Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06B—TREATING TEXTILE MATERIALS USING LIQUIDS, GASES OR VAPOURS
  • D06B3/00—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating
  • D06B3/04—Passing of textile materials through liquids, gases or vapours to effect treatment, e.g. washing, dyeing, bleaching, sizing, impregnating of yarns, threads or filaments
• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/18—Separating or spreading

Definitions

• the present invention relates to a method of manufacturing a fibrous product impregnated with a thermoplastic material of the type according to which a bundle of continuous fibers is made to travel between two aligned passage points on a determined path, the fibers are separated from the bundle of so as to open the latter transversely to its path, a thermoplastic material in molten, liquid or pulverulent form is introduced between the separated fibers, the fibers of the impregnated bundle are collected and the thermoplastic material is at least partially adhered to said fibers of the bundle.
• a bundle of continuous fibers is passed through at least one deflection roller to flatten the section of said bundle and to introduce the flattened fibers into a fluidized bed containing thermoplastic powder in suspension and in which said fibers are loaded, along an essentially horizontal path, with the particles of thermoplastic material before leaving the fluidized bed, so that said thermoplastic particles can then be mechanically forced to penetrate between the parallel fibers of the bundle by virtue of the passage of these between rollers provided at the outlet of the fluidized bed, the bundle of fibers loaded with thermoplastic particles then being passed through an oven where the thermoplastic material is heated to the melting temperature, all the fibers provided with the molten thermoplastic material then being calendared after removal from the oven for constit uer the final composite product.
• This technique has the drawback of mechanically stressing the fibers by traction, especially during the phase when the particles of thermoplastic material are penetrated into the interstices between the juxtaposed continuous fibers, this stressing of the fibers occurring at a time when they are fragile, since they are not yet protected by the impregnation product (thermoplastic material) which, after melting, fixes together said continuous fibers.
• this known method also has the disadvantage of not allowing a homogeneous distribution of the powder in thermoplastic material and the dosage of the quantity of thermoplastic material necessary to constitute the impregnation matrix.
• the quantity of powder which mechanically penetrates into the intervals remaining between the fibers due to the pressure exerted on said powder by the rollers located either in the downstream part of the fluidized bed, or outside said bed and downstream thereof leads to a heterogeneous and difficult to control distribution.
• the particles of thermoplastic material are sent in the direction of the flattened fiber bundle from above and from below said bundle, so that the upper face of the flattened fiber bundle always contains a greater quantity of thermoplastic material than that which adheres to the underside of said bundle.
• a random quantity of thermoplastic particles will fall from said bundle with each change of orientation of the latter.
• gaseous jets carrying particles of thermoplastic material are used, not only for depositing these particles on the fibers of the bundle, but also for separating said fibers in order to facilitate the penetration of said particles in the intervals between said fibers.
• the two gas jets charged with particles of thermoplastic material are reflected at least partially on the flat surfaces determined by the flattened fiber bundle and thus entrain a more or less significant quantity of suspended particles outside the fiber bundle. in said gas jets.
• the placing of the impregnation products, that is to say particles of thermoplastic material, in a gaseous carrier fluid and the use of this same gaseous fluid under pressure to separate the continuous fibers from the bundle of fibers previously laid flat by the passage of said bundle between rollers does not make it possible to separately adjust the parameters of separation of the fibers and those of the impregnation of the bundle of fibers.
• the pressure of the gaseous fluid, to separate the fibers from the bundle does not necessarily correspond to the pressure favoring a good impregnation of the bundle of fibers with the particles of thermoplastic material, a more or less significant quantity of these particles will be reflected or fall back randomly, which also leads to heterogeneity in the final product.
• the present invention aims to eliminate or at least mitigate the drawbacks of known methods and which ensures good separation of the continuous fibers from the bundle, as well as good impregnation of the latter with thermoplastic material.
• this object is achieved by the fact that the bundle of continuous fibers is made to pass over a substantially vertical path under a low tension close to that due to the weight of the section of suspended beam, applied to fibers constituting the substantially vertical bundle section, at least one transverse force using at least one gas jet to cause the opening of the bundle and the separation of the fibers by deflection thereof, and one puts , downstream of the deflection zone, the thermoplastic material under low pressure in contact with the open bundle of fibers, so as to place the thermoplastic material between and around the separated fibers.
• the degree of opening of the fiber bundle and the quantity of thermoplastic material used to impregnate the bundle can be adjusted independently and optimally.
