A hydrophobic wear-resistant high-transparency film and a preparation method thereof

Abstract

The application discloses a kind of hydrophobic wear-resistant high-transmittance films and preparation methods thereof, the hydrophobic wear-resistant high-transmittance film includes the functional layer and the support layer of lamination;Support layer includes at least one of polycarbonate, polyethersulfone, thermoplastic polyurethane, cyclic olefin polymer;Functional layer includes polyethylene terephthalate and nano oligomeric silsesquioxane;The content of nano oligomeric silsesquioxane is 1% to 5% of the total mass of functional layer, including at least one of tri-silanol isooctyl-POSS, tri-silanol phenyl-POSS, octaphenyl-POSS and dodecaphenyl-POSS;Hydrophobic wear-resistant high-transmittance film is prepared by multilayer co-extrusion, light transmittance is above 80%, water contact angle is greater than 100°.The hydrophobic wear-resistant high-transmittance film of the application has excellent wear resistance, hydrophobicity, self-cleaning and high transparency, and is particularly suitable for consumer electronics, optical equipment, building materials and automotive industry and other fields.

Description

Technical Field

[0001] This invention relates to the field of polyester film technology, and in particular to a hydrophobic, wear-resistant, and high-transmittance film and its preparation method. Background Technology

[0002] With the rapid development of modern technology, people have placed increasingly higher demands on the functionality of thin films, especially in fields with high requirements for material performance, such as consumer electronics, optical equipment, building materials, and the automotive industry. Hydrophobic materials can effectively reduce the interaction between the surface and water molecules, allowing water droplets to form a high contact angle and roll off quickly, thus preventing the accumulation of water stains and dirt. This property is particularly important in applications that require long-term cleanliness, such as electronic displays, touch panels, and building windows. Traditional hydrophobic coating materials are mostly achieved by coating with fluoropolymers or siloxane compounds, which can effectively reduce surface energy and achieve a self-cleaning effect. However, although fluorinated coatings have excellent hydrophobic properties, their environmental friendliness has been widely questioned, especially since their preparation process may generate harmful perfluorinated compounds (PFOA, etc.). Therefore, in recent years, the development of fluorine-free alternative materials with the same or better hydrophobic properties has become a research hotspot. Polysilsesquioxane (POSS) materials, as low surface energy inorganic-organic hybrid materials, have excellent hydrophobicity and also show advantages in environmental protection and biocompatibility, making them one of the ideal candidates for next-generation hydrophobic materials.

[0003] Optical thin films are crucial components of electronic devices, and they are often susceptible to friction, scratches, and wear during daily use, leading to performance degradation. For optical devices, insufficient wear resistance directly impacts light transmittance, image clarity, and overall aesthetics. Therefore, improving the wear resistance of optical thin films is a key issue in the manufacturing of optical components and electronic devices. POSS molecules possess a cage-like organic-inorganic hybrid structure. The inorganic portion (silicon-oxygen framework) of this structure endows the material with high strength and wear resistance, while the organic portion can be chemically modified to impart different functionalities. Compared to traditional inorganic wear-resistant materials, its organic-inorganic hybrid structure offers better compatibility and adjustability with the substrate film. Furthermore, compared to traditional inorganic wear-resistant materials such as silica, its smaller molecular size has less impact on the film's light transmittance. Moreover, the nanostructure of POSS wear-resistant materials exhibits high wear resistance, lightweight, excellent light transmittance, flexible functionalization, and ease of processing, offering several significant advantages over other wear-resistant materials in thin film applications.

[0004] Polycarbonate (PC) and polyethylene terephthalate (PET) are two common optical film materials widely used in electronic displays, touch screens, optical lenses, and other fields. Although PET is widely used due to its low cost and stable physical properties, PC has much higher toughness than PET, making it suitable for use as an optical film subjected to long-term external forces, and its light transmittance is also higher than that of PET.

[0005] In the prior art, there are techniques for preparing composite films of PC and PET for use on the surfaces of optical devices. For example, invention CN109367176A discloses a scratch-resistant transparent film, a scratch-resistant surface product, and a composite sheet, including a PMMA layer on the upper layer and a PET layer disposed on the lower surface of the PMMA layer. The lower surface of the PET layer is provided with a PMMA layer, a PC layer, or a PC layer and a PMMA layer. However, this invention does not take into account the hydrophobic properties required by optical device materials in its design, thus exhibiting significant shortcomings in applications requiring self-cleaning, waterproofing, and stain resistance.

