FR2801613A1 - The composite fiber panel material has two outer layers with fiber bridges between them forming a gap for an intermediate insert of gas-filled chambers with a bonding agent to hold them together and embed the insert - Google Patents

Abstract

The composite fiber material is composed of at least two textile layers (8) which are essentially parallel, separated from each other by fiber bridges (27) bonded at their ends to each layer. At least one intermediate insert (28) is between the outer layers (8) and between the fiber bridges (27), using shrouding which define closed chambers containing a gas. The chamber shrouding (28) are of a flexible film material. They are held together by a string structure for insertion between the fiber bridges (27). The chamber shrouding can also be continuous sheaths along a longitudinal or lateral direction, or they are balls packed together at least in zones between the outer layers (8). The chamber shrouding (28) are hermetically sealed. The gas is compressed within the chamber shrouding. A second intermediate insert can be placed within the outer layers, as a reinforcement, using organic or inorganic filaments such as glass fibers, or animal or vegetable fibers. At least one outer surface is covered by a cladding. The panel is solidified by impregnation with a material which hardens, and preferably an expanding resin. An Independent claim is included for a manufacturing process for the multi-layer composite fiber panel (16). The composite fiber material is placed between two mold plates as two layers of fiber materials bonded together by an intermediate structure, incorporating a resin. The resin embeds the shrouded (28) chambers filled with a gas. The pressure applied by the two plates compresses the trapped gas while the composite structure hardens. A further Independent claim is included for a production assembly where a mechanical support structure (2) holds the outer layers (8) apart to form a gap between them. A needle system (19) forms the longitudinal bridges (27) between the layers (8) near the support. A guide (29) leads the intermediate insert between the outer layers (8) as they are advanced, using a structure of chambers with sealed shrouding (28) containing a gas.

Description

The present invention relates to a composite article consisting essentially of parallel fibrous webs associated with a structure of a fibrous web composite, method and apparatus for obtaining such an article. binding, in particular but not limited to a stiffened article to form a composite panel.

The present invention also relates to device methods for obtaining such articles.

It is known from WO-A1-93 / 01342 a method a device for producing a composite article. We start from two layers that are converged each towards a face of a slatted table. The spaces between the slats form in the table slots through which the two sheets are assembled, for example by needling. In the lamellae are formed longitudinal ducts through which introduced between the two plies and between the connecting lines formed by needling intercalary component chosen according to the destination of the composite article. The purpose of the component is to stiffen the panel, to make it absorbing to reinforce it, to fill it with electrical cables, etc.

In many applications, the qualities required of an article such as a composite panel or a composite web are economy, lightness and strength.

The object of the present invention is to improve in this sense the composite article known from WO-A1-93 / 01342.

According to a first aspect of the invention, the composite article comprising at least two textile webs substantially parallel to one another and spaced apart from one another, fiber bridges connecting these two webs, and at least an intermediate component inserted between the plies and between the fiber bridges, is characterized in that the intermediate component comprises envelopes defining chambers enclosing a gas.

According to the invention, the bonding structure between the at least two plies is partially hollow. Thus, the weight of the article per unit area is reduced for a given thickness and / or mechanical strength, and the cost is likewise reduced.

properties that such an article may have depending on the applications are very numerous. For example, the article may have thermal insulation, buoyancy, etc. properties.

the article is impregnated with a material capable of setting, such as a binder or a resin, a substantial economy of resin is achieved since the chambers defined inside the envelopes are not invaded by the resin and remain hollow in the final product which is therefore particularly light in relation to the mechanical strength it offers.

By compressing the panel during the setting of the resin, the spaces available for the resin are further minimized, the gas is pressurized and the envelopes deformed, all resulting in a prestress which further increases the rigidity of the panel obtained.

According to a second aspect of the invention, the method for producing a composite panel in which is placed between two forming plates a composite article comprising two elementary fibrous webs associated by a connecting structure at least partially composed of a material capable of forming in particular a resin, is characterized in that the material traps envelopes defining gas-filled chambers, and in that by compressing the composite article between the plates the gas is pressurized in the chambers during setting of said material.

