Super-hydrophobic polymer film prepared by chemical coupling enhanced hot pressing method as well as method and application of super-hydrophobic polymer film

Abstract

The invention provides a super-hydrophobic polymer film prepared by a chemical coupling enhanced hot pressing method and a method and application thereof, and belongs to the technical field of new materials and films. The method for preparing the super-hydrophobic polymer film by the chemical coupling enhanced hot pressing method comprises the following steps: uniformly mixing inorganic particles, an organic solvent, a coupling agent and a thermal initiator to obtain a coating; loading the coating on the surface of the polymer film, and airing to obtain the polymer film covered by inorganic particles; carrying out hot pressing on the polymer film covered by the inorganic particles to enable a part of the inorganic particles to be embedded into the polymer film, activating the thermal initiator, inducing the polymer film to be activated, and carrying out chemical coupling reaction on the activated polymer film and the inorganic particles through a coupling agent to obtain a chemical coupling enhanced polymer film; wherein under the condition that the inorganic particles are hydrophilic inorganic particles, the obtained chemical coupling enhanced polymer film or the hydrophilic inorganic particles in the chemical coupling enhanced polymer film are subjected to super-hydrophobic treatment.

Description

Technical Field

[0001] The present invention belongs to the fields of new materials and thin films, and particularly relates to a method for preparing a superhydrophobic polymer thin film by a chemically coupled enhanced hot pressing method, as well as the method and application thereof. Background Art

[0002] Superhydrophobic treatment of polymer thin films plays an important role in aspects such as waterproofing and anti-fouling, anti-corrosion, and reducing ice and snow adhesion, which helps to improve the durability and reliability of superhydrophobic polymer thin films. Coating superhydrophobic nanoparticles on the surface of polymers is a commonly used thin film superhydrophobic treatment solution at present, such as two means of chemical adhesion and physical adhesion. However, chemical adhesion is often limited by the interface size between superhydrophobic nanoparticles and polymer thin films, resulting in limited chemical bonds formed; physical adhesion is generally achieved by hot pressing, but often due to the certain flexibility of polymer thin films, they cannot resist external impacts and there is a problem of chipping, which affects the superhydrophobic performance of superhydrophobic thin films. Summary of the Invention

[0003] In view of the above problems, the present invention provides a superhydrophobic polymer thin film prepared by a chemically coupled enhanced hot pressing method, as well as the method and application thereof, in order to at least partially solve the above technical problems. For this, the technical solutions provided by the present invention are as follows.

[0004] As a first aspect of the present invention, there is provided a method for preparing a superhydrophobic polymer thin film by a chemically coupled enhanced hot pressing method, including: uniformly mixing inorganic particles, an organic solvent, a coupling agent, and a thermal initiator to obtain a coating, wherein the inorganic particles are superhydrophobic inorganic particles or hydrophilic inorganic particles; loading the coating onto the surface of a polymer thin film and drying it to obtain a polymer thin film covered with inorganic particles; performing hot pressing on the polymer thin film covered with inorganic particles to embed a part of the inorganic particles into the polymer thin film and activate the thermal initiator to induce activation of the polymer thin film, and the activated polymer thin film undergoes a chemical coupling reaction with the inorganic particles through the coupling agent to obtain a chemically coupled enhanced polymer thin film; wherein, in the case where the inorganic particles are hydrophilic inorganic particles, the obtained chemically coupled enhanced polymer thin film or the hydrophilic inorganic particles therein are subjected to superhydrophobic treatment.

[0005] As a second aspect of the present invention, there is provided a superhydrophobic polymer thin film prepared by a chemically coupled enhanced hot pressing method, including: a polymer thin film as a substrate, and inorganic particles partially embedded in the polymer thin film and chemically coupled to the polymer thin film; wherein the chemically coupled enhanced superhydrophobic polymer thin film is prepared by the method for preparing a superhydrophobic polymer thin film by the chemically coupled enhanced hot pressing method as described above.

[0006] As a third aspect of the present invention, there is provided an application of a superhydrophobic polymer thin film prepared by a chemically coupled enhanced hot pressing method in a packaging film or a waterproof rain gear.

[0007] Based on the above technical solutions, at least one of the following beneficial effects exists in the method for preparing a superhydrophobic polymer film by a chemically coupled enhanced hot pressing method and the application thereof provided by the present invention.

[0008] (1) The present invention hot presses a polymer film covered with inorganic particles. During the hot pressing process, the thermal initiator is activated by heat. The activated thermal initiator can induce the activation of the polymer film to generate free radicals. The coupling agent can react with the free radicals in the polymer chain segment and the groups on the surface of the inorganic particles simultaneously to form chemical bonds, thereby chemically coupling the inorganic particles with the activated polymer film through the coupling agent to achieve chemical adhesion. At the same time, during the hot pressing process, the polymer film is melted by heat, and a part of the inorganic particles can be embedded into the polymer film, increasing the interface area between the inorganic particles and the polymer film while achieving physical adhesion, facilitating more chemical coupling reactions to enhance chemical adhesion, and thus obtaining a chemically coupled enhanced polymer film. Among them, when the inorganic particles are hydrophilic inorganic particles, the obtained chemically coupled enhanced polymer film or the hydrophilic inorganic particles therein are subjected to superhydrophobic treatment to obtain a chemically coupled enhanced superhydrophobic polymer film; when the inorganic particles are superhydrophobic inorganic particles, the above method can directly obtain a chemically coupled enhanced superhydrophobic polymer film.

[0009] (2) The present invention combines physical and chemical dual adhesion effects with the hot pressing method to prepare a chemically coupled enhanced superhydrophobic polymer film with higher interfacial stability, wear resistance, and not easy to shed slag.

