Wear-resistant coating for metal plate of compressed garbage truck and preparation method of wear-resistant coating

Abstract

The invention belongs to the technical field of wear-resistant coatings, and particularly relates to a wear-resistant coating for a metal plate of a compressed garbage truck and a preparation method of the wear-resistant coating. The invention aims to solve the problem that an existing coating for the metal plate of the garbage truck is difficult to keep good protection performance under corrosion and abrasion. The preparation method comprises the following steps: carrying out pre-reaction grafting modification on epoxy resin and amine-terminated polyether to obtain an epoxy prepolymer; alpha-aluminum oxide and barium sulfate are mixed, dispersed, ground and subjected to surface activation, and a basic filler is obtained; adding a mica filler into the basic filler, and shearing and mixing to obtain a composite filler; mixing the epoxy prepolymer with a phosphate auxiliary agent to obtain a primer; dispersing and mixing the epoxy prepolymer and the composite filler to obtain a functional coating; after a metal base material is subjected to sand blasting treatment, primer is pre-sprayed on the surface of the metal base material, and then functional paint is covered and sprayed to obtain the wear-resistant coating. The wear-resistant coating prepared by the invention can keep good protection performance under corrosion and wear, and has high application value.

Description

Technical Field

[0001] The invention belongs to the technical field of wear-resistant coatings, and particularly relates to a wear-resistant coating for metal plates of compressed garbage trucks and a preparation method thereof. Background Art

[0002] Municipal garbage trucks face extremely demanding physical and chemical challenges during daily operations, posing a significant threat to the durability of their vehicle's interior panels. Physically, the interior walls of the vehicle are constantly subjected to intense friction and impact from various types of waste during the collection, compression, transportation, and dumping processes. Chemically, leachate from the garbage poses a severe threat of chemical and electrochemical corrosion to the vehicle's metal substrate and protective coatings. This complex wear environment places extremely high demands on the wear resistance, toughness, and corrosion resistance of the vehicle's interior lining or coating.

[0003] In this harsh environment, highly effective wear-resistant and anti-corrosion coatings are crucial for protecting the structural integrity and extending the service life of garbage truck body panels. These coating systems achieve dual protection by forming a tough, continuous protective barrier on the metal surface. On the one hand, they effectively isolate corrosive leachates, moisture, oxygen, and other substances from direct contact with the metal substrate, inhibiting electrochemical corrosion reactions and preventing rust and material degradation. On the other hand, their excellent wear resistance protects against the scratches, impacts, and abrasive wear caused by solid waste loading, unloading, and transportation, mitigating physical damage to the body panels. Through this comprehensive protection, the coating helps maintain the load-bearing capacity, sealing, and overall safety of the vehicle structure, avoiding environmental pollution and safety hazards caused by premature thinning or perforation of the panels. This significantly reduces maintenance frequency, lowers operating costs, and improves vehicle availability.

[0004] Despite the continuous advancement of wear-resistant and corrosion-resistant coating technology, existing coatings still face several key technical challenges in the actual application of garbage trucks. In the actual operating environment of garbage trucks, wear and corrosion do not exist in isolation, but rather reinforce each other, forming a complex synergistic destructive effect. This poses a severe challenge to the durability of protective coatings that far exceeds the impact of a single factor. Furthermore, mechanical damage and chemical corrosion to the coating can lead to premature failure, significantly reducing its adhesion and protective performance.

[0005] Currently, the existing coatings used for garbage truck metal plates are difficult to maintain good protective performance under corrosion and wear, which remains a major problem facing the industry.

[0006] To this end, a wear-resistant coating for a metal plate of a compressed garbage truck and a preparation method thereof are proposed. Summary of the Invention

[0007] The present invention aims to provide a wear-resistant coating for metal plates in compressed garbage trucks and a preparation method thereof. The method comprises pre-reacting and grafting bisphenol A epoxy resin with an amino-terminated polyether to obtain an epoxy prepolymer; mixing α-alumina and barium sulfate, dispersing and grinding, and surface-activating the mixture to obtain a base filler; adding a mica filler to the base filler and shear-mixing the mixture to obtain a composite filler; mixing the epoxy prepolymer with a phosphate ester additive to obtain a primer; and dispersing and mixing the epoxy prepolymer with a diluent, the composite filler, and a thixotropic agent to obtain a functional coating. After sandblasting the metal substrate, the primer is pre-sprayed on the metal substrate surface. After the primer dries, the functional coating is sprayed over the metal substrate surface and cured to obtain the wear-resistant coating.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck comprises the following steps:

[0010] Unless otherwise specified, the parts in the present invention refer to parts by mass.

