Food packaging bag that is grease-resistant, and method for manufacturing such a bag
The process of manufacturing a fat-resistant paper-based packaging bag by using a film complex with a paper layer and a barrier layer, where the barrier layer forms a shutter to prevent fat penetration, addresses the issue of fat penetration in conventional paper-based bags, maintaining the bag's integrity and ecological design.
Patent Information
- Application Number
- FR2023001655
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-02-23
- Publication Date
- 2025-05-09
- Estimated Expiration
- 2043-02-23
AI Technical Summary
Conventional paper-based food packaging bags are prone to fat penetration, leading to aesthetic degradation and loss of mechanical resistance, especially when packaging fatty food products.
A process for manufacturing a fat-resistant paper-based packaging bag involves using a film complex with a paper layer and a barrier layer, where the longitudinal edge of the barrier layer overflows to form a shutter that is glued inside the bag, preventing direct contact between the paper layer and the food products.
This solution effectively prevents fat from penetrating the paper layer, maintaining the bag's aesthetic and mechanical properties while ensuring the bag remains simple, economical, and ecological in design.
Smart Images
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Abstract
Description
Title of the invention: Grease-resistant food packaging bag and method for manufacturing such a bag Technical field
[0001] The present invention relates to the technical field of packaging bags made from paper, in particular for the packaging of food products.
[0002] More particularly, the invention relates to a grease-proof food packaging bag and a method of manufacturing such a bag. Prior art
[0003] Known from the state of the art is a bag for packaging food products comprising a front wall and a rear wall, connected by gussets, a bottom, and a filling opening, the bag is manufactured from a film with a thickness of less than 200 μm, subjected to successive folding, welding and cutting operations to continuously form the packaging bag.
[0004] These types of bags can be used to package food for humans or animals.
[0005] Depending on the packaged food products, there is a need to make the bag resistant to grease that may be released by the products. In particular, the bag must be able to withstand at least the shelf life of the packaged food products.
[0006] Generally, these preformed bags are produced, continuously, from a single plastic film, such as PE with or without the addition of PP, or PE with the addition of PET, or any other materials perfectly known to a person skilled in the art, used in the field of food packaging, in particular.
[0007] For ecological reasons, however, the situation tends to favor bags made of paper.
[0008] One of the problems generally found is found in the packaging bags of food products, whether for human consumption (chips, peanuts, etc.) or animal feed (kibble).
[0009] Fats from food products come into contact with the bottom of the bag, soaking the bottom of the paper bag which loses, in addition to its general appearance, its mechanical resistance capabilities.
[0010] The bottom of the bag becomes greasy, which also poses problems in storing said bag.
[0011] To remedy this problem, it is known to treat the film constituting the bag, in particular during its manufacture, with per- and polyfluoroalkylated substances. (PFAS) which act as barriers to fats.
[0012] However, the use of this fluorinated substance is gradually being banned.
[0013] It is also known to use a bag made from a paper and polyethylene or polypropylene complex as an internal layer to make said bag waterproof.
[0014] However, the same problem arises at the level of the slices of the film constituting the bag which allows the fats to penetrate by capillarity, and soak the paper layer of the bag, which poses the same problems as mentioned above.
[0015] One solution to this problem is to coat the slices of film intended to be in contact with food products with a barrier glue or wax.
[0016] However, the process requires the addition of an additional element, such as wax, and is therefore not economical, nor free from any risk of grease penetrating the paper. Statement of the invention
[0017] One of the aims of the invention is therefore to propose a method for manufacturing a packaging bag made at least from paper which is resistant to the grease released by the packaged products, at least during their shelf life.
[0018] By resistant we mean that the grease does not soak into the paper so that its general appearance is not degraded and it retains its mechanical resistance capabilities.
[0019] For this purpose, a method has been developed for manufacturing a bag for packaging food products, from a film folded, cut and glued continuously to form a sheath defining a front wall, a rear wall, possibly connected by gussets, a bottom, and a filling opening. The film is in the form of a complex comprising on the external face a layer of paper and on the internal face a grease barrier layer.