[0010] (3) Utilizing the good superhydrophobicity and wear resistance of the superhydrophobic polymer film, it can be applied to packaging films and rain gear to achieve the functions of waterproofing, antifouling, reducing ice and snow adhesion, and wear resistance. Description of the Drawings

[0011] Figure 1 It is a schematic flow chart of preparing a superhydrophobic polymer film by a chemically coupled enhanced hot pressing method in an embodiment of the present invention;

[0012] Figure 2 It is a schematic principle diagram of preparing a superhydrophobic polymer film by a chemically coupled enhanced hot pressing method in an embodiment of the present invention;

[0013] Figure 3 It is a schematic structural diagram of preparing a superhydrophobic polymer film by a chemically coupled enhanced hot pressing method in an embodiment of the present invention;

[0014] Figure 4 It is a contact angle diagram of a superhydrophobic polyethylene film in Example 1 of the present invention;

[0015] Figure 5 It is a hydrophobic stability test diagram of a superhydrophobic polyethylene film in Example 3 of the present invention;

[0016] Figure 6 Top view of the scanning electron microscope of the superhydrophobic polyethylene film in Example 4 of the present invention;

[0017] Figure 7 Side view of the scanning electron microscope of the superhydrophobic polyethylene film in Example 4 of the present invention;

[0018] Figure 8 Cross-sectional view of the scanning electron microscope of the superhydrophobic polyethylene film in Example 4 of the present invention;

[0019] Figure 9 Graph of the change in contact angle of the superhydrophobic polyethylene film under water flow impact in Examples 1, Comparative Example 1 - Comparative Example 2 of the present invention;

[0020] Figure 10 Scanning electron microscope (SEM) images of the superhydrophobic polyethylene film in Examples 1, Comparative Example 1 - Comparative Example 2 of the present invention after water flow impact, where a - b are SEM images of the superhydrophobic polyethylene film prepared by physical adhesion method at different magnifications, c - d are SEM images of the superhydrophobic polyethylene film prepared by chemical adhesion method at different magnifications, and e - f are SEM images of the superhydrophobic polyethylene film prepared by physical and chemical double adhesion method at different magnifications;

[0021] Figure 11 SEM image of the superhydrophobic polyethylene film in Example 1 of the present invention;

[0022] Figure 12 Graph of the change in contact angle of the superhydrophobic polyethylene film in Examples 1, Comparative Example 1 and Comparative Example 2 during the sand drop experiment;

[0023] Figure 13 Contact angle image of the superhydrophobic polyethylene film in Comparative Example 2;

[0024] Figure 14 Contact angle image of the superhydrophobic polyethylene film in Example 4 of the present invention.

[0025]

Description of the reference numerals

[0026] 1 - Superhydrophobic inorganic particles, 2 - Polymer film, 3 - Coupling agent. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further describes the present invention in detail with reference to specific embodiments.

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present invention. In the following detailed description, for the sake of explanation, numerous specific details are set forth in order to provide a comprehensive understanding of the embodiments of the present invention. However, it is obvious that one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present invention.

[0029] In the process of studying the thin-film superhydrophobic treatment, it is found that in the chemical adhesion method, the polymer film and the superhydrophobic inorganic particles are mainly chemically coupled through a coupling agent. However, this adhesion method requires that the polymer chain segments contain active groups (i.e., reactive groups) for the chemical coupling reaction. However, for polymer films without active groups, it is not applicable. In addition, the interface area between the superhydrophobic inorganic particles and the polymer film is small, and the chemical bonds formed by the chemical coupling reaction are limited, so there is still room for further improvement in the interfacial stability of chemical adhesion. In physical adhesion, taking advantage of the property that the polymer film is thermoplastified, a superhydrophobic polymer film can be prepared by a hot pressing method. Specifically, the polymer film is heated above its glass transition temperature by hot pressing to make it have a certain fluidity, and the superhydrophobic inorganic particles are pressed into the polymer film to form a surface with a micro-rough structure, thereby enhancing the hydrophobicity of the polymer film surface. However, due to the flexibility of the polymer film, the surface of the polymer film cannot resist the damage caused by external forces, resulting in the easy occurrence of chipping of the superhydrophobic inorganic particles, leading to the failure of its superhydrophobic performance.

[0030] In response to this, the present invention proposes to introduce a thermal initiator and a coupling agent between the inorganic particles and the polymer film before hot pressing. During the hot pressing process, the thermal initiator is activated by heat, and the activated thermal initiator activates the polymer film to generate free radicals. These free radicals can cause the inorganic particles to bond with the activated polymer film through a chemical coupling reaction via the coupling agent to form chemical bonds; at the same time, during the hot pressing process, the inorganic particles are embedded in the polymer film to form physical adhesion, increasing the interface area between the inorganic particles and the polymer film, thereby enhancing chemical adhesion, and thus obtaining a superhydrophobic polymer film with enhanced chemical coupling.

[0031] Figure 1 It is a schematic flow diagram of the preparation of a superhydrophobic polymer film by a hot pressing method with enhanced chemical coupling in an embodiment of the present invention.

[0032] As Figure 1 shown, the method for preparing a superhydrophobic polymer film by the hot pressing method with enhanced chemical coupling of the present invention includes: step S1 - step S3.

[0033] Step S1: Mix inorganic particles, an organic solvent, a coupling agent, and a thermal initiator uniformly to obtain a coating. The inorganic particles are superhydrophobic inorganic particles or hydrophilic inorganic particles.

[0034] Step S2: Load the coating onto the surface of the polymer film and dry it to obtain a polymer film covered with inorganic particles.

[0035] Step S3: Perform hot pressing on the polymer film covered with inorganic particles to embed a part of the inorganic particles into the polymer film and activate the thermal initiator to induce the activation of the polymer film. The activated polymer film undergoes a chemical coupling reaction with the inorganic particles through the coupling agent to obtain a chemically coupled enhanced polymer film. Wherein, when the inorganic particles are hydrophilic inorganic particles, perform superhydrophobic treatment on the obtained chemically coupled enhanced polymer film or the hydrophilic inorganic particles therein.