[0006] Invention CN106883439B discloses a modified high-reflection optical film and its preparation method. This invention introduces an amino-containing cage-like polysilsesquioxane structure (POSS) into a fluorinated emulsion polymer to synthesize a fluorinated emulsion copolymer with optical anti-reflection function. The latex particles in the emulsion are uniformly distributed on the substrate surface. Coating this film onto the polyester substrate surface, the cage-like polysilsesquioxane structure forms numerous nanoscale pores on the substrate surface, resulting in a low effective refractive index and thus achieving optical anti-reflection. However, this invention utilizes the cage-like polysilsesquioxane structure (POSS) material in the form of a coating. The anti-reflection effect depends on the uniform distribution of the fluorinated emulsion polymer, requiring a high-precision coating process. Furthermore, the improvement in the material's mechanical properties and abrasion resistance is limited, and the coating layer is prone to gradual loss over time, leading to performance degradation.

[0007] Therefore, how to improve the hydrophobicity, self-cleaning properties and wear resistance of PET and PC composite optical films while maintaining high light transmittance, and how to achieve long-term performance stability of the materials through a simpler processing technology, based on the structural and performance characteristics of PET and PC composite optical films, has become a key problem that needs to be solved by those skilled in the art. Summary of the Invention

[0008] To address the shortcomings of the existing technology, this invention provides a hydrophobic, wear-resistant, and high-transparency film and its preparation method. The hydrophobic, wear-resistant, and high-transparency film uses PC and PET as base materials and employs nano-oligomeric silsesquioxanes to achieve excellent wear resistance, hydrophobicity, self-cleaning properties, and high transparency. It is particularly suitable for fields with high requirements for comprehensive material performance, such as consumer electronics, optical equipment, building materials, and the automotive industry.

[0009] In a first aspect, the present invention provides a hydrophobic, wear-resistant, and highly transparent thin film, comprising a stacked support layer and a functional layer;

[0010] The support layer includes at least one of polycarbonate, polyethersulfone, thermoplastic polyurethane, and cyclic olefin polymer;

[0011] The functional layer includes polyethylene terephthalate and nano-oligomeric silsesquioxane;

[0012] The content of the nano-oligomeric silsesquioxane is 1%-5% of the total mass of the functional layer, including at least one of trisilyl isooctyl-POSS, trisilyl phenyl-POSS, octaphenyl-POSS, and dodecylphenyl-POSS.

[0013] The hydrophobic, wear-resistant, and highly transparent film is prepared by multi-layer co-extrusion, with a light transmittance of over 80% and a water contact angle of over 100°.

[0014] The support layer of this invention uses polycarbonate (PC), polyethersulfone (PES), thermoplastic polyurethane (TPU), and cyclic olefin polymer (COC), all of which are support materials with excellent mechanical properties and light transmittance. The functional layer uses polyethylene terephthalate (PET) as the substrate and adds 1%-5% nano-oligomeric silsesquioxane (POSS) to form a hydrophobic and abrasion-resistant protective layer on the film surface. This allows water droplets to form a high contact angle on the surface and roll off quickly, achieving a self-cleaning effect, while also significantly enhancing scratch resistance. At the same time, the specific type and content of POSS are controlled to avoid affecting the optical transmittance of the film, thereby achieving synergistic optimization of mechanical properties, optical properties, and surface functionality.

[0015] Preferably, the support layer comprises polycarbonate with a thickness of 10-50 μm;

[0016] The thickness of the functional layer is 10-40 μm;

[0017] The light transmittance of the hydrophobic, wear-resistant, and high-transmittance film is above 85%, preferably above 88%; the water contact angle is above 105°, preferably between 110° and 125°.

[0018] Preferably, under 1000 cycles of CS-10 grinding wheel and 500g load, the mass loss of the hydrophobic, wear-resistant, and highly transparent film is less than 15mg, and more preferably less than 12mg.

[0019] Preferably, the functional layer further includes a compatibilizer, the content of which is 2%-9% of the total mass of the functional layer;

[0020] The compatibilizer includes at least one of maleic anhydride-grafted polypropylene, SEBS-grafted maleic anhydride, ethylene-vinyl acetate-grafted maleic anhydride, and epoxidized polypropylene.

[0021] Compatibilizers are used to improve the compatibility between PET and PC at the bilayer interface, enhance interlayer bonding, and ensure the long-term stability of the film.

[0022] Preferably, the nano-oligomeric silsesquioxane is compounded by at least two of the first POSS, the second POSS, and the third POSS, wherein:

[0023] The first POSS includes trisilyl phenyl-POSS;

[0024] The second POSS includes at least one of octaphenyl-POSS and dodecylphenyl-POSS;

[0025] The third POSS includes trisilyl isooctyl-POSS.

