FR2583385A1 - COMPOSITE MATERIAL BOX - Google Patents

Abstract

IN A MIXED BOX OF COMPOSITE MATERIAL, THE BODY 1 CONSISTS OF AT LEAST ONE OUTER CARTON LAYER 5, A METAL STOP SHEET 6 INTERNALLY COVERING IT AND AN INTERNAL SEALABLE PLASTIC MATERIAL COVER 7, THE CLOSURE OF ' A LAYER 13 WITH A COATING OF SEALABLE PLASTIC MATERIAL 14 AND THE EMBEDDED BOTTOM 2, TO BE PLACED AFTER FILLING, AT LEAST ONE LAYER OF CARDBOARD 9, A METAL STOP SHEET PLACED ON ITS INTERNAL FACE AND A COATING OF SEALABLE PLASTIC MATERIAL 11 ARRANGED INTERNALLY, THE BOTTOM BEING SEALED TO THE BODY BY HIGH FREQUENCY INDUCTIVE.

Description

Mixed box in composite material.

  The invention relates to a box made of composite material, the body of which consists of an outer cardboard layer, a barrier sheet for example of aluminum covering the latter internally and an inner coating of sealable plastic, the closure of which is formed of a layer, if necessary tearable, provided with an internal coating of sealable plastic material, and the stamped bottom of which, put in place after introduction of the content, is composed of at least one layer of cardboard, metallic barrier sheet and a sealable pastic coating

  arranged internally, the bottom edge being re-

  lifted over the extreme edge of the body and sealed

  to the body on the internal and external faces.

  The mixed boxes of the above type have become of considerable importance, in particular for the packaging of food products, since they are more economical than those known. The tightness to liquids and gases, as well as to the diffusion of water vapor, of such mixed boxes is obtained in the first place by the metallic stop sheets as a rule, but causes particular difficulties in the region. connection points of the closure and the bottom with the body. This tightness is obtained by sealing by means of coatings

  of plastic. It is known in the practice of intro-

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  simply fill the pressed bottom of cardboard composite flush with the body. This has the disadvantage that the edge of the body is exposed, so that moisture can enter the cardboard composite of the body and cause it to swell. Instead, it has already been proposed to recover the edge of the body by stopping the edge of the stamped bottom flush with the external lateral surface of the body. However, the bottom must then have extremely precise dimensions so that the edge does not exceed

  not outward and thus does not lift easily.

  This dimensional accuracy generally cannot

  be held because the body is not absolutely circular.

  This is even more critical for non-circular boxes, of rectangular cross section for example with rounded corners. Finally, it has already been proposed to make the body a little longer than necessary and to fold it over the deep-drawn bottom introduced inside. This process requires the use of significant material, is expensive and leads to large wall thicknesses and in particular for non-circular boxes with an unsightly appearance, in particular to the formation of folds. This formation of folds is in particular practically inevitable for non-circular boxes. For this reason, this

  method of fixing the bottom is here excluded.

  All of the above attempts have therefore failed

  could lead to no entirely satisfactory solution.

  This is the reason why in practice, to this day, the bottom is always constituted by stamped tinplate and is folded down on the body after introduction

content.

  In the known mixed box mentioned above (US Pat. No. 3,434,651), the tinplate bottom is, it is true, replaced by a bottom made of cardboard composite, but this configuration requires a heat seal from the bottom to the body. Due to the necessary heat transfer, which takes some time, until the coating

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  of plastic material reaches its melting temperature, such a mixed box cannot however compete with known boxes with a tinplate bottom,

  because the machine cycle times are too long.

  In other words, the economic advantage of the cardboard composite background compared to a tinplate background is practically nullified by the time necessary to

the closure.

  The same observation applies to another form of realization.

  known invention (patent DE 1,163,130) in which is first introduced into the body of the container an aluminum shaped part coated with plastic material with folded edge

  down and then we put in place a component

  cardboard site provided with a plastic coating whose edge is deformed on the external side over the lateral surface of the body. Here again, a heat seal takes place between the aluminum closure part and the internal face of the edge of the container as well as between its external face and the internal face of the edge of the cardboard composite part. The heat being brought in this case exclusively from the outside, the cycle times

  for closing the container are excessively long.

  Two-part production and two-part installation

  Closing stages are also disadvantageous.

  The object of the invention is to replace the known tinplate base of a mixed box with a more economical base and having the same visual effect, while retaining the

  same durations of closing cycles.

  From the mixed box defined in the introduction, this object is achieved in that the metal stop sheet at the bottom is arranged on the internal face of the cardboard sheet and in turn has on its internal face the coating of plastic material. and the bottom is sealed

  to the body by high inductive frequency.

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  Thanks to the use of the high frequency inductive process, one arrives at practically the same cycle times as for the folding down of known tinplates, since a transfer of heat through the different layers of the bottom and of the body has not to happen. The arrangement according to the invention has the additional advantage that the installation of the bottom can be carried out practically with installations similar to those used for tinplate backgrounds. Sealing by high frequency on the inner and outer faces of the bottom is possible mainly because the metallic barrier sheet is inside, i.e. as close as possible

  sealable plastic coating.

  The method according to the invention has the very particular advantage of being able to be applied not only for circular boxes but also for non-circular boxes with the same advantages and also to a large extent independently of the wall thickness.

from the body.

  According to an exemplary embodiment of the invention, the bottom cardboard layer can carry on its external face a metallic color impression for example and a protective lacquer, on the one hand to give the bottom a metallic appearance, on the other hand to prevent, thanks to the protective lacquer, penetration of moisture into the layer

of cardboard.

