FR2883223A1 - METHOD FOR MANUFACTURING A BI-COMPONENT TRAY, AND INSTALLATION FOR CARRYING OUT SAID METHOD - Google Patents

Abstract

The subject of the present invention is a method of manufacturing a container constituted by an outer casing (1), made for example of cardboard, internally lined with a sealed plastic film (15) thermoformed directly into said outer casing (1). in volume ; said plastic film (15) is secured to said envelope (1) by a gluing operation during which the inner surface (4) of said outer envelope (1) is glued on one or more areas (9) to constitute the or the areas of assembly between the two materials (1, 15) constituting said tray.Selon the invention, the gluing operation consists in applying the adhesive on the inner face (4) of said outer casing (1) by at least one buffering operation, so as to deposit the glue (8) by contact. Advantageously, the adhesive is applied to at least one strip-like zone (9) extending over at least a portion of the length of the side wall belt (3) of the envelope (1), near its upper border (10).

Description

The present invention relates to a method of manufacturing a container

  recyclable seal consisting of the assembly of an outer casing, made of a relatively rigid packaging material such as for example cardboard, and an inner lining made by means of a thermoformed plastic film which ensures

  the tightness of the tray. The invention also relates to the installation for implementing such a tray manufacturing method.

  In the processes for manufacturing bicomponent trays known to date, the outer casing is generally assembled with the plastic film by means of a sizing operation, the adhesive being applied by spraying or spraying on the inner face of said envelope. Such a method is for example described in the document FR-2 826 937.

  However, some glues of interest for the assembly of trays whose contents are subsequently intended to be heated or heated, are difficult to apply by spraying; for example, problems are known for spraying certain acrylic-type glues.

  In addition, glue spraying is not always a clean and efficient application method. This causes in fact generally environmental soils, which can be detrimental to an industrial production trays, especially in the food field.

  To overcome these drawbacks, the applicants have developed a method of manufacturing a two-component tray allowing a rapid and targeted application of the adhesive on one or certain zones of the external envelope, without risk of environmental contamination. with this glue.

  The method according to the invention is particular in that the sizing operation consists of applying the adhesive to the inner face of the outer envelope by at least one buffering operation, so as to deposit the adhesive by contact.

  In the case of the manufacture of a tray whose outer envelope and the thermoformed plastic film each comprise a bottom wall associated with a sidewall belt, the sizing operation advantageously consists in applying the adhesive by buffering on a at least part of the inner face of the sidewall belt of said outer shell.

  According to a particular embodiment of this method, the sizing operation consists in applying the adhesive to a strip-like zone extending over at least a part of the length of the side wall belt. In particular, the adhesive strip is applied at the upper edge of the side wall belt, and preferably near the upper edge of this wall belt, so as to preserve a small peripheral space between said strip of glue and said upper border.

  The present invention also relates to the installation for implementing this method of manufacturing two-component trays.

  The installation in question comprises at least one sizing member of the buffer type - capable of being loaded with adhesive on at least a portion of its surface, and - able to come into contact with the zone or zones to be glued on the envelope External volume, for the removal of glue.

  According to a particular characteristic of the invention, the corresponding installation comprises means for the glue loading of the sizing member, these loading means being shaped to deposit the glue on the surface of said sizing member which is intended to to come into contact with the area or areas to be glued to the outer envelope. These glue loading means advantageously comprise a planar surface for supplying glue.

  In this context, the glue loading means advantageously comprise means for depositing the glue on an intermediate support medium, the gluing member coming to glue on said intermediate support.

  According to another particular characteristic of the invention, the sizing member consists of a body made of an elastic material; this member is able to be deformed between - an adhesive pick-up conformation, in which the surface or surfaces to be loaded with adhesive project in a same plane, and - a sizing conformation, in which the one or more surfaces loaded with glue are able to come into contact with the area or areas to be glued to the outer envelope.

  This particular sizing member is advantageously provided with at least one protruding elastic portion, preferably in the general shape of a dome, which is intended to be compressed when said sizing member is positioned within the outer envelope of the package during the sizing operation, this to optimize the ejection of said outer envelope with respect to said sizing member during the extraction of the latter.

  The invention will be further detailed, without being limited by the following description and the accompanying drawings in which: - Figure 1 shows, in general and schematic, the main steps of the method according to the invention; - Figure 2 shows, also schematically, the main steps for the glue loading of a particular buffer-shaped sizing member fitted to a two-component trays manufacturing facility.

