Plastic surface treatment process

Abstract

The invention relates to the technical field of material surface engineering, and discloses a plastic surface treatment process to solve the problems that in the prior art, a plastic surface coating is poor in adhesive force and single in function, and a traditional treatment method is not environmentally friendly. The process sequentially comprises the following steps: pre-treating a base material, and obtaining a clean and stress-free base material through ultrasonic cleaning and thermodynamic stress elimination; performing low-temperature plasma surface activation, performing physical bombardment and chemical modification on the plastic surface by utilizing plasma of specific process gas in a vacuum environment, introducing a large number of active functional groups, and remarkably improving the surface energy; and preparing and applying the functional nano coating, namely forming firm covalent bonds by using the coupling agent in a coating solution containing functional nano particles and a coupling agent and the anchor points, so that the chemical coupling of the functional coating and the plastic substrate is realized.

Description

Technical Field

[0001] This invention relates to the field of materials surface engineering technology, and in particular to a plastic surface treatment process. Background Technology

[0002] Plastics, with their advantages of being lightweight, high-strength, easy to mold, and low-cost, play an indispensable role in modern industry and daily life. From automobiles, electronics, and home appliances to medical devices and packaging materials, plastics are ubiquitous. However, many commonly used plastics (such as polypropylene (PP) and polyethylene (PE)) are non-polar polymers with low surface energy, strong chemical inertness, and poor wettability. These inherent surface characteristics often lead to problems such as coating peeling, weak adhesion, and poor ink adhesion during secondary processing such as spraying, bonding, printing, or electroplating.

[0003] To address this challenge, various methods for treating plastic surfaces have been developed. Traditional methods mainly include mechanical grinding, flame treatment, and chemical etching. While mechanical grinding can increase surface roughness, it suffers from low precision, generates dust pollution, and is ineffective on complex-shaped workpieces. Flame treatment uses a high-temperature flame to instantly oxidize the plastic surface and introduce polar groups, but the process parameters are difficult to control precisely, easily leading to overheating deformation or uneven treatment of the substrate. Chemical etching, such as using chromic acid-sulfuric acid solutions, while highly effective, uses large amounts of strong acids and heavy metal salts, generating large quantities of toxic and harmful wastewater that severely pollutes the environment. Furthermore, the process poses safety hazards, contradicting increasingly stringent environmental regulations.

[0004] In recent years, low-temperature plasma treatment technology has attracted much attention as a clean, efficient, and environmentally friendly surface modification technique. This technology utilizes high-energy particles in plasma to bombard the material surface, effectively improving its surface energy and activity without altering the substrate's intrinsic properties. After plasma treatment, the adhesion and printability of plastic surfaces are significantly improved. However, plasma treatment alone primarily addresses the underlying issue of "adhesion," ensuring that subsequent coatings can "stand firmly," but it does not directly endow plastic surfaces with specific advanced functions such as superhydrophobicity, high hardness, or antistatic properties.

[0005] On the other hand, the development of functional coating technology, especially nano-coating technology, has made it possible to endow material surfaces with specific properties. By adding functional nanoparticles to coatings, coatings with various properties can be prepared. However, if these functional coatings are directly applied to unactivated plastic surfaces, the bonding between the coating and the substrate mainly relies on physical interactions such as van der Waals forces, resulting in weak adhesion. Under long-term use or harsh environments (such as high humidity, temperature cycling, and friction), delamination and peeling are still likely to occur.

[0006] In summary, existing technologies suffer from the following drawbacks: traditional chemical treatment methods cause severe pollution; purely physical treatment methods have limited functionality or are difficult to control; and when advanced functional coating technologies are applied to low surface energy plastics, achieving a strong bond between the coating and the substrate remains a significant challenge. Therefore, there is an urgent need to develop a novel surface treatment process that is both environmentally friendly and efficient, enabling a strong bond between the functional coating and the plastic substrate, to meet the growing market demand for high-performance, high-value-added plastic products. Summary of the Invention

[0007] The purpose of this invention is to provide a plastic surface treatment process to solve the problems mentioned in the background art and facilitate its widespread application.

[0008] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0009] A plastic surface treatment process comprising four core steps: a substrate pretreatment step, a low-temperature plasma surface activation step, a functional nano-coating preparation and application step, and a coating curing and post-treatment step.