[0011] Bisphenol A epoxy resin and amino-terminated polyether are pre-reacted and grafted to obtain epoxy prepolymer.

[0012] Among them, the bisphenol A epoxy resin is E-51 epoxy resin, with an epoxy equivalent of 0.45-0.5 mol / 100 g and a viscosity of 2.0 Pa·S (at 40°C); the amino-terminated polyether is polyoxypropylene diamine, CAS: 9046-10-0, with a total amide value of 4.1-4.7 meq / g and a viscosity of 22 mPa·S (at 25°C).

[0013] Alpha-alumina and barium sulfate were mixed in a mass ratio of 72:11-15 and then dispersed and ground at a grinding speed of 1200 rpm for 2 hours to obtain a dispersed filler.

[0014] The particle size of α-alumina is in the range of 20-40 μm, and the particle size of barium sulfate is in the range of 5-15 μm.

[0015] The dispersed filler is surface activated to obtain the basic filler.

[0016] Mica filler is added to the basic filler, and the composite filler is obtained after shear mixing.

[0017] The mica filler uses sericite powder with a specification of 400 mesh, a flake diameter distribution of 30-50 μm, and a diameter-to-thickness ratio of 30-50:1.

[0018] The epoxy prepolymer and the phosphate ester additive are mixed to obtain a primer.

[0019] The phosphate ester additives include: bis(2-ethylhexyl) phosphate and tris(2-chloroethyl) phosphate, and the addition mass ratio of bis(2-ethylhexyl) phosphate and tris(2-chloroethyl) phosphate is 1:3; the addition amount ratio of epoxy prepolymer and phosphate ester additive is 95:0.5-1.5.

[0020] The epoxy prepolymer is dispersed and mixed with a diluent, a composite filler and a thixotropic agent to obtain a functional coating.

[0021] Among them, the diluent includes: 1,4-butanediol diglycidyl ether and hexanediol diglycidyl ether; the thixotropic agent is fumed silica, specifically hydrophobic fumed silica, with a tap density of 45-50g / L, a carbon content of 0.6-1.0, volatile matter at 105°C ≤0.7%, and loss on ignition ≤2.5%.

[0022] After the metal substrate is sandblasted, the primer is pre-sprayed on the surface of the metal substrate. After the primer is dry, the functional coating is sprayed on the surface, and the wear-resistant coating is obtained after curing.

[0023] Preferably, the pre-reaction grafting modification process is as follows: under nitrogen protection, 110 parts of bisphenol A epoxy resin are heated to 60-70°C, stirred at a speed of 200 rpm, 25-32 parts of amino-terminated polyether are added dropwise, the temperature is raised to 80°C, stirring is continued, and the reaction is kept warm for 2 hours to obtain an epoxy prepolymer.

[0024] Preferably, the surface activation process is as follows: after mixing 100 parts of dispersed filler with 10-15 parts of wetting and dispersing agent, stirring and mixing at 40-50°C for 2 hours, heating to 100°C and aging for 1 hour, and drying and grinding to obtain the basic filler; wherein the wetting and dispersing agent is an isopropanol solution of γ-aminopropyltriethoxysilane, and its mass concentration is 1.5wt%.

[0025] Preferably, the shear mixing process is: after mixing 80 parts of the base filler and 10-15 parts of mica filler, adding 5 parts of a modifying agent, mixing at a speed of 300-500 rpm for 30 minutes, and obtaining a composite filler after drying; wherein the modifying agent includes: γ-glycidyloxypropyltrimethoxysilane, sorbitan monooleate and isopropyl alcohol, and the added mass ratio of γ-glycidyloxypropyltrimethoxysilane, sorbitan monooleate and isopropyl alcohol is 1:1:98.

[0026] Preferably, the dispersion mixing process is: at 50° C., 95 parts of epoxy prepolymer, 14 parts of composite filler, 11 parts of 1,4-butanediol diglycidyl ether and 2-5 parts of hexanediol diglycidyl ether are stirred and mixed, and then 0.2-1.4 parts of fumed silica are added and mixed before covering spraying to obtain a functional coating.

[0027] Preferably, the sandblasting process is: sandblasting the surface of the metal substrate with white corundum until the surface roughness Rz value of the metal substrate reaches 40-70 μm, and then blowing with compressed air; the particle size of the white corundum is 80-100 mesh.