According to another aspect of the invention, the method for producing a composite article, in which at least two elementary layers are connected to each other along longitudinal connection lines by maintaining them, where the process of connection, spaced apart from each other by mechanical action between the connecting lines being formed and as the two layers are connected is guided between them at least one intermediate element to introduce it into defined longitudinal spaces between the longitudinal connection lines by said mechanical action, characterized in that introduced as interposed component envelopes enclosing one so as to form an article according to the first aspect.

As reinforcing fibers, especially organic or inorganic, such as glass fibers, or animal or vegetable fibers, such as flax fibers, may be introduced between the plies as the second intermediate component. These fibers will thus be integrated into the article without being directly involved in the bonding process between the two layers. This is advantageous because some fibers, especially glass fibers, are difficult to needle.

The envelopes are preconstituted before being introduced as an intercalary component. They are preferably sealed so as to form sealed chambers in which air or other gas permanently enclosed. The envelopes may for example be constituted by two ribbon-shaped films glued against each other except on certain circular surfaces for example where the two films deviate from one another to form "bubbles".

It may also be a tubular film defining inside a continuous cylindrical general shape chamber, or preferably a tubular film having in place transverse welds isolating each other successive individual chambers. It may also be foams or particles such as beads that are introduced in bulk between the two layers or in certain longitudinal corridors formed between the two layers. Various expanded synthetic materials can be used for beads or foams such as polystyrene, polyethylene, PVC or polyurethane. Mineral materials can also be used such as glass or clay.

According to yet another aspect of the invention, the device for manufacturing a composite article, comprising means for guiding at least two elementary sheets parallel to each other, with mechanical means for defining a distance between them, means for connecting the two plies along longitudinal connecting lines in the vicinity of said mechanical means, and introducing means for guiding at least one intermediate component between the two plies as they advance parallel to each other to introduce this constituent in longitudinal corridors defined by the mechanical means between the longitudinal connection lines, is characterized in that the introduction means comprise means for guiding as interlayer envelopes defining chambers filled with a gas.

Other features and advantages of the invention will become apparent from the description below, relating to limiting examples to the accompanying drawings: - Figure 1 is an elevational view of a manufacturing device according to the invention; FIG. 2 is a view of a detail of FIG. 1, on an enlarged scale; Figure 3 is a sectional view taken along line III-II of Figure 2; - Figure 4 is a sectional view along IV-IV of Figure 2; - Figure 5 is a schematic cross-sectional view of the article obtained at the outlet of the slat table; - Figure 6 is a cross sectional view of the article obtained after forming; - Figures 7, 9 and are schematic views in longitudinal section of three different embodiments for the envelopes defining the chambers; - Figures 8 and 10 are partial perspective views envelopes of Figures 7 and 9 respectively; - Figures 12 and 13 are views similar to Figures 1 and 3 respectively, but relating to a second embodiment; - Figures 14, 15, 17 are views similar to Figures 1, 2, 3 and 4 respectively, but relating to a third embodiment As shown in Figures 1 and 2, the device according to the invention comprises a supporting frame 1 rigidly a vertical table 2 having two opposite guide faces 3.

As shown in FIG. 3, the table 2 is formed of lamellae 4. The lamellae 4 have an elongation direction which is vertical in the example (FIG. 2), have a flattened rectangular profile in planes perpendicular to the guide faces. 3, which are defined by the small faces or edges of the slats.

The <SEP> frame <SEP> 1 <SEP> includes <SEP> still <SEP> of <SEP> means <SEP> for
<tb> support, <SEP> of <SEP> share <SEP> and <SEP> of other <SEP> of <SEP> plan <SEP> of <SEP><SEP> table <SEP> 2,
<tb> two <SEP> coils <SEP> 7 <SEP> supply <SEP> in <SEP> layers <SEP> of <SEP> fibers
<tb> textiles. <SEP> The <SEP> web <SEP> 8 <SEP> supplied <SEP> with <SEP> each <SEP> coil <SEP> 7 <SEP> can be composed of randomly distributed fibers, for example by the technique called "Pneumatic nappage", or fibers having predetermined general orientations, obtained for example by means of a lapping spreader. These sheets may be consolidated or preconsolidated in known manner, in particular by needling or pre-needling. The frame 1 still carries various means 9, 11, 13 which will not be described in detail, intended to converge the two sheets 8 to the table 2.

