Wear-resistant alkyd resin coating and preparation method thereof

Abstract

The invention discloses a wear-resistant alkyd resin coating and a preparation method thereof, and belongs to the technical field of alkyd resin paints.The preparation method comprises the steps that mixed vegetable oil is subjected to epoxidation and ring-opening-esterification modification to obtain modified mixed vegetable oil, then the modified mixed vegetable oil is subjected to esterification polycondensation and hydrophilic modification to obtain modified waterborne alkyd resin, meanwhile, phosphate betaine is used as a modifier, and the modified waterborne alkyd resin is prepared. Preparing modified nano cerium oxide through an in-situ precipitation method; and finally, mixing the modified waterborne alkyd resin, the modified nano cerium oxide and an auxiliary agent to obtain the wear-resistant alkyd resin coating. Through the cooperation of the epoxidized vegetable oil, the anhydride ring-opening cross-linked network and the in-situ modified nano cerium oxide, the defects that a traditional alkyd resin coating is insufficient in wear resistance, rigidity and toughness are difficult to balance and filler is easy to agglomerate are overcome, and the coating is endowed with excellent wear resistance, high hardness and good adhesive force and flexibility; and high-standard wear-resistant protection requirements of mechanical equipment, steel structures and the like are met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of alkyd resin paint, and particularly relates to a wear-resistant alkyd resin paint and a preparation method thereof. BACKGROUND

[0002] Alkyd resin is an important polyester resin prepared by polycondensation of polyols, polyacids and fatty acids or vegetable oils. Since the 20th century, alkyd resin has become one of the synthetic resins with the largest output and the widest application in the coating industry due to its wide raw material sources, mature synthesis process, low cost, high film fullness, strong adhesion and excellent construction performance, and is widely used in the protection and decoration of fields such as bridges, building steel structures, engineering machinery, ships and wooden furniture. With the increasingly stringent environmental regulations and the increasing demand for low volatile organic compounds (VOC) coatings, traditional solvent-based alkyd resin is gradually developing towards water-based direction. Water-based alkyd resin has become one of the current research and application hotspots due to its comprehensive performance and low VOC emission.

[0003] However, traditional alkyd resin paint has some inherent defects, which seriously limits its application in high-end or harsh environments. First, the three-dimensional network structure formed after the film is dried has limited crosslinking density, resulting in relatively low film hardness, insufficient wear resistance and scratch resistance. In daily use, the painted surface is easy to lose luster and produce scratches due to friction and scratching, affecting the appearance and shortening the protection period. In the industrial field (such as machine tool guide rails, factory floors, transportation tools, etc.), poor wear resistance may cause the coating to fail quickly and lose its protective effect on the substrate.

[0004] Chinese patent application with publication number CN109651781A discloses a wear-resistant water-based baking paint and a manufacturing method thereof. By increasing the crosslinking degree of the resin system and compounding glass fibers, metal powders and inorganic pigments and fillers as reinforcing phases in the water-based alkyd resin, a coating film structure with high mechanical strength is formed, thereby improving the wear resistance and scratch resistance of the coating.

[0005] However, the way to improve wear resistance by increasing crosslinking density or introducing high-rigidity structures often sacrifices the flexibility of the coating film, which easily causes the coating to become brittle and crack or peel off under conditions of temperature change or substrate deformation, making it difficult to balance wear resistance and use reliability. SUMMARY

[0006] The present application aims to provide a wear-resistant alkyd resin paint and a preparation method thereof, which solves the defects of insufficient wear resistance, difficult balance of rigidity and toughness, and easy aggregation of fillers of traditional alkyd resin paint by synergistic effect of epoxidized vegetable oil, anhydride ring-opening crosslinking network and in-situ modified nano cerium oxide, and endows the coating with excellent wear resistance, high hardness, good adhesion and flexibility, thereby meeting the high-standard wear-resistant protection requirements of mechanical equipment and steel structure.

[0007] The object of the present application can be achieved by the following technical solutions:

[0008] A preparation method of a wear-resistant alkyd resin paint, characterized in that it comprises the following steps:

[0009] Step one: mixed vegetable oil and hydrogen peroxide undergo epoxidation reaction under the catalysis of formic acid, and then the product is purified by extraction, and then the purified product is reacted with methyl tetrahydrophthalic anhydride to obtain modified mixed vegetable oil.

[0010] Step two: the modified mixed vegetable oil, cashew nut shell oil, polyol and polyacid are esterified and polycondensed, and then the product is hydrophilically modified by trimellitic anhydride to prepare a modified waterborne alkyd resin.

