Temperature-resistant and weather-resistant sealant and preparation method thereof

Abstract

The present application relates to a kind of temperature-resistant weather sealant and its preparation method, it relates to sealant technical field, by weight parts, including following raw materials are made: PVC resin powder 35-45 parts, composite plasticizer 30-40 parts, composite filler 30-40 parts, cellulose nanocrystal 0.5-1.5 parts, composite stabilizer 3-5 parts, crosslinking agent 1-2 parts, vinyl fluorosilicone oil 3-5 parts, (3,6-diamino-9-azinyl) boronic acid 0.3-0.8 parts, coupling agent 1.5-2.5 parts, pigment white 3-5 parts.The sealant temperature resistance and weather resistance are excellent, and bonding performance is good.

Description

Technical Field

[0001] This invention relates to the field of sealant technology, and in particular to a temperature- and weather-resistant sealant and its preparation method. Background Technology

[0002] As a commonly used functional material, sealant is indispensable in fields such as building curtain walls, automotive engine compartments, and electronic packaging. Its performance directly affects the safety and service life of products. Among its many properties, temperature resistance and weather resistance are key indicators for measuring product quality. Sealants with excellent temperature and weather resistance have become a mandatory requirement for sealant products in high-end equipment manufacturing and large-scale engineering construction.

[0003] Traditional sealants such as silicone sealant and polyurethane sealant have good sealing performance at room temperature, but they are prone to cracking, yellowing and reduced bonding strength under extreme temperatures (such as below -40℃ or above 150℃) and harsh climatic conditions (such as long-term ultraviolet radiation, acid and alkali corrosion, and thermal cycling), making it difficult to meet the needs of high-end applications.

[0004] Currently, most heat-resistant sealants on the market rely on silicone rubber systems, which improve heat resistance by introducing phenyl, fluorine, and other groups. However, these materials are expensive and offer limited improvement in weather resistance; long-term outdoor use can lead to performance degradation due to UV aging. Polyvinyl chloride (PVC)-based sealants, on the other hand, are widely used in the low-end market due to their low cost and excellent processing performance. However, their temperature resistance (typically operating at temperatures <80℃) and weather resistance (susceptible to photo-oxidative aging) have become bottlenecks restricting their development towards high-end products.

[0005] For example, Chinese invention patent CN115785857B discloses a high-temperature curing PVC weld sealant, which comprises the following components by weight: 5-15 parts PVC resin; 10-20 parts liquid rubber; 10-25 parts plasticizer; 3-8 parts adhesion promoter; 20-30 parts nanofiller; 15-30 parts heavy calcium carbonate; 0.5-2 parts heat stabilizer; 0.5-2 parts masking agent; and 2-5 parts moisture absorber. This invention provides a high-temperature curing PVC weld sealant that, by introducing liquid rubber and reducing the proportions of plasticizer and PVC resin, uses polyurethane as an adhesion promoter and tin maleate as a heat stabilizer, and adjusts the component content, resulting in a significant improvement in the adhesion of this weld sealant to the steel plate compared to the weld sealant in the comparative example. The curing temperature of the weld adhesive in this solution has been significantly improved, reaching a maximum of 220℃; it meets the compatibility requirements for high-temperature curing powder coatings, and the powder coatings will not exhibit sagging or oxidation. After high-temperature curing, it exhibits high strength, does not yellow or crack, and has good adhesion. However, its low-temperature resistance and weather resistance still need further improvement.

[0006] It is evident that developing a high-temperature and weather-resistant sealant with excellent temperature and weather resistance and good adhesion, as well as its preparation method, is of great practical significance. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a temperature-resistant and weather-resistant sealant with excellent temperature resistance, weather resistance, and good adhesion, as well as its preparation method.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is a temperature-resistant and weather-resistant sealant, which, by weight, comprises the following raw materials: 35-45 parts of PVC resin powder, 30-40 parts of composite plasticizer, 30-40 parts of composite filler, 0.5-1.5 parts of cellulose nanocrystals, 3-5 parts of composite stabilizer, 1-2 parts of crosslinking agent, 3-5 parts of vinyl fluorosilicone oil, 0.3-0.8 parts of (3,6-diamino-9-acridyl)boric acid, 1.5-2.5 parts of coupling agent, and 3-5 parts of pigment white.

