Abstract
A process for the manufacture of an elongate composite element comprising a bundle (20) of multifilament fibers embedded in a composition based on a polymerizable substance comprising the following comprises: arranging multifilament fibers in the form of several individual strands, so that a first strand (20a) is located at the center of the bundle and that the other strands are positioned around the first strand; and carrying along the arrangement of multifilament fibers in order to subject it, in the direction of forward progression, to degassing of said arrangement of fibres by the action of vacuum, impregnation of the arrangement of fibres with the composition, passage of the first impregnated strand through a first die (10a) which carries out its partial polymerization, passage of all the strands through a last die (10f) which brings them together in a single strand (20f), and exposure of the single strand (20f) to a source of radiation in order to carry out an additional polymerization to obtain the elongate composite element.
Claims
1.-12. (canceled)
13. A process for continuous manufacture of an elongate composite element comprising a bundle (20) of multifilament fibers embedded in a composition based on a polymerizable substance comprising the following steps: arranging multifilament fibers of the bundle in a form of several individual strands, each comprising several multifilament fibers, so that a first strand (20a) is located at the center of the bundle and that the other strands are positioned around the first strand; and carrying along the arrangement of multifilament fibers in order to subject it, in the direction of forward progression, to: degassing of the arrangement of fibers by vacuum, impregnation of the arrangement of fibers with the composition in order to obtain impregnated strands, passage of the first impregnated strand through a first die (10a) which carries out a partial polymerization of the composition, passage of all the strands through a last die (10f) which brings them together in a single strand (20f), and exposure of the single strand (20f) to a source of radiation in order to carry out an additional polymerization so as to obtain the elongate composite element.
14. The process according to claim 13, wherein the arrangement of the strands and the successive passages through at least the first and the last die are carried out so that the strands are brought to converge, starting from an impregnation chamber (3) at an outlet of which the arrangement is most expanded, toward the last die (10f) where the arrangement is contracted to form the single strand (20f).
15. The process according to claim 13, wherein the arrangement of multifilament fibers comprises a central strand, several intermediate strands positioned to form at least one intermediate layer surrounding the central strand and at least one outer layer of peripheral strands, in which each intermediate layer of intermediate strands passes through an intermediate die which carries out the partial polymerization of the composition.
16. The process according to claim 13, wherein a section of the elongate composite element is circular.
17. The process according to claim 13, wherein the multifilament fibers are selected from the group consisting of glass fibers, carbon fibers, silica fibers, ceramic fibers and mixtures thereof.
18. The process according to claim 13, wherein the polymerizable substance is a thermosetting type substance.
19. A device (1) for continuous manufacture of an elongate composite element comprising a bundle (20) of multifilament fibers embedded in a composition based on a polymerizable substance, comprising: means configured to produce an arrangement of multifilament fibers of the bundle in the form of several individual strands, each strand comprising several fibers, so that a first strand (20a) is located at the center of the bundle; means for degassing the arrangement; means for impregnation of the arrangement with a composition based on a polymerizable material; a first die (10a) capable of receiving the first strand (20a) to conduct partial polymerization; at least one last die (10f) capable of receiving all the strands in order to form a single strand (20f); and means for polymerization of the single strand using a radiation device (50) so as to obtain the elongate composite element.
20. The device according to claim 19, further comprising at least one intermediate die (10b-10e) located between the first die (10a) and the last die (10f).
21. The device according to claim 20, wherein the first die (10a) and the intermediate die (10b-10e) comprise annular UV radiation lamps (30) comprising, in their central part, a guide tube (40) for a strand.
22. The device according to claim 21, wherein the annular lamp (30) comprises a disc (32) for supporting several light-emitting diodes provided with a central opening through which the guide tube (40) passes, and a reflector (33) capable of sending radiation emitted by the light-emitting diodes in a direction of the outlet of the guide tube, means for cooling the lamp and means for supplying the lamp with electricity.
23. The device according to claim 22, wherein the cooling means comprise a water cooling circuit, a device for producing an air or nitrogen flow, or both.
24. The device according to claim 21, wherein an internal section of each guide tube (40) gradually increases from upstream to downstream between the first die (10a) and the last die (100.