[0036] In the embodiments of the present invention, mixing inorganic particles, an organic solvent, a coupling agent, and a thermal initiator uniformly is beneficial to the uniform distribution of each component in the coating on the polymer film, thereby obtaining a polymer film with more excellent superhydrophobicity and wear resistance. Loading the coating onto the surface of the polymer film and drying it can remove the organic solvent (such as ethanol) in the coating to avoid danger during the hot pressing process. During the hot pressing process, the thermal initiator decomposes upon heating and simultaneously generates free radicals. The activated thermal initiator then induces the activation of the polymer film to generate free radicals. The coupling agent can react with the free radicals in the polymer chain segment and the groups on the surface of the inorganic particles simultaneously to form chemical bonds, thereby chemically coupling the inorganic particles with the activated polymer film through the coupling agent to achieve chemical adhesion. At the same time, the polymer film melts upon heating during the hot pressing process, and a part of the inorganic particles can be embedded into the polymer film, increasing the interface area between the inorganic particles and the polymer film while achieving physical adhesion, enabling more chemical coupling reactions to enhance chemical adhesion, thereby obtaining a chemically coupled enhanced superhydrophobic polymer film.

[0037] Specifically, in some embodiments, the method for preparing a superhydrophobic polymer film by a chemically coupled enhanced hot pressing method includes: mixing superhydrophobic inorganic particles, an organic solvent, a coupling agent, and a thermal initiator uniformly to obtain a superhydrophobic coating; loading the superhydrophobic coating onto the surface of the polymer film and drying it to obtain a polymer film covered with superhydrophobic inorganic particles; performing hot pressing on the polymer film covered with superhydrophobic inorganic particles to embed a part of the superhydrophobic inorganic particles into the polymer film and activate the thermal initiator to induce the activation of the polymer film. The activated polymer film undergoes a chemical coupling reaction with the superhydrophobic inorganic particles through the coupling agent to obtain a chemically coupled enhanced superhydrophobic polymer film.

[0038] In some embodiments, hydrophilic inorganic particles can also be superhydrophobically treated first and converted into superhydrophobic inorganic particles, and then the method provided in some of the above embodiments can be used to prepare a chemically coupled enhanced superhydrophobic polymer film.

[0039] In some embodiments, hydrophilic inorganic particles are used as raw materials, and the method of steps S1 - S3 in Figure 1 is used to prepare a chemically coupled enhanced superhydrophobic polymer film. Subsequently, the obtained chemically coupled enhanced superhydrophobic polymer film or the hydrophilic inorganic particles therein are superhydrophobically treated to obtain a chemically coupled enhanced superhydrophobic polymer film.

[0040] According to an embodiment of the present invention, the superhydrophobic treatment includes: superhydrophobically treating the hydrophilic inorganic particles or the chemically coupled enhanced polymer film with perfluorooctyltrichlorosilane. For example: putting the chemically coupled enhanced polyethylene film into a vacuum oven, adding 0.5 mL of perfluorooctyltrichlorosilane, and heating it under vacuum conditions at 60 °C for 8 hours to obtain a chemically coupled enhanced superhydrophobic polyethylene film.

[0041] According to an embodiment of the present invention, in step S1, mixing the inorganic particles, organic solvent, coupling agent, and thermal initiator uniformly to obtain a coating includes: mixing the inorganic particles with the organic solvent, and then adding the coupling agent and thermal initiator for mixing to obtain a coating, where the mixing method is ultrasonic mixing or mechanical stirring mixing, and the mixing time is 15 - 30 min. Both ultrasonic mixing and mechanical stirring mixing are to obtain a uniformly mixed coating, which is convenient for the subsequent uniform distribution of each component in the coating on the polymer film. The mass ratio of the inorganic particles, organic solvent, coupling agent, and thermal initiator is 450 - 550:15000 - 25000:95 - 105:0.9 - 1.1. If the proportion of the coupling agent is too low, the chemical adhesion effect will become poor, and if it is too high, the coating will become gelatinous, affecting the superhydrophobic effect. In some embodiments, mixing the superhydrophobic inorganic particles, organic solvent, coupling agent, and thermal initiator uniformly to obtain a superhydrophobic coating includes: mixing the superhydrophobic inorganic particles with the organic solvent, and then adding the coupling agent and thermal initiator for mixing to obtain a superhydrophobic coating, where the mass ratio of the superhydrophobic inorganic particles, organic solvent, coupling agent, and thermal initiator is 450 - 550:15000 - 25000:95 - 105:0.9 - 1.1.

[0042] According to an embodiment of the present invention, in step S1, the inorganic particles are selected from any one of metal oxides and non-metal oxides, wherein the metal oxides are selected from any one of silicon dioxide, titanium dioxide, aluminum oxide, and iron tetroxide, and the non-metal oxides are selected from ceramic particles. The surfaces of these inorganic particles all contain hydroxyl groups and can be coupled with the polymer film through a coupling agent. The inorganic particles in the present invention can be obtained by commercial purchase. For example, superhydrophobic inorganic particles can be directly purchased, or the purchased hydrophilic inorganic particles can be subjected to superhydrophobic treatment to be converted into superhydrophobic inorganic particles. Further, the particle size of the inorganic particles is 1 nm - 50 μm, and can be selected as 1 nm, 10 nm, 30 nm, 50 nm, 100 nm, 200 nm, 10 μm, 20 μm, 50 μm, etc. For example: the particle size of the superhydrophobic inorganic particles is 1 nm - 50 μm, and the particle size of the hydrophilic inorganic particles is 1 nm - 50 μm. The particle size of the inorganic particles (superhydrophobic inorganic particles or hydrophilic inorganic particles) should not be too large, otherwise the interfacial contact area between the inorganic particles and the polymer film is small and the effect of chemically coupling enhancement cannot be effectively achieved. Some of the hydroxyl groups on the surface of the inorganic particles undergo a chemical coupling reaction (such as a condensation reaction) with the coupling agent to connect the polymer film - coupling agent - inorganic particles, thereby realizing chemical adhesion between the inorganic particles and the polymer film.