• the present invention also relates to an installation for manufacturing a fibrous product impregnated with a thermoplastic material, of the type comprising at least one reel for storing a bundle of continuous fibers, means for continuously unrolling at least the bundle of fibers. , means for guiding the continuous fibers on a treatment path, means for separating the fibers from the fiber bundle, means for applying thermoplastic material between and around the fibers spaced from the bundle, heating means for melting at the at least partially the thermoplastic material to be deposited between and around the fibers spaced from the bundle or already deposited between and around them as well as means of subsequent treatment making it possible to arrive at the finished fibrous product impregnated with the thermoplastic material and having a profile and a determined structure.
• the fiber bundle passes over a certain number of bars or rollers determining a sinusoidal path while being subjected to a controlled tension. Therefore, the spacing of the fibers of a bundle of continuous fibers is, in this case, ensured by another means, namely the use of at least two gaseous jets which transport particles of thermoplastic material at the same time towards the upper face and the lower face of the fibers more or less spread out in the form of sheets. It has already been mentioned previously that this way of proceeding does not make it possible to obtain a final fibrous product in which the thermoplastic impregnation matrix is distributed in a homogeneous manner.
• Another object of the present invention therefore consists in proposing an installation of the type initially mentioned which makes it possible to avoid or at least attenuate the drawbacks of the prior art.
• the means for guiding the continuous fibers on a treatment path, at least in the zone of separation of the fibers, the zone of impregnation of the bundle of fibers with thermoplastic material. and in the heating zone, are arranged one above the other, so as to allow the suspension of the fiber bundle and to determine a substantially vertical path along which the fiber bundle or the spaced apart fibers travel under a low tension close to that due to the own weight of the suspended bundle section, that the means for spreading the fibers are arranged below the means for applying thermoplastic material between and around the fibers separated from the bundle and comprise at least one nozzle ramp arranged very close to or in the plane of the vertical path and whose gas jets directed transversely on the fibers flex and temporarily deflect said fibers from their vertical path so as to cause them to assume a similar shape to a half-sinusoid, and that the means for applying thermoplastic material are provided above the spacing zone by deflection of the fibers and around the open bundle.
• FIG. 1 is a diagram showing a manufacturing installation in accordance with the invention
• FIG. 2 schematically shows an elevation view of a section through another embodiment of the means for separating the fibers from the fiber bundle and means for applying thermoplastic material between and around the fibers of the open bundle
• FIG. 3 schematically shows an elevation view of a section through yet another embodiment of the above-mentioned means for spacing the fibers and applying thermoplastic material
• FIG. 4 schematically shows a view of an embodiment similar to that of FIG. 1, but suitable for the simultaneous treatment of at least two bundles of fibers,
• FIG. 5 shows schematically in perspective a distributor of gas jets used to separate the fibers from a bundle of fibers
• FIG. 6 shows a detail of the means for applying thermoplastic material in the form of a fine powder between and around the fibers of an open bundle of fibers
• FIG. 7 schematically shows a detail of the means for applying molten thermoplastic material or in liquid solution between and around the fibers of a bundle of fibers
• FIG. 8 shows a succession of rollers with a calibrated profile making it possible to bring the fibers closer to an impregnated bundle and to expel occluded air and express excess thermoplastic material
• FIG. 9 shows two pairs of rollers working successively each in one of two planes perpendicular to each other and to the path of the bundle of impregnated fibers
• FIG. 10a is a plan view of a compacting assembly using several successive dies to bring together several fiber bundles together and the continuous fibers of each of the impregnated bundles,
• FIG. 10b shows in elevation the upstream face of a first pultrusion die according to FIG. 10a
• FIG. 10c shows in elevation the upstream face of a second pultrusion die according to FIG. 10a
• FIG. 11a shows a " plan view of a section of a first ply of parallel fibers impregnated with thermoplastic material
• FIG. 11b shows a plan view of the section according to FIG. 11a on which a section of ply is superposed parallel fibers impregnated with a thermoplastic material and adhering to the first ply according to FIG. 11a,
• FIG. 12 schematically shows an axial section through a die serving to form a hollow cylinder from a sheet or strip of parallel fibers impregnated with thermoplastic material
• FIG. 13 schematically shows a cylinder section consisting of continuous fibers parallel to each other and to the axis of said cylinder and embedded in a matrix of material thermoplastic, this cylinder receiving a ribbon also consisting of a plurality of continuous fibers embedded in a matrix of thermoplastic material,
• FIG. 14 schematically shows a succession of operations for processing a bundle of fibers
• FIG. 15 shows a table of operations of an example of processing a bundle of fibers until a final product is obtained.
