An easily-removed airport pavement marking line structure and a preparation method and a removal method thereof

Abstract

This invention discloses an easily removable airport pavement marking structure, its preparation method, and its removal method. The marking structure is a two-layer composite structure, comprising, from bottom to top, a water-based sealing primer layer adhered to the pavement substrate surface and a functional topcoat layer bonded thereon. The functional topcoat layer is an A / B two-component coating, where component A contains hydroxyl acrylic resin, methyldiethanolamine, polyethylene glycol, and nano-silica modified with a silane coupling agent. During removal, a weakly acidic paint remover is sprayed, and the methyldiethanolamine undergoes a protonation reaction, inducing the swelling and peeling of the functional topcoat layer. This invention, through the interfacial barrier of the sealing primer layer and the synergistic response mechanism of methyldiethanolamine and polyethylene glycol, combined with the enhancement modification of nano-silica, enables the markings to possess excellent wear resistance and anti-slip properties during service. Removal requires only mild conditions and can achieve a peeling rate of ≥95% in a very short time, without damaging the pavement substrate or polluting the environment.

Description

Technical Field

[0001] This invention belongs to the technical field of airport pavement engineering and traffic marking materials, specifically relating to an easy-to-remove airport pavement marking structure and its preparation and removal methods. Background Technology

[0002] Airport runway and taxiway markings are core infrastructure ensuring aircraft ground operation safety and providing visual navigation aids. Their integrity and functionality directly determine the safety performance of aircraft takeoffs, landings, and taxiing. With the rapid development of modern civil aviation and the frequent takeoffs and landings of heavy-duty aircraft, airport pavements not only need to withstand high-frequency impact loads from aircraft, but the marking systems on these pavements also face harsh service environments. To ensure that the markings maintain their prescribed road performance under complex external conditions such as aircraft tire friction and high exhaust temperatures, airport pavement marking materials should possess high structural strength and interfacial adhesion.

[0003] However, in the actual operation and life-cycle maintenance of airports, the high adhesion of pavement markings and the frequent need for removal in actual engineering projects constitute an irreconcilable technical contradiction. Airports need to carry out pavement marking removal work in the following two situations: first, the marking thickness exceeds the standard; second, the markings need to be changed due to airport expansion or taxiway optimization. Statistics show that the area of ​​marking removal and renovation projects at a single airport can reach several thousand square meters. If the old markings are not thoroughly removed, they will create cluttered visual guidance signals, seriously interfering with pilots' judgment, and may also cause newly applied markings to detach due to uneven bottom surfaces and poor adhesion. Therefore, how to efficiently and without damage remove old markings has always been a key technical challenge that urgently needs to be overcome in the field of airport pavement maintenance.

[0004] Currently, environmentally friendly pavement marking paints, such as acrylic paints, are widely used in civil airports. However, from the perspective of materials chemistry and interfacial mechanics, during the film-forming and curing process of existing pavement marking paints, polymer particles undergo a strong cross-linking reaction, forming a dense network structure. Simultaneously, the polar functional groups in the paint undergo deep physical and chemical bonding with the micropores of the cement concrete pavement, producing a very strong anchoring effect. While this material design concept greatly improves the durability of the markings, because it does not reserve any easily removable functional sites at the molecular structure level, once the markings are formed, their interfacial bonding energy is extremely high, making them highly resistant to external damage and often difficult to remove when needed.

[0005] To remove the aforementioned high-adhesion road markings, existing engineering methods primarily rely on physical destruction, including mechanical grinding, shot blasting, sandblasting, and high-pressure water jet removal. However, these methods have all revealed significant drawbacks in practical applications. Firstly, mechanical grinding is currently one of the most commonly used physical removal methods. This method uses a high-speed rotating carbide cutter or steel wire to forcibly cut the road marking coating. Because mechanical cutting cannot accurately perceive the thickness of the road markings and the microscopic undulations of the pavement surface, it inevitably cuts away a certain depth of the pavement surface structure while scraping off the markings. For cement concrete pavements, this rigid impact not only damages the surface texture but also easily induces microcracks within the pavement; for asphalt pavements, it directly leads to the stripping of coarse aggregate. This structural damage is highly likely to develop into potholes, loosening, and other defects during subsequent service. If the debris from the damage is not thoroughly cleaned, it can easily form foreign object debris (FOD), which, if ingested into aircraft engines or punctured aircraft tires, will cause catastrophic aviation safety accidents. Secondly, shot blasting has been commonly used in airports for many years due to its relatively high cleaning efficiency. However, shot blasting poses serious safety hazards; the residual shot can damage aircraft under the influence of engine airflow. Therefore, airports are extremely cautious about shot blasting for line removal. Furthermore, sandblasting generates significant dust pollution during operation, severely impacting air quality and visibility around airports, and the mixed waste produced is difficult to classify and recycle.

