Flexible package made of polymeric material with easy-opening feature

Abstract

A flexible package made of polymeric laminate material with an easy-opening feature, comprising a main precut (1) along the area defining the opening of the package, wherein a pair of secondary precuts (2) are positioned adjacent to but spaced apart from the ends of the main precut.

Description

[0001] FLEXIBLE PACKAGE MADE OF POLYMERIC MATERIAL WITH EASY-OPENING FEATURE

[0002] Field of the Invention

[0003] The present invention relates to packages made from flexible sheet materials, applicable to bags, pouches, and similar containers. In particular, the invention pertains to the technological field of gusset-type packages, also referred to as stand-up pouches with side gussets. More specifically, the invention is directed to such easy-to-open packages, in which a precut is made.

[0004] Background of the Invention

[0005] Numerous attempts have been made in the prior art to address the problem of quickly opening flexible packages. Patent documents such as CN213650480, US202301439, CA2354823, FR2693988, DE2336906, US3535409, W02004113193, IT2010MI0387, and WO200345816 disclose various systems for easy opening of bags and flexible packages. Many of these systems involve the use of precuts.

[0006] It is common for flexible packages with precut-based opening systems to tear beyond the limits of the precuts, often resulting in loss of the package contents.

[0007] Certain developments have attempted to solve this problem, such as Spanish patent ES2539577, which proposes a precut with a terminal configuration designed to prevent tearing beyond the end of the precut.

[0008] The present invention provides an easy-opening system for flexible packages that ensures the opening does not extend beyond the limits of the precut, thereby preventing rupture of a significant portion of the package and avoiding loss of its contents.

[0009] Summary of the Invention

[0010] The flexible package made of polymeric material with an easy-opening feature, which constitutes the main subject of the present invention, comprises a main precut along the area that defines the package opening, wherein, adjacent to the ends of said main precut, respective secondary precuts are positioned, spaced apart from said ends. Said secondary precuts are located at a distance of at least 0.1 mm from the ends of the main precut, and preferably extend laterally from the ends of the main precut, such that the angle formed by lines extending from each end of the secondary precuts to the adjacent end of the main precut is at least 40 degrees, more preferably at least 60 degrees, and even more preferably at least 90 degrees.

[0011] In a preferred embodiment, the secondary precuts comprise concave curves.

[0012] In another preferred embodiment, the precuts comprise laser cuts that penetrate the full width of the flexible polymeric film of the package to a depth of up to 85% of its total thickness.

[0013] In a further preferred embodiment of the package of the present invention, the main precut comprises laser cuts made in the cross direction (CD).

[0014] Brief Description of the Drawings

[0015] Figure 1 : Schematic representation of the main precut (1) and secondary precuts (2), which in this case are too small and fail to achieve an angle (4) greater than 40 degrees. The dashed lines represent the tearing that extends beyond the main precut due to the absence of a stop or barrier to halt its propagation.

[0016] Figure 2: Shows an embodiment of the invention, in which the angle (4) exceeds 40 degrees, and the secondary precuts are capable of containing any tearing that extends beyond the main precut when force is applied to open the package of the invention.

[0017] Figure 3: Schematic of a preferred embodiment of the present invention, where the secondary precuts (2) are concave curves and are spaced apart from the main precut by at least 0.1 mm.

[0018] Detailed Description of the Invention

[0019] The flexible package made of polymeric material with an easy-opening feature, which constitutes the main subject of the present invention, is preferably made from flexible polymers typically used in the manufacture of bags and flexible packaging for food products. The flexible polymeric films are those commonly used in packaging plants. These may include two-layer, three-layer, or multilayer materials.

[0020] Among the types of polymeric films that may be used as two-layer structures are: a) Biaxially Oriented Polypropylene (BOPP) I Inks I Adhesives / / Pigmented or nonpigmented Low-Density Polyethylene (LDPE); and b) Biaxially Oriented Polyethylene Terephthalate (BOPET) / Pigmented or non-pigmented

[0021] LDPE.

[0022] Examples of three-layer structures that may be used include:

[0023] A) BOPP I Inks I Adhesives / / Metallized BOPP I Adhesives / / Pigmented or non-pigmented

[0024] LDPE; and

[0025] B) BOPET I Inks I Adhesives / / Metallized BOPET (BOPET MET) I Adhesives / / Pigmented or non-pigmented LDPE.

[0026] Films such as BOPP and PET are manufactured using biaxial orientation processes, which impart high rigidity and, consequently, a very low elastic modulus. This contributes to more precise and less elastic tearing upon opening.

[0027] The package of the present invention comprises a main precut along the area that defines the opening of the package. As used in this document, a "precut" refers to a partial cut through the flexible polymeric sheet material. This cut affects only a portion of the thickness of the flexible material, weakening the line that constitutes the precut without reaching the inner surface of the package, thereby maintaining its sealing and airtightness.

[0028] The length of the main precut corresponds to the area that, when pulled, opens and defines the mouth of the package. The precuts may be made using various methods known in the art. Preferably, a laser is used with adjusted power settings to cut or score only a portion of the material’s thickness, more preferably to a depth not exceeding 85% of the total thickness. The main precut may be straight, curved, or have other configurations. Preferably, the main precut is straight and oriented in the cross direction (CD).

[0029] An essential feature of the present invention is that, adjacent to the ends of the main precut, respective secondary precuts are positioned, spaced apart from said ends.

[0030] During the development of various prototypes, the inventors encountered a technical problem: when the secondary precut intersects the end of the main precut — as is observed in Spanish patent ES2539577 — at least 40% of opening tests showed that the tearing of the flexible polymeric sheet material extended beyond the main precut and propagated through the secondary precut. This problem results in an unacceptable condition for commercialization, as the tear continues through the flexible polymeric laminate, often causing rupture and loss of contents. Through intensive inventive activity and various tests that demonstrated the efficacy of the invention, the inventors succeeded in developing a solution that is as simple as it is ingenious: the secondary precuts are spaced apart from the ends of the main precut.

