Multifunctional practical cover film as well as preparation method and application thereof

Abstract

The invention relates to the field of materials and application, and particularly discloses a multifunctional practical cover film and a preparation method and application thereof. The multifunctional practical cover film comprises a corona layer, a filler layer and a heat sealing layer which are connected in sequence, wherein the heat sealing layer is made of ethylene-ethyl acrylate copolymer; in addition, the preparation method has the advantages that the preparation method is suitable for various plastic cups, the sealing performance is guaranteed after sealing, and the easy-to-open performance is achieved.

Description

Technical Field

[0001] This application relates to the fields of materials and applications, and more specifically, to a multifunctional practical cover film, its preparation method, and its application. Background Technology

[0002] In the field of packaging materials, lid film, as an important form of packaging, has undergone several stages of development as the variety of goods has increased and people's demands for packaging functions have diversified. From its initial simple protective function, it has evolved to now require not only excellent sealing performance but also multiple functions such as moisture protection and preservation. Lid film is widely used in various industries, including food, pharmaceuticals, and daily necessities, playing a crucial role in ensuring product quality and extending shelf life. Its development has driven the progress of the packaging industry, enhanced product market competitiveness, and provided consumers with higher-quality goods.

[0003] There are two common types of film covers. One type uses a single material, such as pure polyethylene film. This type of film is relatively simple to manufacture and has a low cost, and can be produced through processes such as blow molding or casting. The other type uses multi-layer composite films, which combine films with different properties using adhesives. For example, nylon film with barrier properties can be combined with polyethylene film with heat-sealing properties to achieve better packaging results. Some films also contain additives, such as antistatic agents and slip agents, to improve the surface properties of the film and facilitate packaging operations.

[0004] However, existing capping film technology has significant drawbacks. Single-material films have limited functionality and cannot meet the needs of multi-functional packaging. For example, pure polyethylene film has poor barrier properties and cannot effectively prevent oxygen and moisture from entering the packaging, affecting the product's shelf life. While multi-layer composite films offer improved functionality, the use of adhesives may pose hygiene and safety risks, and the lamination process is relatively complex and costly. At the same time, conventional capping films also have shortcomings in heat-sealing performance, making it difficult to achieve a firm and stable heat-sealing effect. Summary of the Invention

[0005] To be applicable to various plastic cups and to ensure both sealing and easy opening after sealing, this application provides a multifunctional practical lid film, its preparation method, and its application.

[0006] In the first aspect, this application provides a multifunctional practical cover film, which adopts the following technical solution: A multifunctional and practical cover film includes a corona layer, a filler layer and a heat-sealing layer connected in sequence, wherein the heat-sealing layer is made of ethylene-ethyl acrylate copolymer.

[0007] By adopting the above technical solution, the multifunctional practical lid film has a structure consisting of a corona layer, a filler layer, and a heat-sealing layer connected in sequence, allowing each layer to work synergistically. The corona layer can improve the adhesion performance of the lid film surface, which is beneficial for subsequent printing, lamination and other processing steps. The filler layer can provide mechanical strength and stability to the lid film. The heat-sealing layer is made of ethylene-ethyl acrylate copolymer, which has good heat-sealing performance. When heated, it can quickly bond to the container to form a reliable sealing structure, effectively preventing leakage of contents and entry of external substances, ensuring product quality and safety. At the same time, it also has a certain degree of flexibility and chemical corrosion resistance, making the lid film suitable for sealing the mouths of cups made of various materials.

[0008] Preferably, the filler layer comprises the following raw materials in parts by weight: 40-50 parts polyethylene, 0.95-1.12 parts strength modifier, and 0.67-0.84 parts tensile agent.

[0009] By adopting the above technical solution, the filler layer is based on polyethylene as the raw material, and a strength modifier is added. The strength modifier can significantly improve the overall strength of the filler layer, and the tensile agent can effectively improve the tensile performance of the filler layer, making the entire multifunctional practical cover film less prone to breakage and damage during use, thereby enhancing the practicality and durability of the cover film.

[0010] Preferably, the strength modifier comprises calcium carbonate particles and nano-kaolin in a mass ratio of (3-4):1.