[0006] In recent years, high-pressure or ultra-high-pressure water jet cleaning technology has been increasingly widely used. Studies have shown that at a controlled water pressure of 62 MPa, the single-shot removal effect of high-pressure water jets is poor, with uneven paint peeling. Increasing the water pressure to 68 MPa improves the single-shot removal effect, but still fails to completely remove the marking paint, and even results in some aggregate detachment from the cement pavement. This demonstrates that high-pressure water jets still cannot fundamentally solve the technical problem of damaging the original pavement surface.

[0007] In addition, chemical removal methods utilize the solvents in paint removers to swell and peel off the marking coating. However, traditional paint removers release large amounts of solvents that pollute the construction environment, easily causing poisoning and fires, making them unsuitable for large-scale use. More importantly, the existing highly cross-linked acrylic marking coating has a dense and hydrophobic structure, making it difficult for conventional paint removers to penetrate effectively, resulting in extremely limited removal effects.

[0008] In summary, current technologies for removing airport pavement markings rely on material developers focusing solely on improving the adhesion and abrasion resistance of the markings, while equipment manufacturers resort to higher water pressure and stronger cutting forces forcibly removal. This disconnect between marking material design and removal processes is the root cause of the significant damage, low efficiency, heavy pollution, and high costs associated with marking removal. It no longer meets the technological needs of current refined airport pavement maintenance decisions.

[0009] Therefore, it is urgent to break away from the traditional one-way technological thinking and develop a new type of airport pavement marking system from the perspective of systems engineering and material interfaces. This system needs to incorporate environmental response or interface weakening mechanisms under specific conditions from the initial material design stage, so that it has excellent physical and mechanical properties in normal service environments, and can quickly undergo interface desorption or coating fragmentation when faced with specific and mild removal conditions, thereby achieving rapid removal of the markings with low energy consumption, high efficiency and zero damage to the pavement. Summary of the Invention

[0010] To address the shortcomings of existing technologies, this invention provides an easy-to-remove airport pavement marking structure, its preparation method, and its removal method. By utilizing the interfacial barrier of the sealed primer layer and the synergistic response mechanism of methyl diethanolamine and polyethylene glycol in the functional topcoat layer, supplemented by the reinforcement modification of nano-silica, the airport pavement markings achieve excellent wear resistance and anti-slip performance during service. At the same time, when removal is required, only mild conditions are needed to achieve an extremely high desorption and peeling rate in a very short time, without damaging the pavement substrate or polluting the environment.

[0011] This invention is achieved through the following technical solution:

[0012] An easy-to-remove airport pavement marking structure, wherein the marking structure is a double-layer composite structure, comprising, from bottom to top:

[0013] A sealing primer layer adhered to the surface of the pavement substrate; and,

[0014] A functional topcoat layer is bonded to the aforementioned sealing primer layer;

[0015] The sealing primer layer is a water-based transparent sealing primer, used to penetrate and seal the micropores on the surface of the pavement substrate to form an interface barrier.

[0016] The functional topcoat layer is an AB two-component acrylic polyurethane coating. Component A contains hydroxyl acrylic resin, methyl diethanolamine, polyethylene glycol, and nano-silica modified with a silane coupling agent. The functional topcoat layer has interlayer adhesion to the sealing primer layer, and when in contact with an acidic paint remover, the tertiary amine groups of the methyl diethanolamine undergo a protonation reaction, causing the functional topcoat layer to swell and peel off.

[0017] Preferably, by weight, component A of the functional topcoat layer comprises: 55-70 parts of hydroxyl acrylic resin, 1-4 parts of methyl diethanolamine, 1-3 parts of polyethylene glycol, 15-22 parts of titanium dioxide, 1.0-1.5 parts of nano silica, 0.3-0.8 parts of silane coupling agent, 5-10 parts of butyl acetate, 3-8 parts of xylene, 0.5-1.2 parts of dispersant, 0.1-0.4 parts of leveling agent, and 0.1-0.4 parts of defoamer; component B of the functional topcoat layer comprises 30-35 parts of HDI trimer.

[0018] Preferably, the mass ratio of component A to component B is 100:35.

[0019] Preferably, the particle size of the nano-silica is 1 μm; the silane coupling agent is KH-570 containing methacryloxy group.

[0020] Preferably, the thickness of the functional topcoat layer is 0.6~0.8 mm.

[0021] Preferably, component A of the functional topcoat layer is prepared according to the following method:

[0022] Step 1) Mix butyl acetate and xylene, then add methyl diethanolamine and stir at 40-45°C until completely dissolved to form a blended solvent system;

[0023] Step 2) Add dispersant and silane coupling agent to the blended solvent system obtained in Step 1), stir, add nano silica in batches, and then perform high shear dispersion treatment to obtain nano pre-dispersed slurry;

[0024] Step 3) Add hydroxyl acrylic resin to the nano pre-dispersed slurry obtained in step 2) and stir to mix evenly, then add titanium dioxide for high-speed dispersion;

[0025] Step 4) Add leveling agent and defoamer to the slurry dispersed in step 3), stir and mix evenly to obtain the final product.