[0011] Step three: the cerium nitrate is modified by in-situ precipitation method using phosphate betaine as a modifier to obtain modified nano cerium oxide powder.

[0012] Step four: the modified waterborne alkyd resin, modified nano cerium oxide powder, talcum powder, wetting dispersant, defoaming agent, film-forming aid, leveling agent and deionized water are put into a stirring device, and then stepwise dispersion, mixing and filtration are performed to obtain the wear-resistant alkyd resin paint.

[0013] Further, the mass ratio of the modified waterborne alkyd resin, modified nano cerium oxide powder, talcum powder, wetting dispersant, defoaming agent, film-forming aid, leveling agent and deionized water is 40-60:15-20:3-5:0.3-0.6:0.1-0.2:5-8:0.4-0.6:30-40.

[0014] Further, the specific preparation steps of the modified waterborne alkyd resin are as follows:

[0015] The modified mixed vegetable oil, cashew shell oil, diethylene glycol, benzoic acid, terephthalic acid, phthalic anhydride, pentaerythritol and xylene are sequentially added to the reaction kettle, and reacted at 250-350 r / min and 208-212℃ for 5-6h, 70-80℃, add trimellitic anhydride, 40-60r / min stirring dispersion 10-12min, continue to react at 250-350r / min and 158-162℃ for 2.5-3h, until the product acid value <40mg KOH / g, stop heating and cooling to 143-147℃, vacuum removal of xylene, continue to cool to 50℃, add ethylene glycol monobutyl ether and distilled water, fully stirred and mixed uniformly, then filtered through a 200 mesh filter screen to obtain a modified water-based alkyd resin.

[0016] Further, the mass ratio of the modified mixed vegetable oil, cashew shell oil, diethylene glycol, benzoic acid, terephthalic acid, phthalic anhydride, pentaerythritol, xylene, trimellitic anhydride, ethylene glycol monobutyl ether and distilled water is 100:10.7-28.6:10.7-28.6:46.3-64.3:7.1-21.4:1.8-5.4:42.9-60.7:17.9-28.6:2-7:21.4-42:55-70.

[0017] Further, the specific preparation steps of the modified mixed vegetable oil are as follows:

[0018] Nitrogen is passed throughout the process, the epoxidized mixed vegetable oil, methyl tetrahydrophthalic anhydride and 2,4,6-tris(dimethylaminomethyl)phenol are added to the reaction kettle, stirred uniformly at 55-65℃ and 300-500r / min, then placed at 148-152℃ for 1.5-2.5h, the reaction endpoint is controlled by monitoring the product acid value and epoxy value, when the acid value ≤5mg KOH / g and the epoxy residue ≤0.05mol / 100g, the reaction is completed, to obtain the modified mixed vegetable oil.

[0019] Further, the mass ratio of the epoxidized mixed vegetable oil, methyl tetrahydrophthalic anhydride and 2,4,6-tris(dimethylaminomethyl)phenol is 100-140:20-30:0.2-0.3.

[0020] Further, the specific preparation steps of the epoxidized mixed vegetable oil are as follows:

[0021] The plant oil mixture is added to the reaction kettle, formic acid is added at 550-650r / min, and a 30% mass fraction of hydrogen peroxide aqueous solution is slowly added to the kettle within 30-45min, after the addition is completed, the speed is maintained and the temperature is raised to 58-62℃ for continuous reaction for 7-9h, after the reaction is completed, it is cooled to room temperature, dichloromethane is added for extraction, washed, dried, impurities are removed, concentrated to obtain the epoxidized mixed vegetable oil.

[0022] Further, the mass ratio of the vegetable oil mixture, formic acid and aqueous hydrogen peroxide solution is 80-120:6.5-8.5:15-20.

[0023] Further, the vegetable oil mixture is a mixture of castor oil, soybean oil and tung oil in a mass ratio of 4:3:2.

[0024] Further, the specific preparation steps of the modified nano cerium oxide powder are as follows:

[0025] Deionized water and phospholipid betaine are added to a reaction kettle, stirred at 300-500 r / min until dissolved, then cerium nitrate hexahydrate is added and stirred uniformly, an 8.4wt% sodium hydroxide aqueous solution is slowly added dropwise at 65-75 DEG C and under continuous stirring within 30 min, after the dropwise addition is completed, the reaction is carried out for 1.5-2.5 h, after the reaction is completed, filtration, washing and drying are carried out to obtain the modified nano cerium oxide powder.

