Uvioresistant coating composition for tent and preparation method thereof

Abstract

The invention provides an anti-ultraviolet coating composition for tents and a preparation method thereof, and belongs to the technical field of paints.The preparation method comprises the following steps that S1, thiophene-2-boric acid is dissolved in absolute ethyl alcohol, zinc oxide microspheres are added, a reflux reaction is conducted, and modified zinc oxide microspheres are obtained; s2, adding tetrabutyl titanate and tetraethoxysilane into absolute ethyl alcohol, dissolving, adding a deionized water solution containing nitric acid, heating and stirring to form transparent gel, aging, drying, grinding, and calcining to obtain TiO2 / SiO2 composite nanoparticles; and S3, adding dimethylolpropionic acid modified polyurethane, epoxidized soybean oil and an auxiliary agent into a reaction kettle, heating and stirring, adding the modified zinc oxide microspheres and the TiO2 / SiO2 composite nanoparticles, and uniformly mixing to obtain the anti-ultraviolet coating composition for the tent. According to the invention, the purpose of good anti-ultraviolet performance of the coating composition can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly to an anti-ultraviolet coating composition for tents and a preparation method thereof. Background Art

[0002] In recent years, outdoor equipment such as tents has increasingly higher requirements for anti-ultraviolet, weather resistance and mechanical properties. Traditional anti-ultraviolet coatings mostly rely on single ultraviolet absorbers (such as zinc oxide or titanium dioxide), but they have the following defects: (1) The interfacial compatibility between inorganic nanoparticles and organic resin matrix is poor, and agglomeration is easy to occur, resulting in a decrease in the coating uniformity; (2) The ultraviolet shielding band of a single component is limited, and it is difficult to achieve efficient protection in the full band; (3) The coating is prone to photocatalytic degradation in high-temperature or humid environments, reducing the service life.

[0003] The patent document with the publication number CN105331251A discloses an anti-ultraviolet outdoor epoxy resin coating, and the components included are alicyclic glycidyl ether epoxy resin, alicyclic glycidyl ester-based epoxy resin, zinc oxide particles, talcum powder, quartz sand, xylene, n-butanol, butyl acetate, dispersant, defoamer and leveling agent. This patent only uses zinc oxide as the filler for absorbing ultraviolet rays, and the components are single, and full-band protection cannot be achieved. The patent document with the publication number CN104194633A discloses an anti-ultraviolet fireproof coating, and its components are composed of the following components by weight percentage: 80% - 90% of component A and 10% - 20% of component B; Component A includes the following components by weight parts: 30 - 50 parts of vinyl resin, 20 - 25 parts of coloring pigment, 1 - 8 parts of auxiliary agent, 0.4 - 0.6 parts of mixed solvent; The auxiliary agent includes an anti-ultraviolet auxiliary agent, an anti-settling agent and a defoamer; The mixed solvent includes ethyl acetate and dimethyldiethoxysilane; Component B includes the following components by weight parts: 15 - 20 parts of cobalt naphthenate, 10 - 20 parts of melamine pyrophosphate, 20 - 30 parts of propylene glycol, 15 - 20 parts of talcum powder. The coating prepared by this patent has flame retardancy and certain anti-ultraviolet performance, but the problem of easy photocatalytic degradation of the coating is not solved.

[0004] Therefore, a preparation method of an anti-ultraviolet coating composition for tents is needed to solve the problems existing in the above-mentioned prior art. Summary of the Invention

[0005] In view of this, the present invention provides an anti-ultraviolet coating composition for tents and a preparation method thereof, which can achieve the purpose of strong anti-ultraviolet ability of the coating composition.