[0026] Nano-oligomeric silsesquioxanes exhibit high wear resistance, lightweight, excellent light transmittance, flexible functionalization, and easy processability. Their cage-like organic-inorganic hybrid structure further enhances their superior and flexible overall performance. The inorganic portion (siloxane framework) imparts high strength and wear resistance, while the organic portion can be chemically modified to provide different functionalities. Compared to traditional inorganic wear-resistant materials, their organic-inorganic hybrid structure offers better compatibility and adjustability with the substrate film. Furthermore, compared to traditional inorganic wear-resistant materials such as silica, their smaller molecular size has minimal impact on the film's light transmittance. Based on these individual characteristics of oligomeric silsesquioxanes, this invention further utilizes them in compound formulations to better demonstrate their positive effects in composite films.

[0027] Preferably, the oligomeric silsesquioxane is compounded by the first POSS, the second POSS and the third POSS in a mass ratio of (3-6):(2-4):(2-4).

[0028] The significant steric hindrance effect of the phenyl groups in the first POSS (trisilyl phenyl-POSS), the second POSS (octaphenyl-POSS), and the dodecyl phenyl-POSS enhances intermolecular interactions, thereby significantly improving the abrasion resistance of the film. Secondly, the phenyl structure possesses good optical transparency, and since the POSS molecule itself is small, introducing POSS into the film does not significantly affect light transmittance, allowing the composite film to achieve better abrasion resistance while maintaining high transparency. In the third POSS, the isooctyl group in the trisilyl isooctyl-POSS provides significant hydrophobicity, forming a low-surface-energy nano-protective layer on the PET surface, significantly improving the film's hydrophobicity and self-cleaning effect. When the total amount of oligomeric silsesquioxanes is controlled at 1%-5% of the total mass of the functional layers, a relatively ideal balance can be achieved between hydrophobicity, abrasion resistance, compatibility, and dispersibility.

[0029] Specifically, the trisilanol phenyl-POSS in the first POSS, with its silanol group (-Si-OH), can form intermolecular forces with the C=O or -OH terminal groups on the PET molecular chain through hydrogen bonds. This helps improve the compatibility of the two and the uniformity of POSS dispersion in the PET matrix, and can also significantly improve the rigidity and strength of PET while maintaining a certain degree of toughness. Furthermore, the synergistic effect of the phenyl and silanol groups helps improve the thermal stability and heat distortion temperature of PET, resulting in a wider operating temperature range.

[0030] For the second POSS, the C=O group of PET is highly polar, while the polarity of octaphenyl-POSS and dodecylphenyl-POSS is extremely low, resulting in slightly lower compatibility with PET. However, octaphenyl-POSS and dodecylphenyl-POSS have outstanding effects on enhancing the thermal stability, mechanical strength and flame retardant properties of the polymer matrix. Therefore, when selecting them, the present invention preferably pre-epoxidizes octaphenyl-POSS and dodecylphenyl-POSS.

[0031] Preferably, the second POSS undergoes an epoxidation treatment, including the following steps:

[0032] S1. Add the second POSS, epichlorohydrin and base catalyst sequentially to anhydrous tetrahydrofuran and stir, then heat under reflux to obtain a mixed solution.

[0033] S2. After cooling the mixed solution, wash it with an inorganic solvent until the washing solution is neutral, then dry it to remove the inorganic solvent and obtain the crude product.

[0034] S3. The crude product is subjected to vacuum evaporation and drying to remove the organic solvent, resulting in the second POSS after epoxidation treatment.

[0035] More preferably, in step S1, the second POSS, epichlorohydrin, and alkaline catalyst are added in stages. The second POSS is added to anhydrous tetrahydrofuran solvent under a nitrogen atmosphere and stirred thoroughly. Then, epichlorohydrin is slowly added dropwise over 5-12 minutes and stirred thoroughly. Finally, the alkaline catalyst is added and the solvent is placed under a nitrogen atmosphere and subjected to constant temperature heating and reflux treatment in an oil bath at 50-70°C for 6-8 hours.

[0036] In step S2, the inorganic solvent includes an inorganic acid solution and deionized water, wherein the inorganic acid solution is preferably a hydrochloric acid solution; preferably, anhydrous sodium sulfate is used to dry the organic phase and the desiccant is removed by filtration.