[0010] First, a substrate pretreatment step is performed. This step aims to provide a clean, stress-free, and ideal substrate for subsequent fine processing. It includes two sub-steps: precision cleaning and thermodynamic stress relief. The cleaning process uses an ultrasonic-assisted composite cleaning solution that can penetrate tiny crevices to thoroughly remove and emulsify various contaminants on the surface. Stress relief is achieved through a precisely controlled annealing process, eliminating the internal stress accumulated in the material during molding, fundamentally ensuring the dimensional stability and long-term reliability of the product.

[0011] Next, one of the core steps of this process is the low-temperature plasma surface activation step. A clean plastic substrate is placed in a vacuum environment, a specific process gas is introduced, and radio frequency or microwave energy is used to excite the gas into plasma. These highly energetic active particles exert multiple effects on the plastic surface: on the one hand, they perform nanoscale physical etching, forming a micro-rough structure and increasing the physical bonding area; on the other hand, and more crucially, they perform chemical modification, breaking the original inert chemical bonds on the surface and grafting a large number of highly reactive polar functional groups (such as -OH, -COOH, etc.). This step transforms the originally "lifeless" plastic surface into an "active interface" eager for reaction, with its surface energy increasing several times or even tens of times.

[0012] Next, another core step is performed: the preparation and application of the functional nano-coating. This step is crucial for achieving the specific functions of the final product. We first design and formulate the functional nano-coating solution according to the requirements. This solution is a complex colloidal system containing film-forming resin, functional nanoparticles, coupling agents, and solvents. For example, to achieve superhydrophobicity, fluorinated nano-silica can be used; to achieve high hardness, nano-alumina can be used. The coupling agent plays a vital "molecular glue" role; one end reacts with the nanoparticles and resin, while the other end chemically bonds with the polar functional groups on the plasma-activated substrate surface. The prepared coating solution is uniformly applied to the plasma-treated activated surface using precision spraying or other methods. Due to the time-sensitive nature of surface activation, this process needs to be completed quickly to ensure maximum chemical reaction.

[0013] Finally, the coating curing and post-treatment steps are performed. After a brief leveling process, the substrate with the wet film applied enters the main curing stage. Depending on the coating system, ultraviolet (UV) curing or thermal curing is used to cause cross-linking reactions of the resin molecules within the coating, forming a dense and robust three-dimensional network structure, while firmly "locking" the functional nanoparticles within it. After curing, the final product with fundamentally altered surface properties is obtained.

[0014] As an improvement, the beneficial effects of the present invention are as follows:

[0015] 1. Extremely high bonding strength and excellent durability: The greatest innovation of this invention lies in achieving chemical coupling between plasma activation and the functional coating. Plasma treatment creates a large number of chemical "anchor points" (active functional groups) on the substrate surface, and the coupling agent in the coating precisely covalently bonds with these "anchor points." The binding energy of this chemical bond is much greater than that of traditional physical adsorption forces (van der Waals forces), enabling the coating to fuse seamlessly with the substrate. It possesses extremely strong anti-peeling and anti-delamination capabilities, can pass the stringent cross-cut adhesion test (5B level), and maintains long-term stability under harsh environments such as humidity, temperature changes, and friction.

[0016] 2. High Customization and Versatility: This process offers high flexibility and scalability. Plasma activation, as a platform-based pretreatment step, is applicable to almost all types of plastics, including the most difficult-to-process PP, PE, and PTFE. The final surface function depends entirely on the formulation of the subsequently applied functional nano-coating. By changing different nanoparticles and resin systems, multiple functions such as superhydrophobicity, superhydrophilicity, high hardness and scratch resistance, antistatic properties, antibacterial properties, self-cleaning properties, and antireflective properties can be easily switched on the same production line to meet the customized needs of different application scenarios.

[0017] 3. The process is green and environmentally friendly, meeting the requirements of sustainable development: The core step of this invention, low-temperature plasma treatment, is a completely dry process carried out in a vacuum environment, without the use of any chemical solvents and without any wastewater or waste liquid discharge. It perfectly replaces the traditional high-pollution chemical etching process, eliminating environmental pollution at the source. In addition, the UV curing coating system used is usually a solvent-free or low-VOC (volatile organic compound) formulation, with fast curing speed and low energy consumption, further reducing the overall environmental footprint of the process.