[0026] The above-mentioned method for removing easily removable airport pavement markings includes the following steps:

[0027] Step 1) Perform micro-abrasive polishing pretreatment on the surface of the functional topcoat layer to increase the specific surface area of ​​the functional topcoat layer;

[0028] Step 2) Spray an acidic paint remover onto the surface of the functional topcoat layer after the micro-sanding pretreatment, so that the acidic paint remover penetrates into the interior of the functional topcoat layer and undergoes a protonation reaction with the tertiary amine group of methyl diethanolamine, inducing the functional topcoat layer to swell, curl and peel off.

[0029] Step 3) Collect the residue of the peeled functional topcoat layer.

[0030] Preferably, the depth of the minimally invasive grinding pretreatment in step 1) only reaches the functional topcoat layer and does not touch the sealing primer layer and the pavement substrate.

[0031] Preferably, the acidic paint remover in step 2) is a compound solution containing 5% to 10% by mass of weak acid components; the functional topcoat layer swells and peels off within 6 to 18 minutes after contacting the acidic paint remover.

[0032] Preferably, in step 3), the residue of the peeled functional topcoat layer is collected by low-pressure water rinsing or mechanical cleaning; the single-time peeling rate of the functional topcoat layer is ≥95%; the sealing primer layer remains on the surface of the pavement substrate after the functional topcoat layer is peeled off, and is used to directly reapply a new functional topcoat layer on it.

[0033] The beneficial effects of this invention are as follows:

[0034] (1) This invention adopts a two-layer composite structure design of "water-based sealing primer + functional topcoat". The water-based sealing primer can fully penetrate and fill the micropores on the surface of the pavement substrate and cure and seal it. At the micro level, it cuts off the path for the functional topcoat layer to penetrate into the deep layer of the substrate, forming an effective interface barrier. This design ensures that there is no direct physical anchoring or chemical bonding between the functional topcoat layer and the pavement substrate, providing a structural basis for subsequent rapid and non-destructive removal.

[0035] (2) This invention introduces methyl diethanolamine (MDEA) containing tertiary amine groups as an environmental response target in the functional topcoat layer, and simultaneously introduces polyethylene glycol (PEG-400) to construct nanoscale hydrophilic microchannels in a hydrophobic acrylic polyurethane crosslinking network. The hydrophilicity of the PEG segments allows the weakly acidic paint remover to be rapidly and directionally transported to the MDEA nodes inside the coating through capillary pumping. The tertiary amine groups of MDEA undergo targeted protonation reactions with hydrogen ions, causing the polymer segments to rapidly transform from a hydrophobic state to a superhydrophilic state, inducing huge water absorption and swelling stress inside the coating, thereby breaking the original mechanical balance of the coating and causing the coating to self-destructively curl and disintegrate. The synergistic effect of MDEA and PEG-400 allows the coating to undergo large-area swelling and peeling in a very short time after contact with the paint remover, and the single-time peeling rate is ≥95%, which greatly improves the removal efficiency. The dosage of MDEA shows good removal response within a certain range, and with the increase of MDEA content, the removal response time is further shortened and the peeling rate is further improved.

[0036] (3) In this invention, nano-silica modified with a silane coupling agent is added to the functional topcoat layer. The nano-SiO2 can form hydrogen bonds and physical crosslinks with the acrylic macromolecular segments to form a dense network structure, which significantly improves the surface hardness and scratch resistance of the topcoat. At the same time, the micro-nano-scale rough structure formed by it gives the marking surface good anti-slip performance. All embodiments show good wear resistance. Among them, the wear resistance is significantly better than that of traditional markings when the MDEA content is low to moderate. Even when the MDEA content is high, an acceptable wear resistance level can still be maintained, ensuring that the marking has good wear resistance and anti-slip safety performance during service.

[0037] (4) The VOC content of the marking material prepared by this invention is low, far lower than that of traditional markings, which meets the requirements of green environmental protection; the drying time is short and the construction efficiency is high; the water resistance, alkali resistance, low temperature crack resistance and artificial accelerated weathering resistance tests are all normal, which proves that the introduction of MDEA and PEG hydrophilic channels does not sacrifice the daily service durability of the coating. The marking can still maintain long-term stable road performance under harsh environment, realizing the performance unity of "high wear resistance during service and easy peeling during removal" of the marking, fundamentally solving the technical contradiction between high adhesion and easy removal of airport pavement markings.