  The main steps of the process for manufacturing a tray according to the invention are shown in FIG.

  Step A presents the outer casing 1 of the tray. This outer casing 1 is made of suitable material, preferably cardboard (compact or corrugated, preferably recyclable cardboard type). It is composed in this case of a bottom wall 2 associated with a belt of peripheral side walls 3 slightly flared outwardly to form a frustoconical assembly.

  This casing 1 is made by placing in volume a cardboard blank suitably cut and grooved; it can also be obtained by molding a paper pulp, for example.

  Alternatively, the outer casing 1 can be made of a cellular plastic material; it can also be achieved by the combination of different materials, for example a mixed cardboard / wood unrolled.

  In practice, the nature and the thickness of the material of the outer casing 1 are chosen according to the dimensions of the tray and according to its destination.

  Steps B, C and D detail the sizing operation of the outer casing 1 for the purpose of assembling the thermoplastic film. In general, this sizing operation consists of an application of adhesive on one or more areas of the inner face 4 of the outer casing 1 by at least one buffering operation, so as to deposit the adhesive by contact.

  In FIGS. B, C and D in question, a sizing member in the form of a buffer 5 ensures the removal of the adhesive on the zone or zones to be bonded to the outer envelope 1 by contact with its inner face 4.

  Here, the area to be glued advantageously corresponds to a peripheral strip situated at the level of the upper part of the internal face of the wall belt 3.

  For this, in step B, the gluing member 5 is previously loaded with glue 8 on the portions of its peripheral surface designed to fit the zone or zones to be glued to the outer envelope 1. The glue loading the sizing member 5 is made by any suitable means; a possible embodiment of these glue loading means are described hereinafter with reference to FIG. 2.

  In this case, the sizing member 5 has a trapezoidal section, the dimensions of which correspond, with the game, to those of the inner face 4 of the outer casing 1; it is mainly composed of a bottom surface 6 associated with a belt of side surfaces 7. The gluing member 5 is loaded with glue 8 on its lateral surfaces 7; the adhesive 8 is here distributed in a strip extending over the entire length of the lateral surfaces 7, on the side of their edge opposite the bottom surface 6.

  In step C, the gluing member 5 is positioned within the outer casing 1 so that its peripheral surfaces 6 and 7 come into contact with the inner face 4 of the casing 1. The glue 8 loaded on the surface of the sizing member 5 is then deposited by contact on the adjacent areas to be glued on the envelope 1.

  Once the glue has been properly deposited, the gluing member 5 is extracted from the envelope 1 (step D). In this case, the glued zone 9 of the envelope 1 is located on the peripheral walls 3, on the side of their upper free end 10. As indicated above, this glue zone 9 is advantageously in the form of a web. extending along the length of the inner face 4 of the peripheral wall belt 3. The corresponding band may be continuous or discontinuous; it can in particular be interrupted at the corners of the wall belt 3. The adhesive strip 9 is located a few millimeters from the upper edge 10 of the casing 1; thus preserving a space between the glue 8 and said upper edge 10, which avoids any overflow of the glue on the upper edge of the envelope or to the outside.

  Furthermore, the extraction of the sizing member 5 can be optimized by the use of a separation system arranged on its bottom surface 6; this separation system (not shown in Figure 1) may for example consist of a spring or a rubber block which is compressed against the bottom wall 2, during the gluing of the outer casing. The sizing member 5 may also be equipped with a compressed air type system, adapted to push the outer casing 1 during its extraction. Likewise, there may be provided means for holding the outer casing, for example depression means causing suction on the bottom wall 2.

  The outer envelope 1 glued is then able to receive the thermoplastic film reported internally. Steps E and F of FIG. 1 correspond to placing the plastic film 15 in volume, directly in the casing 1, by a thermoforming technique. For this, the plastic film 15 is for example implemented by means of a thermoforming matrix 16 common in the field concerned, or by any other conventional technique. It will be noted that for all the steps A to F, the outer envelope 1 is previously arranged in a suitable matrix not shown.

  Step F shows the finished product, that is to say the tray consisting of its outer casing 1 lined internally with a thermoformed plastic film 15; these two materials are joined together by the bonding zone 9.

