FR2796048A1 - PACKAGING FOR THE CONDITIONING OF A FOOD PREPARATION TO BE HEATED - Google Patents

Abstract

The sachet for food to be reheated has a heat sealed area (32) on the wall of the sachet of greater tear resistance than the sachet material. The contour of the heat sealed area defines at least one point on the surface of the sachet to allow tearing of the sachet material (14) under pressure. The point can be formed by a perforation (50) in the wall of the package.

Description

The present invention relates to a packaging for the conditioning-

  ment of a food preparation and its reheating, of the type comprising at least one flexible sheet, formed of at least one sealing film, which delimits

  at least partially a main containment enclosure for the preparation

  food ration, and means for venting said enclosure under the action of increasing the pressure in said enclosure, during

the rise in temperature.

  Nowadays, many prepared meals are packaged in trays closed by a lid formed by a flexible sheet, or

  in flexible bags made up of several flexible sheets assembled.

  In order to preserve the integrity of the dish, and aseptic conditions satisfied

  packaging, the packaging should be hermetically sealed when

transport and its sale.

  For reheating the prepared dish, it is possible to place the packaging in which the product is packaged directly in an oven

  in the microwave, or in a saucepan of hot water forming a double boiler.

  However, due to the large amount of water contained in the prepared dishes, it is advisable, before reheating the dish, to open the packaging, in order to prevent the pressure in it from becoming excessive

  and does not destroy the packaging by explosion.

  Opening the packaging manually is a tedious and sometimes awkward task. In addition, the user may forget to open the packaging before

  to reheat the preparation which is conditioned there, which leads to the des-

  packaging, making the dish non-consumable.

  Means for automatically venting such packages are already known for packaging trays closed by a

  flexible seal. These venting means include a mechanical valve

  as reported in a welding region of the lid on the tray.

  This valve is formed by a movable closure member kept elastic.

  on a seat delimited by the periphery of a discharge opening

  fear. This solution works satisfactorily. However, it has the drawback of requiring the addition of a mechanical valve, the installation of which is difficult during the manufacture of the packaging, and the

  cost increases the cost price of the packaging.

  The object of the invention is to propose a solution allowing the automatic venting of a package when the product contained therein is reheated, and the cost price of which is low.

  To this end, the invention relates to packaging for the packaging of

  ment of a food preparation and its reheating, of the aforementioned type,

  characterized in that said venting means comprise a region of said sheet, welded to a facing wall delimiting said enclosure, the

  weld having a tear strength greater than the breaking force

  tearing of the welding film, and in that the outline of the welded region defi-

  nit at least one point on the surface of said sheet promoting tearing-

welding film.

  According to particular embodiments, the packaging includes one or more of the following characteristics:

  said flexible sheet comprises at least one film associated with the film

  dant, and in that the or each associated film comprises in the region

  dée, a perforation or a perforation blank;

  - a metallic charge is placed in the vicinity of the sub-region

  point-shaped god; - Said welded region is defined in the free surface of the flexible sheet; and

  - Said welded region has a star shape.

  The invention will be better understood on reading the description which will

  follow, given only as an example and made with reference to the

  sins in which: - Figures 1 and 2 are elevational views respectively of the front and side of a packaging bag according to the invention; - Figure 3 is a sectional view of the means for venting the packaging of Figure 1 taken along line 111-111 before reheating of the product contained in the packaging; - Figures 4 and 5 are views similar to those of Figure 3 at successive stages of reheating

  - Figure 6 is an elevational view of the upper part of a sa-

  chet comprising an alternative embodiment of the venting means; and - Figure 7 is a sectional view taken along line VII-VII of

  means of venting the packaging of FIG. 6.

  The packaging shown in FIGS. 1 and 2 is a sachet intended for the packaging of a food preparation such as a soup 12. The sachet is formed by two main rectangular flexible sheets 14, 16

  arranged opposite and a bottom 18 consisting of a third flexible sheet.

  The two main flexible sheets 14, 16 are linked to each other along three adjacent edges, consisting of the two longitudinal edges of the sheets A and 20B and the upper edge denoted 20C. The fourth edge of the leaves

  14, 16 is bonded by welding to the edge of the sheet 18 forming the bottom.

  Each sheet 14, 16, 18 constituting the packaging is closed with two coextruded films made of polymer. The outer film of each sheet is made for example of polyester or polyamide and has a thickness of 15 to microns. It is designated by the same reference number as the sheet to which it belongs followed by the letter A.

  The inner film of each sheet is made for example of poly-

  ethylene or polypropylene and has a thickness of 50 to 100 microns. It is

  designated by the same reference number as the sheet to which it belongs

  is followed by the letter B. The inner film is a welding film allowing the

  bonding of two sheets by simply raising the temperature and pressing.

  The three sheets 14, 16, 18 define a main enclosure 22

  in which the food preparation 12 is contained. This is over

  mounted in the enclosure 22 by a volume 24 filled with air. In the upper part

  of the sachet, delimiting the volume filled with air 24, means are provided for venting the enclosure when the pressure in the packaging increases. The venting means 25 comprise a star-shaped weld 32 locally connecting the sheet 14 to the sheet 16 arranged opposite. The weld 32 is extremely resistant and in particular has resistance to

  the tearing greater than the tearing force of the sealing film 14B.

  The contour of the welded region defines at least one point on the

  surface of the sheet 14, favoring the tearing of the sealing film 14B.

  In the envisaged embodiment, the weld has a star shape with 6 branches. Each branch forms a point. The weld 32 is produced in a free region of the sheets 14 and 16, that is to say a region arranged

  away from the peripheral welds 20A, 20B, 20C.