[0009] Preferably, the PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of (1-2):(0.8-1.2):(3-5).

[0010] Preferably, in the bimodal polyvinyl chloride paste resin, small particles with a particle size of 0.2~0.7μm account for 5~20%, and the remainder are large particles with a particle size of about 1μm.

[0011] Preferably, the source of the bimodal polyvinyl chloride paste resin is not particularly required. In one embodiment of the present invention, the bimodal polyvinyl chloride paste resin is prepared according to the method of Chinese Invention Patent Example 1 with authorization announcement number CN105440219B.

[0012] Preferably, the composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetyl citrate in a mass ratio of (3-5):(1-3):2.

[0013] Preferably, the composite filler is a mixture of graphene-modified nano-calcium carbonate and needle-shaped wollastonite powder in a mass ratio of (3-5):(2-3).

[0014] Preferably, the preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.4-0.6 mol / L calcium chloride solution to a reaction vessel, heating to 58-62℃, stirring at a rate of 480-520 r / min, slowly adding 0.4-0.6 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 8-9, and reacting for 30-35 min; controlling the reaction temperature at 70℃, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 80-85℃ for 3-5 h to obtain graphene-modified nano-calcium carbonate.

[0015] Preferably, the mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3.

[0016] Preferably, the concentration of the graphene dispersion is 0.5 mg / mL.

[0017] Preferably, the graphene is a single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm.

[0018] Preferably, the aspect ratio of the needle-shaped wollastonite powder is (15-18):1, and the particle size is 1500-2500 mesh.

[0019] Preferably, the cellulose nanocrystals have a diameter of 10-50 nm, a length of 200-500 nm, and are of model number TL-003.

[0020] Preferably, the composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:(0.3-0.5).

[0021] Preferably, the calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2.

[0022] Preferably, the heat-resistant modifier is Kanekachi A-15 from Japan.

[0023] Preferably, the hydrotalcite is ALCAMIZER® 1-C hydrotalcite.

[0024] Preferably, the crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of (1-2):1.

[0025] Preferably, the vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019.

[0026] Preferably, the coupling agent is a silane coupling agent KH560.

[0027] Preferably, the pigment white is rutile titanium dioxide R902.

[0028] Another object of the present invention is to provide a method for preparing the aforementioned temperature-resistant and weather-resistant sealant, comprising the following steps: Step S1, Mixing: Pump the liquid material into the mixing vessel using a metering pump, and add the solid material by weight; ultrasonically disperse for 20-30 minutes, and then stir at 1000-1300 rpm for 10-15 minutes; Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank for 18-22 hours, and then vacuumed for 30-40 minutes under a vacuum pressure of -0.05Mpa~-0.1MPa. Then, the product is filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant.

[0029] Preferably, the ultrasonic power of the ultrasonic dispersion in step S1 is 300W and the frequency is 40kHz.

[0030] Due to the application of the above technical solution, the present invention has the following beneficial effects: (1) The method for preparing the temperature-resistant and weather-resistant sealant disclosed in this invention is simple, easy to operate and control, has high preparation efficiency and finished product qualification rate, low dependence on equipment, easy to large-scale industrial production, and has high promotion and application value.