Description
[0037] FIG. 1 is a perspective view illustrating the components of a device for the manufacture of an elongate composite element according to a preferred embodiment of the invention;
[0038] FIG. 2 is a diagrammatic perspective view illustrating the main components of another embodiment of the device of the invention;
[0039] FIG. 3 is a sectional view on an enlarged scale of the feature A of FIG. 2;
[0040] FIG. 4 illustrates by a perspective view on a larger scale the device of FIG. 1;
[0041] FIG. 5 illustrates the right part of the device of FIG. 4 on an enlarged scale;
[0042] FIG. 6 is a sectional view of a die forming part of the device of the invention;
[0043] FIG. 7 illustrates by a perspective view on an enlarged scale a piece forming part of the cooling circuit of a lamp forming part of the die of FIG. 6.
[0044] In the various figures, identical or similar elements carry the same reference. Their description is thus not systematically repeated.
[0045] FIG. 1 diagrammatically illustrates a device 1 for the manufacture of an elongate composite element of great length. In the example illustrated in the figures, this composite is a GRC single strand comprising glass filaments embedded in a thermosetting resin. The single strand can take any known shape; it can, for example, be a cylindrical single strand of large diameter, for example ranging up to 10 to 30 mm, thus having a cross section of circular shape. The device of the invention makes possible, of course, the manufacture of single strands of rectangular, oval or other cross section. The glass filaments are present in the form of essentially unidirectional multifilament fibres each formed of a plurality of unitary glass filaments each having a mean diameter of the order of 5 to 30 The resin is of the thermosetting or crosslinkable type is understood to mean that the resin is polymerizable or curable (photocurable and/or thermosetting) by being based on a thermosetting polymer. The glass transition temperature of the resin Tg is preferably greater than 160 C., more preferentially greater than 170 C., in particular greater than 180 C.
[0046] In FIG. 1, there is observed a bundle 20 of multifilament fibres which enters the device 1, the bundle being represented diagrammatically in the other figures by an arrow E, the direction of which indicates the direction of forward progression of the bundle with respect to the device 1, which is itself fixed. The bundle 20 enters the device through an inlet plate 4 into a vacuum chamber 2, in the form of several strands of multifilament fibres continuously unwound from different reels 9 of a feed device 8. In general, the fibres are delivered in rovings, that is to say in groups of fibres wound in parallel on a reel and identified by their Tex code. The bundle, originating from the feed device 8, passes through the device 1 by progressing in the direction of the arrow E, being set in motion by a drive device located at the outlet of the device 1 (it is understood after the outlet of the radiation device 50, indeed even the direction of the arrow S, as will be explained later). The drive device (not represented) is, for example, of the type comprising a motorized traction drum making it possible to wind the composite element around its axis or comprising two motorized drums facing each other, being spaced apart by a distance corresponding at least equal to the thickness of the composite element, and which rotate in opposite directions to carry along the composite element, by friction, in a translational movement, passing it through the space located between the two drums. The device 1 successively comprises: a vacuum chamber 2, an impregnation chamber 3 and two dies 10a and 10b called polymerization dies, a last die 10f, called the calibration die, through which passes the single strand 20f finally obtained, and a radiation device 50 for it. Radiation device 50 is understood to mean a UV and/or IR radiation device which carries out the additional, preferably final, polymerization of the single strand exiting from the last die 10f.