  According to an advantageous embodiment, the raised outer edge of the bottom is folded inward in the direction of the edge, so that the cutting surface is not exposed and is thus also protected against access - from humidity. It also avoids delamination of the

  composite material at the cutting surface.

  Finally, provision can be made according to the invention for the closure opposite the bottom to have the same structure as the latter and

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  is sealed to the body in the same way as the bottom, and that the closure is further provided with a breaking line at least in the region of the cardboard layer, which forms the outline of a shutter which can be closed. This embodiment has the advantage that the bottom and the closing cover are made of the same material and with the same cutting tools and can also be linked to the body with the same closing machines. This embodiment is preferably used for flowable products, which are removed from the mixed box in portions, the box can be each time

closed by means of the flap.

  The invention will be better understood thanks to the description

  given below of some exemplary embodiments and the accompanying drawings in which: - Figure 1 is a partial sectional view of an embodiment of box according to the invention; - Figure 2 is a section in the region of the connection between bottom and body in another embodiment; - Figure 3 is a section in the region of the connection between closure and body; and - Figure 4 is a partial top view of the form

according to FIG. 3.

  The mixed box shown in the drawings includes a

  body 1, bottom 2, closure 3 and in the realization

  tion according to Figure 1 a snap-on cover 4 consisting

  by a plastic part.

  The body 1, which can have any cross section (circular or not), is composed of at least one layer of cardboard 5, a stop sheet 6 disposed

  on the inner side, for example aluminum, and a coating

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  Tement 7 disposed on the inner face of the latter, in sealable plastic. The body 1 is brought in closed form by spiral or long winding from the above composite material. The sealability on the external face of the body is obtained by a lacquer

or an appropriate coating.

  The bottom 2 has in principle the same structure as the body 1. It is composed of at least one layer of cardboard 9 lined internally with a metallic barrier sheet, for example aluminum, which, in turn, carries a

  coating 11 of a sealable plastic. Advantageous-

  The cardboard sheet 9 has a metallic color printing on its outer face 12. The bottom 2 is stamped from the composite material described so

  to be able to be inserted into the body 1.

  In the embodiment according to FIG. 1, the closure

  3 is produced in the form of a closing diaphragm.

  It is composed of an external metal sheet 13 and an internal coating 14, which is also formed of a sealable plastic. In addition, a tear-off tab 15 is placed on the external face for the opening. The closing diaphragm 3 is also pressed and inserted into the body 1. The snap-on cover

  4 is used to close the container after the first opening.

  The edge 16 of the closing diaphragm 3 is pulled outwards on the open end face 17 of the body 1 and the plastic covering 14 and the covering 7 of the body are fixed by heat sealing or by high frequency. The container is delivered in this form to the filling workshop, where the product is introduced therein after which the container is closed by the bottom 2. For this purpose, the edge 18 of the stamped bottom 2 introduced into the body is deformed on the open end 19 of the body

  1 and applied to the external lateral surface of the body 1.

  Next, the coverings 7 of the body are sealed and the coating

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  tement 11 of the bottom 2 by high frequency inductive, which also leads in the region of the bottom to a hermetic closure, gas and liquid tight and diffusion

steam.

  In the exemplary embodiment according to FIG. 2, the raised edge 18 of the bottom 2 is somewhat crimped inward, so that its front cut surface 20 is pressed

  against the external face of the body 1 and is thus protected.

  If necessary, it is possible here to slightly compress the entire edge of the bottom 2 covering the edge 19 of the body, thus

  than the body itself in the slice region.

  FIG. 3 shows an upper closure 2 composed, like the bottom 2 of FIG. 1, of a layer of cardboard 21, of an internal metallic stop sheet 22, of a coating of plastic material 23 and of a protective outer lacquer 24. The closure 2 covers by its edge the upper edge 26 of the body 1 and is linked to the latter in a sealed manner by high frequency sealing of the

  plastic coatings 7 and 23.

  Figure 4 shows a top view on a smaller scale of the closure 3 according to Figure 3. In this form

  the joint box has a cross-section

  dirty rectangular with rounded angles 27. In the region of an angle 27, the closure is provided with a breaking line 28 of triangular shape, which, as also shown in Figure 3, is located inside the edge of the closure covering the body. The closure 3 can be broken along this rupture line 28, which gives rise to a sort of flap 29 which can be closed after the first opening. The opening thus formed can serve

  opening, especially when it is available

located in the corner.

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Claims (4)

Claims.   1. Box of composite material, the body of which consists of an outer cardboard layer, of a foil, for example of aluminum, covering it internally and of an inner coating of sealable plastic, the closure of which is made up of a layer, if necessary tearable, provided with an internal coating of sealable plastic material and the deep-drawn bottom of which, put in place after introduction of the content, is composed of at least one layer of cardboard, a stop sheet metallic and a coating of sealable plastic arranged internally, the bottom being raised by its edge over the extreme edge of the body and sealed to the body on the internal and external faces, characterized in that the metallic stop sheet (10) of the bottom (2) is arranged on the internal face of the cardboard sheet (9) and in turn has on its internal face the plastic coating (11)   and that the bottom (2) is sealed to the body (1) by high frequency this inductive.   2. Mixed box according to claim 1, characterized in that the cardboard layer (9) of the bottom (2) carries on its outer face an impression of metallic color   (12) for example and a protective lacquer.   3. Mixed box according to one of claims 1 and 2,   characterized in that the raised outer edge (18) of the bottom (2) is compressed inward towards the body.   4. Mixed box according to one of claims 1 to 3, character-   laughing in that the closure (3) opposite the bottom is constituted   killed in the same way as the bottom (2) and sealed to the body (1) in the same way as the latter and that the closure (3) is provided, at least in the area of the cardboard layer, with a rupture line (28) which forms the outline of a shutter (29) which can be closed.