WO1993001983A2 - Heat-insulating package for the transport of food products - Google Patents

Abstract

The present invention relates to a heat-insulating package particularly adapted to the transport of food products already packaged in boxes, bottles or the like, characterized in that it is comprised of at least one central heat-insulating sleeve (1) around which is arranged a blind, concentric and slightly tight tube (2), having a height lower than that of said sleeve (1), the package comprising also a cap (4) slidingly mounted on the upper part (1a) of the sleeve (1) emerging from said tube (2) after the mounting thereof around said sleeve (1).

Description

 INSULATED PACKAGING FOR THE TRANSPORT OF FOODSTUFFS

FOOD

The present invention relates to an insulating packaging for transporting foodstuffs in particular.

The provisional packaging of certain common foodstuffs, such as bottles, ice cream, frozen foods or the like, for transport from the air-conditioned department of the store to the consumer's refrigerator, requires specific heat-insulated packaging intended to maintain for a few minutes or a few hours their temperature at a substantially constant level. A number of packages are known which more or less perfectly fulfill this function; in particular, there are improperly called "insulated" bags in which the foodstuffs to be preserved from being heated can be transported in bulk. However, these bags only provide very relative thermal insulation, in any case insufficient for transport exceeding ten minutes. Conversely, we have known for many years the so-called "thermos" devices (Trademark) which, if they are not strictly speaking packaging, allow to store for several hours liquids or the like at a given temperature; these thermos are however very expensive and prove in any case unsuitable for the transport of foodstuffs themselves packaged.

The present invention aims to remedy these disadvantages by proposing a heat-insulating packaging especially suitable for transporting food e ^~ 'tional already packaged in boxes, t ..teilles or the like, characterized in that it comprises at least one central insulating sleeve around which a concentric and slightly tightening blind tube is arranged, of a height less than that of said sleeve, said packaging also comprising a cap mounted to slide on the part of the sleeve emerging from said blind tube, after its mounting around said sleeve. It will first be observed that the packaging proposed by the present invention is very different from the packaging described in patent FR-1,388,978 in the name of the Company LINCRϋSTA. In fact, this latter patent describes a sealed package resistant to large and sudden temperature variations, characterized in that it comprises a tube made of a plastic material resistant to low temperatures, at least one of the ends of which is closed by a sliding plug provided with a seal, the other end being closed by a fixed or sliding plug; said plastic tube is housed in an outer cardboard tube with crimped bottoms, comprising a sealing layer of aluminum or cardboard impregnated with pitch, and an inner cardboard tube is also slipped inside said plastic tube. In this way, the outer and inner cardboard tubes protect said plastic tube from the risk of cracking.

The aim sought by this latter patent is thus to obtain a perfectly sealed tubular packaging, capable of withstanding variations in volume due to high temperature gradients (-40 ° C to + 70 ° C). In this sense, although the general arrangement of this anterior packaging seems to reproduce the combination which is the subject of the present invention, it is obvious that the function of the plastic tube, for example of phenolic laminate, which provides sealing packaging LINCRTJSTA is not heat insulating; it is therefore entirely original and new to use a heat-insulating tube in the manner of the invention. In this regard, the heat-insulated packaging of products to be temporarily protected from reheating would not be at all correctly ensured by LINCRUSTA packaging. The latter is also very specifically intended for the storage or transport of products or goods to be preserved from any penetration of moisture, which is not the objective pursued by the present invention. In a preferred variant of the invention, the heat-insulated packaging thus formed is cylindrical, that is to say that the central sleeve, the lower tube and the cap, themselves cylindrical, are generated respectively by a rectilinear generator displaced in parallel to itself along a plane directing curve. In the most common case, the director will be taken circular, oval or polygonal, but other forms are not excluded. Furthermore, the central insulating sleeve can be produced in many ways. For example, it can be composed of a cardboard tube inside which is added, or laminated, at least one layer of foam, asbestos or the like. According to a particularly advantageous variant of the invention, the central cylindrical sleeve is formed by rolling, convolute or spiral, of at least one strip of cardboard and at least one strip of polyethylene foam.

In a first embodiment, the foam and cardboard tube produced comprises at least two layers of cardboard laminated one on the other, then at least one layer of polyethylene foam, then at least two other layers of cardboard laminated l one on the other, the innermost cardboard layers not being glued to said layer of foam. In this case, the foam is held by pinching between the layers of cardboard.