[0037] For the third POSS, the isooctyl group is a nonpolar alkyl chain with strong hydrophobicity, but its compatibility with the polar molecular chains of PET is low. Excessive use can weaken the dispersion ability of trisilyl isooctyl-POSS in PET. Therefore, this invention adds the third POSS during PET synthesis, pre-dispersing it in the small-molecule polymerizable monomers. During the polymerization of ethylene glycol and terephthalic acid, the trisilyl isooctyl-POSS embeds into the PET molecular chains, forming an in-situ dispersion and uniformly depositing in the PET matrix. This avoids the aggregation phenomenon that occurs with the later addition of the third POSS. Furthermore, the POSS structure introduced by in-situ dispersion has a smaller molecular scale, and after uniform dispersion, it does not significantly affect the optical transparency of PET. Moreover, the dispersion of the third POSS helps reduce the crystallization tendency of PET, thus improving its light transmittance.

[0038] Preferably, the third POSS is added during the preparation of polyethylene terephthalate to obtain modified polyethylene terephthalate, comprising the following steps:

[0039] The trisilyl isooctyl-POSS was mixed with ethylene glycol and a catalyst, then mixed with terephthalic acid, heated, and reacted under vacuum.

[0040] Secondly, the present invention also provides a method for preparing the hydrophobic, wear-resistant, and high-transmittance thin film, comprising the following steps:

[0041] S1. Dry the raw materials in each layer;

[0042] S2. Add nano-oligomeric silsesquioxane and optional compatibilizer to PET and mix to obtain functional layer co-extruded material;

[0043] S3. Add the functional layer co-extrusion material and the support layer material to an extruder to melt and co-extrude to obtain a thick sheet;

[0044] S4. The thick sheet is stretched to obtain the hydrophobic, wear-resistant, and high-transmittance film.

[0045] Preferably, in step S2, the extrusion screw speed is 60-90 r / min, more preferably 70-80 r / min, and the temperature is 260-300℃, more preferably 270-290℃; and / or

[0046] In step S3, during co-extrusion, the support layer material is added to the main extruder at a temperature of 260-290℃; the functional layer co-extrusion material is added to the auxiliary extruder at a temperature of 255-285℃, preferably 270-285℃.

[0047] Preferably, in the co-extrusion step S3, an electrostatic voltage of 6-7 kV is applied to the extruder die, the temperature of the cold roll is below 20°C, and the rotation speed of the cold roll is 10-20 m / min, resulting in a sheet thickness of 500-1200 μm. Applying electrostatic charge to the die ensures that the extrudate accurately adheres to the cold roll for rapid cooling, thereby increasing the degree of supercooling and effectively reducing the crystallinity of the sheet.

[0048] Preferably, in step S4, the stretching process for the thick sheet includes:

[0049] S4.1 Preheating of thick sheets: preheating temperature 80-120℃, preheating time 30-90 seconds;

[0050] S4.2 Simultaneous biaxial stretching of preheated thick sheets at a stretching temperature of 110-140℃, with a stretching ratio of (3-4):1 for the X-axis to the Y-axis, yields a stretched film.

[0051] S4.3 is used for shaping the stretched film at a temperature of 100-120℃.

[0052] The present invention has at least the following beneficial effects:

[0053] (1) This invention achieves excellent mechanical properties, optical properties, and surface functionality of the film through a multi-layer structure design of support and functional layers, combined with the synergistic effect of high-performance materials PC, PET, and nano-oligomeric silsesquioxane (POSS). While ensuring high light transmittance (above 85%), the film also possesses excellent abrasion resistance, hydrophobicity, and structural stability, making it suitable for optical, electronic, and high-requirement industrial protection applications.

[0054] (2) This invention, through the compounding of trisilyl phenyl-POSS, octaphenyl-POSS and / or dodecyl-POSS and trisilyl isooctyl-POSS, and especially by selecting specific compounding and introduction methods according to the characteristics of each POSS, significantly enhances the interfacial bonding force between polar and non-polar materials between film layers, improves dispersibility and uniformity, and ensures uniform and stable hydrophobic, wear-resistant, high light transmittance and comprehensive mechanical properties of the film product, including:

[0055] The second POSS was subjected to epoxidation treatment, which introduced active epoxy groups on its surface. This significantly enhanced the interfacial compatibility and chemical stability between the second POSS and the matrix material, and further improved the wear resistance and thermal stability of the film.