[0026] Further, the amount ratio of deionized water, phospholipid betaine, cerium nitrate hexahydrate and sodium hydroxide aqueous solution is 40-60 mL:0.5-1 g:14-16 g:40-60 mL.

[0027] The beneficial effects of the present application are:

[0028] 1. The present application solves the core defects that the traditional alkyd resin coating is prone to brittleness and cracking due to the sacrifice of flexibility caused by simply increasing the crosslinking density or introducing rigid structures by constructing an epoxy plant oil / acid anhydride modified active resin matrix, functionalized waterborne alkyd resin and in-situ modified nano cerium oxide ternary synergistic enhancement system.

[0029] 2. The present application realizes the synergistic design of rigidity and toughness of the resin matrix at the molecular level through the epoxy and acid anhydride ring-opening-esterification modification technology, the flexible double bond in the plant oil is converted into a high-activity epoxy group by epoxy, and a customizable reaction platform is constructed, and the rigid benzene ring structure is chemically bonded on the platform by acid anhydride ring-opening, which endows the coating with high hardness and excellent wear resistance, and through the microstructure of "rigid chain segment dispersed in flexible matrix", the silver line is induced under stress and the crack propagation is prevented, ensuring that the coating has good flexibility and impact resistance, breaking through the bottleneck that wear resistance and toughness are difficult to balance in traditional technology.

[0030] In addition, the modified resin is rich in polar groups such as carboxyl and ester groups, which significantly enhances the interfacial compatibility and force with fillers and substrates, further improving the overall mechanical properties of the composite material. The modified vegetable oil also has the characteristics of thermal phase change, being a solid reinforcing phase at room temperature and melting and flowing at high temperature, realizing good flowability during processing, and re-solidifying into a reinforcing network after cooling, thereby endowing the coating with certain temperature responsiveness and structural designability. The system maintains the environmental protection characteristics and good processing adaptability of bio-based materials while improving the performance, thereby providing a feasible path for the development of high-performance and environmentally friendly coatings.

[0031] 3. The present application prepares nanometer cerium oxide fillers with high surface activity and excellent interfacial compatibility through in-situ modification technology of phosphatidyl betaine. The technology enables the nanometer particles to be coated by amphiphilic molecules instantly after generation, the phosphatidyl groups are strongly anchored to the inorganic surface, and the betaine structure and long alkyl chain extend outward. This design completely solves the agglomeration problem of nanometer fillers in resin at the macro level, ensuring the storage stability of the coating. At the micro level, the modified nanometer particles can directly improve the wear resistance through physical blocking and bearing effect, the organic shell can further interact with the polar groups of the modified resin to form an "organic-inorganic" bridging network, effectively dispersing external force, thereby synergistically improving the overall mechanical strength, durability and adhesion to the substrate of the coating. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0033] Embodiment 1: A wear-resistant alkyd resin coating is prepared by the following method:

[0034] S1: 100 g of a mixture of vegetable oils (castor oil, soybean oil and tung oil in a mass ratio of 4:3:2) is added to a reaction kettle, 7.5 g of an oxidation catalyst formic acid is added at a rotation speed of 600 r / min, 17.5 g of a 30% mass fraction hydrogen peroxide aqueous solution is slowly added to the kettle within 30-45 min, after the addition is completed, the rotation speed is maintained and the temperature is increased to 60°C, and the reaction is continued for 8 h. After the reaction is completed, the reaction liquid is cooled to room temperature, dichloromethane is added for extraction. The organic phase is washed with water, saturated sodium bicarbonate solution and saturated sodium chloride solution in sequence, dried with anhydrous sodium sulfate, filtered to remove the drying agent, and the filtrate is concentrated under reduced pressure to obtain an epoxidized mixed vegetable oil.

[0035] Based on the epoxidation reaction of olefins, first, in the acidic environment of formic acid catalyst, hydrogen peroxide reacts with formic acid to generate peroxymonocarbonate in situ with high reactivity, which is the key oxygen carrier. The active oxygen atom in the molecule immediately attacks the carbon-carbon double bond (C=C) in the unsaturated fatty acid structural unit in the molecular chain of mixed vegetable oil (castor oil, soybean oil, tung oil), and this electrophilic addition process makes an oxygen atom inserted between the carbon-carbon double bond, thereby converting the unstable double bond into a stable three-membered oxygen heterocyclic structure, i.e. epoxy group (-C(O)C-), completing the epoxidation reaction. The product obtained is extracted, washed with alkali to neutralize the residual acid catalyst, washed with water and salted to purify, and then the epoxidized mixed vegetable oil is obtained.

