Improved food packaging

Abstract

The present invention relates to an improved bag with linear perforations in some parts of its embodiment, designed to promote recycling and manufactured by means of a specific extrusion process. The bag has a composition of materials that provide it with unique properties, including MLLDPE, LLDPE, LDPE, PP, anti-slip additive, anti-blocking additive and process aid. The method of manufacturing thereof guarantees quality and the desired characteristics.

Description

[0001] IMPROVED PACKAGING FOR FOOD FIELD OF INVENTION

[0002] The present invention relates to an improved polyethylene-polypropylene bag with linear perforations, as well as associated manufacturing methods. The invention focuses on providing a solution that improves the recyclability and tear resistance of bags, making them suitable for the transportation and storage of foodstuffs such as fruits, vegetables, and other produce.

[0003] BACKGROUND

[0004] Plastic bags, ubiquitous globally, are manufactured at a rate of one trillion each year. Plastic bags became popular in the 1960s due to their use in packaging and transporting products.

[0005] One of the first innovations in this field was the patent for the one-piece polyethylene bag by the Swedish company Celloplast, designed by engineer Sten Gustaf Thulin. These improved packaging efficiency.

[0006] On the other hand, polypropylene bags represent an alternative. These bags, made from the polypropylene polymer, offer notable advantages such as greater abrasion resistance, lightness, hygiene, and color versatility.

[0007] Another commonly used packaging option is traditional burlap, made from natural materials such as jute and polypropylene-based raffia. These burlap bags are woven into flat, L-shaped weaves and sewn together. These bags are used for packaging fruits, vegetables, and other foods, facilitating handling and keeping the packaged product fresher for longer. Depending on the material they are made from, they have disadvantages such as poor drape, fragility, fiber shedding, and color changes under sunlight. Furthermore, their strength decreases when wet and they can be prone to microbial and fungal attack in humid climates, making them less suitable for transport in these climates.

[0008] The raffia recycling process has gained importance in recent years, given the widespread use of this material. Companies and environmental organizations have sought solutions to reuse and recycle raffia sacks and convert them into new products. This process involves collecting, sorting, cleaning, shredding, and extruding raffia to obtain pellets that can be used as raw material in the manufacture of new polypropylene-based plastic materials. This process is very expensive and time-consuming, as more careful cleaning is required at the seams caused by the "L" stitching.In the state of the art, different packaging materials are known that use: a rectangular perforated plastic bag, with average perforations of 500 micrometers or less, where the number of perforations per unit of surface area of ​​the film, in the lower zone is greater than the perforation density of the upper zone (MX359296); a bag for preserving fruits and vegetables, with microperforations at the base and lower gussets, where the perforations are found in its two inner layers and are absent in the outer layer (MX343911); a bag with two opposite panels of plastic sheet, where one panel includes vertical slots in parallel rows and the other panel with horizontal slots in parallel rows, with a support strip with holes for hanging the bag (US4503561).

[0009] While there are different alternatives and options for storing fruits and vegetables, what is needed is a packaging material that is durable and maintains the stability of the food inside, and that its production process is efficient and highly recyclable. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1. Drawing of a polyethylene-polypropylene bag from its front face, described Ai as along the central surface between gussets, the gussets being called Fi and F2.

[0011] Figure 2. Drawing of a polyethylene-polypropylene bag from its back side, described Af as along the central surface between gussets, the gussets being called Ff and F2'.

[0012] Figure 3. Drawing of a polyethylene-polypropylene bag with linear perforations arranged interspersed in zones Ai and Af.

[0013] Figure 4. Drawing of a polyethylene-polypropylene bag with linear perforations arranged interspersed in zones F1, F2, F1' and F2'.

[0014] Figure 5. Drawing of linear perforations with interleaved arrangement of the polyethylene bag

[0015] - polypropylene and describing Si configuration of horizontal separation between the linear openings (ai-ai and 32-82).

[0016] Figure 6. Drawing of linear perforations with interleaved arrangement of the polyethylene bag

[0017] - polypropylene and describing S2 configuration of horizontal separation between the linear openings (ai-a2).