[0056] The third POSS is introduced into PET in situ to ensure uniform dispersion of POSS in the matrix, avoiding performance degradation caused by particle aggregation. This not only improves the mechanical properties and surface hydrophobicity of the film, but also maintains high light transmittance and excellent optical properties, combining process simplification and long-term performance stability. Attached Figure Description

[0057] Figure 1 This is a schematic diagram of the structure of the hydrophobic, wear-resistant, and high-transmittance film of the present invention.

[0058] Figure 2 This is a physical image of the hydrophobic, wear-resistant, and high-transmittance film of the present invention.

[0059] Figure label: 1-Support layer, 2-Functional layer. Detailed Implementation

[0060] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the specification and specific implementation methods. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0062] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0063] The following will be combined with the appendix Figure 1-2 The present invention describes the hydrophobic, wear-resistant, and high-transmittance thin film and its preparation method.

[0064] A hydrophobic, wear-resistant, and high-transmittance thin film, see attached. Figure 1 ,include:

[0065] (1) Support layer 1, with a thickness of 10-50 μm, including at least one of polycarbonate, polyethersulfone, thermoplastic polyurethane, and cyclic olefin polymer.

[0066] (2) Functional layer 2, with a thickness of 10-40 μm, includes polyethylene terephthalate and 1%-5% of nano-oligomeric silsesquioxane by total mass, and optional compatibilizer;

[0067] The compatibilizer, with a content of 2%-9% of the total mass of the functional layer 2, includes at least one of maleic anhydride-grafted polypropylene, SEBS-grafted maleic anhydride, ethylene-vinyl acetate-grafted maleic anhydride, and epoxidized polypropylene.

[0068] The nano-oligomeric silsesquioxanes include at least one of the following: trisilyl isooctyl-POSS, trisilyl phenyl-POSS, octaphenyl-POSS, and dodecylphenyl-POSS.

[0069] Based on the property differences of different types of nano-oligomeric silsesquioxanes, the nano-oligomeric silsesquioxanes of the present invention are preferably compounded, that is, compounded by at least two of the first POSS, the second POSS, and the third POSS, more preferably compounded by the first POSS, the second POSS, and the third POSS in a mass ratio of (3-6):(2-4):(2-4), wherein:

[0070] (1) The first POSS includes trisilyl phenyl-POSS, which has good compatibility with PET matrix and can be directly added to PET for blending.

[0071] (2) The second POSS includes at least one of octaphenyl-POSS and dodecylphenyl-POSS. The second POSS is pre-epoxidized, which can significantly improve its compatibility with the PET matrix. After pretreatment, it is added to PET for blending.

[0072] (3) The third POSS includes trisilyl isooctyl-POSS. Trisilyl isooctyl-POSS has excellent hydrophobicity, but its compatibility with the PET matrix needs to be further improved. Therefore, it is added to PET by in-situ dispersion. Specifically, it includes mixing trisilyl isooctyl-POSS with ethylene glycol and catalyst, then mixing with terephthalic acid, heating, and vacuuming to react and prepare modified polyethylene terephthalate.

[0073] The second POSS, specifically the octaphenyl-POSS and / or dodecyl-POSS, undergoes epoxidation treatment, including the following steps:

[0074] S1. Add 0.5-0.8 mmol of the second POSS and an appropriate amount of anhydrous tetrahydrofuran solvent (about 15-25 ml) to a three-necked flask, and stir under nitrogen protection to dissolve it completely.

[0075] S2. Slowly add epichlorohydrin dropwise to the flask. The molar ratio of epichlorohydrin to the second POSS is approximately (3-6):1. The addition time is controlled at 5-10 min. After the addition is complete, continue stirring for 20-35 min.

[0076] S3. Add an alkaline catalyst (KOH and / or NaOH), with the molar ratio of the alkaline catalyst to the second POSS being (1-3):1;

[0077] S4. Heat the reaction mixture under reflux in an oil bath at 60±2℃ for 6-8 hours, maintain a constant temperature, and continue stirring under nitrogen protection.

[0078] S5. After the reaction is complete, cool the reaction solution to room temperature;

[0079] S6. Use an inorganic acid solution, preferably hydrochloric acid solution, to wash the organic phase to neutralize the residual alkaline catalyst; then wash with deionized water 3-5 times until the washing solution is neutral; dry the organic phase with anhydrous sodium sulfate, and then filter to remove the desiccant.

[0080] S7. Remove the anhydrous tetrahydrofuran solvent from the filtrate by rotary evaporation under reduced pressure.

[0081] S8. The residue is dried in a vacuum drying oven to obtain the second POSS with epoxy functionalization.

