Rain-proof and fog-proof film for vehicle

Abstract

The invention belongs to the technical field of automobile safety protection materials, and particularly relates to an automotive rainproof and antifogging film which comprises a transparent flexible substrate, a hydrophobic rainproof layer and a hydrophilic antifogging layer, and the hydrophobic rainproof layer and the hydrophilic antifogging layer are arranged on the surface of the transparent flexible substrate in a partitioned mode. The hydrophobic rainproof layer is formed by compounding fluorine-containing siloxane / silicon dioxide nanoparticles, the water contact angle of the hydrophobic rainproof layer is larger than or equal to 150 degrees, the hydrophilic antifogging layer is formed by compounding polyvinylpyrrolidone / titanium dioxide-silica sol, the water contact angle of the hydrophilic antifogging layer is smaller than or equal to 30 degrees, and the hydrophobic rainproof layer and the hydrophilic antifogging layer are arranged in an array mode of hexagonal hydrophobic units (the diameter ranges from 0.5 mm to 1.5 mm) and latticed hydrophilic areas (the width ranges from 50 micrometers to 200 micrometers) to form a composite functional area. A component gradient transition layer (with the width of 10-30 microns) is arranged at the junction; the edge of the film is integrated with an ultraviolet excitation fluorescence positioning layer, and the back is covered with a pressure-sensitive adhesive layer. According to the film, through the synergistic effect of the micro-nano structure, the rainwater retention time is smaller than or equal to 0.5 second (under the working condition of 80 km / h), the anti-fog response is smaller than or equal to 3 seconds (the humidity suddenly changes from 90% to 20%), the visible light transmittance is larger than or equal to 92%, the function attenuation rate is smaller than 5% after ultraviolet aging is conducted for 500 hours, and the problem of visual impairment in the rain and fog coexistence environment is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile safety protection materials, and more particularly to a rainproof and fogproof film for automobiles. Background Art

[0002] With the development of intelligent vehicles, the clarity of light-transmitting parts such as windshields, side windows, and rearview mirrors directly affects driving safety. In rainy and foggy weather, rainwater retention creates visual blind spots, and water vapor condenses, causing the glass to fog. Traditional solutions such as wipers and air conditioning defoggers have problems such as response delays, high energy consumption, and interference with vision. Functional protective films, as passive solutions, have become a research hotspot due to their advantages such as low cost and the absence of external energy sources. However, existing technologies still have significant drawbacks:

[0003] 1. Conflict between functional singularity and environmental adaptability

[0004] Current rainproof films rely on super-hydrophobic coatings, which, while allowing rain to roll off, can easily cause condensation in high humidity environments. Anti-fog films, on the other hand, prevent fogging by adsorbing water molecules through a hydrophilic layer, but this causes rain to spread out into a film that obstructs vision. These two functions are mutually exclusive, making them incapable of handling the complex real-world conditions of alternating rain and fog, or their coexistence.

[0005] 2. Durability defects and optical performance degradation

[0006] Mainstream hydrophobic coatings mostly use silica nanoparticles. After being irradiated by ultraviolet rays, fluorine elements are precipitated, and the contact angle decays from >150° to <110°; the hydrophilic layer absorbs moisture and expands (such as the polyvinyl alcohol system), causing the film layer to wrinkle, and the haze increases from the initial ≤2% to >10%, causing glare when driving at night, and the mechanical wear resistance is insufficient.

[0007] 3. Insufficient installation accuracy causes functional failure

[0008] Functional coatings need to precisely cover the core visual area (such as the area where the curvature of the rearview mirror changes), but some existing products lack positioning marks. When the deviation of manual film application is ≥3mm, a capillary siphon effect is generated in the overlapping area of ​​the hydrophobic / hydrophilic boundary, causing rainwater to flow back into the hydrophilic area or water vapor to invade the hydrophobic area, and the functional efficiency is reduced by more than 40%.

