Nylon film with self-repairing performance and preparation method thereof

Abstract

The invention discloses a nylon film with self-repairing performance and a preparation method thereof, and relates to a low-temperature efficient self-healing function realized by introducing a self-repairing network based on dynamic hydrogen bonds and deep eutectic sodium alginate microcapsules into a nylon matrix. The film which is good in transparency, excellent in flexibility and stable in mechanical property is prepared through a twin-screw extrusion and casting process, and microcracks can be rapidly repaired at the temperature ranging from room temperature to 60 DEG C. The method gives consideration to both film forming manufacturability and industrial feasibility, is suitable for the fields of packaging, electronics and the like, and has the advantages of high repairing efficiency, simple process and controllable cost.

Description

Technical Field

[0001] This invention belongs to the field of thin film technology, specifically relating to a nylon film with self-healing properties and its preparation method. Background Technology

[0002] Nylon is widely used in traditional packaging, electronic devices, and functional membrane materials due to its excellent mechanical properties, heat resistance, and film-forming properties. However, in actual use, nylon films are prone to micro-cracks or damage due to external forces, which affects their barrier properties, mechanical properties, and even service life. To extend the material's service life and improve its safety and functional stability, self-healing materials have become a key research focus.

[0003] Current research has attempted to introduce self-healing capabilities into polymer materials, primarily employing strategies such as microencapsulation, dynamic covalent bonding, and non-covalent interaction. Microencapsulation involves introducing microcapsules containing repair agents into the matrix, releasing the contents when the membrane is damaged to achieve repair. It offers advantages such as high repair efficiency and flexible design, but its compatibility and dispersibility are often limited, easily affecting membrane transparency and mechanical properties. Dynamic covalent bonding achieves repeated repair through reversible reactions, suitable for thermally responsive repair, but requires high reaction temperatures and complex processes, hindering industrialization. Non-covalent interaction constructs self-healing networks through physical interactions such as hydrogen bonding and metal coordination. It offers mild reaction conditions and strong adaptability, but the repair strength still needs improvement. For example,

[0004] Therefore, there is an urgent need for a nylon film material that is structurally simple, easy to process, has stable performance, high repair efficiency, and is suitable for melt processing, in order to achieve a balance between functionality and processability and meet the application requirements of high-performance film materials in packaging and other fields. Wanhua Chemical Group Co., Ltd. obtained furan-terminated nylon resin by adding furfurylamine as a capping agent during the nylon polymerization process through dynamic covalent bonds. The furan-terminated nylon resin was then reacted with a bismaleimide compound to obtain a self-healing nylon resin (CN117304479A). However, this method focuses more on the realization of self-healing function at the resin level and lacks systematic integration and optimization with the film formation process and the final film performance, which is not conducive to large-scale industrial promotion. Summary of the Invention

[0005] To address the problems of high repair temperature, complex processing, poor film-forming adaptability, and high cost of existing self-healing nylon materials, this invention provides a nylon film with self-healing properties and its preparation method. This film achieves low-temperature, high-efficiency self-healing of film cracks by introducing a self-healing network based on dynamic hydrogen bonding into the nylon matrix, combined with a deep eutectic sodium alginate capsule structure with reversible interactions, while maintaining both mechanical properties and processability. A self-healing nylon film with excellent flexibility, good transparency, and stable mechanical properties is prepared by melt extrusion casting using a twin-screw extruder. After being subjected to microcracks or mechanical damage, this film can achieve a rapid and efficient self-healing process at room temperature to 60°C by relying on the dynamic hydrogen bonding interaction between the releaseable repair components in the deep eutectic capsules and the nylon matrix. By introducing a deep eutectic capsule structure constructed from choline chloride, ethylene glycol, and sodium alginate, and by using maleic anhydride-grafted nylon to improve its dispersibility and interfacial bonding in the matrix, the membrane material is endowed with excellent repair capabilities and film-forming stability, overcoming the limitations of traditional self-healing materials such as complex processes and strong heat dependence.

[0006] The present invention provides a nylon membrane with self-healing properties, characterized in that, by weight, it comprises 91 to 96 parts of nylon particles, 3 to 6 parts of a deep eutectic solvent-sodium alginate microcapsule structure, and 0.5 to 2 parts of a compatibilizer.

[0007] The present invention provides a nylon membrane with self-healing properties, characterized in that the nylon is selected from one or more combinations of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 1212.

[0008] This invention provides a nylon membrane with self-healing properties. The membrane is characterized by a deep eutectic capsule structure constructed from a deep eutectic solvent, sodium alginate, prepared by an emulsification-spray drying method. The capsule has a particle size of 1-10 μm and is in the form of dense microspheres, which are uniformly dispersed in the nylon matrix. When the membrane is damaged, it can release the internal mobile phase and quickly fill the crack area by hydrogen bonding recombination and ion interaction.

[0009] This invention provides a nylon membrane with self-healing properties, characterized in that the compatibilizer is maleic anhydride-grafted nylon, which is used to enhance the dispersibility and interfacial compatibility of microcapsules in the nylon matrix, prevent phase separation, and improve the overall mechanical properties and membrane stability.