[0031] (2) The temperature-resistant and weather-resistant sealant disclosed in this invention, by weight, comprises the following raw materials: 35-45 parts PVC resin powder, 30-40 parts composite plasticizer, 30-40 parts composite filler, 0.5-1.5 parts cellulose nanocrystals, 3-5 parts composite stabilizer, 1-2 parts crosslinking agent, 3-5 parts vinyl fluorosilicone oil, 0.3-0.8 parts (3,6-diamino-9-acridyl)boric acid, 1.5-2.5 parts coupling agent, and 3-5 parts pigment white. Through the synergistic effect of the various raw materials, the sealant exhibits excellent temperature resistance and weather resistance, as well as good adhesion.

[0032] (3) The temperature-resistant and weather-resistant sealant disclosed in this invention is made by compounding PA1384, PCMA-12 and a specific bimodal polyvinyl chloride paste resin in a specific ratio. By utilizing the complementary properties of different PVC resins (such as the toughness of PA1384 and the heat resistance of PCMA-12) and the "filling effect" of bimodal particle size (small particles fill the gaps between large particles), the density, processing fluidity and mechanical stability of the resin matrix are significantly improved. Compared with single PVC resin, this compound system is not easy to soften at high temperature and is not easy to crack at low temperature, providing core support for the wide temperature range stability of the sealant. Epoxidized soybean oil (plasticizer + stabilizer), trioctyl trimellitate (high temperature resistance), and tributyl acetylacetonate (good compatibility) are compounded in a specific ratio, solving the problem that "temperature resistance and compatibility cannot be obtained simultaneously" of traditional single plasticizers. This system maintains stable plasticizing effects over a wide temperature range of -40 to 160℃, avoiding hardening caused by plasticizer migration at high temperatures and embrittlement due to insufficient plasticization at low temperatures, significantly broadening the applicable temperature range of the sealant. Cellulose nanocrystals possess a highly crystalline rod-like structure. Numerous hydroxyl groups in their molecular chains can form a hydrogen bond network with PVC molecular chains, vinyltriethoxysilane, and silanol groups generated by the hydrolysis of coupling agents. This hydrogen bonding restricts the thermal motion of PVC molecular chains at high temperatures, increasing the glass transition temperature of the sealant. Simultaneously, the high aspect ratio of cellulose nanocrystals allows them to form a "rigid skeleton" in the matrix, synergistically constructing a dual support structure with other raw materials, reducing molecular chain slippage at high temperatures. Cellulose nanocrystals exhibit strong ultraviolet scattering, forming a "nanoscale-micrometer scale" dual ultraviolet shielding system with their white color, significantly improving the ultraviolet shielding rate. Furthermore, the hydroxyl groups on their surface can combine with free radicals, inhibiting the photo-oxidation reaction of PVC molecular chains. These hydroxyl groups also reduce interfacial energy, improving the uniformity of filler dispersion in the PVC matrix.

[0033] (4) The temperature-resistant and weather-resistant sealant disclosed in this invention is composed of graphene-modified nano-calcium carbonate and acicular wollastonite powder mixed in a mass ratio of (3-5):(2-3). The graphene sheets and acicular wollastonite form a three-dimensional conductive and thermally conductive network, which not only significantly improves the thermal conductivity (accelerating uniform temperature transfer), but also improves mechanical properties through the "crack bridging" effect. At the same time, the free radical scavenging ability of graphene reduces the photoaging rate. The calcium-zinc composite stabilizer (environmentally friendly stabilizer), hydrotalcite (absorbing HCl), β-diketone (auxiliary stabilizer), and heat-resistant modifier (Kanebuchi A-15 from Japan) work synergistically to construct a three-dimensional stable network that "inhibits degradation, absorbs harmful substances, and enhances heat resistance." Compared with traditional lead salts or single stabilizers, this system can increase the thermal decomposition temperature of PVC and effectively resist aging caused by ultraviolet radiation and oxidation.

