Soft and hard film packaging film and production method thereof

Abstract

The invention relates to the field of materials and application, and particularly discloses a soft and hard film packaging film and a production method thereof. The soft and hard film packaging film comprises a soft film and a hard film, the soft film comprises a temperature-resistant polyethylene inner layer, an aluminum foil layer and a polyester layer which are connected in sequence, and the hard film comprises a breakable polyethylene inner layer, a polystyrene layer, an aluminum foil layer and a polyester outer layer which are connected in sequence; in addition, the preparation method has the advantage that the packaging film is not prone to deformation but easy to open.

Description

Technical Field

[0001] This application relates to the fields of materials and applications, and more specifically, to a flexible and rigid film packaging film and a method for producing the same. Background Technology

[0002] In the field of packaging materials, the development of packaging films plays a crucial role in the protection, storage, and transportation of products. With continuous industrial progress and the improvement of people's living standards, the performance requirements for packaging films are becoming increasingly diversified. Packaging films must not only possess basic physical protective functions, such as moisture protection, dust protection, and oxidation prevention, but also meet the specific needs of different products to adapt to various complex usage environments and market demands. In many industries such as food, pharmaceuticals, and electronics, suitable packaging films can effectively extend the shelf life of products, improve product quality stability, and reduce product losses during distribution, thereby bringing significant economic and social benefits to enterprises.

[0003] Currently, in the packaging industry, various methods are commonly used to achieve different properties in packaging films. One common approach is to use packaging films made of a single material, such as pure polyethylene film, which has a certain degree of flexibility and water resistance and is widely used for products with less stringent packaging requirements. Another approach is to use multi-layer composite films. However, these composite films have relatively simple structures, typically combining several common plastic layers, such as polyethylene and polypropylene layers, to enhance the strength and barrier properties of the packaging film. In addition, some packaging films incorporate functional additives, such as antioxidants and UV absorbers, to improve their antioxidant and UV resistance, making them suitable for products sensitive to light and oxidation.

[0004] However, existing packaging films have certain shortcomings. Single-material packaging films often cannot simultaneously meet multiple performance requirements, such as having both good flexibility and high strength and barrier properties. Conventional multi-layer composite films have simple structures, and their performance is limited when dealing with complex environments and special product needs, making it difficult to achieve ideal packaging effects and failing to meet the market's demand for high-performance packaging films. Summary of the Invention

[0005] In order to make the packaging film less prone to deformation but easy to open, this application provides a flexible and rigid film packaging film and its production method.

[0006] In a first aspect, this application provides a flexible and rigid film packaging film, which adopts the following technical solution: A flexible and rigid film packaging film includes a flexible film and a rigid film. The flexible film includes a heat-resistant polyethylene inner layer, an aluminum foil layer, and a polyester layer connected in sequence. The rigid film includes a breakable polyethylene inner layer, a polystyrene layer, an aluminum foil layer, and a polyester outer layer connected in sequence.

[0007] By adopting the above technical solutions, the heat-resistant polyethylene inner layer in the soft film of the flexible and rigid film packaging film provides good temperature resistance, the aluminum foil layer can block oxygen, water vapor and light, and the polyester layer can enhance the strength and stability of the soft film; the easily breakable polyethylene inner layer in the rigid film facilitates the breaking of the packaging film when needed, the polystyrene layer can increase the hardness and rigidity of the rigid film, making the rigid film easy to break and open during use; the polyester outer layer and aluminum foil layer also provide barrier effects, protecting the internal structure, so that the packaging film has a good sealing and loading effect on the contents; the soft film can effectively disperse the pressure of the contents on the packaging film; and the rigid film allows users to quickly open the packaging film, combining the storage and easy-to-open properties of the packaging film.

[0008] Preferably, the brittle polyethylene inner layer comprises the following raw materials in parts by weight: 85-95 parts polyethylene, 5-15 parts brittleness modifier, wherein the brittleness modifier is selected from at least one of polypropylene and polystyrene.

[0009] By adopting the above technical solution, polypropylene and polystyrene are added as brittle modifiers to the inner layer of fragile polyethylene, which can effectively change the physical properties of polyethylene and enhance its brittleness. When it is necessary to open the soft and hard film packaging, the brittle inner layer of fragile polyethylene is easier to break, making it easier for users to tear open the packaging and improving the ease of opening the packaging film. Without affecting the overall flexibility of the soft film, the hard film has the characteristic of being easy to open, meeting the user's needs for the ease of use of the packaging film.

