FR2496552A1 - Applying adhesive coated flexible covers to series of rigid panels - a means of transferring adhesive - Google Patents

Abstract

In a process for applying flexible covers to one or both faces of a series of rigid panels, a continuous flexible sheet or film is applied tangentially to panels being supplied end to end and moving at a faster rate than the film to ensure that no gaps appeared between the panels. The film path is reversed so that a melt adhesive may be applied to the face of the film which is to contact the rigid panels. The film is subsequently cut along the junction between successive supports, so that covered panels can be collected as a stack. Suitable for applying siliconised paper to rigid panels as a means of applying and transferring the adhesive to the panel for subsequently mounting the latter. Avoids use of wet of solvent-based adhesive and associated drying/recovery operations. Use as continuous dispensing system to apply adhesive to discontinuous supports without risk of spillage or waste.

Description

 The subject of the present invention is an installation for the continuous production of products formed from a relatively rigid support made of cut sheets, and from at least one sheet made of flexible material supplied on a reel and laminated on one face of the support.

 The present invention also relates to a method of manufacturing a rigid self-adhesive material by means of the same installation.

 Currently, the coating or laminating of cardboard or paper is generally carried out manually, and, despite the simplicity of these processes, they are generally costly in time and in labor, because of the numerous operations and manipulations required.

 To overcome these drawbacks, and to laminate sheets on cardboard plates, an installation has already been proposed comprising two paths formed by. slides or continuous bands. In this installation, the horizontal path is taken by the cardboard sheet which passes under a glue-coating roller depositing an appropriate layer of glue. The sheet of paper to be laminated on this sheet of cardboard is taken from a magazine, and comes in a slide above the path taken by the sheet of cardboard. This slide is inclined so that the front edge of the sheet of paper reaches the front edge (in the direction of travel) of the sheet of cardboard blocked by a retractable stop. When the sheet of paper and that of cardboard are thus contact with each other, the stop is retracted and the conveyor belts can drive the sheet of cardboard, and consequently the sheet of paper towards the compression cylinders, the sheet of paper being driven by the sheet of cardboard of the made of its progressive bonding on the upper face of the cardboard sheet.

 This installation, although interesting because it replaces the manual work of placing a sheet of paper on a sheet of cardboard previously glued, is not satisfactory from all points of view and the installation works discontinuously, this which is a waste of time.

 Furthermore, it only allows laminating on one side at a time, which requires a second pass to make a cardboard laminated on both sides.

 In this installation, only a liquid adhesive at room temperature can be used, and therefore either a solvent adhesive or a water adhesive.

 Solvent adhesives have the drawback of releasing the solvent by evaporation, which can be inconvenient for the user of the machine.

 For this reason, currently only water-based adhesives are used. However, such an adhesive, even if it is spread in an extremely thin layer to prevent it from overflowing, destroys the hygrometic balance of the cardboard sheet, both by introducing part of this water and because the laminated sheet reduces the humidity exchange between the core of the cardboard sheet and the outside. This results in internal stresses causing the deformation of the assembly thus produced.

 Added to this is that products whose sheets are laminated with batten glue are relatively fragile because, when they are in humid places, the glue can soften and the sheet may come off at least partially.

 Finally, in some cases, when it comes to cartons on which are pasted drawing sheets, used for watercolors, depending on the artists' way of working and the humidity of the colors, this results in deformations not only of the sheet of paper but also cardboard or a takeoff of the sheet of paper.

 Furthermore, the glue currently used only allows laminating of a sheet of paper on a cardboard support. All other combinations of sheets made of materials other than those of paper or supports other than cardboard cannot be achieved.

 Performing lamination with a hot-melt adhesive would solve these various problems. Unfortunately, in this known machine, the distance which necessarily separates the coating area of the cardboard sheet from the contact area of this cardboard sheet and the sheet which is laminated, is of the order of 1 to 2m, which does not allow the use of a hot-melt glue (also called Holt Melt glue) because this glue would cool due to the too long open time and the thermal inertia of the cardboard, and would no longer stick.