[0011] By adopting the above technical solution, calcium carbonate particles and nano-kaolin are used as strength modifiers in the filler layer of a multifunctional practical cover membrane. Calcium carbonate particles have good filling and reinforcing properties, which can increase the rigidity and hardness of the cover membrane. Nano-kaolin has a large specific surface area and a special layered structure, which can work synergistically with calcium carbonate particles to further improve the strength, toughness and barrier properties of the cover membrane, effectively improving the overall quality and performance of the cover membrane.

[0012] Preferably, the tensile agent is modified polycaprolactone fiber, and the preparation method of the modified polycaprolactone fiber includes the following steps: mixing polycaprolactone chips with modified bamboo fiber, heating and melting at 100-120°C, and performing melt spinning to obtain modified polycaprolactone fiber.

[0013] By adopting the above technical solution, polycaprolactone chips are mixed with modified bamboo fibers, heated and melted, and then melt-spun to obtain modified polycaprolactone fibers. Polycaprolactone has good flexibility and processing performance, and modified bamboo fibers can further enhance the mechanical properties and tensile strength of modified polycaprolactone fibers, thereby effectively enhancing the tensile properties of multifunctional practical cap film, making the cap film less prone to breakage under tensile force, improving the durability and stability of the cap film, thus ensuring the reliability of the cap film in actual use and better meeting the needs of application scenarios such as injection molded cup sealing cap film.

[0014] Preferably, the mass ratio of polycaprolactone chips to modified bamboo fiber is (5.95-6.12):(0.32-0.45).

[0015] By adopting the above technical solution and controlling the mass ratio of polycaprolactone chips to modified bamboo fiber, the two can be better integrated in the subsequent melt spinning process. Polycaprolactone chips have good flexibility and processing performance, and the modified bamboo fiber, after special treatment, enhances its compatibility and bonding force with polycaprolactone chips. By compounding them at a specific mass ratio, the performance of the tensile agent can be effectively improved. After being applied to the filler layer, it can enhance the tensile performance of the filler layer, improve the overall strength and durability of the multifunctional practical cover film, and make it better able to withstand external pulling forces and less prone to damage in actual use.

[0016] Preferably, the method for preparing the modified bamboo fiber includes the following steps: drying bamboo fiber at 80-90℃ for 2 hours, then heating to 130-140℃ and drying for 4 hours, adding an aluminate coupling agent and reacting at 85-90℃ for 10-15 minutes, cooling, and obtaining the modified bamboo fiber.

[0017] By adopting the above technical solution, after the bamboo fiber is dried, the addition of an aluminate coupling agent can improve the surface properties of the bamboo fiber, enhance the compatibility and bonding force between the bamboo fiber and other materials, thereby improving the performance of the final modified polycaprolactone fiber, and thus enhancing the strength and tensile properties of the multifunctional practical cover film.

[0018] Secondly, this application provides a method for preparing a multifunctional practical cover film, which adopts the following technical solution: A method for preparing a multifunctional practical cover film includes the following steps: a filler layer and a heat-sealing layer are composited by hot pressing, and the filler layer is subjected to corona treatment to prepare a multifunctional practical cover film.

[0019] By adopting the above technical solution, the filler layer and the heat-sealing layer are composited by hot pressing. The hot pressing composite method can tightly bond the filler layer and the heat-sealing layer, enhance the connection strength and stability between the two layers, and ensure the overall structural integrity of the multifunctional and practical cover film. The filler layer is subjected to corona treatment, which can improve the surface roughness and surface energy of the filler layer, enhance its bonding force with other materials and printability, so that the cover film can better realize its multifunctional purpose. For example, when used as a sealing cover film for injection molded cups, it can better fit the injection molded cup and improve the practicality of the cover film.

[0020] Thirdly, this application provides an application of a multifunctional practical cover film, employing the following technical solution: A multifunctional and practical sealing film is applied to the sealing of injection molded cups, which can be made of PET, PLA, PP, PE, or coated paper.

[0021] By adopting the above technical solution, the multifunctional and practical cap film can be applied to the sealing cap film of injection molded cups. The heat-sealing layer is made of ethylene-ethyl acrylate copolymer, which gives the cap film good heat-sealing performance and can tightly adhere to the injection molded cup, which helps to ensure the sealing performance. The filler layer contains polyethylene, strength modifier and tensile agent, which effectively improves the strength and tensile performance of the cap film, and can better withstand external forces without easily breaking and causing leakage of contents. This cap film can be applied to injection molded cups of various materials, such as PET injection molded cups, PLA injection molded cups, PP injection molded cups, PE injection molded cups and coated paper cups. It has wide applicability and can meet the sealing needs of injection molded cups of different materials, ensuring the sealing and safety of the contents of the injection molded cup.