[0010] Preferably, the heat-resistant polyethylene inner layer comprises the following raw materials in parts by weight: 60-80 parts linear low-density polyethylene and 20-40 parts metallocene polyethylene.

[0011] By adopting the above technical solution, the heat-resistant polyethylene inner layer uses linear low-density polyethylene and metallocene polyethylene as raw materials. Linear low-density polyethylene has good flexibility, impact resistance, and chemical corrosion resistance, which can provide a certain physical property basis for the heat-resistant polyethylene inner layer. Metallocene polyethylene has a narrower molecular weight distribution, a regular molecular chain structure, and high crystallinity, and has excellent tensile properties, tear resistance, and thermal stability. The combination of the two allows the heat-resistant polyethylene inner layer to have both the flexibility and impact resistance of linear low-density polyethylene and the high strength and good thermal stability of metallocene polyethylene, thereby improving the temperature resistance and physical strength of the entire soft and hard film packaging film. This allows it to better protect the contents of the package under different temperature environments, while also enhancing the durability of the packaging film during use and reducing the possibility of damage.

[0012] Preferably, the heat-resistant polyethylene inner layer further includes 5-8 parts of toughening agent, wherein the toughening agent comprises modified polycaprolactone fiber and high-density linear polyethylene fiber in a mass ratio of (1.25-1.64):(0.84-0.95).

[0013] By adopting the above technical solution, adding modified polycaprolactone fiber and high-density linear polyethylene fiber as toughening agents to the inner layer of heat-resistant polyethylene can significantly improve the toughness of the inner layer. Modified polycaprolactone fiber has good strength and stability, while high-density linear polyethylene fiber itself also has high toughness. The two are combined in a specific mass ratio to form a complex fiber network in the inner layer of heat-resistant polyethylene. This allows the inner layer of heat-resistant polyethylene to better disperse stress when subjected to external impact or tension, reducing the possibility of cracking and damage. As a result, the durability and reliability of the entire soft and hard film packaging film are enhanced, effectively protecting the items inside the packaging film.

[0014] Preferably, the method for preparing the modified polycaprolactone fiber includes the following steps: ultrasonically dispersing graphene uniformly in chloroform, adding polycaprolactone and shaking to form a uniform spinning solution, and obtaining the modified polycaprolactone fiber by electrospinning.

[0015] By adopting the above technical solution, modified polycaprolactone fiber is obtained by electrospinning, which has high mechanical properties and thermal stability. The addition of graphene can further improve the mechanical properties and thermal stability of modified polycaprolactone fiber, thereby effectively improving the toughness and comprehensive performance of the heat-resistant polyethylene inner layer, and thus improving the overall performance of soft and hard film packaging film.

[0016] Preferably, the amount of graphene added is 2.15-2.47 wt% of polycaprolactone.

[0017] By adopting the above technical solution and controlling the amount of graphene added, the graphene can be evenly dispersed in the spinning solution, thereby making the modified polycaprolactone fiber have a uniform texture and good mechanical properties and tensile strength.

[0018] Secondly, this application provides a method for producing flexible and rigid film packaging films, employing the following technical solution: A method for producing a flexible and rigid film packaging film includes the following steps: unwinding flexible film rolls and rigid film rolls separately; using a hot air knife to heat-seal three sides of the flexible and rigid films to form a three-sided sealed bag; filling the bag with contents; heat-sealing the fourth side; and using a laser or mechanical blade to process the rigid film, cutting the polyester outer layer to form scratches.

[0019] By adopting the above technical solution, three sides of the soft film and hard film are first heat-sealed to form a three-sided sealed bag, which facilitates the filling of contents. After the contents are filled into the bag, the fourth side is heat-sealed to complete the sealing of the entire bag, so that the contents are completely sealed inside the bag. Then, laser or mechanical blades are used to process the hard film, cutting the polyester outer layer to form scratches. These scratches can guide the user when it is necessary to open the packaging, making it easy for the user to tear open the hard film along the scratches and easily open the packaging film, thus improving the convenience of using the packaging film.

[0020] Preferably, the scratch depth is 50-90% of the thickness of the polyester outer layer.