[0018] 4. Significant Performance Improvement and High Product Added Value: This process can endow ordinary, inexpensive plastic substrates with surface properties comparable to metals, ceramics, or specialty materials. For example, it can achieve a surface hardness of 9H for PC materials, far exceeding their inherent hardness, effectively preventing scratches; and it can give PP materials a superhydrophobic effect of over 155°, providing excellent self-cleaning capabilities. This leap in performance greatly enhances product quality, lifespan, and market competitiveness, bringing higher added value to enterprises. Detailed Implementation

[0019] To make the content of this invention easier to understand, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention.

[0020] Example 1: Superhydrophobic and stain-resistant treatment of polypropylene (PP) automotive door panel interior parts

[0021] This embodiment aims to impart superhydrophobic, fingerprint-resistant, and easy-to-clean surface properties to an automotive door panel interior component injection molded from polypropylene (PP).

[0022] 1. Substrate pretreatment:

[0023] The PP door panel interior trim (approximately 400mm x 200mm x 30mm) was immersed in the cleaning solution provided in the KS-1200ST ultrasonic cleaning tank. The cleaning solution was deionized water containing 5% (wt) of nonionic surfactant (such as Triton X-100) and 2% (wt) of sodium metasilicate. Ultrasonic cleaning was performed at 55°C for 15 minutes (frequency 33kHz, power 1kW).

[0024] After removing it, rinse it with high-pressure deionized water for 5 minutes until the surface water film is uniform and unbroken, and then blow it dry with compressed clean air.

[0025] The dried workpiece is placed in a LY-6080 precision oven and heated to 70°C at a rate of 2°C / min (the Tg of PP is approximately -10°C, but the heat distortion temperature is considered here). It is then held at this temperature for 3 hours for stress relief annealing. Afterward, it is cooled to room temperature in the oven.

[0026] 2. Low-temperature plasma surface activation:

[0027] The pretreated PP workpiece is placed on the sample rack of the SAPT-P50L vacuum plasma treatment equipment (50L chamber volume).

[0028] Close the chamber door, start the vacuum system, and evacuate the chamber to a background vacuum of 4.5 Pa within 5 minutes.

[0029] The working pressure of the chamber was stabilized at 40 Pa by introducing argon (Ar) at a flow rate of 200 sccm and oxygen (O2) at a flow rate of 60 sccm through the MFC.

[0030] A 13.56MHz RF power supply was activated, set to 300W, and plasma was generated through glow discharge to treat the surface of the PP workpiece for 180 seconds. During the treatment, the workpiece surface exhibited a pale purple glow. After treatment, the power was turned off, the pressure was released, and the workpiece was removed. At this point, the surface water contact angle was measured and found to have decreased from the original 102° to approximately 35°.

[0031] 3. Preparation and application of functional nano-coatings:

[0032] Coating solution preparation: In a 10L stainless steel stirred tank, 5kg of butyl acetate was added as a solvent, followed by 1kg of fluorinated modified acrylic resin as a film-forming agent. Under low-speed stirring, 200g of hexamethyldisilazane-modified hydrophobic nano-silica (average particle size 30nm) and 50g of perfluorodecyltriethoxysilane (as a coupling agent and low surface energy agent) were slowly added. After the addition was complete, the mixture was dispersed at high speed for 30 minutes, followed by ultrasonic circulation treatment for 1 hour to obtain a uniform and stable translucent coating solution A.

[0033] Coating application: Within 5 minutes of the PP workpiece completing plasma treatment, spraying is performed using an Anben A-2000 automatic spraying robot in a Class 10,000 cleanroom. The spray gun pressure is set to 0.3 MPa, the spraying distance is 20 cm, and a uniform wet film thickness of approximately 20 μm is applied.

[0034] 4. Coating curing and post-treatment:

[0035] After spraying, allow the workpiece to stand at room temperature for 10 minutes to level.

[0036] Then it enters the UV curing tunnel via a conveyor belt. The UV light source is an LED cold light source with a main wavelength of 395nm and a light intensity of 1000mW / cm². 2 The conveyor belt speed is set to 5 m / min to ensure a total UV energy dose of approximately 300 mJ / cm². 2 .

[0037] The cured product is cooled before its performance is tested.

[0038] Performance test results:

[0039] Water contact angle: Tested using a Krüss DSA100 contact angle meter, the water droplet forms a perfect sphere on the treated surface with a contact angle of 158°±2° and a roll-off angle of less than 5°, exhibiting typical superhydrophobic properties.

[0040] Adhesion: According to ASTM D3359 standard, after tearing with 3M tape, the cut edges were intact and no cells fell off, achieving a 5B rating.