[0009] Therefore, in view of the above problems, a rainproof and fogproof film for vehicles is proposed. Summary of the Invention

[0010] In order to overcome the above-mentioned defects of the prior art, an embodiment of the present invention provides a rainproof and fogproof film for a vehicle to solve the problems raised in the above-mentioned background technology.

[0011] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: a rainproof and anti-fog film for automobiles, comprising a transparent flexible substrate, the surface of the substrate being partitioned into a hydrophobic rainproof layer and a hydrophilic anti-fog layer; the hydrophobic rainproof layer is composed of a nano-scale hydrophobic material and has a water contact angle ≥150°, and the hydrophilic anti-fog layer is composed of a hygroscopic polymer material and has a water contact angle ≤30°; the two are formed into a composite functional area arranged in a preset array through micro-nano processing, wherein the hydrophobic rainproof layer is a hexagonal unit with a diameter of 0.5mm-1.5mm, and the hydrophilic anti-fog layer constitutes a connected grid with a width of 50μm-200μm between units, and the center distance between adjacent hydrophobic units is 1.8-3.2 times the diameter of the unit circumscribed circle.

[0012] Preferably, the hydrophobic rainproof layer has a thickness of 0.5-5 μm, and is composed of a compound of fluorinated silicone and silica nanoparticles in a mass ratio of 3:1-5:1, and the particle size of the nanoparticles is 20-100 nm; the hydrophilic anti-fog layer has a thickness of 0.2-2 μm, and is composed of a compound of polyvinyl pyrrolidone and titanium dioxide-silica sol in a ratio of 1:0.3-1:0.6, and its surface has a micron-sized pit structure to enhance the water vapor adsorption capacity.

[0013] Preferably, a transition structure with a gradual composition gradient is provided at the junction of the hydrophobic rainproof layer and the hydrophilic anti-fog layer. The structure is formed by plasma-assisted vapor deposition. The width of the transition zone is 10-30 μm, and the fluorine element content linearly decreases from 90 at% to 5 at%, and the oxygen element content increases from 5 at% to 45 at%, so that the interlayer peeling strength reaches 8-12 N / cm.

[0014] Preferably, a fluorescent positioning layer is integrated at the edge of the composite functional area. The layer is composed of europium-doped yttrium vanadate phosphor and polymethyl methacrylate in a mass ratio of 1:9-2:8, with a thickness of 5-15 μm. It emits green fluorescence with a peak of 542 nm under 365 nm ultraviolet light excitation and a brightness of ≥300 cd / m 2 .

[0015] Preferably, the transparent flexible substrate is a biaxially stretched polyethylene terephthalate film with a thickness of 50-150 μm, and the surface is treated with oxygen plasma to a roughness Ra of 0.05-0.2 μm; the overall visible light transmittance of the film is ≥92%, the haze is ≤1.5%, and the ultraviolet blocking rate is ≥99%.

[0016] Preferably, a pressure-sensitive adhesive layer and a release film are sequentially provided on the back of the film. The pressure-sensitive adhesive layer is a cross-linked acrylate copolymer with a thickness of 25-100 μm and contains glass microbead spacers with a particle size of 1-5 μm. Its 180° peel strength is 8-15 N / cm, the stickiness is greater than 72h / 1kg, and the moisture and heat resistance meets the requirement of no falling off for 500 hours under an environment of 85°C / 85% RH.

[0017] Preferably, the composite functional area accounts for 90%-95% of the total surface area of ​​the membrane, and the non-functional area is a surrounding installation positioning belt with a width of 2-3 mm and a surface having a laser-etched millimeter-level positioning cross mark.

[0018] Preferably, after 500 hours of UV aging test according to ISO4892-3 standard, the water contact angle of the hydrophobic area decays ≤8° and the rolling angle ≤10°; the anti-fog performance of the hydrophilic area is maintained for ≥1200 hours without fogging in an environment where the temperature suddenly changes from 50°C to -20°C.