[0006] The specific solution of the present invention is as follows. A preparation method of an anti-ultraviolet coating composition for tents includes the following steps: Step S1, preparation of modified zinc oxide microspheres: Dissolve thiophene-2-boronic acid in absolute ethanol, add zinc oxide microspheres, stir, transfer to a three-necked flask for reflux reaction, cool, centrifuge, wash the precipitate with absolute ethanol, and dry in vacuum to obtain modified zinc oxide microspheres; Step S2: Preparation of TiO2 / SiO2 composite nanoparticles: Add tetrabutyl titanate and tetraethyl orthosilicate to absolute ethanol, stir until completely dissolved, add deionized aqueous solution containing nitric acid, heat and stir to form a transparent gel, age, grind after drying, and calcine to obtain TiO2 / SiO2 composite nanoparticles; Step S3: Preparation of the coating composition: Add dimethylolpropionic acid modified polyurethane, epoxy soybean oil and additives to a reaction kettle, heat and stir, and then add the modified zinc oxide microspheres and the TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0007] The thiophene ring in the molecular structure of thiophene-2-boronic acid has a broad-spectrum ultraviolet absorption ability, which can cover the UVA long-wave region that is difficult to reach by traditional inorganic fillers, forming a full-band protection network of "inorganic reflection + organic absorption". The boronic acid group in the molecular structure of thiophene-2-boronic acid can react with the hydroxyl groups on the surface of zinc oxide to form strong B-O-Zn covalent bonds, upgrading the originally physically adsorbed filler-resin interface to a chemical bond. This bond not only greatly improves the dispersion stability of the filler, but also constructs a three-dimensional cross-linked network inside the coating, enhancing the mechanical strength. And the dynamic reversible characteristics of the borate bond endow the coating with certain self-healing ability. When the coating generates microscopic cracks due to external forces, the boronic acid groups at the broken bond can spontaneously re-bond with adjacent hydroxyl groups to achieve autonomous crack repair. This repair mechanism enables the coating to always maintain a dense structure during long-term use, greatly delaying the process of coating performance deterioration and effectively extending the service life of the coating.

[0008] The zinc oxide microspheres have a hollow structure, and the air sandwich formed by the cavity can trap the incident ultraviolet light inside the microspheres through multiple reflection and scattering effects, significantly extending the optical path and enhancing the shielding efficiency. At the same time, the static air in the cavity has a low thermal conductivity, endowing the coating with an additional heat insulation function and hindering the diffusion of heat into the interior space of the tent.

[0009] The flexibility and high elasticity of polyurethane endow the coating with good mechanical strength and durability, enabling the tent fabric to meet the deformation requirements under dynamic stresses such as strong winds and repeated folding. After modifying polyurethane with dimethylolpropionic acid, dimethylolpropionic acid-modified polyurethane is obtained. An active carboxyl group is introduced into its molecular chain, which can form directional chemical bonds with hydroxyl or amino groups on the surfaces of common tent substrates such as polyester and nylon, significantly enhancing the interfacial adhesion of the coating, enabling the coating to remain intact under service environments such as rainwashing and friction scuffing, and avoiding the risk of peeling.

[0010] Preferably, in the step S1, the reflux reaction is carried out under an oil bath condition, the reaction temperature is 75 - 85 °C, and the time is 2 - 3.5 h.

[0011] Preferably, in the step S2, the ratio of tetrabutyl titanate to tetraethyl orthosilicate is 1:1.

[0012] Preferably, in the step S2, the stirring speed is 400 - 600 r / min; the temperature for heating and stirring is 55 - 65 °C, and the time is 5 - 6.5 h.

[0013] Preferably, in the step S2, the concentration of nitric acid in the deionized aqueous solution containing nitric acid is 0.01 M.

[0014] Preferably, in the step S3, the temperature for heating and stirring is 55 - 65 °C, the speed is 500 - 600 r / min, and the time is 40 - 60 min.

[0015] Preferably, in the step S3, 3-carene is also added when adding modified zinc oxide microspheres and TiO2 / SiO2 composite nanoparticles.

[0016] The bicyclic terpene structure of 3-carene has active double bonds, which can efficiently capture free radicals generated by ultraviolet light and interrupt the chain reaction of resin oxidation. This free radical quenching mechanism not only slows down the yellowing and embrittlement of the resin matrix but also indirectly protects other functional components from oxidation erosion, enhancing the antioxidant property of the coating. At the same time, the small molecule property of 3-carene enables it to penetrate between polymer chain segments, significantly enhancing the flexibility of the coating in low-temperature environments and avoiding brittle cracking caused by severe cold. In addition, its hydrophobicity can regulate the surface wettability of the filler and promote the uniform dispersion of nanoparticles in the resin.

[0017] Preferably, the auxiliary agent includes zinc stearate and aluminum hydroxide.

