Fluorine-containing coating for super-weather-resistant winding adhesive tape and preparation method of fluorine-containing coating

Abstract

The invention relates to the technical field of fluorine-containing coatings, in particular to a fluorine-containing coating for a super-weather-resistant winding adhesive tape and a preparation method of the fluorine-containing coating, and the fluorine-containing coating is prepared from the following components in parts by mass: 45-55 parts of hyperbranched perfluoropolyether glycol, 12-13 parts of tetraethoxysilane, 30-40 parts of hexamethylene diisocyanate tripolymer and the like. By designing the synergistic effect of a gradient-distributed fluorocarbon skeleton and an organic-inorganic hybrid network and combining surface-modified nano reinforced particles, the coating constructs a directional protective barrier on the molecular level, the interface stability is remarkably improved through a multi-stage bonding mechanism, the body durability is enhanced by utilizing the synergistic effect of a nanophase and a matrix, and the coating has a good application prospect. The weather resistance of the product in an extreme environment is doubled, the flexibility and the surface self-cleaning function are both considered, and the product has a wide application prospect in the field of winding protection under harsh working conditions such as ocean engineering and energy pipelines.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorine-containing coating, in particular to a fluorine-containing coating for super-weather-resistant wrapping tape and a preparation method thereof. BACKGROUND

[0002] As a corrosion-proof sealing material for major infrastructures such as oil pipelines and offshore wind power facilities, wrapping tape is subjected to ultraviolet radiation, salt spray corrosion and mechanical stress cycles for a long time. The long-term stability of the surface coating in extreme environments becomes a core indicator of the protection life. Fluorine-containing coatings are considered an ideal choice for achieving super-weather resistance due to their excellent ultraviolet aging resistance and chemical inertness resulting from the high bond energy of C-F bonds.

[0003] In the prior art, although the coating based on linear polyvinylidene fluoride or fluorine-olefin copolymer has basic weather resistance, the uniform distribution of fluorine elements leads to insufficient surface energy regulation, which cannot effectively block acid rain penetration. In addition, the modulus mismatch between the rigid fluorocarbon chain and the flexible tape substrate easily causes interfacial peeling under dynamic winding stress. Moreover, the unmodified nanoparticles introduced to enhance hardness have poor compatibility with fluororesin, which leads to stress concentration points caused by the aggregation of the dispersed phase and accelerates the expansion of micro-cracks under ultraviolet aging.

[0004] Therefore, according to the related technology in the above, it is urgent to develop a fluorine-containing coating for super-weather-resistant wrapping tape and a preparation method thereof. SUMMARY

[0005] Therefore, the present application aims to provide a fluorine-containing coating for super-weather-resistant wrapping tape and a preparation method thereof to solve the problems of insufficient hydrophobicity of fluorine-containing coatings, peeling caused by rigid-flexible interface mismatch, and defects in nano-dispersion stability in the prior art.

[0006] To achieve the above purpose, the present application provides a fluorine-containing coating for super-weather-resistant wrapping tape and a preparation method thereof.

[0007] A fluorine-containing coating for super-weather-resistant wrapping tape is composed of the following components by mass: hyperbranched perfluoropolyether diol 45-55 parts, tetraethyl orthosilicate 12-13 parts, hexamethylene diisocyanate trimer 30-40 parts, modified nano-silicon dioxide 4-6 parts, catalyst dibutyltin dilaurate 0.5-1 part, and leveling agent BYK-381 0.4-0.6 part. The modified nano-silicon dioxide is perfluorooctyltriethoxysilane modified nano-silicon dioxide.

[0008] Preferably, the preparation steps of the hyperbranched perfluoropolyether diol are as follows: Step A1: under nitrogen atmosphere, the perfluoropolyether diol was added into tetrahydrofuran solution, stirred to dissolve, heated to 50-70℃, glycidyl methacrylate and triethylamine were added, reacted for 5-7h, the reaction was completed, cooled to 20-30℃, distilled under reduced pressure, to obtain the epoxy-terminated perfluoropolyether diol; Step A2: under nitrogen atmosphere, the epoxy-terminated perfluoropolyether diol was added into tetrahydrofuran solution, stirred to dissolve, hydroxyethyl acrylate and initiator azobisisobutyronitrile were added, heated to 60-80℃, reacted for 7-9h, the reaction was completed, to obtain the reaction liquid; Step A3: the reaction liquid was added into deionized water, stirred to mix, catalyst triethylamine was added, heated to 90-110℃, refluxed for 3-5h, the reaction was completed, cooled to 20-30℃, separated, washed, dried, distilled under reduced pressure, to obtain the hyperbranched perfluoropolyether diol; The hyperbranched perfluoropolyether diol was constructed by epoxy-acrylate cascade reaction to form a three-dimensional network, and the terminal perfluoroalkyl chains migrated to the surface of the coating during curing, and simultaneously condensed with the silicon hydroxyl generated by hydrolysis of tetraethyl orthosilicate to form covalent bonds, so that the fluorine chains were stably anchored at the inorganic-organic interface.