[0034] (5) The temperature and weather resistant sealant disclosed in this invention introduces the weather resistance (UV resistance and chemical corrosion resistance) of fluorine element into vinyl fluorosilicone oil and the high and low temperature resistance of silicone oil, so that the sealant can still maintain its elasticity under harsh environments such as strong UV and high humidity, solving the problem of traditional sealants "hardening and losing adhesion after outdoor aging"; the special structure of (3,6-diamino-9-acridyl)boric acid gives it antioxidant and auxiliary stabilizing effects, further delaying the degradation of materials; rutile titanium dioxide R902 efficiently reflects UV rays, reduces substrate aging, and forms a synergistic effect of "UV shielding + weather resistance enhancement" with fluorosilicone oil. Detailed Implementation

[0035] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0036] A temperature- and weather-resistant sealant, by weight, comprises the following raw materials: 35 parts PVC resin powder, 30 parts composite plasticizer, 30 parts composite filler, 0.5 parts cellulose nanocrystals, 3 parts composite stabilizer, 1 part crosslinking agent, 3 parts vinyl fluorosilicone oil, 0.3 parts (3,6-diamino-9-acridyl)boric acid, 1.5 parts coupling agent, and 3 parts pigment white.

[0037] The PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of 1:0.8:3; the bimodal polyvinyl chloride paste resin is prepared according to the method of Example 1 of Chinese Invention Patent No. CN105440219B.

[0038] The composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetyl citrate in a mass ratio of 3:1:2; the composite filler is a mixture of graphene-modified nano-calcium carbonate and needle-shaped wollastonite powder in a mass ratio of 3:2.

[0039] The preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.4 mol / L calcium chloride solution to a reaction vessel, heating to 58℃, stirring at 480 r / min, slowly adding 0.4 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 8, and reacting for 30 min; controlling the reaction temperature at 70℃, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 80℃ for 3 h to obtain graphene-modified nano-calcium carbonate; the mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3; the concentration of the graphene dispersion is 0.5 mg / mL; the graphene is single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm.

[0040] The needle-shaped wollastonite powder has an aspect ratio of 15:1 and an average particle size of 1500 mesh; the cellulose nanocrystals have a diameter of 10-50 nm and a length of 200-500 nm, and are designated as TL-003; the composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:0.3; the calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2; the heat-resistant modifier is Kanekachi A-15 (Japan); the hydrotalcite is ALCAMIZER® 1-C hydrotalcite; the crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of 1:1; the vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019; the coupling agent is silane coupling agent KH560; and the pigment white is rutile titanium dioxide R902.

[0041] A method for preparing the aforementioned temperature-resistant and weather-resistant sealant includes the following steps: Step S1, Mixing: The liquid material is pumped into the mixing vessel by metering pump, and the solid material is added by weight; ultrasonic dispersion for 20 min, and then stirred at 1000 rpm for 10 min; the ultrasonic power of the ultrasonic dispersion is 300W and the frequency is 40kHz. Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank and left for 18 hours. Then, it is vacuumed for 30 minutes under a vacuum pressure of -0.05 MPa. Next, the product is filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant. Example 2

[0042] A temperature- and weather-resistant sealant, by weight, comprises the following raw materials: 37 parts PVC resin powder, 33 parts composite plasticizer, 34 parts composite filler, 0.8 parts cellulose nanocrystals, 3.5 parts composite stabilizer, 1.2 parts crosslinking agent, 3.5 parts vinyl fluorosilicone oil, 0.4 parts (3,6-diamino-9-acridyl)boric acid, 1.8 parts coupling agent, and 3.5 parts pigment white.

[0043] The PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of 1.2:0.9:3.5; the bimodal polyvinyl chloride paste resin is prepared according to the method of Example 1 of Chinese Invention Patent No. CN105440219B; the composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetylacetonate in a mass ratio of 3.5:1.5:2; the composite filler is a mixture of graphene-modified nano-calcium carbonate and needle-shaped wollastonite powder in a mass ratio of 3.5:2.3.