[0019] Preferably, the hexagonal hydrophobic unit area accounts for 60%-70%, and the surface of the grid-like hydrophilic area is provided with a micropore array with a depth of 0.1-0.5 μm and a diameter of 2-5 μm, and a porosity of 15%-25%, so that the water vapor diffusion rate reaches 0.8-1.2 g / (m 2 ·h).

[0020] Preferably, in an environmental test at a vehicle speed ≥ 80 km / h, the rainwater retention time on the membrane surface is ≤ 0.5 seconds, the anti-fog response time is ≤ 3 seconds (relative humidity 90% to 20% sudden change working condition), and the optical distortion value Δn is ≤ 0.001.

[0021] Technical effects and advantages of the present invention:

[0022] Compared with the existing technology, the present invention constructs a micro-nano array structure of a hydrophobic rainproof layer and a hydrophilic anti-fog layer through partitioning the surface of a transparent substrate. It uses a dual-functional synergistic mechanism of hexagonal hydrophobic units to quickly guide away rainwater and grid-shaped hydrophilic areas to efficiently diffuse water vapor, thereby simultaneously solving the problems of rainwater retention and fogging; the gradient transition layer formed by plasma deposition eliminates interfacial stress concentration and ensures the stability of interlayer bonding; the edge integrates an ultraviolet-excited fluorescent layer and laser-etched positioning markings to achieve precise alignment and installation of curved glass; the overall structure optimizes the micro-area arrangement of hydrophobic and hydrophilic components and selects optical-grade substrate materials, while maintaining high light transmittance, breaking through the environmental adaptability limitations of traditional functional films, and significantly improving the clarity and safety of driving vision under complex weather conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a system framework diagram of the present invention.

[0024] Figure 2 It is the workflow diagram of the present invention. DETAILED DESCRIPTION

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] Example 1:

[0027] As attached Figure 1-2 As shown, (1) a rainproof and anti-fog film for automobiles, comprising a transparent flexible substrate, the surface of which is divided into a hydrophobic rainproof layer and a hydrophilic anti-fog layer; the hydrophobic rainproof layer is composed of a nano-scale hydrophobic material and has a water contact angle of ≥150°, and the hydrophilic anti-fog layer is composed of a hygroscopic polymer material and has a water contact angle of ≤30°; the two are formed into a composite functional area arranged in a preset array through micro-nano processing, wherein the hydrophobic rainproof layer is in the form of hexagonal units with a diameter of 0.5mm-1.5mm, and the hydrophilic anti-fog layer is composed of a connected grid with a width of 50μm-200μm between units, and the center distance between adjacent hydrophobic units is 1.8-3.2 times the diameter of the unit circumscribed circle, wherein the transparent flexible substrate is a biaxially stretched PET film (model ST504, Toray Industries, Ltd.) with a thickness of 100μm, which is treated with oxygen plasma (power 300W, time 30s) to make the surface roughness Ra = 0.12μm. A nanoimprinting process was used to create composite functional zones on the substrate surface. The hydrophobic rainproof layer consists of 1.0mm-diameter hexagonal units, composed of a 4:1 mass ratio of fluorosilicone (Shin-Etsu Chemical KF-96) and 50nm hydrophobic silica nanoparticles (Evonik AEROSIL R8200), achieving a water contact angle of 158°. The hydrophilic antifog layer, a 150μm-wide interconnected grid, is composed of a 1:0.4 ratio of polyvinylpyrrolidone (PVP K30) and titanium dioxide-silica sol (DuPont TYZOR), achieving a water contact angle of 28°. The center-to-center spacing of adjacent hydrophobic units is 2.5mm (2.5 times their diameter). The units are positioned by laser etching and then formed by slit coating.

