Environment-friendly separable composite packaging film

Abstract

The utility model relates to the technical field of food packaging, and discloses an environment-friendly separable composite packaging film which is characterized by comprising a protective layer, a printing layer, a water-soluble release coating, a base material layer and a cold sealing adhesive layer which are sequentially arranged from outside to inside, and the thickness of a dry film formed after the water-soluble release coating is cured is 0.5-1.2 microns. The composite packaging film has the technical effects that the printing layer and the base material layer can be quickly separated in the recovery treatment process, and the material integrity of the composite packaging film after separation and recovery is improved, and the composite packaging film is environment-friendly, safe and high in recovery rate.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the food packaging technical field, concretely relates to a kind of environment-friendly separable composite packaging film. BACKGROUND

[0002] Food packaging film plays a role in blocking food and external environment during the transportation and storage of food, reduces the influence of physical damage or chemical pollution on food, and maintains the freshness and quality of food. Common food packaging film is a multi-layer structure, mainly including a printing layer and an inner layer arranged in turn from the outside to the inside. The printing layer is attached to the surface of the inner layer by printing, and the printing layer is solidified to form patterns or marks. The inner layer has certain low adsorption and anti-permeation properties to ensure the quality and safety of food.

[0003] At present, the market demand for recyclable environment-friendly food packaging film is growing. By peeling off the multi-layer structure of the food packaging film, the food packaging film can be classified and recycled, which helps to reduce the pollution of discarded food packaging film to the environment and plays a role in saving resources and promoting sustainable development.

[0004] However, the printing layer is usually directly compounded with the inner layer. The printing layer and the inner layer are strongly bonded due to physical or chemical bonding. During the recycling process of the food packaging film, it is difficult to ensure the integrity of the material by mechanical peeling, and the base layer is easily broken due to stretching under external force during the peeling process. SUMMARY

[0005] To solve the problems of the prior art, the utility model provides an environment-friendly separable composite packaging film. The printing layer and the base layer are separated by a water-soluble release coating during recycling. It has the characteristics of environmental safety, high recycling rate and low production cost, and improves the material integrity of the composite packaging film after separation and recycling.

[0006] The technical effects achieved by the utility model are realized by the following technical aspects:

[0007] The utility model provides an environment-friendly separable composite packaging film, which includes a protective layer, a printing layer, a water-soluble release coating, a base layer and a cold seal adhesive layer arranged in turn from the outside to the inside. The dry film thickness of the water-soluble release coating after solidification is 0.5-1.2 μm.

[0008] In some implementations, the water-soluble release coating is made of a mixture of polyvinyl alcohol and hydroxypropyl methylcellulose.

[0009] In some implementations, the water-soluble release coating has a peel strength of ≤0.5 N / 15 mm with the printing layer in an alkaline solution.

[0010] In some implementations, the protective layer is an aqueous polyurethane-acrylate copolymer layer reverse gravure coated on the printing layer.

[0011] In some implementations, the aqueous polyurethane-acrylate copolymer layer has a thickness of 0.8-1.2 μm.

[0012] In some implementations, the substrate layer is one of synthetic paper, MOPP film, aluminized paper or kraft paper.

[0013] In some implementations, the substrate layer has a thickness of 28-120 μm.

[0014] In some implementations, the cold seal adhesive layer is a styrene-isoprene-styrene-based hot melt adhesive layer.

[0015] In some implementations, the cold seal adhesive layer has a thickness of 2.5-4.0 μm.

[0016] In some implementations, the printing layer is a gravure ink layer.