• the installation for manufacturing a fibrous product impregnated with a thermoplastic material comprises, on the path of at least one bundle of continuous fibers 1, a storage reel 2 on which is wound in turns said bundle 1 and whose horizontal axis 3 is carried by bearings 4, 5 and rotated by a motor 6 at adjustable speed, so that the bundle 1 can be unwound from said coil 2 at constant speed independently of the diameter of the turns and without significant traction effort.
• a motor 6 at adjustable speed
• a first point of passage 7 constituted, for example, by a vertical cylindrical sleeve guide through which the bundle of continuous fibers 1 passes, following its substantially vertical path.
• Plumb and above this first crossing point 7, a second crossing point 8 is provided which is also constituted by a vertical guide sleeve of circular oval or rectangular section and the internal diameter or width of which can be if necessary, be larger than that of the first crossing point 7 to which it is vertically aligned.
• the means 9 for spread the fibers of the bundle 1 comprise at least one nozzle 12 disposed downstream and, according to the example of FIG.
• this nozzle 12 makes it possible to blow through its outlet orifice a jet of gas directed transversely on the bundle of fibers 1 after the latter has passed through said first guide sleeve 7.
• the nozzle 12 is orientable around an axis horizontal, so that the axis of the gas jet such as an air jet includes with the generally substantially vertical axis of the fiber bundle section between the two crossing points 7, 8 an acute angle which can vary according to needs between 15 and 65 °, it being understood that, in this particular case, the gas jet is directed from bottom to top, like the movement of the fiber bundle 1.
• the opening of the fiber bundle 1 is obtained while the latter runs on a substantially vertical path and at a low voltage close to that due to the weight of the section of the suspended beam, by applying at least one transverse force on said section of fibers using at least one gas jet.
• the different successive sections are thus bent during the practically tensionless continuous movement of the bundle of fibers 1 and consequently the opening of the bundle 1 and the spacing of the fibers 10 from one another.
• the effect of the opening of the bundle 1, that is to say of the spacing of the fibers 10 can be reinforced or improved by the use of several blowing nozzles 12 distributed around the bundle of fibers 1, for example , on a ring 13 or two half-rings for supplying compressed gas provided downstream, and in the case of FIG.
• the fibers 10 of the bundle form, by bending and moving away from each other, a sort of "cage of 'bird' between the two ertically aligned guide sleeves 7, 8.
• the installation comprises, downstream of the means 9 for separating the fibers 10 from the bundle of fibers 1 and upstream of the second point of passage or vertical guide sleeve 8, the means 11 for applying between and around the fibers 10 of the bundle 1 a thermoplastic material which will subsequently form the matrix of the final fibrous product, matrix in which the fibers 10 will be embedded.
• the present invention does not affect the nature of the fibers and the thermoplastic materials used in its context and that all the suitable fibers and thermoplastic materials can be used, in particular those mentioned in European patent 0 133 825, patent FR-2516441 and patent application WO87 / 00 563, without this being limiting in nature.
• the application means 11 are provided in a zone which is located downstream and in the immediate vicinity of the horizontal plane of maximum deflection 14 of the fibers 10, plane 14 which corresponds to the maximum opening of the bundle 1, this zone extending practically up to the entry of the bundle 1 into the second vertical guide sleeve 8.
• the thermoplastic material which constitutes the material for impregnating the open bundle of fibers can be found in very different states when applied to fibers 10. 11
• thermoplastic material can be in the molten, liquid, pasty state, in solution, in the form of powder or fine particles, in aerosols, or in the form of short fibers, etc.
• the application means 11 comprise, upstream of the second passage point 8 relatively close to the latter and in a place where the spaced apart fibers 10 approach as they advance towards said second passage point 8, channels feed 15 through which the thermoplastic material, for example in the form of fine powder particles 16, is sprayed, under low pressure, towards the fibers 10, so that these particles sprayed out of the channels 15 and then falling through gravity can enter the open bundle, meet or strike ascending fibers there, surround them and temporarily adhere to them.