[0022] In summary, this application has the following beneficial effects: 1. Because the multifunctional practical cap film in this application has a structure of a corona layer, a filler layer and a heat-sealing layer connected in sequence, each layer works synergistically. The corona layer can improve the adhesion performance of the cap film surface, which is beneficial to subsequent printing, lamination and other processing steps. The filler layer can provide mechanical strength and stability to the cap film. The heat-sealing layer is made of ethylene-ethyl acrylate copolymer. Ethyl acrylate copolymer has good heat-sealing performance. When heated, it can quickly bond with the container to form a reliable sealing structure, effectively preventing leakage of contents and entry of external substances, ensuring the quality and safety of the product. At the same time, it also has a certain degree of flexibility and chemical corrosion resistance, making the cap film suitable for sealing the mouth of cups made of various materials.

[0023] 2. In this application, the filler layer is based on polyethylene and a strength modifier is added. The strength modifier can significantly improve the overall strength of the filler layer, and the tensile agent can effectively improve the tensile properties of the filler layer, making the entire multifunctional practical cover film less prone to breakage and damage during use, thereby enhancing the practicality and durability of the cover film.

[0024] 3. In this application, polycaprolactone chips are mixed with modified bamboo fibers, heated and melted, and then melt-spun to obtain modified polycaprolactone fibers. Polycaprolactone has good flexibility and processing performance, and modified bamboo fibers can further enhance the mechanical properties and tensile strength of modified polycaprolactone fibers, thereby effectively enhancing the tensile properties of multifunctional practical cap film, making the cap film less prone to breakage when subjected to tensile force, improving the durability and stability of the cap film, thus ensuring the reliability of the cap film in actual use and better meeting the needs of application scenarios such as injection molded cup sealing cap 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 1-6 Preparation Example 1 The method for preparing modified bamboo fiber includes the following steps: drying bamboo fiber at 80℃ for 2 hours, then heating to 130℃ and drying for 4 hours, adding 1.26 wt% of aluminate coupling agent of bamboo fiber and reacting at 85℃ for 15 minutes, cooling, and obtaining modified bamboo fiber.

[0027] The preparation method of modified polycaprolactone fiber includes the following steps: mixing polycaprolactone chips with modified bamboo fiber, heating and melting at 100°C, and performing melt spinning to obtain modified polycaprolactone fiber. The mass ratio of polycaprolactone chips to modified bamboo fiber is 5.95:0.32.

[0028] Preparation Example 2 The method for preparing modified bamboo fiber includes the following steps: drying bamboo fiber at 80-90℃ for 2 hours, then heating to 140℃ and drying for 4 hours, adding 1.53wt% of aluminate coupling agent by weight of bamboo fiber, reacting at 90℃ for 10 minutes, and cooling to obtain modified bamboo fiber.

[0029] The preparation method of modified polycaprolactone fiber includes the following steps: mixing polycaprolactone chips with modified bamboo fiber, heating and melting at 120°C, and performing melt spinning to obtain modified polycaprolactone fiber. The mass ratio of polycaprolactone chips to modified bamboo fiber is 5.95:0.45.

[0030] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that in Preparation Example 3, the mass ratio of polycaprolactone chips to modified bamboo fiber is 5.95:0.12.

[0031] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that in Preparation Example 4, the mass ratio of polycaprolactone chips to modified bamboo fiber is 5.95:0.87.

[0032] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that in Preparation Example 5, the amount of aluminate coupling agent added is 0.5 wt%.

[0033] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 1 is that in Preparation Example 6, the amount of aluminate coupling agent added is 3 wt%. Example

[0034] Example 1 A multifunctional practical cover film includes a corona layer, a filler layer, and a heat-sealing layer connected in sequence. The heat-sealing layer is made of ethylene-ethyl acrylate copolymer. The filler layer includes the following raw materials in parts by weight: 40 kg polyethylene, 0.95 kg strength modifier, and 0.67 kg tensile agent. The strength modifier includes calcium carbonate particles and nano-kaolin in a mass ratio of 3:1. The tensile agent is the tensile agent prepared in Preparation Example 1.