The two sheets 8 (Figure 2) join the table 2 at the same height 31 and are guided parallel to each other downwards, each between a guide face 3 of the table 2 and a counterplate 14.

Downstream of the table 2 and the plywoods 14, the outgoing product 16 comprising the two plies 8 associated by a connecting structure as will be described later, passes between two drive rollers 17 rotating in opposite directions to pull the product 16 and therefore the two layers 8 along the route just described.

Each counter plate 14 is located between the table 2 and a respective needle board 18. Each plate 18 carries vertical rows of needles 19 oriented perpendicular to the guide faces 3 of the table 2. As shown in FIG. 3, the needles 19 are arranged in correspondence with slots 21 of the plywoods 14 and with gaps 22 , relatively narrow, between the lamellae 4. In the example shown, the rows of needles 19 are grouped in pairs. Each group of two rows of needles 19 is associated with two intervals 22 defined between a group of three lamellae 4. This pattern of needles 19 and slats 22 is repeated at intervals <U> here </ U> regular depending on the width of the table 2 with between two successive patterns a zone without needles or lamellae. There is thus a corridor 23 between the lamellae of two successive patterns.

In a manner not shown, the needle boards 18 are each connected to a known type of mechanism for needling machines, intended to animate these needle boards reciprocating back and forth 24 in a direction perpendicular to the guide faces This movement alternately penetrates the needles 19 between the lamellae 4 to beyond the guiding face 3 opposite the needle board 18 considered, then remove the needles from the lamellae table 2.

FIG. 4 illustrates that the lamellae 4 of the same pattern can be made in one piece with a common support 26 located upstream.

Figure 5 illustrates fiber bridges 27 each made by the work of the needles 19 in one of the gaps 22 between two neighboring lamellae. Each bridge 27 visible in FIG. 5 corresponds to a row of bridges or connecting line between the two plies, oriented longitudinally with respect to the direction of travel along the table 2. The penetration of the needles 19 into the table 2 causes fibers of the web 8 closest to the needle board considered and interleaves these fibers with those of the other web 8. The penetration of the needles on the other side of the table can be simultaneous if the needles are shifted by one board to the other, or otherwise alternated in which case the needles of the two boards can be exactly aligned. During the penetration of the needles, the guiding surfaces 3 defined by the edges of the lamellae prevent the plies 8 from being driven by the needles. During the withdrawal movement of the needles 19, it is the plywoods 14 which prevent the plies 8 from being driven by the needles 19.

An intermediate component 28 is inserted between the two plies 8 in the corridors 23 defined between the lamella patterns 4. Thus, as shown below in FIG. 2, this component 28 is found in the product 16 trapped on the one hand between the plies. 8 and other part between the groups of bridges 27 were formed by needling.

According to the invention, the intermediate component 28 is composed of envelopes enclosing a blank which is more precisely shown in the example, these envelopes have the shape of balls of relatively small size, of the order of a millimeter or a few millimeters, which are hermetic, free relative to each other, and sent in bulk, by gravity, in the corridors 23 so as to fill them.

For guiding the balls 28, the table 2 is mounted in a contiguous manner between two plates 29 extending to the zone 31 where the two sheets 8 arrive, just upstream of the two plywoods 14. Thanks to the joining of the strips 4 of 4) in a single support 26 in a region located between the plates 29, the balls can not be housed in the needling gaps 22 between the lamellae 4 of the same pattern.

FIG. 5 shows in the right-hand part obtained in cross-section with the groups of bridges 27 and the balls 28.

The article 16 thus obtained may for example be subjected to a waterproofing treatment to form a floating wall an inflatable structure, or serve as a wall both structural and thermally insulating.

As illustrated in Figure 6, the product 16 may also be impregnated with resin. The resin will invade the entire space outside the envelopes formed by the balls 28. During the setting of the resin, the product is compressed in the direction of its thickness. This has the dual effect of reducing the available space for the resin and thus the amount of resin consumed as well as the weight of the finished product. In addition, the intermediate component 28 compensates for its compression in the direction of the thickness by a compression of the gas contained in the envelopes but also by a lateral expansion. This leads to deformation of the bridges 27 in the form of an arc. Thus, the bridges 27 are maintained under low mechanical tension the mutual approximation of the two main faces of the article 16 become composite panel.

The impregnation of resin can be done through the two main faces of the product 16.