[0018] Zinc stearate is a metal soap compound with good lubricity. During the coating preparation process, it can reduce the viscosity of the mixture, improve the processing fluidity, make each component more easily dispersed and uniform, and at the same time reduce the friction of the inner wall of the reaction kettle or the stirring device, thus improving the production efficiency. Zinc stearate has hydrophobic properties and can enhance the waterproof performance of the coating. In addition, it can improve the surface smoothness of the coating, reduce dirt adhesion, and indirectly extend the service life of the coating. Zinc stearate can inhibit the thermal decomposition of the resin during heating, prevent material deterioration caused by high temperature during processing, and ensure the stable performance of the coating.

[0019] Aluminum hydroxide is an efficient halogen-free flame retardant. When the coating is exposed to fire or high temperature, aluminum hydroxide absorbs heat and decomposes into alumina and water vapor. This process not only absorbs a large amount of heat, reduces the surface temperature of the material, but also dilutes the oxygen concentration by the released water vapor to inhibit the combustion reaction. And the inert gas and alumina residue generated during the decomposition of aluminum hydroxide can reduce the release of toxic smoke during combustion, and also help to block the spread of fire, improving the safety of the tent. As an inorganic filler, aluminum hydroxide can increase the rigidity and wear resistance of the coating while reducing the material cost.

[0020] To achieve the above object, the present invention also provides a tent anti-ultraviolet coating composition prepared by the preparation method of the above-mentioned tent anti-ultraviolet coating composition, which is characterized in that it comprises the following components in parts by weight: 40 - 50 parts of modified zinc oxide microspheres, 15 - 20 parts of TiO2 / SiO2 composite nanoparticles, 90 - 100 parts of dimethylolpropionic acid modified polyurethane, 30 - 35 parts of epoxy soybean oil, and 10 - 15 parts of additives.

[0021] Preferably, it also comprises the following components in parts by weight: 0.5 - 1 part of 3-carene; The raw materials of the modified zinc oxide microspheres include: 25 - 30 parts of thiophene-2-boric acid and 50 - 60 parts of zinc oxide microspheres; the raw materials of the TiO2 / SiO2 composite nanoparticles include: 20 - 25 parts of tetrabutyl titanate and 20 - 25 parts of tetraethyl orthosilicate.

[0022] The above technical solutions of the present invention at least include the following beneficial effects: (1) The thiophene ring in the molecular structure of thiophene-2-boric acid has broad-spectrum ultraviolet absorption ability, which can improve the anti-ultraviolet ability of the coating. The boric acid group in its molecular structure can react with the hydroxyl groups on the surface of zinc oxide to form strong B-O-Zn bonds, which can greatly improve the dispersion stability of the filler and also enhance the mechanical strength of the coating. And the dynamic reversible characteristics of the borate bond endow the coating with certain self-healing ability, which helps the coating maintain a dense structure during long-term use and effectively extends the service life of the coating.

[0023] (2) The zinc oxide microspheres have a hollow structure, which can extend the ultraviolet light path and enhance the shielding efficiency through multiple reflection and scattering effects. At the same time, the static air in its cavity has a low thermal conductivity, endowing the coating with an additional heat insulation function.

[0024] (3) The flexibility and high elasticity of polyurethane endow the coating with good mechanical strength and durability. After carboxyl modification, active carboxyl groups are introduced into the polyurethane molecular chain, which can significantly improve the interfacial adhesion of the coating and enhance the environmental adaptability of the coating. Specific Embodiments

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. The described embodiments are some of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention fall within the scope of protection of the present invention.

[0026] Example 1 Dissolve 30 parts of thiophene-2-boric acid in absolute ethanol, add 55 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux and react in an 80°C oil bath for 3 h, cool and centrifuge for 10 min to separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a 60°C vacuum oven and dry for 6 h to obtain modified zinc oxide microspheres.

[0027] Add 25 parts of tetrabutyl titanate and 25 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 500 r / min until completely dissolved, then slowly dropwise add 18 parts of deionized aqueous solution containing nitric acid, and raise the temperature to 60°C and continue stirring for 5.5 h to form a transparent sol. After standing and aging for 24 h, dry at 60°C to obtain a gel precursor, grind it into powder and place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0028] Add 95 parts of dimethylolpropionic acid modified polyurethane, 30 parts of epoxidized soybean oil, 3 parts of zinc stearate and 7 parts of aluminum hydroxide to a reaction kettle, heat to 60°C, stir at a speed of 500 r / min for 60 min, then add 40 parts of modified zinc oxide microspheres, 0.5 part of 3-carene and 20 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0029] Example 2 Dissolve 25 parts of thiophene-2-boric acid in absolute ethanol, add 50 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux and react in an oil bath at 85 °C for 2 h, cool and then centrifuge for 10 min to separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a vacuum oven at 60 °C and dry it for 6 h to obtain modified zinc oxide microspheres.