  In this case, the gluing zone 9 in the form of an adhesive strip formed at the level of the free upper edge 10 allows the thermoplastic film 15 to be properly held within the outer casing 1; the particular arrangement of this bonding zone 9 makes it possible to prevent possible wrinkling phenomena of the thermoplastic film 15, which may occur in particular because of its shrinkage during its cooling within the envelope 1. Moreover, the two components 1 and 15 of the tray can very easily be detached, especially after use, for recycling materials.

  Of course, the zone or zones to be glued to the outer envelope may also be in any other form (point (s) ...); we can also consider a gluing of all or part of the bottom wall 2.

  The buffing gluing operation makes it possible to apply the glue in a single operation, in a precise and rapid manner on one or more zones of the outer envelope, and in particular on the peripheral side walls, in the form of a band of glue.

  In general, this manufacturing method allows the gluing of the outer casing of the tray with many types of glue, normally difficult to apply by spraying; this is the case, for example, for acrylic glues. The assembly by such an acrylic glue is particularly interesting for its heat resistance characteristics, which makes it possible in particular, in the context of an application of the tray in the food industry, to provide heating / reheating of food directly in their packaging tray.

  Still generally, it will be noted that a two-component tray, the thermoformed film of which is assembled with the outer envelope by means of an adhesive strip extending just below the upper edge of said outer envelope, could be obtained by any other suitable manufacturing process. This tray could for example also be obtained using a technique of projection and / or glue spraying. One would then meet a risk of projection of glue in the ambient environment; however, the characteristics of the tray thus obtained would be preserved, especially in terms of the positioning quality of the thermoformed film.

  Figure 2 shows a particular sizing member that can be used in the manufacturing process of Figure 1; this figure 2 again shows the main steps for the glue loading of this sizing member.

  FIG. 2A shows the buffer-shaped sizing member 5. This sizing member is made of a suitable material, in this case a deformable elastic material, of the silicone type.

  The dimensions and the external shape of this sizing member 5 are adapted as a function of those of the internal face of the outer envelope of the tray to be glued. In general, the external dimensions of the sizing member 5 correspond, with the game, to those of the inner face of this envelope.

  The sizing member 5, shown in Figure 2, mainly comprises a bottom surface 20, generally projecting dome, associated with side surfaces 21; it is provided, in addition, an internal recess 22, shaped to allow its deformation as detailed below.

  In general, this sizing member 5 is intended to be associated with operating means (not shown) within a complete installation adapted to implement the method described above in relation to FIG. 1.

  Steps B to E of Figure 2 show the main steps for the glue loading of the buffer member 5 in question.

  First, in step B, the sizing member 5 is deformed so that the parts 23 of its peripheral surface intended to be loaded with adhesive are brought into projecting and that in the same plane. In this case, the projecting portion 23 of the sizing member 5 corresponds at least substantially to a peripheral band of the lateral surface 21.

  To obtain this deformation, the internal recess 22 is here subjected to a depression adapted to cause the rise of the bottom surface 20, and the projection of the portion 23 of its lateral surface 21. Of course, this deformation could be obtained by any appropriate means, for example by mechanical traction means.

  Step C represents the deformed sizing member 5 and a flat intermediate support 25 on which said sizing member 5 will feed glue.

  For this purpose, this intermediate support 25 is itself previously glued by suitable deposition means, not shown; as an indication, these removal means could consist of a cliché-type device, usually used in the general field of printing.

  In this case, the adhesive 26 is deposited in a strip corresponding to the conformation of the projecting portion 23 of the sizing member 5.

  In general, and alternatively, the sizing member could also come to feed glue in an open receptacle containing glue in the form of a flat surface.

  Thus, in steps D and E, the gluing member 5 is moved in a vertical back / forth movement towards the intermediate support 25, so that its projecting portion 23 comes into contact with the glue 26 of the intermediate support. 25; the projecting parts 23 are then suitably loaded with glue 26, as represented diagrammatically in step E. The gluing element 5 loaded with glue can then return to conformation suitable for the desired gluing, as shown in FIG. step F. For this, the depression applied at the internal recess 22 is stopped; the elastic deformation capacity of the sizing member 5 allows its automatic return to its sizing conformation.

  In the state, the sizing member 5 is glued on a part of its lateral surface 21, this adhesive 26 extending in the form of a strip or peripheral strip.

  The gluing member 5 thus loaded with glue can be used as presented previously in the description above in relation to FIG.