[0031] In this way, when the tearing of the main precut — upon application of force to open the package — encounters a secondary precut at each end of the main precut, the tear is interrupted. The inventors determined that the tear can deviate from the line of the main precut by an angle of less than 20 degrees. Therefore, the span of the secondary precut must provide a total coverage of at least 40 degrees, as indicated by angle (4) in Figure 2.

[0032] Preferably, the secondary precuts are located at a distance of at least 0.1 mm from the ends of the main precut, more preferably at least 0.2 mm, and even more preferably at least 0.3 mm. Additionally, said secondary precuts preferably extend laterally from the ends of the main precut, and the angle formed by the lines extending from the ends of the secondary precuts to the adjacent end of the main precut (angle 4) is at least 40 degrees, more preferably at least 60 degrees, and most preferably at least 90 degrees, and may even exceed 100 degrees.

[0033] In a preferred embodiment, the secondary precuts comprise concave curves (i.e. , curves with their center oriented toward the end of the main precut), as illustrated in Figure 3. However, they may also take the form of straight lines, broken lines, or other geometries.

[0034] With regard to the secondary precuts, which may be referred to as end-of-path or terminal precuts, it is noted that various sizes were tested, including those configured perpendicularly to the main precut line, as shown in Figure 1. When these do not extend sufficiently to intercept tears deviating up to 20 degrees, they fail to perform their intended function. In Figure 1 , the dashed lines represent the propagation of the tear.

[0035] Another issue identified by the inventors is that, very often, when the secondary precut intersects the end of the main precut, a perforation is generated at the intersection due to double exposure of the film to the laser beam. This results in loss of airtightness in the package, with a failure rate of approximately 50%, which is also unacceptable for commercialization.

[0036] Another development by the inventors was the recognition that in blown film manufacturing processes, the machine direction (MD) exhibits a different tear resistance compared to the cross direction (CD). Therefore, in a preferred embodiment, the invention is implemented by forming a straight main precut oriented in the cross direction (CD). Application Examples

[0037] Example 1 :

[0038] Fabrication of the invention’s precuts in a food package.

[0039] The precuts are made using a slitter rewinder machine manufactured by Comexi, model S1 DT of Spanish origin, equipped with four CO2laser modules, each with a nominal installed power of 100 watts. The design of the precuts is created using the machine’s software, “Easy Pack,” and applied to a laminated material consisting of Biaxially Oriented Polypropylene (BOPP) I Inks I Adhesives / / Pigmented Low-Density Polyethylene (LDPE).

[0040] The process parameters are configured and saved as a production recipe for use across multiple production runs. These parameters include power settings (between 150 and 160 watts) and marking speed (between 1 ,000 and 3,000 milliseconds), which together determine the depth of the resulting precut and, consequently, the force required to open the package. This force must range between 2,500 and 3,500 g-force to ensure ease of opening while also preventing accidental opening during the product’s supply chain.

[0041] Both the main and secondary precuts are made simultaneously using the same laser module, with a focal length of 225 mm, achieving full penetration of the outer layer and up to 75% of the thickness of the inner film. The precut appears as continuous lines in Figure 3.

[0042] Example 2

[0043] The precut is made using a slitter rewinder machine manufactured by Comexi, model S1 DT of Spanish origin, which is equipped with four CO2laser modules, each with a nominal installed power of 100 watts. The design of the precut is carried out using the machine’s software, “Easy Pack,” and is applied to a three-layer material composed of Biaxially Oriented Polyethylene Terephthalate (BOPET) I Inks I Adhesives / / Metallized BOPET (BOPET MET) I Adhesives / / Pigmented Low- Density Polyethylene (LDPE).

[0044] The process parameters are configured and stored as a manufacturing recipe for use in various production runs. These parameters include power settings (between 150 and 160 watts) and marking speed (between 1 ,000 and 3,000 milliseconds), which determine the depth of the resulting precut and, consequently, the force required for opening. This force must range between 2,500 and 3,500 g-force to ensure easy opening while also preventing unintended openings throughout the final product’s supply chain.

[0045] Both the main and secondary precuts are made simultaneously by the same laser module, using a 225 mm focal length, achieving full penetration of the outer layer and up to 70% of the thickness of the film.

Claims

Claims1. A flexible package made of polymeric laminate material with an easy-opening feature, comprising a main precut (1) along the area defining the opening of the package, wherein a pair of secondary precuts (2) are positioned adjacent to but spaced apart from the ends of the main precut.

2. The flexible package according to claim 1 , wherein said secondary precuts are located at a distance of at least 0.1 mm from the ends of the main precut.

3. The flexible package according to claim 1 , wherein said secondary precuts extend laterally from the ends of the main precut and define an angle (4) formed by lines extending from the ends of the secondary precuts to the adjacent end of the main precut of at least 40 degrees.

4. The flexible package according to claim 1 , wherein said secondary precuts extend laterally from the ends of the main precut and define an angle (4) of at least 60 degrees.

5. The flexible package according to claim 1 , wherein said secondary precuts extend laterally from the ends of the main precut and define an angle (4) of at least 90 degrees.

6. The flexible package according to claim 1 , wherein said secondary precuts comprise concave curves (2) as shown in Figure 3.

7. The flexible package according to claim 1 , wherein said precuts comprise laser cuts that penetrate the flexible polymeric film of the package to a depth of up to 85% of its thickness.

8. The flexible package according to claim 1 , wherein said main precut comprises laser cuts made in the cross direction (CD).

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