A multilayer composite film for the storage of fresh fruit

Abstract

The utility model discloses a multilayer composite film for fresh fruit storage, including BOPET film layer, nylon B film layer, nylon A film layer, PE / EVA film layer, PE / EVA film layer is formed by extrusion composite technology from PE film and EVA film, between BOPET film layer and nylon B film layer, between nylon B film layer and nylon A film layer, between nylon A film layer and EVA / PE film layer all are through polyurethane adhesive layer compound, and the inside surface of PE / EVA film layer has chitosan high polymer layer, and its thickness is 3 5mu m. The utility model discloses through polyurethane adhesive layer will BOPET film layer, nylon B film layer, nylon A film layer, PE / EVA film layer three times compound, and chitosan high polymer layer is the macromolecule polymer with micropore, makes multilayer composite film to the fruit sealed in the tray play the role of blocking breath and adsorbing ethylene, thereby has good fresh -keeping effect, and easily tear open, convenient to eat.

Description

Technical Field

[0001] This utility model relates to the field of composite film technology, specifically to a multilayer composite film for storing fresh fruit. Background Technology

[0002] With economic development and improved living standards, people's diets have shifted from a simple, subsistence-oriented approach to a diversified, nutritionally balanced one. The demand for fruit is increasing, and the requirements for its freshness are also rising. Fresh fruit continues to respire after harvesting, and this respiration is accompanied by metabolism, water evaporation, and ethylene production, further accelerating the ripening process. This storage environment also makes it easy for bacteria to grow and multiply rapidly, leading to fruit rot. Ethylene gas is a plant growth hormone. While ethylene promotes plant growth and fruit ripening, it is also a major cause of the perishability of fruits and vegetables. Ethylene induces senescence in fruits and vegetables, reducing their shelf life and significantly diminishing their visual and sensory quality. Therefore, we provide a multi-layered composite membrane for storing fresh fruit that can both block respiration and water vapor while also adsorbing ethylene gas to address these problems. Utility Model Content

[0003] The purpose of this invention is to provide a multilayer composite film for storing fresh fruit, in order to solve the problems existing in the background art.

[0004] To achieve the above objectives, this utility model provides a multilayer composite film for storing fresh fruit, comprising a BOPET film layer, a nylon B film layer, a nylon A film layer, and a PE / EVA film layer. The PE / EVA film layer is formed by extrusion bonding of a PE film and an EVA film. The BOPET film layer is bonded to the nylon B film layer, the nylon B film layer is bonded to the nylon A film layer, and the nylon A film layer is bonded to the PE / EVA film layer via polyurethane adhesive layers. The inner surface of the PE / EVA film layer is coated with a chitosan polymer layer, which serves as an ethylene adsorption layer with a thickness of 3-5 μm.

[0005] Furthermore, the BOPET film layer is disposed on the outermost layer of the multilayer composite film and also serves as a printed film layer, with a thickness of 12-15 μm.

[0006] Furthermore, the inner surface of the BOPET film layer is bonded to the nylon B film layer through a polyurethane adhesive layer, and the nylon B film serves as a barrier layer with a thickness of 12-15 μm.

[0007] Furthermore, the inner surface of the nylon B film layer is bonded to the nylon A film layer through a polyurethane adhesive layer, and the nylon A film layer serves as a barrier layer with a thickness of 12-15 μm.

[0008] Furthermore, the nylon B film layer is a nylon 6 film or a nylon 66 film, and the nylon A film layer is a nylon 6 film or a nylon 66 film.

[0009] Furthermore, the inner side of the nylon A film layer is bonded to one side of the EVA film of the PE / EVA film layer through a polyurethane adhesive layer. In the PE / EVA film layer, the EVA film serves as an easy-tear layer with a thickness of 5-8 μm, and the PE film serves as a heat-sealing layer with a thickness of 50-120 μm.

[0010] Furthermore, the thickness of the polyurethane adhesive layer is 2-3 μm.

[0011] Furthermore, the chitosan polymer layer is a microporous polymer with a pore size of 10-50 nm.