• air jets under low pressure are used to transport the particles of thermoplastic material 16 to and in the open bundle of fibers 1 and that the low pressure of the transport jets is not suitable for open the bundle of fibers 1 or to expel or remove the particles of thermoplastic material already adhering to said fibers.
• an enclosure 17 which extends for example from the horizontal plane of maximum deflection 14 to the second upper guide sleeve 8 and which at its wall lower comprises a wide passage opening 18 which takes account of the maximum amplitude of the deflection of the fibers 10 relative to the general vertical axis 19 of the path of the fiber bundle 1, the upper wall 20 of this enclosure 17 being provided with the second vertical guide sleeve 8 and supply channels 15 which are situated on either side of said second sleeve 8, are preferably distributed uniformly around said sleeve and open into said enclosure 17 near the periphery of the open bundle of fibers 1 , converging towards the axis 19 of said beam 1.
• thermoplastic material 16 which, with respect to spread fibers running from bottom to top, going against the current with respect to the bundle of fibers 1 under the effect of the force of gravity in the enclosure 17 has numerous occasions to meet and adhere to a fiber or several fibers during from its fall in the enclosure 17. It should also be noted that as the spaced apart fibers 10 move away from the plane of maximum amplitude of the deflection of the fibers 10 by going up towards the second guide sleeve 8, they approach each other by squeezing together the particles of thermoplastic material 16 applied to them.
• thermoplastic material makes it possible to provide the latter in excess inside the bundle 1, which ensures the fibrous product final a matrix in sufficient quantity allowing to perfectly coat all the fibers of said product.
• thermoplastic material 16 To improve the rapid adhesion of the solid particles of thermoplastic material 16 to the spaced apart fibers 10, when they come into contact with them in the application zone, it is advantageous to preheat the bundle of fibers 1. This can be done conveniently and simply by using hot gas jets for opening the fiber bundle 1.
• the temperature of the gas, in particular of the air, forming the gas jet is generally between 100 and 200 ° C., it being understood that the temperature of hot air for opening the fiber bundle will be chosen in such a way that, d on the one hand, it is high enough to eliminate the humidity contained by the bundle, to preheat the fibers and facilitate the fixing of the thermoplastic powder on the fibers and, on the other hand, it is low enough not to destroy the fiber sizing.
• the installation Downstream and above the second point of passage or vertical guide sleeve 8, the installation comprises a tunnel oven 21 with gradually decreasing temperatures from bottom to top, for example from 700 ° C. at the lower inlet and from 400 ° C at upper outlet. Of course, the thermoplastic material passing through this oven 21 does not reach the temperatures of the oven.
• thermoplastic material can be melted either completely, either partially and notably superficially just so as to make it adhere permanently, still in the form of powder or particles, to the fibers of the impregnated bundle in which the fibers 10 are more or less close together after having passed through the second vertical guide sleeve 8
• the individual fibers 10 of the impregnated bundle are already sufficiently reinforced to be able to be passed over a first horizontal deflection roller 22 which is placed above the oven 21, so that the vertical median plane of the storage reel 2 perpendicular to the axis 3 thereof and passing through the vertical axis 19 of the path vertical of the bundle of fibers 1 is tangent to the periphery of said first horizontal deflection roller 22 which moreover serves for the suspension of the whole of the bundle section 1 comprised between it and the storage reel 2.
• the bundle flattens in the form of a sheet or ribbon and then passes over a second horizontal deflection roller 23 located at a relatively small distance from the first roller 22 and at the same level than this, so that between these two deflection rollers 22, 23, the sheet or ribbon of fibers follows a section of horizontal path.
• thermoplastic material When the particles of thermoplastic material are partially adhered to the fibers of the open bundle by partial melting of the latter in the furnace 21, said thermoplastic material is cooled, for example as soon as the fibers with the particles partially melted are on the horizontal path between the two idler rollers 22, 23.
• This cooling is advantageously carried out using at least one cold air jet projected using at least one nozzle 24 obliquely on the open bundle of fibers and preferably against the current by relation to the direction of horizontal scrolling of this-here.
• this nozzle 24 can be used to destroy the bridges that the molten thermoplastic material has established between the different fibers or groups of individual fibers, but this time by passing a jet of hot air through them.
• the bundle of flattened fibers comprising fibers surrounded by thermoplastic material enters and crosses a vertical path descending a heat-insulated enclosure 48 of the installation whose height is substantially equal to that of the oven 21. It is in this heat-insulated enclosure 48 that the distribution of the thermoplastic material around the fibers of the bundle can be perfected under the effect of the force of gravity as long as said thermoplastic material is fluid.
