Weather-resistant polysiloxane silicone rubber glass decoration protective coating and preparation method thereof

Abstract

The application discloses a weather-resistant polysiloxane silicone rubber glass decoration protective coating and a preparation method thereof, and relates to the technical field of protective coatings.The application comprises the following raw materials by mass fraction: 83-100 parts of an epoxy polysiloxane solution, 1.8-2.2 parts of cerium 2-ethylhexanoate, 8-9.5 parts of AG-80 epoxy resin, 36-43 parts of a curing agent, and 2-4 parts of modified cellulose nanocrystals; wherein the modified cellulose nanocrystals are prepared from cellulose nanocrystals, heptadecafluorodecyltrimethoxysilane and MXene quantum dots.The hard and dense coating formed by mixing the epoxy polysiloxane solution, the AG-80 epoxy resin and the curing agent and the like components effectively improves the hardness and salt mist resistance; and the introduction of the modified cellulose nanocrystals and the cerium 2-ethylhexanoate further improves the adhesion, the protection and the weather resistance.Therefore, the application has a more extensive application prospect.

Description

Technical Field

[0001] This invention relates to the field of protective coating technology, specifically to a weather-resistant polysiloxane silicone rubber glass decorative protective coating and its preparation method. Background Technology

[0002] Silicone rubber glass protective coating is a coating material made from elastic polymers with siloxane as the backbone, with added functional fillers and curing agents. Through a cross-linking reaction, it forms a transparent, flexible, and protective film on the glass surface. As a novel coating material, it is widely used due to its excellent protective capabilities and good high and low temperature adaptability, meeting the diverse needs of different application scenarios.

[0003] However, in practical applications, silicone rubber glass protective coatings still suffer from low hardness and poor adhesion, making them prone to scratches or peeling during daily cleaning, damaging the anti-fouling and hydrophobic functional layers. They also exhibit poor resistance to salt spray and UV aging, easily blistering, yellowing, and powdering after prolonged exposure to rain or sun. Therefore, the existing silicone rubber glass protective coatings still need improvement in terms of discoloration prevention, adhesion, protection, weather resistance, and ease of application. Summary of the Invention

[0004] The purpose of this invention is to provide a weather-resistant polysiloxane silicone rubber glass decorative protective coating and its preparation method, thereby solving the following technical problems:

[0005] Existing silicone rubber glass protective coatings still suffer from problems such as easy discoloration, poor adhesion, high construction requirements, poor protection, and poor weather resistance.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A weather-resistant polysiloxane silicone rubber glass decorative protective coating comprises the following raw materials by weight: 83-100 parts epoxy polysiloxane solution, 1.8-2.2 parts cerium 2-ethylhexanoate, 8-9.5 parts AG-80 epoxy resin, 36-43 parts curing agent, and 2-4 parts modified cellulose nanocrystals;

[0008] The modified cellulose nanocrystals were prepared from cellulose nanocrystals, heptadecafluorodecyltrimethoxysilane, and MXene quantum dots.

[0009] Preferably, the epoxy polysiloxane solution is prepared as follows:

[0010] Add anhydrous potassium carbonate to deionized water and stir for 10-30 min. Then add tetrahydrofuran and stir for 20-30 min. Then add silane coupling agent KH-560 under nitrogen atmosphere and react for 36-40 h. After removing tetrahydrofuran by rotary evaporation at 68-75 °C, add dichloromethane and stir for 20-30 min. Finally, add anhydrous magnesium sulfate and stir for 24-30 h. After filtering to remove the precipitate, an epoxy polysiloxane solution is obtained.

[0011] Preferably, the mass ratio of the deionized water, anhydrous potassium carbonate, tetrahydrofuran, silane coupling agent KH-560, dichloromethane, and anhydrous magnesium sulfate is 30-50:0.25-0.37:222-310:118-177:66-99:60-100.

[0012] Preferably, the curing agent is prepared by the following method:

[0013] A1: Add diphenyl chlorophosphate to dichloromethane and stir for 30-60 min to obtain a diphenyl chlorophosphate solution;

[0014] A2: Add diethylenetriamine and triethylamine to dichloromethane and stir for 20-60 min. Then, under a nitrogen atmosphere at 0-5℃, add diphenyl chlorophosphate solution dropwise and react for 10-15 h. After filtration, remove dichloromethane and triethylamine by rotary evaporation at 90-95℃ to obtain the curing agent.

[0015] Preferably, the mass ratio of dichloromethane to diphenyl chlorophosphate in A1 is 66-99:26-39;

[0016] The solution of dichloromethane, diethylenetriamine, triethylamine, and diphenyl chlorophosphate described in A2 is 331-463:10-15:10-15:92-138.