[0030] Add 20 parts of tetrabutyl titanate and 20 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 600 r / min until completely dissolved, then slowly add 18 parts of deionized aqueous solution containing nitric acid, heat to 65 °C and continuously stir for 5 h to form a transparent sol. After standing and aging for 24 h, dry at 60 °C to obtain a gel precursor, grind it into powder and then place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0031] Add 100 parts of dimethylolpropionic acid modified polyurethane, 35 parts of epoxy soybean oil, 4 parts of zinc stearate and 10 parts of aluminum hydroxide to a reaction kettle, heat to 60 °C, stir at a speed of 500 r / min for 60 min, then add 45 parts of modified zinc oxide microspheres, 1 part of 3-carene and 20 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0032] Example 3 Dissolve 27 parts of thiophene-2-boric acid in absolute ethanol, add 60 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux and react in an oil bath at 75 °C for 3.5 h, cool and then centrifuge for 10 min to separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a vacuum oven at 60 °C and dry it for 6 h to obtain modified zinc oxide microspheres.

[0033] Add 20 parts of tetrabutyl titanate and 20 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 400 r / min until completely dissolved, then slowly add 18 parts of deionized aqueous solution containing nitric acid, heat to 55 °C and continuously stir for 6.5 h to form a transparent sol. After standing and aging for 24 h, dry at 60 °C to obtain a gel precursor, grind it into powder and then place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0034] Add 90 parts of dimethylolpropionic acid modified polyurethane, 35 parts of epoxy soybean oil, 5 parts of zinc stearate and 10 parts of aluminum hydroxide to a reaction kettle, heat to 60 °C, stir at a speed of 600 r / min for 40 min, then add 50 parts of modified zinc oxide microspheres, 0.5 part of 3-carene and 15 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0035] Example 4 Dissolve 27 parts of thiophene-2-boric acid in absolute ethanol, add 55 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux and react in an 80 °C oil bath for 2.5 h, centrifuge for 10 min after cooling, separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a 60 °C vacuum oven and dry for 6 h to obtain modified zinc oxide microspheres.

[0036] Add 22 parts of tetrabutyl titanate and 22 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 600 r / min until completely dissolved, then slowly add 18 parts of deionized aqueous solution containing nitric acid, heat to 60 °C and continue stirring for 6 h to form a transparent sol. After standing and aging for 24 h, dry at 60 °C to obtain a gel precursor, grind it into powder and place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0037] Add 100 parts of dimethylolpropionic acid modified polyurethane, 30 parts of epoxy soybean oil, 3 parts of zinc stearate and 9 parts of aluminum hydroxide to a reaction kettle, heat to 60 °C, stir at a speed of 550 r / min for 55 min, then add 40 parts of modified zinc oxide microspheres, 1 part of 3-carene and 20 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0038] Example 5 Dissolve 25 parts of thiophene-2-boric acid in absolute ethanol, add 50 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux and react in an 85 °C oil bath for 2 h, centrifuge for 10 min after cooling, separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a 60 °C vacuum oven and dry for 6 h to obtain modified zinc oxide microspheres.

[0039] Add 20 parts of tetrabutyl titanate and 20 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 600 r / min until completely dissolved, then slowly add 18 parts of deionized aqueous solution containing nitric acid, heat to 65 °C and continue stirring for 5 h to form a transparent sol. After standing and aging for 24 h, dry at 60 °C to obtain a gel precursor, grind it into powder and place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0040] Add 95 parts of dimethylolpropionic acid modified polyurethane, 30 parts of epoxy soybean oil, 3 parts of zinc stearate and 10 parts of aluminum hydroxide to a reaction kettle, heat to 60 °C, stir at a speed of 500 r / min for 60 min, then add 40 parts of modified zinc oxide microspheres, 0.5 part of 3-carene and 20 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0041] Example 6 Dissolve 30 parts of thiophene-2-boric acid in absolute ethanol, add 55 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux the reaction in an 80 °C oil bath for 3 h, centrifuge for 10 min after cooling, separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a 60 °C vacuum oven and dry it for 6 h to obtain modified zinc oxide microspheres.