[0028] (2) The hydrophobic rainproof layer has a thickness of 0.5-5 μm and is composed of a composite of fluorinated silicone and silica nanoparticles in a mass ratio of 3:1-5:1, with a nanoparticle size of 20-100 nm; the hydrophilic anti-fog layer has a thickness of 0.2-2 μm and is composed of a composite of polyvinyl pyrrolidone and titanium dioxide-silica sol in a ratio of 1:0.3-1:0.6, with a micron-scale pit structure on its surface to enhance water vapor adsorption capacity. The hydrophobic rainproof layer has a coating thickness of 2. 5μm, the coating liquid contains 15wt% fluorosilicone, 5wt% silica nanoparticles and 80wt% ethanol solvent, and is cured at 80℃ for 10min; the hydrophilic anti-fog layer coating thickness is 1.2μm, the coating liquid contains 20wt% PVP, 8wt% titanium dioxide-silica sol and 72wt% deionized water, and after drying at 60℃, a pit array with a depth of 0.3μm and a diameter of 3μm is formed by microneedle roller imprinting, with a porosity of 20% and a specific surface area increased by 3.2 times.

[0029] (3) A transition structure with a gradient composition is provided at the interface between the hydrophobic rainproof layer and the hydrophilic anti-fog layer. This structure is formed by plasma-assisted vapor deposition. The width of the transition zone is 10-30 μm, in which the fluorine content decreases linearly from 90 at% to 5 at%, and the oxygen content increases from 5 at% to 45 at%, so that the interlayer peel strength reaches 8-12 N / cm. The transition layer adopts a plasma-assisted vapor deposition (PECVD) process: a mixed gas of hexamethyldisiloxane (HMDSO) and oxygen (flow ratio 10:1) is introduced into the hydrophobic / hydrophilic layer interface. Under a radio frequency power of 200 W, the HMDSO flow rate is gradually adjusted from 100 sccm to 10 sccm (time 5 min), forming a gradient zone with a width of 20 μm. XPS detection shows that the fluorine atomic concentration decreases linearly from 88 at% to 6 at%, and the oxygen atomic concentration increases from 7 at% to 42 at%, and the interlayer peel strength reaches 10.5 N / cm.

[0030] (4) A fluorescent positioning layer is integrated at the edge of the composite functional area. The layer is composed of europium-doped yttrium vanadate phosphor and polymethyl methacrylate in a mass ratio of 1:9-2:8, with a thickness of 5-15 μm. It emits green fluorescence with a peak of 542 nm under 365 nm ultraviolet light excitation, with a brightness of ≥300 cd / m 2 The fluorescent positioning layer is made of europium-doped yttrium vanadate (YVO4:Eu 3+ ) phosphor and PMMA (Mitsubishi Rayon VH001) were mixed in a mass ratio of 1.5:8.5, dissolved in ethyl acetate to form a 25wt% solid content slurry, and screen-printed on the outer edge of the composite functional area with a thickness of 10μm. The emission peak under 365nm ultraviolet excitation was 542nm and the brightness was 350cd / m 2 (BM-7 luminance meter test), positioning accuracy ±0.3mm.

[0031] (5) The transparent flexible substrate is a biaxially stretched polyethylene terephthalate film with a thickness of 50-150 μm, and the surface is treated with oxygen plasma to a roughness of Ra = 0.05-0.2 μm; the overall visible light transmittance of the film is ≥92%, the haze is ≤1.5%, and the ultraviolet blocking rate is ≥99%, wherein the PET substrate is formed by biaxial stretching (longitudinal / transverse stretching ratio of 3.5:1), and the surface oxygen plasma treatment power density is 0.8 W / cm 2 The film has an overall light transmittance of 92.5% (GB / T 2410-2008), a haze of 1.2%, and a UV blocking rate of 99.8% (measured by a UV-3600 spectrophotometer in the 290-400nm band).

