GB2388607A

GB2388607A - Method of forming composite materials of unlimited length

Info

Publication number: GB2388607A
Application number: GB0211129A
Authority: GB
Inventors: Nadya Bevzyuk
Original assignee: STAR SYSTEM PRODUCTION Ltd
Current assignee: STAR SYSTEM PRODUCTION Ltd
Priority date: 2002-05-15
Filing date: 2002-05-15
Publication date: 2003-11-19
Also published as: GB0211129D0

Abstract

A composite material 2 of one or more layers of fibers and a curable resin is provided on a support table 1. At a portion C of the table 1, the composite is close to a vacuum device such as a porous mat 14 or flexible side roll 4 through which a vacuum is exerted to draw off air. At this point of the process, the resin is also cured by, for example UV or high frequency radiation, or preferably by heating form coils (16, fig. 3). After curing, the composite material is drawn past the portion C, such that an uncured length of the material now lies in portion C and the curing process is repeated to produce a material of potentially unlimited length. In the preferred embodiments, the resin can be an epoxy resin, polyester, vinyl ester, ferral or polypropylene, whilst the fibers are preferably carbon fibers, glass fibers, aramide fibers, natural fibers or polyester fibers, or a combination thereof.

Description

Method for realizing composite materials of unlimited length and device

applying such method.

5 The present invention relates to a method and a device for realizing composite materials of unlimited length.

By composite materials, in this case a combination of at least reinforcement fibers and resin is understood, 10 however, nothing excludes the application of other materials, too.

Methods for producing such composite materials of unlimited length are already known, however, these known 15 techniques show various disadvantages.

A first known technique consists in that the products to be realized are laminated in a continuous manner. Hereby, reinforcement fibers, which either are pre-impregnated 20 beforehand or are impregnated on site, are supplied in between substantially two endless conveyors, whereby the resin cures under pressure.

This technique is used in the first place for producing 25 laminates of unlimited length, more particularly flat and thin boards, such as these, for example, are applied for realizing side walls for refrigerator trucks and the like. 30 Subsequently, these flat boards can be heated and formed, such as, for example, for producing spare wheel boxes, undersides of cars, and such.

Such known device for producing composite material, 3S however, is extremely large and requires a very high investment.

Another known technique for realizing composites of unlimited length is formed by the so-called pultrusion technique. Hereby, reinforcement material is pulled through a resin bath or resin is projected onto the I 5 reinforcement fibers, after which the reinforcement fibers thus provided with resin are cured in a continuous-flow mould.

In this case, too, the disadvantage of the system 10 consists in that a very large space is required for applying this technique, and the investment is extremely high. Thus, the present invention has as its object a method 15 and a device for manufacturing composites of unlimited length which does not show the disadvantages of the known techniques. In fact, the invention relates to a device which is very 20 compact, which is very operationally reliable in that the control and progress of the curing is simple al.] can take place over a relatively small length and which requires only a minor investment.

25 Moreover, the device according to the invention has a very high flexibility, such that not only flat boards, but also profiles with the most differing shapes and dimensions can be produced by the same installation and with which boards, profiles or such of unlimited length, 30 as well as boards, profiles or such of a very small length can be manufactured. -

The composite materials as such can be further combined with any other materials, such as sandwich materials, 35 polypropylene, aluminium honeycomb structures, balsa wood, metal insertions, and such.

( The method according to the invention which shows the aforementioned and other advantages, substantially consists of a composite material, composed of at least one or more layers of fibers, which material is provided 5 with a resin and which is provided on a support or table; that a vacuum effect is exerted upon at least a length or part of the composite material; and that, after the curing of the composite material which is situated at the location of said part, the composite material is moved 10 over a distance which is smaller than or equal to the length of said part; in order to exert a vacuum effect upon that new part until the composite material, at the location of the last said part, has cured, and so on.

15 The device applying said method substantially consists of a table for supporting the composite material; and, next to and above the composite material to be cured, means which allow that the composite material, during curing, is subjected to a vacuum.

With the intention of better stowing the characteristics of the invention, hereafter, as an example without any limitative character, a preferred form of embodiment is described, with reference to the accompanying drawings, 25 wherein: Figures 1 and 2 in perspective, in two positions, represent the device according to the invention; figure 3, at a larger scale, represents a schematic 30 cross-section according to line III-III in figure 2; figure 4 represents a cut-open perspective of a particular composition of a composite.

In figure 1, the device according to the invention is 35 represented in its most simple form.

This consists of a working table 1 on which a composite material 2 can be provided, whereby this latter in this case consists of one or more layers of fibers which are provided with resin, for example, previously, or from a 5 device 3.

This table substantially consists of four parts, to wit a part A for supplying composite material 2; a part B for suctioning-off air: a part C for suctioning-off air and 10 curing the composite material, and a part D for transporting-off the cured material.