[0017] In summary, the present application has at least the following advantages:

[0018] The environmental protection type separable composite packaging film provided by the present application has the water-soluble release coating layer coated on the surface of the substrate layer, the printing layer forms a printing pattern on the surface of the water-soluble release coating layer, the protective layer is coated on the printing layer, the cold seal adhesive layer is coated on the other side of the substrate layer away from the water-soluble release coating layer, and the composite packaging film forms a composite structure. When recycled, the water-soluble release coating layer is dissolved, and the printing layer can be quickly separated from the substrate layer, which is beneficial to improve the problem that the traditional food packaging film is difficult to ensure the integrity of the material through mechanical peeling and that there is a large amount of residual printing layer after peeling, so that a separable composite packaging film is obtained, and the recycling rate of the food packaging film is improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 It is a sectional view of an environmental protection type separable composite packaging film of an embodiment of the present application.

[0020] Figure 2 It is a sectional view of an environmental protection type separable composite packaging film of an embodiment of the present application.

[0021] Figure 3 It is a sectional view of an environmental protection type separable composite packaging film of an embodiment of the present application.

[0022] Markings in the figure:

[0023] 1, protective layer; 2, printing layer; 3, water-soluble release coating; 4, substrate layer; 5, cold seal adhesive layer. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The described embodiments are part of the embodiments of the present application, rather than all the embodiments of the present application.

[0025] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of the present application.

[0026] Example 1:

[0027] Please refer to the drawings Figure 1 The environment-friendly separable composite packaging film of the present application can be applied to the packaging of leisure food, chocolate or biscuit, and the composite packaging film forms a composite multi-layer structure, has high recovery rate in recycling and processing, and is beneficial to saving resources and reducing environmental pollution.

[0028] The environment-friendly separable composite packaging film of the present application comprises, from outside to inside, a protective layer 1, a printing layer 2, a water-soluble release coating 3, a substrate layer 4 and a cold seal adhesive layer 5. The water-soluble release coating 3 is coated on the surface of the substrate layer 4, the dry film thickness of the water-soluble release coating 3 after curing is 0.5-1.2 μm, the printing layer 2 and the substrate layer 4 are compounded by the water-soluble release coating 3, the water-soluble release coating 3 ensures the bonding strength between the printing layer 2 and the substrate layer 4, and at the same time, is beneficial to the rapid separation of the printing layer 2 and the substrate layer 4 of the composite packaging film in recycling and processing, and improves the recovery rate.

[0029] In a preferred embodiment, the water-soluble release coating 3 is made of a mixture of polyvinyl alcohol and hydroxypropyl methyl cellulose, specifically, the mixing mass ratio of polyvinyl alcohol and hydroxypropyl methyl cellulose is (3-5):1, in the recycling process, the composite packaging film is soaked in an alkaline solution, specifically, the pH value of the alkaline solution is 8.5-9.5, the soaking time of the composite packaging film is 5-10 min, and the peeling strength of the water-soluble release coating 3 and the printing layer 2 is ≤0.5 N / 15 mm, such as 0.1 N / 15 mm, 0.3 N / 15 mm or 0.5 N / 15 mm, which is beneficial to the rapid separation of the printing layer 2 and the substrate layer 4, and the ink residue of the printing layer 2 is <0.3 mg / m².

[0030] The printing layer 2 and the substrate layer 4 are compounded through the water-soluble release coating layer 3, in the recycling process, the water-soluble release coating layer 3 can be dissolved by soaking in an alkaline solution, so that the printing layer 2 and the substrate layer 4 can be quickly separated, the operation is convenient, the problem that the substrate damage rate is greater than 25% caused by mechanical peeling of the traditional printing layer 2 and the inner layer can be improved, the material integrity of the substrate layer 4 in recycling can be improved, and the recycling rate of the composite packaging film can be improved, which is safe to use and environmentally friendly.

[0031] Embodiment 2:

[0032] The difference between the embodiment and the embodiment 1 is that, please refer to the attached Figure 1 The substrate layer 4 is one of synthetic paper, MOPP film, aluminized paper or kraft paper, the thickness of the substrate layer 4 is 28-120 μm, and the surface tension is greater than or equal to 38 mN / m.