[0044] The preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.45 mol / L calcium chloride solution to a reaction vessel, heating to 59℃, stirring at a rate of 490 r / min, slowly adding 0.45 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 8.3, and reacting for 32 min; controlling the reaction temperature at 70℃, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 82℃ for 3.5 h to obtain graphene-modified nano-calcium carbonate; the mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3; the concentration of the graphene dispersion is 0.5 mg / mL; the graphene is single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm; the aspect ratio of the needle-like wollastonite powder is 16:1, and the average particle size is 1800 mesh.

[0045] The cellulose nanocrystals have a diameter of 10-50 nm and a length of 200-500 nm, and are designated as TL-003. The composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:0.35. The calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2. The heat-resistant modifier is Kanekachi A-15 from Japan. The hydrotalcite is ALCAMIZER® 1-C hydrotalcite. The crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of 1.3:1. The vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019. The coupling agent is silane coupling agent KH560. The pigment white is rutile titanium dioxide R902.

[0046] A method for preparing the aforementioned temperature-resistant and weather-resistant sealant includes the following steps: Step S1, Mixing: Liquid materials are pumped into the mixing vessel using a metering pump, and solid materials are added by weight; ultrasonic dispersion is performed for 23 minutes, followed by stirring at 1100 rpm for 12 minutes; the ultrasonic power of the ultrasonic dispersion is 300W and the frequency is 40kHz. Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank and left for 19 hours. Then, it is vacuumed for 32 minutes under a vacuum pressure of -0.06MPa. Next, the product is filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant. Example 3

[0047] A temperature- and weather-resistant sealant, by weight, comprises the following raw materials: 40 parts PVC resin powder, 35 parts composite plasticizer, 36 parts composite filler, 1 part cellulose nanocrystals, 4 parts composite stabilizer, 1.5 parts crosslinking agent, 4 parts vinyl fluorosilicone oil, 0.5 parts (3,6-diamino-9-acridyl)boric acid, 2 parts coupling agent, and 4 parts pigment white.

[0048] The PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of 1.5:1:4; the bimodal polyvinyl chloride paste resin is prepared according to the method of Example 1 of Chinese Invention Patent No. CN105440219B; the composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetylacetonate in a mass ratio of 4:2:2; the composite filler is a mixture of graphene-modified nano-calcium carbonate and needle-shaped wollastonite powder in a mass ratio of 4:2.5.

[0049] The preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.5 mol / L calcium chloride solution to a reaction vessel, heating to 60°C, stirring at 500 r / min, slowly adding 0.5 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 8.5, and reacting for 33 min; controlling the reaction temperature at 70°C, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 83°C for 4 h to obtain graphene-modified nano-calcium carbonate; The mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3; the concentration of the graphene dispersion is 0.5 mg / mL; the graphene is a single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm; the aspect ratio of the needle-like wollastonite powder is 17:1, and the average particle size is 2000 mesh; the cellulose nanocrystals have a diameter of 10-50 nm, a length of 200-500 nm, and are model TL-003.

[0050] The composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:0.4; the calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2; the heat-resistant modifier is Kanekachi A-15 from Japan; the hydrotalcite is ALCAMIZER® 1-C hydrotalcite; the crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of 1.5:1; the vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019; the coupling agent is silane coupling agent KH560; and the pigment white is rutile titanium dioxide R902.

[0051] A method for preparing the aforementioned temperature-resistant and weather-resistant sealant includes the following steps: Step S1, Mixing: Liquid materials are pumped into the mixing vessel using a metering pump, and solid materials are added by weight; ultrasonic dispersion is performed for 25 minutes, followed by stirring at 1150 rpm for 13 minutes; the ultrasonic power of the ultrasonic dispersion is 300 W and the frequency is 40 kHz. Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank and left for 20 hours. Then, it is vacuumed for 35 minutes under a vacuum pressure of -0.08MPa. Next, the product is filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant. Example 4

[0052] A temperature- and weather-resistant sealant, by weight, comprises the following raw materials: 43 parts PVC resin powder, 38 parts composite plasticizer, 38 parts composite filler, 1.3 parts cellulose nanocrystals, 4.5 parts composite stabilizer, 1.8 parts crosslinking agent, 4.5 parts vinyl fluorosilicone oil, 0.7 parts (3,6-diamino-9-acridyl)boric acid, 2.3 parts coupling agent, and 4.5 parts pigment white.