[0041] Abrasion resistance: Tested using an RCA paper tape abrasion tester under a 175g load, the surface superhydrophobic properties remained unchanged after 500 cycles (contact angle >150°).

[0042] Stain resistance: When you draw lines on the surface with an oil-based marker, the ink will shrink into individual droplets, which can be easily wiped away with a tissue without leaving any trace.

[0043] Example 2: High-hardness scratch-resistant treatment for polycarbonate (PC) mobile phone back covers

[0044] This embodiment aims to impart to a mobile phone back cover made of transparent polycarbonate (PC) injection molding a 9H pencil hardness comparable to glass and excellent scratch resistance.

[0045] 1. Substrate pretreatment:

[0046] Place the PC phone back cover in an ultrasonic cleaning tank and clean it for 10 minutes at 45°C using a deionized aqueous solution containing 3% (wt) of a special PC cleaning agent (weakly alkaline).

[0047] After rinsing and drying, the product is placed in a precision oven. The Tg of PC is approximately 145℃. The annealing process is set as follows: heat up to 120℃ at a rate of 2℃ / min, hold for 2 hours, and then cool down to room temperature at a rate of 1℃ / min.

[0048] 2. Low-temperature plasma surface activation:

[0049] The PC workpiece was placed in the same plasma device as in Example 1.

[0050] Evacuate to 5.0 Pa.

[0051] Pure nitrogen (N2) is introduced as the process gas at a flow rate of 300 sccm and a stable operating pressure of 60 Pa.

[0052] Turn on the RF power supply, set the power to 400W, and process for 120 seconds. Nitrogen plasma mainly introduces nitrogen-containing groups (such as -NH2) onto the PC surface, providing good bonding sites for subsequent coatings.

[0053] 3. Preparation and application of functional nano-coatings:

[0054] Coating solution preparation: In a reactor, 6 kg of isopropanol was added, followed by 1.5 kg of methyltrimethoxysilane and 0.5 kg of 3-glycidoxypropyltrimethoxysilane (KH-560, as a coupling agent). Under the action of an acidic catalyst (e.g., 0.1 N hydrochloric acid), the mixture was stirred and hydrolyzed for 2 hours to form an organosilicon prepolymer solution. Then, 300 g of high-purity nano-alumina (Al2O3, average particle size 20 nm) was added, and the mixture was dispersed uniformly by high-speed shearing and ultrasonic treatment to obtain a high-solids-content organic-inorganic hybrid coating solution B.

[0055] Coating application: The coating is applied using the dip-coating and pull-out method. The activated PC back cover is immersed in the coating solution B at a constant speed of 100 mm / min, held for 30 seconds, and then pulled out at a constant speed of 120 mm / min. Excess liquid flows back under gravity, forming a uniform film.

[0056] 4. Coating curing and post-treatment:

[0057] The pulled-out workpiece is pre-dried at room temperature for 15 minutes.

[0058] Then it is sent into a tunnel-type hot air circulating oven for stepped thermosetting: first, it is kept at 60°C for 20 minutes to allow the solvent to evaporate completely; then it is baked at 85°C for 45 minutes to allow the silicone coating to fully cross-link and cure.

[0059] Performance testing was conducted after cooling.

[0060] Performance test results:

[0061] Pencil Hardness: According to ASTM D3363 standard, using Mitsubishi pencils, the surface hardness of the coated surface reaches 9H, while the hardness of the untreated PC substrate is only about 2H.

[0062] Adhesion: The cross-cut adhesion test result is 5B.

[0063] Resistance to steel wool abrasion: Using 000# steel wool, under a 1kg load, after 2000 reciprocating rubs, there are no obvious scratches on the surface.