[0018] Figure 7. Drawing of linear perforations with interleaved arrangement of the polyethylene bag

[0019] - polypropylene and describing S3 configuration of vertical separation between the linear openings (ai-ai and 32-82).

[0020] OBJECT OF THE INVENTION

[0021] The object of the present invention is to provide an improved polyethylene-polypropylene bag with linear perforations along its length, as well as an associated manufacturing method, through a suitable configuration, which solves the problem of the lack of tear resistance in conventional bags, while maintaining the stability of the product. A further object of the present invention is to provide a packaging material in the form of a polyethylene-polypropylene bag with improved recyclability compared to conventional burlap.

[0022] DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention relates to a flexible packaging in the form of a bag for preserving and transporting food such as: vegetables, fruits and vegetables, among others for industrial or home application. The bag comprises 3 layers of polyethylene - polypropylene based polymers and has linear openings (a) in at least a portion of the bag, where the linear openings have: a measurement (b) between the range of 30mm to 55 mm high with respect to (c), the horizontal separation S between the linear openings (ai-ai and 82-82) has a measurement of 18 mm to 36 mm, the horizontal separation S2 between the linear openings (81-82) has a measurement of 9 mm to 18 mm, and the vertical separation S3 between the linear openings (ai-ai and 82-82) has a measurement of 30 mm to 55 mm, with sealing at the bottom of the bag, obtained by the extrusion process.

[0024] In accordance with the present invention, the following are different concepts that are used to describe the invention and its operation:

[0025] "Plastic bag" refers to a flexible packaging material that has an opening at one of its ends, which serves to place products or objects inside. The composition of the bag contains 50% or more of at least one polymer and can be rectangular or square in shape depending on the configuration applied at the time of manufacture. In the present invention, the concept of "plastic bag" or "bag" is used equivalently to refer to the packaging material object of the invention. In particular, the rectangular-shaped bag is configured such that when placed on a flat surface, it has two identical layers one on top of the other and optionally has gussets.

[0026] "Gusseted bag" refers to a bag that, in its configuration, features a special mechanism that provides greater capacity through the "gusset," a fold at the bottom of the bag or on the sides of the bag. When expanded, the bag's capacity increases compared to the closed bag. In the present invention, the gusset is located on the sides of the bag.

[0027] “Flexible packaging” refers to a type of lightweight, easy-to-handle packaging, made primarily of plastic in the form of bags or rolls with or without printing, formed by extrusion, lamination, coating, coextrusion, or other methods known in the art.

[0028] "Polymer" refers to a compound, which may be of synthetic, natural, or chemical origin, obtained through a process known as polymerization, by the repetition of structural units. Among the polymers used in the present invention are polyethylene (PE) and polypropylene (PP).

[0029] “Polyethylene”, also referred to as “PE”, is a synthetic polymer with an unbranched linear chain, with a base unit (CHb-CHbjn, obtained by polymerization of ethylene (CH2-CH2), with a molecular weight in the range of 200,000 to 500,000.

[0030] “LDPE” or “low-density polyethylene” corresponds to a synthetic polymer with a highly branched chain structure, with a density between 0.93 and 0.97 g / cm 3 .

[0031] “LLDPE” or “linear low-density polyethylene” corresponds to a synthetic polymer with a linear chain with multiple numbers of short branches, with a density between 0.915-0.925 g / cm 3 . “mLLDPE” or “metallocene linear low-density polyethylene” corresponds to a synthetic linear chain polymer with a density between 0.902-0.936 g / cm 3 . It is manufactured using metallocene catalysts (a compound of general formula (CsRs M, where M a metal selected from V, Cr, Mn, Fe, Co, Li, Na, K, Mg or Fe). “Extrusion” is a plastics manufacturing technique that involves the homogeneous melting of a thermoplastic material that is in the form of pellets, powder or granules; by applying pressure, the molten material is expelled acquiring the desired shape during the process.

[0032] “Anti-slip additive” is a chemical substance or component added to a material during manufacturing to improve its ability to resist slipping or sliding on surfaces.

[0033] “Anti-blocking additive” is a chemical or component added during the plastic bag manufacturing process to prevent the plastic layers from sticking together and blocking, i.e., from sticking together unintentionally.

[0034] “Processing aid” is any substance used to improve or facilitate a specific production process.