[0009] Preferably, the mass ratio of the perfluoropolyether diol, glycidyl methacrylate and triethylamine in step A1 is 1:0.2-0.24:0.014-0.016.

[0010] Preferably, the mass ratio of the epoxy-terminated perfluoropolyether diol, hydroxyethyl acrylate and initiator in step A2 is 1:0.48-0.52:0.008-0.012.

[0011] Preferably, the mass ratio of the reaction liquid and catalyst in step A3 is 1:0.004-0.006.

[0012] Preferably, the preparation steps of the modified nanosilica are as follows: Step B1: under nitrogen atmosphere, the perfluorooctyltriethoxysilane was added into anhydrous ethanol, deionized water was added, heated to 20-30℃, and hydrolyzed for 20-40min to obtain the hydrolysis liquid; Step B2: the nanosilica was added into anhydrous ethanol, ultrasonically treated for 20-40min at a power of 400-600W, the hydrolysis liquid was added, heated to 50-70℃, stirred to react for 7-9h at a speed of 500-700rpm, acetic acid was added to adjust the pH to 5-6, the reaction was completed, washed by centrifugation, and vacuum dried to obtain the modified silica; The nano-silica is modified by perfluoroalkyl silane, the surface of the nano-silica is grafted with perfluoroalkyl long chains, the nano-particles are embedded in a hybrid network, the hardness is improved, the compatibility with hyperbranched perfluoropolyether diol segments is optimized, agglomeration is avoided, the surface fluorine chains form a super-low surface energy layer with the hyperbranched perfluoropolyether diol, and the hydrophobicity is increased; Preferably, the mass ratio of the perfluoroalkyl silane to the deionized water in step B1 is 1:0.15-0.17.

[0013] Preferably, the mass ratio of the nano-silica, the anhydrous ethanol and the hydrolyzate in step B2 is 1:15.6-16:8-8.4.

[0014] A preparation method of the fluorine-containing coating for the super-weather-resistant wrapping tape, and the preparation steps are as follows: Step S1: tetraethyl orthosilicate and 0.1 mol / L hydrochloric acid aqueous solution are added into propylene glycol methyl ether acetate solvent, the temperature is raised to 50-70 DEG C, reaction is carried out for 1.5-2.5 h, the rotation speed is 400-600 rpm, and a transparent sol is obtained; Step S2: hyperbranched perfluoropolyether diol and the transparent sol are added into propylene glycol methyl ether acetate solvent, the temperature is raised to 70-90 DEG C, stirring reaction is carried out for 2-4 h, the rotation speed is 300-500 rpm, reaction is completed, and a prepolymer is obtained; Step S3: modified nano-silica is added into the prepolymer, the temperature is raised to 30-40 DEG C, ultrasonic treatment is carried out for 20-40 min, the power is 400-600 W, the mixture is placed in a high-speed homogenizer, reaction is carried out for 50-70 min, the rotation speed is 1800-2200 rpm, a leveling agent is added, stirring is carried out for 10-20 min, the rotation speed is reduced to 150-250 rpm, hexamethylene diisocyanate trimer and a catalyst dibutyltin dilaurate are added, stirring is carried out for 10-20 min, the rotation speed is raised to 700-900 rpm, and the fluorine-containing coating is obtained; The tetraethyl orthosilicate is hydrolyzed into silica sol under acid catalysis, and the hydroxyl groups of the hyperbranched perfluoropolyether diol are condensed to form Si-O-C / F interpenetrating networks, the inorganic Si-O bond resists ultraviolet degradation, and the organic fluorine chain blocks chemical corrosion media.

[0015] Preferably, the mass ratio of the tetraethyl orthosilicate to the hydrochloric acid aqueous solution in step S1 is 1:0.07-0.09; The mass ratio of the hyperbranched perfluoropolyether diol to the transparent sol in step S2 is 1.7-1.8:1; The mass ratio of the modified nano-silica, the prepolymer, the leveling agent, the hexamethylene diisocyanate trimer and the catalyst in step S3 is 0.028-0.032:1:0.0028-0.0032:0.21-0.23:0.004-0.006.

