FR2527980A1 - Laminating transparent plastics film to packaging card - with openings for display, by applying film to outer face of card without contamination - Google Patents

Abstract

Machinery includes an applicator for applying an adhesive coating to one surface of the film and a roll nip mechanism for applying the adhesive film to the outer face of the supporting card following which the path of the coated card passes over a deflector rod bearing against the surface of the card. Esp., applicable to laminates requiring 20-24 g/m2 adhesive on e.g. polypropylene film 12-20 microns thick or (cellulose) acetate film 14-17 microns thick. Ensures that the entire film/card interface is adhesive coated. Requires less adhesive than processes in which the adhesive is initially applied to the relatively absorbant card layer. Ensures that the adhesive is not contaminated by direct contact with the machinery components until either laminated or until that on the window zones has sufficiently dried or hardened. Deflection with the film as the outer layer results in a taut combination of film and card. The external film layer smartens and protects the card layer and has the residual adhesive coating on the inner face of the pack.

Description

 The invention relates to a laminating machine. It will in particular find its application for applying a film of polypro pyrene or acetate on a cardboard support having cutouts. The entire film-coated cardboard support will in particular make it possible to produce packaging boxes comprising at least one transparent window through which it is possible to view the product located inside the box.

 Currently, there are a large number of laminating machines which make it possible to apply a polypropylene or acetate film on the front of a cardboard support generally previously printed so as to give the whole a shiny appearance. In the case where the film applied is polypropylene or other synthetic material, in addition, the final product obtained has the advantage of being waterproofed and moreover is much more resistant.

 This type of machine generally has a reel on which is stored the roll of film of width identical to that of the cardboard surface to be laminated; the machine has a gluing station which oerrnet to coat one side of the film with a regular layer of glue then, the glued film is applied to the cardboard support by means of two rollers between which the glued film is compressed on the front of the cardboard support the strip thus produced is cut and the cut cardboard supports can be shaped into boxes according to the use for which they are intended.

 This type of machine does not present great difficulties in production and gives satisfaction in their use.

 On the other hand, in the case of cardboard supports presenting cutouts, the machines of the preceding type cannot be used directly. Indeed, at the cutouts, the glued film no longer comes to be applied to a support and therefore represents an adhesive surface on which all the impurities present in the manufacturing workshop are bonded. And so, the resulting product absolutely does not fulfill its function since the window no longer exhibits perfect transparency and, the final product loses its attractive role.

 Consequently, at present, the production of transparent windows on the packaging boxes is obtained by coating the periphery of the cutout of the cardboard support with an adhesive compatible with the materials to be assembled, this coating being applied to the back of the cardboard support. Then, a film cut to the dimensions appropriate to the window it must cover is applied to the back of the cardboard support.

 In this case, the support is coated with glue and the film is simply applied to the back of the cardboard support. Gluing of the film cannot be used as explained above since the glued part of the film which is not applied to the support, is in contact with the open air and quickly becomes opaque. Otherwise. it would be extremely difficult to glue only the periphery of the film, which is in contact with the cardboard support.

 It would also be very unsightly to stick the film on the front of the cardboard sheet because then the bead of glue would be visible and then this would cause a surface deformation of the resulting product.

 In conclusion, current window packaging is expensive because it does not lend itself to automatic manufacturing and moreover requires large quantities of glue since the cardboard support coated with glue drinks a large part of the liquid glue.

 In addition, if one wishes to obtain a packaging benefiting from the properties provided by the exterior film-coating, it is necessary to carry out a double operation, namely placing the exterior film, then cutting the window and finally placement of an interior film window.

 This type of packaging is therefore currently little used despite its very attractive economic role for customers.

 The main object of the present invention is to present a laminating machine which is capable of applying a polypropylene or acetate film on a cardboard support having cutouts.

The film is applied to the front of the cardboard support, which will make the support waterproof and more resistant. Thus, the application is direct and it is no longer necessary to resume cardboard supports on another machine to place a transparent window on the cardboard support having cutouts.