 The object of the present invention is to remedy these drawbacks by proposing an installation making it possible to laminate the flexible sheets very effectively on an intermediate rigid cardboard, so as to obtain a product which is not very sensitive to variations in ambient humidity or the humidity of the products applied to the sheets, and which also make it possible to produce self-adhesive assemblies as well as the bonding of sheets or various supports such as metal sheets, for example, for precision work such as cartography, or the collage of a canvas on cardboard.

 To this end, the subject of the invention is an installation for the continuous production of products formed from a relatively rigid support and from at least one sheet of flexible material laminated to one face of the support.

 According to the invention, this installation is characterized in that it comprises, at least, a means of supplying at least one strip of flexible material comprising a cylinder on which the strip is wound t means of supplying support in form of plates capable of distributing plates at a predetermined rate to place them one after the other along a path in the installation t at least one first deflection cylinder for guiding the strip of flexible material towards the path of passage of the plates; a means for coating hot-melt adhesive capable of coating one of the faces of the strip of flexible material and placed directly upstream of the return cylinder; a group of pressing cylinders placed downstream of the first deflection cylinder on the continuous assembly passageway formed by the strip of flexible material and the laminated plates, and ensuring the entrainment of this assembly continuously t as well as a device for cutting synchronized with the supply of plates to cut the continuous assembly into products formed by a plate and at least one laminated sheet.

 This installation allows, in a very simple way, to make the lamination of two papers on a core of cardboard or rigid plastic, or even aluminum or even the coating or lamination of other materials such as canvas, decor paper, printed , plastic or metallic films.

 The presence of the cutting device which can, of course, be adjustable during each series of operations as a function of the characteristics of the desired final product, makes it possible to directly obtain the desired final product in a receiving unit without having any operation to perform manually.

 Furthermore, it is always easier to coat the continuous strip, and not the rigid plate, because if there was an interval between two successive rigid plates on the path of passage of the plates, the glue supplied by the means of coating (coating cylinder or nozzle) would come on the one hand on the opposing part of the machine and dirty it, and on the other hand, on the other side of the next plate, which would greatly affect the quality of the final product.

 According to another characteristic of the invention, the installation comprises two means for supplying two strips of flexible material associated with two coating means and two first deflection rolls for respectively bringing a glued strip towards the upper face and the face lower rigid plates.

 Of course, such an installation must be versatile, that is to say that it will not necessarily laminate strips of flexible material on both sides of the plates. In some cases (laminating fabric on a sheet of cardboard for example) laminating on one side of the plates may be sufficient or between the only operation sought.

 According to another characteristic of the invention, the means for supplying flexible strip material comprises at least one second deflection cylinder, placed upstream of the first deflection cylinder (s), the coating means being placed between the first and the second return cylinder.

 This arrangement makes it possible to tension the strip of flexible material optimally during the coating operation.

 According to another characteristic of the invention, the path of passage of the plates at the outlet of the plate supply means consists of a conveyor moving at a speed greater than the speed of travel of the strip.

 This arrangement makes it possible to push the plates edge to edge before they come into contact with the adhesive strip, so that there is no dead gap between two successive plates, which would risk causing a loss of glue. or soiling of parts of the installation which could come into contact with part of the glued strip which is not in contact with a plate, or else cause synchronization errors between the plate supply means and the cutting device.

 According to another characteristic of the invention, the plate supply means comprises a reserve of plates, in particular of cardboard previously cut out to predetermined dimensions, as well as an automatic distribution device, in particular with suction capable of distributing a plate according to a predetermined rate.

 According to another characteristic of the invention, each means for coating hot-melt adhesive comprises a coating nozzle placed between two support rollers coming against the opposite face of the strip.

 Of course, the coating nozzles which spread the hot-melt adhesive must have a width which corresponds to the width of the strips to be coated. It is necessary, under these conditions, a multiple supply in various places of the nozzle taken in the direction of the width.