[0036] S2: Nitrogen is passed throughout, 120g of epoxidized mixed vegetable oil, 24g of methyl tetrahydrophthalic anhydride and 0.24g of 2,4,6-tris(dimethylaminomethyl)phenol are added into the reaction kettle, stirred uniformly under the condition of temperature 60℃ and rotation speed 400r / min, then placed at 150℃ for 2h, the reaction endpoint is controlled by monitoring the product acid value and epoxy value, when the acid value ≤5mgKOH / g and the residual epoxy ≤0.05mol / 100g, it is considered that the reaction is completed, and the modified mixed vegetable oil is obtained.

[0037] Based on the acid anhydride ring-opening-esterification synergistic reaction, under the protection of nitrogen, 2,4,6-tris(dimethylaminomethyl)phenol catalyzes the nucleophilic ring-opening of methyl tetrahydrophthalic anhydride and the three-membered epoxy ring in the epoxidized mixed vegetable oil to generate a half-ester intermediate containing carboxyl-ester groups, then the system is heated to 150℃, the carboxylic acid in the half-ester structure is further esterified and dehydrated with the adjacent hydroxyl group to form a cross-linked network, and the excess acid anhydride ensures the complete conversion of epoxy, and the modified mixed vegetable oil with rigid ester ring and flexible fatty chain is obtained.

[0038] S3: 100 g of modified mixed vegetable oil, 19.7 g of cashew nut shell oil, 19.7 g of diethylene glycol, 55.3 g of benzoic acid, 14.3 g of terephthalic acid, 3.6 g of phthalic anhydride, 51.8 g of pentaerythritol and 23.3 g of refluxing solvent dimethylbenzene were sequentially added to a reaction kettle, and esterification reflux reaction was carried out at a rotation speed of 300 r / min and a temperature of 210°C for 5.5 h, water was removed through a water trap, and the acid value was monitored in real time until the acid value of the reaction product was <70 mg KOH / g, heating was stopped and the temperature was lowered to 75°C, 4.5 g of trimellitic anhydride was added to the kettle, and it was kept at a rotation speed of 50 r / min for 11 min to make it fully dispersed, and then reaction was continued at a rotation speed of 300 r / min and a temperature of 160°C for 3 h until the acid value of the product was <40 mg KOH / g, heating was stopped, the material was cooled to 145°C, and dimethylbenzene in the system was removed by vacuumizing, the temperature was continuously lowered to below 50°C, 31.7 g of ethylene glycol monobutyl ether and 62.5 g of distilled water were added, and after being fully stirred and mixed, the impurities were removed by filtering through a 200-mesh filter screen to obtain a modified water-based alkyd resin.

[0039] Based on the principles of step-by-step condensation and hydrophilic modification, first, the modified mixed vegetable oil (containing rigid ester ring), cashew nut shell oil, polyol (pentaerythritol, diethylene glycol) and polybasic acid (benzoic acid, terephthalic acid, phthalic anhydride) undergo esterification polycondensation at high temperature, and the balance is pushed by removing reaction water to form an alkyd resin prepolymer connected by ester bonds, with rigid ring structure and flexible fatty chain. The acid value meets the standard, indicating that the carboxyl group is fully consumed and the molecular chain growth is complete; then the system is cooled, trimellitic anhydride is added, the anhydride groups react with the residual hydroxyl groups of the prepolymer to form ring-opening esterification, which further increases the crosslinking density and introduces additional carboxyl groups as hydrophilic sites; finally, the solvent is removed, and water is dispersed under the action of film-forming additives (ethylene glycol monobutyl ether) to form a stable water dispersion of the carboxylated resin, and the final product is obtained after filtration.

[0040] S4: 50 mL of deionized water and 0.75 g of phosphate betaine (PB) were added to a reaction kettle, and stirred at a rotation speed of 400 r / min until completely dissolved, then 14.92 g of cerium nitrate hexahydrate was added, and the solution was continuously stirred until homogeneous. The system was heated to 70°C, and under continuous stirring at this temperature, 50 mL of 8.4 wt% sodium hydroxide aqueous solution was slowly added dropwise within 30 min. After the addition was completed, the reaction was continued at 70°C for 2 h. After the reaction was completed, the reaction mixture was filtered, and the precipitate was repeatedly washed with hot water at 90°C until the last filtrate was neutral. The obtained solid was vacuum dried at 60°C for 20 h to obtain modified nano cerium oxide powder.