[0032] (6) A pressure-sensitive adhesive layer and a release film are sequentially provided on the back of the film. The pressure-sensitive adhesive layer is a cross-linked acrylic copolymer with a thickness of 25-100 μm and contains glass microbead spacers with a particle size of 1-5 μm. Its 180° peel strength is 8-15 N / cm, its adhesiveness is greater than 72 h / 1 kg, and its moisture and heat resistance meets the requirement of no peeling after 500 hours at 85°C / 85% RH. The pressure-sensitive adhesive layer is an isooctyl acrylate-acrylic acid copolymer (solid content 40%), with 0.5 wt% of 3 μm diameter glass microbeads (3M iM30k) added, with a coating thickness of 50 μm and cross-linked at 120°C for 3 minutes. The 180° peel strength is 12.8 N / cm (GB / T 2792), the adhesiveness is greater than 168 h / 1 kg (GB / T4851), and there is no warping or peeling after 600 hours of moisture and heat testing at 85°C / 85% RH.

[0033] (7) The composite functional area accounts for 90%-95% of the total surface area of ​​the membrane, and the non-functional area is a surrounding installation positioning belt with a width of 2-3mm and a surface with a laser-etched millimeter-level positioning cross mark. Among them, the composite functional area accounts for 93% of the total surface area, and the non-functional area is a ring-shaped positioning belt with a width of 2.5mm. A 355nm ultraviolet laser is used to etch a cross mark with a depth of 20μm (line width 0.1mm, spacing 1mm), which is combined with the fluorescent layer to achieve double-stage positioning.

[0034] (8) After 500 hours of UV aging test according to ISO4892-3 standard, the water contact angle of the hydrophobic area decays ≤8° and the rolling angle ≤10°; the anti-fog performance of the hydrophilic area is maintained for ≥1200 hours without fogging in an environment with a sudden temperature change of 50°C to -20°C. Among them, the UV aging test according to ISO 4892-3 standard (0.55W / m 2 @340nm, blackboard temperature 60°C): After 500 hours, the contact angle of the hydrophobic area decreased from 158° to 152°, and the sliding angle was 9.8°. After the hydrophilic area was sprayed with 50°C hot water vapor (temperature difference 70°C) in a -20°C cold storage, the anti-fog time was maintained for >1300 hours (fogging area <5%).

[0035] (9) The hexagonal hydrophobic unit area accounts for 60%-70%, and the surface of the grid-like hydrophilic area is provided with a micropore array with a depth of 0.1-0.5 μm and a diameter of 2-5 μm, and a porosity of 15%-25%, so that the water vapor diffusion rate reaches 0.8-1.2 g / (m 2 ·h), where the hexagonal hydrophobic unit area accounts for 65%, and the hydrophilic grid surface micropores are formed by hot pressing of a nanoimprint template (period 5μm, protrusion height 0.4μm). The water vapor diffusion rate is 1.05g / (m 2 h) (GB / T 17146-2015 cup method, 38°C / 90% RH conditions).

[0036] (10) In the environmental test with a vehicle speed of ≥80 km / h, the retention time of rainwater on the membrane surface is ≤0.5 seconds, the anti-fog response time is ≤3 seconds (relative humidity 90% to 20% sudden change condition), and the optical distortion value Δn ≤0.001. Among them, the wind tunnel test (wind speed 22.2 m / s≈80 km / h): the average retention time of surface water droplets (particle size 2 mm) is 0.42 seconds; humidity sudden change test (from 90% to 20% RH): the membrane surface is completely clear in 2.7 seconds; the optical distortion Δn = 0.0008 (ISO 13666 standard laser interferometry method).

[0037] Example 2: Multi-source data joint modeling scenario

[0038] 1. Substrate pretreatment

[0039] Step 1.1 Substrate cutting and cleaning

[0040] A biaxially stretched PET roll (model ST504, thickness 100 μm) was cut into 1.2 m × 0.8 m sheets using a CNC slitting machine in a constant temperature and humidity chamber (23°C ± 2°C, 45% RH ± 5%). The surface was wiped three times in one direction with a dust-free cloth dipped in isopropyl alcohol to remove grease.