[0010] This invention provides a nylon membrane with self-healing properties, characterized in that after being subjected to microcrack damage, it can achieve a self-healing efficiency of over 90% within 30 minutes under a temperature condition of 40-60°C, making it suitable for fields such as packaging and electronics where material reliability and sustainability are highly demanding.

[0011] The method for preparing the self-healing nylon membrane includes the following steps:

[0012] (1) Mix different components of deep eutectic solvent at a molar ratio of 1:2 and stir to form a transparent and uniform deep eutectic solution; add sodium alginate to it and let it dissolve completely to form a viscous liquid. Then, use spray drying method to quickly dry at an inlet air temperature of 120-150℃ and an outlet air temperature of 60-80℃ to obtain deep eutectic sodium alginate microcapsules with a particle size of 1-10μm and a dense morphology for later use;

[0013] (2) Weigh 91-96 parts of nylon granules, 3-6 parts of the prepared deep eutectic sodium alginate microcapsules and 0.5-2 parts of maleic anhydride grafted nylon compatibilizer by weight, and dry mix them in a high-speed mixer for 3-5 minutes to ensure that each component is initially uniformly dispersed.

[0014] (3) The premixed material is fed into a twin-screw extruder and the temperature range is set to 180-230℃ (gradually increasing from the feed section to the die head). The screw speed is set to 40-80 rpm. Under the action of melt shearing, the deep eutectic capsules and nylon matrix are uniformly mixed. Then, the material is water-cooled, stretched, and pelletized to obtain functionalized self-healing nylon masterbatch.

[0015] (4) The obtained self-healing nylon masterbatch is fed into a casting extrusion equipment, and the temperature is controlled at 190-220℃, the cooling roller temperature at 50-60℃, and the winding speed at 6-10 m / min to cast a self-healing nylon film with a thickness of 40-70μm.

[0016] The preparation method described in this invention is simple and continuous, and the resulting membrane material has good flexibility and high transparency. It also has excellent low-temperature (room temperature to 60°C) self-healing properties and excellent mechanical strength, making it suitable for large-scale production and applications in multiple fields. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a deep eutectic sodium alginate microcapsule encapsulating a deep eutectic internal solution and nylon composite in Examples 1-4. Detailed Implementation

[0018] Example 1

[0019] This embodiment provides a nylon membrane with self-healing properties and its preparation method, as detailed below:

[0020] (1) Choline chloride and ethylene glycol were mixed evenly at a molar ratio of 1:2, and an appropriate amount of sodium alginate was added. The mixture was stirred and dissolved to form a transparent and uniform deep eutectic solution. The solution was then processed by emulsification-spray drying to prepare dense and uniform deep eutectic capsule powder with a particle size of about 3 μm.

[0021] (2) By weight, take 93 parts of nylon granules, 5 parts of choline chloride-ethylene glycol-sodium alginate deep eutectic microcapsules, and 1 part of maleic anhydride grafted nylon and premix them thoroughly in a high-speed mixer for 5 minutes to ensure initial uniform dispersion.

[0022] (3) The premixed material is fed into a twin-screw extruder, the temperature range is set to 190-220℃, the material is melt-extruded and water-cooled to form strips and pellets to obtain self-healing nylon masterbatch;

[0023] (4) The masterbatch is processed into a thin film with a thickness of approximately 40 μm by a casting process.

[0024] When a composite nylon membrane with microcracks is exposed to room temperature for 30 minutes, it can achieve a self-healing efficiency of over 85% and also exhibits good flexibility and transparency.

[0025] Example 2

[0026] This embodiment provides a nylon membrane with self-healing properties and its preparation method, as detailed below:

[0027] (1) Choline chloride and glycerol were mixed evenly at a molar ratio of 1:2, and an appropriate amount of sodium alginate was added. The mixture was stirred and dissolved to form a transparent and uniform deep eutectic solution. The solution was then processed by emulsification-spray drying to prepare dense and uniform deep eutectic capsule powder with a particle size of about 5 μm.

[0028] (2) By weight, take 93 parts of nylon granules, 5 parts of choline chloride-glycerol-sodium alginate deep eutectic microcapsules, and 1 part of maleic anhydride grafted nylon and premix them thoroughly in a high-speed mixer for 5 minutes to ensure initial uniform dispersion;

[0029] (3) The premixed material is fed into a twin-screw extruder, the temperature range is set to 190-220℃, the material is melt-extruded and water-cooled to form strips and pellets to obtain self-healing nylon masterbatch;

[0030] (4) The masterbatch is processed into a film with a thickness of about 50 μm by casting film process.

[0031] Heating a composite nylon membrane with microcracks at 40°C for 30 minutes can achieve a self-healing efficiency of over 90%, while also exhibiting good flexibility and transparency.

[0032] Example 3

[0033] This embodiment provides a nylon membrane with self-healing properties and its preparation method, as detailed below:

[0034] (1) Choline chloride and lactic acid were mixed evenly at a molar ratio of 1:2, and an appropriate amount of sodium alginate was added. The mixture was stirred and dissolved to form a transparent and uniform deep eutectic solution. The solution was then processed by emulsification-spray drying to prepare dense and uniform deep eutectic capsule powder with a particle size of about 7 μm.