• a third horizontal deflection roller 25 deflects the fiber bundle on a lower horizontal path along which said impregnated bundle can be cooled, for example using a plurality of jets cold vertical air at low pressure leaving a perforated box 26 disposed in particular below the lower horizontal path of the bundle 1, the plurality of air jets in this case preferably being perpendicular to said path.
• the bundle 1 can also receive an opening or separation treatment of the fibers coated with thermoplastic material, this opening treatment consisting in subjecting the impregnated fibers to the action of a transverse force produced by at less a jet of coolant.
• This jet of cooling fluid is generally a jet of compressed air preferably directed obliquely from top to bottom and in the opposite direction to that of the travel of the bundle of fibers.
• This jet of air for cooling and separating the impregnated fibers is produced using a horizontal row of nozzles 27 preferably arranged at above the lower horizontal path of the bundle of fibers and having nozzles directed, for example obliquely towards said bundle and in the direction opposite to that of travel of said bundle of fibers.
• the installation comprises compacting means 28 which will be described later.
• the location of these means 28 in the path of travel of the fiber bundle is not necessarily that indicated in Figure 1; it depends more particularly on the succession of partial treatments that it is desired to subject the bundle of fibers to reach the final product, knowing that the compaction takes place before any cooling so that the thermoplastic material is particularly fluid and malleable. As can be seen in FIG.
• the separation of the fibers 10 from the bundle of fibers 1 by deflection of said fibers can advantageously be carried out using a jet of compressed air directed transversely on the suspended bundle of traveling fibers 1 between the two supports or passage points constituted by the two vertical guide sleeves 7, 8 which define the general vertical axis 19 of the upward vertical path of said bundle of fibers 1.
• a jet of compressed air directed transversely on the suspended bundle of traveling fibers 1 between the two supports or passage points constituted by the two vertical guide sleeves 7, 8 which define the general vertical axis 19 of the upward vertical path of said bundle of fibers 1.
• the installation comprises in an enclosure 29 provided between the two vertical guide sleeves 7, 8 fixed respectively on the lower and upper walls thereof, halfway between said said sleeves 7, 8 a blowing device 30 which consists of a horizontal blowing ramp having at least on the side facing the inside of the enclosure 29 a cylindrical periphery to which the axis 19 of the vertical path of the beam 1 is tangent .
• This horizontal blowing ramp 30 comprises at least one row of horizontal nozzles 31 situated in the horizontal axial plane of the ramp 30, the nozzles being perpendicular to the vertical path of the vertical beam section.
• this first row of nozzles 31 can be supplemented by two rows of additional nozzles 32, 33 which are parallel to the first (31) and arranged on either side and close to the latter.
• the nozzles of the two additional rows 32, 33 are inclined relative to the horizontal axial plane of the blowing ramp 30, for example by an angle between 10 and 35 °, the nozzles of the lower row 32 being directed on the beam of fibers 1 from top to bottom and those of the upper row being directed from bottom to top.
• the blowing device or ramp 30 (see FIG.
• nozzles with a diameter or a width generally less than 0.5 mm may have nozzles with a diameter or a width generally less than 0.5 mm, nozzles whose cross sections have different shapes. These sections can be circular, oval, rectangular and be oblique with respect to a radial plane of the blowing ramp 30.
• the horizontal central row of nozzles 31 can advantageously be replaced by a single nozzle in the form of a narrow slot extending over almost the entire axial length of the ramp 30.
• the nozzles of a row can be offset (in the axial direction of the ramp 30) relative to the nozzles of one of the adjacent rows.
• the blowing manifold 30 is constituted by a tube closed at both ends, adjustable connection to a source of compressed air and comprising at least one row of nozzles or a narrow slot acting as a single nozzle. It should be noted that the air jets from the horizontal or central row of nozzles 31 push the air jets from the neighboring rows of nozzles 32, 33 down and up respectively, which makes separation even easier. fibers of the bundle.
• the weakness of the nozzle openings makes it possible to work under high pressure and low air flow, and to produce flat jets of air in the form of one or more neighboring curtains diverging from the blowing ramp.