[0016] The present application has the following beneficial effects: The application provides a fluorine-containing paint for super-weather-resistant wrapping adhesive tape, and realizes an innovative breakthrough in material structure by designing gradient distribution of a fluorocarbon skeleton and organic-inorganic hybrid network synergistic effect, and combining with surface-modified nano-enhanced particles. Compared with the prior art, the paint constructs a directional protective barrier at a molecular level, significantly improves interface stability through a multi-stage bonding mechanism, and enhances the body durability by using the synergistic effect of a nano phase and a matrix, so that the weather resistance of the product is doubled in an extreme environment, while flexibility and surface self-cleaning function are considered, and the product has a wide application prospect in the field of wrapping protection in harsh working conditions such as marine engineering and energy pipeline. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the application clearer, the application is further described in detail below with specific examples.

[0018] Example 1: The preparation steps of the hyperbranched perfluoropolyether diol are as follows: S1: Under a nitrogen atmosphere, 100g of perfluoropolyether diol is added to 200mL of tetrahydrofuran solution, stirred and dissolved, heated to 50℃, 20g of glycidyl methacrylate and 1.4g of triethylamine are added, reacted for 7h, the reaction is completed, cooled to 20℃, and distilled under reduced pressure to obtain epoxy-terminated perfluoropolyether diol; S2: Under a nitrogen atmosphere, 100g of epoxy-terminated perfluoropolyether diol is added to 200mL of tetrahydrofuran solvent, stirred and dissolved, 48g of hydroxyethyl acrylate and 0.8g of initiator azobisisobutyronitrile are added, heated to 60℃, reacted for 9h, the reaction is completed, and a reaction liquid is obtained; S3: 100g of the reaction liquid is added to 100mL of deionized water, stirred and mixed, 0.4g of catalyst triethylamine is added, heated to 90℃, refluxed for 5h, the reaction is completed, cooled to 20℃, separated and washed, dried, and distilled under reduced pressure to obtain hyperbranched perfluoropolyether diol.

[0019] Example 2: The preparation steps of the hyperbranched perfluoropolyether diol are as follows: S1: Under a nitrogen atmosphere, 100g of perfluoropolyether diol is added to 200mL of tetrahydrofuran solution, stirred and dissolved, heated to 60℃, 22g of glycidyl methacrylate and 1.5g of triethylamine are added, reacted for 6h, the reaction is completed, cooled to 25℃, and distilled under reduced pressure to obtain epoxy-terminated perfluoropolyether diol; S2: Under a nitrogen atmosphere, 100g of epoxy-terminated perfluoropolyether diol is added to 200mL of tetrahydrofuran solvent, stirred and dissolved, 48g of hydroxyethyl acrylate and 0.8g of initiator azobisisobutyronitrile are added, heated to 60℃, reacted for 6h, the reaction is completed, and a reaction liquid is obtained; S3: 100 g of the reaction solution was added to 100 mL of deionized water, mixed by stirring, 0.5 g of catalyst triethylamine was added, the temperature was raised to 100°C, and refluxed for 4 h. After the reaction was completed, the temperature was lowered to 25°C, the layers were separated and washed, dried, and distilled under reduced pressure to obtain hyperbranched perfluoropolyether diol.

[0020] Example 3: The preparation steps of hyperbranched perfluoropolyether diol are as follows: S1: 100 g of perfluoropolyether diol was added to 200 mL of tetrahydrofuran solution under a nitrogen atmosphere, stirred and dissolved, the temperature was raised to 70°C, 24 g of glycidyl methacrylate and 1.6 g of triethylamine were added, and the reaction was carried out for 5 h. After the reaction was completed, the temperature was lowered to 30°C, and distilled under reduced pressure to obtain epoxy-terminated perfluoropolyether diol; S2: 100 g of epoxy-terminated perfluoropolyether diol was added to 200 mL of tetrahydrofuran solvent under a nitrogen atmosphere, stirred and dissolved, 52 g of hydroxyethyl acrylate and 1.2 g of initiator azobisisobutyronitrile were added, the temperature was raised to 80°C, and the reaction was carried out for 7 h. After the reaction was completed, the reaction solution was obtained; S3: 100 g of the reaction solution was added to 100 mL of deionized water, mixed by stirring, 0.6 g of catalyst triethylamine was added, the temperature was raised to 110°C, and refluxed for 3 h. After the reaction was completed, the temperature was lowered to 30°C, the layers were separated and washed, dried, and distilled under reduced pressure to obtain hyperbranched perfluoropolyether diol.