[0053] The PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of 1.8:1.1:4.5; the bimodal polyvinyl chloride paste resin is prepared according to the method of Example 1 of Chinese Invention Patent No. CN105440219B; the composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetylacetonate in a mass ratio of 4.5:2.5:2; the composite filler is a mixture of graphene-modified nano-calcium carbonate and needle-shaped wollastonite powder in a mass ratio of 4.5:2.8.

[0054] The preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.55 mol / L calcium chloride solution to a reaction vessel, heating to 61℃, stirring at a rate of 510 r / min, slowly adding 0.55 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 8.8, and reacting for 34 min; controlling the reaction temperature at 70℃, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 84℃ for 4.5 h to obtain graphene-modified nano-calcium carbonate; the mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3; the concentration of the graphene dispersion is 0.5 mg / mL; the graphene is single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm.

[0055] The needle-shaped wollastonite powder has an aspect ratio of 18:1 and an average particle size of 2000 mesh; the cellulose nanocrystals have a diameter of 10-50 nm and a length of 200-500 nm, and are designated as TL-003; the composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:0.45; the calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2; the heat-resistant modifier is Kanekachi A-15 (Japan); the hydrotalcite is ALCAMIZER® 1-C hydrotalcite; the crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of 1.8:1; the vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019; the coupling agent is silane coupling agent KH560; and the pigment white is rutile titanium dioxide R902.

[0056] A method for preparing the aforementioned temperature-resistant and weather-resistant sealant includes the following steps: Step S1, Mixing: Liquid materials are pumped into the mixing vessel using a metering pump, and solid materials are added by weight; ultrasonic dispersion is performed for 28 minutes, followed by stirring at 1250 rpm for 14 minutes; the ultrasonic power of the ultrasonic dispersion is 300 W and the frequency is 40 kHz. Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank for 21 hours, and then vacuumed for 38 minutes at a vacuum pressure of -0.09MPa. Then, the product is filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant. Example 5

[0057] A temperature- and weather-resistant sealant, by weight, comprises the following raw materials: 45 parts PVC resin powder, 40 parts composite plasticizer, 40 parts composite filler, 1.5 parts cellulose nanocrystals, 5 parts composite stabilizer, 2 parts crosslinking agent, 5 parts vinyl fluorosilicone oil, 0.8 parts (3,6-diamino-9-acridyl)boric acid, 2.5 parts coupling agent, and 5 parts pigment white.

[0058] The PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of 2:1.2:5; the bimodal polyvinyl chloride paste resin is prepared according to the method of Example 1 of Chinese Invention Patent No. CN105440219B; the composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetylacetonate in a mass ratio of 5:3:2; the composite filler is a mixture of graphene-modified nano-calcium carbonate and needle-shaped wollastonite powder in a mass ratio of 5:3.

[0059] The preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.6 mol / L calcium chloride solution to a reaction vessel, heating to 62℃, stirring at 520 r / min, slowly adding 0.6 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 9, and reacting for 35 min; controlling the reaction temperature at 70℃, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 85℃ for 5 h to obtain graphene-modified nano-calcium carbonate; the mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3; the concentration of the graphene dispersion is 0.5 mg / mL; the graphene is single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm; the aspect ratio of the needle-like wollastonite powder is 18:1, and the average particle size is 2500 mesh.

[0060] The cellulose nanocrystals have a diameter of 10-50 nm and a length of 200-500 nm, and are designated as TL-003. The composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:0.5. The calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2. The heat-resistant modifier is Kanekachi A-15 from Japan. The hydrotalcite is ALCAMIZER® 1-C hydrotalcite. The crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of 2:1. The vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019. The coupling agent is silane coupling agent KH560. The pigment white is rutile titanium dioxide R902.