[0041] S5: 50 g of the modified waterborne alkyd resin was added into a stirred tank, and the stirring was continued for 6.5 min at a temperature of 38℃ and a stirring speed of 400 r / min to reduce the viscosity of the resin and remove the air bubbles, then 0.45 g of wetting dispersant BYK-190, 0.08 g of defoaming agent BYK-024, 4 g of talc (1250 mesh) and 17.5 g of the modified nano cerium oxide powder were sequentially added into the tank, the stirring speed was increased to 1000 r / min and the stirring was continued for 18 min to fully pre-disperse the nano filler, then the system was cooled to 26℃, and 6.5 g of film-forming aid dipropylene glycol methyl ether, 0.5 g of leveling agent BYK-333 and 0.08 g of defoaming agent BYK-024 were sequentially added into the system at a stirring speed of 450 r / min, and the stirring was continued for 12 min until the mixture was uniformly mixed, finally 35 g of deionized water was added to adjust the viscosity, and the stirring was continued for 8 min at a stirring speed of 350 r / min, then the impurities were removed by filtering through a 200 mesh filter screen, and a wear-resistant alkyd resin coating was obtained.

[0042] Examples 2-3: A wear-resistant alkyd resin coating, which is different from Example 1 in that the addition amount of the substances in step S1 is different, and the remaining steps and parameters remain unchanged, and the specific addition amount is shown in Table 1.

[0043] Table 1: Comparison table of the addition amount of substances in step S1

[0044] Group Vegetable oil mixture (g) Formic acid (g) Aqueous hydrogen peroxide solution (g) Example 2 80 6.5 15 Example 3 120 8.5 20

[0045] Examples 4-5: A wear-resistant alkyd resin coating, which is different from Example 1 in that the addition amount of the substances in step S2 is different, and the remaining steps and parameters remain unchanged, and the specific addition amount is shown in Table 2.

[0046] Table 2: Comparison table of the addition amount of substances related to step S2

[0047] Group Epoxidized mixed vegetable oil (g) Methyltetrahydrophthalic anhydride (g) 2,4,6-tris(dimethylaminomethyl)phenol (g) Example 4 100 20 0.2 Example 5 140 30 0.3

[0048] Examples 6-7: A wear-resistant alkyd resin coating and a preparation method thereof, which is different from Example 1 in that the addition amount of the substances in step S3 is different, and the remaining steps and parameters remain unchanged, and the specific addition amount is shown in Table 3.

[0049] Table 3: Comparison table of the addition amount of substances in step S3

[0050] Group Modified mixed vegetable oil (g) Cashew nut shell liquid (g) Diethylene glycol (g) Benzoic acid (g) Terephthalic acid (g) Phthalic anhydride (g) Pentaerythritol (g) Xylene (g) Trimellitic anhydride (g) Ethylene glycol monobutyl ether (g) Distilled water (g) Example 6 100 10.7 10.7 46.3 7.1 1.8 42.9 17.9 2 21.4 55 Example 7 100 28.6 28.6 64.3 21.4 5.4 60.7 28.6 7 42 70

[0051] Example 8: A wear-resistant alkyd resin coating, which is different from Example 1 in that the ratio of the addition amount of deionized water, phosphinate betaine, cerium nitrate hexahydrate and sodium hydroxide aqueous solution in step S4 is 60 mL: 1 g: 16 g: 60 mL, and the remaining steps and parameters remain unchanged.

[0052] The raw materials used in the embodiments 1-8 of the present application are all commercially available, among which, castor oil, soybean oil, tung oil, formic acid, pentaerythritol are purchased from Shanghai Aldrin Biochemical Co., Ltd.; hydrogen peroxide (analytical pure) is purchased from Chongqing Wansheng Chuandong Chemical Co., Ltd.; methyl tetrahydrophthalic anhydride and 2,4,6-tris(dimethylaminomethyl) phenol (DMP-30) are industrial grade purchased from Shanghai Resin Factory Co., Ltd.; cashew nut shell liquid (99%) is purchased from P&G (Shanghai) International Trade Co., Ltd.; diethylene glycol (99%), benzoic acid (≥99%), terephthalic acid (99%), phthalic anhydride (99.7%) and xylene (99%) are purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.; pentaerythritol is purchased from Hubei Yihua Chemical Co., Ltd.; trimellitic anhydride is purchased from Jinjinle Chemical Co., Ltd.; ethylene glycol monobutyl ether is purchased from Dow Chemical; wetting dispersant BYK-190 and leveling agent BYK-333 are purchased from Guangzhou Yinman New Material Co., Ltd.; defoamer BYK-024 is purchased from Guangdong Wengjiang Chemical Reagent Co., Ltd.; talc powder (1250 mesh) is purchased from Xi'an Jinxing Pharmaceutical Auxiliary Material Co., Ltd.; dipropylene glycol methyl ether (purity 98%) is purchased from Shanghai Pu Zhen Biological Technology Co., Ltd.