  During this implementation, it will be noted that the bottom surface 20 of the sizing member 5, generally domed, is intended to be driven by the bottom wall 2 of the outer casing 1, when the sizing operation of this envelope. As explained above, this structural feature is intended to facilitate the ejection of the sizing member when it moves away from the outer envelope, following its sizing.

  The sizing member 5 as described above in relation with FIG. 2 is particularly interesting because it can be loaded in a single step, once deformed in the sampling conformation, on different parts of its surface. , said parts constituting different faces of the sizing member in sizing conformation. Similarly, this member allows, in a single operation, the gluing of different walls of the outer casing which are not in the same plane, this accurately and efficiently.

  Thus, the sizing member suitably loaded with glue can for example allow glue removal, in a single operation, on an area having a general shape of strip or strip extending substantially over at least a portion of the length of the strip. the inner face of the side wall belt of the outer casing 1 of the tray, this advantageously at the upper edge of its walls. In general, the corresponding adhesive strip may be continuous or discontinuous; the gluing may also consist of a plurality of glue points.

  Other glue loading techniques of the buffer 5 can also be envisaged; for example, this loading could be made from an internal power supply, by crossing the surface 21 adapted for this purpose.

Claims (12)

- CLAIMS -   1.- A method of manufacturing a tray consisting of an outer casing (1), made for example of cardboard, lined internally with a sealed plastic film (15) directly thermoformed in said outer casing (1) by volume, said plastic film (15) being secured to said envelope (1), by a sizing operation during which the inner surface (4) of said outer envelope (1) is glued on one or more areas (9) to form the or the zones of assembly between the two materials (1, 15) constituting said tray, characterized in that the sizing operation consists in applying the adhesive to the inner face (4) of said outer casing (1) by at least one buffering operation, so as to deposit the glue (8, 26) by contact.   2. A method according to claim 1 for the manufacture of a tray whose outer casing (1) comprises a bottom wall (2) associated with a side wall belt (3), characterized in that the operation of Sizing consists in applying the adhesive by stamping on at least part of the internal face (4) of the side wall belt (3).   3. A method according to claim 2, characterized in that the sizing operation is to apply the adhesive by stamping on a zone (9) shaped strip extending over at least a part of the length of the belt side walls (3).   4. A process according to claim 3, characterized in that the adhesive strip (8) is applied at the upper edge (10) of the side wall belt (3).   5. A method according to claim 4, characterized in that the adhesive strip (8) is applied near the upper edge (10) of the side wall belt (3), this to preserve a space between said strip of glue (8) and said upper border (10).   6. Installation for carrying out a method of manufacturing a tray according to any one of claims 1 to 5, which installation comprises at least one sizing member (5) of the type of buffer capable of being loaded. in glue (8, 26) on at least a part of its surface (7, 21) and - able to come into contact with the zone or zones to be glued (9) of the outer envelope (1) of said container, for removing the glue (8, 26).   7.- Installation according to claim 6, characterized in that it comprises means for the glue loading of the sizing member (5), said loading means being shaped to deposit the glue (8, 26) on the surface portion of said sizing member (5) which is intended to come into contact with the zone or zones (9) to be glued to the outer envelope (1).   8.- Installation according to claim 7, characterized in that the glue loading means comprises a planar glue supply surface (8, 26).   9.- Installation according to any one of claims 7 or 8, characterized in that the glue loading means comprises means for depositing the adhesive on an intermediate support medium (25), the sizing member (5) being charged in glue (8, 26) on said intermediate support (25).   10.- Installation according to any one of claims 6 to 9, characterized in that the sizing member (5) consists of a body made of an elastic material, able to be deformed between - a conformation of glue removal in which the surface or surfaces (23) to be loaded with adhesive project in a same plane, and - a sizing conformation in which the surface or surfaces (23) loaded with adhesive are able to come into contact with the zone or zones (9) to be glued to the outer envelope (1).   11.- Installation according to claim 10, characterized in that the sizing member (5) is provided with at least one resilient portion (20), projecting, which is intended to be compressed when said member sizing (5) is positioned within the outer casing (1) during the sizing operation, to optimize the ejection of said outer casing (1) with respect to said sizing member (5) during the extraction of the latter.   12.- Installation according to claim 11, characterized in that the sizing member (5) is provided with an elastic portion (20) at its surface intended to come into contact with the bottom wall (2). the outer shell (1), said resilient portion (20) having a generally domed shape.