[0061] A method for preparing the aforementioned temperature-resistant and weather-resistant sealant includes the following steps: Step S1, Mixing: Liquid materials are pumped into the mixing vessel using a metering pump, and solid materials are added by weight; ultrasonic dispersion is performed for 30 minutes, followed by stirring at 1300 rpm for 15 minutes; the ultrasonic power of the ultrasonic dispersion is 300W and the frequency is 40kHz. Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank and left for 22 hours. Then, it is vacuumed for 40 minutes under a vacuum pressure of -0.1MPa. Next, the product is filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant.

[0062] Comparative Example 1 A temperature- and weather-resistant sealant and its preparation method are basically the same as in Example 1, except that the PVC resin powder is PA1384 and (3,6-diamino-9-acridyl)boronic acid is not added.

[0063] Comparative Example 2 A temperature- and weather-resistant sealant and its preparation method are basically the same as in Example 1, except that cellulose nanocrystals and vinyl fluorosilicone oil are not added.

[0064] To further illustrate the beneficial technical effects of the temperature-resistant and weather-resistant sealants involved in the various embodiments of the present invention, relevant performance tests were conducted on the temperature-resistant and weather-resistant sealants involved in Examples 1-5 and Comparative Examples 1-2. The curing conditions for the sealant samples used in the tests were: 150℃, 25min. The test results are shown in Table 1, and the test methods are as follows: (1) Shear strength: The shear performance of each sealant at 23℃ was tested in accordance with GB / T37126-2018.

[0065] (2) Tensile strength: Referring to GB / T 528-2009, the cured sealant was made into a type 1 dumbbell-shaped specimen for tensile strength testing at a tensile speed of 500 mm / min.

[0066] (3) Temperature resistance: The cured sealant of each example was placed at -40℃ for 24 hours, then placed at 160℃ for 24 hours. After returning to room temperature, the tensile strength was tested again according to the tensile strength test method in (2), and the tensile strength retention rate was calculated. The larger the value, the better the temperature resistance.

[0067] (4) Weather resistance: The cured sealant of each example was placed at 85°C and 85% relative humidity for 1000 hours. After returning to room temperature, the tensile strength was tested again according to the tensile strength test method in (2), and the tensile strength retention rate was calculated. The larger the value, the better the weather resistance.

[0068] Table 1 Test Results of Temperature and Weather Resistance Sealants Shear strength (MPa) 2.86 2.97 3.12 3.17 3.25 2.57 2.63 Tensile strength (MPa) 8.51 8.60 8.65 8.77 8.85 7.79 7.26 Temperature resistance (%) 96.13 96.63 96.92 97.15 97.63 92.43 91.60 Weather resistance (%) 98.71 99.07 99.42 99.66 99.77 95.51 94.77 As can be seen from Table 1, the temperature-resistant and weather-resistant sealant of the present invention has superior bonding performance, temperature resistance, and weather resistance compared to the comparative product. The combined use of (3,6-diamino-9-acridyl)boric acid, cellulose nanocrystals, vinyl fluorosilicone oil, PCMA-12, and bimodal polyvinyl chloride paste resin is beneficial to improving the above-mentioned properties.