[0020] The method according to the invention is remarkable in that it consists of using a film of which a longitudinal edge of the barrier layer projects beyond a longitudinal edge of the paper layer along a longitudinal edge of the sheath so as to define a barrier layer flap, free or folded and glued onto the paper layer, and, during the formation of the sheath, to glue the flap inside the sheath, in particular against a front or rear internal wall, to avoid any contact of the longitudinal edge of the paper layer with the food products intended to be packaged in the bag.
[0021] In this way, since the edge of the longitudinal edge of the paper layer of the film is not in direct contact with the food products, the risks of the paper becoming soaked with grease are reduced or even avoided.
[0022] It follows that the general aesthetics of the bag, as well as its mechanical resistance properties are preserved, while having a bag which is of simple, economical and ecological design.
[0023] According to a particular embodiment, the bottom of the bag is a flat bottom, well known in the state of the art.
[0024] The invention also relates to a bag for packaging food products resistant to grease from said food products.
[0025] In a known manner, the packaging bag is manufactured from a film in the form of a complex comprising on the external face a layer of paper and on the internal face a grease barrier layer, the film being folded back on itself, cut and glued to form a sheath defining at least one front wall and one rear wall, possibly connected by gussets, a filling opening, and a bottom, for example flat.
[0026] According to the invention, a longitudinal edge of the barrier layer projects beyond a longitudinal edge of the paper layer along a longitudinal edge of the sheath so as to define a barrier layer flap, free or folded and glued onto the paper layer, the flap also being glued inside the sheath to prevent any contact of the edge of the paper layer with the food products intended to be packaged in the bag.
[0027] According to a particular embodiment, the flap has a width of between 8 and 20 mm, for example 12 or 15 mm.
[0028] Preferably, the flap, and advantageously also the longitudinal edge of the paper layer, is (are) glued with a hot-melt glue.
[0029] The barrier layer is a layer of polypropylene, for example oriented in the machine direction, corresponding to the length of the bag, of cellulose, of polyester, of polyethylene, or of polylactic acid. Brief description of the drawings
[0030] Other advantages and characteristics will emerge more clearly from the following description, given as a non-limiting example of the packaging bag and its manufacturing method, from the attached drawings in which:
[0031] [Fig-1] is a view illustrating the film constituting the bag, in the form of a complex paper layer and grease barrier layer, with a free flap as a barrier layer.
[0032] [Fig.2] illustrates unwinding of the film showing fold lines for the gussets.
[0033] [Fig.3] illustrates the film folded into a sheath with the formation of gussets, and before cutting transverse at the bottom of the bag.
[0034] [Fig.4] illustrates the bonding of the edges of the sheath and the barrier layer flap.
[0035] [Fig.5] illustrates the opening and flattening of the bellows.
[0036] [Fig.6] illustrates the folding of the flat bottom.
[0037] [Fig.7] is a view similar to that of [Fig.l], with a barrier layer flap folded and glued onto the paper layer.
[0038] [Fig.8] illustrates the gluing of the edges of the sheath and the folded and glued flap of [Fig.7]. Detailed description of the invention
[0039] With reference to Figures 1 to 8, the invention relates to a method for manufacturing a bag (1) for packaging food products, manufactured from a film (2) in the form of a complex comprising on the external face a layer of paper (2a) and on the internal face a barrier layer (2b) to greases.
[0040] The barrier layer (2b) of the film (2), intended to be in contact with the packaged products and to act as a barrier to grease, is made of any suitable material, for example polypropylene, cellulose, polyester, polyethylene, polylactic acid, or any other material or coating known for its grease barrier properties. Preferably it is made of polypropylene oriented in the machine direction, namely in the length of the bag.
[0041] In a known manner, the quantity of plastic or more generally of material conferring the role of barrier to greases associated with the paper is low so as not to hinder the recyclability of the bag, and represents a maximum of 2%.
[0042] The invention resides in that a longitudinal edge of the barrier layer (2b) of the film (2) used to manufacture the bag projects beyond a longitudinal edge of the paper layer (2a), so as to define a flap (2b 1) of barrier layer (2b), for example made of oriented polypropylene, which is either free, see [Fig.l] and 4, or folded and glued onto the paper layer (2a), see [Fig.7] and 8.