[0017] Preferably, the modified cellulose nanocrystals are prepared by the following method:

[0018] B1: Add cellulose nanocrystals to deionized water and perform ultrasonic dispersion at a power of 200-300W and a frequency of 30-40kHz for 30-60 minutes. Then adjust the pH to 4.5-5.0 with 1mol / L acetic acid solution to obtain a cellulose nanocrystal suspension.

[0019] B2: Add deionized water to anhydrous ethanol and stir for 10-30 min. Then, while stirring, add heptadecafluorodecyltrimethoxysilane dropwise. Adjust the pH to 4.0-4.5 with 1 mol / L acetic acid and stir for 40-60 min at 40-45℃ under a nitrogen atmosphere. After cooling to 20-30℃, add MXene quantum dots and perform ultrasonic dispersion at 200-300W and 30-40kHz for 15-30 min to obtain a mixed hydrolysate.

[0020] B3: Add the mixed hydrolysate dropwise to the cellulose nanocrystal suspension at a rate of 1-5 mL / min. After stirring for 10-30 min, adjust the pH to 8.0-8.5 with 25%-28% ammonia solution. Then, reflux the mixture at 350-450 r / min for 10-15 h under a nitrogen atmosphere at 58-62 °C. After centrifugation at 9000-11000 r / min for 15-30 min, separate the precipitate. Wash the precipitate 3-5 times with anhydrous ethanol-water mixture, then wash it 3-5 times with anhydrous ethanol. Add the precipitate to anhydrous ethanol and perform ultrasonic dispersion at 200-300 W and 30-40 kHz for 10-20 min. Finally, dry the precipitate at 40-45 °C and 5-10 kPa for 20-30 h to obtain modified cellulose nanocrystals.

[0021] Preferably, the mass ratio of deionized water to cellulose nanocrystals in B1 is 100-150:2-3.

[0022] Preferably, the ratio of anhydrous ethanol, deionized water, heptadecafluorodecyltrimethoxysilane, and MXene quantum dots in B2 is 20-30 mL: 5-7 mL: 2-3 mL: 0.1-0.15 g.

[0023] Preferably, the volume ratio of the mixed hydrolysate, cellulose nanocrystal suspension, and anhydrous ethanol in B3 is 27-40:100-150:5-10.

[0024] A method for preparing a weather-resistant polysiloxane silicone rubber glass decorative protective coating includes the following steps:

[0025] Add cerium 2-ethylhexanoate and AG-80 epoxy resin to an epoxy polysiloxane solution and stir at 65-70℃ for 20-30 min. Then add curing agent and modified cellulose nanocrystals and stir at 65-70℃ for 30-60 min to obtain a weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0026] The beneficial effects of this invention are:

[0027] This invention provides a weather-resistant polysiloxane silicone rubber glass decorative protective coating and its preparation method. The invention effectively improves the anti-discoloration ability, adhesion, protection and weather resistance of the silicone rubber glass protective coating through the following method, while reducing the construction requirements.

[0028] (1) The modified cellulose nanocrystals of this invention are rich in hydroxyl groups on their surface, which can form hydrogen bonds with the silanols on the glass substrate surface; the silanol generated by the hydrolysis of heptadecafluorodecyltrimethoxysilane will condense with the hydroxyl groups of the cellulose nanocrystals, and at the same time react with the siloxane bonds of the epoxy polysiloxane in the coating or the hydroxyl groups on the glass surface to form a continuous covalent bond network, reducing interface defects; MXene quantum dots can fill the microscopic gaps between the coating and the substrate, reduce stress concentration, improve the interfacial bonding strength, and further improve the coating adhesion. The addition of cellulose nanocrystals can effectively improve the hardness and scratch resistance of the coating and reduce material shedding during wear; the addition of MXene quantum dots can hinder the crack propagation in the coating and disperse frictional stress, further improving wear resistance; at the same time, the silicon-oxygen network formed by the hydrolysis and condensation of heptadecafluorodecyltrimethoxysilane combines with the cellulose nanocrystals, which can further fill the coating pores, improve density, and reduce wear rate. The nanorod-like structure of cellulose nanocrystals and the layered structure of MXene quantum dots together construct a micro-nano composite surface. Combined with the low surface energy of fluoroalkyl groups, a "lotus leaf effect" is formed, significantly increasing the coating's water contact angle. The high water contact angle of the coating makes it difficult for water-based stains to spread on the coating surface, allowing them to roll off and carry away contaminants. The low surface energy of fluoroalkyl groups reduces the wetting ability of oils, increases the oil contact angle, and reduces the adhesion of oil-based contaminants. The nano-roughness of the coating surface, combined with its hydrophobicity, also ensures that tiny contaminants such as dust can only contact the "peaks" of the coating surface, making them easier to be washed away by rainwater. The strong interfacial bonding between the modified cellulose nanocrystals and the substrate glass can fill the microscopic defects between the coating and substrate interfaces, preventing chloride ion accumulation at the interface and pitting corrosion. The hydroxyl and other functional groups on the surface of MXene quantum dots can complex with metal ions in the glass to form a passivation layer, which can further inhibit corrosion and improve the coating's salt spray resistance. The UV energy conversion capability of MXene quantum dots, combined with the excellent UV fracture resistance of heptadecafluorodecyltrimethoxysilane and the internal stress resistance of cellulose nanocrystal dispersion coating due to photoaging, can effectively improve the aging resistance of the coating.