[0021] Example 4: The preparation steps of modified nano-silica are as follows: S1: 100 g of perfluorooctyl triethoxysilane was added to 200 mL of anhydrous ethanol under a nitrogen atmosphere, 15 g of deionized water was added, the temperature was raised to 20°C, and the hydrolysis was carried out for 40 min to obtain a hydrolysis solution; S2: 10 g of nano-silica was added to 156 g of anhydrous ethanol, ultrasonic treatment was carried out for 20 min at a power of 600 W, 80 g of the hydrolysis solution was added, the temperature was raised to 50°C, and the reaction was carried out for 9 h under stirring at a speed of 500 rpm. Acetic acid was added to adjust the pH to 5-6. After the reaction was completed, centrifugal washing and vacuum drying were carried out to obtain modified silica.

[0022] Example 5: The preparation steps of modified nano-silica are as follows: S1: 100 g of perfluorooctyl triethoxysilane was added to 200 mL of anhydrous ethanol under a nitrogen atmosphere, 16 g of deionized water was added, the temperature was raised to 25°C, and the hydrolysis was carried out for 30 min to obtain a hydrolysis solution; S2: 10 g of nano-silica was added to 158 g of anhydrous ethanol, ultrasonic treatment for 30 min, power 500 W, 82 g of hydrolysis solution was added, heated to 60℃, stirring reaction for 8 h, rotation speed 600 rpm, acetic acid was added, pH was adjusted to 5-6, the reaction was completed, centrifugal washing, vacuum drying, modified silica was obtained.

[0023] Example 6: The preparation steps of modified nano-silica were as follows: S1: 100 g of perfluorooctyltriethoxysilane was added to 200 mL of anhydrous ethanol under nitrogen atmosphere, 17 g of deionized water was added, heated to 30℃, stirring hydrolysis for 20 min, hydrolysis solution was obtained; S2: 10 g of nano-silica was added to 160 g of anhydrous ethanol, ultrasonic treatment for 40 min, power 400 W, 84 g of hydrolysis solution was added, heated to 70℃, stirring reaction for 7 h, rotation speed 700 rpm, acetic acid was added, pH was adjusted to 5-6, the reaction was completed, centrifugal washing, vacuum drying, modified silica was obtained.

[0024] Example 7: A preparation method of fluorine-containing coating for super-weather-resistant wrapping tape: S1: 100 g of tetraethyl orthosilicate, 7 g of 0.1 mol / L hydrochloric acid aqueous solution was added to 200 mL of propylene glycol methyl ether acetate solvent, heated to 50℃, reaction for 2.5 h, rotation speed 400 rpm, transparent sol was obtained; S2: 170 g of hyperbranched perfluoropolyether diol (Example 1) and 100 g of transparent sol were added to 300 mL of propylene glycol methyl ether acetate solvent, heated to 70℃, stirring reaction for 4 h, rotation speed 300 rpm, the reaction was completed, pre-polymer was obtained; S3: 2.8 g of modified nano-silica (Example 4) was added to 100 g of pre-polymer, heated to 30℃, ultrasonic treatment for 40 min, power 400 W, placed in a high-speed homogenizer, reaction for 70 min, rotation speed 1800 rpm, 0.28 g of leveling agent was added, stirring for 20 min, rotation speed was reduced to 150 rpm, 21 g of hexamethylene diisocyanate trimer and 0.4 g of catalyst dibutyltin dilaurate were added, stirring for 20 min, rotation speed was increased to 700 rpm, fluorine-containing coating was obtained.

[0025] Example 8: A preparation method of fluorine-containing coating for super-weather-resistant wrapping tape: S1: 100 g of tetraethyl orthosilicate, 8 g of 0.1 mol / L hydrochloric acid aqueous solution was added to 200 mL of propylene glycol methyl ether acetate solvent, heated to 60℃, reaction for 2 h, rotation speed 500 rpm, transparent sol was obtained; S2: 175 g of hyperbranched perfluoropolyether diol (Example 2) and 100 g of transparent sol were added to 300 mL of propylene glycol methyl ether acetate solvent, heated to 80°C, stirred for 3 h at 400 rpm, and the reaction was completed to obtain a prepolymer; S3: 3 g of modified nanosilica (Example 5) was added to 100 g of the prepolymer, heated to 35°C, ultrasonically treated for 30 min at 500 W, placed in a high-speed homogenizer, reacted for 60 min at 2000 rpm, 0.3 g of a leveling agent was added, stirred for 15 min at 200 rpm, 22 g of hexamethylene diisocyanate trimer and 0.5 g of a catalyst dibutyltin dilaurate were added, stirred for 15 min, and the stirring speed was increased to 800 rpm to obtain a fluorine-containing coating.