[0035] “Recyclability” is the ability of the bag to be collected, processed, and transformed back into the product, rather than being discarded as waste.

[0036] In a preferred embodiment, the present invention separates the polyethylene-polypropylene bag on its front face into sections, where the section called Ai is the central surface of the bag between the gussets and where the gusset section is called Fi and F2, as can be seen in Figure 1.

[0037] In a preferred embodiment, the present invention separates the polyethylene-polypropylene bag on its rear face into sections, where the section called A / is the central surface of the bag between the gussets and where the gusset section is called F / and F2', as can be seen in Figure 2.

[0038] In a preferred embodiment, the present invention openings (a) have a linear shape when the bag is flattened horizontally on a flat surface, with a measurement that is in the range of 30 mm to 55 mm.

[0039] In one embodiment, the linear openings (a) are located on surfaces Ai and A along the central surface of the bag between bag gussets of the same size and configuration, where the opening size is 30 mm to 55 mm. In this embodiment, the gussets are free of the linear openings (a), as shown in Figure 3.

[0040] In a further embodiment, the linear openings (a) are located on the surfaces F1, F2, F1' and F2' along the side gussets of the bag, with the same size and configuration, where the opening size is from 30 mm to 55 mm. In this embodiment, the central surface of the bag between the gussets of the bag is free of the linear openings (a), as shown in Figure 4.

[0041] The linear openings (a) are located in such a way that they present the configuration described in Figure 5, Figure 6 and Figure 7 to form a network, where:

[0042] - the horizontal separation If between the linear openings (ai-ai and 82-82) has a measurement of 18 mm to 36 mm,

[0043] - the horizontal separation S2 between the linear openings (81-82) has a measurement of 9 mm to 18 mm, and

[0044] - the vertical separation S3 between the linear openings (ai-ai and 82-82) has a measurement of 30 mm to 55 mm. In a further embodiment, the flexible bag-shaped packaging for preserving and transporting food, vegetables, fruits, and greens comprises three layers of polyethylene-polypropylene-based polymers, wherein the composition comprises the following components:

[0045] In one embodiment, the present invention comprises a flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polymers, wherein at least one of the layers comprises a mixture of metallocene linear low-density polyethylene, linear low-density polyethylene and low-density polyethylene.

[0046] In one embodiment, the present invention comprises a flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polymers, wherein at least one of the layers comprises a mixture of metallocene linear low-density polyethylene, linear low-density polyethylene, low-density polyethylene and polypropylene.

[0047] In one embodiment, the present invention comprises a flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and vegetables comprising 3 layers of polymers, wherein the intermediate layer comprises polypropylene. In one embodiment, the present invention comprises at least one anti-slip additive selected from FB-20, modified polypropylene, EVA (ethylene-vinyl acetate), stearic acid, micronized high-density polyethylene (HDPE), silica powder, ethylene-butylene copolymer (EB), zinc oxide, aluminum particles, thermoplastic polyurethane (TPU), polyurethane powder, silicone emulsions, silicone polymers and combinations thereof.In one embodiment, the present invention comprises at least one anti-block additive selected from FCU, micronized talc, powdered amorphous silica, micronized calcium carbonate, micronized titanium dioxide, low density polyethylene (LDPE), high density polyethylene (HDPE), micronized polypropylene, powdered starch, and combinations thereof. In one embodiment, the present invention comprises at least one processing aid component selected from AMF, BHT (toluene butylhydroquinone), HALS UV stabilizer, stearic acid, motana wax, oleic acid, zinc stearate, calcium stearate, precipitated silica, polydimethylsiloxane, surface couplers to improve adhesion of inks, coatings, thermoplastic polymers, and combinations thereof.

[0048] A preferred method for manufacturing flexible packaging in the form of a bag for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polyethylene-polypropylene based polymer and having linear openings (a) in at least a portion of the bag, obtained by the extrusion process, comprises the steps of:

[0049] I. Extrude the bag in 3 layers, where each layer has 3 dispensers,

[0050] II. Program the recipe with the following components: metallocene linear low-density polyethylene; linear low-density polyethylene; low-density polyethylene; polypropylene; anti-slip additive; anti-blocking additive; and process aid, on a control panel with the dosage already established.