[0038] (5) The removal method of the present invention, which is compatible with the pavement marking structure, only requires micro-invasive grinding pretreatment of the functional paint layer surface and spraying with a weak acid paint remover to achieve rapid swelling and peeling of the markings. The entire removal process does not rely on high-pressure water jets, heavy-duty milling, or other high-intensity physical means. After removal, the pavement area has minimal height difference, fully meeting the airport pavement acceptance standards; the pavement strength retention rate and BPN anti-skid retention rate are both extremely high; the microscopic morphology shows that the pavement aggregate and cement mortar texture are intact, without chemical corrosion or physical cutting marks. The present invention fundamentally eliminates structural damage to the pavement substrate caused by the removal operation, avoids the risk of subsequent defects such as potholes and loosening caused by pavement damage, and FOD safety hazards, significantly improving the safety of airport pavement maintenance operations.

[0039] (6) In the removal method of the present invention, the sealing primer layer remains intact in the micropores on the surface of the pavement substrate after the functional topcoat layer is peeled off. The retained sealing primer layer can be directly used as the bottom layer of the new markings, and the pavement does not need to be subjected to deep base surface sandblasting or shot blasting again. After the surface dries, the new functional topcoat layer can be directly repainted in situ, realizing rapid in-situ renewal of the markings and significantly shortening the construction time during the airport's nighttime closure window.

[0040] (7) This invention eliminates the large amount of dust pollution generated by traditional mechanical cleaning and sandblasting methods, as well as the water and energy consumption of high-pressure water jetting. The cleaning process only requires spraying a small amount of weak acid paint remover in conjunction with low-pressure water rinsing or mechanical sweeping and collection. It has the advantages of low construction noise, no dust pollution, easy centralized recycling and treatment of waste, and low VOC content, which fully meets the development requirements of green airport and environmentally friendly maintenance. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the easy-to-remove airport pavement marking structure of the present invention;

[0042] In the diagram: 1. Airport cement concrete pavement substrate; 2. Sealing primer layer; 3. Functional topcoat layer. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to specific embodiments.

[0044] Unless otherwise specified, the technical means used in the following embodiments are all conventional means well known to those skilled in the art, and the experimental methods without specific conditions are all conventional methods in the art.

[0045] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0046] Example 1

[0047] 1. Easy-to-remove airport pavement marking structure

[0048] This embodiment provides an easy-to-remove airport pavement marking structure, such as... Figure 1 As shown, the marking line structure is a double-layer composite structure, which includes, from bottom to top, a sealing primer layer 2 attached to the surface of the airport cement concrete pavement substrate 1 and a functional topcoat layer 3 bonded to the sealing primer layer 2.

[0049] The sealing primer layer is a water-based, transparent sealing primer that penetrates into the micropores on the pavement substrate surface and cures to form a dense interfacial barrier layer. This effectively cuts off the penetration path of the functional topcoat layer into the deep pores of the substrate at the microscopic level. This sealing primer layer is chemically inert to the weakly acidic paint remover used in the subsequent cleaning process, effectively preventing the paint remover from penetrating downwards and protecting the pavement substrate from chemical corrosion.

[0050] The functional topcoat is a two-component acrylic polyurethane coating. Component A contains hydroxyl acrylic resin, methyl diethanolamine (MDEA), polyethylene glycol (PEG-400), and nano-silica modified with the silane coupling agent KH-570. Component B is an HDI trimer. After crosslinking and curing, components A and B form a coating with high crosslinking density. The tertiary amine groups of MDEA act as environmental response targets, uniformly distributed in the polymer crosslinking network. PEG-400 constructs nanoscale hydrophilic microchannels within the hydrophobic acrylic polyurethane network. Nano-silica undergoes hydrogen bonding and physical crosslinking with acrylic macromolecular segments, forming a dense, reinforced network structure. High-strength interlayer adhesion is achieved between the functional topcoat and the sealing primer layer through interlayer chemical bonding and intermolecular forces.

[0051] When this functional topcoat comes into contact with a weakly acidic paint remover, the hydrophilic microchannels of the PEG layer generate a capillary pumping effect, rapidly introducing the paint remover into the coating. The tertiary amine groups of MDEA undergo a targeted protonation reaction with hydrogen ions, inducing the functional topcoat layer to swell, curl, and peel off. The thickness of the functional topcoat layer is 0.6–0.8 mm, and the surface anti-slip value (BPN) is 45–55.

[0052] 2. Preparation of Component A of Easy-to-Clean Functional Topcoat

[0053] Prepare the following raw materials in parts by weight: 62 parts hydroxyl acrylic resin, 2.5 parts MDEA, 2 parts PEG-400, 18 parts titanium dioxide R902, 1.2 parts nano silica (particle size 1 μm), 0.5 parts KH-570 coupling agent, 8 parts butyl acetate, 5 parts xylene, 0.8 parts BYK-163 dispersant, 0.2 parts BYK-333 leveling agent, and 0.2 parts silicone defoamer.