[0029] (2) The active hydrogen atoms in the amine group of the curing agent of this invention promote the ring-opening reaction of the epoxy groups present in the epoxy polysiloxane and AG-80 epoxy resin, thereby forming a strong cross-linked network, enhancing the mechanical properties of the coating, and improving its overall thermal and chemical stability. The ring-opening of the epoxy groups also forms hydroxyl groups, which form intermolecular hydrogen bonds with the glass surface, effectively improving the coating adhesion. The hydrophobic alkyl chain of the phenoxy group in the curing agent can reduce the surface energy and increase the water contact angle. The curing agent and the fluorosilicone component can reduce the surface energy of the coating, making it difficult for water, oil and other pollutants to adhere; at the same time, the rigid structure of the phosphoryl group can increase the cross-linking density, reduce surface microcracks, and inhibit the penetration of pollutants. The three-dimensional network structure formed by the cross-linking of the curing agent and AG-80 epoxy resin is more compact, and the coating hardness and scratch resistance are enhanced; the rigid benzene ring of the phosphoryl group can inhibit molecular chain slippage and improve wear resistance life. The increase in coating density and water contact angle can reduce the penetration of chloride ions and water; in addition, phosphorus can also form stable phosphorus-oxysilicon bonds with silicon ions on the substrate glass surface, inhibiting substrate corrosion. The phosphoryl group can capture UV-induced free radicals, generate a stable structure, and inhibit chain oxidation reactions; the phenoxy group can absorb some UV energy and convert it into heat energy, reducing the direct photolysis of resin molecules.

[0030] (3) The epoxy groups in the epoxy polysiloxane solution of the present invention can undergo ring-opening reactions with the hydroxyl groups on the glass surface to form covalent bonds; the silanols generated by the hydrolysis of siloxane segments can form hydrogen bonds or covalent bonds with the silicon-oxygen network of the glass to achieve "molecular bridge" connection. The low surface energy of siloxanes and fluoroalkyl groups can reduce the adhesion of non-polar contaminants. The epoxy groups react with AG-80 epoxy resin and curing agent to form a hard and dense three-dimensional cross-linked structure, which reduces coating peeling caused by friction and can also block corrosive media such as chloride ions and water molecules from penetrating into the substrate; the siloxane segments are resistant to hydrolysis, which can avoid coating blistering and peeling caused by water absorption and swelling; the strong chemical bond between the epoxy groups and the substrate can maintain the adhesion between the coating and the glass for a long time and delay corrosion propagation. The siloxane bonds in siloxanes have extremely low absorption of ultraviolet light, making them less susceptible to photodegradation. The siloxane network can scatter or reflect some ultraviolet light, reducing its direct attack on the aromatic rings in AG-80 epoxy resin. Siloxanes can synergistically capture free radicals with cerium 2-ethylhexanoate, inhibiting photooxidation reactions.

[0031] (4) The cerium 2-ethylhexanoate of this invention can accelerate the hydrolysis and polycondensation of silane coupling agents, while catalyzing the ring-opening reaction of epoxy groups with the hydroxyl groups of the substrate, improving the chemical bonding strength between the coating and the glass substrate, reducing interface defects, and significantly enhancing adhesion. It catalyzes the hydrolysis and polycondensation of heptadecafluorodecyltrimethoxysilane, promoting the directional enrichment of fluorine-containing groups on the coating surface, fully exposing the hydrophobic properties of fluorine groups, effectively increasing the water contact angle, reducing surface energy, and making it more difficult for pollutants to be adsorbed. It can also accelerate the crosslinking reaction between epoxy polysiloxane and AG-80, increase the crosslinking density, reduce the residue of unreacted active groups, and improve the coating hardness, wear resistance, and salt spray resistance. Its free radical scavenging ability can also inhibit the oxidative degradation of resin caused by ultraviolet light, preventing yellowing and chalking of the coating.