[0082] The following preparation method is provided for the aforementioned hydrophobic, wear-resistant, and high-transmittance thin film, specifically including the following steps:

[0083] S1. Dry the optical grade PET slices at 100-150℃ for 6-24 hours, and dry the nano-oligomeric silsesquioxane powder in a freeze dryer for 6-24 hours to remove moisture.

[0084] S2. Nano-oligomeric silsesquioxane and optional compatibilizer are added to PET and the functional layer co-extrusion material is prepared by melt blending using a micro twin-screw extruder, wherein the screw speed is set to 60-90 r / min and the temperature is set to 260-300℃.

[0085] S3. Add the functional layer co-extrusion material to the hopper of the auxiliary twin-screw extruder. The extrusion temperature of the auxiliary extruder is 255-285℃, preferably 265-275℃. Add the PC chips to the hopper of the main twin-screw extruder. The extrusion temperature of the main extruder is 260-290℃, preferably 270-285℃. Melt co-extrusion is performed to obtain thick sheets.

[0086] Among them, the electrostatic voltage applied to the extruder die is 6-7kV, the temperature of the cold roll is below 20℃, the speed of the cold roll is 10-20m / min, and the thickness of the sheet is 500-1200μm with a crystallinity of less than 3%.

[0087] S4. Stretching the thick sheet, including:

[0088] S4.1 Preheating of thick sheets: preheating temperature 80-120℃, preheating time 30-90 seconds;

[0089] S4.2 Simultaneous biaxial stretching of preheated thick sheets is performed at a stretching temperature of 110-140℃, with a stretching ratio of (3-4):1 between the X-axis and Y-axis, to obtain a stretched film; the X-axis and Y-axis are mutually perpendicular axes, also referred to as the transverse axis (TD) and the longitudinal axis (MD);

[0090] S4.3 is used for shaping the stretched film at a temperature of 100-120℃.

[0091] Example 1

[0092] A hydrophobic, wear-resistant, and high-transmittance thin film includes:

[0093] (1) Support layer, 10μm thick, made of PC;

[0094] (2) Functional layer, with a thickness of 10μm, is selected from PET and 3% of the total mass of the functional layer isooctyl trisilyl-POSS, and 5% of the total mass of the functional layer is maleic anhydride grafted polypropylene compatibilizer.

[0095] The preparation method of the hydrophobic, wear-resistant, and high-transmittance thin film specifically includes the following steps:

[0096] S1. Dry the optical grade PET slices at 120℃ for 12 hours, and dry the trisilyl phenyl-POSS powder in a freeze dryer for 12 hours to remove moisture;

[0097] S2. Trisilyl phenyl-POSS and compatibilizer are added to PET and the functional layer co-extrusion material is prepared by melt blending using a micro twin-screw extruder, wherein the screw speed is set to 75 r / min and the temperature is set to 280℃.

[0098] S3. Add the functional layer co-extrusion material to the auxiliary twin-screw extruder hopper, with the auxiliary extruder extrusion temperature at 270℃; add the PC chips to the main twin-screw extruder hopper, with the main extruder extrusion temperature at 280℃.

[0099] Thick sheets are obtained by melt co-extrusion;

[0100] An electrostatic voltage of 6.5kV was applied to the extruder die, the temperature of the cold roll was 15±1℃, and the speed of the cold roll was 15m / min to obtain a co-extruded sheet.

[0101] S4. Simultaneous biaxial stretching of thick sheets includes:

[0102] S4.1 Preheat the thick sheet at a temperature of 100℃ for 60 seconds.

[0103] S4.2 Simultaneous biaxial stretching of the preheated thick sheet was performed at a stretching temperature of 125℃, with a stretching ratio of 3.5:1 between the X and Y axes, to obtain a stretched film.

[0104] S4.3 is used for shaping the stretched film at a temperature of 110°C.

[0105] Example 2-3

[0106] The difference between Examples 2-3 and Example 1 is that the thickness of the co-extruded sheet is different, and the thickness of the support layer and the functional layer are different after synchronous biaxial stretching.

[0107] Examples 4-5

[0108] The difference between Examples 4-5 and Example 1 is that the content of nano-oligomeric silsesquioxane in the functional layer is different.

[0109] Example 6

[0110] The difference between Example 6 and Example 1 is that the nano-oligomeric silsesquioxane uses only octaphenyl-POSS that has undergone epoxidation treatment, which includes the following steps:

[0111] S1. Add 0.6 mmol of octaphenyl-POSS and 20 ml of anhydrous tetrahydrofuran solvent to a three-necked flask, and stir under nitrogen protection until completely dissolved.