[0041] Stable environmental temperature and humidity prevent deformation of the membrane material; isopropyl alcohol dissolves organic pollutants to ensure subsequent adhesion.

[0042] Key points: Slitting accuracy ±0.5mm, surface residual particles ≤5 pieces / m2 (ISO 14644-1 standard).

[0043] Step 1.2 Plasma surface activation

[0044] The sheet was placed in a vacuum chamber (pressure 10 Pa), oxygen was introduced at 200 standard cubic centimeters per minute (sccm), and a 13.56 MHz radio frequency source (power 300 W) was turned on for 30 seconds. After being taken out, the sheet was entered into the next process within 10 minutes.

[0045] Oxygen plasma bombards the PET surface to generate free radicals, forming hydroxyl (-OH) active groups, and the surface energy is increased to above 72mN / m.

[0046] Verification: add 1μL of deionized water, and the spreading angle is ≤10°, which is qualified (if >10°, rework is required).

[0047] 2. Production of hydrophobic rainproof layer

[0048] Step 2.1 Coating solution preparation

[0049] 15 parts by weight of fluorosilicone (Shin-Etsu KF-96), 5 parts by weight of hydrophobic silica nanoparticles (Evonik AEROSILR8200, particle size 50 nm), and 80 parts by weight of ethanol were added to a ball mill and ball milled at 300 rpm for 2 hours until the particle size distribution D90 was ≤ 100 nm.

[0050] The shear force of ball milling broke up the agglomeration of nanoparticles, and the viscosity of the ethanol solvent was controlled at 35±5 mPa·s (25°C).

[0051] Step 2.2 Nanoimprint Molding

[0052] First, the nickel template (regular hexagonal array, unit diameter 1.0mm, spacing 2.5mm) was preheated to 80°C, and then the slit coater evenly coated the coating liquid on the substrate at a speed of 5 meters per minute (wet film thickness 8μm). The template was pressed with a pressure of 0.8 MPa and separated after holding the pressure for 10 seconds. Finally, it was cured by hot air circulation at 80°C for 10 minutes.

[0053] The pressure causes the coating liquid to fill the microcavities of the template, and after solidification, a 2.5 μm thick hydrophobic layer is formed.

[0054] Verification: Contact angle ≥158° (GB / T 30447-2013), re-coat unqualified areas.

[0055] 3. Production of hydrophilic anti-fog layer

[0056] Step 3.1 Preparation of hydrophilic slurry

[0057] 20 parts by weight of polyvinyl pyrrolidone (PVP K30), 8 parts by weight of titanium dioxide-silica sol (DuPont TYZOR), and 72 parts by weight of deionized water were magnetically stirred at 40° C. for 1 hour, and the viscosity was controlled to 20±3 mPa·s after filtering and removing bubbles.

[0058] Step 3.2 Micro-pit structure forming

[0059] First, the slurry was coated on the hydrophobic layer grid area (wet film thickness 5 μm) using a Mayer rod, and then the wet film was rolled using a microneedle roller (needle diameter 3 μm, needle height 0.4 μm) at a pressure of 0.3 MPa and a speed of 3 meters per minute. Finally, it was dried at 60°C for 20 minutes to form a hydrophilic layer with a solid content of 100% and a thickness of 1.2 μm.

[0060] The needle tip presses into the wet film to form micropores, increasing the specific surface area by 3 times (SEM detection).

[0061] Parameter: Porosity = (total volume of pits / volume of hydrophilic layer) × 100%, controlled at 20% ± 2%.