[0032] (5) The AG-80 epoxy resin molecule of this invention contains four epoxy groups, which can undergo a ring-opening reaction with the silanol groups on the glass surface, and simultaneously form crosslinks with the epoxy groups in the epoxy polysiloxane, thereby significantly increasing the number of chemical bonding points between the coating and the substrate and significantly improving adhesion. Its aromatic rings and high crosslinking density together improve the coating's resistance to deformation, thereby improving the coating's hardness and wear resistance. The dense crosslinked network formed by its reaction with curing agents can effectively prevent the penetration of chloride ions and water.

[0033] Therefore, the weather-resistant polysiloxane silicone rubber glass decorative protective coating prepared by this invention not only has low construction requirements, but also has excellent anti-discoloration ability, adhesion, protection and weather resistance, as well as a wider range of application prospects. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Unless otherwise specified, the following information pertains to some of the raw materials used in the following embodiments and comparative examples of this invention:

[0036] MXene quantum dots were purchased from Xi'an Ruixi Biotechnology Co., Ltd., CAS: 12316-56-2; cerium 2-ethylhexanoate was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., item number: C419796; AG-80 epoxy resin was purchased from Wuhan Xinxinjiali Biotechnology Co., Ltd., item number: 28768-32-3.

[0037] Example 1: A method for preparing a weather-resistant polysiloxane silicone rubber glass decorative protective coating is as follows:

[0038] S1: Add 2g of cellulose nanocrystals to 100mL of deionized water and perform ultrasonic dispersion at 200W and 30kHz for 30min. Then adjust the pH to 4.5 with 1mol / L acetic acid solution to obtain a cellulose nanocrystal suspension.

[0039] S2: Add 5 mL of deionized water to 20 mL of anhydrous ethanol and stir for 10 min. Then, while stirring, add 2 mL of heptadecafluorodecyltrimethoxysilane dropwise. Adjust the pH to 4.0 with 1 mol / L acetic acid and stir for 40 min at 40 °C under a nitrogen atmosphere. After cooling to 20 °C, add 0.1 g of MXene quantum dots and perform ultrasonic dispersion at 200 W and 30 kHz for 15 min to obtain a mixed hydrolysate.

[0040] S3: 27 mL of mixed hydrolysate was added dropwise to 100 mL of cellulose nanocrystal suspension at a rate of 1 mL / min. After stirring for 10 min, the pH was adjusted to 8.0 with 25% ammonia. Then, the mixture was stirred and refluxed at 350 r / min for 10 h under a nitrogen atmosphere at 58 °C. After centrifugation at 9000 r / min for 15 min, the precipitate was separated. The precipitate was washed three times with anhydrous ethanol-water mixture (volume ratio 3:1) and then washed three times with anhydrous ethanol. The precipitate was then added to 5 mL of anhydrous ethanol and ultrasonically dispersed at 200 W and 30 kHz for 10 min. Finally, the precipitate was dried at 40 °C and 5 kPa for 20 h to obtain modified cellulose nanocrystals.

[0041] S4: Add 26g of diphenyl chlorophosphate to 50mL of dichloromethane and stir for 30min to obtain a diphenyl chlorophosphate solution;

[0042] S5: Add 10g of diethylenetriamine and 10g of triethylamine to 250mL of dichloromethane and stir for 20min. Then, add 92g of diphenyl chlorophosphate solution dropwise under a nitrogen atmosphere at 0℃ and react for 10h. After filtration, evaporate to 36g at 90℃ to obtain the curing agent.

[0043] S6: Add 0.25g of anhydrous potassium carbonate to 30g of deionized water and stir for 10min. Then add 250mL of tetrahydrofuran and stir for 20min. Then add 118g of silane coupling agent KH-560 under nitrogen atmosphere and react for 36h. After rotary evaporation at 68℃ to 148g, add 50mL of dichloromethane and stir for 20min. Finally, add 60g of anhydrous magnesium sulfate and filter to remove the precipitate after 24h to obtain an epoxy polysiloxane solution.