At the location of the parts B and C, at each side of the layer of composite material 2, an air-permeable roll, 15 flexible tube, mat or such shall be provided, 4 and 5, respectively, which, in the middle of the parts B and C, is connected to a flexible suction tube, 6-7 and 8-9, respectively. 20 These flexible tubes are connected to a common or separate vacuum pump.

The free extremities of the rolls, flexible tubes or such 4-5, in the parts A and B of the device, respectively, 25 are provided with a part of non-porous material, 10-11 and 12-13, respectively, which, so to speak, form closing parts of the roll, flexible tube or such 4, 5, respectively. 30 In this most simple form, the device according to the invention is completed by a layer of porous fabric 14 and a larger layer of foil or air-tight material 15, whereby the layer of porous material 14 has a width which is approximately equal to the dimension of the layer of 35 composite material 2 and has a length which is equal to the length of the porous part of the rolls, flexible

( tubes or such 4-5, whereas the air-tight foil 15 has a dimension which is equal to the entire length of the flexible tubes 4-5 with their respective parts 10-12 and 11-13 and a width which is clearly wider than said layer S of composite material 2, in such a manner that this layer or foil 15 around the composite material and around the rolls, flexible tubes or such 4-5 can be fixed air-tight at the table 1, by means of glueing, clamping or the like. At the location of the part C of the device, furthermore a heating device can be provided which, for example, consists of one or more electric coils 16 which are connected to a power circuit 17 with switch 18.

The functioning of the device according to the invention is very simple and as follows.

The composite material 2, which consists of one or more 20 layers of fibers of synthetic material, such as carbon fibers, glass fibers, aramide fibers, natural fibers, polyester fibers or any other reinforcement fiber or a combination of these fibers, is unwound, for example, from an appropriate supply roll and brought onto the 25 table 1, whereby the composite material, whether or not previously, for example, from a funnel 3, is provided with an appropriate quantity of resin, which can be formed by thermosetting synthetic resin, such as epoxy, polyester, vinyl esters, ferral, etc., as well as a 30 thermoplastic synthetic resin, such as, for example, polypropylene. Subsequently, the composite material 2 is provided on both sides with a porous roll, flexible tube, mat or such 35 4-5, onto which the draining pipes 6 to 9 are connected and after which, at the location of the parts B and C,

first of all a a porous layer of material 14 is provided, and over this layer an air-tight foil 15, which is larger than the layer 14 and is wider than the composite material 2, increased by the width of the flexible tubes, 5 rolls or such 4-5, in such a manner that this air-tight foil 15 at the sides of the composite material 2, more particularly beyond the rolls, flexible tubes or such 4-

5, can be brought into contact with the table 1 and can be connected to this table 1 in an air-tight manner by 10 clamping, glueing or the like, for example, by using a layer of double-sided tape which is provided at the lateral edges of the foil 15.

Subsequently, by means of the flexible tubes 6 to 9, a 15 vacuum will be created between the table 1 and the foil 15, as a consequence of which the composite material 2, so to speak, is compressed and can cure in this condition. By means of the layer 14 and the rolls or such 4-5, hereby the air still situated in between the layers 20 of fibers is removed.

The actual curing of the composite material 2 takes place at the location of said part C, whereby, at the location of this part C, a heating is realized, for example, by 25 means of one or more heating coils 16, in order to thus accelerate the curing.

It is clear that such curing also can be obtained by means of W radiation, high frequency or such. i In a particular embodiment, in fact above the part C a device can be provided for curing the resin, such as, for example, UV light, IR radiation and the like.

35 In the aforementioned method, the part B has the purpose to maintain the vacuum from after part C.;

This can take place by connecting separate vacuum pumps or two vacuum pumps or even one vacuum pump to the flexible tubes 6 to 9.

5 When the composite material 2 at the location of part C is completely cured, the layer 15 will be removed, after which the composite material is shifted over approximately a distance C, a layer 14 of air-permeable material and an air-tight foil 15 will be provided over lo the material, in the manner as described heretofore, after which the method is repeated, and so on.

It is clear that in this manner, an endless strip of composite material can be realized, which subsequently 15 either is cut to suitable lengths or not.

It is clear that, although in the example of figures l to 3 a flat layer of composite material 2 is represented, this composite material may show any shape, in 20 consideration of the fact that the layers 14 and 15 are deformable and can adapt to any profile of the composite material 2. This also means that according to the invention, composites can be realized which locally show a different shape in length and/or in width.