[0026] Example 9: A preparation method of a fluorine-containing coating for a super-weather-resistant wrapping tape: S1: 100 g of tetraethyl orthosilicate and 9 g of 0.1 mol / L hydrochloric acid aqueous solution were added to 200 mL of propylene glycol methyl ether acetate solvent, heated to 70°C, reacted for 1.5 h at 600 rpm, and a transparent sol was obtained; S2: 180 g of hyperbranched perfluoropolyether diol (Example 3) and 100 g of transparent sol were added to 300 mL of propylene glycol methyl ether acetate solvent, heated to 90°C, stirred for 2 h at 500 rpm, and the reaction was completed to obtain a prepolymer; S3: 3.2 g of modified nanosilica (Example 6) was added to 100 g of the prepolymer, heated to 40°C, ultrasonically treated for 20 min at 600 W, placed in a high-speed homogenizer, reacted for 50 min at 2200 rpm, 0.32 g of a leveling agent was added, stirred for 10 min at 250 rpm, 23 g of hexamethylene diisocyanate trimer and 0.6 g of a catalyst dibutyltin dilaurate were added, stirred for 20 min, and the stirring speed was increased to 700 rpm to obtain a fluorine-containing coating.

[0027] Example 10: A preparation method of a fluorine-containing coating for a super-weather-resistant wrapping tape The fluorine-containing coating (Example 7) was scraped onto the tape substrate with a coater, the film thickness was 30 μm, and the fluorine-containing coating was obtained by placing it in an oven, heating to 70°C, baking for 12 min, heating to 130°C, and baking for 15 min.

[0028] Example 11: A preparation method of a fluorine-containing coating for a super-weather-resistant wrapping tape The fluorine-containing coating (Example 8) was scraped onto the tape substrate with a coater, the film thickness was 30 μm, and the fluorine-containing coating was obtained by placing it in an oven, heating to 80°C, baking for 10 min, heating to 120°C, and baking for 20 min.

[0029] Example 12: A method for preparing a fluorine-containing coating for super-weatherable wrapping tape The fluorine-containing coating (Example 9) was applied on the tape substrate by a coater with a film thickness of 30 μm, and was placed in an oven, and was heated to 90 °C for 8 min, and was heated to 110 °C for 25 min, to obtain the fluorine-containing coating.

[0030] Comparative Example 1: This comparative example is compared with Example 10, and the process of heating to 70 °C for 12 min, and heating to 130 °C for 15 min in the preparation of the fluorine-containing coating for super-weatherable wrapping tape is changed to heating to 120 °C for 30 min, and the other steps and parameters are the same, and this comparative example will not be repeated, and finally the fluorine-containing coating is obtained.

[0031] Comparative Example 2: This comparative example is compared with Example 10, and only the “hyperbranched perfluoropolyether diol” is replaced by “linear polyvinylidene fluoride”, and the other steps and parameters are the same, and this comparative example will not be repeated, and finally the fluorine-containing coating is obtained.

[0032] Comparative Example 3: This comparative example is compared with Example 10, and only the “modified nano-silicon dioxide” is replaced by “hydrophilic nano-silicon dioxide”, and the other steps and parameters are the same, and this comparative example will not be repeated, and finally the fluorine-containing coating is obtained.

[0033] Comparative Example 4: This comparative example is compared with Example 10, and only the “tetraethyl orthosilicate” is replaced by “epoxy silane coupling agent KH-560”, and the other steps and parameters are the same, and this comparative example will not be repeated, and finally the fluorine-containing coating is obtained.

[0034] Performance test: UV aging resistance test: According to the test standard of ISO 4892-3, a UV aging box, a 60° gloss meter and a spectrophotometer were used; 1. Respectively, 5.0 g of Example 10-12 and Comparative Example 1-4 were placed in a constant temperature box, the temperature was 23±2 °C, and the RH was 50±5%, and was cured for 168 h; 2. The sample was taken out and placed in a UV aging box, the wavelength was 340 nm, the irradiance was 0.76±0.02 W / m 2 , the light stage temperature was 60±3 °C, and lasted for 4 h, the condensation stage temperature was 50±3 °C, and lasted for 4 h, and the cycle was 240 h, and the sample was taken out and detected by a 60° gloss meter and a spectrophotometer respectively to detect the gloss loss rate and the color difference; 3. The gloss loss rate calculation formula is: G0: 60° gloss value of the sample before aging test, G1: 60° gloss value of the sample after aging test; 4. Color difference calculation formula: L1, a1, b1: measurement of the sample after aging, L0, a0, b0: measurement of the sample before aging.