[0054] The preparation of component A of the functional topcoat is carried out according to the following steps:

[0055] (1) Pre-dissolution of blended solvent and functional monomer

[0056] Butyl acetate and xylene were added to a stainless steel reactor equipped with a temperature control system. The reactor was stirred at a low speed of 300-500 r / min. Then MDEA was added, and the reactor was heated in a water bath at 40-45℃ with continuous stirring until the solid was completely dissolved, forming a homogeneous and transparent blended solvent system.

[0057] (2) In-situ modification and pre-dispersion of nanoparticles

[0058] The reactor temperature was lowered to room temperature. BYK-163 dispersant and KH-570 coupling agent were added sequentially to the above solution, and the mixture was stirred for 5 minutes. Then, a high-speed disperser was started, and the rotation speed was increased to 1000 r / min. Nano-silica was slowly sieved in batches. After the addition was complete, the rotation speed was increased to 2500~3000 r / min, and high-shear dispersion was performed for 30 minutes to ensure that the coupling agent fully coated and modified the surface of the nano-silica, resulting in a nano-predispersed slurry.

[0059] (3) Grinding of base resin and pigment

[0060] Add hydroxyl acrylic resin to the above nano pre-dispersed slurry and stir at 800~1000 r / min for 10 min until it is uniformly mixed; then add titanium dioxide and increase the speed to 2000 r / min again for high-speed dispersion for 20 min. After dispersion, pour it out for later use.

[0061] (4) Additive preparation and finished product filtration

[0062] Transfer the well-ground slurry to a paint mixing tank. While stirring at low speed, slowly add BYK-333 leveling agent and silicone defoamer in sequence. After stirring continuously for 15 minutes, functional topcoat component A is obtained.

[0063] 3. Preparation of Component B

[0064] HDI trimer was used as component B, and its mass ratio with component A was A:B = 100:35.

[0065] 4. Preparation of sealing primer

[0066] The primer is a commercially available water-based epoxy floor paint that is colorless, transparent, and has high density. This primer is chemically inert to the weakly acidic paint remover used subsequently and can penetrate and seal the micropores on the surface of cement concrete pavement.

[0067] Example 2

[0068] This embodiment provides an easy-to-remove airport pavement marking structure, which is basically the same as that in Embodiment 1, except that the amount of methyl diethanolamine (MDEA) in component A of the functional topcoat layer is 1 part, as detailed below:

[0069] 62 parts hydroxyl acrylic resin, 1 part MDEA, 2 parts PEG-400, 18 parts titanium dioxide R902, 1.2 parts nano silica (particle size 1 μm), 0.5 parts KH-570 coupling agent, 8 parts butyl acetate, 5 parts xylene, 0.8 parts BYK-163 dispersant, 0.2 parts BYK-333 leveling agent, and 0.2 parts silicone defoamer.

[0070] Example 3

[0071] This embodiment provides an easy-to-remove airport pavement marking structure, which is basically the same as that of Embodiment 1, except that the amount of methyl diethanolamine (MDEA) in component A of the functional topcoat layer is 4 parts, as detailed below:

[0072] 62 parts hydroxyl acrylic resin, 4 parts MDEA, 2 parts PEG-400, 18 parts titanium dioxide R902, 1.2 parts nano silica (particle size 1 μm), 0.5 parts KH-570 coupling agent, 8 parts butyl acetate, 5 parts xylene, 0.8 parts BYK-163 dispersant, 0.2 parts BYK-333 leveling agent, and 0.2 parts silicone defoamer.

[0073] Example 4

[0074] This embodiment provides a method for on-site construction and directional removal of easily removable airport pavement markings based on the easy-to-remove airport pavement marking structure obtained in Embodiment 1. The specific steps are as follows:

[0075] 1. Marking of lane markings

[0076] (1) Pavement pretreatment

[0077] Before construction, remove dust, oil, and water from the surface of the airport's cement concrete pavement and keep the pavement dry.

[0078] (2) Apply a sealing primer layer

[0079] A layer of water-based transparent sealing primer is evenly sprayed onto the cleaned pavement surface using a spraying method. This primer penetrates into the micropores of the pavement substrate and cures to seal it, forming a dense interfacial barrier layer. Because this water-based primer is chemically inert to the organic paint remover used subsequently, it cuts off the path for solvents to penetrate deep into the concrete / asphalt at the microscopic level, perfectly protecting the pavement substrate from corrosion.

[0080] (3) Component mixing and maturation

[0081] Before construction, the components A and B prepared in Example 1 were weighed and mixed strictly according to the mass ratio of A:B=100:35. The mixture was stirred for 3-5 minutes using an electric stirrer to ensure uniform contact between the two components in the crosslinking system. After mixing, the mixture was allowed to stand for 5-10 minutes to allow air bubbles to escape from the system.

[0082] (4) Coating and film formation

[0083] High-pressure airless spraying equipment was used for application, with spray pressure and vehicle speed controlled to maintain a wet film thickness of 400–600 μm. After spraying, it cured naturally at room temperature. Due to the presence of a highly efficient catalyst and a nano-crosslinking network within the system, the coating reached surface dryness within 1 hour, and was fully open to aircraft traffic after 6 hours. The thickness of the cured functional topcoat layer was 0.6–0.8 mm.