 In addition, the laminator will not leave any marks on the laminated cardboard support so that the final product obtained is uniform and pleasant.

 The gluing machine will be particularly suitable for implementing a particular gluing process in which the glue has very fast drying properties after its application on the cardboard support so that the various impurities present in the workshop manufacturing can not adhere to the film at the transparent window and thus make it opaque.

 The laminating machine will have a construction geometry such that the glued surface of the film at the window, never comes into contact with any part of the machine or external body before it dries. It has in fact been noted that the slightest contact of the surface of the glued film when the glue is not completely dry, with any surface such as the periphery of a deflection roller or the like leaves an imprint on the film. which hinders transparency.

 Thus, at the present time, when we try to apply a lamination on a cardboard support presenting cuts with the traditional laminating machines, we do not fail to obtain a final product which presents traces at the level of the transparent window which come from the passage of the film between the pressure and back-pressure rollers which apply the film to the cardboard support.

 However, the machine according to the present invention overcomes these drawbacks to obtain a high quality end product.

 The film machine intended in particular for applying a polypropylene or acetate film on a cardboard support having cutouts, comprises a reel in which the film is stored in a roll, a station for gluing the surface of the film, a tunnel oven in which the glued film is heated, an applicator group composed of a pressure cylinder and a back pressure cylinder applied tangentially against each other between which the glued film superimposed on the front of the support passes cardboard, is characterized by the fact that means deflect the film-coated cardboard support assembly, at the outlet of the applicator group, to move it away from the back-pressure cylinder.

 The invention will be better understood if reference is made to the description below and to the accompanying drawings which form an integral part thereof.

 Figure 1 schematically shows an overall view of the laminating machine produced according to a preferred costilrction mode.

 Figure 2 shows, in detail, the operation of the gluing station.

 Figure 3 shows, in detail, the operation of the applicator group provided with deflection means according to the invention.

 The laminating machine of the invention is shown in Figure 1 in a preferred embodiment.

 It is a machine having a longitudinal arrangement necessary for successively carrying out the various operations necessary for processing the film.

 In fact, according to the present invention, the laminating machine incorporates the characteristics of the front lamination of cardboard supports by adapting to the fact that these have cutouts.

 The advantages of filming the outer face of the cardboard support are thus maintained, namely greater solidity, a shiny appearance and possibly a waterproofing of the product when, for example, a polypropylene film is used. However, the machine is equipped to apply a film of a kind, such as acetate or polypropylene. And, given the final characteristics sought, it is obvious that the stem will advantageously be transparent.

 In order to reduce the length of the machine, it will have a provision for processing the film on two stages.

 According to the embodiment of the film-coating machine shown in FIG. 1, it integrates the different work stations necessary for applying the film to the cardboard support. The frame 1 of the machine comprises, at one end a reel 2 in which the film roll is stored 3. In general, the width of the film will be identical to the width of the cardboard support to be filmed.

It is possible to juxtapose several rollers in order to apply a film on cardboard supports arranged in parallel.

 The film from the reel 2 is introduced into a gluing station 4. It has in fact been chosen to glue the film rather than the cardboard support in order to save the consumption of glue, in fact, because of its porous composition, the cardboard supports absorb a large part of the glue deposited on their surfaces and therefore, it is necessary to use large quantities to obtain satisfactory results.

 Consequently, the gluing station 4 makes it possible to coat the surface of the film with a film of glue of constant thickness on its surface.

 FIG. 2 illustrates a preferred embodiment of the gluing station 4. This firstly comprises a longitudinal tray 5 filled with glue 6. This glue 6 has properties of adhesion which makes it suitable for the surfaces to be glued .

 The glue tank 5 will advantageously be of small capacity so that the glue 6 contained in this tank does not dry. The tray 5 will advantageously work at a constant level, that is to say that an adhesive supply device will fill the tray 5 as and when required so as to keep the volume of glue present in the tray 5 constant. .