[0044] S7: Add 1.8g of cerium 2-ethylhexanoate and 8g of AG-80 epoxy resin to 83g of epoxy polysiloxane solution and stir at 65℃ for 20min. Then add 36g of curing agent and 2g of modified cellulose nanocrystals and stir at 65℃ for 30min to obtain weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0045] Example 2: A method for preparing a weather-resistant polysiloxane silicone rubber glass decorative protective coating is as follows:

[0046] S1: Add 2.5g of cellulose nanocrystals to 125mL of deionized water and perform ultrasonic dispersion at 250W and 35kHz for 45min. Then adjust the pH to 4.8 with 1mol / L acetic acid solution to obtain a cellulose nanocrystal suspension.

[0047] S2: Add 6 mL of deionized water to 25 mL of anhydrous ethanol and stir for 20 min. Then, while stirring, add 2.5 mL of heptadecafluorodecyltrimethoxysilane dropwise. Adjust the pH to 4.3 with 1 mol / L acetic acid and stir at 43 °C under a nitrogen atmosphere for 50 min. After cooling to 25 °C, add 0.13 g of MXene quantum dots and perform ultrasonic dispersion at 250 W and 35 kHz for 25 min to obtain a mixed hydrolysate.

[0048] S3: 33.5 mL of mixed hydrolysate was added dropwise to 125 mL of cellulose nanocrystal suspension at a rate of 3 mL / min. After stirring for 20 min, the pH was adjusted to 8.3 with 27% ammonia solution. Then, the mixture was stirred and refluxed at 400 r / min for 13 h under a nitrogen atmosphere at 60 °C. After centrifugation at 10000 r / min for 25 min, the precipitate was separated. The precipitate was washed four times with anhydrous ethanol-water mixture (volume ratio 3:1) and then washed four times with anhydrous ethanol. The precipitate was then added to 8 mL of anhydrous ethanol and ultrasonically dispersed at 250 W and 35 kHz for 15 min. Finally, the precipitate was dried at 43 °C and 8 kPa for 25 h to obtain modified cellulose nanocrystals.

[0049] S4: Add 32.5g of diphenyl chlorophosphate to 57.5mL of dichloromethane and stir for 45min to obtain a diphenyl chlorophosphate solution;

[0050] S5: Add 12.5g of diethylenetriamine and 12.5g of triethylamine to 300mL of dichloromethane and stir for 40min. Then, add 115g of diphenyl chlorophosphate solution dropwise under a nitrogen atmosphere at 3℃ and react for 13h. After filtration, evaporate to 45g at 93℃ to obtain the curing agent.

[0051] S6: Add 0.31g of anhydrous potassium carbonate to 40g of deionized water and stir for 20min. Then add 300mL of tetrahydrofuran and stir for 25min. Then add 147.5g of silane coupling agent KH-560 under a nitrogen atmosphere and react for 38h. After rotary evaporation at 71℃ to 187.5g, add 62.5mL of dichloromethane and stir for 25min. Finally, add 80g of anhydrous magnesium sulfate and filter to remove the precipitate after 27h to obtain an epoxy polysiloxane solution.

[0052] S7: Add 2g of cerium 2-ethylhexanoate and 8.7g of AG-80 epoxy resin to 91.5g of epoxy polysiloxane solution and stir at 68℃ for 25min. Then add 39.5g of curing agent and 3g of modified cellulose nanocrystals and stir at 68℃ for 45min to obtain weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0053] Example 3: A method for preparing a weather-resistant polysiloxane silicone rubber glass decorative protective coating is as follows:

[0054] S1: Add 3g of cellulose nanocrystals to 150mL of deionized water and perform ultrasonic dispersion at 300W and 40kHz for 60min. Then adjust the pH to 5.0 with 1mol / L acetic acid solution to obtain a cellulose nanocrystal suspension.

[0055] S2: Add 7 mL of deionized water to 30 mL of anhydrous ethanol and stir for 30 min. Then, while stirring, add 3 mL of heptadecafluorodecyltrimethoxysilane dropwise. Adjust the pH to 4.5 with 1 mol / L acetic acid and stir at 45 °C under a nitrogen atmosphere for 60 min. After cooling to 30 °C, add 0.15 g of MXene quantum dots and perform ultrasonic dispersion at 300 W and 40 kHz for 30 min to obtain a mixed hydrolysate.