 For example, the strips can have a width of 1 m: the nozzles must therefore have a corresponding width. However, to have optimal versatility of the installation, it is necessary that the large width nozzles also adapt to smaller bandwidths. For this, the coating means comprises shortening strips as associated with each of the nozzles whose ends they are capable of disabling to adapt the length of the coating slot to the width of the slot to be coated.

 Furthermore, it is necessary that the flow rate of the adhesive in the nozzles is adjusted as a function of the running speed of the strips to be coated, in order to spread on these strips a suitable thickness or quantity of adhesive per unit of area and a system of slavery is provided for this purpose.

 According to variants of the invention, the first return roller (s) may Xetre consist of heating cylinders, which prevent the hot-melt adhesive from cooling before the strips come into contact with the plates, or else by pressing cylinders.

 To have an optimal functioning of the installation it is particularly important to synchronize in a suitable way the distribution of the plates and the functioning of the cutting device, mainly for the transverse cutting, while the longitudinal cutting can be carried out in a simpler way, at by means of wheels.

 Mechanical synchronization between these devices is preferably ensured by mechanical means, and not by the detection of plate junctions at the level of the cross-cutting shears. The mechanical solution is, in fact, preferable because it is simpler; as, moreover, the machine is intended to treat cardboard plates or other supports, the dimension of which in the direction of travel is known and chosen once and for all (a few dimensions only) the interval which separates the means of dispensing plates and the cutting shears is known; under these conditions, it suffices to adjust the machine at the start of an operating phase so that it is adjusted for all operations.

 According to another characteristic of the invention, at least one of the means for supplying strips of flexible material comprises a printing device cooperating with the strip of flexible material upstream of the coating nozzles.

 The presence of this device allows any decoration (advertising brand, aesthetic decoration, etc.) to be produced on one or two strips of flexible material.

 The installation described above can also be used for implementing a process for manufacturing a self-adhesive cardboard; for this, the coating is carried out with a self-adhesive or heat-bonding product on a silicone strip, then this strip is applied to the rigid plates. The glue is transferred from the silicone strip onto the plates. During use, it is enough to remove the silicone band to have the sticky surface on the rigid plates.

The installation which is the subject of the invention will be described in more detail with reference to the accompanying drawings, in which
FIG. 1 is a schematic view of an installa tiai comprising a single means of supplying a strip of flexible material,
- Figure 2 is a diagram similar to Figure I, in which there are provided two means for supplying two strips of flexible material.

 According to Figure 1, the installation which is the subject of the invention and allows the continuous manufacture of products formed of a relatively rigid support and at least one sheet of flexible material laminated on one face of the support, comprises , schematically, a means for supplying a strip I of flexible material previously wound on a supply cylinder 1, as well as a supply means 2 for supports in the form of plates capable of distributing plates 11 of material relatively rigid at a predetermined rate, to put them one after the other along a substantially horizontal passage path III in the installation.

 The supply means 2 for plates It is constituted by a magazine 10 of plates 11 previously cut to predetermined dimensions, as well as an automatic distribution device, in particular with suction, not shown, capable of distributing a plate 11 at a predetermined rate. on the way of passage III.

 The strip I of flexible material coming from the cylinder 1 passes successively around a first return cylinder 3 and a second return cylinder 4, which guide it towards the path III of the plates II which are themselves guided by a conveyor 5.

 The installation further comprises a coating means 6 made of hot-melt adhesive, capable of coating one of the faces of the strip I. This coating means is placed between the first and second return cylinders 4, in an area where the strip I is suitably stretched. The coating means 6 comprises a coating nozzle 7 which is shown diagrammatically in the figure. This nozzle 7 is placed between two support cylinders 8 and 9 coming against the face of the strip I not coated by the nozzle 7.

 After having been coated by the nozzle 7 and directed via the return cylinder 4 towards the passage path III of the plates 11, the strip I is applied and glued to the plates II by means of pressure cylinders 12 and 13 .