[0028] Preferably, the pre-spraying process is: 2 hours after the sandblasting is completed, the primer is high-pressure airless sprayed on the surface of the metal substrate at a spraying pressure of 15-18 MPa, a spraying distance of 30 cm, and a spraying speed of 30-50 cm / s.

[0029] Preferably, the covering spraying process is: after the primer film prepared in the pre-spraying process is dry, the functional coating is high-pressure airless sprayed on the surface of the primer film at a spraying pressure of 20-22 MPa, the spraying distance is 30 cm, and the spraying speed is 30-50 cm / s. After completion, it is cured at 25°C for 168 hours to obtain a wear-resistant coating.

[0030] A wear-resistant coating for metal plates of compressed garbage trucks is obtained by spraying a primer onto the surface of a sandblasted metal substrate, covering it with a sprayed functional coating after the primer dries and then curing it. The wear-resistant coating comprises: a primer and a functional coating; and the total dry film thickness of the wear-resistant coating is 477-535 μm.

[0031] In the present invention, Q235 carbon steel is used as the metal substrate.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. By using bisphenol A epoxy resin as the main component, introducing a specific proportion of amino-terminated polyether for pre-reaction grafting modification, and effectively combining it with a coupling agent-modified composite filler, the toughness and impact resistance of the matrix are effectively improved, as well as the interfacial bonding strength between the filler and the matrix. Furthermore, the effective combination of the filler and the coating matrix enables the filler to effectively disperse and transfer stress, synergistically improving the wear resistance and fatigue resistance of the coating, avoiding defects caused by filler agglomeration, and improving the overall density of the coating, thereby enhancing corrosion resistance.

[0034] 2. By selecting α-alumina of a specific particle size as the primary wear-resistant framework and combining it with high-hardness barium sulfate as a fine filler, which is then surface-activated and added to the coating matrix, a multi-layered organic-inorganic cross-linked network is successfully constructed within the coating, significantly enhancing the coating's adhesion strength and wear resistance. Furthermore, the various particle sizes of base fillers are fully dispersed within the coating matrix, reducing stress concentrations and areas of weakness. Surface activation of the composite filler effectively improves the compatibility of the filler with the coating matrix, reducing the resin layer's direct exposure to abrasive environments and significantly extending the coating's overall service life.

[0035] 3. By adding layered mica fillers and maintaining their layered structure through a shear mixing process, a small amount of thixotropic agent acts during the spraying process of the functional coating to form a wear-resistant coating, causing the mica fillers in the coating to tend to align in parallel directions. This forms a multi-layered, dense physical barrier within the coating, making it difficult for corrosive media to penetrate the metal substrate surface, giving the coating excellent corrosion resistance. At the same time, the presence of the layered fillers can effectively inhibit the formation of cracks in the coating when subjected to external forces. Crack propagation will be deflected, bifurcated, or terminated when encountering the layered fillers, thereby simultaneously improving the coating's wear resistance and impact resistance.

[0036] 4. Pre-treat the metal substrate using sandblasting and pre-spray primer. After the primer reaches surface dryness but before it is completely dry, the functional coating is sprayed over it, achieving a dual-effect system of chemical bonding and physical interpenetration. The rough surface formed by sandblasting provides a large physical interlocking area for the coating. At the same time, the phosphate ester component in the primer can form a phosphating complex layer with the iron element in the metal substrate, achieving chemical anchoring at the molecular level. Furthermore, when the primer is not completely dry, the functional coating is sprayed over it, forming a continuous chemically bonded transition layer between the primer and the functional coating. This significantly improves the adhesion between the functional coating and the metal substrate, ensuring that the wear-resistant coating can provide long-term corrosion and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The figure is a flow chart of the preparation process of the functional coating and primer in the present invention. DETAILED DESCRIPTION

[0038] The technical solutions of the present invention are described clearly and completely below through some embodiments and experimental examples. Obviously, the embodiments described are only some embodiments of the present invention, not all 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.

[0039] Reference Figure 1 As shown in the process flow chart, the present invention provides a wear-resistant coating for metal plates of compressed garbage trucks and a preparation method thereof. The technical solution is as follows:

[0040] Example 1

[0041] Under nitrogen protection, 110 parts of bisphenol A epoxy resin were heated to 60°C and stirred at 200 rpm. After 25 parts of amino-terminated polyether were added dropwise, the temperature was raised to 80°C and stirring was continued. The mixture was kept warm for 2 hours to obtain an epoxy prepolymer.

[0042] α-alumina and barium sulfate were mixed in a mass ratio of 72:11 and then dispersed and ground at a grinding speed of 1200 rpm for 2 hours to obtain a dispersed filler.