[0033] The printing layer 2 is printed on the surface of the water-soluble release coating layer 3, in some specific embodiments, the printing layer 2 is a gravure ink layer, and the gravure ink layer can be formed into a pattern by water-based gravure ink printing, and then the protective layer 1 is coated on the surface of the printing layer 2.

[0034] In a preferred embodiment, the protective layer 1 is a water-based polyurethane-acrylate copolymer layer coated on the printing layer 2 by reverse gravure, and specifically, the solid content of the water-based polyurethane-acrylate copolymer layer is 8% during the coating process, the water-based polyurethane-acrylate copolymer layer is coated on the surface of the printing layer 2 by reverse gravure, and the coating amount of the water-based polyurethane-acrylate copolymer layer is 1.8-2.5 g / m2, in some specific embodiments, the thickness of the water-based polyurethane-acrylate copolymer layer after curing is 0.8-1.2 μm, the pencil hardness is greater than or equal to 3H, and the light transmittance is greater than or equal to 92%. The water-based polyurethane-acrylate copolymer layer can protect the surface of the printing layer 2 to improve the durability and aesthetics of the printing layer 2, and the chlorine content of the water-based polyurethane-acrylate copolymer layer is less than or equal to 0.01%, which can reduce the risk of pollution caused by chlorine migration and production cost.

[0035] The cold seal adhesive layer 5 is coated on the side of the substrate layer 4 away from the water-soluble release coating layer 3, in a preferred embodiment, the cold seal adhesive layer 5 is a styrene-isoprene-styrene-based hot melt adhesive layer, the thickness of the cold seal adhesive layer 5 is 2.5-4.0 μm and the coating amount is 3-5 g / m2. Specifically, the activation temperature of the cold seal adhesive layer 5 is 70-85℃, and the heat sealing strength with the substrate layer 4 is greater than or equal to 8 N / 15 mm, the cold seal adhesive layer 5 has good low-temperature adhesion, strong self-adhesion, and good sealing effect with the substrate layer, and at the same time, the cold seal adhesive layer 5 is in direct contact with food, which can ensure the quality and safety of food.

[0036] Embodiment 3:

[0037] The difference between this embodiment and embodiment 2 is that, please refer to the attached Figure 2 The substrate layer 4 of this embodiment can be a MOPP film with a thickness of 28 μm, and the surface of the substrate layer 4 can be subjected to a corona treatment to a surface tension of 40 mN / m, which is beneficial to the adhesion of the printing layer 2 and the water-soluble release coating 3.

[0038] The surface of the substrate layer 4 is coated with the water-soluble release coating 3 using a micro gravure coating, and the water-soluble release coating 3 is uniformly coated on the surface of the substrate layer 4 with a precisely controlled coating amount. Specifically, the mass ratio of polyvinyl alcohol and hydroxypropyl methyl cellulose in the water-soluble release coating 3 can be 4:1, the solid content is 8%, and the dry film thickness of the water-soluble release coating 3 after curing is 1.5 μm, and the drying and curing temperature is 55°C.

[0039] The printing layer 2 is printed on the surface of the water-soluble release coating 3, and the surface of the printing layer 2 is coated with a protective layer 1 after drying, and the coating amount of the protective layer 1 is 2.2 g / m². The cold seal adhesive layer 5 is coated on the side of the substrate layer 4 away from the water-soluble release coating 3, and the coating amount of the cold seal adhesive layer 5 is 4 g / m², and the heat seal strength of the cold seal adhesive layer 5 and the substrate layer 4 is 8.5 N / 15 mm, and the composite packaging film has good mechanical properties and barrier properties.

[0040] When the composite packaging film is recycled, it can be soaked in a sodium carbonate solution, the soaking time is 10 min, and the soaking temperature is 45-55°C. The water-soluble release coating 3 dissolves in the sodium carbonate solution, and the ink residue is 0.2 mg / m², the residual amount is small, and the recovery rate of the substrate layer 4 is high.