 A glue roller 7 is placed transversely in the tray 5, with respect to the direction of travel of the strip 8 of film, dipped in its lower part in the glue bath 6 present in the tray 5.

 A roller 9 around which the film strip 8 is wound is tangentially disposed with the gluing roller 9 so that the surface of the strip 8 which comes into contact with the gluing roller; either coated with glue.

 In order to deposit an adhesive film of substantially constant thickness over the entire surface of the film strip 8, the gluing station 4 will be provided with an equalizing roller 10. This equalizing roller will be disposed tangentially to the adhesive roller 7 and may adjust the spacing between the two rollers 7 and 10 so as to obtain a thickness of the adhesive film present on the periphery of the glue roller 7 adjusted as required. This adhesive film placed on the periphery of the adhesive roller 7 will then be deposited by capillary action on the strip of film 8 during its tangential contact with the adhesive roller 7.

 The adhesive used will advantageously be of a type containing heat-adhesive products and a hardener, in addition, it will have good transparency in the dry state.

 The film strip 8 glued from the gluing station 4 will then be introduced into a tunnel oven 11 has on the upper floor of the machine 1. This tunnel oven is of the conventional type and has, in its lower part, a series of rollers motor on which rests the strip of glued film which is thus driven. The upper part or tunnel oven is made up of an electric heating resistance which thus raises the temperature of the film and above all the preventive adhesive film on its upper surface.

 At the outlet of the tunnel oven 11, the glued strip of film 12 passes into the applicator group 13. Upstream of this applicator group 13, there is the cardboard media store 14, which makes it possible to route them one after the other. others, by placing them successively on a belt conveyor 15.

 Thus, the applicator group 13. is supplied on the one hand with glued film 12 and with cardboard support which, according to the present invention, has internal cutouts.

 A conventional suction device 16 will be available in the lower part of the belt conveyor 15 in order to press the cardboard supports on the conveyor belt and thus avoid any relative sliding of one cardboard support with respect to the other. It is in fact preferable to arrange the cardboard supports contiguously one after the other since the film tape is applied continuously and thus there is no loss of film.

 The applicator group 13 is illustrated in detail in FIG. 3.

It is composted in particular by a pressure cylinder 17 disposed transversely to the direction of travel of the cardboard supports 14 of the film tape 12. A back pressure cylinder 18 is disposed tangentially to the pressure cylinder 17. The film strip glued 12 as well as the cardboard supports 14 are introduced between the pressure 17 and backpressure cylinders 18 in order to apply the glued film 12 on the front of the cardboard supports 14.

 A hydraulic cylinder will strongly apply the back pressure cylinder 18 to the pressure cylinder 17 in order to press the film on the cardboard support. On the other hand, when the machine is not in use, the jack will be actuated so as to separate the cylinders 17 and 18.

 The cylinder 17 will be a rigid cylinder which will advantageously be surface chrome and heating. The back-pressure cylinder 18 will have a slightly flexible periphery, for example of the rubberized type in order to be able to admit possible unevennesses because of the thicknesses of cardboard supports.

However, and unlike conventional laminating machines, the flexibility of the rubberized surface of the counterpressor cylinder 18 must be very weakly compressible because it is essential that at the level of the cardboard cutouts, the peripheral surface of the cylinder back pressure 18 does not come into contact with the glued film, especially since it is the glued surface which immediately
would feel the fingerprints due to contact.

The bonding of the film on the cardboard support is almost
immediate and moreover, the hardener present in the adhesive cures
this so that it will lose its adhesion properties which
promote the bonding of impurities present in one atmosphere of the manufacturing workshop.

 At the outlet of the applicator group 13, the cardboard peliculated support is driven by a belt conveyor 19 arranged longitudinally on the machine 1 on the lower floor.

 The film-coated product can thus be recovered at the outlet of the machine, which can, for example, be equipped with a cutting device in order to separate the various film-coated cardboard supports linked together by the glued film strip.