[0043] According to an embodiment of the present invention, in step S1, the thermal initiator is a peroxide thermal initiator, selected from at least one of benzoyl peroxide, dicumyl peroxide, methyl isobutyl phenyl peroxide, dichloroacetic acid peroxide, and hydrogen peroxide. During the hot pressing process, the thermal initiator decomposes upon heating to generate thermal initiator monomer free radicals, which can activate the polymer film to form free radicals on the polymer film. The coupling agent is a silane coupling agent. Specifically, the silane coupling agent is selected from at least one of 3-(methacryloyloxy)propyltrimethoxysilane, aminopropyltrimethoxysilane, methyltrimethoxysilane, aminopropyltriethoxysilane, and glycidyletheroxypropyltrimethoxysilane. During the hot pressing process, the silane coupling agent hydrolyzes to form -Si-OH bonds, which can undergo dehydration condensation reactions with the hydroxyl groups (-OH) on the surface of the inorganic particles to achieve the connection between the silane coupling agent and the inorganic particles. At the same time, the silane coupling agent can also react with the free radicals in the polymer film segments to achieve the connection between the polymer film and the silane coupling agent, thereby using the coupling agent as a medium to connect the polymer film and the inorganic particles with different material properties, and thus obtaining a chemically coupled enhanced superhydrophobic polymer film with a stable interface, wear resistance, and not easy to shed inorganic particles. The organic solvent is selected from any one of C1-C3 alcohols and ethyl acetate, where the C1-C3 alcohols are any one of methanol, ethanol, propanol, and isopropanol. The organic solvent can contain a small amount of water, and the water content is less than 5 wt% of the organic solvent content. In other words, the water content is in the range of 0-5 wt% of the organic solvent content. Excessive water content will affect the hydrophobic performance of the polymer film.

[0044] According to an embodiment of the present invention, in step S2, the polymer film is selected from any one of polyethylene, polypropylene, polyvinyl chloride, polylactic acid, and cellulose.

[0045] According to an embodiment of the present invention, in step S2, loading the coating onto the surface of the polymer film includes: putting the polymer film into the coating and lifting the polymer film; or spraying the coating onto the surface of the polymer film; or spin-coating the coating onto the surface of the polymer film. For example, loading a superhydrophobic coating onto the surface of the polymer film includes: putting the polymer film into the superhydrophobic coating and lifting the polymer film; or spraying the superhydrophobic coating onto the surface of the polymer film; or spin-coating the superhydrophobic coating onto the surface of the polymer film. Specifically, taking the superhydrophobic coating prepared with superhydrophobic inorganic particles as raw materials as an example, for loading the superhydrophobic coating onto the surface of the polymer film by the lifting process, it includes: putting the polymer film into the superhydrophobic coating and uniformly lifting the polymer film with a moving shaft so that the superhydrophobic coating uniformly covers the polymer film, and then naturally drying it to obtain a polymer film covered with superhydrophobic inorganic particles. For loading the superhydrophobic coating onto the surface of the polymer film by the spraying process, it includes: uniformly spraying the superhydrophobic coating on the polymer film and then naturally drying it to obtain a polymer film covered with superhydrophobic inorganic particles. For loading the superhydrophobic coating onto the surface of the polymer film by the spin-coating process, it includes: fixing the polymer film on a spin coater and coating the superhydrophobic coating onto the polymer film during rotation so that the superhydrophobic coating is uniformly loaded on the polymer film, and then naturally drying it to obtain a polymer film covered with superhydrophobic inorganic particles. In the present invention, no matter which of the lifting, spraying, and spin-coating loading methods is adopted, it is to uniformly load the coating or the superhydrophobic coating onto the polymer film in order to obtain a superhydrophobic polymer film with excellent performance subsequently.

[0046] According to an embodiment of the present invention, in step S3, the hot pressing method is: flat hot pressing or roll-to-roll hot pressing, where the roll-to-roll hot pressing method is suitable for mass production and is convenient for industrialization. Further, the hot pressing temperature is 110 - 150 °C, for example, it can be 110 °C, 120 °C, 130 °C, 140 °C, 150 °C; the time is 1 - 10 s, for example, it can be 1 s, 4 s, 7 s, 10 s; the pressure is 30 - 60 kPa, for example, it can be 30 kPa, 40 kPa, 50 kPa, 60 kPa. The hot pressing conditions can be adjusted accordingly according to the properties of the polymer film in order to achieve better superhydrophobic performance.

[0047] Thus, the present invention prepares a chemically coupled enhanced superhydrophobic polymer film through a physical hot pressing method and a chemical coupling method, and simultaneously realizes double adhesion of physical adhesion and chemical adhesion, solving the problems that the contact area of a single chemical adhesion coupling interface is relatively small and / or limited by the active groups contained in the polymer film, and also solving the problems of poor durability and easy chipping of single physical adhesion.

[0048] Figure 2Schematic diagram of the principle for preparing superhydrophobic polymer film by chemically coupled enhanced hot pressing method in the embodiments of the present invention. Taking benzoyl peroxide as the thermal initiator, 3-(methacryloyloxy)propyltrimethoxysilane (MPS) as the coupling agent, silica (SiO2) as the superhydrophobic inorganic particles, and polyethylene (PE) as the polymer film as examples for illustration.

[0049] As Figure 2 shown, during the hot pressing process, the peroxide bond of benzoyl peroxide (thermal initiator) gradually breaks when heated to form thermal initiator monomer radicals (benzoic acid radicals). Subsequently, the benzoic acid radicals (i.e., activated thermal initiator) activate the polyethylene (PE) film to generate radicals in the polyethylene film. The radicals in the polyethylene chain segments can react with the coupling agent to connect the coupling agent to the polyethylene chain segments, forming polyethylene-coupling agent. During the hot pressing process, the coupling agent undergoes hydrolysis to form -Si-OH bonds, and these -Si-OH bonds can undergo a condensation reaction with the hydroxyl groups (-OH) on the surface of silica to form -Si-O-Si bonds, thereby realizing the coupling of the polyethylene film and silica through the coupling agent (MPS) to form polyethylene-coupling agent-silica.

[0050] As a second aspect of the present invention, there is provided a superhydrophobic polymer film prepared by a chemically coupled enhanced hot pressing method, including: a polymer film as a substrate, and inorganic particles partially embedded in the polymer film and chemically coupled with the polymer film; wherein, the superhydrophobic polymer film with chemically coupled enhancement is prepared by the method for preparing superhydrophobic polymer film by the above-mentioned chemically coupled enhanced hot pressing method.