[0051] III. Extrude the mixture of polyethylene and polypropylene at a temperature of 180°C to 280°C, until the balloon is formed where the film is solidified by cold air (temperature 25°C), IV. Pass to the scanner to measure and control the thickness of the film and is directed to the flattening device where the film is compacted and directed to the reversible platform,

[0052] V. By means of guide rollers it reaches the bellows device where it forms the bellows and is adjusted to the indicated measurement.

[0053] VI. Move to the perforating roller where the bag openings are generated.

[0054] Vil. Enter the winder, where the film is wound to generate the bag rolls, and

[0055] VIII. Pass the coil to a bagging machine where it is unwound and cut by means of a blade with linear movement and sealed by means of a flat resistance (120°C) with the specified dimensions.

[0056] In one embodiment, the present invention comprises a flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polymers, wherein the first layer comprises a mixture of metallocene linear low-density polyethylene, linear low-density polyethylene and low-density polyethylene, the second layer comprises 10% polypropylene and the third layer comprises polyethylene.

[0057] EXAMPLES

[0058] Below, different arrangements of linear perforations, as well as their sizes, are presented in a descriptive, non-limiting manner:

[0059] Example 1: Design with cuts between the bellows.

[0060] A bag was made with 3 layers of polyethylene-polypropylene based polymers with linear openings in an interleaved arrangement in sections Ai and Af, where the linear openings have the following measurements:

[0061] Example 2: Design with cuts in the bellows.

[0062] A bag was made with 3 layers of polyethylene-polypropylene based polymers with linear openings in an interleaved arrangement in sections Fi, F2 and F1 F2', where the linear openings have the following measurements: Example 3: Design with cuts between the bellows with continuous arrangement.

[0063] A bag was made with 3 layers of polyethylene-polypropylene based polymers with linear openings in a continuous arrangement in sections Ai and Ai' where the linear openings have the following measurements:

[0064] Example 4: Design with smaller cuts between the gussets in a staggered arrangement. A bag was made with three layers of polyethylene-polypropylene-based polymers with linear openings in a staggered arrangement in sections Ai and Af, where the linear openings have the following dimensions:

[0065] Example 5: Gusseted bag formulation

[0066] Example 6: Manufacturing of gusset bag with openings

[0067] Gusset bags with linear openings were manufactured using the compositions of examples E1, E2 and E3, according to the following steps:

[0068] I. The bag is extruded in 3 layers, using 3 dispensers,

[0069] II. The recipe was programmed with the following components: metallocene linear low-density polyethylene; linear low-density polyethylene; low-density polyethylene; polypropylene; anti-slip additive; anti-blocking additive; and process aid, on a control panel with the dosage already established.

[0070] III. When extruding the mixture of polyethylene and polypropylene, the temperature is adjusted between 180°C and 280°C, until the balloon is formed where the film is solidified by means of cold air (temperature 25°C),

[0071] IV. The film thickness was measured and controlled by the scanner and the film was compacted using the flattening device and directed to the reversible platform, V. Form the bellows with the adjustment to the predetermined measurement,

[0072] VI. The bag openings are created using the perforating roller.

[0073] Vile. The film was wound to generate the rolls of the bag, and

[0074] VIII. It was cut by means of a linear displacement knife and sealed by means of a flat resistance (120°C) with the predetermined dimensions.

[0075] Example 7: Characterization of the gusset bag with openings.

[0076] Example 8: Comparison of polyethylene - polypropylene bags, in product stability.

[0077] What was previously presented in the product stability tables is described as “No changes” when the product has not suffered any alteration or damage, and remains in the same state as when it was placed in the polyethylene - polypropylene bag, it is described as “Product shows changes” when the product has suffered alterations or damage, observing the presence of humidity and opacity in the polyethylene - polypropylene bag, and it is described as “Product decomposition” when the product has the presence of microorganisms, more specifically fungi and the presence of humidity and opacity continues in the polyethylene - polypropylene bag.