[0062] 4. Gradient transition layer deposition

[0063] Step 4.1 Vapor Deposition Algorithm Execution

[0064] The substrate was placed on a PECVD heating stage (150°C). The time variable t (0-300 seconds) was set, and gases were dynamically introduced according to the following algorithm: hexamethyldisiloxane (HMDSO) flow rate = 100-0.3×t (unit: sccm); oxygen (O2) flow rate = 10+0.1×t (unit: sccm). The plasma was excited at a 200W RF power for 5 minutes, where t is the real-time process time (seconds); 0.3 is the HMDSO attenuation coefficient per second (to ensure a linear decrease in fluorine concentration); 0.1 is the O2 enhancement coefficient per second (to promote oxidation reaction);

[0065] Output: 20μm wide transition region, XPS detected fluorine atomic concentration dropped from 88% to 6%.

[0066] 5. Addition of functional enhancement layer

[0067] Step 5.1 Fluorescent positioning layer printing

[0068] First, europium-doped yttrium vanadate phosphor (15 g) and PMMA resin (85 g) were ball-milled in 300 g of ethyl acetate to a particle size of ≤5 μm. Then, a 250-mesh screen was used to cover a 2.5 mm wide area at the edge of the film. The scraper was printed at a pressure of 0.25 MPa and a speed of 0.5 m / min. Finally, the film was cured at 80°C for 15 minutes to form a 10 μm thick fluorescent layer.

[0069] Detection: emits green light (peak 542nm) under 365nm ultraviolet light, brightness ≥350 candela per square meter (cd / m 2 ).

[0070] Step 5.2 Pressure-sensitive adhesive lamination

[0071] Glue formula: 40 parts by weight of acrylate copolymer + 0.5 parts by weight of glass microspheres (diameter 3 μm) + 0.3 parts by weight of isocyanate crosslinker.

[0072] The release film was coated with glue using a comma scraper (wet film thickness 110 μm), and cured at 120° C. for 3 minutes to obtain a dry glue thickness of 50 μm, which was then rolled and laminated to the functional layer under a pressure of 0.5 MPa.

[0073] Glass beads act as spacers to prevent over-pressure of the adhesive layer and ensure uniform thickness.

[0074] 6. Post-processing and testing

[0075] Step 6.1 Laser positioning marking

[0076] A UV laser (wavelength 355 nm) was used to etch a crosshair on the edge of the film. The parameters were:

[0077] Pulse energy: 0.1 mJ;

[0078] Scanning speed: 500 mm per second;

[0079] Engraving depth: 20 microns (μm);

[0080] Line width: 0.1 mm, spacing 10 mm;

[0081] Verification: The position deviation of the marking line measured under a microscope is ≤±0.05mm.

[0082] Step 6.2 Comprehensive performance test

[0083] Rainproof test: The wind tunnel is adjusted to 22.2 meters per second (simulating a vehicle speed of 80 kilometers per hour), the nozzle sprays water droplets with a diameter of 2 mm (flow rate of 2 liters per minute), and the high-speed camera (1000 frames per second) records the water droplet residence time: ≤0.5 seconds to pass.

[0084] Anti-fog test: The film is covered on a -20℃ metal table, and saturated water vapor at 50℃ is sprayed for 5 seconds at a distance of 10 cm from the surface. The time it takes for the film surface to become completely clear is recorded. If it is ≤3 seconds, it is a pass.

[0085] Aging test: 500 hours of UV aging (0.55 watts per square meter @ 340nm) according to ISO 4892-3 standard, contact angle decay detection: ≤8° is qualified (initial value 158°).

[0086] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense, and may refer to mechanical or electrical connections, internal communication between two components, or direct connection. "Up," "down," "left," and "right" are only used to indicate relative positional relationships. When the absolute positions of the objects being described change, the relative positional relationships may also change.

[0087] Secondly: The drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures may refer to conventional designs. The same embodiment and different embodiments of the present invention may be combined with each other without conflict.