[0042] Add 25 parts of tetrabutyl titanate and 25 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 500 r / min until completely dissolved, then slowly add 18 parts of deionized aqueous solution containing nitric acid, raise the temperature to 60 °C and continuously stir for 5.5 h to form a transparent sol. After standing and aging for 24 h, dry it at 60 °C to obtain a gel precursor, grind it into powder and then place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0043] Add 100 parts of dimethylolpropionic acid modified polyurethane, 30 parts of epoxidized soybean oil, 5 parts of zinc stearate and 9 parts of aluminum hydroxide to a reaction kettle, heat to 60 °C, stir at a speed of 600 r / min for 45 min, then add 40 parts of modified zinc oxide microspheres, 1 part of 3-carene and 20 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0044] Example 7 Dissolve 30 parts of thiophene-2-boric acid in absolute ethanol, add 55 parts of zinc oxide microspheres, and stir magnetically for 30 min. Subsequently, transfer the mixture to a three-necked flask, reflux the reaction in an 80 °C oil bath for 3 h, centrifuge for 10 min after cooling, separate the precipitate, and wash it three times with absolute ethanol to remove unreacted substances. Finally, place the precipitate in a 60 °C vacuum oven and dry it for 6 h to obtain modified zinc oxide microspheres.

[0045] Add 25 parts of tetrabutyl titanate and 25 parts of tetraethyl orthosilicate to absolute ethanol in a ratio of 1:1, stir at a speed of 500 r / min until completely dissolved, then slowly add 18 parts of deionized aqueous solution containing nitric acid, raise the temperature to 60 °C and continuously stir for 5.5 h to form a transparent sol. After standing and aging for 24 h, dry it at 60 °C to obtain a gel precursor, grind it into powder and then place it in a muffle furnace for calcination to obtain TiO2 / SiO2 composite nanoparticles.

[0046] Add 100 parts of dimethylolpropionic acid modified polyurethane, 30 parts of epoxidized soybean oil, 5 parts of zinc stearate and 9 parts of aluminum hydroxide to a reaction kettle, heat to 60 °C, stir at a speed of 600 r / min for 45 min, then add 40 parts of modified zinc oxide microspheres and 20 parts of TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

[0047] The present invention also carried out comparative examples and related tests.

[0048] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, the preparation of modified zinc oxide microspheres was not carried out, and only zinc oxide microspheres were used. The other components and preparation methods were the same as those in Example 1, and an anti-ultraviolet coating composition for tents was prepared.

[0049] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in Comparative Example 2, the preparation of TiO2 / SiO2 composite nanoparticles was not carried out, and only TiO2 nanoparticles were used. The other components and preparation methods were the same as those in Example 1, and an anti-ultraviolet coating composition for tents was prepared.

[0050] Comparative Example 3 Comparative Example 3 is a commercially available anti-ultraviolet coating composition for tents.

[0051] Performance detection test The adhesion, toughness, abrasion resistance, water resistance and anti-ultraviolet performance of the scribed coatings of Examples 1-7 and Comparative Examples 1-3 were tested according to the following standards.

[0052] The reference standard for the adhesion test was GB / T 9286-2021, and the scribing method was used for the test; the reference standard for the toughness test was GB / T 6742-2007, and the evaluation standard for the test result was the elongation at break; the reference standard for the anti-ultraviolet ability test was GB / T 1865-2009; the reference standard for the abrasion resistance test was GB / T 1768-2006, and the evaluation standard for the test result was (750 g / 1000 r) / mg. The smaller the wear mass, the better the abrasion resistance; the reference standard for the water resistance test was GB / T 1733-1993, and the evaluation standard for the test result was whether there were blistering and peeling phenomena. The final test results were summarized as shown in Table 1 below.

[0053] Table 1

[0054] As can be seen from Table 1 above, compared with Example 1, only zinc oxide microspheres were used in Comparative Example 1, resulting in a significant decrease in the UV resistance of the coating composition. This shows that thiophene-2-boric acid can effectively improve the UV resistance of the coating composition and achieve the purpose of absorbing UV light in the entire wavelength range. Compared with Example 1, in Comparative Example 2, TiO2 was directly used, and its wear resistance and toughness both decreased significantly, and the UV resistance also decreased. This shows that the preparation of TiO2 / SiO2 composite nanoparticles helps to disperse the nanoparticles and promotes the improvement of the strength and UV resistance of the coating composition. Compared with Example 1, all properties in Comparative Example 3 decreased. This shows that the comprehensive performance of the UV-resistant coating composition for tents prepared by the present invention is superior to that of the ordinary commercially available UV-resistant coating composition for tents.