[0021] By adopting the above technical solution and controlling the scratch depth, it is possible to ensure that when the packaging film needs to be opened, the polyester outer layer of the hard film can be easily torn open along the scratch, making it convenient to access the contents inside the bag; at the same time, the polyester outer layer will not easily break during normal transportation and storage due to excessively deep scratches, thereby ensuring the overall sealing and integrity of the packaging film and maintaining its protective function for the contents.

[0022] In summary, this application has the following beneficial effects: 1. In this application, the heat-resistant polyethylene inner layer in the soft film of the soft and hard film packaging film provides good temperature resistance, the aluminum foil layer can block oxygen, water vapor and light, and the polyester layer can enhance the strength and stability of the soft film; the easily breakable polyethylene inner layer in the hard film makes it easy to break the packaging film when needed, the polystyrene layer can increase the hardness and rigidity of the hard film, making it easy to break and open the packaging film during use; the polyester outer layer and the aluminum foil layer also have a barrier effect, which can protect the internal structure, so that the packaging film has a good sealing and loading effect on the contents. The soft film can effectively disperse the pressure of the contents on the packaging film, and the hard film allows users to quickly open the packaging film, combining the storage and easy-to-open properties of the packaging film.

[0023] 2. In this application, polypropylene and polystyrene are added to the inner layer of the fragile polyethylene as brittle modifiers, which can effectively change the physical properties of polyethylene and enhance its brittleness. When it is necessary to open the soft and hard film packaging, the brittle inner layer of the fragile polyethylene is easier to break, making it easier for users to tear open the packaging and improving the ease of opening the packaging film. Without affecting the overall flexibility of the soft film, the hard film has the characteristic of being easy to open, which meets the user's needs for the ease of use of the packaging film.

[0024] 3. In this application, modified polycaprolactone fiber and high-density linear polyethylene fiber are added as toughening agents to the inner layer of heat-resistant polyethylene, which can significantly improve the toughness of the inner layer of heat-resistant polyethylene. Modified polycaprolactone fiber has good strength and stability, and high-density linear polyethylene fiber itself also has high toughness. The two are combined in a specific mass ratio to form a complex fiber network in the inner layer of heat-resistant polyethylene. This allows the inner layer of heat-resistant polyethylene to better disperse stress when subjected to external impact or tension, reducing the possibility of cracking and damage, thereby enhancing the durability and reliability of the entire soft and hard film packaging film and effectively protecting the items inside the packaging film. Detailed Implementation

[0025] The present application will be further described in detail below with reference to the embodiments.

[0026] Preparation Examples of Modified Polycaprolactone Fibers 1-4 Preparation Example 1 The preparation method of modified polycaprolactone fiber includes the following steps: graphene is ultrasonically and uniformly dispersed in chloroform, polycaprolactone is added and shaken to form a homogeneous spinning solution of 0.15 g / mL, and modified polycaprolactone fiber is obtained by electrospinning. The spinning voltage is 28 kV, the spinning rate is 6 mL / h, the receiving distance is 35 cm, and the amount of graphene added is 2.15 wt% of polycaprolactone.

[0027] Preparation Example 2 The preparation method of modified polycaprolactone fiber includes the following steps: graphene is ultrasonically and uniformly dispersed in chloroform, polycaprolactone is added and shaken to form a homogeneous spinning solution of 0.18 g / mL, and modified polycaprolactone fiber is obtained by electrospinning. The spinning voltage is 25 kV, the spinning rate is 5 mL / h, the receiving distance is 30 cm, and the amount of graphene added is 2.47 wt% of polycaprolactone.

[0028] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that in Preparation Example 3, the amount of graphene added is 1.15 wt% of polycaprolactone.

[0029] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that in Preparation Example 4, the amount of graphene added is 3.65 wt% of polycaprolactone. Example

[0030] Example 1 A flexible and rigid film packaging film includes a flexible film and a rigid film. The flexible film includes a heat-resistant polyethylene inner layer, an aluminum foil layer, and a polyester layer connected in sequence. The heat-resistant polyethylene inner layer includes the following raw materials in parts by weight: 60 kg of linear low-density polyethylene and 20 kg of metallocene polyethylene. The rigid film comprises a broken polyethylene inner layer, a polystyrene layer, an aluminum foil layer, and a polyester outer layer connected in sequence. The broken polyethylene inner layer comprises the following raw materials in parts by weight: 85 kg polyethylene and 5 kg brittle modifier, wherein the brittle modifier is polypropylene. The above-mentioned production method of soft and hard film packaging film includes the following steps: unwinding soft film rolls and hard film rolls separately, using a hot air knife to heat seal three sides of the soft film and hard film to form a three-sided sealed bag, filling the bag with contents, and then heat sealing the fourth side, using a laser or mechanical blade to process the hard film, cutting the polyester outer layer to form scratches, with the scratch depth being 50% of the thickness of the polyester outer layer.