[0056] S3: 40 mL of mixed hydrolysate was added dropwise to 150 mL of cellulose nanocrystal suspension at a rate of 5 mL / min. After stirring for 30 min, the pH was adjusted to 8.5 with 28% ammonia solution. Then, the mixture was stirred and refluxed at 450 r / min for 15 h under a nitrogen atmosphere at 62 °C. After centrifugation at 11000 r / min for 30 min, the precipitate was separated. The precipitate was washed 5 times with anhydrous ethanol-water mixture (volume ratio 3:1) and then washed 5 times with anhydrous ethanol. The precipitate was then added to 10 mL of anhydrous ethanol and ultrasonically dispersed at 300 W and 40 kHz for 20 min. Finally, the precipitate was dried at 45 °C and 10 kPa for 30 h to obtain modified cellulose nanocrystals.

[0057] S4: Add 39g of diphenyl chlorophosphate to 75mL of dichloromethane and stir for 60min to obtain a diphenyl chlorophosphate solution;

[0058] S5: Add 15g of diethylenetriamine and 15g of triethylamine to 350mL of dichloromethane and stir for 60min. Then, add 138g of diphenyl chlorophosphate solution dropwise under a nitrogen atmosphere at 5℃ and react for 15h. After filtration, evaporate to 54g at 95℃ to obtain the curing agent.

[0059] S6: Add 0.37g of anhydrous potassium carbonate to 50g of deionized water and stir for 30min. Then add 350mL of tetrahydrofuran and stir for 30min. Then add 177g of silane coupling agent KH-560 under nitrogen atmosphere and react for 40h. After rotary evaporation at 75℃ to 242g, add 75mL of dichloromethane and stir for 30min. Finally, add 100g of anhydrous magnesium sulfate and filter to remove the precipitate after 30h to obtain an epoxy polysiloxane solution.

[0060] S7: Add 2.2g of cerium 2-ethylhexanoate and 9.5g of AG-80 epoxy resin to 100g of epoxy polysiloxane solution and stir at 70℃ for 30min. Then add 43g of curing agent and 4g of modified cellulose nanocrystals and stir at 70℃ for 60min to obtain weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0061] Comparative Example 1:

[0062] Compared with Example 1, this comparative example only did not add "heptadecyltrimethoxysilane" during the preparation process of S2. All other steps and parameters were the same, and will not be repeated here. The final product was a weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0063] Comparative Example 2:

[0064] Compared with Example 1, this comparative example only did not add "MXene quantum dots" in the preparation process of S2. All other steps and parameters were the same, and will not be repeated here. The final product is a weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0065] Comparative Example 3:

[0066] Compared with Example 1, this comparative example only replaces the "modified cellulose nanocrystals" added in the preparation process of S7 with "cellulose nanocrystals". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a weather-resistant polysiloxane silicone rubber glass decorative protective coating is obtained.

[0067] Comparative Example 4:

[0068] Compared with Example 1, this comparative example only omits the addition of "modified cellulose nanocrystals" in the preparation process of S7. All other steps and parameters are the same, and will not be repeated here. The final product is a weather-resistant polysiloxane silicone rubber glass decorative and protective coating.

[0069] Comparative Example 5:

[0070] Compared with Example 1, this comparative example only omits the addition of "2-ethylhexanoate cerium" in the preparation process of S7. All other steps and parameters are the same, and will not be repeated here. The final product is a weather-resistant polysiloxane silicone rubber glass decorative protective coating.

[0071] Comparative Example 6:

[0072] Compared with Example 1, this comparative example only replaces the "83g epoxy polysiloxane solution" added in the preparation process of S7 with "24g of AG-80 epoxy resin dissolved in 22.5mL of dichloromethane to obtain AG-80 epoxy resin solution". All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a weather-resistant polysiloxane silicone rubber glass decorative protective coating is obtained.

[0073] Comparative Example 7:

[0074] Compared with Example 1, this comparative example only replaces "8g of AG-80 epoxy resin" in the preparation process of S7 with "27.7g of epoxy polysiloxane solution" prepared in S6. All other steps and parameters are the same, and will not be repeated in this comparative example. Finally, a weather-resistant polysiloxane silicone rubber glass decorative protective coating is obtained.

[0075] Performance testing:

[0076] The weather-resistant polysiloxane silicone rubber glass decorative protective coatings prepared in Examples 1-3 and Comparative Examples 1-7 of this invention were applied at a concentration of 0.05 g / cm³. 2 The silicone rubber-coated glass sample was uniformly spin-coated onto a glass plate and cured at 90°C for 8 hours.

[0077] Adhesion determination:

[0078] Referring to GB / T 9286-2021 "Cross-cut test of paints and varnishes", the adhesion (grade) of each coating on the silicone rubber coated glass sample prepared by the weather-resistant polysiloxane silicone rubber glass decorative protective coating prepared by Examples 1-3 and Comparative Examples 1-7 of this invention was determined. The test results are shown in Table 1.