[0043] 100 parts of dispersed filler and 10 parts of wetting and dispersing agent were mixed, stirred and mixed at 40°C for 2 hours, heated to 100°C and aged for 1 hour, and dried and ground to obtain a basic filler; wherein the wetting and dispersing agent was an isopropanol solution of γ-aminopropyltriethoxysilane with a mass concentration of 1.5wt%.

[0044] After mixing 80 parts of the base filler and 10 parts of mica filler, 5 parts of a modifying agent were added, mixed at a speed of 300 rpm for 30 minutes, and dried to obtain a composite filler; wherein the modifying agent includes: γ-glycidyloxypropyltrimethoxysilane, sorbitan monooleate and isopropyl alcohol, and the addition mass ratio of γ-glycidyloxypropyltrimethoxysilane, sorbitan monooleate and isopropyl alcohol is 1:1:98.

[0045] At 50° C., 95 parts of epoxy prepolymer, 14 parts of composite filler, 11 parts of 1,4-butanediol diglycidyl ether and 2-5 parts of hexanediol diglycidyl ether were stirred and mixed, and 0.2 parts of fumed silica was added and mixed before covering spraying to obtain a functional coating.

[0046] An epoxy prepolymer and a phosphate ester additive are mixed to obtain a primer; the addition ratio of the epoxy prepolymer to the phosphate ester additive is 95:0.5, the phosphate ester additive includes: bis(2-ethylhexyl) phosphate and tri(2-chloroethyl) phosphate, and the addition mass ratio of bis(2-ethylhexyl) phosphate to tri(2-chloroethyl) phosphate is 1:3.

[0047] The surface of the metal substrate was sandblasted with white corundum until the surface roughness Rz value of the metal substrate reached 40 μm, and then purged with compressed air.

[0048] Two hours after the sandblasting treatment, the primer was applied to the surface of the metal substrate by high-pressure airless spraying at a spraying pressure of 15 MPa, a spraying distance of 30 cm, and a spraying speed of 30 cm / s.

[0049] After the primer film prepared in the pre-spraying process is surface-dried, the functional coating is high-pressure airless sprayed on the surface of the primer film at a spraying pressure of 20 MPa, a spraying distance of 30 cm, and a spraying speed of 30 cm / s. After completion, the wear-resistant coating is obtained by curing at 25°C for 168 hours.

[0050] In Example 1, the total dry film thickness of the wear-resistant coating prepared was 514 μm.

[0051] Examples 2-16 differ from Example 1 in operating parameters, but are identical in process steps. The changes in operating parameters are summarized in Tables 1-3.

[0052] Table 1 Operation parameter changes of Examples 1-16 (I)

[0053]

[0054]

[0055] Table 2 Operation parameter changes of Examples 1-16 (II)

[0056]

[0057]

[0058] Table 3 Operation parameter changes of Examples 1-16 (III)

[0059]

[0060] Comparative Example 1

[0061] Unlike Example 1, the pre-reaction grafting modification of bisphenol A epoxy resin and amino-terminated polyether was not performed. The bisphenol A epoxy resin and amino-terminated polyether were directly mixed with other components to prepare the coating, and the other process parameters were the same.

[0062] Comparative Example 2

[0063] The difference from Example 1 is that the addition amount of the amino-terminated polyether is adjusted to 50 parts, and the other process parameters are the same.

[0064] Comparative Example 3

[0065] The difference from Example 1 is that the dispersed filler is not subjected to surface activation treatment, and no modifying agent is added when the basic filler and the mica filler are mixed. Other process parameters are the same.

[0066] Comparative Example 4

[0067] The difference from Example 5 is that no barium sulfate fine filler is added to the dispersed filler, and only α-alumina is used as the filler. Other process parameters are the same.

[0068] Comparative Example 5

[0069] The difference from Example 5 is that α-alumina with a particle size of 80-100 μm is used instead of the original α-alumina with a particle size of 20-40 μm, and the other process parameters are the same.

[0070] Comparative Example 6

[0071] The difference from Example 9 is that mica filler is not added during the preparation of the composite filler, and other process parameters are the same.

[0072] Comparative Example 7

[0073] The difference from Example 9 is that no fumed silica is added when preparing the functional coating, and other process parameters are the same.

[0074] Comparative Example 8

[0075] Different from Example 13, the metal substrate is not sandblasted, and the primer and functional coating are directly sprayed on the untreated metal surface. Other process parameters are the same.