[0035] The preparation method of the above-mentioned multifunctional practical cover film includes the following steps: the filler layer and the heat-sealing layer are composited by hot pressing, and the filler layer is subjected to corona treatment to obtain the multifunctional practical cover film.

[0036] The above-mentioned multifunctional and practical lid film is applied to the sealing lid film of injection molded cups. The injection molded cups can be PET injection molded cups, PLA injection molded cups, PP injection molded cups, PE injection molded cups, or coated paper cups.

[0037] Example 2 A multifunctional practical cover film includes a corona layer, a filler layer, and a heat-sealing layer connected in sequence. The heat-sealing layer is made of ethylene-ethyl acrylate copolymer. The filler layer includes the following raw materials in parts by weight: 50 kg polyethylene, 1.12 kg strength modifier, and 0.84 kg tensile agent. The strength modifier includes calcium carbonate particles and nano-kaolin in a mass ratio of 4:1. The tensile agent is the tensile agent prepared in Preparation Example 2.

[0038] The preparation method of the above-mentioned multifunctional practical cover film includes the following steps: the filler layer and the heat-sealing layer are composited by hot pressing, and the filler layer is subjected to corona treatment to obtain the multifunctional practical cover film.

[0039] The above-mentioned multifunctional and practical lid film is applied to the sealing lid film of injection molded cups. The injection molded cups can be PET injection molded cups, PLA injection molded cups, PP injection molded cups, PE injection molded cups, or coated paper cups.

[0040] Example 3 The difference between Example 3 and Example 1 is that in Example 3, the mass ratio of calcium carbonate particles to nano-kaolin is 2:1.

[0041] Example 4 The difference between Example 4 and Example 1 is that in Example 4, the mass ratio of calcium carbonate particles to nano-kaolin is 5:1.

[0042] Example 5 The difference between Example 5 and Example 1 is that in Example 5, the tensile agent used is the tensile agent prepared in Preparation Example 3.

[0043] Example 6 The difference between Example 6 and Example 1 is that in Example 6, the tensile agent used is the tensile agent prepared in Preparation Example 4.

[0044] Example 7 The difference between Example 7 and Example 1 is that in Example 7, the tensile agent used is the tensile agent prepared in Preparation Example 5.

[0045] Example 8 The difference between Example 8 and Example 1 is that in Example 8, the tensile agent used is the tensile agent prepared in Preparation Example 6.

[0046] Example 9 The difference between Example 9 and Example 1 is that in Example 9, an equal amount of polycaprolactone fiber is used instead of the tensile agent.

[0047] The performance testing was conducted using the raw materials and methods described in Examples 1-9. Multifunctional practical cover films were prepared, and the tensile strength of the multifunctional practical cover films was tested. PET injection molded cups were used for sealing, and the heat sealing strength of the multifunctional practical cover films was tested. The results are recorded in Table 1.

[0048] Table 1 Performance Tests of Multifunctional Practical Cover Film Item Tensile strength / MPa Heat seal strength / (N / 15mm) Example 1 38.5 12.8 Example 2 40.2 13.5 Example 3 32.1 11.9 Example 4 34.8 12.2 Example 5 29.6 10.5 Example 6 31.2 11.1 Example 7 28.4 10.2 Example 8 30.1 10.8 Example 9 25.3 9.6 As can be seen from Table 1, Examples 1-2, and Example 9, the multifunctional practical cover film prepared in Examples 1-2 has high tensile strength and heat-sealing strength. The filler layer of the multifunctional practical cover film contains a strength modifier composed of calcium carbonate particles and nano-kaolin, and modified polycaprolactone fiber as a tensile agent. Calcium carbonate particles have good filling and reinforcing properties, which can increase the rigidity and hardness of the cover film. Nano-kaolin has a large specific surface area and a special layered structure, which can work synergistically with calcium carbonate particles to further improve the strength, toughness, and barrier properties of the cover film, effectively improving the overall quality and performance of the cover film. The modified polycaprolactone fiber has good tensile strength and mechanical properties. The addition of strength modifier and tensile agent makes the multifunctional practical cover film itself have good mechanical strength, making it less prone to cracking during sealing and tearing. The heat-sealing layer uses ethylene-ethyl acrylate copolymer, which has good heat-sealing performance and can quickly bond to the container when heated to form a reliable sealing structure, giving the multifunctional practical cover film strong heat-sealing strength and a wide range of applications.