[0088] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A rainproof and fogproof film for a vehicle, characterized in that: It includes a transparent flexible substrate, the surface of which is divided into a hydrophobic rainproof layer and a hydrophilic anti-fog layer; the hydrophobic rainproof layer is composed of a nano-scale hydrophobic material and has a water contact angle of ≥150°, and the hydrophilic anti-fog layer is composed of a hygroscopic polymer material and has a water contact angle of ≤30°; the two are formed into a composite functional area with a preset array arrangement through micro-nano processing, wherein the hydrophobic rainproof layer is a hexagonal unit with a diameter of 0.5mm-1.5mm, and the hydrophilic anti-fog layer constitutes a connected grid with a width of 50μm-200μm between units, and the center distance between adjacent hydrophobic units is 1.8-3.2 times the diameter of the unit circumscribed circle.

2. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: The hydrophobic rainproof layer has a thickness of 0.5-5 μm and is composed of a compound of fluorinated silicone and silica nanoparticles in a mass ratio of 3:1-5:1, with a nanoparticle size of 20-100 nm; the hydrophilic anti-fog layer has a thickness of 0.2-2 μm and is composed of a compound of polyvinyl pyrrolidone and titanium dioxide-silica sol in a ratio of 1:0.3-1:0.6, and its surface has a micron-scale pit structure to enhance water vapor adsorption capacity.

3. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: A transition structure with a gradual composition gradient is provided at the junction of the hydrophobic rainproof layer and the hydrophilic anti-fog layer. This structure is formed by plasma-assisted vapor deposition. The width of the transition zone is 10-30 μm, and the fluorine content linearly decreases from 90 at% to 5 at%, and the oxygen content increases from 5 at% to 45 at%, so that the interlayer peeling strength reaches 8-12 N / cm.

4. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: The edge of the composite functional area is integrated with a fluorescent positioning layer, which is composed of europium-doped yttrium vanadate phosphor and polymethyl methacrylate in a mass ratio of 1:9-2:8, with a thickness of 5-15μm. It emits green fluorescence with a peak of 542nm under 365nm ultraviolet light excitation, and a brightness of ≥300cd / m 2 .

5. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: The transparent flexible substrate is a biaxially stretched polyethylene terephthalate film with a thickness of 50-150 μm, and the surface is treated with oxygen plasma to a roughness Ra of 0.05-0.2 μm; the overall visible light transmittance of the film is ≥92%, the haze is ≤1.5%, and the ultraviolet blocking rate is ≥99%.

6. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: The back of the film is provided with a pressure-sensitive adhesive layer and a release film in sequence. The pressure-sensitive adhesive layer is a cross-linked acrylic copolymer with a thickness of 25-100 μm and contains glass microbead spacers with a particle size of 1-5 μm. Its 180° peel strength is 8-15 N / cm, the stickiness is greater than 72h / 1kg, and the moisture and heat resistance meets the requirements of no falling off for 500 hours under an environment of 85°C / 85% RH.

7. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: The composite functional area accounts for 90%-95% of the total surface area of ​​the membrane, and the non-functional area is a surrounding installation positioning belt with a width of 2-3mm and a surface with a laser-etched millimeter-level positioning cross mark.

8. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: After 500 hours of UV aging test according to ISO4892-3 standard, the water contact angle of the hydrophobic area decays ≤8° and the rolling angle ≤10°; the anti-fog performance of the hydrophilic area remains fog-free for ≥1200 hours in an environment where the temperature suddenly changes from 50°C to -20°C.

9. The rainproof and fogproof film for vehicles according to claim 2, characterized in that: The hexagonal hydrophobic unit area accounts for 60%-70%, and the surface of the grid-like hydrophilic area is provided with a micropore array with a depth of 0.1-0.5 μm and a diameter of 2-5 μm, with a porosity of 15%-25%, so that the water vapor diffusion rate reaches 0.8-1.2 g / (m 2 ·h).

10. The rainproof and fogproof film for vehicles according to claim 1, characterized in that: In the environmental test with a vehicle speed of ≥80km / h, the rainwater retention time on the membrane surface is ≤0.5 seconds, the anti-fog response time is ≤3 seconds (relative humidity 90% to 20% sudden change condition), and the optical distortion value Δn is ≤0.001.

Images