[0076] Comparative Example 9

[0077] The difference from Example 13 is that after the primer is pre-sprayed, the functional coating is sprayed after the primer is completely cured, instead of spraying immediately after the primer is dry. The other process parameters are the same.

[0078] Comparative Example 10

[0079] The difference from Example 13 is that no primer is sprayed, and the functional coating is directly sprayed on the surface of the metal substrate after sandblasting. The other process parameters are the same.

[0080] Experimental Example 1

[0081] The wear resistance and corrosion resistance of the wear-resistant coatings prepared in Examples 1-4 and Comparative Examples 1-3 were tested, and the relevant results are summarized in Table 4.

[0082] The wear resistance test method is: use CS-17 grinding wheel to test the wear of the coating sample surface, and the friction area of ​​​​a single circle is 27.93cm 2 , the load is 1000g, and the coating mass loss (mg) after 1000 revolutions is recorded. The smaller the mass loss, the stronger the wear resistance of the coating.

[0083] The corrosion resistance test method is as follows: a straight scratch is made on the surface of the coating sample deep into the metal substrate. After continuous spraying with a 5wt% sodium chloride aqueous solution at 35°C for 1000 hours, the maximum single-side width (mm) of corrosion propagation on both sides of the scratch is measured according to the relevant provisions of the ASTM D1654 standard, and the degree of substrate rust in the non-scratched area is evaluated according to the ASTM D610 standard (10 = no rust, 0 = complete rust).

[0084] Table 4 Wear resistance and corrosion resistance of wear-resistant coatings prepared in Examples 1-4 and Comparative Examples 1-3

[0085]

[0086] As shown in the data of Table 4, Examples 1-4 are significantly better than Comparative Examples 1, 2 and 3 in terms of wear resistance and corrosion resistance. Comparative Example 1 did not undergo pre-reaction grafting modification, but directly mixed bisphenol A epoxy resin with a specific proportion of amino-terminated polyether. The results showed that the coating mass loss of Comparative Example 1 was much higher than that of Example 1, the corrosion spread width was also larger, and the degree of substrate rust was more serious. This shows that pre-reaction grafting modification is crucial to improving coating performance. Through pre-reaction, the flexible chain segments of the amino-terminated polyether are introduced into the rigid skeleton of the epoxy resin, effectively improving the toughness and impact resistance of the matrix. Comparative Example 2 added an excessive amount of amino-terminated polyether, resulting in an excessively high degree of cross-linking of the epoxy resin, which is not conducive to the subsequent effective combination with other additives and components, and reduces the wear resistance and corrosion resistance of the wear-resistant coating. In comparative example 3, the dispersed filler is not subjected to surface activation treatment, and the basic filler is not added with the mica filler when the modification aid is mixed. The wear resistance and corrosion resistance of the coating prepared therefrom are the worst, which fully demonstrates the key role of the coupling agent modification for enhancing the interfacial bonding force between the filler and the matrix. The coupling agent can bridge the inorganic filler and the organic epoxy matrix, significantly improving the compatibility and interfacial bonding strength of the two. This strong interfacial bonding enables stress to be effectively transferred from the matrix to the filler and dispersed, avoiding the defects caused by stress concentration and filler agglomeration, thereby synergistically promoting the wear resistance and fatigue resistance of the coating, and improving the compactness of the coating due to the reduction of interfacial defects, enhancing corrosion resistance.

[0087] In summary, the present invention optimizes the toughness and impact resistance of the epoxy matrix by pre-reacting and grafting bisphenol A epoxy resin with a specific ratio of amino-terminated polyether; at the same time, by surface-modifying the composite filler with a coupling agent, the interfacial bonding force between the filler and the modified epoxy matrix is ​​significantly enhanced. The synergistic effect of these two key technical means enables the filler to be more evenly dispersed in the matrix and effectively transfer and disperse stress, avoiding defects such as filler agglomeration and improving the overall density of the coating. Ultimately, these synergistic effects jointly contribute to a significant improvement in the wear resistance, fatigue resistance, and corrosion resistance of the coating.

[0088] Experimental Example 2

[0089] The wear-resistant coatings prepared in Examples 5-8 and Comparative Examples 4-5 were tested for wear resistance, adhesion strength, and aging resistance. The relevant results are summarized in Table 5.

[0090] The test method of wear resistance refers to Experimental Example 1.

[0091] The test method for adhesion strength is: refer to the method in the ASTM D3359 standard and evaluate according to the grade of 0B-5B. Grade 5B means that the scratch edge is completely smooth and there is no peeling, which has the highest adhesion strength. Grade 0B means that the coating peels off more than 65%, which is the worst grade.