Depending on the destination of the product, the impregnation of resin and pressing may be done after cutting the product 16 leaving the machine 1 in a mold comprising essentially two pressing faces, flat or shaped for a particular use of the panel, to get a shape board.

The impregnation and pressing steps can also be carried out continuously before cutting the product.

The resin used may be a thermoplastic, thermoformable, thermosetting resin, or an expandable resin, for example an epoxy resin resin. Expandable resins fill the gap better and give an even lighter final product. Figure 6 further illustrates that one can improve the finish of at least one of the faces of the article 16 by laminating a coating 30 on this face. In Figure 6, the coating 30 is shown slightly spaced from the corresponding face Article 16 for the sake of clarity.

Alternatively, one or more finishing coating could be not laminated but integrated into the product upstream of the web assembly operation, the injected resin then ensuring in this case the cohesion of the coatings.

FIG. 7 illustrates that it is possible to use as intercalary component instead of balls 28, a chain 28a of envelopes of generally cylindrical shape 31 separated by welds 32.

As shown in FIG. 8, the intermediate component 28a can be produced by means of a flexible plastic film tube inflated with air or other gas and that is closed at regular intervals by the transverse welds 32. The film can for example be plastic such as a polyethylene 7 / 100mm. If resin is subsequently injected, the film will be chosen according to the nature of the resin because it must be able to withstand the temperature of the exothermic reaction of the resin used.

In the example shown in Figures 9 and 10, the intermediate component 28b is made by means of two flexible films 33, ribbon-shaped, glued or adhered to each other except at certain regularly distributed locations longitudinally where one films 33 form pockets 34 closed by the other film and containing air or other gas. The method for producing such an intermediate component is similar to that used to make packaging films having "bubbles" of

padding <SEP> for <SEP> to <SEP> protect <SEP> packaged <SEP> object <SEP> for
<tb> the <SEP> shocks <SEP> during <SEP> the <SEP> transport.
<tb> In <SEP> the example <SEP> represented <SEP> to <SEP> the <SEP> figure <SEP> 11,
<tb> the envelope <SEP> 28c <SEP> is <SEP> a <SEP> simple <SEP> film <SEP> tubular <SEP> continuous
<tb> flexible. <SEP> By <SEP> report <SEP> to <SEP> realizations <SEP> of <SEP> figures <SEP> 7 <SEP> to <SEP> 10,
<tb> this <SEP> film <SEP> tubular <SEP> is <SEP> more <SEP> economic <SEP> but <SEP> a
<tb> the disadvantage <SEP> of <SEP> does not <SEP> not <SEP> hermetically <SEP> trap air or other gas. On the other hand a puncture of the tubular film affects a great length of the article being produced.

The embodiments of Figures 7 to 10 are advantageous because the rosaries 28a or 28b are positively driven with the article being produced. The same applies to the embodiment of FIG. 11. The balls 28 require, on the contrary, a monitoring for the proper filling of each passage 23. They may, on the other hand, be advantageous for giving the article a better compressive strength in the meaning of its thickness.

Figures 4, 5 and 6 illustrate the operation of the device of Figure 1 with the different types of envelopes 28c, 28a, 28b, 28 from the left of each figure, respectively. This is purely illustrative. In practice, the same type of envelope will be used in all corridors 23 for a given production.

The example of Figures 12 and 13 will be described only for its differences from that to Figures 1 to 11. The frame 1 comprises means 6a for supporting a third coil of ply 7a delivering a third web 8a. There are two lamella tables 2a arranged parallel to each other with an interval between them for guiding the web 8a. There are two separate arrivals of intermediate components for placing interleaved components between the core ply 8a and each of the two outer plies 8, respectively. The needles 19 in the maximum penetration position can reach the opposite outer ply 8 or on the contrary, preferably only reach the central ply 8a. In practice, the three-ply embodiment that has just been described serves in particular to produce articles of relatively large thickness without the need to give the needles a movement stroke corresponding to the entire thickness of the product.

The example of Figures 14 to 17 will be described only for its differences from that of Figures 1 to 4. Several changes, substantially independent of each other are shown.

On the one hand, in the machine of Figure 14, the article advances in a horizontal plane during its production. The movement of-and-coming 24 needles is vertical.