  In addition, as shown in Figure 3, the sheet 14 is crossed

  a light 50 formed in the center of the welded region. This light trav-

  pours films 14A and 14B. The sheet 16 opposite is devoid of light

  and has a solid wall facing the light 50.

  As a variant, the two sheets 14 and 16 each have a light

  mière 50. These are arranged facing each other, both in the center of the

welded region.

  The bag according to the invention of which only one of the sheets has a

  light 50 is manufactured in the following manner.

  Sheets 14 and 16 are made and printed by being arranged

  in a band one after the other. They then form coils.

  While the sheets 14 are still joined to each other, the lights

  res 50 are provided in a region marked with each sheet intended to form the upper part of the sachet and to delimit the volume 24 filled with air

from the sachet.

  The lights 50 are cut for example using a punch

  during the circulation of the strip formed from the assembled sheets.

  The bags are then roughed out by cutting and welding the bottom 18, and the sheets 14 and 16. All the welds between the bottom and the sheets are made, with the exception of the weld 20C opposite the bottom 18 in order to

  allow subsequent filling of the sachet.

  Before filling the bag, the weld 32 is produced in order to bring together

  the sheets 14 and 16 all around the light 50 previously cut.

  This welding is carried out for example by two heating jaws in-

  tre which are enclosed sheets 14 and 16. The bearing surfaces of the jaws on the sheets have outer shapes of corresponding star

  to the desired shape for the weld.

  After completion of the star weld 32, the bags are filled

  then sealed by establishing the upper weld 20C.

  When the two sheets 14 and 16 both include lights

  res 50 formed in the center of the weld 32, the sachet open in its part

  upper tie is first outlined, while sheets 14 and 16 are cut

  provided with light. Star welding 32 is then carried out. Post-

  laughing at the completion of the weld or simultaneously, the slots 50 are formed in the center of the welded region by a cutting tool such

  than a punch. The bag is then filled and sealed.

  The functioning of a bag comprising a light 50 only

  through sheet 14 is now described.

  When the temperature in the bag rises, due to its

  heating, the pressure inside the enclosure 22 rises. Thus, the con-

  traces in the vicinity of the welded star-shaped region increase. The welded region being very resistant, the increase in pressure leads to delamination of the welding film 14B and of the external film 14A in the region where the welding film 14B is bonded to the internal film 16A of the facing sheet. Thus, an auxiliary chamber designated by the reference 60 in Figure 4 is created

between films 14A and 14B.

  Under the action of pressure continuing to increase in the main enclosure 22, the stresses in the delaminated welding film 14B, around the points defined by the branches of the star weld 32 become very

  large, which leads to tearing of the film welding 14B as shown

felt in figure 5.

  After this rupture, the main enclosure 22 is then in communication

  tion with the auxiliary chamber 60, itself opening to the outside through the perforation 50 passing through the outer film 14A. So the enclosure

  main is vented, allowing the evacuation of steam.

  The embodiment of Figures 6 and 7 shows the characteristics of the embodiment of the previous figures. However, in the region of realization of the star-shaped weld 32, metallic charges 70

  are arranged between the films 14A and 14B according to a central annular region

  trée on the through light 50. The metallic charges are advantageous-

  carefully placed in a printing ink applied between the two films. These metallic charges are for example aluminum powder,

  or bronze powder used in metallic inks or paints

  ques. It is understood that when using such packaging in a

  microwave, the presence of metallic charges 70 creates an increase in

  local temperature of the films 14A and 14B in the region carrying this charge. Thus, the tearing of the film 14B along the periphery of the star is facilitated by the local increase in temperature in this

zoned.

  According to an embodiment not shown, each of the sheets forming the packaging is produced by a single film, which corresponds to the

  removal of exterior films 14A and 16A.

  Whatever the embodiment, the perforation of the welding film 14B is optional, since in the case of a sheet made up of several

  films, only the perforation of the exterior films is useful.

  In the embodiment in which the two sheets 14 and 16 are perforated in the center of the welded region, metallic charges are

  advantageously interposed between the films of the two sheets on the

tower of lights.

  Alternatively, the lumen 50 is replaced by a blank of perforation

  tion made for example by mechanical or laser incision. Thus, the perfora-

  tion 50 does not appear on the packaging marketed, thus improving

  if the visual appearance of the packaging. However, the perforation blank opens by itself when the pressure in the auxiliary chamber increases

after rupture of the welding film 14B.

Claims (5)

  1.- Packaging for the packaging of a food preparation and its reheating, of the type comprising at least one flexible sheet (14), formed of at least one sealing film (14B), which at least partially delimits a main enclosure (22 ) for confining the food preparation (12), and means (25) for venting said enclosure (22) under the action of the increase in pressure in said enclosure (22), during the temperature rise, characterized in that said means (25) for venting   comprise a region (32) of said sheet (14), welded to a wall in re-   gard delimiting said enclosure, the weld having a tear strength greater than the tearing force of the welding film (14B), and in that the contour of the welded region (32) defines at least one point on the surface of said sheet favoring the tearing of the welding film (14B).   2. - Packaging according to claim 1, characterized in that said flexible sheet (14) comprises at least one film (14A) associated with the welding film (14B), and in that the or each associated film (14A) comprises in the region   welded (32), a perforation or a perforation blank (50).   3. - Packaging according to claim 1 or 2, characterized in that   that a metallic charge (70) is placed in the vicinity of the sub-region point (32).   4. - Packaging according to claim 3, characterized in that said   welded region (32) is defined in the free surface of the flexible sheet (14).   5. - Packaging according to claim 3 or 4, characterized in that   said welded region (32) has a star shape.