 According to a variant not shown in the figure, the deflection cylinder 4 can constitute one of the presser cylinders 12 or 13, or be provided with a heating device to prevent the cooling of the adhesive distributed by the nozzle 7, before that -this arrives at the right of the pressing cylinders 12 and 13.

 I1 is particularly important that the speed vl of the strip I be lower than the speed v3 of the plates ll on the path III so as to push the plates 11 edge to edge before they come into contact with the strip I glued together opposite of the nozzle 7, so that there is no gap between the plates 11 which would then risk giving rise to a loss of adhesive, or to contamination of the various elements of the installation which may come into contact with the adhesive .

Downstream of the pressure rollers 12 and 13, the continuous assembly formed by the strip of flexible material I and the plates
It laminated is brought to a cutting device 14 constituted by longitudinal cutting means 15 constituted by knurling wheels which trim the edges of the strip and by a device 16 for transverse cutting. To obtain in the receiving unit 18, a final product 17 consisting of a plate
It and a laminated sheet having satisfactory characteristics, it is particularly important that the cross-cutting device 16 is synchronized by means of plate feeding 2. In order to simplify and to increase the reliability of the installation, this synchronization is ensured by mechanical means, and not by the detection of the junctions of the plates ll at the level of the shears 16.

 Furthermore, the flow rate of the adhesive supplied by a pump (not shown) in the nozzle 7 is adjusted as a function of the running speed vl of the sheet I to be coated, in order to spread on this strip a suitable thickness or quantity of adhesive per unit area.

As already indicated above, the nozzle 7 must have a width which corresponds to the width of the strip
I. It is necessary, under these conditions, to provide a multiple supply at various locations of the nozzle 7, in order to be able to coat sheets I whose width can go up to 1 m. To have optimal versatility of the installation, it is necessary that the nozzle 7 can also adapt to bandwidths
I less; for this, the coating unit 6 comprises shortening males not shown associated with the nozzle 7, the ends of which they are capable of disabling to adapt the length of the coating slot to the width of the strip to be coat.

 According to FIG. 2, the installation which is the subject of the invention comprises two means of supplying two strips of flexible material I and II which are originally wound on supply cylinders 1 and 1 ′, and are entrained by by means of return cylinders 3 and 4 on the one hand and 3 'and 4' on the other hand, towards the passage path III of the plates 11.

 In this case, the coating means 6 comprises two coating nozzles 7 and 7 'placed between two support cylinders 8, 9 on the one hand and 8' -, and 9 'on the other hand, coming against the face opposite of strip t and II in front between plaster.

 After having been coated opposite the nozzles 7 and 7 ′, the strips I and II are brought respectively to the upper face and the lower face of the plates II on the passageway III, and, the assembly thus formed is, as previously , brought between the pressing cylinders 12 and 13 to form a continuous assembly which is led to the cutting device 14 for between being cut into products formed from a plate 11 comprising a sheet laminated on each of its two faces.

 The change of the rollers I and 1 ′, when they are empty, is done in a very simple way: for this, it is enough to extract the support of the roll not shown in a direction perpendicular to the plane of the figure to release the empty roll and its support for the layers I or II, then, to put in place a new roller on which a band I or II has been wound, and to pass this new band around the cylinders 3 and 4 or 3 'and 4', etc. ...

 When changing a roll 1 or 1 ′, a support plate 11 is always lost, since the end of a strip I or II cannot correspond to the rear edge of a plate II. However, this loss is negligible in the operation of the installation. I1 is not necessary to have, in the magazine 10, a stack of plates 11 corresponding to the length of the strips I or II wound on the cylinders 1 or 1 ′, due to the different thickness of the plates II of a on the one hand and bands I and II on the other. Slowing down, stopping and restarting do not present any difficulty because of the enslavement of the adhesive flow to the speed of the machine.