Moreover, in this embodiment, there are two types of corridors 23 and 23a. The corridors 23, of larger size, are as in the previous embodiment for the introduction of the intermediate components 28. The corridors 23a are occupied by resin injection nozzles 36 are fed from a reservoir 37 (FIG. 14) and a pump 38 and open between the two sheets 8 beyond the downstream end of the table 2 (Figure 17).

The resin 39 dispensed by the nozzles 36 comes to drown the sheets 8 and the gap between them except the chambers 41 defined inside the envelopes 28. As the product was impregnated at the parade just after the operation of needling and introduction of the complementary component, the product 16 can be subjected to the operation of setting the resin also parade. to this effect passes between two forming plates 42, possibly heating, the mutual distance is calculated to compress the product and give it an internal configuration similar to that shown in Figure 6. Extraction rollers 43 are provided downstream of the plates 42 Then, a chain saw 44 delivers the article 16 in individual panels 46 which are for example received on a stacking device which is only suggested. The resin 39 may be chosen from the same varieties as those mentioned above.

In the right part of Figure 16, the passage 23 is made in a manner similar to that described for previous examples, between two successive patterns of lamella 4. The corridor 23a located next door is made in a similar manner.

On the other hand, the other corridors are defined as the inner face of tubular lamellae of rectangular square sections 47, of which two opposite faces contribute to defining the guide faces 8 and two other opposite faces delimit some of the intervals intended for the needles. In this embodiment, the slat table is more expensive to produce but the plies are better guided and supported against efforts at needling.

It is advantageous for the nozzles 36 to be components of relatively low value which can be replaced independently of the table 2, in particular, where appropriate, tubular lamellae 36a of table 2 in which they extend.

Of course, the invention is not limited to the examples described and shown.

It is possible to equip a machine with vertical movement as that of Figures 1 and 12 with an injection of resin as described with reference to Figures 14 to 17. The downward vertical feed is an advantageous solution for the insertion of the intermediate component especially when it is composed of balls 28 or similar components inserted in bulk.

 It is possible to introduce in certain corridors less a second intermediate component, in particular reinforcing fibers, in particular organic or inorganic fibers, such as glass fibers, or animal or vegetable fibers, such as flax fibers, in place of certain envelopes or together with envelopes in the same lane. This is particularly advantageous if the product is then impregnated as it has been said.

The setting material may be in the form of a powder, for example a plaster, a cement, or may be an elastomer.

In place of the needling, it can be called stitching or welding step.

Compared to the example of FIG. 11, the tubular films can be inserted in the deflated state between two plies, then inflated before resinisation, at a pressure which determines the space left to the resin, and which may differ from one another. tube to another, to distribute the resin in larger quantities in less swollen areas. It can also achieve a flexible and inflatable and deflatable structure by mounting a valve at the end of each tube or a valve common to all tubes. The structure can be sealed against a sticky film such as PVC at least one side, usually on both sides.

 In the example of FIG. 4, there could be only one lamella 4 between the two needle rows associated with the same support 26. To make a single fiber bridge between two corridors, such as 28a, 28b, 28c There could be only one row of needles between two lamellae or without adjacent lamellae, the support 26 then remaining as a guide beyond the needles.

 At the same time as the envelopes, it is possible to introduce between the plies the resin, such as phenolics, in powder form. activates the powder through a passage in the oven, especially steam oven.

Claims (4)