[0092] The aging resistance test method involves immersing the coating sample in simulated landfill leachate at 25°C for 48 hours. The sample is then abraded using a CS-17 abrasive wheel at a load of 500g for 1000 revolutions, with one cycle being considered. The coating adhesion strength is recorded before the aging test, after 10 cycles, and after 50 cycles.

[0093] The composition of the simulated landfill leachate is: acetic acid 3.0 g / L, propionic acid 1.0 g / L, butyric acid 0.2 g / L, sodium chloride 4.2 g / L, ammonium sulfate 3.1 g / L, potassium dihydrogen phosphate 0.8 g / L, and the pH value is adjusted to 4-5.

[0094] Table 5 Wear resistance, adhesion strength and aging resistance of wear-resistant coatings prepared in Examples 5-8 and Comparative Examples 4-5

[0095]

[0096] As shown in the data in Table 5, Examples 5-8 are significantly superior to Comparative Examples 4 and 5 in terms of wear resistance, adhesion strength, and aging resistance. Comparative Example 4 does not add fine barium sulfate filler to the dispersed filler, and only uses α-alumina. Its coating mass loss is higher than that of Example 5, and the adhesion strength drops to 2B after 50 aging cycles, which is much lower than the 4B of Example 5. This shows that the introduction of fine barium sulfate filler forms a good gradation with α-alumina. The high-hardness barium sulfate fills the gaps in the α-alumina skeleton, forming a denser and multi-layered filler structure, effectively reducing defects and weak areas within the coating, thereby improving wear resistance and adhesion durability. Comparative Example 5 uses larger-particle α-alumina, and its coating mass loss is the highest among the three. Its adhesion strength after 50 aging cycles is also inferior to that of Example 5. This shows that the specific smaller-particle α-alumina can be more evenly dispersed in the matrix, forming a finer wear-resistant skeleton network, thereby providing better wear resistance and interface bonding. Fillers with too large particle size can lead to stress concentration and interface defects, affecting the final quality of the coating.

[0097] In summary, the present invention forms an optimized multi-level filler system by using α-alumina of a specific particle size as the main wear-resistant skeleton and compounding high-hardness barium sulfate as a fine filler. Combined with the surface activation treatment of the α-alumina filler, the interfacial bonding force and compatibility between the filler and the epoxy matrix are greatly enhanced. The synergistic effect of the specific particle size combination and surface activation enables the formation of a stable and dense organic-inorganic cross-linked network within the coating, effectively reducing stress concentration and weak performance areas, thereby significantly improving the adhesion strength and wear resistance of the coating, and giving it excellent anti-aging properties, extending the overall service life of the coating.

[0098] Experimental Example 3

[0099] The wear-resistant coatings prepared in Examples 9-12 and Comparative Examples 6-7 were tested for wear resistance, impact resistance, and corrosion resistance. The relevant results are summarized in Table 6.

[0100] The test method of wear resistance refers to Experimental Example 1.

[0101] The corrosion resistance test method is different from that of Experimental Example 1. Specifically, the coating sample is immersed in simulated landfill leachate at 40°C without setting scratches. The wear resistance data of the sample before the corrosion test and after immersion for 7 days are recorded, and the wear mass magnification (%) is calculated. The higher the magnification, the weaker the corrosion resistance of the coating sample to the simulated landfill leachate.

[0102] The impact resistance test method is as follows: refer to the relevant method of ASTM D2794, set the metal substrate thickness to 1mm, use a 12.7mm diameter hemispherical punch to directly impact the coating surface, and record the maximum impact energy (J) that the coating can withstand without damage.

[0103] Table 6 Wear resistance, impact resistance and corrosion resistance of wear-resistant coatings prepared in Examples 9-12 and Comparative Examples 6-7

[0104]

[0105] As shown in Table 6, Examples 9-12 significantly outperformed Comparative Examples 6 and 7 in terms of wear resistance, corrosion resistance, and impact resistance. Comparative Example 6 differs from Example 9 in that no mica filler was added during the preparation of the composite filler. The results show that the coating mass loss in Comparative Example 6 was much higher than that in Example 9, with poor corrosion resistance and significantly reduced impact resistance. This demonstrates that the introduction of layered mica fillers significantly improves the wear, corrosion, and impact resistance of the coating. The mica flaky structure in the coating extends the penetration path of corrosive media, thereby improving corrosion resistance. Furthermore, these flaky structures effectively deflect or terminate crack propagation, absorbing impact energy and thus improving impact and wear resistance. Comparative Example 7 differs from Example 9 in that no fumed silica was added during the preparation of the functional coating. The coating mass loss, wear mass magnification, and maximum impact energy were significantly inferior to those of Example 9, but slightly better than those of Comparative Example 6, which did not include any mica filler. This demonstrates that fumed silica, as a thixotropic agent, can modulate the coating's rheological properties. During high-shear spraying, it imparts shear-thinning properties, encouraging the mica flakes to align parallel to the substrate surface during flow and film formation. Once the shear force subsides, the thixotropic agent helps the coating quickly regain viscosity and stabilize the mica's orientation. This parallel layered structure maximizes both the physical barrier effect and crack deflection.