[0012] Furthermore, the total thickness of the multilayer composite film is 100-180 μm.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: This utility model uses a polyurethane adhesive layer to composite a BOPET film layer, a nylon B film layer, a nylon A film layer, and a PE / EVA film layer in three layers. The BOPET film layer prevents external light and oxygen from affecting the freshness of the fruit. The nylon B film layer and the nylon A film layer both have excellent water vapor barrier properties. Furthermore, the chitosan polymer layer coated on the inner side of the PE / EVA film layer is a microporous polymer. This multi-layer composite film can block the respiration of the fruit sealed in the tray and adsorb ethylene, thus providing excellent preservation. It is also easy to tear open and convenient for consumption. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the multilayer composite membrane structure according to an embodiment of the present invention.

[0016] Figure 2 This is a schematic diagram of the PE / EVA film structure of an embodiment of the present invention.

[0017] In the diagram: PE / EVA film layer 1, PE film 101, EVA film 102, Nylon A film layer 2, Nylon B film layer 3, BOPET film layer 4, polyurethane adhesive layer 5, chitosan polymer layer 6. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the embodiments of the present invention, and should not be construed as limiting the present invention.

[0019] In the description of the embodiments of this utility model, it should be understood that if the embodiments of this utility model involve directional indications, such as up, down, left, right, front, back, inside, outside, etc., the orientation or positional relationship of the indications is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the embodiments of this utility model and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this utility model.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] In this embodiment of the invention, unless otherwise explicitly specified and limited, terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part of a structure. They can be mechanical or electrical connections. They can be direct connections or indirect connections through an intermediate medium, and can represent the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention based on the specific circumstances.

[0022] Example 1

[0023] like Figure 1 and Figure 2As shown, this utility model embodiment provides a multilayer composite film for storing fresh fruit, including a BOPET film layer 4, a nylon B film layer 3, a nylon A film layer 2, and a PE / EVA film layer 1. The PE / EVA film layer 1 is formed by extrusion lamination of a PE film 101 and an EVA film 102. The BOPET film layer 4 and the nylon B film layer 3, the nylon B film layer 3 and the nylon A film layer 2, and the nylon A film layer 2 and the PE / EVA film layer 1 are all bonded together by a polyurethane adhesive layer 5. The nylon B film layer 3 is a nylon 6 film or a nylon 66 film, and the nylon A film layer 2 is a nylon 6 film or a nylon 66 film. The inner surface of the PE / EVA film layer 1 is coated with a chitosan polymer layer 6, which serves as an ethylene adsorption layer with a thickness of 3 μm. Chitosan is composed of N-acetyl- D-glucosamine and D-glucosamine are linear polysaccharides linked by β-1,4-glycosidic bonds. Under certain conditions, these polysaccharide chains can form a three-dimensional network structure with a certain porosity through intramolecular and intermolecular interactions, such as hydrogen bonds and van der Waals forces, thereby forming a microporous polymer.

[0024] In this embodiment, the BOPET film layer 4 is disposed on the outermost layer of the multilayer composite film and also serves as a printing film layer, with a thickness of 12μm.

[0025] In this embodiment, the inner surface of the BOPET film layer 4 is bonded to the nylon B film layer 3 through a polyurethane adhesive layer 5. The nylon B film layer 3 serves as a barrier layer and has a thickness of 12 μm.

[0026] In this embodiment, the inner side of the nylon B film layer 3 is bonded to the nylon A film layer 2 through a polyurethane adhesive layer 5. The nylon A film layer 2 serves as a barrier layer and has a thickness of 12 μm.

[0027] In this embodiment, nylon B film layer 3 is nylon 6 film, and nylon A film layer 2 is nylon 66 film.

[0028] In this embodiment, the inner side of the nylon A film layer 2 is bonded to one side of the EVA film 102 of the PE / EVA film layer 1 through the polyurethane adhesive layer 5. The EVA film 102 in the PE / EVA film layer 1 serves as an easy-tear layer with a thickness of 6μm, and the PE film 101 serves as a heat-sealing layer with a thickness of 100μm.

[0029] In this embodiment, the thickness of the polyurethane adhesive layer 5 is 2 μm.

[0030] In this embodiment, the pore size of the chitosan polymer layer 6 is 35 nm.

[0031] The composite membrane preparation process in this embodiment:

[0032] (1) Preparation of PE / EVA film: A PE film with a thickness of 100 μm is composited with an EVA film with a thickness of 6 μm by an extrusion composite process to prepare a PE / EVA film with a thickness of 106 μm.