[0055] Compared with Example 6, 3-carene was not used in Example 7. As can be seen from the results in Table 1, its toughness decreased significantly, and the UV resistance also decreased. This shows that 3-carene not only helps to improve the toughness of the coating composition, but also can capture free radicals and reduce the oxidation reaction caused by UV irradiation.

[0056] The above are the preferred embodiments of the present invention. Without departing from the principle of the present invention, those of ordinary skill in the art can also make several improvements and refinements, which should also be regarded as the protection scope of the present invention.

Claims

1. A method for preparing an anti-ultraviolet coating composition for a tent, characterized in that, It includes the following steps: Step S1, preparation of modified zinc oxide microspheres: Dissolve thiophene-2-boric acid in absolute ethanol, add zinc oxide microspheres, stir, transfer to a three-necked flask for reflux reaction, cool, centrifuge, wash the precipitate with absolute ethanol, and dry it under vacuum to obtain modified zinc oxide microspheres; Step S2, preparation of TiO2 / SiO2 composite nanoparticles: Add tetrabutyl titanate and tetraethyl orthosilicate to absolute ethanol, stir until completely dissolved, add a deionized aqueous solution containing nitric acid, heat and stir to form a transparent gel, age, grind after drying, and calcine to obtain TiO2 / SiO2 composite nanoparticles; Step S3, preparation of the coating composition: Add dimethylolpropionic acid modified polyurethane, epoxy soybean oil and additives to a reaction kettle, heat and stir, and then add the modified zinc oxide microspheres and the TiO2 / SiO2 composite nanoparticles, and mix evenly to obtain an anti-ultraviolet coating composition for tents.

2. The preparation method of an anti-ultraviolet coating composition for a tent according to claim 1, characterized in that, In step S1, the reflux reaction is carried out under oil bath conditions, the reaction temperature is 75-85 °C, and the time is 2-3.5 h.

3. The preparation method of an anti-ultraviolet coating composition for a tent according to claim 1, characterized in that, In step S2, the ratio of tetrabutyl titanate to tetraethyl orthosilicate is 1:

1.

4. The preparation method of an anti-ultraviolet coating composition for a tent according to claim 1, characterized in that, In step S2, the stirring speed is 400-600 r / min; the temperature for heating and stirring is 55-65 °C, and the time is 5-6.5 h.

5. The preparation method of an anti-ultraviolet coating composition for a tent according to claim 1, characterized in that, In step S2, the concentration of nitric acid in the deionized aqueous solution containing nitric acid is 0.01 M.

6. The preparation method of an anti-ultraviolet coating composition for a tent according to claim 1, wherein, In step S3, the temperature for heating and stirring is 55-65 °C, the speed is 500-600 r / min, and the time is 40-60 min.

7. The preparation method of an anti-ultraviolet coating composition for tents according to claim 1, characterized in that, In step S3, 3-carene is also added when adding the modified zinc oxide microspheres and the TiO2 / SiO2 composite nanoparticles.

8. The preparation method of an anti-ultraviolet coating composition for a tent according to claim 1, characterized in that, The additives include zinc stearate and aluminum hydroxide.

9. An anti-ultraviolet coating composition for tents, characterized in that, Prepared by the preparation method of an anti-ultraviolet coating composition for tents according to any one of claims 1-8, and characterized in that it includes the following components in parts by weight: 40-50 parts of modified zinc oxide microspheres, 15-20 parts of TiO2 / SiO2 composite nanoparticles, 90-100 parts of dimethylolpropionic acid modified polyurethane, 30-35 parts of epoxy soybean oil and 10-15 parts of additives.

10. A UV-resistant coating composition for tents according to claim 9, characterized in that, It also includes the following components in parts by weight: 0.5-1 part of 3-carene; The raw materials of the modified zinc oxide microspheres include: 25-30 parts of thiophene-2-boric acid and 50-60 parts of zinc oxide microspheres; the raw materials of the TiO2 / SiO2 composite nanoparticles include: 20-25 parts of tetrabutyl titanate and 20-25 parts of tetraethyl orthosilicate.

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