[0106] In summary, the present invention introduces a mica filler with a specific layered structure into the composite filler, combines it with a shear mixing process to maintain its layered structure, and adds fumed silica as a thixotropic agent to the functional coating. The synergistic effect of these three factors enables the mica filler to effectively align in parallel directions within the coating, thereby forming a multi-layered, dense physical barrier within the coating, significantly hindering the penetration of corrosive media and imparting excellent corrosion resistance to the coating. Furthermore, this layered structure effectively inhibits and deflects crack propagation, absorbs and disperses impact energy, and significantly improves the coating's wear resistance and impact resistance.

[0107] Experimental Example 4

[0108] The wear-resistant coatings prepared in Examples 13-16 and Comparative Examples 8-10 were tested for aging resistance and wear resistance. The relevant results are summarized in Table 7.

[0109] The test method for wear resistance refers to Experimental Example 1, and the test method for aging resistance refers to Experimental Example 2.

[0110] Table 7 Aging resistance and wear resistance of wear-resistant coatings prepared in Examples 13-16 and Comparative Examples 8-10

[0111]

[0112] As shown in the data of Table 7, Examples 13-16 are significantly better than Comparative Examples 8 and 9 in terms of adhesion strength, especially adhesion strength after aging cycles, while the gap in initial wear resistance is very small. The main difference between Comparative Example 8 and Example 13 is that the metal substrate is not sandblasted and is directly sprayed on the untreated surface. The results show that the initial adhesion strength of Comparative Example 8 is lower than that of Example 13, and the adhesion strength drops sharply to 1B after aging 50 times, which is much worse than 4B of Example 13. This shows that sandblasting forms a uniform rough morphology on the surface of the metal substrate, providing a huge physical interlocking area for subsequent coatings, which is a prerequisite for achieving good physical adhesion. At the same time, the phosphate ester additive added in the primer can react chemically with the iron element in the metal substrate to form a phosphating complex layer. This phosphating layer plays the role of a chemical bond bridge between the metal surface and the coating, achieving chemical anchoring at the molecular level. Comparative Example 9 differs from Example 13 in that, after pre-spraying the primer, the functional coating was sprayed on after the primer was fully cured. The initial adhesion strength was also lower than that of Example 13, and the adhesion strength after 50 aging cycles was significantly worse than that of Example 13, but slightly better than that of Comparative Example 8, which was not sandblasted. This indicates that even when the primer is dry but not completely dry, its surface still has a certain degree of reactivity and solvent wetting ability. When the functional coating is sprayed on, the resin and solvent in the functional coating can undergo a certain degree of mutual dissolution, penetration, and chemical cross-linking reaction with the primer surface. This forms a continuous, chemically bonded transition layer between the primer and the functional coating, rather than a simple physical superposition. This enhanced interlayer bonding further enhances the overall adhesion of the entire coating system to the metal substrate, particularly its ability to resist aging and environmental corrosion. Conversely, if the primer is allowed to fully cure, the primer surface activity decreases, relying primarily on physical adsorption to bond with the functional coating, resulting in weaker interlayer bonding. In Comparative Example 10, since no primer was sprayed, the bonding force between the functional coating layer and the metal substrate was significantly reduced, resulting in the coating adhesion before and after the aging experiment being significantly lower than that of Example 13.

[0113] In summary, the present invention creates an excellent physical anchoring foundation by sandblasting the metal substrate; combines this with a phosphate-containing primer to form a chemical anchor on the substrate surface; and utilizes a construction process in which the functional coating is sprayed on after the primer has dried, fostering the formation of a continuous, chemically bonded transition layer between the primer and the functional coating. The close synergy of these three technical approaches achieves a multi-faceted effect of physical intercalation, chemical anchoring, and interlayer chemical bonding, significantly improving the adhesion strength and durability of the entire wear-resistant coating system to the metal substrate, enabling it to provide long-lasting corrosion and wear resistance.