[0053] The betaine phosphate is prepared according to the reference [1] Yan Xuhua, Tang Lanqin. Synthesis and performance of betaine phosphate modified ZnO [J]. China Surfactants, 2025, 55(11): 1402-1407.

[0054] Comparative Example 1: On the basis of Example 1, steps S1 and S2 are omitted, and the raw material modified mixed vegetable oil in step S3 is replaced with original vegetable oil mixture (castor oil, soybean oil and tung oil, mass ratio 5:3:2) without any modification, and all other steps and parameters remain the same as Example 1, to obtain an alkyd resin paint.

[0055] Comparative Example 2: On the basis of Example 1, 100g of castor oil is used to replace 100g of the mixture of vegetable oils in step S1, and only it is used as the raw material for the subsequent reaction, and the raw material addition amount and process parameters remain the same as Example 1, to obtain an alkyd resin paint.

[0056] Comparative Example 3: On the basis of Example 1, in the paint preparation stage of step S4, the same amount of ordinary nano cerium oxide powder without betaine phosphate (PB) treatment is used as the filler instead of the modified nano cerium oxide powder in Example 1, except for the change of the filler, all other steps, raw material addition amount and process parameters remain the same as Example 1, to obtain an alkyd resin paint.

[0057] The alcohol acid resin paint prepared in Example 1-Example 8 and Comparative Example 1-Comparative Example 3 was film-formed: by one-time coating, the dry film thickness was controlled to be 45±5 μm, the coated test panel was placed horizontally under standard test conditions of temperature 23±2℃ and relative humidity 50±5% and leveled for 10 min, and then placed in a constant temperature and humidity chamber for 7 d to allow it to fully cure, to obtain a coating film sample for testing.

[0058] Based on the coating film, subsequent performance tests were carried out, in which the abrasion resistance was determined according to the method specified in the standard GB / T 1768-2006, a rotary abrasion tester was used, a standard rubber grinding wheel was used with a load of 1000 g to rotate and rub the surface of the coating film sample for 500 r, the mass loss (mg) of the paint film was determined by a precision balance, the lower the value, the stronger the anti-friction loss ability of the coating, and the better the abrasion resistance.

[0059] The hardness was determined according to the method specified in the standard GB / T 6739-2006, a standard drawing pencil with known hardness (6B to 9H) was used, the coating film was scratched at an angle of 45°, and the highest hardness pencil grade of the unscratched coating film was taken as the pencil hardness of the coating, the higher the hardness grade, the stronger the rigidity of the coating surface.

[0060] The adhesion was determined according to the method specified in the standard GB / T 9286-2021, a multifunctional grid marker was used to prepare a grid scratch with a spacing of 1 mm on the surface of the paint film to the substrate, after cleaning, a special pressure-sensitive adhesive tape was pasted and quickly peeled off, and the degree of coating film peeling from the grid was evaluated according to the standard atlas (0-5 grade), in which 0 grade indicates that the cutting edge is completely smooth and no grid is peeled off, the lower the grade, the stronger the adhesion of the coating.

[0061] The flexibility was determined according to the method specified in the standard GB / T 1731-2020, the paint surface of the coating film test panel was placed upward, and the coating film was bent at 180° at a uniform speed within 1 s on a shaft rod with a specified diameter (1 mm-32 mm), and a 4-fold magnifying lens was used to observe whether the coating film at the bending part produced a mesh pattern, cracks or peeling, the minimum shaft rod diameter (mm) that did not cause damage to the coating film was used to evaluate the flexibility, the smaller the diameter, the better the flexibility of the coating film.

[0062] The impact resistance test was determined according to the method specified in the standard GB / T 1732-2020, a fixed height impact tester was used, a weight with a specified mass of 1 kg was allowed to fall freely, and the coating film on the back of the test panel was impacted, the falling height of the weight was gradually increased (5 cm per step), and the coating film at the impact site was checked for cracks, wrinkles or peeling, the product of the maximum impact height and the weight mass (kg·cm) that did not cause damage to the coating film was used to represent the impact resistance, the higher the value, the stronger the anti-instantaneous impact ability of the coating.

[0063] The test results are shown in Table 4.