[0035] Table 1 UV aging resistance test results Mechanical property test Abrasion resistance test According to GB / T 23988-2009 test standard, using sand falling abrasion tester; 1. Take the samples of Examples 10-12 and Comparative Examples 1-4, respectively, with a diameter of 25 mm, fixed at 45° below the sand flow impact point, with a drop distance of 1 m, a sand flow of 16.5±0.5 g, and a total mass of 2000 g of standard sand poured into the funnel, freely impacting the surface of the coating, and weighing the mass of the coating after impact M1; 2. Unit area mass loss calculation formula: A: wear area (cm 2 ).

[0036] Flexibility test According to GB / T 6742-2007 test standard, using a cone and shaft bending tester; 1. Take the samples of Examples 10-12 and Comparative Examples 1-4, respectively, cut into 150 mm x 50 mm, and bend the sample along the smallest axis diameter 2T by 180°, if there is no cracking, test 1T, if cracking, measure 3T, and only find the smallest T value without cracking; 2. Result judgment: 0T: directly folded (0° bending) without cracking, 1T: bending around 1 times thickness axis without cracking, 2T: bending around 2 times thickness axis without cracking, 1T is the optimal grade, proving excellent flexibility.

[0037] Adhesion test According to ISO 2409 grid method test standard, take the samples of Examples 10-12 and Comparative Examples 1-4, respectively, with a size of 100 mm x 100 mm, use a knife perpendicular to the sample surface, draw out 6 x 6 1 mm 2 squares, clean the debris, and tightly attach the adhesive tape to the grid area, then tear it off at a 60° angle after 60 s, observe the peeling condition, and grade it from 0 to 5, with 0-1 grade being qualified.

[0038] Table 2 Mechanical property test results of examples and comparative examples Hydrophobicity test Contact angle test Test liquid: ultrapure deionized water 1. Take the fluorine-containing coatings of Examples 7-9 and Comparative Examples 1-4, uniformly blade-coat on 50 mm x 50 mm butyl rubber substrates, gradiently cure and maintain for 168 h, clean the surface with anhydrous ethanol and nitrogen blowing before testing to avoid fingerprint pollution; 2. Drop 5 μL water droplets vertically on the sample surface with a microsyringe, the liquid droplets freely fall 5 mm from the surface, take the average value of the left and right contact angles, and θ > 150° is super-hydrophobic.

[0039] Rolling angle test Use an inclined platform instrument 1. Take the fluorine-containing coatings of Examples 7-9 and Comparative Examples 1-4, uniformly blade-coat on 50 mm x 50 mm butyl rubber substrates, gradiently cure and maintain for 168 h, clean the surface with anhydrous ethanol and nitrogen blowing before testing to avoid fingerprint pollution; 2. Fix the sample horizontally on the platform, drop 10 μL water droplets on the surface, and tilt the platform at a uniform speed of 1° / s, and record the tilting angle α when the water droplets first roll.

[0040] Table 3. Hydrophobic performance test results of examples and comparative examples “*” Note: Rolling angle > 90° indicates that the water droplets do not roll but spread directly, recorded as > 90*.

[0041] Chemical resistance: Refer to the test standard of ISO 9227-2017, use a cyclic salt spray chamber, 5.0 ± 0.5% NaCl solution 1. Take the samples of Examples 10-12 and Comparative Examples 1-4, respectively, with a size of 150 mm x 100 mm, use a 30° blade angle cutter to draw two intersecting lines on the coating surface, 50 mm long, deep to the substrate, with an angle of 60°, place the sample at an angle of 20 ± 5° to the vertical direction in the cyclic salt spray chamber, with a sedimentation amount of 1.5 mL, 80 cm / h, after taking out the sample, rinse with deionized water, and dry at room temperature for 24 h 2 ; 2. Calculation formula: W0: initial scratch width, W1: maximum corrosion expansion width after corrosion.