[0064] Transmittance: Spectrophotometer test showed that in the visible light range (400-700nm), the average transmittance of the PC back cover coated with the hardened layer decreased by less than 0.5% compared to the substrate, which has virtually no impact on appearance.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A plastic surface treatment process, characterized in that, This process The following steps are included and should be performed in sequence: Step 1: Substrate pretreatment step, which includes: (1) Precision cleaning: Place the plastic substrate to be treated in an ultrasonic cleaning device and use a deionized aqueous solution containing 3-8% by mass of nonionic surfactant and 1-4% by mass of alkaline detergent (such as sodium metasilicate or sodium carbonate) for ultrasonic cleaning at a temperature of 45-65℃ for 10-20 minutes to thoroughly remove oil, mold release agent, dust and other organic or inorganic contaminants from the surface of the plastic substrate. The ultrasonic frequency of the ultrasonic cleaning device is 28-40kHz and the power density is 0.5-1.5W / cm². 2 After cleaning, rinse the plastic substrate with running deionized water until the conductivity of the outflowing water is less than 5 μS / cm to ensure no cleaning agent residue remains. (2) Thermodynamic stress relief: The plastic substrate, which has been precisely cleaned and completely dried, is placed in a temperature-controlled oven and slowly heated at a rate of 1-3℃ / min to a target temperature 10-20℃ below the glass transition temperature (Tg) of the plastic substrate. The temperature is then maintained at this target temperature for 2-4 hours, and then slowly cooled to room temperature at a rate of 1-2℃ / min. This step aims to fully release the internal residual stress generated in the plastic substrate during injection molding or machining, prevent warping, cracking or deformation of the substrate due to temperature changes during subsequent processing, and improve the dimensional stability and durability of the final product. Step 2: Low-temperature plasma surface activation step; The pretreated plastic substrate is placed in the vacuum chamber of a vacuum plasma treatment device for surface activation treatment, the surface activation step including: (1) Establish a vacuum environment: Start the vacuum pump system to pump the background vacuum in the vacuum chamber to a level below 5.0 Pa in order to remove most of the non-process gas molecules in the environment and create conditions for stable plasma excitation and high-quality surface treatment. (2) Injecting and stabilizing process gas: One or more process gases are precisely injected into the vacuum chamber through a mass flow controller (MFC). The process gas is selected from argon (Ar), oxygen (O2), nitrogen (N2) or any combination of them. The volume ratio of each component in the mixture can be adjusted according to the target surface properties. After the gas pressure in the chamber stabilizes within the working pressure range of 20-80 Pa, the dynamic balance of the gas flow rate is maintained. (3) Excite the plasma and perform surface bombardment and modification: Start the radio frequency (RF) or microwave (MW) power supply to apply energy to the electrodes in the vacuum chamber, ionizing and exciting the process gas into a low-temperature plasma state; the high-energy electrons, ions, free radicals, and ultraviolet photons in the plasma physically bombard and chemically react with the surface of the plastic substrate. The mechanism of action includes: generating a nanoscale rough structure through physical bombardment, increasing the surface specific area; breaking the nonpolar chemical bonds such as CH and CC on the plastic surface, forming a large number of dangling bonds and active free radicals; simultaneously, the reaction... Plasma containing reactive gases (such as O2 and N2) grafts oxygen- or nitrogen-containing polar functional groups, such as hydroxyl (-OH), carbonyl (-C=O), carboxyl (-COOH), and amino (-NH2), onto the surface. The radio frequency power supply has a frequency of 13.56MHz, a power adjustable from 100 to 500W, and a processing time of 30 to 300 seconds. The purpose of this step is to transform the originally low surface energy and chemically inert surface of the plastic substrate into a high surface energy and chemically reactive functionalized surface, providing a foundation for the strong chemical bonding of subsequent coatings. Step 3: Preparation and application of functional nano-coating, which includes: (1) Preparation of functional nano-coating solution: A functional nano-coating solution is prepared according to the preset surface functional requirements; the core components of the solution include the following: The film-forming resin is selected from one or more of acrylic resin, epoxy resin, polyurethane resin or silicone resin; Functional nanoparticles with a particle size of 10-100 nm are selected from one or more of silicon dioxide (SiO2), titanium dioxide (TiO2), aluminum oxide (Al2O3), zinc oxide (ZnO), nano silver (Ag), or graphene. The coupling agent, selected from silane coupling agents, titanate coupling agents or aluminate coupling agents, serves to build chemical bridges between inorganic nanoparticles and organic film-forming resins, as well as between the coating and the surface of the plasma-activated plastic substrate, forming a strong covalent bond connection. Solvents and additives, wherein the solvent is an alcohol, ketone or ester solvent, and the additives include leveling agents, dispersants and defoamers; each component is mixed uniformly at low speed in a stirred tank according to a predetermined ratio, and then ultrasonically dispersed for 30-60 minutes to ensure that the nanoparticles do not agglomerate; (2) Precision application of coating: After the plastic substrate treated in step two is taken out of the vacuum chamber, it is transferred to the dust-free spraying workshop (cleanliness level of ISO7) within 10 minutes. The prepared functional nano coating solution is uniformly coated on the activated surface of the plastic substrate using high-pressure airless spraying, ultrasonic atomization spraying or dip-coating precision application method. The wet film thickness of the coating is controlled between 10-50μm to ensure that the coating is uniform, free from defects such as sagging and pinholes. Step 4: Coating curing and post-treatment steps, which include: (1) Low temperature pre-curing (leveling): Let the coated plastic substrate stand at room temperature for 5-15 minutes to allow the coating to level fully and the solvent to evaporate moderately; (2) Primary Curing: Primary curing is performed using the appropriate curing method according to the type of film-forming resin selected; if it is a photocurable system, the substrate is cured in a UV curing machine using an ultraviolet LED light source with a wavelength of 365-405nm at 100-500mJ / cm². 2 The coating is cured by irradiation under a specific energy dose; if it is a thermosetting system, it is placed in a temperature-controlled tunnel oven and baked at 60-90℃ for 30-60 minutes to allow the coating to fully cross-link and cure. (3) Quality inspection and packaging: The surface performance of the cured product is tested, including the adhesion, hardness, contact angle, wear resistance and other indicators. After passing the test, the product is finally packaged.