[0049] Example 9 did not use modified polycaprolactone fiber, but used ordinary polycaprolactone fiber. Its tensile strength and heat-sealing strength were lower than those of Examples 1-2, indicating that the modified bamboo fiber has an enhancing effect on the mechanical properties of polycaprolactone fiber. In Example 9, no modified bamboo fiber was added, and its tensile strength and heat-sealing strength decreased.

[0050] Compared with Examples 1-2, the tensile strength of Examples 3-4 decreased. In the preparation of the modified polycaprolactone fiber used in Examples 3-4, the mass ratio of calcium carbonate particles and nano-kaolin was changed, indicating that there is a synergistic reinforcing effect between calcium carbonate particles and nano-kaolin. When the mass is changed, the synergistic reinforcing effect is reduced, thus resulting in a decrease in tensile strength.

[0051] Compared with Examples 1-2, the tensile strength of Examples 5-6 decreased. In the preparation of the modified polycaprolactone fiber used in Examples 5-6, the mass ratio of polycaprolactone chips to modified bamboo fiber was changed. In Example 5, the proportion of bamboo fiber was too low, and an effective fiber reinforcement network could not be formed. In Example 6, the proportion of bamboo fiber was too high, which easily led to fiber agglomeration and poor dispersibility, affecting its reinforcing effect in the cover film and causing a decrease in tensile properties.

[0052] Compared with Examples 1-2, the tensile strength of Examples 7-8 decreased. In the preparation of the modified polycaprolactone fiber used in Examples 7-8, the amount of aluminate coupling agent added was changed. In Example 7, the amount of coupling agent added was too low, the surface modification of bamboo fiber was insufficient, and the compatibility and dispersibility with polycaprolactone were poor, resulting in uneven dispersion of bamboo fiber and affecting the strength of the multifunctional cover film. In Example 8, the amount of coupling agent added was too high. Excessive coupling agent may have a plasticizing effect or affect the interfacial bonding, which will reduce the reinforcing effect of the fiber.

[0053] 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 multifunctional and practical cover film, characterized in that: It includes a corona layer, a filler layer and a heat-sealing layer connected in sequence, wherein the heat-sealing layer is made of ethylene-ethyl acrylate copolymer.

2. The multifunctional practical cover film according to claim 1, characterized in that: The filler layer comprises the following raw materials in parts by weight: 40-50 parts polyethylene, 0.95-1.12 parts strength modifier, and 0.67-0.84 parts tensile agent.

3. The multifunctional practical cover film according to claim 2, characterized in that: The strength modifier comprises calcium carbonate particles and nano-kaolin in a mass ratio of (3-4):

1.

4. The multifunctional practical cover film according to claim 2, characterized in that: The tensile agent is modified polycaprolactone fiber. The preparation method of the modified polycaprolactone fiber includes the following steps: mixing polycaprolactone chips with modified bamboo fiber, heating and melting at 100-120℃, and performing melt spinning to obtain modified polycaprolactone fiber.

5. A multifunctional practical cover film according to claim 4, characterized in that: The mass ratio of polycaprolactone chips to modified bamboo fiber is (5.95-6.12):(0.32-0.45).

6. The multifunctional practical cover film according to claim 4, characterized in that: The method for preparing the modified bamboo fiber includes the following steps: drying bamboo fiber at 80-90℃ for 2 hours, then heating to 130-140℃ and drying for 4 hours, adding an aluminate coupling agent and reacting at 85-90℃ for 10-15 minutes, cooling, and obtaining the modified bamboo fiber.

7. A method for preparing a multifunctional practical cover film according to any one of claims 1-6, characterized in that: Includes the following steps: The filler layer and heat-sealing layer are composited by hot pressing, and the filler layer is subjected to corona treatment to produce a multifunctional and practical cover film.

8. The application of a multifunctional practical cover film according to any one of claims 1-6, characterized in that: Sealing film for injection molded cups, which can be made of PET, PLA, PP, PE or coated paper.