[0051] Figure 3 For Figure 2 the schematic diagram of the structure of the superhydrophobic polymer film prepared by the chemically coupled enhanced hot pressing method in the present invention.

[0052] In the embodiments of the present invention, as Figure 3 shown, a part of the superhydrophobic inorganic particles 1 is embedded in the polymer film 2 to form physical adhesion, and chemical adhesion is realized through chemical coupling between the polymer film 2 and the superhydrophobic inorganic particles 1 by means of a coupling agent 3. Compared with traditional single chemical adhesion or physical adhesion, the superhydrophobic polymer film provided by the present invention has physical-chemical dual adhesion, which can significantly improve the superhydrophobicity, durability and wear resistance of the superhydrophobic polymer film.

[0053] According to an embodiment of the present invention, the contact angle of the chemically coupled enhanced superhydrophobic polymer film of the present invention is 150°-166°, indicating that the superhydrophobic polymer film has good superhydrophobic performance; the depth of the inorganic particles embedded in the polymer film is 5%-95% of the diameter of the inorganic particles, achieving good physical adhesion, increasing the chemical coupling interface, and enhancing the chemical coupling effect. In some embodiments, the depth of the superhydrophobic inorganic particles embedded in the polymer film is 5%-95% of the diameter of the superhydrophobic inorganic particles.

[0054] As the third aspect of the present invention, there is provided an application of a chemically coupled enhanced superhydrophobic polymer film prepared by a hot pressing method in a packaging film or a waterproof rain gear.

[0055] In an embodiment of the present invention, the chemically coupled enhanced superhydrophobic polymer film has excellent superhydrophobic performance and wear resistance, and can be applied in a packaging film or a waterproof rain gear, which can improve the abilities of waterproofing, anti-fouling, anti-corrosion, and reducing ice and snow adhesion, and increase the durability and reliability of the product.

[0056] The following will describe in detail the chemically coupled enhanced superhydrophobic polymer film prepared by a hot pressing method, its method and application of the present invention in combination with specific embodiments and drawings.

[0057] Example 1

[0058] The process of preparing a chemically coupled enhanced superhydrophobic polyethylene film by a hot pressing method is as follows in steps (1)-(3).

[0059] Step (1) Prepare a superhydrophobic coating: Add 30 g of superhydrophobic silica nanoparticles (20-50 nm, model AEROSIL® R 202) to 1000 mL of absolute ethanol, then add 10 g of 3-(methacryloyloxy)propyltrimethoxysilane and 0.2 g of benzoyl peroxide, mix and shake well to dissolve, and then ultrasonically disperse for 15 min with a cell crusher to obtain a superhydrophobic nano-silica coating.

[0060] Step (2) Prepare a polyethylene film covered with superhydrophobic silica nanoparticles: Cut the polyethylene film to the appropriate size. Subsequently, place the polyethylene film in the superhydrophobic nano-silica coating of step (1), and use a moving shaft to uniformly lift the polyethylene film at a constant speed of 10 mm / s to make the superhydrophobic nano-silica coating evenly cover the polyethylene film. After lifting, let it dry naturally to obtain a polyethylene film covered with superhydrophobic silica nanoparticles.

[0061] Step (3) Preparation of superhydrophobic polyethylene film by hot pressing method: Set the parameters of the flat hot press, i.e., the heating temperature is 130 °C, the pressure is 40 kPa, and the pressure holding time is 6 s; After setting, hot press the polyethylene film covered with superhydrophobic silica nanoparticles to obtain a chemically coupled enhanced superhydrophobic polyethylene film.

[0062] Measure the contact angle of the superhydrophobic polyethylene film in Example 1 with a contact angle measuring instrument. The specific measurement results are as Figure 4 shown.

[0063] Figure 4 This is the contact angle diagram of the superhydrophobic polyethylene film in Example 1 of the present invention.

[0064] As Figure 4 shown, the contact angle of the superhydrophobic polyethylene film in Example 1 is 164 ± 1.5 °.

[0065] Example 2

[0066] The process of preparing a superhydrophobic polyethylene film by chemically coupled enhanced hot pressing method is as follows: Step (1) - Step (3).

[0067] Step (1) Preparation of superhydrophobic coating: Add 30 g of superhydrophobic silica nanoparticles (20 - 50 nm, model AEROSIL® R 202) to 1000 mL of absolute ethanol, then add 10 g of 3-(methacryloyloxy)propyltrimethoxysilane and 0.2 g of benzoyl peroxide, mix and shake well to dissolve. Subsequently, ultrasonically disperse for 15 min with a cell crusher to obtain a superhydrophobic nano-silica coating.

[0068] Step (2) Preparation of a polyethylene film covered with superhydrophobic silica nanoparticles: Take out the polyethylene film and cut it to the appropriate size. Subsequently, place the polyethylene film in the superhydrophobic nano-silica coating in Step (1), and use a moving axis to uniformly lift the polyethylene film so that the superhydrophobic nano-silica coating evenly covers the polyethylene film. The lifting speed is 10 mm / s. After lifting, let it dry naturally to obtain a polyethylene film covered with superhydrophobic silica nanoparticles.

[0069] Step (3) Preparation of superhydrophobic polyethylene film by hot pressing method: Set the parameters of the roll-to-roll hot press, i.e., the heating temperature is 120 °C, adjust the distance between the two rolls to 0.1 mm, and the rotation speed is 10 mm / s; After setting, hot press the polyethylene film covered with superhydrophobic silica nanoparticles to obtain a chemically coupled enhanced superhydrophobic polyethylene film.

[0070] Measure the contact angle of the superhydrophobic polyethylene film in Example 2 with a contact angle measuring instrument. The measured contact angle of the superhydrophobic polyethylene film is 158 ± 3.2 °.

[0071] Example 3

[0072] The process of preparing a superhydrophobic polyethylene film by chemically coupled enhanced hot pressing is as follows in steps (1)-(3).