[0084] 2. Directional removal of road markings

[0085] When an airport faces taxiway optimization, runway extension, or aging road markings that require updating, the following steps are used for removal:

[0086] (1) Surface micro-grinding pretreatment

[0087] Before applying chemical reagents, use a light sanding tool to perform micro-sanding or roughening on the surface of the old functional topcoat layer, strictly controlling the sanding depth so that it only damages the dense skin layer on the surface of the coating, without touching the bottom sealing primer layer and pavement substrate.

[0088] This step aims to significantly increase the specific surface area of ​​the topcoat layer and artificially create a large number of tiny scratches and pores on the surface of the dense coating, laying the physical foundation for the deep penetration of subsequent solvents.

[0089] (2) Spraying environmentally friendly cleaning agents

[0090] Spray a compounded, environmentally friendly paint remover and swelling agent containing 5-10% by mass of a weak acid (such as a composite of organic acids or penetrants) onto the surface of the markings to be removed. Allow it to stand for 10-20 minutes. After the weak acid solution penetrates into the coating, the hydrogen ions in the solution undergo a targeted protonation reaction with the tertiary amine groups of MDEA in the polymer crosslinking network. This reaction causes the polymer chain segments to rapidly transform from a hydrophobic state to a superhydrophilic state, inducing huge water absorption and swelling stress inside the coating. This breaks the original mechanical balance, causing the coating, which has high adhesion and high wear resistance, to self-destructively curl and disintegrate.

[0091] Because physical pretreatment significantly reduces the diffusion resistance of solvent penetration, the settling time can be shortened from the conventional 20-30 minutes to 10-20 minutes. During this period, the functional topcoat layer rapidly releases internal stress, manifesting as overall swelling, wrinkling, and peeling. Simultaneously, the underlying sealing primer layer continuously and effectively blocks solvent penetration, protecting the pavement substrate from chemical corrosion.

[0092] (3) Low-interference mechanical collection

[0093] After the surface layer is completely softened and curled, there is no need to use traditional high-pressure water guns or heavy milling machines. Only a low-frequency mechanical sweeper or a 15 MPa low-pressure water flow is needed to easily scrape off and collect the detached waste paint film. The paint film residue rate is ≤3%, the single-time desorption and peeling rate is ≥98%, and the dust pollution and hard damage to the pavement caused by the direct deep cutting of the grinding machine are completely eliminated.

[0094] (4) In-situ rapid recoating and renewal

[0095] After the old topcoat is removed, the underlying sealing primer layer remains intact in the micropores of the pavement. At this point, the pavement does not need to undergo deep surface sandblasting or shot blasting again. After the surface dries, a new functional topcoat layer can be applied directly in place, achieving a rapid renewal of the pavement markings.

[0096] The entire process of "polishing-activation-collection-recoating" can be completed within a compact 4-hour nighttime shutdown window.

[0097] Comparative Example 1

[0098] This comparative example provides a traditional, conventional marking, as follows:

[0099] Commercially available two-component acrylic polyurethane road marking paint (MDEA-free, PEG-400-free) is used, with a water-based sealing primer applied underneath. The application method is traditional mechanical sanding.

[0100] Comparative Example 2

[0101] This comparative example provides a reference system lacking a collaborative mechanism, as follows:

[0102] A topcoat system was used, consisting only of MDEA and nano-silica, but without the introduction of PEG-400 to construct hydrophilic channels. A water-based sealing primer was applied as the base coat. The remaining components and application methods were the same as in Example 4.

[0103] Test Example 1

[0104] The performance of the easy-to-remove airport pavement marking structures prepared in Examples 1-3 and the markings prepared in Comparative Examples 1 and 2 were tested, as follows:

[0105] 1. Testing Method

[0106] (1) Abrasion resistance test: In accordance with the provisions of Article 6.4.5 of the industry standard JT / T 280-2022 Road Marking Paint and GB / T1768-2006, the abrasion tester conforming to JT / T 995 was used for testing. The load weight was 1000g, the test rotation was 200 revolutions, and the abrasion weight loss value of the test block (unit: mg) was recorded.

[0107] (2) Color performance and VOC content test: Color performance was determined by using a D65 light source and 45° / 0° geometric conditions in accordance with JT / T 280-2022 Road Marking Paint to measure the luminance factor of the white coating; VOC content was determined in accordance with JT / T 1326-2020 Road Marking Materials Hazardous Substance Limits (unit: g / L).

[0108] (3) Adhesion test: Refer to Article 6.4.7 of JT / T 280-2022 Road Marking Paint, and conduct the paint film circle test according to the method specified in GB / T 1720 to evaluate the adhesion grade (level); at the same time, in order to intuitively quantify the interfacial bonding force, the pull-out method is used to test the interlayer pull-out strength (unit: MPa) between the marking coating and the cement concrete substrate.