[0042] Acid resistance test Refer to the test standard of ISO 9227-2017, 10.0 ± 0.5% H2SO4 solution 1. Take 5.0 g of the samples of Examples 10-12 and Comparative Examples 1-4, respectively, dry the samples in an oven at 50℃ for 2 h, weigh m0 after cooling, immerse the samples in acid liquid, update the acid liquid every 24 h, take out the samples, rinse with deionized water, absorb surface moisture with filter paper, dry at 50℃ for 2 h, weigh m1 after cooling; 2. Calculation formula: Table 4 Test results of chemical resistance of examples and comparative examples Data analysis: As can be seen from Tables 1-4, the fluorine-containing coating prepared by the present application has more excellent ultraviolet aging resistance, mechanical properties, superhydrophobicity and chemical resistance for super-weatherable wrapping tape; Comparative Example 1, due to the deletion of "heat to 70℃, bake for 12 min, then heat to 130℃, bake for 15 min" in the preparation process of the fluorine-containing coating for super-weatherable wrapping tape and the replacement of "heat to 120℃ and bake for 30 min", the gloss loss and etching width increased significantly, the flexibility and adhesion decreased, and the hydrophobicity was poor. The reason is that the silicon hydroxyl generated by the hydrolysis of tetraethyl orthosilicate needs to be gradually condensed with the hydroxyl of the hyperbranched perfluoropolyether diol at low temperature to form Si-O-C covalent bond and build inorganic-organic interpenetrating network skeleton. The high temperature triggers the directional migration of perfluoroalkyl chains to the surface of the coating to form a dense fluorocarbon barrier. However, the constant temperature of 120℃ makes the condensation of silica sol too fast, and the migration of fluorine chains lags behind, resulting in incomplete bonding of the inorganic phase (Si-O) and the organic phase (C-F) interface, and enrichment of fluorine elements inside the coating, insufficient surface concentration, and poor hydrophobicity. In addition, the single temperature of 120℃ makes the high-polarity silica sol network form preferentially, physically blocking the migration path of fluorine chains, and the fluorine chains are "locked" inside the coating, unable to form a low surface energy layer. At the same time, the simultaneous rapid curing of the substrate and the coating at 120℃ causes shear stress concentration at the interface, and the difference in shrinkage after cooling causes microcracks. Comparative Example 2, due to the replacement of hyperbranched fluorine ether with linear polyvinylidene fluoride, the abrasion resistance and ultraviolet resistance are poor, the hydrophobicity is insufficient, and the flexibility is reduced. The reason is that linear polymers lack the three-dimensional network of hyperbranched structure, resulting in uneven distribution of fluorine elements, failure of surface energy regulation, mismatch of rigid chain segments and tape substrate modulus, easy peeling under dynamic stress, and stress concentration caused by poor dispersion of nanoparticles; Comparative Example 3, due to the replacement of modified nano-silicon dioxide with hydrophilic nano-silicon dioxide, the acid resistance and hydrophobicity are weaker than those of the examples, and the etching width increases. The reason is that the unmodified nanoparticles have poor compatibility with the fluororesin due to the presence of hydrophilic groups on the surface, leading to agglomeration. At the same time, the lack of the synergistic effect of perfluoroalkyl chains makes it impossible to form a super-low surface energy layer, and the acid liquid easily penetrates and erodes the interface. The reason is that tetraethyl orthosilicate is hydrolyzed to silica sol under acidic conditions and condenses with the hydroxyl groups of the hyperbranched fluorine ether to form a three-dimensional Si-O-C / F covalent network. As an epoxy silane coupling agent, the epoxy group of KH-560 preferentially undergoes ring-opening reaction with the hydroxyl groups of the fluorine ether, consumes the bonding sites, and the residual methoxyl group hydrolyzes to form isolated ≡Si-OH, which cannot be extended into a continuous inorganic network. The organic phase and the inorganic phase are only connected by flexible alkyl chains, and the rigid Si-O skeleton support is missing. In addition, the nano-reinforcement fails, and the overall compactness of the coating collapses.

[0043] Those skilled in the art should understand that the above discussion of any of the embodiments is only exemplary and is not intended to imply that the scope of the present application is limited to these examples; under the idea of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the present application as described above. In order to be brief, they are not provided in details.

[0044] The present application is intended to cover all such alternatives, modifications, and variations as fall within the broad scope of the appended claims. Accordingly, any and all such modifications, variations, and equivalents that fall within the spirit and scope of the present application are intended to be included.

Claims

1. A fluorinated coating for ultra-weather-resistant wrapping tape, characterized in that, Composed of the following components in parts by weight: 45-55 parts of hyperbranched perfluoropolyether diol, 12-13 parts of tetraethyl orthosilicate, 30-40 parts of hexamethylene diisocyanate trimer, 4-6 parts of modified nano-silica, 0.5-1 parts of catalyst dibutyltin dilaurate, and 0.4-0.6 parts of leveling agent BYK-381; The modified nano-silica is perfluorooctyltriethoxysilane modified nano-silica.

2. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 1, characterized in that, The preparation steps of the hyperbranched perfluoropolyether diol are as follows: Step A1: Under a nitrogen atmosphere, add perfluoropolyether diol to a tetrahydrofuran solution, stir to dissolve, heat to 50-70℃, add glycidyl methacrylate and triethylamine, react for 5-7 hours until the reaction is complete, cool to 20-30℃, and distill under reduced pressure to obtain epoxy-terminated perfluoropolyether diol. Step A2: Under a nitrogen atmosphere, epoxy-terminated perfluoropolyether glycol is added to tetrahydrofuran solvent and stirred to dissolve. Hydroxyethyl acrylate and initiator azobisisobutyronitrile are added, the temperature is raised to 60-80℃, and the reaction is carried out for 7-9 hours. The reaction is completed, and the reaction solution is obtained. Step A3: Add the reaction solution to deionized water, stir and mix, add the catalyst triethylamine, heat to 90-110℃, reflux for 3-5 hours, after the reaction is complete, cool to 20-30℃, wash the layers, dry, and distill under reduced pressure to obtain hyperbranched perfluoropolyether diol.

3. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 2, characterized in that, The mass ratio of perfluoropolyether glycol, glycidyl methacrylate and triethylamine in step A1 is 1:0.2-0.24:0.014-0.

016.

4. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 2, characterized in that, In step A2, the mass ratio of epoxy-terminated perfluoropolyether glycol, hydroxyethyl acrylate, and initiator is 1:0.48-0.52:0.008-0.

012.

5. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 2, characterized in that, The mass ratio of the reaction solution to the catalyst in step A3 is 1:0.004-0.

006.

6. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 1, characterized in that, The modified nano-silica is prepared in the following steps: Step B1: Under a nitrogen atmosphere, add perfluorooctyltriethoxysilane to anhydrous ethanol, add deionized water, heat to 20-30℃, stir and hydrolyze for 20-40 min to obtain hydrolysate; Step B2: Add nano-silica to anhydrous ethanol, sonicate for 20-40 min at 400-600 W, add hydrolysate, heat to 50-70℃, stir for 7-9 h at 500-700 rpm, add acetic acid, adjust pH to 5-6, after the reaction is complete, centrifuge, wash, and vacuum dry to obtain modified silica.

7. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 6, characterized in that, The mass ratio of perfluorooctyltriethoxysilane to deionized water in step B1 is 1:0.15-0.

17.

8. The fluorinated coating for ultra-weather-resistant wrapping tape according to claim 6, characterized in that, The mass ratio of nano-silica, anhydrous ethanol and hydrolysate mentioned in step B2 is 1:15.6-16:8-8.

4.

9. A method for preparing a fluorinated coating for ultra-weather-resistant wrapping tape according to any one of claims 1-8, characterized in that, The preparation steps are as follows: Step S1: Add tetraethyl orthosilicate and 0.1 mol / L hydrochloric acid aqueous solution to propylene glycol methyl ether acetate solvent, heat to 50-70℃, react for 1.5-2.5 h, and rotate at 400-600 rpm to obtain a transparent sol; Step S2: Add the hyperbranched perfluorinated polyether glycol and transparent sol to propylene glycol methyl ether acetate solvent, heat to 70-90℃, stir for 2-4 hours at 300-500 rpm, and the reaction is complete to obtain the prepolymer. Step S3: Add modified nano-silica to the prepolymer, heat to 30-40℃, sonicate for 20-40 min at 400-600W, place in a high-speed homogenizer, react for 50-70 min at 1800-2200 rpm, add leveling agent, stir for 10-20 min, reduce the speed to 150-250 rpm, add hexamethylene diisocyanate trimer and catalyst dibutyltin dilaurate, stir for 10-20 min, increase the speed to 700-900 rpm, and obtain fluorinated coating.

10. The method for preparing a fluorinated coating for ultra-weather-resistant wrapping tape according to claim 9, characterized in that, In step S1, the mass ratio of tetraethyl orthosilicate to hydrochloric acid aqueous solution is 1:0.07-0.09; The mass ratio of hyperbranched perfluoropolyether diol to transparent sol in step S2 is 1.7-1.8:1; In step S3, the mass ratio of modified nano-silica, prepolymer, leveling agent, hexamethylene diisocyanate trimer to catalyst is 0.028-0.032:1:0.0028-0.0032:0.21-0.23:0.004-0.006.

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