[0073] Step (1) Prepare a superhydrophobic coating: Add 35 g of superhydrophobic silica nanoparticles (20 - 50 nm) to 1000 mL of absolute ethanol, then add 10 g of 3-(methacryloyloxy)propyltrimethoxysilane and 0.2 g of benzoyl peroxide, mix and shake well to dissolve them mutually. Subsequently, ultrasonically disperse for 15 min using a cell disruptor to obtain a superhydrophobic nano-silica coating.

[0074] Step (2) Prepare a polymer film covered with superhydrophobic nano-silica nanoparticles: Take out the polyethylene film and cut it to the appropriate size. Subsequently, place the polyethylene film in the superhydrophobic nano-silica coating of step (1), adjust the moving axis to the appropriate position, and use the moving axis to uniformly lift the polyethylene film at a constant speed of 10 mm / s so that the superhydrophobic nano-silica coating uniformly covers the polyethylene film. After lifting, let it dry naturally to obtain a polyethylene film covered with superhydrophobic silica nanoparticles.

[0075] Step (3) Prepare a superhydrophobic polyethylene film by hot pressing: Set the parameters of the flat hot press, i.e., the heating temperature is 120 °C, the pressure is 50 kPa, and the pressure holding time is 8 s; after setting, perform hot pressing on the polyethylene film covered with superhydrophobic silica nanoparticles to obtain a chemically coupled enhanced superhydrophobic polyethylene film.

[0076] Measure the contact angle of the superhydrophobic polyethylene film in Example 3 using a contact angle measuring instrument. It is measured that the contact angle of this superhydrophobic polyethylene film is 155 ± 1.6°.

[0077] Furthermore, put the superhydrophobic polyethylene (PE) film prepared in Example 3 into ethanol and clean it in an ultrasonic cleaner (the cleaning power is 240 W). Measure the contact angle of the superhydrophobic polyethylene film every 1 h and replace the ethanol solvent. The experimental data of the contact angle of the superhydrophobic polyethylene film measured continuously for 6 h are as Figure 5 shown.

[0078] Figure 5 This is the test chart of the hydrophobic stability of the superhydrophobic polyethylene film in Example 3 of the present invention.

[0079] As Figure 5 shown, only a small amount of the contact angle of the superhydrophobic polyethylene film is relatively low, but generally it remains in a superhydrophobic state above 150°, indicating that the superhydrophobic polymer film in the present invention has excellent stability.

[0080] Example 4

[0081] The process of preparing superhydrophobic polyethylene film by chemically coupled enhanced hot pressing method is as follows: steps (1)-(3).

[0082] Step (1) Preparation of micron silica coating: Add 20 g of hydrophilic silica (10 μm) to 50 mL of anhydrous ethanol, then add 1 g of 3-(methacryloyloxy)propyltrimethoxysilane and 0.01 g of benzoyl peroxide, mix and shake well to dissolve them mutually. Subsequently, ultrasonically disperse for 15 min with a cell crusher to obtain the micron silica coating.

[0083] Step (2) Preparation of polymer film covered with micron silica particles: Take out the polyethylene film and cut it to the appropriate size. Subsequently, place the polyethylene film in the micron silica coating of step (1), adjust the moving axis to the appropriate position, and use the moving axis to uniformly lift the polyethylene film at a speed of 10 mm / s to make the micron silica coating uniformly cover the polyethylene film. After lifting, let it dry naturally to obtain the polyethylene film covered with micron silica particles.

[0084] Step (3) Preparation of chemically coupled enhanced polyethylene film by hot pressing method: Set the parameters of the flat hot press, that is, the heating temperature is 120 °C, the pressure is 50 kPa, and the pressure holding time is 20 s; after setting, perform hot pressing on the polyethylene film covered with micron silica particles to obtain the chemically coupled enhanced polyethylene film.

[0085] Step (4) Superhydrophobic modification of the polyethylene film: Put the chemically coupled enhanced polyethylene film obtained in step (3) into a vacuum oven, add 0.5 mL of perfluorooctyltrichlorosilane, and heat it under vacuum conditions at 60 °C for 8 hours to obtain the chemically coupled enhanced superhydrophobic polyethylene film.

[0086] Measure the contact angle of the superhydrophobic polyethylene film in Example 4 with a contact angle measuring instrument, and the measured contact angle of the superhydrophobic polyethylene film is 151.8 ± 1.0° (as Figure 14 shown).

[0087] Figure 6 This is the top view of the scanning electron microscope of the superhydrophobic polyethylene film in Example 4 of the present invention, Figure 7 This is the side view of the scanning electron microscope of the superhydrophobic polyethylene film in Example 4 of the present invention, Figure 8 This is the cross-sectional view of the scanning electron microscope of the superhydrophobic polyethylene film in Example 4 of the present invention.

[0088] As Figures 6 - 8As shown in the figure, a part of the silica micron particles in the present invention are embedded in the polyethylene film, and there is both physical and chemical adhesion, avoiding the situation of slag falling due to the shedding of silica micron particles in the superhydrophobic polyethylene film. Further, from Figures 6 - 8 it can also be seen that the depth of the silica micron particles embedded in the polyethylene film is 5% - 95% of the diameter of the silica micron particles.

[0089] Comparative Example 1

[0090] The process of preparing the superhydrophobic polyethylene film by physical adhesion method is as follows:

[0091] Step (1) Prepare the superhydrophobic nano-silica coating: Add 30 g of superhydrophobic silica nanoparticles (20 - 50 nm) to 1000 mL of absolute ethanol and disperse them with an ultrasonic cell disruptor for 15 min.

[0092] Step (2) Prepare the polyethylene film covered with superhydrophobic silica nanoparticles: Cut the polyethylene film to the appropriate size. Subsequently, place the polyethylene film in the superhydrophobic nano-silica coating prepared in step (1), and use a moving axis to uniformly lift the polyethylene film to make the superhydrophobic nano-silica coating evenly cover the polyethylene film, where the lifting speed is 10 mm / s. After the lifting is completed, let it dry naturally to obtain the polyethylene film covered with superhydrophobic silica nanoparticles.