[0064] Table 4 Performance test results of each alkyd resin paint

[0065]

[0066] As can be seen from Table 4, by using the synergistic effect of the epoxy-modified mixed vegetable oil / anhydride modified resin and the synergistic film-forming system and the phosphate betaine (PB) surface-modified nano ceria functional enhancement system, the synergistic and breakthrough improvement of the alkyd resin paint in high wear resistance, excellent adhesion, good flexibility and high impact resistance and other key mechanical properties is realized.

[0067] The wear resistance and impact resistance of the sample in Comparative Example 1 are the lowest among all groups, and the pencil hardness, adhesion and flexibility are all substandard. This result may be because it completely uses the traditional alkyd resin process, and omits the core epoxy-modified vegetable oil-anhydride ring-opening modification of the present application. On the one hand, the rigid benzene ring structure introduced by the ring-opening reaction of methyl tetrahydrophthalic anhydride is missing as a molecular skeleton crosslinking point, resulting in a lack of sufficient hardness and rigid support for the resin network, which macroscopically manifests as insufficient hardness and easy wear. On the other hand, the modified vegetable oil molecular chain has excessive flexibility, and the interface compatibility with inorganic fillers is poor, resulting in stress concentration and accelerated crack propagation, which manifests as a significant decrease in impact resistance and flexibility. This result from the opposite side confirms that the construction of a rigid-flexible molecular structure is the fundamental prerequisite for achieving a high wear resistance and high toughness balance of the coating, highlighting the cornerstone role of the resin chemical modification step of the present application.

[0068] The performance results of Comparative Example 2 are not good. Only castor oil is used as raw material, and the mixed system of castor oil-soybean oil-tung oil in the present application is missing. Although castor oil contains hydroxyl groups which are beneficial for reaction, its single structure cannot provide the high rigid benzene ring unit contributed by tung oil and the chain segment flexibility contributed by soybean oil, which leads to a lack of sufficient rigid points to resist deformation and wear in the prepared resin matrix, and it is difficult to optimize between hardness and toughness due to the lack of diversified chain segment synergy. At the same time, the single source of fatty acid composition may reduce the broad spectrum compatibility with nano fillers and substrates, which manifests as a serious decrease in adhesion. This result proves that the specific functional combination of the mixed vegetable oil is a key design variable for regulating the comprehensive performance of the resin, rather than a simple replacement of raw materials.

[0069] The performance of Comparative Example 3 is better than that of Comparative Examples 1 and 2, but still significantly worse than all the examples, the core defect of which is that the in-situ surface modification process of phosphobetaine in step S4 is omitted, and the common nano cerium oxide is directly used, the surface energy of the CeO2 nanoparticles without PB modification is extremely high, and serious agglomeration will occur in the hydrophobic resin matrix, these agglomerates become stress concentration points and structural weak points in the coating, not only cannot play the role of dispersion strengthening and scratch resistance of nanoparticles, but also will induce and accelerate the initiation and propagation of cracks, resulting in the wear resistance cannot reach the expected improvement, at the same time, the agglomeration also damages the interface bonding between the filler and the resin, affecting the overall rigidity, this result shows that the phosphobetaine surface treatment process is the key step to play the function of nano cerium oxide and realize the nano enhancement effect.

[0070] It should be noted that in this text, such as the term "include", "contain" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or includes elements inherent to such process, method, article or device.

[0071] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the present application.

Claims

1. A process for the preparation of a wear resistant alkyd resin coating characterized in that, Preparation by the following steps: Step one: mixed vegetable oil and hydrogen peroxide in the presence of formic acid catalysis epoxidation reaction, purification by extraction, and then reacted with methyl tetrahydrophthalic anhydride to obtain modified mixed vegetable oil; Step two: modified mixed vegetable oil, cashew nut shell oil, polyol and polyacid esterification polycondensation, and then modified by trimellitic anhydride to prepare modified water-based alkyd resin; Step three: with phosphate betaine as modifier, cerium nitrate is modified by in-situ precipitation method to obtain modified nano cerium oxide powder; Step four: the modified water-based alkyd resin, modified nano cerium oxide powder, talc, wetting dispersant, defoaming agent, film forming aid, leveling agent and deionized water are put into stirring equipment, and then dispersed, mixed and filtered step by step to obtain wear-resistant alkyd resin paint.

