application of the venturi principle. Via the conduits 25 gas is fed under a controllable pressure. It is preferred to suck the gas fed by a pump through the conduit 25 from the space 7. In result a circulation pump system of the gas is obtained and heat losses are prevented. If no use is made of a fluidized bed it is advantageous to connect the dosing device 18 directly to the i pregnating heads or their supply mains. When using impregnating liquids it is preferred to inject the liquid either directly into the impregnating head ( s ) or to suck it directly from the dosing device 18 In fig. 6 a plurality of schemes of embodiments of more-sided and/or mobile impregnating heads are represented, which are suitable for the continuous mpregnation of bundles of filaments optionally processed in a tissue or knitwear. These bundles are optionally applied to cores. These may have the following shapes: a . rectaπgu Lar, b. cylindrical, c. honeycomb-shaped. For the internal impregnation of hollow structures fully closed along their circumference, which are provided ith f lament materials, the- process must be discontinuous. Then impregnating heads can be applied in the hollow spaces. Then the i pregnating heads and/or- the material' to be impregnated can be moved in such a way that the desired impregnation is attained. This is further illustrated with the aid of figures 6 e and d . Fig. 6 d represents an aeroplane nose 27, w ch internally -and externally is provided with filament material that has to be impregnated. For the internal impregnation use is made of the impregnating head 28 and for the external impregnation of the impregnating head 29. By rotating the nose and reciprocate the impregnating heads 28 and 29 over guidings 30 and 31 the desired impregnation is obtained. In fig. 6e 32 represents .part of a d sh antenna internally and externally is provided with fi lament material that has to be impregnated. This occurs by eans of the i pregnating heads 33 and 34, which are reciprocated radially via guidings 35.and 36. If desired, the motions described can be computer controlled, which makes possible an optimal impregnation of more complex types of material. If bundles of filaments processed into tissues or knitwears are applied to cores, the impregnated material is heated in an autoclave under a predetermined desired pressure. Optionally, heat emitters can be built, in in the autoclave. According to the afore-described way impregnated filament bands optionally woven into a certain shape can be treated to aeroplane noses, radar domes and other structures. It is also possible to apply a melting furnace consisting for instance of two mould halves for heating * . In order to facilitate weaving, knitting and/or twisting with impregnated f lament bands can be separated wholly or partly into narrower bands. These narrow bands are then provided with an additional thin impregnating layer with application of the process according to the invention. This layer consisting of a specially selected impregnating material sees to it that the impregnating material already present between the filament remains in place during weaving and/or knitting and besides prevents the adsorption of moisture In order to effect this the band may optionally be subjected to for instance a temperature treatment on the surface. Particularly in case of impregnating materials of high rigidity the weaving and/or knitting w ' ith narrow bands, which have not been passed through a melting furnace, is possible without a considerable adaptation of the installations in question and loss of velocity. Then the tissue, knitwear and/or twisted material can be passed through a melting furnace in order to be processed further optionally via cooled form ro I lers . As treating agents may for instance be used: Aceta I resi ns Acrylic resins Acrylonitri le-butadiene-styrene resins Aluminium AIkyd resins Aluminia Aryl resins Bismaleimide resins Cobalt Copper Ekonol Epoxy resins Fluorcarbon resins Fluorcopo lymers Lead Melamine resins Nic el Phenol resins Polyacetal resins Po Lyacrylate Polyamide (nylon) Polybutadiene Polybutylenterephthalate Polycarbonate Aromatic polyesters Thermoplastic polyesters Polyetheretherketones Polyetheri ides Po lyethersuIfones Po lya Ikenes Polyethyleneterephthalates Po lyi mi des Po lyoxyme hylen resins Modified po lyphenyIene oxides Polyphenylene sulfides Po lyphenyI ene sulfides Po lypheny Lenoxides Polyphen lsulfones Po lystyrene Polysulfone Polytetrafluorethylene Po lyurethane Poly inylchloride Polyvinylidene fluoride Modif ed polypropylene oxide Silica S l con carbide Sili con nitride Si I i cone Styrene acry Ioni tri le copolymers Styrenic copolymers Ti tani urn Tungsten Urea Vinyl ester Rubbers and addi ti ves li e: Anti static agents Blowing agents Colorants Concrete Coupling agents Fi I lers Flame retardants Foam materials Heat stabi lizers Hollow fillers Lubri cants Minerals Plasticizers Processing aids S i L i cones Stabilizers , • Supera I loys Ultraviolet absorbers Water soluble plastics W iskers. The material to be treated may for instance consist of: Aluminium Aluminium oxides Arami de Asbestos Boron Carbon Cobalt Copper lass High silica and quarz Lithium aluminium silicate Magnesi urn Nickel Po lya I kene Si lica Si licon Si licon carbi e Si licon nitride Steel Titanium Tungsten Zinc Z i rconi a Zi rconium.

Claims: -14- CLAIMS 1. A process for the treatment of threads, slivers and the like consisting of various filaments and optionally processed in a tissue or knitwear, with a treating agent, a separation being effected between the filaments, characterized in that the treating agent is suspended in one or more gas or liquid streams, which are then directed to the πaterial to be treated under a controllable pressure. 2. A process according to claim 1, characterized- in that, the gas streams are directed to the material to be treated ith application of the venturi principle. 3. A process according to claim 1 or 2, characterized in that the gas streams wherein the treating material is suspended is directed to the material to be treated from various sides. 4. A process according to claim 3, characterized in that the gas streams which are directed to the material to be treated from various sides, do not fully collide with each other. 5. A process according to any of the preceding claims, characterized in that the means from which the gas streams flow to the material to be treated are moved over this material in a reciprocating manner. 6. A process according to any of the preceding claims, characterized in that powdery treating agent is suspended in a fluidized bed in a gas and that the gas streams to be directed to the material to be treated are withdrawn from the fluidized bed by suction power. 7. A process according to any of the claims 1-5, characterized in that the treating atent is directly fed to the gas streams directed to the material to be treated in dosed amounts. 8. A process according to any of the claims 1-6, characteri zed ,i n that the treating atent is suspended by atomization in the gas streams to be directed to the material to be treated as a melt or liquid. 9. A process according to any of the preceding claims, characterized in that the treating agent is an impregnating agent. 10. A process according to any of the claims 1-8, characterized in that the treating atent is a grinding agent for making rough the material treated with it in order to make this better suitable for adherence thereon of a sizing and the like. 11. A device for carrying out the process according to claim 1 with a space to which via a perforated bottom a gas can be fed and a supply for powdery treating agent, characterized in that the said space is provided with one or more suction pipings, which on the discharge sides debouch into one or more spaces, wherein the gas streams are directed to the material to be t reated . 12. A device according to claim 11, characterized in that the suction pipings debouch into means which are reciprocable over the path which the material to be treated covers during operation of the device.

Inventors: DE JAGER GUI G, DE JAGER, GUI, G.
Applicants: FLEXLINE SERVICES LTD, FLEXLINE SERVICES LTD.
Application year: 1986
Main classification: D06B1
IPC codes: B05B13, B29B15, D06B1, D06C11, D06M23