In a second embodiment, the foam and cardboard tube comprises at least two layers of cardboard laminated one on the other, then at least one layer of polyethylene foam, then at least two other layers of cardboard laminated one on top of the other, the innermost layers of cardboard being glued to said layer of foam. This bonding of the foam layer can also be done in two ways:

- either in a conventional manner using a vinyl adhesive or a hot-reactivated adhesive of the type holt-melt, identical to that which can be used for laminating the cardboard strips together.

- Or, unexpectedly for a person skilled in the ordinary art, by blowing hot air on the foam strip and on the face of the cardboard strips to be glued to it, the foam used then having to be a polyethylene foam crosslinked while the inside of the cardboard strips must have been prepared by gluing a paper / polyethylene complex. Thus, the hot air blown through nozzles, arranged just in front of the mandrel on which the tube is rolled, comes to cause at least superficial crosslinking of the strip of polyethylene foam on the one hand, and of the polyethylene layer cardboard / paper / polyethylene complex on the other hand; in this way, at the time of rolling which is normally carried out using an endless strip applying an adhesive pressure on the strips to be laminated, an autogenous welding takes place between the polyethylene foam and the cardboard strips. covered with the paper / polyethylene complex.

In the latter case, it is even possible to have lateral hot air nozzles intended to cause the crosslinking of the edges of the strip of polyethylene foam, which allows, for a spiral or convolute rolling with contiguous turns, to cause welding. autogenous turns of the foam strip by their edges. We therefore understand all the advantage that can be obtained from this latter technique on the sealing of the cardboard and foam tube thus manufactured. Other characteristics and advantages of the present invention will emerge more clearly from the description which follows of an embodiment of a heat-insulating packaging given by way of nonlimiting example with reference to the appended drawing in which: - Figure 1 is a section sagittal of said packaging, - Figure 2 is a schematic representation of the preferred rolling mode of the tube acting as an insulating inner sleeve.

The packaging shown in FIG. 1 first of all comprises a central heat-insulating cylindrical sleeve 1 enclosed in a blind cylindrical tube 2 acting as the bottom of the packaging. To this end, the tube 2, for example produced by rolling cardboard strips, is provided with a reinforced bottom 3 which is crimped at the lower end of said tube 2. The latter is, moreover, of a calculated internal diameter to allow it to be mounted by sliding around the sleeve 1; the tube 2 nevertheless slightly tightens the sleeve 1 and it is possible, moreover, to glue these two elements one against the other so as to secure them firmly.

Normally, the length of the sleeve 1 is fairly markedly greater than that of the tube 2, so that the upper part 1a of the sleeve 1 can be capped by means of a cylindrical cap 4 which could be similar in all respects to the tube. lower 2. This cap 4 thus comprises a bottom 5, possibly reinforced and crimped at its upper end. Furthermore, the cap 4 is not glued against the sleeve 1 but slides frictionally around the latter, so that one can open and close the packaging quite easily.

According to an additional characteristic of the packaging according to the invention, at least the bottom 5 of the cap 4 is provided with a wafer 6 of polyethylene foam, or of a similar insulating material, just engaging, at the closing the cap 4 on the upper part 1a, of the sleeve 1, in the neck of said sleeve 1; this wafer 6 has a small thickness which nevertheless suffices to isolate the packaging at the bottom 5. The same arrangement could of course be applied to the bottom 3 of the lower tube 2.

In a preferred embodiment of the invention, the sleeve 1 is, for its part, manufactured by cutting of a composite cardboard and foam tube which it is advantageous to manufacture by rolling with contiguous turns of cardboard strips alternating with at least one polyethylene foam strip. Rolling can be convolute or spiral, the choice between these two techniques being made according to the mechanical characteristics required for packaging.

A method of rolling tubes, more particularly developed for the manufacture of heat-insulating composite tubes intended for the manufacture of packaging according to the present invention, consists, according to FIG. 2, in using at least one strip of crosslinked polyethylene foam 7 laminated to at least one strip 8 of a cardboard / paper / polyethylene complex which is common to use as a microbial barrier in certain food packaging. According to the variant shown in FIG. 2, the composite tubes intended for the production of heat-insulating sleeves 1 are produced by spiraling with contiguous turns from seven superimposed strips 7 to 13 winding on a mandrel 14 in the following manner:

- a first internal strip 9 of a complex of paper, aluminum and sliding lacquer,

a strip of cardboard 10 glued to the internal strip 9 by means of a vinyl adhesive or hot reactivated of the holt-melt type,

a strip 8 of a cardboard / paper / polyethylene complex which is glued, on its cardboard face, against the cardboard strip 10, and the other face of which faces the outside of the tube,

- a strip of crosslinked polyethylene foam 7,

a strip 11 of a cardboard / paper / polyethylene complex, the polyethylene face of which faces the foam strip 7, a strip of cardboard 12 glued against the cardboard face of the strip 11, - And finally a second strip of cardboard 13, glued to the strip 12, the glues used are still of the holt-melt type.