• the enclosure 29 has at its upper end the curved side of the open beam, and more precisely above the downstream half of the arcuate path (taken in the direction of travel of the beam), that is to say in the zone of travel with decreasing amplitude relative to the vertical axis 19, at least one supply channel 15 opening out above the open beam near said vertical axis 19 and through which is sprayed under low pressure against said open beam 1, thermoplastic powder 16 from a feed container 34 fixed on the upper wall of the enclosure 29 and provided with an endless feed screw 35 as well as a receiving hopper 36 which is fed through a control valve 37 from a storage tank and if necessary through a recycling conduit 38 connected to the bottom of the enclosure 29.
• the mouth end of the supply channel 15 can be slightly bent towards the 'horizontal (without being horizontal) to avoid, if necessary, that the ascending air stream does not push the powder 16 into the container 34 or prevent the flow of said powder 16.
• a vibrating chute can be used at the lower end of which is associated at least one air blowing pipe with the aid of which a weak horizontal air flow is established which pushes or transports the powder towards the beam fiber open as soon as this powder has left the lower end of the chute.
• a similar arrangement can be taken when using a feed channel 15. As can be seen in FIG.
• the installation comprises, in addition to a first unit for opening the bundle 1 as shown in FIG.
• a second opening unit similar to the first unit, but immediately arranged in below, that is to say upstream thereof and symmetrically speaking, on the opposite side with respect to the axis 19 of the vertical path of travel of the fiber bundle 1.
• the same means are therefore found in this second unit than in the first upper unit, so that to designate the different elements, the same references will be used but accompanied by the letter "a” or "b" depending on whether it is an element of the first or of the second unit.
• the two opening units 39a, 39b are arranged between the two vertical guide supports or sleeves 7, 8 of the fiber bundle 1, the vertical axis 19 of the path of the latter also constituting that of the two vertically aligned sleeves 7, 8.
• the lower sleeve 7 is fixed on the lower wall of the enclosure 29, while the upper sleeve 8 is provided on the upper wall of the enclosure 29 which thus surrounds the two opening units 39a and 39b.
• the blowing ramp 30a of the first unit 39a is located to the left of the arcuate or semi-sinusoidal path (curved to the right) of the fiber bundle 1
• the blowing ramp 30b of the second unit 39b is located to the right of the arcuate or semi-sinusoidal path (curved to the left) of the fiber bundle 1 which at the point of intersection 40 intersects the vertical axis 19 of its general path.
• the horizontal blowing ramps 30a, 30b are superimposed and substantially the same distance from the point of intersection 40 and the zone of impregnation with thermoplastic powder is arranged above , that is to say downstream, from the last preceding zone or downstream zone of opening of the bundle and on the opposite side with respect to the upstream supply booms 30a, 30b responsible for prior opening of the bundle 1.
• a dispersion sheet or grid 41a it is possible to have above the last ramp or downstream blowing ramp 30a, and projecting from to these.
• a single impregnation unit is associated with the two opening units 39a, 39b, this impregnation unit comprising, as in the example in FIG. 2, at least one supply channel 15 opening near the upper sleeve 8 on the curved upper face of the fiber bundle, face turned away from the adjacent blowing ramp 30a disposed between the upper sleeve 8 and the point of intersection 40.
• the impregnation unit also comprises a supply container 34, one end of which is connected to the curved channel 15, a worm screw 35 as well as a receiving hopper 36 supplied through a control valve 37 and recycling conduits 38a, 38b connected to the bottom enclosures 39a, 39b.
• two bundles of fibers la, 1b are each taken simultaneously, each consisting of fibers of a different nature from that of the fibers of the other bundle 1b or la, the two bundles of fibers la, lb so as to scroll them side by side and the said bundles la, lb are treated as if it were a single bundle by subjecting them together to the operation of opening or separating the fibers and then to the operation of impregnating said fibers with material thermoplastic. It has been found that this procedure results in the fairly uniform mixing of fibers of a different nature.
• the installation comprises, according to FIG. 4, at least two storage coils 2a, 2b with horizontal axes 3a, 3b each carried by two end bearings 44a, 45a, or 44b , 45b. If the two coils 2a, 2b are aligned horizontally instead of being juxtaposed, the two neighboring end bearings 45a and 44b can be combined in a single bearing, it being understood that the two axes 3a and 3b remain independent and are driven in rotation by two independent motors 6a, 6b, the rotational speeds of which are individually adjustable as required in order to be able to unwind each of the bundles 1a, 1b without significant tension, so that each of the two bundles of fibers and then the common bundle which will result therefrom pass along the substantially vertical path (see axis 19 of said path) under a low tension close to that due to the weight of the sections or of the suspended beam section (s) loaded (s) with thermoplastic material.