[0033] (2) Composite of multilayer film: First, a 12μm nylon 66 film is bonded to one side of the EVA film of the above PE / EVA film layer using polyurethane adhesive. Then, a 12μm nylon 6 film is bonded to the other side of the nylon 66 film layer using polyurethane adhesive. Finally, a 12μm BOPET film is bonded to the other side of the nylon 6 film using polyurethane adhesive, forming a BOPET / nylon 6 / nylon 66 / EVA / PE composite film with a thickness of 148μm.

[0034] (3) Formation of multilayer composite film: A layer of chitosan polymer with a thickness of 3μm is coated on the inner side of the above-mentioned BOPET / nylon 6 / nylon 66 / EVA / PE composite film to form a multilayer composite film with a thickness of 151μm in this embodiment.

[0035] Example 2

[0036] like Figure 1 and Figure 2 As shown, this utility model embodiment provides a multilayer composite film for storing fresh fruit, including a BOPET film layer 4, a nylon B film layer 3, a nylon A film layer 2, and a PE / EVA film layer 1. The PE / EVA film layer 1 is formed by extrusion bonding of a PE film 101 and an EVA film 102. The BOPET film layer 4 and the nylon B film layer 3, the nylon B film layer 3 and the nylon A film layer 2, and the nylon A film layer 2 and the PE / EVA film layer 1 are all bonded together by a polyurethane adhesive layer 5. The inner surface of the PE / EVA film layer 1 is coated with a chitosan polymer layer 6, which serves as an ethylene adsorption layer with a thickness of 4 μm and a pore size of 35 nm.

[0037] In this embodiment, the BOPET film layer 4 is disposed on the outermost layer of the multilayer composite film and also serves as a printing film layer, with a thickness of 13μm.

[0038] In this embodiment, the inner surface of the BOPET film layer 4 is bonded to the nylon B film layer 3 through a polyurethane adhesive layer 5. The nylon B film layer 3 serves as a barrier layer and has a thickness of 13 μm.

[0039] In this embodiment, the inner side of the nylon B film layer 3 is bonded to the nylon A film layer 2 through a polyurethane adhesive layer 5. The nylon A film layer 2 serves as a barrier layer with a thickness of 13 μm.

[0040] In this embodiment, nylon B film layer 3 is nylon 6 film, and nylon A film layer 2 is nylon 66 film.

[0041] In this embodiment, the inner side of the nylon A film layer 2 is bonded to one side of the EVA film 102 of the PE / EVA film layer 1 through a polyurethane adhesive layer 5. In the PE / EVA film layer 1, the EVA film 102 serves as an easy-tear layer with a thickness of 8 μm, and the PE film 101 serves as a heat-sealing layer with a thickness of 95 μm.

[0042] In this embodiment, the thickness of the polyurethane adhesive layer 5 is 2 μm.

[0043] In this embodiment, the pore size of the chitosan polymer layer 6 is 35 nm.

[0044] The composite membrane preparation process in this embodiment:

[0045] (1) Preparation of PE / EVA film 1: A PE / EVA film with a thickness of 101 μm is prepared by extrusion composite process with an EVA film with a thickness of 6 μm on the outer side of a PE film with a thickness of 95 μm.

[0046] (2) Composite of multilayer film: First, a 13μm nylon 66 film is bonded to one side of the EVA film of the above PE / EVA film layer using polyurethane adhesive. Then, a 12μm nylon 6 film is bonded to the other side of the nylon 66 film layer using polyurethane adhesive. Finally, a 12μm BOPET film is bonded to the other side of the nylon 6 film using polyurethane adhesive, forming a BOPET / nylon 6 / nylon 66 / EVA / PE composite film with a thickness of 146μm.

[0047] (3) Formation of multilayer composite film: A layer of chitosan polymer with a thickness of 4μm is coated on the inner side of the above-mentioned BOPET / Nylon 6 / Nylon 66 / EVA / PE composite film to form a multilayer composite film with a thickness of 150μm in this embodiment.

[0048] Example 3

[0049] like Figure 1 and Figure 2 As shown, this utility model embodiment provides a multilayer composite film for storing fresh fruit, including a BOPET film layer 4, a nylon B film layer 3, a nylon A film layer 2, and a PE / EVA film layer 1. The PE / EVA film layer 1 is formed by extrusion bonding of a PE film 101 and an EVA film 102. The BOPET film layer 4 and the nylon B film layer 3, the nylon B film layer 3 and the nylon A film layer 2, and the nylon A film layer 2 and the PE / EVA film layer 1 are all bonded together by a polyurethane adhesive layer 5. The inner surface of the PE / EVA film layer 1 is coated with a chitosan polymer layer 6, which serves as an ethylene adsorption layer with a thickness of 5 μm.