[0112] S2. Slowly add epichlorohydrin to the flask. The molar ratio of epichlorohydrin to octaphenyl-POSS is about 5:1. The addition time is controlled at 10 min. After the addition is completed, continue stirring for 30 min.

[0113] S3. Add KOH catalyst, with a KOH to octaphenyl-POSS molar ratio of 2:1;

[0114] S4. Heat the reaction mixture under reflux in an oil bath at 60±2℃ for 6 hours, maintain a constant temperature, and continue stirring under nitrogen protection.

[0115] S5. After the reaction is complete, cool the reaction solution to room temperature;

[0116] S6. Wash the organic phase with hydrochloric acid solution to neutralize the residual KOH; then wash with deionized water 3-5 times until the washing solution is neutral; dry the organic phase with anhydrous sodium sulfate, and then filter to remove the desiccant.

[0117] S7. Remove the anhydrous tetrahydrofuran solvent from the filtrate by rotary evaporation under reduced pressure.

[0118] S8. The residue was dried in a vacuum drying oven to obtain epoxy-functionalized octaphenyl-POSS.

[0119] Example 7

[0120] The difference between Example 7 and Example 1 is that the nano-oligomeric silsesquioxane uses only trisilyl isooctyl-POSS, and the trisilyl isooctyl-POSS is dispersed in situ in the PET matrix, including:

[0121] Trisilyl isooctyl-POSS was mixed with ethylene glycol and a catalyst, then mixed with terephthalic acid, heated, and reacted under vacuum to produce modified polyethylene terephthalate.

[0122] Examples 8-12

[0123] The difference between Examples 8-12 and Example 1 is that the nano-oligomeric silsesquioxanes are compounded, wherein the first POSS is trisilyl phenyl-POSS; the second POSS is octaphenyl-POSS after epoxidation treatment; and the third POSS is trisilyl isooctyl-POSS, which are dispersed in situ in the PET matrix.

[0124] Examples 13-14

[0125] The difference between Examples 13-14 and Example 10 is that the stretching ratio is different.

[0126] Comparative Examples 1-2

[0127] The difference between Comparative Examples 1-2 and Example 1 is that the content of nano-oligomeric silsesquioxane in the functional layer is different.

[0128] The main parameters of Examples 1-14 and Comparative Examples 1-2 are shown in Table 1:

[0129] Table 1

[0130]

[0131] Performance testing:

[0132] (1) Light transmittance: Tested according to ISO13468 standard using German BYK HAZE-gard i.

[0133] (2) Hydrophobicity (water contact angle): The contact angle was tested using a G-1 type εrma angle meter manufactured by Kyowa Corporation, Japan. Deionized water was used. Water droplets were placed on the film surface for 1 minute before testing. Three points with a spacing of 5 mm were taken for each sample for measurement. A total of 6 readings were taken and the arithmetic mean was taken.

[0134] (3) Abrasion resistance: The mass loss of the composite film was measured using a CS-10 grinding wheel and a 500g load for 1000 cycles.

[0135] (4) Mechanical properties: tensile strength and elongation at break are tested according to ASTM D882 standard.

[0136] The above tests were performed on Examples 1-14 and Comparative Examples 1-2, and the test results are shown in Table 2:

[0137] Table 2

[0138] transmittance / % Water contact angle mass loss / mg Tensile strength / MPa Example 1 90.3 115° 9.6 170 Example 2 89.8 114° 9.4 195 Example 3 90.1 117° 9.4 181 Example 4 87.7 118° 9.2 179 Example 5 90.5 112° 10.8 185 Example 6 89.1 118° 6.5 186 Example 7 88.5 120° 8.5 189 Example 8 90.1 116° 7.3 190 Example 9 89.3 119° 8.8 181 Example 10 90.3 118° 8.0 185 Example 11 90.5 117° 8.4 187 Example 12 88.1 119° 7.8 182 Example 13 90.0 118° 8.0 184 Example 14 89.8 118° 8.2 182 Comparative Example 1 90.6 100° 12.2 171 Comparative Example 2 83.2 120° 9.0 173

[0139] According to the test results in Table 2, Examples 1-14 exhibit excellent overall performance, with light transmittance all above 80%, preferably above 85%. Most examples, especially those using compounded POSS, achieve light transmittance above 88%. Regarding hydrophobic properties, the water contact angle is greater than 100°, preferably greater than 110°, indicating excellent hydrophobic self-cleaning properties. In terms of abrasion resistance, the mass loss is below 12 mg, with most examples below 10 mg. The samples containing a second POSS show even better overall abrasion resistance, with a mass loss below 9 mg.