[0041] Example 4:

[0042] The difference between this embodiment and embodiment 3 is that, please refer to the attached Figure 2 The substrate layer 4 of this embodiment can be an aluminum-plated paper with a thickness of 28 μm, and the heat seal strength of the cold seal adhesive layer 5 and the substrate layer 4 is 7.5 N / 15 mm. When the composite packaging film is recycled, the ink residue is 0.25 mg / m², and the recovery rate of the substrate layer 4 is high.

[0043] Example 5:

[0044] The difference between this embodiment and embodiment 3 is that, please refer to the attached Figure 3 The substrate layer 4 of this embodiment can be a synthetic paper with a thickness of 28 μm, specifically, the synthetic paper is a PP synthetic paper, and the heat seal strength of the cold seal adhesive layer 5 and the substrate layer 4 is 9.2 N / 15 mm. When the composite packaging film is recycled, the ink residue is 0.15 mg / m², and the recovery rate of the substrate layer 4 is high.

[0045] In some specific embodiments, the water-soluble release coating layer 3 is provided with a micro-concave structure on the side close to the printing layer 2, the micro-concave structure can improve the bonding force of the printing layer 2, the protective layer 1 and the water-soluble release coating layer 3, and meanwhile, the printing layer 2 and the substrate layer 4 can still be quickly separated in the recycling process.

[0046] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing" and the like should be interpreted in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] In the description of the present application, it should be pointed out that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the present application is used, and is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a specific orientation, structure and operation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation, and cannot be understood as indicating or implying relative importance.

[0048] In addition, the terms "horizontal", "vertical", "overhanging" and the like do not mean that the components must be absolutely horizontal or overhanging, but can be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0049] In the present application, unless otherwise explicitly specified and limited, the first feature above or below the second feature can include that the first and second features are in direct contact, or can include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the first feature above, above and above the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The first feature below, below and below the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0050] Although the description of the utility model is combined with above specific embodiment, but, personnel familiar with this technical field can carry out many substitutions, modification and change according to the above content, it is obvious. Therefore, all such alternatives, improvements and changes are included in the spirit and scope of the appended claims.

Claims

1. An environment-friendly separable composite packaging film, characterized in that, The protective layer (1), the printing layer (2), the water-soluble release coating layer (3), the substrate layer (4) and the cold seal adhesive layer (5) are sequentially arranged from outside to inside, wherein the dry film thickness of the water-soluble release coating layer (3) after curing is 0.5-1.2 μm.

2. The environment-friendly separable composite packaging film according to claim 1, characterized in that, The peeling strength of the water-soluble release coating layer (3) in an alkaline solution from the printing layer (2) is ≤0.5 N / 15 mm.

3. The environment-friendly separable composite packaging film according to claim 1, characterized in that, The protective layer (1) is an aqueous polyurethane-acrylate copolymer layer which is reverse gravure coated on the printing layer (2).

4. The environment-friendly separable composite packaging film according to claim 3, characterized in that, The thickness of the aqueous polyurethane-acrylate copolymer layer is 0.8-1.2 μm.

5. The environment-friendly separable composite packaging film according to claim 1, characterized in that, The substrate layer (4) is one of synthetic paper, MOPP film, aluminum-plated paper or kraft paper.

6. The environment-friendly separable composite packaging film according to claim 5, characterized in that, The thickness of the substrate layer (4) is 28-120 μm.

7. The environment-friendly separable composite packaging film according to claim 1, characterized in that, The cold seal adhesive layer (5) is a styrene-isoprene-styrene-based hot melt adhesive layer.

8. The environment-friendly separable composite packaging film according to claim 7, characterized in that, The thickness of the cold seal adhesive layer (5) is 2.5-4.0 μm.

9. The environment-friendly separable composite packaging film according to claim 1, characterized in that, The printing layer (2) is a gravure ink layer.

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