[0043] The bag (1) is thus manufactured continuously from a strip of film (2) folded back on itself, by means of folding sheets for example, to form a sheath (3) defining a front wall (3a) and a rear wall (3b) connected by gussets (3c), a closed bottom (4), for example a flat bottom, and a filling opening (5).
[0044] When gluing the sheath, the polypropylene flap (2b 1) and the longitudinal edge of the paper layer (2a) are glued, longitudinally, inside the sheath, in particular against a front or rear wall of the bag. In practice, the method consists of depositing two lines of glue (6), for example hot-melt, along the edges to be glued, see [Fig. 4]. The gluing technique is already well known to those skilled in the art. According to [Fig. 4], the inside of the sheath (3) and therefore of the bag (1) is referenced (I), and the outside is referenced (E).
[0045] The flap (2b 1) therefore provides mechanical protection so that the edge of the paper layer (2a), and in particular its edge, is not in direct contact with the grease. rendered by the packaged food, so as to delay or even prevent the penetration by capillarity of fat into the paper constituting the film (2).
[0046] The flap (2bl) therefore extends over the entire length of the sheath and has a width of between 8 and 20 mm, for example 12 or 15 mm.
[0047] The sheath (3) is then cut transversely according to the length of the bag to be manufactured, see [Fig.3].
[0048] The bag preferably has a flat bottom (4) also called a square bottom or crossed bottom, formed by carrying out a first step consisting of folding outwardly a transverse end of the front wall (3a), so as to open the gussets (3c) and position them flat to form a triangle, then folding inwardly the side walls (4a) of the bottom, see figure [Fig.5].
[0049] A second step then consists of closing and gluing the flat bottom (4) by folding inwardly and successively transverse walls (4b) of the bottom, see [Fig.6], overlapping one on the other to close the bottom.
[0050] It is clear from the above that the invention does indeed provide a method for manufacturing a packaging bag made at least from paper which is resistant to grease released by the packaged products, at least during their shelf life.
Claims
Claims
1. Method for manufacturing a bag (1) for packaging food products, from a film (2) folded, cut and glued continuously to form a sheath (3) defining a front wall (3a), a rear wall (3b), a bottom (4), and a filling opening (5), the film (2) being in the form of a complex comprising on the external face a layer of paper (2a) and on the internal face a barrier layer (2b) to greases, characterized in that it consists in using a film (2) of which a longitudinal edge of the barrier layer (2b) projects beyond a longitudinal edge of the layer of paper (2a) along a longitudinal edge of the sheath (3) so as to define a flap (2b 1) of free barrier layer, and, during the formation of the sheath (3), in gluing the flap (2bl) to the inside (I) of the sheath (3) to avoid any contact of the longitudinal edge of the layer of paper (2a) with the products intended to be packaged in the
2. Bag. Bag (1) for packaging products, made from a film (2) in the form of a complex comprising on the external face a layer of paper (2a) and on the internal face a barrier layer (2b) to greases, the film (2) being folded on itself, cut and glued to form a sheath (3) defining at least a front wall (3a) and a rear wall (3b), a filling opening (5), and a bottom (4), characterized in that a longitudinal edge of the barrier layer (2b) overhangs relative to a longitudinal edge of the layer of paper (2a) along a longitudinal edge of the sheath (3) so as to define a flap (2b 1) of free barrier layer, the flap (2b 1) being glued to the inside (I) of the sheath (3) to avoid any contact of the edge of the layer of paper (2a) with the products intended to be packaged in the bag.
3. Packaging bag (1) according to claim 2, characterized in that the flap (2b 1) has a width of between 8 and 20 mm.
4. Packaging bag (1) according to one of claims 2 to 3, characterized in that the flap (2b 1) is glued with a hot-melt glue.
5. Packaging bag (1) according to one of claims 2 to 4, characterized in that the longitudinal edge of the paper layer (2a) is also glued to the inside (I) of the sheath (3).
6. Packaging bag (1) according to one of claims 2 to 5, characterized in that the barrier layer (2b) is a layer of polypropylene, cellulose, polyester, polyethylene, or polylactic acid.
7. Packaging bag (1) according to claim 6, characterized in that the barrier layer (2b) is a layer of polypropylene oriented in the direction of the length of the bag.