[0093] Step (3) Prepare the superhydrophobic polyethylene film by hot pressing method: Set the parameters of the flat hot press, that is, the heating temperature is 130 °C, the pressure is 40 kPa, and the pressure holding time is 6 s; After setting, perform hot pressing on the polyethylene film covered with superhydrophobic silica nanoparticles obtained in step (2) to obtain the superhydrophobic polyethylene film prepared by the physical adhesion method.

[0094] Comparative Example 2

[0095] The process of preparing the superhydrophobic polyethylene film by only chemical adhesion method is as follows:

[0096] Step (1) Prepare the superhydrophobic nano-silica coating: Add 30 g of superhydrophobic silica nanoparticles (20 - 50 nm) to 1000 mL of absolute ethanol, then add 10 g of 3-(methacryloyloxy)propyltrimethoxysilane, 0.2 g of benzoyl peroxide (BPO), and benzophenone, mix and shake well to dissolve it. Subsequently, ultrasonically disperse it with a cell disruptor for 15 min to obtain the superhydrophobic nano-silica coating, where BPO is used to form free radicals, the free radicals are transferred to benzophenone, and benzophenone binds to the hydrogen on the polyethylene surface, and then free radicals are formed on the polyethylene surface.

[0097] Step (2) Preparation of superhydrophobic silica nanoparticle-coated polyethylene film: Cut the polyethylene film into appropriate sizes. Subsequently, place the polyethylene film in the superhydrophobic nano-silica coating of step (1), and use a moving axis to uniformly lift the polyethylene film at a constant speed of 10 mm / s so that the superhydrophobic nano-silica coating uniformly covers the polyethylene film. After lifting, let it dry naturally to obtain the superhydrophobic silica nanoparticle-coated polyethylene film.

[0098] Step (3) Preparation of superhydrophobic polyethylene film: Put the superhydrophobic silica nanoparticle-coated polyethylene film obtained in step (2) into an oven and heat it at 90 °C for 20 min to obtain the superhydrophobic polyethylene film prepared by chemical adhesion method.

[0099] Measure the contact angle of the superhydrophobic polyethylene film in Comparative Example 2 with a contact angle measuring instrument, and the measured contact angle of the superhydrophobic polyethylene film is 166 ± 0.0° (as Figure 13 )

[0100] Furthermore, according to the water flow scouring experiment in the national standard GB / T45017-2024, set up a water flow scouring experiment device, and conduct scouring experiments (scouring time is 50 min) on the superhydrophobic polyethylene film prepared by chemical adhesion (Comparative Example 2), the superhydrophobic polyethylene film prepared by physical adhesion (Comparative Example 1), and the superhydrophobic polyethylene film prepared by physical and chemical double adhesion (Example 1) to explore the change of the contact angle on the surface of the superhydrophobic polyethylene film under the water flow impact for the same time. The specific test results are as Figure 9 shown.

[0101] Figure 9 This is the contact angle change diagram of the superhydrophobic polyethylene film in Example 1, Comparative Example 1 - Comparative Example 2 in the embodiments of the present invention under water flow impact.

[0102] As Figure 9As shown in the figure, the contact angles of superhydrophobic polyethylene films prepared by different methods at time 0 (Example 1, Comparative Example 1 - Comparative Example 2) are basically the same. However, as the water flow scouring time increases, the contact angle of the superhydrophobic polyethylene film prepared by the physical adhesion method (Comparative Example 1) and the superhydrophobic polyethylene film prepared by the chemical adhesion method (Comparative Example 2) decreases sharply, while the contact angle of the superhydrophobic polyethylene film prepared by the physical and chemical double adhesion method (Example 1) remains basically unchanged. When the water flow impact time is about 14 minutes, the contact angles of the superhydrophobic polyethylene film prepared by the physical adhesion method (Comparative Example 1) and the superhydrophobic polyethylene film prepared by the chemical adhesion method (Comparative Example 2) are less than 150°. However, the contact angle of the superhydrophobic polyethylene film with physical and chemical double adhesion in Example 1 still remains at about 160°. When the scouring time reaches 40 minutes, the superhydrophobic polyethylene film prepared by the physical adhesion method in Comparative Example 1 and the superhydrophobic polyethylene film prepared by the chemical adhesion method in Comparative Example 2 have completely lost their superhydrophobic properties. On the contrary, the contact angle of the superhydrophobic polyethylene film with physical and chemical double adhesion in Example 1 still remains at about 150°. This shows that the superhydrophobic polyethylene film prepared by the present invention has high stability and wear resistance.

[0103] Furthermore, the morphologies of the three films in the above Example 1, Comparative Example 1 - Comparative Example 2 were observed, and the specific test results are as Figure 10 shown.

[0104] Figure 10 This is the scanning electron microscope (SEM) image of the superhydrophobic polyethylene films in Example 1, Comparative Example 1 - Comparative Example 2 of the present invention after being impacted by water flow. Among them, a - b are the SEM images of the superhydrophobic polyethylene film prepared by the physical adhesion method at different magnifications, c - d are the SEM images of the superhydrophobic polyethylene film prepared by the chemical adhesion method at different magnifications, e - f are the SEM images of the superhydrophobic polyethylene film prepared by the physical and chemical double adhesion method at different magnifications, and the part inside the box is the part impacted by the water flow; Figure 11 This is the SEM image of the superhydrophobic polyethylene film in Example 1 of the present invention.

[0105] As Figure 10 shown, it can be seen from the SEM image that by comparing the impacted part with the impacted edge, after the superhydrophobic polyethylene film prepared by the physical adhesion method in Comparative Example 1 and the superhydrophobic polyethylene film prepared by the chemical adhesion method in Comparative Example 2 are scoured by water flow for a long time of 50 minutes, the silica nanoparticles on the surface are basically scoured away, but the silica nanoparticles on the surface of the superhydrophobic film with physical and chemical double adhesion in Example 1 are basically not scoured away (as Figure 11 ), which also proves that the adhesion of the superhydrophobic film prepared by the physical and chemical double adhesion method is higher than that of the other two types.

[0106] Furthermore, the sand-drop experiment reveals the significant improvement in the stable adhesion and wear resistance of the superhydrophobic polyethylene film prepared by the physical and chemical dual adhesion method. In the sand-drop experiment, the change in the contact angle is measured after every 10 mL of sand grains are dropped, and the specific test results are as Figure 12 shown.