[0031] Example 2 A flexible and rigid film packaging film includes a flexible film and a rigid film. The flexible film includes a heat-resistant polyethylene inner layer, an aluminum foil layer, and a polyester layer connected in sequence. The heat-resistant polyethylene inner layer includes the following raw materials in parts by weight: 80 kg of linear low-density polyethylene and 40 kg of metallocene polyethylene. The rigid film comprises a breakable polyethylene inner layer, a polystyrene layer, an aluminum foil layer, and a polyester outer layer connected in sequence. The breakable polyethylene inner layer comprises the following raw materials in parts by weight: 95 kg polyethylene and 15 kg brittle modifier, wherein the brittle modifier is polystyrene. The production method of the above-mentioned soft and rigid film packaging film includes the following steps: unwinding the soft film roll and the rigid film roll separately, using a hot air knife to heat seal three sides of the soft film and the rigid film to form a three-sided sealed bag, filling the bag with contents, and then heat sealing the fourth side. The rigid film is processed using a laser or mechanical blade to cut and form scratches on the polyester outer layer, with the scratch depth being 90% of the thickness of the polyester outer layer.

[0032] Example 3 The difference between Example 3 and Example 1 is that in Example 3, the heat-resistant polyethylene inner layer also includes 5 kg of toughening agent. The toughening agent includes modified polycaprolactone fiber and high-density linear polyethylene fiber with a mass ratio of 1.25:0.84. The modified polycaprolactone fiber is the modified polycaprolactone fiber obtained in Preparation Example 1.

[0033] Example 4 The difference between Example 4 and Example 1 is that in Example 4, the heat-resistant polyethylene inner layer also includes 8 kg of toughening agent. The toughening agent includes modified polycaprolactone fiber and high-density linear polyethylene fiber with a mass ratio of 1.25:0.95. The modified polycaprolactone fiber is the modified polycaprolactone fiber obtained in Preparation Example 2.

[0034] Example 5 The difference between Example 5 and Example 3 is that in Example 5, the mass ratio of modified polycaprolactone fiber to high-density linear polyethylene fiber is 1.25:0.56.

[0035] Example 6 The difference between Example 6 and Example 3 is that in Example 6, the mass ratio of modified polycaprolactone fiber to high-density linear polyethylene fiber is 1.25:1.32.

[0036] Example 7 The difference between Example 7 and Example 3 is that in Example 7, the modified polycaprolactone fiber is the modified polycaprolactone fiber obtained in Preparation Example 3.

[0037] Example 8 The difference between Example 8 and Example 3 is that in Example 8, the modified polycaprolactone fiber is the modified polycaprolactone fiber obtained in Preparation Example 4.

[0038] Example 9 The difference between Example 9 and Example 1 is that no brittle modifier was added to the hard membrane in Example 9.

[0039] Example 10 The difference between Example 10 and Example 1 is that in Example 10, metallocene polyethylene was not added to the soft film.

[0040] Performance testing Following the raw materials and methods of Examples 1-10, soft and hard film packaging films were prepared. The elongation at break of the hard film and the tensile strength of the soft film were tested and recorded in Table 1.

