FR2761960A1 - POLYOLEFIN-BASED FILM FOR FORMING A FOLDING PACKAGE - Google Patents

Abstract

The film is characterized in that, a) it comprises a polyolefin-based film, b) the outer face of said film comprises a cold-sealing layer forming marked areas, c) the inner face of said film comprises an anti- adherent, possibly marked with respect to said marked areas.

Description

POLYOLEFIN-BASED FILM FOR FORMING A PACKAGE BY

FOLDING

FIELD OF THE INVENTION

  The invention relates to flexible films used in the packaging of solid or semi-solid portions by folding. By way of example of solid or semi-solid portions packed in flexible films, mention may be made of food products such as broths

KUB.

STATE OF THE ART

  For the typical packaging of food products such as KUB broths, a complex film is generally used successively consisting of a thin sheet of aluminum lacquered golden on the outside, a layer of wax in the center, and a layer of

  muslin paper inside, or in condensed designation: Al / wax / paper.

  The packaging of KUB broth blocks is carried out as follows, on an automatic machine: 1) from a spool of rope, a portion of film is cut on which said block is placed, 2) the assembly is placed in a folding box which makes it possible to carry out the succession of folds necessary for the packaging of said block by said portion of film, so as to obtain a folded packaged block, 3) said folded packaged block circulates between heating rails which melt the wax . This diffuse in the tissue paper and thus ensures the bonding of the different folds formed in 2). This produces a packaged, glued block. The glued wrapped blocks are then

  grouped in an overwrap, typically a cardboard box.

PROBLEMS POSED

  The problems posed by the traditional packaging film are of three types: - on the one hand, it has been observed that the traditional films lead to holes, in particular at the corners of said blocks, perhaps both by mechanical action corners of said blocks on said film, and possibly by the corrosive action of grains of salt of said

  block in the case of KUB broths.

  - on the other hand, the glued packaged block is relatively difficult to open.

  - finally, the traditional film is relatively expensive.

DESCRIPTION OF THE INVENTION

  According to the invention, the film for packaging rigid or semi-rigid blocks consisting of walls formed by folding and sealing said film is characterized in that, a) it comprises a polyolefin-based film, b) the outer face of said film comprises cold sealing layer forming marked areas, c) the inner face of said film comprises a non-stick layer, possibly

  marked with respect to said marked ranges.

  The invention requires the combination of the means described above: - a polyolefin-based film can be chosen because, on the one hand, it will have sufficient mechanical characteristics and it will most often constitute a sufficient moisture barrier for the product to condition, and on the other hand its cost is

relatively low.

  If the film according to the invention were required to have a low oxygen permeability, said polyolefin-based film could, in known manner, either be metallized or be replaced by a multilayer film comprising a layer of material with barrier properties , Phone

  as vinylidene chloride copolymers (PVDC) or EVOH.

  a cold sealing layer is necessary so that, during the packaging of said block in a cut portion of said film, generally using a folding box, the sealing of said identified areas is carried out immediately by simple contact of the facing parts during said folding, at least one of the parts facing each other during said folding being covered with a cold sealing layer. Thus, at the outlet of the folding box, said portion of film, once folded, will no longer have the possibility of unfolding,

  taking into account the memory effect of polyolefin films.

  - said polyolefin-based film must include a non-stick layer, possibly marked with respect to said marked areas, because without this, bonding on a reel would be observed: the sealing layer, deposited on the outside

  of said film, would stick or risk sticking to the inner face of the adjacent turn.

  Anti-adhesion treatments, intended in particular to avoid sticking between the turns

  of a film reel, are well known in themselves.

  Thanks to this combination of means, it was possible to solve the problem posed. Indeed, the film according to the invention has a much better resistance to the risk of punctures than the traditional film based on thin aluminum foil, and this both by the better mechanical resistance to punctures and by the better resistance to corrosion. In addition, the invention, which has succeeded in combating the memory effect of the thermoplastic films during the folding phase, uses this same memory effect to facilitate the unfolding of said block by the

final consumer.

  Finally, given the relatively low cost of polyolefin films compared to the cost of thin aluminum sheets, the film according to the invention is significantly more economical

  than films according to the state of the art.

DESCRIPTION OF THE FIGURES

  Figure I is a top view of the outer face of the film or portion of film (1) intended to form a package of a rigid or semi-rigid parallelepiped block having

  a rectangular base 32mm x 23mm, and 10mm high.

  The four marked areas (20) of cold sealing layer, hatched vertically, correspond to the formation, by folding, of the four side walls of the package to be formed. Each of the four areas (20) comprises two parts (201, 202) which, after folding along the lines (203), are opposite and adhere to each other, thus fixing the side walls

of the packaging to be formed.

  The four marked areas (21) of cold sealing layer, hatched horizontally, correspond to the formation, by folding, of the upper wall of

the packaging to be formed.