In figure 4, a particular composition is represented of a composite material which can be obtained according to the invention. 30 In this case, an air-tight foil 19 will be provided on the table l, on which foil subsequently an air-permeable fabric 20 is placed with thereupon the actual composite material which in this case is formed by laths of balsa wood 21 which possibly are connected to each other by 35 means of a temperature-resistant glue 22, and whereby on the balsa wood, a layer of carbon fibers 23 is provided

which are provided with resin and the fibers of which are positioned in the longitudinal direction of the composite material 2, in order to subsequently place a layer of reinforcement fibers 24 upon this layer 23, whereby said 5 reinforcement fibers are situated at angles of 45 and whereby this layer 24, too, is provided with resin.

Finally, a layer of air-permeable fabric 14 is provided on the thus formed composite material 2, over which said 10 layer, after the rolls, flexible tubes or such 4-5 have been provided, an air-tight foil 15 is placed.

From the preceding example, it becomes clear that the composite material, which can be manufactured in 15 unlimited length by means of the method and the device according to the invention, can show any composition.

Claims

Claims.

1.- Method for realizing composite materials of unlimited 5 length, characterized in that a composite material (2), composed of at least one or more layers of fibers, which material is provided with a resin, is provided on a support or table (1); that a vacuum effect is exerted upon at least a length or part (C) of the composite 10 material (2); and that, after the curing of the composite material (a) which is situated at the location of said part (C), the composite material (2) is moved over a distance which is smaller than or equal to the length of the part (C); and that a vacuum effect is exerted upon 15 this new part (C) until the composite material t2) at the location of (c) has cured, and so on.

2.- Method according to claim 1, characterized in that at the composite material (2) provided on the support or 20 table (1), along the lateral edges and/or on the upper side and underside thereof, over at least a length (C), porous rolls, flexible tubes, mats or such (4-S) are provided, onto which air-draining conduits (8-9-10-11) are connected which are in connection with a vacuum pump; 25 that the composite material (2), at the location of said part (C), is covered in an air-tight manner with an air-

tight material, such as a foil (15) or such; that at least the part (C) is subjected to a vacuum until the composite material (2) has cured at the location of (C); 30 that the composite material (2), after a possible removal of the air-tight material (15), and possibly of the rolls, flexible tubes, mats or such (4-), is moved over a distance of maximum the length (C), after which the method is repeated.

3.- Method according to claim 1, characterized in that

said vacuum effect is simultaneously exerted upon the parts (B) and (C).

4.- Method according to claim 2, characterized in that 5 between the composite material (2) and the air-tight material (15), an air-permeable layer (14) is provided.

5.- Method according to any of the claims 1 to 4, characterized in that, at the location of said part (C), 10 the composite material (2) is heated, radiated by means of UV light or any other technique, as a consequence of which the resin cures.

6.- Device applying the method according to any of the 15 preceding claims, characterized in that it substantially consists of a table (1) for supporting the composite material (2); and, next to and above the composite material (2) to be cured, means which allow that the composite material (2), during curing, is subjected to a 20 vacuum.

7.- Device according to claim 6, characterized in that the support or table (1) substantially is subdivided into four parts, to wit a supply part (A), an additional 25 sealing part (B), an actual curing part (C), and a support part (D) for the cured composite material (2).I 8.- Device according to claim 6 or 7, characterized in that at the location of the parts (B) and (C) of the 30 table (1), next to, below or above the composite material (2), porous rolls, flexible tubes, mats or such (4-5) are I provided, the length of which is equal to the length of said parts (B) and (C).

35 9.- Device according to claim 8, characterized in that the extremities of the rolls, flexible tubes, mats or!

such (4-5) are provided with sealing parts (10-ll and 12-

13). lo.- Device according to claim 8, characterized in that 5 the rolls, flexible tubes, mats or such (4-5) are provided with an air-draining conduit (6-7-8 and g).

11.- Device according to claim 6, characterized in that said means which allow tnat the composite material (2), 10 during curing, is subjected to a vacuum, are formed by at least an air-tight material (15), the length of which is equal to the length of the rolls, flexible tubes, mats or such (4-5), including their sealing parts (10-11-12-13), and whereby the width thereof is clearly wider than the 15 width of the composite material (2), increased by the dimensions of the rolls; flexible tubes, mats or such (4-

5), in order to be able to be connected, next to these rolls, flexible tubes, mats or such (4-5), to the table (1) and to be fixed at this table (1) in an air-tight 20 manner, for example, for clamping, glueing or such.

12.- Device according to claim 11, characterized in that between the composite material (2) and the air-tight material (15), an air-permeable layer (4) is provided, 25 the width of which is equal to the width of the composite material (2), increased by the dimensions of the rolls, flexible tubes, mats or such (4-5), whereas the length thereof is equal to the porous part of said flexible tubes (4-5).

13.- Device according to claim 7, characterized in that below the part (C) , a heating is provided, for example, in the form of electric coils (16).

35 14.- Device according to claim 7, characterized in that above the part (C), a device is provided for curing the

( resin, such as, for example, W light, IR radiation, and the like.