2. The plastic surface treatment process according to claim 1, characterized in that, The precision cleaning process in step one uses alkaline detergents such as sodium metasilicate, sodium carbonate, trisodium phosphate, or mixtures thereof. Their main function is to react with the oil stains through a saponification reaction and provide a stable alkaline buffer environment, thereby improving cleaning efficiency.

3. The plastic surface treatment process according to claim 1, characterized in that, The process gas in step two is a mixture of argon and oxygen, with oxygen accounting for 10-40% by volume. The strong physical bombardment capability of argon plasma is used to remove microscopic contaminants from the surface and create a rough structure, while the strong oxidizing property of oxygen plasma is used to efficiently introduce oxygen-containing polar functional groups into the surface. The two work synergistically to achieve a higher surface activation effect in a shorter time.

4. The plastic surface treatment process according to claim 1, characterized in that, In step three, the preparation of the functional nano-coating solution, when the target surface function is superhydrophobic and antifouling, the functional nanoparticles are nano-silica particles modified with fluorosilane, and the coupling agent is a silane coupling agent containing long-chain fluorocarbon groups, so as to construct a micro-nano dual roughness structure and a low surface energy chemical layer on the coating surface.

5. The plastic surface treatment process according to claim 4, characterized in that, In step three, when the target surface function is high hardness and scratch resistance, the functional nanoparticles are nano-alumina or nano-diamond, and the film-forming resin is a high-crosslinking density organic-inorganic hybrid silicone resin to form a dense ceramic-textured hardened layer.

6. The plastic surface treatment process according to claim 5, characterized in that, The time interval between the precise application of the coating in step three and the completion of the plasma treatment is strictly controlled within 10 minutes. This is because the surface activated by plasma has a time-dependent effect. Surface free radicals will recombine or be covered by impurities in the air over time, resulting in a decrease in activity. Therefore, the coating needs to be applied as soon as possible to ensure that the coating and the substrate form the maximum number of chemical bonds, thereby obtaining the best bonding strength.

7. The plastic surface treatment process according to claim 1, characterized in that, The plastic substrate is made of a material selected from low surface energy general-purpose plastics or engineering plastics, specifically including at least one of polypropylene (PP), polyethylene (PE), polycarbonate (PC), acrylonitrile-butadiene-styrene copolymer (ABS), polyamide (PA), or polyoxymethylene (POM).

8. The plastic surface treatment process according to claim 1, characterized in that, After the process is completed, the functional nano-coating formed on the surface of the plastic substrate has at least one of the following excellent properties: Super strong adhesion: According to the ASTM D3359 standard, the cross-cut test shows an adhesion level of 5B, meaning that the cut edges are completely smooth and no grids are detached. Water contact angle adjustability: Depending on the target function, the water contact angle of the treated surface can be less than 10° or greater than 150°; High hardness: According to the pencil hardness test of ASTM D3363 standard, the coating hardness can reach 6H or higher, and even 9H.

9. A plastic surface treatment process according to any one of claims 1 to 8, characterized in that, The article has a functional nano-coating on at least one surface that is chemically bonded to a plastic substrate. This coating imparts specific surface properties to the plastic article that are not present in traditional plastics, such as weather-resistant and stain-resistant coatings for automotive exterior parts, scratch-resistant and fingerprint-resistant coatings for consumer electronics casings, or antibacterial and biocompatible coatings for medical devices.