 Furthermore, provision may be made to add to the installation, object of the invention, a device 19 intended for printing one of the strips II of flexible material. This device 19 is located upstream of the cylinder 3 'and the nozzle 7'.

 The installation described above can be applied to the manufacture of all types of laminated products, and in particular to the manufacture of a self-adhesive product: for this, the self-adhesive glue is coated using of 11 one of the nozzles 7 or 7 ′ on a silicone strip I or II, then this strip is applied to the rigid plates 11. The adhesive then transfers from the silicone strip to the plates. In use, it suffices to remove the silicone band to have the sticky surface on the plate.

Claims (14)

 10) Installation for the continuous production of products formed from a relatively rigid support, and from at least one sheet of flexible material laminated to one face of the support, characterized in that it comprises at least one means for supplying the at least one strip (I) of flexible material comprising a cylinder (1) on which the strip is wound; a supply means (2) in the form of a plate support, capable of distributing plates (11) at a predetermined rate to place them one after the other along a passage path (III) in the installation: ; at least a first deflection cylinder (3) for guiding the strip of flexible material towards the path (III) of the plates (11); a means for coating (6) hot-melt adhesive capable of coating one of the faces of the strip (I) of flexible material and placed directly upstream of the return cylinder (4); a group of pressing rollers (12, 13) placed downstream of the first deflection cylinder (3) on the passageway (III) of the continuous assembly formed by the strip of flexible material (I) and the plates (11) laminated, and ensuring the drive of this assembly continuously t as well as a cutting device (14) synchronized with the supply of plates for cutting the continuous assembly into products formed of a plate and at least one sheet laminated.  20) Installation according to claim 1, characterized in that it comprises two means for supplying two strips of flexible material associated with two coating means and two first return cylinders for respectively bringing a glued strip towards the upper face and the underside of the plates.  30) Installation according to any one of claims 1 and 2, characterized in that the means for supplying flexible strip material comprises at least one second deflection cylinder placed upstream of the first deflection cylinder (s), the device d coating being placed between the first and the second cylinder.  40) Installation according to any one of claims 1 to 3, characterized in that the path of passage of the plates at the outlet of the plate supply means is constituted by a conveyor moving at a speed greater than the running speed Of the band.  50) Installation according to any one of claims I to 4, characterized in that the plate supply means comprises a reserve of plates in particular of cardboard previously cut to predetermined dimensions, as well as an automatic distribution device in particular to suction capable of distributing a plate at a predetermined rate.  60) Installation according to any one of claims 1 to 5, characterized in that each means for coating hot-melt adhesive comprises a coating nozzle placed between two support rollers coming against the opposite face of the strip.  70) Installation according to claim 6, characterized in that each nozzle comprises multiple supply members arranged in various places so as to allow it to have a width corresponding to the width of the strip to be coated.  80) Installation according to any one of claims 6 and 7, characterized in that each coating means comprises shortening strips associated with each of the nozzles whose ends they are likely to put out of service to adapt the length of the slot the width of the strip to be coated.  90) Installation according to any one of claims 1 to 8, characterized in that the first return cylinders are heating cylinders.  100) Installation according to any one of claims 1 to 9, characterized in that the one or the first return cylinders constitute one of the pressing cylinders.  110) Installation according to any one of claims 1 to 10, characterized in that the synchronization device is a mechanical device.  120) Installation according to any one of claims 1 to 11, characterized in that, at least, one of the means for supplying the strip of flexible material comprises a printing device cooperating with the strip of flexible material upstream coating nozzles.  130) Installation according to any one of claims 1 to 12, characterized in that the cutting device consists of a longitudinal cutting device by wheels and a transverse cutting device synchronized with the rate of distribution of the plates.  140) A method of manufacturing a rigid self-adhesive material by means of the installation according to any one of claims 1 to 13, characterized in that the coating of a hot-melt adhesive is carried out on a silicone strip and then apply this strip to the support plates in such a way that the glue is transferred from the silicone strip to the rigid support.