[0114] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck, characterized in that: The preparation method is as follows: Bisphenol A epoxy resin and amino-terminated polyether are pre-reacted and grafted to obtain epoxy prepolymer; α-alumina and barium sulfate are mixed and dispersed and ground to obtain a dispersed filler; Activating the surface of the dispersed filler to obtain a basic filler; Adding mica filler to the basic filler, and shearing and mixing to obtain a composite filler; mixing the epoxy prepolymer and the phosphate ester additive to obtain a primer; Dispersing and mixing the epoxy prepolymer and the diluent, the composite filler and the thixotropic agent to obtain a functional coating; After the metal substrate is sandblasted, the primer is pre-sprayed on the surface of the metal substrate. After the primer is dry, the functional coating is sprayed on the surface, and the wear-resistant coating is obtained after curing.

2. The method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck according to claim 1, characterized in that: The pre-reaction grafting modification process is as follows: under nitrogen protection, 110 parts by mass of the bisphenol A epoxy resin are heated to 60-70° C., stirred, 25-32 parts of the amino-terminated polyether are added dropwise, the temperature is raised to 80° C., stirring and reacting is continued, and the temperature is kept warm to obtain the epoxy prepolymer.

3. The method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck according to claim 1, characterized in that: The added mass ratio of the α-alumina and the barium sulfate is 72:11-15; the surface activation process is: after mixing 100 parts of the dispersed filler with 10-15 parts of the wetting and dispersing agent, stirring and mixing at 40-50° C., heating to 100° C. for aging, and drying and grinding to obtain the basic filler; wherein the wetting and dispersing agent is an isopropanol solution of γ-aminopropyltriethoxysilane with a mass concentration of 1.5wt%.

4. The method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck according to claim 1, characterized in that: The shear mixing process comprises: mixing 80 parts of the base filler and 10-15 parts of the mica filler, adding 5 parts of a modifying agent, mixing at a rotation speed of 300-500 rpm for 30 minutes, and drying to obtain the composite filler; wherein the modifying agent comprises: γ-glycidyloxypropyltrimethoxysilane, sorbitan monooleate, and isopropyl alcohol, and the addition mass ratio of the γ-glycidyloxypropyltrimethoxysilane, the sorbitan monooleate, and the isopropyl alcohol is 1:1:

98.

5. The method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck according to claim 1, characterized in that: The ratio of the added amount of the epoxy prepolymer and the phosphate ester auxiliary agent is 95:0.5-1.5; the phosphate ester auxiliary agent includes: bis(2-ethylhexyl) phosphate and tris(2-chloroethyl) phosphate, and the added mass ratio of the bis(2-ethylhexyl) phosphate and the tris(2-chloroethyl) phosphate is 1:

3.

6. The method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck according to claim 1, characterized in that: The diluent includes: 1,4-butanediol diglycidyl ether and hexanediol diglycidyl ether; the thixotropic agent is fumed silica; the dispersion and mixing process is: based on parts by mass, at 50° C., 95 parts of the epoxy prepolymer, 14 parts of the composite filler, 11 parts of the 1,4-butanediol diglycidyl ether and 2-5 parts of the hexanediol diglycidyl ether are stirred and mixed, and then 0.2-1.4 parts of the fumed silica are added and mixed before the covering spraying to obtain the functional coating.

7. The method for preparing a wear-resistant coating for a metal plate of a compressed garbage truck according to claim 1, characterized in that: The sandblasting process comprises: sandblasting the surface of the metal substrate with white corundum until the surface roughness Rz value of the metal substrate reaches 40-70 μm, and then blowing with compressed air; The pre-spraying process is as follows: 2 hours after completing the sandblasting, the primer is high-pressure airless sprayed on the surface of the metal substrate at a spraying pressure of 15-18 MPa, the spraying distance is 30 cm, and the spraying speed is 30-50 cm / s; the covering spraying process is as follows: after the primer film prepared in the pre-spraying process is surface-dried, the functional coating is high-pressure airless sprayed on the surface of the primer film at a spraying pressure of 20-22 MPa, the spraying distance is 30 cm, and the spraying speed is 30-50 cm / s. After completion, the coating is cured at 25°C for 168 hours to obtain the wear-resistant coating.

8. A wear-resistant coating for metal plates of compressed garbage trucks, characterized by: The wear-resistant coating for the metal plate of the compressed garbage truck is prepared by the preparation method according to any one of claims 1 to 7; the wear-resistant coating comprises: a primer and a functional coating.

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