<U> CLAIMS </ U> 1. Composite article comprising at least two textile webs substantially parallel to each other (8) and spaced apart from each other, fiber bridges (27) connecting these two webs, and minus one intermediate element (28). , 28a, 28b, 28c) inserted between the plies (8) and between the fiber bridges (27), characterized in that the spacer element comprises shells defining chambers (41 enclosing a gas. 2. Composite article according to claim 1, characterized in that the envelopes 28a, 28b, 28c) are flexible. 3. Composite article according to claim 1 or 2, characterized in that the envelopes (28a, 28b, 28c) are made of film. 4. Composite article according to one of claims 1 to characterized in that the envelopes (28a, 28b) are connected to each other in strings inserted between said fiber bridges (27), agencies in rows. . Composite article according to claim 1 or 2, characterized in that the envelopes are sheaths (28a 28c) which are continuous in a longitudinal direction of the article. . Composite article according to one of claims 1 to characterized in that the envelopes are balls (28) accumulated at least in zones between the layers (8). 7. Composite article according to one of claims 1 to characterized in that the envelopes, 28a, 28b) are hermetic. 8. Composite article according to one of claims 1 to 7, characterized in that the gas is compressed in the envelopes. 9. Composite article according to one of claims 1 to 8, characterized in that it comprises as a second intermediate component reinforcing fibers arranged between the fiber bridges (27). 10. Composite article according to one of claims 1 to 9, characterized in that it comprises on at least one side a finishing coating (30). 11. Composite article according to one of claims 1 to 10, characterized in that it is stiffened into a panel by impregnation of a material capable of setting. 12. Composite article according to claim 11, characterized in that the material is expandable resin. Process for producing a composite panel in which a composite article (16) comprising two elementary fibrous webs (8) associated with a connecting structure at least partially composed of a material (39) is placed between two forming plates (42) capable of setting, in particular a resin, characterized in that the resin traps envelopes (28, 28a, 28b, 28c) defining chambers (41) filled with gas, and in that by compressing the composite article ( 26) between the plates (42) the gas is pressurized in the chambers during setting of said material (39). 14. A method for producing a composite article, in which at least two elementary webs (8) are connected to each other along longitudinal connection lines by holding them there, where the binding process is carried out, spaced apart. one of the other by mechanical action between the connecting lines being formed, and as the two webs are connected, at least one intermediate component (28, 28a, 28b, 28c) is guided between them. introducing into longitudinal corridors (23) defined between the connecting lines, characterized in that gas-filled shells (28, 28a, 28b, 28c) are introduced as an intermediate component so as to form an article according to one of the The method according to claim 14, characterized in that the elementary webs (8) are brought on either side of a longitudinal lamella table (2), the longitudinal connection lines are formed ( 27) in definite spaces is between the slats (4), and the intermediate component (28, 28a, 28b, 28c) is introduced into longitudinal channels (23) defined by the slats (4, 47) so that the intermediate component is placed between the slicks elementary elements (8) and between the connecting lines (27). 16. The method of claim 14 or 15, characterized in that by nozzles (36) extending parallel to the slats (4, 47), is injected between the plies (8) at least one fluid or a powder that takes with at least one of the elementary webs by trapping the envelopes at the outlet of the nozzles. 17. The method of claim 16, characterized in that the fluid is chosen from: thermoplastic resins, thermoformable, thermosetting, plasters, cements, elastomers, expandable resins. 18. The method of claim 16 or 17 characterized in that downstream of the injection is compressed the article (16) between two forming plates (42 during setting process 19. 19. A method according to one of claims 14. characterized in that fibers are introduced as the second intermediate component between the plies (8) between the connecting lines (27) 20. The method according to one of claims 14 to 19, characterized in that, to connect the two elementary webs (8), use is made of a technique chosen from needling, sewing and welding 21. A device for manufacturing a particular composite article according to a method according to one of claims 13 to 20, comprising means ( 3, 4) for guiding at least two elementary webs parallel to one another, with mechanical means (2) for defining a distance between them means (19) for connecting the two webs (8) along lines of longitudinal connection s (27) in the vicinity of said mechanical means, and introduction means (29) for guiding at least one intermediate component (28, 28a, 28b, 28c) between the two plies (8) as they advance in parallel with each other; one to the other, for introducing this component into longitudinal channels (23) defined by the mechanical means 47) between the longitudinal connection lines, characterized in that the insertion means comprise means for guiding as the intermediate component of the envelopes (28, 28a, 28b, 28c) defining chambers filled with a gas. 22. Device according to claim 21, characterized in that it further comprises means for injecting into other longitudinal corridors (23a) defined by the mechanical means (2), material (39) capable of making contact with the webs. (8) by trapping the fibers of the plies, the connecting lines (27), and the envelopes (28, 28a, 28b, 23). The device according to claim 22, characterized in that the injection means comprise nozzles ( 39) each replaceably mounted in tubes (47) forming part of said mechanical means 24. Device according to one of claims 21 to 23, characterized in that it further comprises means (42) for pressing the article in the direction of its thickness downstream of the mechanical means, introduction means and injection means, relative to the direction of movement of the article (16).