[0079] Determination of oil contact angle and water contact angle:

[0080] Referring to GB / T 24368-2009 "Determination of contact angle of paint and varnish film", the oil contact angle (diiodomethane) and water contact angle (deionized water) of each coating on the silicone rubber coated glass sample prepared by the weather-resistant polysiloxane silicone rubber glass decorative protective coating prepared by Examples 1-3 and Comparative Examples 1-7 of this invention were determined. The test results are shown in Table 1.

[0081] Salt spray resistance test:

[0082] Referring to GB / T 10125-2021 "Artificial Atmosphere Corrosion Test - Salt Spray Test" standard, the silicone rubber coated glass samples were sealed with epoxy putty, and then placed in a salt spray test chamber (JAY-1127, Zhuhai Jiayi Testing Equipment Co., Ltd.). At 35℃, a 24-hour salt spray and 24-hour drying cycle test was conducted using a 5% sodium chloride solution. The presence of blistering or other changes was measured after 50-40 hours of testing for each sample. The salt spray resistance of the silicone rubber coated glass samples prepared with the weather-resistant polysiloxane silicone rubber glass decorative protective coatings of Examples 1-3 and Comparative Examples 1-7 was determined using the above method. The test results are shown in Table 1.

[0083] Abrasion resistance testing:

[0084] Referring to GB / T 1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotary Rubber Grinding Wheel Method", the wear mass (mg) of silicone rubber coated glass samples prepared by the weather-resistant polysiloxane silicone rubber glass decorative protective coatings prepared in Examples 1-3 and Comparative Examples 1-7 of this invention was measured under a load of 1000g and a wear cycle of 1000r to reflect the abrasion resistance. The test results are shown in Table 1.

[0085] Hardness measurement:

[0086] Referring to GB / T 6739—2022 "Determination of Hardness of Paint Film by Pencil Method", the hardness (grade) of the coating on the silicone rubber coated glass sample prepared by the weather-resistant polysiloxane silicone rubber glass decorative protective coating prepared in Examples 1-3 and Comparative Examples 1-7 of this invention was determined. The test results are shown in Table 1.

[0087] Table 1: Basic performance test results of Examples 1-3 and Comparative Examples 1-7

[0088]

[0089] Determination of the yellowing index:

[0090] Referring to GB / T 5211.16-2006 "Determination of thermosetting coatings of colorless and colored powder coatings and varnishes", the silicone rubber coated glass samples prepared with the weather-resistant polysiloxane silicone rubber glass decorative protective coatings of Examples 1-3 and Comparative Examples 1-7 of this invention were tested at an irradiance of 0.51 W / m². 2 The yellowing index after 1000 hours of exposure under the following test conditions: (340nm), blackboard temperature 65℃, relative humidity 50%, and cycling conditions of first 102 min of light exposure followed by 18 min of spraying. The test results are shown in Table 2.

[0091] Determination of resistance to chalking:

[0092] Referring to GB / T 1766-2008 "Rating Method for Aging of Paint and Varnish Coatings", the silicone rubber coated glass samples prepared with the weather-resistant polysiloxane silicone rubber glass decorative protective coatings of Examples 1-3 and Comparative Examples 1-7 of this invention were tested at an irradiance of 0.51 W / m². 2 The chalking level after exposure for 1000 hours under the following test conditions: (340nm), blackboard temperature 65℃, relative humidity 50%, and cycling conditions: first light exposure for 102 minutes followed by spraying for 18 minutes, is used to reflect its chalking resistance (level). The test results are shown in Table 2.

[0093] Measurement of water contact angle after aging:

[0094] Referring to GB / T 24368-2009 "Determination of Contact Angle of Paint and Varnish Films", the contact angle of the silicone rubber coated glass samples prepared with the weather-resistant polysiloxane silicone rubber glass decorative protective coatings of Examples 1-3 and Comparative Examples 1-7 of this invention was measured at an irradiance of 0.51 W / m². 2 The water contact angle (°) after 1000h exposure under the following test conditions: (340nm), blackboard temperature 65℃, relative humidity 50%, and cyclic conditions of first 102min of light exposure followed by 18min of spraying. The results are shown in Table 2.

[0095] Table 2: Aging resistance test results of Examples 1-3 and Comparative Examples 1-7

[0096]

[0097] Data Analysis:

[0098] As can be seen from Tables 1 and 2, the weather-resistant polysiloxane silicone rubber glass decorative protective coating prepared in the embodiments of the present invention has excellent adhesion, water resistance, oil resistance, salt spray resistance, abrasion resistance, hardness and aging resistance.