[0047] There are observed, in FIG. 2, the main components of the device 1 according to another embodiment of the invention which successively comprises: a vacuum chamber 2, an impregnation chamber 3 and several dies 10a to 10e called polymerization dies. The last die 10f, called the calibration die, and also the radiation device 50, which is positioned before the exit of the device, are visible in FIG. 4. The vacuum chamber 2 is delimited axially by a rigid inlet plate 4, provided with through-holes, and a rigid separation plate 5, also provided with through-holes which are located axially opposite those of the plate 4. The fibres, divided into several strands, are introduced into the vacuum chamber by making them pass through the various orifices of the plate 4 and exit from it through the orifices going through the plate 5 so that the strands travel paths which are linear and parallel to one another from one plate to the other while being parallel to the longitudinal axis X-X of the device. The vacuum chamber is connected to a vacuum pump (not represented) which maintains a pressure level of approximately 0.1 bar in the vacuum chamber 2, despite the passage of the fibres through openings having diameters greater than those of the strands going through them. The impregnation chamber 3 is a sealed enclosure, delimited by the intermediate plate 5 and by a rigid outlet plate 6, also provided with through-holes 7 located axially opposite those of the intermediate plate 5. The number of orifices 7 corresponds to the number of strands which make up the bundle 20. The impregnation chamber is fed with resin originating from an external tank (not represented) via an inlet pipe (not represented) on the top, the chamber also comprising, on the bottom, a pipe (not represented) for discharge of the resin. The impregnation chamber 3 is totally filled with resin so that the fibres exiting from the vacuum chamber 2 pass through it while following paths which are linear and parallel to one another and are completely impregnated with resin.
[0048] It is of course necessary, before putting the device 1 of the invention into operation, to pass all the strands of the bundle to be impregnated, starting from storage reels 9, while passing through the orifices of the plates 4, 5 and 6, through all the dies and the radiation device 50 and up to the drive means which ensures the tensioning of all the strands of the bundle according to a pre-established arrangement of multifilament fibres.
[0049] By way of example, if it is desired to obtain a cylindrical composite element having an external diameter of 19 mm, using a device presented in FIGS. 1, 4 and 5, an arrangement of approximately 80 elementary bundles of multifilament fibres is used, each of these 80 elementary bundles arriving in the device from a reel 9 of 4800 Tex roving. The arrangement of the 80 elementary bundles is made as follows: a central strand with a diameter of 5.6 mm, itself consisting of an assembly of 8 elementary bundles of multifilament fibres originating from 8 reels of 4800 Tex, and 2 additional rows concentric with the first, the radial thickness of each row of which is approximately 3 mm, each row comprising several concentric strands, the first additional row consisting of 3 strands themselves consisting of 8 elementary bundles originating from 8 reels of 4800 Tex, the second additional row consisting of 6 strands themselves consisting of 8 elementary bundles originating from 8 reels of 4800 Tex, the whole clearly giving a total of 8+38+68=80 reels of 4800 Tex.
[0050] Downstream of the impregnation chamber 3 are found the polymerization dies 10a to 10e and a last calibration die 10f, all the dies being positioned along one and the same axis which is the longitudinal axis X-X of the device. The bundle 20 is composed of a plurality of strands, originating from the reels 9, forming an arrangement of strands intended to ensure a successive passage of these strands through the various dies of the device. The arrangement of the strands is organized so that the central strand passes through the first die 10a, positioned substantially in the axis of the device, the various intermediate strands being organized in successive rows surrounding the central strand, coaxially with the axis of the central strand, to gradually converge when they go through the dies 10b to 10e until all the strands are joined together to pass through the last die 10f (FIG. 4) and form a single strand 20f.
[0051] FIG. 4 illustrates a preferred embodiment of the device comprising a first die 10a, an intermediate die 10b and a last calibration die 10f. It is observed better, with reference to FIG. 5, that the bundle of multifilament fibres 20 comprises a central strand 20a and peripheral strands positioned concentrically to the first. The central strand 20a is intended to pass through the first die 10a which ensures its partial polymerization. The strand exiting from it and the peripheral strands 20ae pass together through an intermediate die 10b which ensures the partial polymerization of the new strand 20b thus formed. The strand 20b exiting from the intermediate die 10b and the remaining peripheral strands 20 be pass together through a calibration die 10f which shapes them in order to form a final strand 20f before the definitive polymerization of the latter which takes place in the radiation device 50. The calibration die 10f is a tube having a well-defined shape and dimensions. In an alternative form, the calibration die is of the polymerization die type.