• the installation also comprises, analogously to the arrangement shown in FIG. 1, a vertical cylindrical lower guide sleeve 7 placed above and preferably halfway between the centers of the two coils 2a, 2b and above the lower sleeve 7 and vertically thereof, the second upper guide sleeve 8.
• the lower guide sleeve 7 is surrounded by two annular blowing half-rings or half-ramps 13a, 13b each connected separately to a source of compressed air via a duct 46a, 46b provided with an adjustment valve.
• the nozzle (s) 12a, 12b provided on each of the semi-annular blowing ramps are inclined obliquely upwards, are of variable inclination, and include with the vertical axis 13 of the general path of the fiber bundles la, lb an angle acute preferably between 15 and 65 °.
• the gas jets are directed transversely on the bundles of fibers la, lb from bottom to top while converging towards the axis 19 above the lower guide sleeve 7.
• the area between, on the one hand, the plane of the maximum horizontal amplitude of the deflection of the fibers 10 and, on the other hand, the upper guide sleeve 8 is preferably surrounded by an enclosure 17 provided with a wide lower opening 18, and inside which the open fibers 10 are impregnated, for example by spraying under low pressure and through oblique channels 15 a powder of thermoplastic material 16 which penetrates inside the " bird cage "and is placed between and around the individualized fibers 10 and adheres to them.
• the quantity of powder falling on the bottom wall of the enclosure 17 is recycled to the supply containers 34 through a receiving hopper 36 and a recycling conduit 38 connected to the bottom of said enclosure 17.
• thermoplastic powder 16 between and around the open or separated fibers 10 of the bundle 1 having undergone two successive openings, it is also possible, as shown in FIG. 6, to use two impregnation units 49a, 49b each comprising, as in the example in FIG.
• a supply container 34 the front end of which opens out through at least one feed channel 15 on the open bundle 1 near the upper sleeve 8
• an endless screw 35 rotates and is disposed inside the container 34 to push the powder of thermoplastic material through the channel 15 on the open beam 1, as well as a receiving hopper 36.
• These two impregnation units 49a, 49b are arranged downstream of the blowing ramps 30a, 30b of the two successive opening units 39a, 39b, of on either side of the open beam 1 and in such a way that the supply channels 15 are opposed and the thermoplastic powder 16 is sent against the open beam 1 in two opposite directions. This prevents the powder 16, even sent under low pressure, from passing through the fibers separated from the open bundle 1.
• FIGS. 2 and 3 the other elements of this embodiment, they are similar to those of FIGS. 2 and 3.
• the thermoplastic material can be applied to the open fibers 10 not only in the powder state, but also in the molten liquid state or in the solid state suspended in a liquid.
• the application of the thermoplastic material will be made by licking.
• the installation comprises a licking device 53 disposed on the vertical path of travel of the open bundle 1 downstream from the unit or units for opening the bundle of fibers 1.
• This device 53 comprises a tray 54 whose the bottom is provided with a heating system 55 and which contains molten thermoplastic material 56.
• a wetting roller 57 carried by the tank 54 partially dips into the liquid material 56 and transfers by continuously rotating a layer of liquid thermoplastic material to a wetting roller 58 which is carried by said tank 54 and which, on the one hand, is in contact with the periphery of the wetting roller 57 and, on the other hand, is pressed against the bundle of open fibers 1, the speeds peripherals of the two rollers 57, 58 being equal to the speed of travel of said bundle 1.
• the licking device 53 may include, instead of the tray 54 and the rollers 57, 58, a material extruder thermoplastic or two extruders facing each other, the open bundle of fibers licking the tip of the single extruder or the tips of the two extruders between which said open bundle passes 1.
• the impregnation of the open fibers 10 with thermoplastic material can also be made with such a material in powder or liquid form and containing, as fillers, a certain proportion of short fibers which can be of any kind.
• thermoplastic material in powder or liquid form and containing, as fillers, a certain proportion of short fibers which can be of any kind.
• thermoplastic material As previously mentioned, it is possible to bring the fibers open after the impregnation thereof with thermoplastic material, this reconciliation or reassembly being done in such a way that the fibers are not linked together by the thermoplastic material.