[0140] In Comparative Example 1, the content of nano-oligomeric silsesquioxane was relatively low. Although the optical properties were good, the hydrophobicity, abrasion resistance and mechanical properties were slightly insufficient. In Comparative Example 2, the content of nano-oligomeric silsesquioxane was too high, which easily led to a decrease in dispersion uniformity and negatively affected the light transmittance and mechanical properties.

[0141] In summary, this invention, by appropriately adding nano-oligomeric silsesquioxanes and compatibilizers, and especially by selecting specific compounding ratios and introduction methods according to the characteristics of each POSS, significantly enhances the interfacial bonding force between polar and non-polar materials in the film layers, improves dispersibility and uniformity, and ensures that the film product has uniform and stable hydrophobic, wear-resistant, high light transmittance and comprehensive mechanical properties.

[0142] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the invention is intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope.

Claims

1. A hydrophobic, abrasion resistant, high transmission film, characterized in that, The support layer and the functional layer are stacked; The support layer comprises at least one of polycarbonate, polyethersulfone, thermoplastic polyurethane, and cyclic olefin polymer; The functional layer comprises polyethylene terephthalate, nano-oligomeric silsesquioxane, and a compatibilizer; The nano-oligomeric silsesquioxane comprises at least one of trisilanol isooctyl-POSS and trisilanol phenyl-POSS, and the content of the nano-oligomeric silsesquioxane is 1%-5% of the total mass of the functional layer; The hydrophobic wear-resistant high-transmittance film is prepared by multi-layer co-extrusion, has a transmittance of more than 80% and a water contact angle of more than 100°; The trisilanol isooctyl-POSS is added in the preparation of polyethylene terephthalate to obtain modified polyethylene terephthalate, comprising the following steps: mixing the trisilanol isooctyl-POSS with ethylene glycol and a catalyst, then mixing with terephthalic acid, heating, and vacuumizing for reaction; The compatibilizer comprises at least one of maleic anhydride grafted polypropylene, SEBS grafted maleic anhydride, ethylene-vinyl acetate grafted maleic anhydride, and epoxidized polypropylene.

2. The hydrophobic, abrasion-resistant, high-transmission film of claim 1, wherein, The support layer comprises polycarbonate, and the thickness is 10-50μm; The thickness of the functional layer is 10-40μm.

3. The hydrophobic, abrasion-resistant, high-transmission film of claim 2, wherein, The hydrophobic wear-resistant high-transmittance film has a transmittance of more than 85%, a water contact angle of more than 105°, and a tensile strength of more than 170MPa.

4. The hydrophobic, abrasion-resistant, high-transmission film according to any one of claims 1 to 3, wherein The content of the compatibilizer is 2%-9% of the total mass of the functional layer.

5. A method of making a hydrophobic, abrasion resistant, high transmission film as claimed in any one of claims 1 to 4, characterised in that, Comprising the following steps: S1, drying the raw materials of each layer; S2, adding the nano-oligomeric silsesquioxane and the compatibilizer to PET to obtain a functional layer co-extrusion material by mixing; S3, adding the functional layer co-extrusion material and the support layer raw material to the extruder respectively for melting and co-extrusion to obtain a thick sheet; S4, stretching the thick sheet to obtain the hydrophobic wear-resistant high-transmittance film.

6. The production method according to claim 5, wherein In step S2, the screw rotation speed of the extruder is 60-90r / min, and the temperature is 260-300℃.

7. The production method according to claim 5, wherein In the co-extrusion of step S3, the support layer raw material is added to the main extruder, and the temperature is 260-290℃; the functional layer co-extrusion material is added to the auxiliary extruder, and the temperature is 255-285℃.

8. The production method according to claim 5, wherein In the co-extrusion of step S3, the die of the extruder is loaded with an electrostatic voltage of 6-7kV, the cold roller temperature is below 20℃, and the cold roller rotation speed is 10-20m / min, so that the thickness of the thick sheet is 500-1200μm.

9. The production method according to any one of claims 5 to 8, wherein In step S4, the stretching treatment of the thick sheet comprises: S4.1, preheating the thick sheet at a preheating temperature of 80-120℃ for 30-90s; S4.2, synchronously biaxially stretching the preheated thick sheet at a stretching temperature of 110-140℃ to obtain a stretched film with an X-axis to Y-axis stretching ratio of (3-4):1; S4.3, setting the shape of the stretched film at a setting temperature of 100-120℃.

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