2. A process for the preparation of a wear resistant alkyd resin paint as claimed in claim 1, wherein, The mass ratio of the modified water-based alkyd resin, modified nano cerium oxide powder, talc, wetting dispersant, defoaming agent, film forming aid, leveling agent and deionized water is 40-60:15-20:3-5:0.3-0.6:0.1-0.2:5-8:0.4-0.6:30-40.

3. A process for the preparation of a wear resistant alkyd resin paint as claimed in claim 1, wherein, The specific preparation steps of the modified water-based alkyd resin are as follows: The modified mixed vegetable oil, cashew nut shell oil, diethylene glycol, benzoic acid, terephthalic acid, phthalic anhydride, pentaerythritol and dimethylbenzene are sequentially added into a reaction kettle, and then stirred and dispersed at 250-350 r / min and 208-212℃ for 5-6 h; trimellitic anhydride is added at 70-80℃, and then stirred and dispersed at 40-60 r / min for 10-12 min; then the reaction is carried out at 250-350 r / min and 158-162℃ for 2.5-3 h; vacuum is applied at 143-147℃ to remove dimethylbenzene; the temperature is lowered to 50℃, and then ethylene glycol monobutyl ether and distilled water are added; after fully stirring and mixing, impurities are removed by filtration to obtain the modified water-based alkyd resin.

4. A process for the preparation of a wear resistant alkyd resin paint as claimed in claim 3, wherein, The mass ratio of the modified mixed vegetable oil, cashew nut shell oil, diethylene glycol, benzoic acid, terephthalic acid, phthalic anhydride, pentaerythritol, dimethylbenzene, trimellitic anhydride, ethylene glycol monobutyl ether and distilled water is 100:10.7-28.6:10.7-28.6:46.3-64.3:7.1-21.4:1.8-5.4:42.9-60.7:17.9-28.6:2-7:21.4-42:55-70.

5. A process for the preparation of a wear resistant alkyd resin paint as claimed in claim 3, wherein, The specific preparation steps of the modified mixed vegetable oil are as follows: Nitrogen is introduced throughout the process, and the epoxidized mixed vegetable oil, methyl tetrahydrophthalic anhydride and 2,4,6-tris(dimethylaminomethyl)phenol are added into a reaction kettle; after being stirred and mixed at 55-65℃ and 300-500 r / min, the reaction is carried out at 148-152℃ for 1.5-2.5 h to obtain the modified mixed vegetable oil.

6. A process for the preparation of a wear resistant alkyd resin paint as claimed in claim 5, wherein, The mass ratio of the epoxidized mixed vegetable oil, methyl tetrahydrophthalic anhydride and 2,4,6-tris(dimethylaminomethyl)phenol is 100-140:20-30:0.2-0.

3.

7. A process for the preparation of a wear resistant alkyd resin paint as claimed in claim 5, wherein, The specific preparation steps of the epoxidized mixed vegetable oil are as follows: The plant oil mixture is added into a reaction kettle, formic acid is added at 550-650 r / min, 30wt% hydrogen peroxide aqueous solution is slowly added into the kettle in 30-45 min, after the dropping is completed, the rotation speed is kept and the temperature is raised to 58-62℃ to continue the reaction for 7-9 h, after the reaction is completed, the temperature is cooled to room temperature, dichloromethane is added to extract, after washing, drying, impurity removal, concentration, a mixed plant oil epoxidation product is obtained; The mass ratio of the plant oil mixture, formic acid and hydrogen peroxide aqueous solution is 80-120:6.5-8.5:15-20.

8. A process for the preparation of a wear resistant alkyd resin coating as claimed in claim 7, wherein, The plant oil mixture is a mixture of castor oil, soybean oil and tung oil with a mass ratio of 4:3:

2.

9. The method of preparing a wear resistant alkyd resin paint according to claim 1, characterized in that, The specific preparation steps of the modified nano cerium oxide powder are as follows: Deionized water and phosphinate betaine are added into a reaction kettle, stirred at 300-500 r / min until dissolved, then cerium nitrate hexahydrate is added and stirred uniformly, 8.4wt% sodium hydroxide aqueous solution is added dropwise in 30 min at 65-75℃ and continuous stirring, after the dropping is completed, the reaction is carried out for 1.5-2.5 h, after the reaction is completed, the modified nano cerium oxide powder is obtained after filtration, washing and drying; The dosage ratio of the deionized water, phosphinate betaine, cerium nitrate hexahydrate and sodium hydroxide aqueous solution is 40-60 mL:0.5-1 g:14-16 g:40-60 mL.

10. A wear resistant alkyd resin coating, characterized in that, The modified nano cerium oxide powder is prepared by the preparation method of any one of claims 1-9.

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