• a transverse application to the bundle of fibers impregnated with compression forces is applied, for example using a compacting device as shown partially and schematically in FIG. 8.
• This device comprises a succession of pairs of compacting rollers 59 to 64 having peripheral grooves which, for each pair of rollers in mutual contact by their external cylindrical faces define, in a plane perpendicular to the axis of the fiber bundle, passage sections 59a to 64a which are alternately round and oval (and elongated either vertically or horizontally) and whose surfaces decrease from one pair of rollers to the other from upstream to downstream in the direction of travel of the bundle of fibers.
• Another variant of the compacting device can consist of a roller box comprising two pairs of rollers with peripheral grooves 65, 66 and 67, 68 arranged one behind the other, the parallel axes of the first pair of rollers 65, 66 being perpendicular to the parallel axes of the second pair of rollers 67, 68, but offset therefrom by a distance equal in diameter to the rollers.
• thermoplastic material It has proven advantageous to subject one or more bundles of fibers impregnated with thermoplastic material to a pultrusion operation while the thermoplastic material is still fluid, that is to say before the latter is cooled. This avoids an operation of reheating the bundles of impregnated fibers which is absolutely necessary if the pultrusion is carried out from an impregnated and stored bundle.
• Pultrusion which is a kind of compaction in the case of bundles of impregnated fibers, can be carried out in a pultrusion device 69 comprising, for example mounted in series, two ultra-hollow dies 70, 71 whose number of holes is equal to one die to another, but the diameter of the holes is smaller on the downstream die 71 than that of the holes of the upstream die 70 and the holes of the downstream die 71 are distributed over a smaller area than the holes of the upstream die 70 and are closer to each other and to the axis of the sector than those of the upstream sector.
• the different bundles of fibers have been sufficiently compacted and brought together, they can pass through a single-hole die for their assembly into a final product (see FIGS. 10a, 10b, 10c).
• the final fibrous product can also be in the form of a sheet.
• thermoplastic material it may be advantageous to form a sheet of fibers from a plurality of bundles of continuous fibers impregnated with thermoplastic material, to conform this sheet into a cylinder 75 using a weakly frustoconical die 76 during that the thermoplastic material of this sheet is in the plastic and heat-bonded state and to cover a longitudinal edge 75a of this sheet shaped as a cylinder by the other longitudinal edge 75b and to adhere said pressure to each other under said pressure 75a, 75b (see Figure 12).
• the latter can be surrounded with a cold strip 76 produced from at least one bundle of continuous fibers impregnated with thermoplastic material.
• the ribbon is placed around the cylinder 75 preferably so that the parallel fibers of the ribbon 76 include with those of the cylinder 75 an angle between 15 and 87 °, while retaining the general shape of a cylinder.
• said ribbon 76 is heated to a temperature allowing heat bonding between the thermoplastic material of the cylinder 75 and that of the ribbon 76 (see FIG. 13).
• impregnation material covering each of the parallel fibers is in the molten state, or more generally, in the plastic and deformable state, it is possible to repeat the operation of separation or opening of the fibers of the manner described in conjunction with one of Figures 1 to 4 and solidify the impregnation material before parallel delivery of the long continuous fibers.
• the bundle 1 passes through the opening means 9 and the impregnation means 11 in which the long continuous fibers are separated, for example in a bird cage and receive the material d 'impregnation between and around the fibers thus separated; then the bundle of parallel long continuous fibers passes through a compacting device 59 to 64; then in a heating oven 21 to reduce the viscosity of the impregnation material and therefore the cohesion between the parallel fibers; then again by opening means 27, with the aid of which the parallel fibers are again separated, the impregnation material solidifying while the fibers are separated, thus avoiding any cohesion between the long continuous fibers coated with the material impregnation.
• Figure 15 there is shown very schematically the different means entering an installation for implementing a method according to the invention, this installation comprising in the direction of travel of the fiber bundle: - a storage reel 2 at least one bundle of parallel long continuous fibers;
• a preheating system 77 whose purpose is to remove moisture and possibly destroy or modify products used to bond the parallel fibers together, to facilitate transport and handling;
• a shaping device 28 making it possible to obtain the desired shape and length of the final fibrous product

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Citations (6)

• 1990
  • 1990-04-11 EP EP90907102A patent/EP0466830A1/de not_active Withdrawn
  • 1990-04-11 WO PCT/FR1990/000262 patent/WO1990012141A1/fr not_active Application Discontinuation

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