  Each of the four areas (21) comprises two parts (211, 212) which, after folding along the lines (213), are opposite and adhere to each other, thus fixing the upper wall

of the packaging to be formed.

  On the film (1) is carried an arrow (6) indicating the direction of unwinding of the film on reel. FIG. 2 is a bottom view of the interior face of the film or portion of film (1),

  having the same lateral positioning as in Figure 1.

  This inner face comprises two non-stick lateral bands (3), so that the marked areas (20, 21) of the outer face do not adhere to the inner face and

  thus allow the unwinding of the film reel.

  Between these two strips, and at one end of the portion (1) of film, is a beach

  marked (4) with fusible varnish.

  This area (4) is located at a distance of 10 mm from the edge, so as to leave an opening area (6) constituting for the consumer an easy grip of the film in order to

opening of the formed packaging.

  DETAILED DESCRIPTION OF THE INVENTION

  According to one embodiment of the invention, the location of said cold sealing layer is chosen as a function of said folding, so that, during said folding, any identified area or portion of identified area is brought into contact, respectively, or from another marked range, or from another part of the same marked range, so that, after folding said

  block, no free cold sealing layer remains.

  By cold sealing layer is meant a generic family of adhesive products, known in themselves often under the name of "coldseals", and which have the particularity

to cold-bond on themselves.

  According to another method, not shown in the figures, cold active adhesives can be used which can adhere to said polyolefin-based film, but which do not adhere

  not to this same film made non-stick.

  In this case, said marked areas of cold sealing (20,21) are of half the surface area and are limited to one half (201, 211) of area (20,21). According to the invention, said polyolefin-based film is preferably chosen from PP,

  I'OPP, I'OPP metallisé, expanded PP with pearlescent appearance.

  According to the invention, the inner face of said film must include an anti-

  adherent, possibly identified with respect to said identified areas.

  For this, either the inner face of said PP-based film is made non-stick, or the

  inner face of said PP-based film is coated with a layer of non-stick varnish.

  In the second case, this layer of varnish (3) can be identified, as illustrated in the

figure 2.

  According to another embodiment of the invention, said inner face can comprise said non-stick varnish in a marked layer, and a heat-sealing varnish in another marked layer, and offset with respect to said cold sealing layer, so that , in said film on reel, a layer of cold sealing of the external face of a turn,

  is not facing said layer of heat-sealing varnish from another turn.

  This modality is intended to increase, when it is made necessary in particular by local climatic conditions, the tightness of the formed packaging, the sealing of beaches

  (20,21) only ensuring that the packaging formed is not likely to unfold.

  Another object of the invention is constituted by the use of a film according to the invention for packaging food products in the form of rigid or semi-rigid blocks.

EXAMPLE OF IMPLEMENTATION

  A film was made as shown in Figures 1 and 2.

  An OPP film of 32 Rtm thick was used with a face made non-stick.

  On its outer face, a thickness of 4 μm of a commercial cold-sealing varnish (varnish to be applied) has been deposited, in a marked manner and along the ranges (20, 21) of FIG. 1

  alkyl acrylate base and natural latex).

  On its inner face, a layer (4) of fusible varnish has been deposited.

  commercial (varnish based on alkyl acrylate) of thickness 4 prm.

  We used this film to wrap KUB broth blocks on a standard machine

fitted with folding boxes.

  No particular problems were observed during the packaging of these blocks, which were

then put in cardboard.

  During transport and storage, no perforation of the said film was observed.

  The final opening, by the consumer, proved to be easier than that of the packaging according to the prior art, the polyolefin film tending, once broken

  the links between the sealed faces, to resume its initial planar shape.

Claims (7)

  1. Film for packaging rigid or semi-rigid blocks made up of walls formed by folding and sealing said film, characterized in that, a) it comprises a polyolefin-based film, b) the outer face of said film comprises a layer of cold sealing forming marked areas, c) the inner face of said film comprises a non-stick layer, possibly   marked with respect to said marked ranges.   2. Film according to claim 1, in which the location of said cold sealing layer is chosen as a function of said folding, so that, during said folding, any identified area or portion of identified area is brought into contact, respectively, either from another marked range, or from another part of the same marked range, so that, after   folding of said block, no free cold sealing layer remains.   3. Film according to any one of claims 1 to 2 wherein said film based   polyolefin is chosen from PP, OPP, metallized OPP, expanded PP with pearlescent appearance.   4. The film of claim 3 wherein the inner face of said PP-based film is made non-stick.   5. Film according to claim 3 wherein the inner face of said PP-based film is   coated with a layer of non-stick varnish.   6. Film according to claim 5, in which said inner face comprises said non-stick varnish in marked layer, and a heat-sealing varnish in another marked layer, and offset with respect to said cold sealing layer, so that, in said film on reel, a layer of cold sealing of the external face of a turn,   is not facing said layer of heat-sealing varnish from another turn.   7. Use of a film according to any one of claims 1 to 6 for packaging   of food products in the form of rigid or semi-rigid blocks.