Hot air nozzles 15, disposed between the strips 8, 11 of the cardboard / paper / polyethylene complex and the foam strip 7, blow, both towards said strips 8, 11 and towards strip 7, a stream of hot air causing the resumption of the polyethylene crosslinking phenomenon. When pressed against one another on the mandrel 14, these bands 8, 11 and -7 se. then weld autogenously while cooling.

According to a very advantageous characteristic of the invention, hot air nozzles, not shown in the figures, are arranged along the strip of foam 7. In this way, the contiguous turns formed by the latter on the mandrel 14 are welded also to each other by their slices.

The heat-insulating tubes produced by the process of welding, by blowing with hot air, one or more strips of foam onto one or more strips of a complex, at least one face of which has a polyethylene film, can be used for any use other than that of sleeve 1 of a heat-insulating package as described with reference to FIG. 1. In particular, tubes of any cross-section obtainable by this latter process or by a similar rolling process, and having moreover, a priori any number of strips of foam and strips of cardboard find their use in the production of conduits, sheaths or heat-insulating pipes intended for the circulation of aerolic fluids.

The heat-insulating packaging according to the invention is not expensive to manufacture, it is light and its cross section can be arbitrary. circular like that shown in the figures, oval, polygonal, without excluding any other shape better suited to the product to be preserved from heating. In this regard, the case of a cylindrical packaging of circular section is well suitable for the transport of bottles to be kept fresh (services offered by caterers, etc.).

By way of example, the respective heat losses of a packaging for bottles designed with a non-insulating central sleeve, that is to say made only from 5 layers of cardboard of 0.4 mm d, have been compared. 'thickness only, and of a heat-insulating packaging in accordance with what has just been described, with a strip of foam 7 of 4 mm thickness interposed between two layers of cardboard of 0.4 mm thickness on each of these faces. For a starting temperature of 2 ° C, the temperature rose after three hours by 10 ° C in the non-insulated packaging and only 5 ° C in the insulating packaging.

Claims

1 - Heat-insulated packaging particularly suitable for the transport of foodstuffs already packaged in boxes, bottles or the like, characterized in that it comprises at least one central insulating sleeve (1) around which is arranged a concentric tube (2) and slightly tightening, from a height less than that of said sleeve (1), said packaging also comprising a cap (4) slidably mounted on the upper part (la) of the sleeve (1) emerging from said tube (2) after being mounted around said sleeve (1). 2 - Insulated packaging according to claim 1, characterized in that at least the bottom (5) of the cap (4) is provided with a wafer (6) of polyethylene foam, or a similar insulating material, just engage, when closing said cap (4) on the upper part (la.) of the sleeve (1), in the neck of said sleeve (1). 3 - Insulated packaging according to any one of the preceding claims, characterized in that the sleeve (1) is formed by rolling, convolute or spiral, of at least one strip of cardboard and at least one strip of polyethylene foam . 4 - Insulated packaging according to the preceding claim, characterized in that the sleeve (1) comprises at least two layers of cardboard laminated one on the other, then at least one layer of polyethylene foam, then at least two other layers of cardboard laminated one on the other, the innermost cardboard layers not being glued to said layer of foam. 5 - Insulated packaging according to claim 3, characterized in that the sleeve (1) comprises at least two layers of cardboard laminated one on the other, then at least one layer of polyethylene foam, then at least two other layers of cardboard laminated one on the other, the innermost cardboard layers being glued to said layer of foam. 6 heat-insulating packaging according to the preceding claim, characterized in that the bonding of the foam strip on the cardboard layers is carried out by means of a hot-reactive glue of the holt-melt type, identical to that which can be used for laminating. strips of cardboard between them. 7 - Heat-insulating packaging according to claim 5, characterized in that the foam strip (s) (7) used for the manufacture of the sleeve (1) are strips of cross-linked polyethylene foam, a paper / polyethylene complex being bonded to the face internal strips of cardboard (8, 11) being in direct contact with said strip of foam (7), the bonding of the latter strip (7) on the strips of cardboard (8, 11) being effected by air blowing hot, on the one hand, on said foam strip (7) and, on the other hand, on the polyethylene face of the cardboard strips (8, 11). 8 - Insulated packaging according to any one of claims 3 to 7, characterized in that the turns of the foam strip (s) (7) are welded autogenously by their edges.