 However, it has been noted that, if we content ourselves with eliminating the operations described above, the final product is not satisfactory since the windows made in the laminated cardboard supports show traces. However, it has been observed that by deflecting the strip 21 of film-coated cardboard supports at the outlet from the applicator group 13, so as to move the latter away from the counterpressure cylinder 18, good results have been obtained as regards the final product.

 The reasons for the phenomenon cannot yet be clearly explained, but it has been noted that by using different means to deflect the assembly of film-coated cardboard supports at the outlet of the applicator group 13 so as to separate this assembly from the backpressure cylinder 18, good results.

 Figures 1 and 3 schematize the relatively simple means yes have been used to obtain this deviation, it is however obvious that these means are not unique and that many equivalent means could be envisaged without departing from the scope of the present invention.

The means used cause a partial winding of all the cardboard laminated supports around the pressure cylinder
17, after the point of tangency between this pressure cylinder and the cy
back pressure liner 18.

 The means envisaged in FIGS. 1 and 3 are presented under the form of a deflection roller 21 which then has the working plane, 22 with the two cylinders 17 and 18, on the side of the pressure cylinder 17. The assembly of laminated cardboard supports 23 partially wraps around the deflection roller 21, then, by gravity, returns to settle on the belt conveyor 19 to be evacuated towards the outlet 20 of the machine 1.

 Good results have been recorded by applying glue to the film at a rate of 20 to 24 g / m 2, this glue being of the type with heat-bonding components and incorporated hardener. This is for a polypropylene film 12 to 20 microns thick or an acetate film 14 to 17 microns thick.

 In the case of a cardboard support width of approximately 0.5 m, the force applied by the hydraulic cylinder to the back-pressure cylinder 18 to press it onto the pressure cylinder 17 is between 1.5 and 2 tonnes.

 As emerges from the preceding description, the means described for deflecting the film-coated cardboard support strip at the outlet from the applicator group may be in different equivalent forms which cannot be described in the context of this description, however, it is quite obvious that the invention relates to the whole of the known means and with the range of the Man of the Art which would be suscepo bles to cause this deviation.

Claims (8)

 1. Laminating machine intended in particular for applying a film (8) of polypropylene or acetate on a cardboard support (14) pre, feeling cutouts, comprises a reel (2) in which the film (8) is stored in roller (2), a gluing station (4) of the surface of the film (8), a tunnel oven (11) in which the glued film (8) is heated, an applicator group (13) composed of a pressure cylinder (17) and a counter-pressure cylinder (18) applied one against the other between which the glued film (12) superimposed on the front of the cardboard supports (14) passes, characterized by the fact that means deflect the entire film-coated cardboard support (23) at the outlet from the applicator group (13) in order to move it away from the back-pressure cylinder (18).  2. Laminating machine according to claim 1, characterized in that the means ensure a partial winding of the laminated cardboard support assembly (23) around the pressure cylinder (17) after the point of tangency between the pressure cylinders ( 17) and nnt rn (8>.  3. Laminating machine according to claim 2, characterized in that the means are in the form of a deflection roller (21) disposed outside the tangent plane (22) to the two cylinders (17) and (18) , on the side of the pressure cylinder (17) around which the entire film support (23) passes.  4. Laminating machine according to claim 1, characterized in that the pressure cylinder (17) is chrome-plated and heated.  5. Laminating machine according to claim 1, characterized in that the back-pressure cylinder (18) has a flexible surface on its periphery, however, very slightly compressible.  6. Laminating machine according to claim 1, characterized in that the back-pressure cylinder (18) is applied to the pressure cylinder (17) with a force between 1.5 and 2 tonnes for a support width cardboard (14) of about 0.5 m.  7. Laminating machine according to claim 1, characterized in that the adhesive (6) comprises heat-adhesive components and an incorporated hardener.  8. Laminating machine according to claim 7 characterized in that the adhesive is applied to the film (8l at a rate of 20 to 24 g / m2.