[0109] (4) Non-stick drying time: Refer to Clause 6.4.3 of JT / T 280-2022 Road Marking Paint, and use a non-stick time tester for road marking paint that meets the requirements of JT / T 996. The test begins 10 minutes after the test plate is coated, and the time when the tire no longer sticks to the test material is recorded (unit: min).

[0110] (5) Water resistance and alkali resistance test: Referring to Articles 6.1.10 and 6.1.11 of JT / T 280-2022 Road Marking Coating, according to the methods specified in GB / T 1733 and GB / T 9265, the prepared test plates were immersed in deionized water and saturated calcium hydroxide solution for 24 h respectively, and the surface morphology of the coating was observed.

[0111] (6) Low temperature crack resistance: -10℃ for 4 h, room temperature for 4 h as one cycle, and check the crack condition after 3 consecutive cycles.

[0112] (7) Artificial accelerated weathering: Refer to Article 6.1.12 of JT / T 280-2022 Road Marking Coatings and conduct the test according to the provisions of Cycle A in GB / T1865-2009. After 600 hours of continuous testing of the two-component coating, observe the powdering, cracking and peeling of the coating.

[0113] (8) Targeted removal response time and peeling rate: Under the same room temperature conditions, spray an equal amount of weak acid environmentally friendly paint remover (8% by mass of weak acid compound solution) onto the surface of each group of test blocks, record the time required from spraying to large-area curling and softening of the coating; and after the specified time, rinse with 15 MPa low-pressure water and calculate the percentage of the area of ​​paint film peeling off.

[0114] (9) Corrosion protection and friction coefficient (BPN) retention rate of paint remover: The surface of the concrete test block with the sealing primer was immersed in the paint remover for 2 hours. After cleaning, the compressive strength retention rate (%) of the concrete and the pH value change under the interface primer were tested. The BPN retention rate of the pavement before and after the marking was removed was tested using a pendulum friction tester.

[0115] 2. Test Results

[0116] Table 1 Basic Road Performance and Environmental Performance Tests

[0117]

[0118] Table 2 Evaluation Results of Removal Efficiency and Non-destructive Protection of Pavement Substrate

[0119]

[0120] 3. Results Analysis

[0121] (1) Analysis of basic physical and environmental protection indicators

[0122] The VOC content of Examples 1-3 of this invention is all below 100 g / L, and the brightness factor is ≥0.84, meeting the requirements for green environmental protection and high reflectivity for visual navigation. The Shore D hardness of the coating is maintained between 55 and 63. Combined with nano-SiO2 modification, its actual wear resistance (weight loss ≤36.5 mg) is significantly better than that of traditional markings (Comparative Example 1). At the same time, all examples showed no abnormalities in water resistance, alkali resistance, and 600 h weathering resistance tests, proving that the introduction of MDEA and PEG hydrophilic channels did not sacrifice the daily service durability of the coating.

[0123] (2) Evaluation of cleaning efficiency and non-destructive physical properties of pavement

[0124] Addressing the critical concerns of airports regarding the removal of elevation differences and damage, Comparative Example 1 employed traditional mechanical milling. Due to the inability to precisely control the cutting depth, the elevation difference in the removed area reached -1.5 to -2.5 mm (significantly exceeding the ±1 mm acceptance standard). Furthermore, SEM morphology revealed that the pavement aggregate was fragmented and accompanied by microcracks, with the BPN anti-skid retention rate dropping to 65%. In contrast, Example 1 of this invention, leveraging the highly efficient targeted self-destruct mechanism of MDEA synergistic with PEG, achieved a peeling rate exceeding 98% within 10 minutes. After water washing, the pavement elevation difference was only +0.02 mm, meeting the acceptance standard. SEM scanning confirmed that the microstructure of the removed pavement remained intact, avoiding structural damage caused by mechanical impact.

[0125] (3) Evaluation of chemical barrier and corrosion prevention

[0126] In Examples 1-3 of this invention, after being soaked and removed with acidic paint remover, the compressive strength retention rate of the concrete pavement was all above 99.4%, and the pH value below the interface did not change significantly. This provides conclusive quantitative evidence that the underlying water-based transparent sealing primer formed a dense cross-linked isolation network, effectively cutting off the capillary penetration path of acidic solvents into the deeper layers of the pavement, and achieving low chemical corrosion during the removal process.

[0127] (4) Comprehensive evaluation of the structure-activity relationship of the formulation

[0128] In Example 2 of this invention, the MDEA content was too low (1.0 part), resulting in insufficient protonation response sites, a prolonged response time of 18 min, and a slightly larger height difference (+0.05 mm). In Example 3, the MDEA content was too high (4.0 parts), which resulted in extremely fast removal (6 min), but the coating hardness decreased to 55D, and the wear resistance weight loss increased. Example 1 (2.5 parts MDEA) showed the best formulation balance, achieving a near-perfect non-destructive removal effect while ensuring hardness and adhesion (peeling rate ≥98%, strength retention rate 99.6%, height difference +0.02 mm).