[0050] In this embodiment, the BOPET film layer 4 is disposed on the outermost layer of the multilayer composite film and also serves as a printing film layer, with a thickness of 15μm.

[0051] In this embodiment, the inner surface of the BOPET film layer 4 is bonded to the nylon B film layer 3 through a polyurethane adhesive layer 5. The nylon B film layer 3 serves as a barrier layer and has a thickness of 15 μm.

[0052] In this embodiment, the inner side of the nylon B film layer 3 is bonded to the nylon A film layer 2 through a polyurethane adhesive layer 5. The nylon A film layer 2 serves as a barrier layer and has a thickness of 15 μm.

[0053] In this embodiment, nylon B film layer 3 is nylon 6 film, and nylon A film layer 2 is nylon 66 film.

[0054] In this embodiment, the inner side of the nylon A film layer 2 is bonded to one side of the EVA film 102 of the PE / EVA film layer 1 through a polyurethane adhesive layer 5. In the PE / EVA film layer 1, the EVA film 102 serves as an easy-tear layer with a thickness of 5 μm, and the PE film serves as a heat-sealing layer with a thickness of 90 μm.

[0055] In this embodiment, the thickness of the polyurethane adhesive layer 5 is 2 μm.

[0056] In this embodiment, the pore size of the chitosan polymer layer 6 is 35 nm.

[0057] The composite membrane preparation process in this embodiment:

[0058] (1) Preparation of PE / EVA film 1: A PE film with a thickness of 90 μm is composited with an EVA film with a thickness of 4 μm on the outer side of a PE film with a thickness of 90 μm by an extrusion composite process to prepare a PE / EVA film with a thickness of 94 μm.

[0059] (2) Composite of multilayer film: First, a 15μm nylon 66 film is bonded to one side of the EVA film of the above PE / EVA film layer using polyurethane adhesive. Then, a 15μm nylon 6 film is bonded to the other side of the nylon 66 film layer using polyurethane adhesive. Finally, a 15μm BOPET film is bonded to the other side of the nylon 6 film using polyurethane adhesive, forming a BOPET / nylon 6 / nylon 66 / EVA / PE composite film with a thickness of 145μm.

[0060] (3) Formation of multilayer composite film: A layer of chitosan polymer with a thickness of 5μm is coated on the inner side of the above-mentioned BOPET / nylon 6 / nylon 66 / EVA / PE composite film to form a multilayer composite film with a thickness of 150μm in this embodiment.

[0061] Comparative Example 1

[0062] Comparative Example 1 provides a multilayer composite film, which differs from Example 3 in that it includes a BOPET film layer 4, a nylon A film layer 2, and a PE / EVA film layer 1. The BOPET film layer 4 and the nylon A film layer 2, as well as the nylon A film layer 2 and the PE / EVA film layer 1, are all bonded together by a polyurethane adhesive layer 5.

[0063] Comparative Example 1: Composite membrane preparation process:

[0064] (1) Preparation of PE / EVA film 1: A PE film with a thickness of 90 μm is composited with an EVA film with a thickness of 4 μm on the outer side of a PE film with a thickness of 90 μm by an extrusion composite process to prepare a PE / EVA film with a thickness of 94 μm.

[0065] (2) Composite of multilayer film: First, a 15μm nylon 66 film is bonded to one side of the EVA film of the above PE / EVA film layer using polyurethane adhesive. Then, a 15μm BOPET film is bonded to the other side of the nylon 66 film layer using polyurethane adhesive, forming a BOPET / nylon 66 / EVA / PE composite film with a thickness of 128μm.

[0066] (3) Formation of multilayer composite film: A layer of chitosan polymer with a thickness of 5 μm is coated on the inner side of the above BOPET / Nylon 66 / EVA / PE composite film to form a multilayer composite film with a thickness of 133 μm as in Comparative Example 1.

[0067] Comparative Example 2

[0068] Comparative Example 2 provides a multilayer composite film, which differs from Example 3 in that it includes a BOPET film layer 4, a nylon B film layer 2, and a PE / EVA film layer 1. The BOPET film layer 4 and the nylon B film layer 3, as well as the nylon B film layer 3 and the PE / EVA film layer 1, are all bonded together by a polyurethane adhesive layer 5.