[0069] The above embodiments are only for illustrating the technical concept and features of the present invention. Their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A temperature- and weather-resistant sealant, characterized in that, The product, by weight, comprises the following raw materials: 35-45 parts PVC resin powder, 30-40 parts composite plasticizer, 30-40 parts composite filler, 0.5-1.5 parts cellulose nanocrystals, 3-5 parts composite stabilizer, 1-2 parts crosslinking agent, 3-5 parts vinyl fluorosilicone oil, 0.3-0.8 parts (3,6-diamino-9-acridyl)boric acid, 1.5-2.5 parts coupling agent, and 3-5 parts pigment white; the PVC resin powder is a mixture of PA1384, PCMA-12, and bimodal polyvinyl chloride paste resin in a mass ratio of (1-2):(0.8-1.2):(3-5); the composite plasticizer is a mixture of epoxidized soybean oil, trioctyl trimellitate, and tributyl acetylacetonate in a mass ratio of (3-5):(1-3):2; the composite filler... The material is a mixture of graphene-modified nano-calcium carbonate and acicular wollastonite powder in a mass ratio of (3-5):(2-3); the aspect ratio of the acicular wollastonite powder is (15-18):1, and the particle size is 1500-2500 mesh; the composite stabilizer is a mixture of calcium-zinc composite stabilizer, hydrotalcite, β-diketone, and heat-resistant modifier in a mass ratio of 5:3:2:(0.3-0.5); the calcium-zinc composite stabilizer is calcium-zinc composite stabilizer CZ-106-2; the heat-resistant modifier is Kanekachi A-15 from Japan; the hydrotalcite is ALCAMIZER® 1-C hydrotalcite; the pigment white is rutile titanium dioxide R902; the bimodal polyvinyl chloride paste resin contains 5-20% small particles with a particle size of 0.2-0.7 μm, and the remainder consists of large particles with a particle size of 1 μm.

2. The temperature-resistant and weather-resistant sealant according to claim 1, characterized in that, The preparation method of the graphene-modified nano-calcium carbonate includes the following steps: adding 0.4-0.6 mol / L calcium chloride solution to a reaction vessel, heating to 58-62℃, stirring at a rate of 480-520 r / min, slowly adding 0.4-0.6 mol / L sodium carbonate solution, and simultaneously adding graphene dispersion, adjusting the pH value to 8-9, and reacting for 30-35 min; controlling the reaction temperature at 70℃, continuing to add stearic acid and reacting for 1 h, then filtering, washing, and vacuum drying at 80-85℃ for 3-5 h to obtain graphene-modified nano-calcium carbonate.

3. The temperature-resistant and weather-resistant sealant according to claim 2, characterized in that, The mass ratio of calcium chloride, sodium carbonate, graphene, and stearic acid is 111:106:0.5:0.3; the concentration of the graphene dispersion is 0.5 mg / mL; the graphene is a single-layer graphene with a thickness of 0.8-1.2 nm and a diameter of 0.5-5 μm.

4. The temperature-resistant and weather-resistant sealant according to claim 1, characterized in that, The cellulose nanocrystals have a diameter of 10-50 nm and a length of 200-500 nm.

5. The temperature-resistant and weather-resistant sealant according to claim 1, characterized in that, The crosslinking agent is a mixture of vinyltriethoxysilane and dicumyl peroxide in a mass ratio of (1-2):1; the vinyl fluorosilicone oil is vinyl fluorosilicone oil TPD-FS8019; and the coupling agent is silane coupling agent KH560.

6. A method for preparing a temperature- and weather-resistant sealant according to any one of claims 1-5, characterized in that, Includes the following steps: Step S1, Mixing: Pump the liquid material into the mixing vessel using a metering pump, and add the solid material by weight; ultrasonically disperse for 20-30 minutes, and then stir at 1000-1300 rpm for 10-15 minutes; Step S2, Grinding: Pass the well-stirred material through a three-roll mill until the fineness is less than 60μm; Step S3, vacuuming and filtration: After grinding, the material is placed in a vacuum tank and left for 18-22 hours. Then, vacuuming is performed for 30-40 minutes under a vacuum pressure of -0.05 MPa to -0.1 MPa. The product is then filtered using a 60-mesh double-pressure filter to obtain the temperature-resistant and weather-resistant sealant.

7. The method for preparing the temperature-resistant and weather-resistant sealant according to claim 6, characterized in that, The ultrasonic power of the ultrasonic dispersion in step S1 is 300W and the frequency is 40kHz.