[0035] (2) By weight, take 93 parts of nylon granules, 5 parts of choline chloride-lactic acid-sodium alginate deep eutectic microcapsules, and 1 part of maleic anhydride grafted nylon and premix them thoroughly in a high-speed mixer for 5 minutes to ensure initial uniform dispersion;

[0036] (3) The premixed material is fed into a twin-screw extruder, the temperature range is set to 190-220℃, the material is melt-extruded and water-cooled to form strips and pellets to obtain self-healing nylon masterbatch;

[0037] (4) The masterbatch is processed into a film with a thickness of about 60 μm by casting film process.

[0038] Heating a composite nylon membrane with microcracks at 50°C for 30 minutes can achieve a self-healing efficiency of over 92%, while also exhibiting good flexibility and transparency.

[0039] Example 4

[0040] This embodiment provides a nylon membrane with self-healing properties and its preparation method, as detailed below:

[0041] (1) Choline chloride and urea were mixed evenly at a molar ratio of 1:2, and an appropriate amount of sodium alginate was added. The mixture was stirred and dissolved to form a transparent and uniform deep eutectic solution. The solution was then processed by emulsification-spray drying to prepare dense and uniform deep eutectic capsule powder with a particle size of about 10 μm.

[0042] (2) By weight, take 93 parts of nylon granules, 5 parts of choline chloride-urea-sodium alginate deep eutectic microcapsules, and 1 part of maleic anhydride grafted nylon and premix them thoroughly in a high-speed mixer for 5 minutes to ensure initial uniform dispersion;

[0043] (3) The premixed material is fed into a twin-screw extruder, the temperature range is set to 190-220℃, the material is melt-extruded and water-cooled to form strips and pellets to obtain self-healing nylon masterbatch;

[0044] (4) The masterbatch is processed into a film with a thickness of about 70 μm by casting film process.

[0045] Heating a composite nylon membrane with microcracks at 60°C for 30 minutes can achieve a self-healing efficiency of over 95%, while also exhibiting good flexibility and transparency.

Claims

1. The nylon membrane with self-healing properties as described in claim 1, characterized in that, By weight, it comprises 91 to 96 parts of nylon particles, 3 to 6 parts of deep eutectic solvent-sodium alginate microcapsule structure, and 0.5 to 2 parts of compatibilizer.

2. The antibacterial nylon membrane with self-healing properties as described in claim 1, characterized in that, The nylon is selected from one or more combinations of nylon 6, nylon 66, nylon 610, nylon 12, and nylon 1212.

3. The nylon membrane with self-healing properties as described in claim 1, characterized in that, Deep eutectic capsules constructed from a deep eutectic solvent and sodium alginate were prepared by emulsification-spray drying. The particles, ranging from 1 to 10 μm in size, were dense microspheres that were uniformly dispersed in a nylon matrix. They could release the internal mobile phase when the membrane was damaged and quickly fill the cracked area by hydrogen bonding recombination and ion interactions.

4. The nylon membrane with self-healing properties as described in claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted nylon, which is used to enhance the dispersibility and interfacial compatibility of microcapsules in the nylon matrix, prevent phase separation, and improve the overall mechanical properties and membrane stability.

5. The nylon membrane with self-healing properties as described in claim 1, characterized in that, After being damaged by microcracks, it can achieve a self-healing efficiency of over 90% within 30 minutes under temperature conditions of 40-60℃, making it suitable for fields such as packaging and electronics where material reliability and sustainability are highly important.

6. The method for preparing the nylon membrane with self-healing properties as described in claim 1, characterized in that, Includes the following steps: (1) Mix different components of deep eutectic solvent at a molar ratio of 1:2 and stir to form a transparent and uniform deep eutectic solution; add sodium alginate to it and let it dissolve completely to form a viscous liquid. Then, use spray drying method to quickly dry at an inlet air temperature of 120-150℃ and an outlet air temperature of 60-80℃ to obtain deep eutectic sodium alginate microcapsules with a particle size of 1-10μm and a dense morphology for later use; (2) Weigh 91-96 parts of nylon granules, 3-6 parts of the prepared deep eutectic sodium alginate microcapsules and 0.5-2 parts of maleic anhydride grafted nylon compatibilizer by weight, and dry mix them in a high-speed mixer for 3-5 minutes to ensure that each component is initially uniformly dispersed. (3) The premixed material is fed into a twin-screw extruder and the temperature range is set to 180-230℃ (gradually increasing from the feed section to the die head). The screw speed is set to 40-80 rpm. Under the action of melt shearing, the deep eutectic capsules and nylon matrix are uniformly mixed. Then, the material is water-cooled, stretched, and pelletized to obtain functionalized self-healing nylon masterbatch. (4) The obtained self-healing nylon masterbatch is fed into a casting extrusion equipment, and the temperature is controlled at 190-220℃, the cooling roller temperature at 50-60℃, and the winding speed at 6-10 m / min to cast a self-healing nylon film with a thickness of 40-70μm.

Images