[0129] In summary, this invention achieves a high degree of uniformity in the performance of airport pavement markings, namely, "high adhesion and high wear resistance during service, and gentle and easy peeling during removal." It fundamentally solves the technical contradiction of traditional pavement markings being difficult to remove and causing significant damage, and has extremely high engineering transformation value.

[0130] The embodiments described above are only some, not all, of the embodiments of the present invention. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. The scope of protection of the present invention is determined by the scope claimed in the claims. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. An easy-to-remove airport pavement marking structure, characterized in that, The marker line structure is a double-layer composite structure, comprising, from bottom to top: A sealing primer layer adhered to the surface of the pavement substrate; and, A functional topcoat layer is bonded to the aforementioned sealing primer layer; The sealing primer layer is a water-based transparent sealing primer, used to penetrate and seal the micropores on the surface of the pavement substrate to form an interface barrier. The functional topcoat layer is an AB two-component acrylic polyurethane coating. Component A contains hydroxyl acrylic resin, methyl diethanolamine, polyethylene glycol, and nano-silica modified with a silane coupling agent. The functional topcoat layer has interlayer adhesion to the sealing primer layer, and when in contact with an acidic paint remover, the tertiary amine groups of the methyl diethanolamine undergo a protonation reaction, causing the functional topcoat layer to swell and peel off.

2. The easily removable airport pavement marking structure according to claim 1, characterized in that, By weight, component A of the functional topcoat layer comprises: 55-70 parts hydroxyl acrylic resin, 1-4 parts methyl diethanolamine, 1-3 parts polyethylene glycol, 15-22 parts titanium dioxide, 1.0-1.5 parts nano silica, 0.3-0.8 parts silane coupling agent, 5-10 parts butyl acetate, 3-8 parts xylene, 0.5-1.2 parts dispersant, 0.1-0.4 parts leveling agent, and 0.1-0.4 parts defoamer; component B of the functional topcoat layer comprises 30-35 parts HDI trimer.

3. The easily removable airport pavement marking structure according to claim 2, characterized in that, The mass ratio of component A to component B is 100:

35.

4. The easily removable airport pavement marking structure according to claim 2, characterized in that, The nano-silica has a particle size of 1 μm; the silane coupling agent is KH-570 containing methacryloxy group.

5. The easily removable airport pavement marking structure according to claim 1, characterized in that, The thickness of the functional topcoat layer is 0.6~0.8 mm.

6. A type of easily removable airport pavement marking structure according to any one of claims 1-5, characterized in that, Component A of the functional topcoat layer is prepared according to the following method: Step 1) Mix butyl acetate and xylene, then add methyl diethanolamine and stir at 40-45°C until completely dissolved to form a blended solvent system; Step 2) Add dispersant and silane coupling agent to the blended solvent system obtained in Step 1), stir, add nano silica in batches, and then perform high shear dispersion treatment to obtain nano pre-dispersed slurry; Step 3) Add hydroxyl acrylic resin to the nano pre-dispersed slurry obtained in step 2) and stir to mix evenly, then add titanium dioxide for high-speed dispersion; Step 4) Add leveling agent and defoamer to the slurry dispersed in step 3), stir and mix evenly to obtain the final product.

7. A method for removing easily removable airport pavement markings as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1) Perform micro-abrasive polishing pretreatment on the surface of the functional topcoat layer to increase the specific surface area of ​​the functional topcoat layer; Step 2) Spray an acidic paint remover onto the surface of the functional topcoat layer after the micro-sanding pretreatment, so that the acidic paint remover penetrates into the interior of the functional topcoat layer and undergoes a protonation reaction with the tertiary amine group of methyl diethanolamine, inducing the functional topcoat layer to swell, curl and peel off. Step 3) Collect the residue of the peeled functional topcoat layer.

8. The cleaning method according to claim 7, characterized in that, Step 1) The depth of the minimally invasive grinding pretreatment only reaches the functional topcoat layer and does not touch the sealing primer layer and the pavement substrate.

9. The cleaning method according to claim 7, characterized in that, Step 2) The acidic paint remover is a compound solution containing 5%~10% by mass of weak acid components; the functional topcoat layer swells and peels off within 6~18 minutes after contacting the acidic paint remover.

10. The cleaning method according to claim 7, characterized in that, In step 3), the residue of the peeled functional topcoat layer is collected by low-pressure water rinsing or mechanical cleaning; the single-time desorption and peeling rate of the functional topcoat layer is ≥95%; the sealing primer layer remains on the surface of the pavement substrate after the functional topcoat layer is peeled off, and is used to directly re-apply a new functional topcoat layer on it.

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