[0041] Table 1 Performance Tests of Flexible and Rigid Film Packaging Films project Elongation at break / % Tensile strength / MPa Example 1 45 32 Example 2 48 35 Example 3 42 38 Example 4 40 40 Example 5 46 36 Example 6 44 37 Example 7 50 33 Example 8 52 31 Example 9 65 28 Example 10 55 30 As can be seen from Table 1, Examples 1-2, and Examples 9-10, the soft and hard film packaging films prepared in Examples 1-2 have different properties. The soft film has good tensile strength, enabling it to have good capacity and sealing performance, and is not prone to breakage and leakage. The hard film has a low elongation at break, making it easy to open during use. Thus, the soft and hard film packaging films simultaneously meet the requirements of being resistant to deformation, having good sealing and loading capacity, and being easy to open. The heat-resistant polyethylene inner layer in the soft film provides good temperature resistance, the aluminum foil layer acts as a barrier against oxygen, moisture, and light, and the polyester layer enhances the strength and stability of the soft film. The breakable polyethylene inner layer in the hard film facilitates breaking the packaging film when needed, and the polystyrene layer increases the hardness and rigidity of the hard film, making it easy to break and open during use, thus combining the storage and easy-to-open properties of the packaging film.

[0042] Compared with Examples 1-2, Examples 3-4 show a decrease in elongation at break and an increase in tensile strength. In Examples 3-4, a toughening agent was added to the inner layer of the heat-resistant polyethylene, indicating that the toughening agent can significantly improve the toughness of the inner layer of the heat-resistant polyethylene. The modified polycaprolactone fiber has good strength and stability, and the high-density linear polyethylene fiber itself also has high toughness. This allows the inner layer of the heat-resistant polyethylene to better disperse stress when subjected to external impact or tension, reducing the possibility of cracking and damage, thereby enhancing the durability and reliability of the entire soft and hard film packaging film.

[0043] Compared with Examples 3-4, Examples 5-6 showed an increased elongation at break and a decreased tensile strength. The mass ratio of modified polycaprolactone fiber to high-density linear polyethylene fiber was changed in Examples 5-6, indicating a synergistic effect between the modified polycaprolactone fiber and the high-density linear polyethylene fiber. The best reinforcement effect on the inner layer strength of the heat-resistant polyethylene was achieved when the mass ratio was changed.

[0044] Compared with Examples 3-4, Examples 7-8 showed an increased elongation at break and a decreased tensile strength. Examples 7-8 changed the amount of graphene added to the modified polycaprolactone fiber. Too little graphene added would weaken the reinforcing effect of graphene on polycaprolactone fiber, while too much graphene added would cause agglomeration, resulting in structural defects in the modified polycaprolactone fiber and thus affecting the overall performance of the soft and hard film packaging film.

[0045] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A soft and hard film packaging film, characterized by: The soft film comprises a temperature-resistant polyethylene inner layer, an aluminum foil layer and a polyester layer connected in sequence, and the hard film comprises a breakable polyethylene inner layer, a polystyrene layer, an aluminum foil layer and a polyester outer layer connected in sequence.

2. The soft and hard film packaging film according to claim 1, characterized in that: The breakable polyethylene inner layer comprises the following raw materials by weight: 85-95 parts of polyethylene, and 5-15 parts of a brittleness modifier selected from at least one of polypropylene and polystyrene.

3. The soft and hard film packaging film according to claim 1, characterized in that: The temperature-resistant polyethylene inner layer comprises the following raw materials by weight: 60-80 parts of linear low-density polyethylene, and 20-40 parts of metallocene polyethylene.

4. The soft and hard film packaging film according to claim 3, characterized in that: The temperature-resistant polyethylene inner layer further comprises 5-8 parts of a toughening agent comprising modified polycaprolactone fibers and high-density linear polyethylene fibers at a mass ratio of (1.25-1.64):(0.84-0.95).

5. The soft and hard film packaging film according to claim 4, characterized in that: The preparation method of the modified polycaprolactone fibers comprises the following steps: uniformly dispersing graphene in chloroform by ultrasonic, adding polycaprolactone and oscillating to form a uniform spinning solution, and preparing the modified polycaprolactone fibers by electrospinning.

6. A soft and hard film packaging film according to claim 5, characterized in that: The addition amount of the graphene is 2.15-2.47 wt% of the polycaprolactone.

7. A method of producing a soft and hard film packaging film according to any one of claims 1 to 6, characterized in that: The method comprises the following steps: The soft film and the hard film are heat-sealed by a hot air knife at three edges to form a bag body with three edges sealed, the fourth edge is heat-sealed after the bag body is filled with contents, and the polyester outer layer is cut to form a scratch by laser or a mechanical blade on the hard film.

8. The method of producing a soft and hard film packaging film according to claim 7, characterized by: The scratch depth is 50-90% of the thickness of the polyester outer layer.