[0069] Comparative Example 2: Composite membrane preparation process:

[0070] (1) Preparation of PE / EVA film 1: A PE film with a thickness of 90 μm is composited with an EVA film with a thickness of 4 μm on the outer side of a PE film with a thickness of 90 μm by an extrusion composite process to prepare a PE / EVA film with a thickness of 94 μm.

[0071] (2) Composite of multilayer film: First, a 15μm nylon 6 film is bonded to one side of the EVA film of the above PE / EVA film layer using polyurethane adhesive. Then, a 15μm BOPET film is bonded to the other side of the nylon 6 film layer using polyurethane adhesive to form a BOPET / nylon 6 / EVA / PE composite film with a thickness of 128μm.

[0072] (3) Formation of multilayer composite film: A layer of chitosan polymer with a thickness of 5 μm is coated on the inner side of the above BOPET / Nylon 6 / EVA / PE composite film to form a multilayer composite film with a thickness of 133 μm as in Comparative Example 2.

[0073] Table 1 below shows the performance test results of the multilayer composite films of Examples 1-3 and Comparative Examples 1 and 2 applied to the storage of fresh apples.

[0074] Table 1. Performance test results of the multilayer composite films of Examples 1-3 and Comparative Examples 1 and 2 applied to the storage of fresh apples.

[0075]

[0076] As can be seen from the table above, the water vapor transmission rate and oxygen transmission rate of the multilayer composite films of Examples 1-3 and Comparative Examples 1 and 2 are all less than 0.5, which indicates that they have good barrier properties when used for packaging fresh apples. At the same time, the ethylene concentration in the cold storage (0-3℃) where fresh apples were stored under their packaging was less than 5ppm, and the greater the thickness of the chitosan polymer, the lower the ethylene concentration. This shows that they can effectively adsorb ethylene in the system, thus proving that they have a good preservation effect. In addition, compared with Comparative Examples 1 and 2 which have a single-layer nylon film structure, the double-layer nylon film structure of Examples 1-3 significantly improves the barrier properties of the multilayer composite film, and also improves the flexibility and cold resistance of the multilayer composite film.

[0077] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A multilayer composite film for storing fresh fruit, characterized in that, The film includes a BOPET film layer (4), a nylon B film layer (3), a nylon A film layer (2), and a PE / EVA film layer (1). The PE / EVA film layer (1) is formed by extrusion composite process of PE film (101) and EVA film (102). The BOPET film layer (4) and the nylon B film layer (3), the nylon B film layer (3) and the nylon A film layer (2), and the nylon A film layer (2) and the PE / EVA film layer (1) are all composited by polyurethane adhesive layer (5). The inner side of the PE / EVA film layer (1) is coated with a chitosan polymer layer (6). The chitosan polymer layer (6) serves as an ethylene adsorption layer and has a thickness of 3-5 μm.

2. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The BOPET film layer (4) is disposed on the outermost layer of the multilayer composite film and also serves as a printing film layer, with a thickness of 12-15 μm.

3. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The inner side of the BOPET film layer (4) is bonded to the nylon B film layer (3) through a polyurethane adhesive layer (5). The nylon B film layer (3) serves as a barrier layer with a thickness of 12-15 μm.

4. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The inner side of the nylon B film layer (3) is bonded to the nylon A film layer (2) through a polyurethane adhesive layer (5). The nylon A film layer (2) serves as a barrier layer with a thickness of 12-15 μm.

5. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The nylon B film layer (3) is a nylon 6 film or a nylon 66 film, and the nylon A film layer (2) is a nylon 6 film or a nylon 66 film.

6. The multilayer composite film for storing fresh fruit according to claim 1, characterized in that, The inner side of the nylon A film layer (2) is bonded to one side of the EVA film (102) of the PE / EVA film layer (1) through a polyurethane adhesive layer (5). In the PE / EVA film layer (1), the EVA film (102) serves as an easy-tear layer with a thickness of 5-8 μm, and the PE film (101) serves as a heat-sealing layer with a thickness of 50-120 μm.

7. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The thickness of the polyurethane adhesive layer (5) is 2-3 μm.

8. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The chitosan polymer layer (6) is a microporous polymer with a pore size of 10-50 nm.

9. A multi-layered composite film for storage of fresh fruits as claimed in claim 1 wherein, The total thickness of the multilayer composite film is 100-180 μm.

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