[0099] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A weather-resistant polysiloxane silicone rubber glass decorative and protective coating, characterized in that, The raw materials include the following parts by weight: 83-100 parts epoxy polysiloxane solution, 1.8-2.2 parts cerium 2-ethylhexanoate, 8-9.5 parts AG-80 epoxy resin, 36-43 parts curing agent, and 2-4 parts modified cellulose nanocrystals; The preparation method of the epoxy polysiloxane solution is as follows: Add anhydrous potassium carbonate to deionized water and stir for 10-30 min. Then add tetrahydrofuran and stir for 20-30 min. Then add silane coupling agent KH-560 under nitrogen atmosphere and react for 36-40 h. After removing tetrahydrofuran by rotary evaporation, add dichloromethane and stir for 20-30 min. Finally, add anhydrous magnesium sulfate and stir for 24-30 h. After filtering to remove the precipitate, an epoxy polysiloxane solution is obtained. The curing agent is prepared as follows: A1: Add diphenyl chlorophosphate to dichloromethane and stir for 30-60 min to obtain a diphenyl chlorophosphate solution; A2: Add diethylenetriamine and triethylamine to dichloromethane and stir for 20-60 min. Then, add diphenyl chlorophosphate solution dropwise under a nitrogen atmosphere at 0-5℃ and react for 10-15 h. After filtration, remove dichloromethane and triethylamine by rotary evaporation to obtain the curing agent. The modified cellulose nanocrystals are prepared as follows: B1: Add cellulose nanocrystals to deionized water and disperse them ultrasonically, then adjust the pH to 4.5-5.0 to obtain a cellulose nanocrystal suspension; B2: Add deionized water to anhydrous ethanol and stir for 10-30 min. Then, while stirring, add heptadecafluorodecyltrimethoxysilane dropwise to adjust the pH to 4.0-4.

5. Stir at 40-45℃ under a nitrogen atmosphere for 40-60 min. After cooling, add MXene quantum dots and disperse by ultrasonication to obtain a mixed hydrolysate. B3: Add the mixed hydrolysate dropwise into the cellulose nanocrystal suspension, stir for 10-30 min, adjust the pH to 8.0-8.5, then stir and reflux for 10-15 h under a nitrogen atmosphere at 58-62℃, centrifuge and wash the precipitate, add it to anhydrous ethanol and perform ultrasonic dispersion and drying to obtain modified cellulose nanocrystals.

2. The weather-resistant polysiloxane silicone rubber glass decorative and protective coating according to claim 1, characterized in that, In the preparation of the epoxy polysiloxane solution, the mass ratio of deionized water, anhydrous potassium carbonate, tetrahydrofuran, silane coupling agent KH-560, dichloromethane, and anhydrous magnesium sulfate is 30-50:0.25-0.37:222-310:118-177:66-99:60-100.

3. The weather-resistant polysiloxane silicone rubber glass decorative and protective coating according to claim 1, characterized in that, The mass ratio of dichloromethane to diphenyl chlorophosphate in A1 is 66-99:26-39; The solution of dichloromethane, diethylenetriamine, triethylamine, and diphenyl chlorophosphate described in A2 is 331-463:10-15:10-15:92-138.

4. The weather-resistant polysiloxane silicone rubber glass decorative and protective coating according to claim 1, characterized in that, The mass ratio of deionized water to cellulose nanocrystals described in B1 is 100-150:2-3.

5. The weather-resistant polysiloxane silicone rubber glass decorative and protective coating according to claim 1, characterized in that, The amounts of anhydrous ethanol, deionized water, heptadecafluorodecyltrimethoxysilane, and MXene quantum dots described in B2 are 20-30 mL: 5-7 mL: 2-3 mL: 0.1-0.15 g.

6. The weather-resistant polysiloxane silicone rubber glass decorative and protective coating according to claim 1, characterized in that, The volume ratio of the mixed hydrolysate, cellulose nanocrystal suspension, and anhydrous ethanol described in B3 is 27-40:100-150:5-10.

7. A method for preparing a weather-resistant polysiloxane silicone rubber glass decorative protective coating according to any one of claims 1-6, characterized in that, Includes the following steps: Add cerium 2-ethylhexanoate and AG-80 epoxy resin to an epoxy polysiloxane solution and stir at 65-70℃ for 20-30 min. Then add curing agent and modified cellulose nanocrystals and stir at 65-70℃ for 30-60 min to obtain a weather-resistant polysiloxane silicone rubber glass decorative protective coating.

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