[0107] Figure 12 This is the contact angle change diagram of the superhydrophobic polyethylene films in Example 1, Comparative Example 1, and Comparative Example 2 of the present invention in the sand-drop experiment.

[0108] As Figure 12 shown, for the superhydrophobic polyethylene films prepared only by the physical adhesion method (Comparative Example 1) or the chemical adhesion method (Comparative Example 2), the contact angle drops from 158 ± 2° to about 150° after the first sand drop. As the sand dropping continues, the contact angle drops sharply. However, for the superhydrophobic polyethylene film prepared by the physical and chemical dual adhesion method (Example 1), the contact angle drops to 150° only after 30 mL of sand drops. This result shows that the anti-sand-drop performance of the superhydrophobic polyethylene film prepared by the physical and chemical dual adhesion method is twice that of the superhydrophobic polyethylene film prepared by a single physical adhesion method or chemical adhesion method.

[0109] In summary, the present invention realizes the physical and chemical dual adhesion between inorganic nanoparticles (superhydrophobic inorganic particles or hydrophilic inorganic particles) and polymer films through the coupling reaction in cooperation with the hot pressing method, and prepares a superhydrophobic polymer film with a stable and durable interface. The inorganic particles and the polymer main chain activated by the thermal initiator are coupled by chemical bonds through a coupling agent, and a part of the inorganic nanoparticles are embedded into the polymer film by hot pressing, forming physical adhesion while significantly increasing the interface area between the inorganic particles and the polymer film, generating more chemical coupling reactions, and enhancing the chemical adhesion. Therefore, the contact angle of the superhydrophobic polymer film prepared by the method provided by the present invention can reach 165°, the anti-tape adhesion performance is twice that of single hot pressing, and the slag dropping rate is reduced by 50%. In addition, the superhydrophobic polymer film has good hydrophobicity, durability, and wear resistance, and is suitable for popularization and application in fields such as food packaging and waterproof rain gear; moreover, the preparation method of the superhydrophobic polymer film of the present invention is relatively simple, has low cost, good continuity, and can achieve mass preparation.

[0110] The specific embodiments described above further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a superhydrophobic polymer film by a chemically coupled enhanced hot pressing method, characterized in that The method includes: Mixing inorganic particles, an organic solvent, a coupling agent, and a thermal initiator uniformly to obtain a coating, where the inorganic particles are superhydrophobic inorganic particles or hydrophilic inorganic particles; Loading the coating onto the surface of a polymer film and air-drying it to obtain a polymer film covered with inorganic particles; Performing hot pressing on the polymer film covered with inorganic particles so that a part of the inorganic particles is embedded into the polymer film, and activating the thermal initiator to induce activation of the polymer film. The activated polymer film undergoes a chemical coupling reaction with the inorganic particles through the coupling agent to obtain the chemically coupled enhanced polymer film; Wherein, when the inorganic particles are hydrophilic inorganic particles, the obtained chemically coupled enhanced polymer film or the hydrophilic inorganic particles therein are subjected to superhydrophobic treatment.

2. The method according to claim 1, wherein The inorganic particles are selected from any one of metal oxides and non-metal oxides; The particle size of the inorganic particles is 1 nm - 50 μm, and a part of the hydroxyl groups on the surface of the inorganic particles undergoes a chemical coupling reaction with the coupling agent.

3. The method according to claim 2, wherein The coupling agent is a silane coupling agent, and the thermal initiator is a peroxide thermal initiator; Wherein, the silane coupling agent is selected from at least one of 3-(methacryloyloxy)propyltrimethoxysilane, aminopropyltrimethoxysilane, methyltrimethoxysilane, aminopropyltriethoxysilane, and glycidyletheroxypropyltrimethoxysilane; The peroxide thermal initiator is selected from at least one of benzoyl peroxide, dicumyl peroxide, methyl isobutyl phenyl peroxide, dichloroacetic acid peroxide, and hydrogen peroxide; The organic solvent is selected from any one of C1-C3 alcohols and ethyl acetate.

4. The method according to claim 1, wherein The mixing method of the inorganic particles, the organic solvent, the coupling agent, and the thermal initiator is ultrasonic mixing or mechanical stirring mixing; Wherein, the mass ratio of the inorganic particles to the organic solvent, the coupling agent, and the thermal initiator is 450 - 550:15000 - 25000:95 - 105:0.9 - 1.

1.

5. The method according to claim 1, wherein The polymer film is selected from any one of polyethylene, polypropylene, polyvinyl chloride, polylactic acid, and cellulose.

6. The method according to claim 5, wherein Loading the coating onto the surface of the polymer film includes: Putting the polymer film into the coating and lifting the polymer film; or Spraying the coating onto the surface of the polymer film; or Spin-coating the coating onto the surface of the polymer film.

7. The method according to claim 1, wherein The hot pressing method is: flat hot pressing or roll-to-roll hot pressing; Wherein, the temperature of the hot pressing is 110 - 150 °C, the time is 1 - 10 s, and the pressure is 30 - 60 kPa; The superhydrophobic treatment includes: Performing superhydrophobic treatment on the hydrophilic inorganic particles or the chemically coupled enhanced polymer film with perfluorooctyltrichlorosilane.

8. A superhydrophobic polymer film prepared by a chemically coupled enhanced hot pressing method, characterized in that, Includes: A polymer film as a substrate, and inorganic particles partially embedded into the polymer film and chemically coupled with the polymer film; Wherein, the superhydrophobic polymer film prepared by the chemically coupled enhanced hot pressing method is prepared by the method described in any one of claims 1 - 7.

9. The superhydrophobic polymer film according to claim 8, wherein The contact angle of the superhydrophobic polymer film is 150° - 166°; The depth at which the inorganic particles are embedded in the polymer film is 5% - 95% of the diameter of the inorganic particles.

10. Application of the superhydrophobic polymer film prepared by the chemically coupled hot pressing method according to any one of claims 8 - 9 in a packaging film or a waterproof rain gear.

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