Claims

CLAIMS Having described the invention, the following claims are claimed as property:

1. A flexible packaging in the form of a bag for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polyethylene-polypropylene based polymers and having linear openings (a) in at least a portion of the bag, wherein the linear openings have: a measurement (b) between the range of 30 mm to 55 mm high with respect to (c), the horizontal separation S between the linear openings (ai-ai and a2-a2) has a measurement of 18 mm to 36 mm, the horizontal separation S2 between the linear openings (31-82) has a measurement of 9 mm to 18 mm, and the vertical separation S3 between the linear openings (ai-ai and 82-82) has a measurement of 30 mm to 55 mm, with sealing at the bottom of the bag, obtained by the extrusion process.

2. A flexible bag-shaped packaging for preserving and transporting food, vegetables, fruits and greens according to claim 1, wherein the linear openings are located in the gusset of the bag.

3. A flexible bag-shaped packaging for preserving and transporting food, vegetables, fruits and greens according to claim 1, wherein the linear openings are located in the center of the bag.

4. A flexible packaging for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polyethylene-polypropylene based polymers according to claim 1, having a rectangular bag shape with linear openings to form a network.

5. A flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polymers obtained by the following composition: I. Metallocene linear low density polyethylene (mLLDPE) 39.0% ± 0.5%; II. Linear low density polyethylene (LLDPE) 40.0% ± 0.5%; III. Low density polyethylene (LDPE) 10.8% ± 0.5%; IV. Polypropylene (PP) 10% ± 0.5%; V. Anti-slip additive 0.0870% ± 0.02%; VI. Anti-blocking additive 0.0870% ± 0.02%; and Vil. Process aid 0.043% ± 0.02%.

6. A flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polymers according to claim 5, wherein the first layer comprises polyethylene, the second layer comprises 10% polypropylene and the third layer comprises polyethylene.

7. A flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens according to claim 5, wherein the anti-slip additive is FB-20, modified polypropylene, EVA (ethylene-vinyl acetate), stearic acid, micronized high-density polyethylene (HDPE), silica powder, ethylene-butylene copolymer (EB), zinc oxide, aluminum particles, thermoplastic polyurethane (TPU), polyurethane powder, silicone emulsions, silicone polymers and combinations thereof.

8. A flexible bag-shaped packaging with linear openings for preserving and transporting food, vegetables, fruits and greens according to claim 5, wherein the anti-blocking additive is FCU, micronized talc, powdered amorphous silica, micronized calcium carbonate, micronized titanium dioxide, low-density polyethylene (LDPE), high-density polyethylene (HDPE), micronized polypropylene, powdered starch and combinations thereof.

9. A flexible packaging in the form of a bag with linear openings for preserving and transporting food, vegetables, fruits and greens according to claim 5, wherein the processing aid is AMF, BHT (toluene butylhydroquinone), HALS UV stabilizer, stearic acid, motana wax, oleic acid, zinc stearate, calcium stearate, precipitated silica, polydimethylsiloxane, surface couplers to improve the adhesion of inks, coatings, thermoplastic polymers and combinations thereof.

10. A method for manufacturing a flexible packaging in the form of a bag for preserving and transporting food, vegetables, fruits and greens comprising 3 layers of polyethylene-polypropylene based polymer and having linear openings (a) in at least a portion of the bag, obtained through the extrusion process comprising the steps of: I. The bag is extruded in 3 layers, where each layer has 3 dispensers, II. The recipe is programmed with the following components: metallocene linear low-density polyethylene; linear low-density polyethylene; low-density polyethylene; polypropylene; anti-slip additive; anti-blocking additive; and process aid, on a control panel with the dosage already established. III. The mixture of polyethylene and polypropylene is extruded at 180°C to 280°C, until the balloon is formed where the film is solidified by cold air (temperature 25°C), IV. It then passes to the scanner to measure and control the film thickness and is directed to the flattening device where the film is compacted and directed to the reversible platform, V. Subsequently, by means of guide rollers, it reaches the bellows device where it forms the bellows and is adjusted to the indicated measurement. VI. Once finished, it passes to the perforating roller where the bag openings are generated. Vil. Finally, it enters the winder, where the film is wound to generate the bag rolls, and VIII. The coil passes to a bagging machine where it is unwound and cut by means of a linear displacement knife and sealed by means of a flat resistance (120°C) with the specified dimensions.

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