[0052] A description will be given, with reference to FIGS. 3 and 6, of the structure of a polymerization die 10a. The die has an elongated shape of longitudinal axis A-A and it comprises an annular lamp 30 and a guide tube 40 for a strand of fibres which enters the die. The lamp and the guide tube are held together in a die body 45 in two parts 45a, 45b which is provided with fins for attachment 46 to the device 1. The die body is extended at its outlet end by a tube 41 which directs the bundle exiting from the die towards the following die. The annular lamp 30 is an assembly comprising several LEDs 31 having UV radiation which are connected to one another via a printed circuit on a common support 32 of annular shape centred on the axis A-A. The annular lamp 30 comprises a reflector 33 capable of sending the radiation emitted by the LEDs in the direction of the outlet of the guide tube 40. By way of example, the annular lamp 30 comprises several high-power LEDs emitting in the wavelength of between 365 and 410 nm, preferentially 385 nm, having a maximum electrical power consumed of between 100 and 500 W and requires cooling during its operation. The die presented in FIG. 3 comprises a liquid cooling circuit (for example water), whereas the die in FIG. 6 comprises an air or nitrogen cooling circuit. The die presented in FIG. 6 comprises a cooling circuit 35 for this purpose comprising an inlet 34 which connects it to a feed of air or nitrogen and a distribution plate 36 (FIG. 7) coming into thermal contact with the support 32. The distribution plate 36 comprises a distribution chamber 38 comprising internal walls forming baffles for the cooling gas, the path of which within the chamber and the die is represented by means of a line provided with arrows in FIGS. 6 and 7. The plate 36 furthermore comprises a central orifice 37 through which the guide tube 40 passes and orifices 39 for receiving the electrical connections of the lamp 30. The gas which was used to cool the distribution plate 36 subsequently emerges from this plate via the conduit 47, in order to subsequently be distributed in the annular chamber 48, then continues in the space provided for this purpose between the pieces 40 and 45a, in order to finally exit concentrically in the space made in the piece 45b along the direction indicated by the arrow G. This flow of gas thus has the dual purpose of first cooling the distribution plate 36 and then secondly of continually purging the interior volume of the piece 45b from any resin solvents in suspension or resin microprojections, and more specifically of guaranteeing the cleanliness of the reflector 33. The polymerization die 10a is positioned within the device 1 so that its longitudinal axis A-A is coaxial with the axis X-X of the device.
[0053] The die presented in FIG. 3 for its part has available two inlets 34 for gas, air or nitrogen, leading to an annular conduit 48, then to the interior space of the body 45 along the direction of the arrow G, targeting the same reasons of guarantee of cleanliness of the reflector 33. The die represented in FIG. 3 comprises, in addition to the die represented in FIG. 6, a feed 49 of cooling liquid, leading to a distribution plate (not represented) and then to a conduit 51 returning to the system for circulation and maintenance in temperature of the cooling circuit.
[0054] The first step of the process of the invention consists in producing an arrangement of multifilament fibres in several individual strands which form the bundle 20, at the time of its arrival in the device 1, each strand comprising one or more multifilament fibres. The arrangement is produced so that a first strand is positioned at the centre of the device, along the axis X-X of the latter, and several peripheral strands are positioned around the first strand. Use is made, for this, of an inlet plate 4 in a vacuum chamber 2 comprising several orifices for passage of the strands, including a central orifice and several peripheral orifices. This arrangement is subsequently passed through the separation plate 5 with an impregnation chamber 3 and the outlet plate 6 of the latter. The exiting strands from the impregnation chamber are subsequently passed through the various dies 10a, 10b (indeed even 10c, 10d, 10e for the device of FIG. 2) which each ensure a partial polymerization of the strand which passes through it. The last central strand exiting from the last die 10e passes through a final die 10f. The final die 10f only brings together all the strands at its centre in order to be able to pass the single strand 20f thus obtained through a radiation device 50 which ensures the final polymerization of the single strand. In an alternative form, the final die 10f is of the same type as the intermediate dies and carries out the final polymerization of the single strand 20f which passes through it.
[0055] Other alternative forms and embodiments of the invention can be envisaged in the scope of the invention as claimed. The process of the invention can be used with other types of multifilament fibres, indeed even with different types of fibres, within one and the same bundle.
[0056] Furthermore, it is possible to envisage the use of the splicing process and device of the invention with a thermally polymerizable organic substance.
[0057] It might also be possible to have a bundle delivered by a single reel at the inlet of the device and which is separated into several individual strands.
